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Precise X-ray determinations of the crystal structure of the 1:2 complex of N-ethyl-N-methylmorpholinium and 7,7,8,8-tetracyano-p-quinodimethanide, abbreviated as MEM-TCNQ or MEM(TCNQ)2 (C7H16NO+·2C12H4N40.5-), have been performed at 293 and at 10 K. Evidence for the expected spin-Peierls transition at 19 K is not found, and this may follow from radiation damage to the crystal or from insufficient equipment sensitivity.
Supporting information
CCDC references: 170213; 170214
A crystal used in an earlier synchrotron experiment (Kepert et al., 1999)
was employed.
Both room temperature and 10 K data sets were obtained on a locally assembled
Huber 512 goniometer equipped with a Displex 202D cryogenic refrigerator
(Hendricksen et al., 1986; Larsen, 1995). A series of continuous
one-dimensional scans along the c* direction of reciprocal space showed no
detectable systematic features above the background between the Bragg peaks.
For the structure from the room temperature data set, fractional populations
x and 1 - x were refined for the atoms of the disordered MEM
molecule in its two orientations relative to the pseudo inversion centre. The
positional parameters of the disordered part of MEM molecule (atoms N33' to
O') were refined using the SAME instruction of the SHELXL97
least-squares program, and with isotropic atomic displacement parameters for
all atoms. Distances between SAME listed atoms are restrained to be the same
length as those between the corresponding following atoms of the preferred
molecule (atoms N33 to O) with an e.s.d. of 0.02 Å. For the ordered part of
the MEM molecule anisotropic atomic displacement parameters were employed for
non-hydrogen atoms, isotropic for hydrogen atoms. During refinement, the
hydrogen atoms in molecules of MEM and TCNQ at 293 K were refined using
`riding model' constraints with fixed C—H distances 0.93, 0.97 and 0.96 Å
for the CH, CH2 and CH3 groups correspondingly. Isotropic displacement
parameters of the H atoms were constrained to the Ueq/U of the bonded
carbon atoms with UH = 1.2UC in CH and CH2 groups, and UH = 1.5UC
for the H atoms of CH3 groups. The absolute structure cannot be determined
reliably because of strong correlation between pseudo centro-symmetrically
related parameters of the two unique molecules of TCNQ. Flack parameters
(Flack, 1983) were estimated to be 2(3) RT and 0.9 (8) L T, but were not
included among the refined parameters.
For both compounds, data collection: Local diffractometer control software; cell refinement: Local diffractometer control software; data reduction: PROFIT (Streltsov & Zavodnik, 1989); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997). Molecular graphics: SHELXTL (Bruker, 1997) for MEMTCNQ-RT; SHELXTL (Bruker,1997) for MEMTCNQ-LT. For both compounds, software used to prepare material for publication: SHELXTL.
(MEMTCNQ-RT) 1:2 Complex of
N-Ethyl-
N-methylmorpholine and
7,7,8,8-Tetracyano-
p-quinodimethane
top
Crystal data top
2C12H4N4·C7H16NO | F(000) = 281 |
Mr = 538.59 | Dx = 1.258 Mg m−3 |
Triclinic, P1 | Melting point: not measured K |
a = 7.803 (1) Å | Mo Kα radiation, λ = 0.71073 Å |
b = 15.353 (2) Å | Cell parameters from 12 reflections |
c = 6.985 (1) Å | θ = 12.3–16.1° |
α = 112.30 (1)° | µ = 0.08 mm−1 |
β = 74.44 (1)° | T = 293 K |
γ = 111.84 (1)° | Prism, black |
V = 710.7 (2) Å3 | 0.55 × 0.45 × 0.25 mm |
Z = 1 | |
Data collection top
Huber 512 goniometer diffractometer | Rint = 0.000 |
Radiation source: normal-focus sealed tube | θmax = 30.1°, θmin = 1.5° |
None monochromator | h = 0→10 |
ω–2θ scan | k = −21→20 |
4110 measured reflections | l = −9→9 |
4110 independent reflections | 3 standard reflections every 100 reflections |
2851 reflections with I > 2σ(I) | intensity decay: 1% |
Refinement top
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.049 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.158 | w = 1/[σ2(Fo2) + (0.0808P)2 + 0.0567P] where P = (Fo2 + 2Fc2)/3 |
S = 1.04 | (Δ/σ)max = 0.002 |
4110 reflections | Δρmax = 0.23 e Å−3 |
408 parameters | Δρmin = −0.15 e Å−3 |
24 restraints | Extinction correction: SHELXL, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.046 (8) |
Crystal data top
2C12H4N4·C7H16NO | γ = 111.84 (1)° |
Mr = 538.59 | V = 710.7 (2) Å3 |
Triclinic, P1 | Z = 1 |
a = 7.803 (1) Å | Mo Kα radiation |
b = 15.353 (2) Å | µ = 0.08 mm−1 |
c = 6.985 (1) Å | T = 293 K |
α = 112.30 (1)° | 0.55 × 0.45 × 0.25 mm |
β = 74.44 (1)° | |
Data collection top
Huber 512 goniometer diffractometer | Rint = 0.000 |
4110 measured reflections | 3 standard reflections every 100 reflections |
4110 independent reflections | intensity decay: 1% |
2851 reflections with I > 2σ(I) | |
Refinement top
R[F2 > 2σ(F2)] = 0.049 | 24 restraints |
wR(F2) = 0.158 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.04 | Δρmax = 0.23 e Å−3 |
4110 reflections | Δρmin = −0.15 e Å−3 |
408 parameters | |
Special details top
Experimental. no special detailes |
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes)
are estimated using the full covariance matrix. The cell e.s.d.'s are taken
into account individually in the estimation of e.s.d.'s in distances, angles
and torsion angles; correlations between e.s.d.'s in cell parameters are only
used when they are defined by crystal symmetry. An approximate (isotropic)
treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s.
planes. |
Refinement. Refinement of F2 against ALL reflections. The weighted R-factor
wR and goodness of fit S are based on F2, conventional
R-factors R are based on F, with F set to zero for
negative F2. The threshold expression of F2 >
σ(F2) is used only for calculating R-factors(gt) etc.
and is not relevant to the choice of reflections for refinement.
R-factors based on F2 are statistically about twice as large
as those based on F, and R- factors based on ALL data will be
even larger. |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | Occ. (<1) |
N1 | 0.3070 (6) | 0.4283 (3) | 0.3655 (7) | 0.0809 (10) | |
C2 | 0.3304 (5) | 0.3557 (3) | 0.3440 (7) | 0.0581 (9) | |
C3 | 0.3556 (5) | 0.2638 (2) | 0.3178 (5) | 0.0521 (8) | |
C4 | 0.5377 (6) | 0.2686 (3) | 0.3287 (7) | 0.0629 (10) | |
N5 | 0.6840 (5) | 0.2702 (3) | 0.3356 (8) | 0.0934 (14) | |
C6 | 0.2070 (4) | 0.1760 (2) | 0.2896 (5) | 0.0456 (7) | |
C7 | 0.2317 (5) | 0.0837 (2) | 0.2667 (5) | 0.0499 (8) | |
H7 | 0.3497 | 0.0821 | 0.2662 | 0.060* | |
C8 | 0.0872 (5) | −0.0001 (2) | 0.2459 (5) | 0.0460 (7) | |
H8 | 0.1074 | −0.0582 | 0.2329 | 0.055* | |
C9 | −0.0980 (4) | −0.0017 (2) | 0.2433 (5) | 0.0455 (7) | |
C10 | −0.1220 (4) | 0.0895 (2) | 0.2660 (5) | 0.0494 (8) | |
H10 | −0.2402 | 0.0908 | 0.2661 | 0.059* | |
C11 | 0.0222 (5) | 0.1744 (2) | 0.2874 (6) | 0.0513 (8) | |
H11 | 0.0013 | 0.2324 | 0.3008 | 0.062* | |
N12 | −0.5766 (5) | −0.0873 (3) | 0.2278 (9) | 0.0908 (13) | |
C13 | −0.4317 (5) | −0.0891 (3) | 0.2242 (7) | 0.0582 (9) | |
C14 | −0.2482 (4) | −0.0894 (2) | 0.2214 (5) | 0.0476 (8) | |
C15 | −0.2245 (5) | −0.1803 (3) | 0.1977 (6) | 0.0526 (8) | |
N16 | −0.2044 (5) | −0.2538 (2) | 0.1803 (6) | 0.0702 (9) | |
N17 | −0.3013 (6) | −0.4292 (3) | −0.3651 (7) | 0.0884 (12) | |
C18 | −0.3245 (5) | −0.3568 (3) | −0.3477 (7) | 0.0611 (9) | |
C19 | −0.3500 (5) | −0.2665 (3) | −0.3257 (6) | 0.0548 (9) | |
C20 | −0.5320 (6) | −0.2696 (3) | −0.3421 (7) | 0.0651 (10) | |
N21 | −0.6771 (6) | −0.2746 (3) | −0.3597 (7) | 0.0857 (11) | |
C22 | −0.2040 (5) | −0.1779 (2) | −0.2926 (5) | 0.0490 (8) | |
C23 | −0.2295 (4) | −0.0871 (2) | −0.2713 (5) | 0.0504 (8) | |
H23 | −0.3473 | −0.0866 | −0.2752 | 0.060* | |
C24 | −0.0853 (5) | −0.0010 (3) | −0.2454 (5) | 0.0523 (9) | |
H24 | −0.1063 | 0.0574 | −0.2292 | 0.063* | |
C25 | 0.0991 (4) | −0.0004 (2) | −0.2432 (5) | 0.0470 (7) | |
C26 | 0.1237 (5) | −0.0923 (2) | −0.2640 (6) | 0.0531 (8) | |
H26 | 0.2413 | −0.0937 | −0.2616 | 0.064* | |
C27 | −0.0209 (5) | −0.1764 (2) | −0.2868 (5) | 0.0506 (8) | |
H27 | −0.0012 | −0.2346 | −0.2989 | 0.061* | |
N28 | 0.5805 (5) | 0.0890 (3) | −0.2262 (9) | 0.0897 (12) | |
C29 | 0.4324 (6) | 0.0885 (3) | −0.2217 (7) | 0.0617 (9) | |
C30 | 0.2473 (5) | 0.0859 (2) | −0.2186 (5) | 0.0515 (8) | |
C31 | 0.2280 (6) | 0.1785 (3) | −0.1976 (6) | 0.0560 (9) | |
N32 | 0.2119 (6) | 0.2521 (3) | −0.1786 (7) | 0.0796 (11) | |
N33 | 0.0396 (6) | 0.4921 (2) | 0.0022 (6) | 0.0611 (10) | 0.835 (5) |
C34 | 0.2412 (6) | 0.4936 (3) | −0.0517 (8) | 0.0715 (13) | 0.835 (5) |
H34A | 0.2496 | 0.4354 | −0.0355 | 0.086* | 0.835 (5) |
H34B | 0.2842 | 0.4904 | −0.1974 | 0.086* | 0.835 (5) |
C35 | 0.3675 (7) | 0.5837 (3) | 0.0812 (9) | 0.0724 (14) | 0.835 (5) |
H35A | 0.4950 | 0.5812 | 0.0382 | 0.087* | 0.835 (5) |
H35B | 0.3307 | 0.5855 | 0.2265 | 0.087* | 0.835 (5) |
C36 | 0.1727 (6) | 0.6769 (3) | 0.1251 (11) | 0.100 (2) | 0.835 (5) |
H36A | 0.1704 | 0.7373 | 0.1130 | 0.120* | 0.835 (5) |
H36B | 0.1339 | 0.6796 | 0.2708 | 0.120* | 0.835 (5) |
C37 | 0.0375 (6) | 0.5890 (3) | −0.0073 (10) | 0.0849 (18) | 0.835 (5) |
H37A | 0.0711 | 0.5891 | −0.1513 | 0.102* | 0.835 (5) |
H37B | −0.0876 | 0.5947 | 0.0423 | 0.102* | 0.835 (5) |
C38 | −0.0401 (9) | 0.4777 (6) | 0.2114 (9) | 0.124 (3) | 0.835 (5) |
H38A | 0.0301 | 0.5306 | 0.3153 | 0.186* | 0.835 (5) |
H38B | −0.1680 | 0.4773 | 0.2454 | 0.186* | 0.835 (5) |
H38C | −0.0338 | 0.4159 | 0.2082 | 0.186* | 0.835 (5) |
C39 | −0.0681 (7) | 0.4062 (4) | −0.1623 (9) | 0.0925 (18) | 0.835 (5) |
H39A | −0.0121 | 0.4151 | −0.2981 | 0.111* | 0.835 (5) |
H39B | −0.0534 | 0.3459 | −0.1642 | 0.111* | 0.835 (5) |
C40 | −0.2716 (9) | 0.3930 (6) | −0.1336 (13) | 0.112 (2) | 0.835 (5) |
H40A | −0.2888 | 0.4509 | −0.1382 | 0.168* | 0.835 (5) |
H40B | −0.3273 | 0.3366 | −0.2434 | 0.168* | 0.835 (5) |
H40C | −0.3299 | 0.3830 | −0.0007 | 0.168* | 0.835 (5) |
O | 0.3567 (4) | 0.6699 (2) | 0.0602 (7) | 0.0832 (12) | 0.835 (5) |
N33' | −0.0249 (18) | 0.5001 (9) | −0.013 (2) | 0.041 (4)* | 0.165 (5) |
C34' | −0.226 (2) | 0.4999 (12) | 0.037 (4) | 0.080 (8)* | 0.165 (5) |
H34C | −0.2301 | 0.5570 | 0.0124 | 0.096* | 0.165 (5) |
H34D | −0.2671 | 0.5080 | 0.1849 | 0.096* | 0.165 (5) |
C35' | −0.361 (3) | 0.4105 (14) | −0.083 (5) | 0.090 (11)* | 0.165 (5) |
H35C | −0.4863 | 0.4149 | −0.0291 | 0.109* | 0.165 (5) |
H35D | −0.3337 | 0.4072 | −0.2288 | 0.109* | 0.165 (5) |
C36' | −0.166 (2) | 0.3161 (12) | −0.141 (4) | 0.080 (7)* | 0.165 (5) |
H36C | −0.1631 | 0.2534 | −0.1411 | 0.096* | 0.165 (5) |
H36D | −0.1280 | 0.3190 | −0.2826 | 0.096* | 0.165 (5) |
C37' | −0.031 (3) | 0.4017 (12) | 0.003 (4) | 0.094 (9)* | 0.165 (5) |
H37C | −0.0729 | 0.4010 | 0.1461 | 0.112* | 0.165 (5) |
H37D | 0.0930 | 0.3940 | −0.0401 | 0.112* | 0.165 (5) |
C38' | 0.060 (4) | 0.513 (2) | −0.223 (4) | 0.137 (15)* | 0.165 (5) |
H38D | −0.0024 | 0.4570 | −0.3286 | 0.206* | 0.165 (5) |
H38E | 0.1902 | 0.5177 | −0.2479 | 0.206* | 0.165 (5) |
H38F | 0.0480 | 0.5720 | −0.2268 | 0.206* | 0.165 (5) |
C39' | 0.082 (3) | 0.5858 (17) | 0.153 (4) | 0.144 (16)* | 0.165 (5) |
H39C | 0.0310 | 0.5743 | 0.2873 | 0.173* | 0.165 (5) |
H39D | 0.0603 | 0.6457 | 0.1622 | 0.173* | 0.165 (5) |
C40' | 0.289 (3) | 0.602 (3) | 0.115 (6) | 0.100 (11)* | 0.165 (5) |
H40D | 0.3125 | 0.5459 | 0.1180 | 0.151* | 0.165 (5) |
H40E | 0.3459 | 0.6599 | 0.2222 | 0.151* | 0.165 (5) |
H40F | 0.3406 | 0.6121 | −0.0191 | 0.151* | 0.165 (5) |
O' | −0.349 (2) | 0.3239 (10) | −0.066 (3) | 0.073 (5)* | 0.165 (5) |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
N1 | 0.084 (3) | 0.0589 (18) | 0.102 (3) | 0.0220 (17) | −0.025 (2) | 0.0199 (19) |
C2 | 0.0528 (19) | 0.0531 (18) | 0.070 (2) | 0.0118 (15) | −0.0167 (17) | 0.0195 (16) |
C3 | 0.052 (2) | 0.0531 (17) | 0.054 (2) | 0.0169 (15) | −0.0123 (16) | 0.0162 (16) |
C4 | 0.056 (2) | 0.0549 (18) | 0.082 (3) | 0.0125 (15) | −0.0169 (19) | 0.0254 (19) |
N5 | 0.053 (2) | 0.089 (3) | 0.153 (4) | 0.0187 (18) | −0.030 (2) | 0.047 (3) |
C6 | 0.0416 (15) | 0.0502 (16) | 0.0483 (19) | 0.0146 (12) | −0.0073 (14) | 0.0178 (14) |
C7 | 0.0519 (19) | 0.0528 (17) | 0.055 (2) | 0.0238 (15) | −0.0110 (16) | 0.0182 (16) |
C8 | 0.0435 (16) | 0.0492 (16) | 0.054 (2) | 0.0176 (12) | −0.0084 (14) | 0.0207 (14) |
C9 | 0.0435 (16) | 0.0510 (16) | 0.048 (2) | 0.0198 (13) | −0.0077 (14) | 0.0158 (14) |
C10 | 0.0367 (15) | 0.0531 (16) | 0.061 (2) | 0.0193 (13) | −0.0063 (14) | 0.0155 (15) |
C11 | 0.0474 (18) | 0.0532 (17) | 0.058 (2) | 0.0221 (14) | −0.0097 (16) | 0.0146 (15) |
N12 | 0.051 (2) | 0.0656 (19) | 0.158 (4) | 0.0200 (16) | −0.021 (2) | 0.032 (2) |
C13 | 0.0465 (17) | 0.0490 (16) | 0.078 (3) | 0.0159 (14) | −0.0108 (17) | 0.0167 (16) |
C14 | 0.0394 (16) | 0.0522 (17) | 0.054 (2) | 0.0140 (13) | −0.0073 (14) | 0.0189 (15) |
C15 | 0.0508 (18) | 0.0533 (17) | 0.057 (2) | 0.0174 (14) | −0.0070 (15) | 0.0203 (15) |
N16 | 0.075 (2) | 0.0579 (17) | 0.090 (2) | 0.0258 (16) | −0.0172 (19) | 0.0271 (17) |
N17 | 0.090 (3) | 0.0587 (19) | 0.116 (3) | 0.0263 (19) | −0.017 (2) | 0.021 (2) |
C18 | 0.055 (2) | 0.0531 (18) | 0.068 (2) | 0.0145 (15) | −0.0089 (17) | 0.0128 (17) |
C19 | 0.0456 (18) | 0.0590 (19) | 0.059 (2) | 0.0145 (15) | −0.0072 (16) | 0.0190 (17) |
C20 | 0.053 (2) | 0.065 (2) | 0.078 (3) | 0.0151 (16) | −0.0192 (18) | 0.0191 (19) |
N21 | 0.066 (2) | 0.084 (2) | 0.109 (3) | 0.0223 (19) | −0.030 (2) | 0.022 (2) |
C22 | 0.0533 (18) | 0.0517 (16) | 0.0459 (19) | 0.0214 (14) | −0.0081 (15) | 0.0134 (14) |
C23 | 0.0414 (16) | 0.0582 (18) | 0.058 (2) | 0.0173 (14) | −0.0108 (15) | 0.0202 (16) |
C24 | 0.0555 (19) | 0.0544 (18) | 0.057 (2) | 0.0254 (15) | −0.0106 (17) | 0.0182 (16) |
C25 | 0.0468 (16) | 0.0482 (15) | 0.049 (2) | 0.0162 (13) | −0.0046 (14) | 0.0176 (14) |
C26 | 0.0509 (18) | 0.0525 (17) | 0.064 (2) | 0.0236 (14) | −0.0070 (17) | 0.0202 (16) |
C27 | 0.0476 (17) | 0.0479 (16) | 0.061 (2) | 0.0207 (13) | −0.0037 (15) | 0.0189 (15) |
N28 | 0.048 (2) | 0.089 (2) | 0.131 (4) | 0.0181 (18) | −0.012 (2) | 0.038 (2) |
C29 | 0.052 (2) | 0.0547 (18) | 0.078 (3) | 0.0143 (15) | −0.0064 (19) | 0.0241 (18) |
C30 | 0.057 (2) | 0.0521 (18) | 0.052 (2) | 0.0244 (15) | −0.0049 (16) | 0.0181 (16) |
C31 | 0.059 (2) | 0.0533 (18) | 0.058 (2) | 0.0142 (15) | −0.0117 (17) | 0.0207 (16) |
N32 | 0.096 (3) | 0.0591 (18) | 0.091 (3) | 0.0273 (19) | −0.016 (2) | 0.0263 (18) |
N33 | 0.062 (2) | 0.0504 (17) | 0.069 (2) | 0.0170 (15) | −0.0055 (17) | 0.0196 (13) |
C34 | 0.074 (2) | 0.0516 (19) | 0.091 (3) | 0.0287 (17) | −0.013 (2) | 0.0147 (18) |
C35 | 0.067 (3) | 0.060 (2) | 0.096 (3) | 0.0212 (19) | −0.014 (2) | 0.027 (2) |
C36 | 0.058 (2) | 0.0453 (19) | 0.177 (6) | 0.0180 (16) | −0.020 (3) | 0.011 (2) |
C37 | 0.054 (2) | 0.056 (2) | 0.146 (5) | 0.0201 (16) | −0.019 (2) | 0.028 (2) |
C38 | 0.095 (4) | 0.164 (6) | 0.082 (3) | −0.012 (3) | 0.001 (3) | 0.066 (4) |
C39 | 0.079 (3) | 0.070 (3) | 0.092 (3) | 0.002 (2) | −0.021 (2) | 0.001 (2) |
C40 | 0.084 (4) | 0.120 (5) | 0.127 (5) | 0.004 (3) | −0.034 (4) | 0.046 (4) |
O | 0.0624 (16) | 0.0544 (15) | 0.140 (3) | 0.0128 (12) | −0.0214 (16) | 0.0385 (17) |
Geometric parameters (Å, º) top
N1—C2 | 1.143 (5) | C26—C27 | 1.350 (5) |
C2—C3 | 1.432 (5) | C27—C22 | 1.432 (5) |
C3—C4 | 1.417 (6) | N28—C29 | 1.145 (5) |
C3—C6 | 1.400 (5) | C29—C30 | 1.424 (6) |
C4—N5 | 1.146 (5) | C30—C25 | 1.385 (5) |
C6—C7 | 1.444 (5) | C30—C31 | 1.433 (5) |
C7—C8 | 1.347 (5) | C31—N32 | 1.137 (5) |
C8—C9 | 1.440 (5) | N33—C34 | 1.509 (5) |
C9—C10 | 1.426 (5) | N33—C37 | 1.520 (5) |
C10—C11 | 1.356 (5) | N33—C38 | 1.492 (6) |
C11—C6 | 1.437 (4) | N33—C39 | 1.519 (5) |
N12—C13 | 1.135 (5) | C34—C35 | 1.499 (6) |
C13—C14 | 1.428 (5) | C35—O | 1.420 (5) |
C14—C9 | 1.405 (4) | C36—O | 1.417 (5) |
C14—C15 | 1.418 (5) | C36—C37 | 1.518 (6) |
C15—N16 | 1.154 (5) | C39—C40 | 1.491 (8) |
N17—C18 | 1.149 (5) | N33'—C34' | 1.509 (14) |
C18—C19 | 1.418 (5) | N33'—C37' | 1.538 (15) |
C19—C20 | 1.438 (5) | N33'—C38' | 1.494 (16) |
C19—C22 | 1.397 (5) | N33'—C39' | 1.520 (16) |
C20—N21 | 1.142 (5) | C34'—C35' | 1.490 (17) |
C22—C23 | 1.427 (5) | C35'—O' | 1.416 (17) |
C23—C24 | 1.367 (5) | C36'—O' | 1.416 (16) |
C24—C25 | 1.439 (5) | C36'—C37' | 1.541 (17) |
C25—C26 | 1.443 (5) | C39'—C40' | 1.505 (19) |
| | | |
N1—C2—C3 | 178.8 (4) | C26—C25—C24 | 117.9 (3) |
C2—C3—C4 | 115.8 (3) | C27—C26—C25 | 121.1 (3) |
C6—C3—C4 | 122.7 (3) | C26—C27—C22 | 121.3 (3) |
C6—C3—C2 | 121.5 (3) | N28—C29—C30 | 178.8 (5) |
N5—C4—C3 | 178.5 (4) | C25—C30—C31 | 122.6 (3) |
C3—C6—C7 | 121.5 (3) | C25—C30—C29 | 122.5 (3) |
C3—C6—C11 | 121.3 (3) | C31—C30—C29 | 114.9 (3) |
C7—C6—C11 | 117.2 (3) | N32—C31—C30 | 179.2 (5) |
C8—C7—C6 | 121.3 (3) | C38—N33—C37 | 113.3 (4) |
C7—C8—C9 | 121.5 (3) | C38—N33—C34 | 109.8 (4) |
C14—C9—C8 | 121.3 (3) | C37—N33—C34 | 106.4 (3) |
C14—C9—C10 | 121.7 (3) | C38—N33—C39 | 109.1 (4) |
C8—C9—C10 | 117.0 (3) | C37—N33—C39 | 109.7 (4) |
C11—C10—C9 | 122.1 (3) | C34—N33—C39 | 108.3 (3) |
C10—C11—C6 | 120.9 (3) | C35—C34—N33 | 113.4 (3) |
N12—C13—C14 | 178.9 (4) | O—C35—C34 | 109.8 (4) |
C9—C14—C15 | 121.8 (3) | O—C36—C37 | 111.0 (4) |
C9—C14—C13 | 120.5 (3) | N33—C37—C36 | 111.4 (4) |
C15—C14—C13 | 117.7 (3) | C40—C39—N33 | 115.8 (5) |
N16—C15—C14 | 179.3 (5) | C36—O—C35 | 111.3 (4) |
N17—C18—C19 | 179.0 (4) | C38'—N33'—C37' | 113.5 (13) |
C22—C19—C20 | 120.8 (3) | C38'—N33'—C34' | 110.4 (13) |
C22—C19—C18 | 121.7 (3) | C37'—N33'—C34' | 105.4 (10) |
C20—C19—C18 | 117.4 (3) | C38'—N33'—C39' | 109.3 (13) |
N21—C20—C19 | 178.0 (5) | C37'—N33'—C39' | 109.9 (13) |
C19—C22—C23 | 121.7 (3) | C34'—N33'—C39' | 108.3 (12) |
C19—C22—C27 | 120.4 (3) | C35'—C34'—N33' | 116.3 (13) |
C23—C22—C27 | 117.8 (3) | O'—C35'—C34' | 110.6 (14) |
C24—C23—C22 | 121.7 (3) | O'—C36'—C37' | 109.2 (14) |
C23—C24—C25 | 120.2 (3) | N33'—C37'—C36' | 109.1 (12) |
C30—C25—C26 | 121.1 (3) | C40'—C39'—N33' | 115.0 (17) |
C30—C25—C24 | 121.0 (3) | C36'—O'—C35' | 110.8 (14) |
| | | |
C37—N33—C34—C35 | 53.7 (5) | O—C36—C37—N33 | 57.7 (6) |
C38—N33—C34—C35 | −69.3 (5) | C34—N33—C39—C40 | 179.8 (5) |
C39—N33—C34—C35 | 171.6 (4) | C37—N33—C39—C40 | −64.4 (6) |
N33—C34—C35—O | −58.4 (6) | C38—N33—C39—C40 | 60.3 (7) |
C34—N33—C37—C36 | −52.4 (5) | C34—C35—O—C36 | 60.4 (6) |
C38—N33—C37—C36 | 68.4 (6) | C37—C36—O—C35 | −60.8 (6) |
C39—N33—C37—C36 | −169.3 (4) | | |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
C8—H8···N12i | 0.93 | 2.65 | 3.317 (5) | 129 |
C11—H11···N5ii | 0.93 | 2.68 | 3.359 (5) | 131 |
C24—H24···N28ii | 0.93 | 2.66 | 3.329 (6) | 130 |
C27—H27···N21i | 0.93 | 2.71 | 3.380 (5) | 130 |
C34—H34A···N32 | 0.97 | 2.53 | 3.402 (5) | 149 |
C34—H34B···N1iii | 0.97 | 2.81 | 3.742 (7) | 162 |
C38—H38C···N5ii | 0.96 | 2.73 | 3.395 (7) | 127 |
C38—H38B···N17iv | 0.96 | 2.68 | 3.267 (8) | 120 |
Symmetry codes: (i) x+1, y, z; (ii) x−1, y, z; (iii) x, y, z−1; (iv) x, y+1, z+1. |
(MEMTCNQ-LT) 1:2 Complex of
N-Ethyl-
N-methylmorpholine and
7,7,8,8-Tetracyano-
p-quinodimethane
top
Crystal data top
2C12H4N4·C7H16NO | F(000) = 281 |
Mr = 538.59 | Dx = 1.305 Mg m−3 |
Triclinic, P1 | Melting point: not measured K |
a = 7.773 (1) Å | Mo Kα radiation, λ = 0.71073 Å |
b = 15.315 (2) Å | Cell parameters from 12 reflections |
c = 6.8347 (9) Å | θ = 12.7–16.3° |
α = 113.249 (8)° | µ = 0.09 mm−1 |
β = 73.569 (9)° | T = 10 K |
γ = 111.796 (9)° | Prism, black |
V = 685.2 (2) Å3 | 0.55 × 0.45 × 0.25 mm |
Z = 1 | |
Data collection top
Huber 512 goniometer diffractometer | Rint = 0.011 |
Radiation source: normal-focus sealed tube | θmax = 30.1°, θmin = 1.5° |
None monochromator | h = −10→10 |
ω–2θ scan | k = −21→21 |
8048 measured reflections | l = −9→9 |
4024 independent reflections | 3 standard reflections every 100 reflections |
3966 reflections with I > 2σ(I) | intensity decay: 1% |
Refinement top
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.030 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.085 | w = 1/[σ2(Fo2) + (0.0698P)2 + 0.0427P] where P = (Fo2 + 2Fc2)/3 |
S = 1.03 | (Δ/σ)max < 0.001 |
4024 reflections | Δρmax = 0.44 e Å−3 |
467 parameters | Δρmin = −0.25 e Å−3 |
3 restraints | Extinction correction: SHELXL, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.046 (4) |
Crystal data top
2C12H4N4·C7H16NO | γ = 111.796 (9)° |
Mr = 538.59 | V = 685.2 (2) Å3 |
Triclinic, P1 | Z = 1 |
a = 7.773 (1) Å | Mo Kα radiation |
b = 15.315 (2) Å | µ = 0.09 mm−1 |
c = 6.8347 (9) Å | T = 10 K |
α = 113.249 (8)° | 0.55 × 0.45 × 0.25 mm |
β = 73.569 (9)° | |
Data collection top
Huber 512 goniometer diffractometer | Rint = 0.011 |
8048 measured reflections | 3 standard reflections every 100 reflections |
4024 independent reflections | intensity decay: 1% |
3966 reflections with I > 2σ(I) | |
Refinement top
R[F2 > 2σ(F2)] = 0.030 | 3 restraints |
wR(F2) = 0.085 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.03 | Δρmax = 0.44 e Å−3 |
4024 reflections | Δρmin = −0.25 e Å−3 |
467 parameters | |
Special details top
Experimental. The correction for the absorption by the beryllium thermal shields was performed
by PROFIT (Streltsov & Zavodnik, 1989) program. |
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes)
are estimated using the full covariance matrix. The cell e.s.d.'s are taken
into account individually in the estimation of e.s.d.'s in distances, angles
and torsion angles; correlations between e.s.d.'s in cell parameters are only
used when they are defined by crystal symmetry. An approximate (isotropic)
treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s.
planes. |
Refinement. Refinement of F2 against ALL reflections. The weighted R-factor
wR and goodness of fit S are based on F2, conventional
R-factors R are based on F, with F set to zero for
negative F2. The threshold expression of F2 >
σ(F2) is used only for calculating R-factors(gt) etc.
and is not relevant to the choice of reflections for refinement.
R-factors based on F2 are statistically about twice as large
as those based on F, and R- factors based on ALL data will be
even larger. |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
N1 | 0.30874 (16) | 0.43209 (8) | 0.36559 (18) | 0.0127 (2) | |
C2 | 0.33242 (16) | 0.35760 (9) | 0.33937 (19) | 0.0093 (2) | |
C3 | 0.35861 (16) | 0.26560 (8) | 0.30954 (18) | 0.0084 (2) | |
C4 | 0.54277 (18) | 0.26775 (9) | 0.3121 (2) | 0.0098 (2) | |
N5 | 0.69176 (16) | 0.26843 (9) | 0.3135 (2) | 0.0138 (2) | |
C6 | 0.20817 (15) | 0.17709 (9) | 0.28578 (18) | 0.0077 (2) | |
C7 | 0.23392 (16) | 0.08566 (9) | 0.26440 (18) | 0.0079 (2) | |
H7 | 0.357 (3) | 0.0788 (17) | 0.256 (4) | 0.020 (5)* | |
C8 | 0.08668 (16) | 0.00030 (9) | 0.24551 (18) | 0.0080 (2) | |
H8 | 0.103 (3) | −0.0645 (17) | 0.234 (4) | 0.019 (5)* | |
C9 | −0.09829 (16) | −0.00013 (8) | 0.24675 (18) | 0.0075 (2) | |
C10 | −0.12459 (16) | 0.09156 (9) | 0.26961 (19) | 0.0085 (2) | |
H10 | −0.252 (3) | 0.0925 (15) | 0.277 (3) | 0.015 (5)* | |
C11 | 0.02250 (16) | 0.17683 (9) | 0.28887 (18) | 0.0080 (2) | |
H11 | −0.002 (3) | 0.2381 (16) | 0.306 (4) | 0.017 (5)* | |
N12 | −0.58306 (16) | −0.08424 (8) | 0.23928 (19) | 0.0127 (2) | |
C13 | −0.43519 (17) | −0.08765 (9) | 0.2320 (2) | 0.0091 (2) | |
C14 | −0.24987 (16) | −0.08801 (9) | 0.22446 (18) | 0.0081 (2) | |
C15 | −0.22617 (16) | −0.17982 (9) | 0.20197 (19) | 0.0083 (2) | |
N16 | −0.20334 (15) | −0.25327 (8) | 0.18435 (17) | 0.0111 (2) | |
N17 | −0.31420 (15) | −0.43080 (8) | −0.35218 (18) | 0.0125 (2) | |
C18 | −0.33671 (16) | −0.35771 (9) | −0.33737 (19) | 0.0091 (2) | |
C19 | −0.36058 (15) | −0.26626 (8) | −0.31819 (18) | 0.0085 (2) | |
C20 | −0.54269 (18) | −0.26983 (9) | −0.3336 (2) | 0.0092 (2) | |
N21 | −0.68991 (16) | −0.27357 (8) | −0.35009 (18) | 0.0124 (2) | |
C22 | −0.21220 (16) | −0.17841 (8) | −0.28823 (18) | 0.0076 (2) | |
C23 | −0.23732 (16) | −0.08627 (9) | −0.26662 (18) | 0.0081 (2) | |
H23 | −0.364 (3) | −0.0870 (15) | −0.265 (3) | 0.010 (4)* | |
C24 | −0.09012 (16) | −0.00141 (9) | −0.24531 (19) | 0.0081 (2) | |
H24 | −0.106 (3) | 0.0613 (15) | −0.233 (3) | 0.013 (5)* | |
C25 | 0.09538 (16) | −0.00207 (8) | −0.24551 (18) | 0.0075 (2) | |
C26 | 0.11990 (16) | −0.09460 (9) | −0.26716 (18) | 0.0080 (2) | |
H26 | 0.242 (3) | −0.0971 (16) | −0.266 (3) | 0.013 (4)* | |
C27 | −0.02770 (16) | −0.17861 (9) | −0.28556 (19) | 0.0082 (2) | |
H27 | −0.012 (3) | −0.2416 (16) | −0.294 (3) | 0.014 (5)* | |
N28 | 0.58364 (16) | 0.08795 (9) | −0.2346 (2) | 0.0131 (2) | |
C29 | 0.43249 (17) | 0.08574 (9) | −0.22985 (19) | 0.0092 (2) | |
C30 | 0.24565 (16) | 0.08433 (9) | −0.22420 (18) | 0.0081 (2) | |
C31 | 0.22483 (17) | 0.17696 (9) | −0.20085 (19) | 0.0090 (2) | |
N32 | 0.20984 (16) | 0.25235 (8) | −0.18072 (18) | 0.0130 (2) | |
N33 | 0.04730 (14) | 0.49155 (7) | 0.00450 (16) | 0.00794 (17) | |
C34 | 0.25124 (16) | 0.49271 (8) | −0.04326 (19) | 0.00880 (19) | |
H34A | 0.249 (3) | 0.4339 (16) | −0.026 (3) | 0.019 (5)* | |
H34B | 0.292 (2) | 0.4876 (12) | −0.190 (3) | 0.005 (4)* | |
C35 | 0.37101 (16) | 0.58790 (9) | 0.09732 (19) | 0.0096 (2) | |
H35A | 0.495 (3) | 0.5864 (15) | 0.055 (3) | 0.014 (4)* | |
H35B | 0.331 (3) | 0.5934 (14) | 0.249 (3) | 0.012 (4)* | |
C36 | 0.17409 (16) | 0.67818 (9) | 0.1252 (2) | 0.0112 (2) | |
H36A | 0.177 (3) | 0.7347 (15) | 0.106 (3) | 0.011 (4)* | |
H36B | 0.133 (2) | 0.6874 (12) | 0.272 (3) | 0.004 (3)* | |
C37 | 0.04250 (15) | 0.58668 (8) | −0.0109 (2) | 0.0096 (2) | |
H37A | 0.080 (3) | 0.5815 (14) | −0.163 (3) | 0.011 (4)* | |
H37B | −0.085 (3) | 0.5889 (15) | 0.039 (3) | 0.015 (4)* | |
C38 | −0.04077 (17) | 0.48226 (10) | 0.22377 (19) | 0.0127 (2) | |
H38A | 0.029 (3) | 0.5377 (15) | 0.334 (3) | 0.012 (4)* | |
H38B | −0.166 (3) | 0.4861 (14) | 0.259 (3) | 0.012 (4)* | |
H38C | −0.041 (3) | 0.4176 (16) | 0.224 (4) | 0.020 (5)* | |
C39 | −0.05429 (16) | 0.40143 (9) | −0.16591 (19) | 0.0105 (2) | |
H39A | 0.010 (3) | 0.4110 (14) | −0.297 (3) | 0.016 (4)* | |
H39B | −0.032 (3) | 0.3455 (16) | −0.156 (3) | 0.020 (5)* | |
C40 | −0.26213 (17) | 0.38751 (10) | −0.1427 (2) | 0.0130 (2) | |
H40A | −0.286 (3) | 0.4457 (18) | −0.149 (4) | 0.027 (6)* | |
H40B | −0.306 (3) | 0.3302 (17) | −0.253 (4) | 0.026 (5)* | |
H40C | −0.324 (3) | 0.3816 (17) | −0.010 (4) | 0.023 (5)* | |
O | 0.36237 (12) | 0.67293 (6) | 0.06469 (14) | 0.01027 (17) | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
N1 | 0.0115 (5) | 0.0127 (5) | 0.0147 (5) | 0.0033 (4) | −0.0037 (4) | 0.0045 (4) |
C2 | 0.0069 (5) | 0.0113 (5) | 0.0101 (5) | 0.0018 (4) | −0.0031 (4) | 0.0035 (4) |
C3 | 0.0072 (5) | 0.0091 (5) | 0.0106 (5) | 0.0026 (4) | −0.0029 (4) | 0.0036 (4) |
C4 | 0.0085 (5) | 0.0090 (5) | 0.0119 (5) | 0.0015 (4) | −0.0030 (4) | 0.0035 (4) |
N5 | 0.0099 (5) | 0.0126 (5) | 0.0205 (5) | 0.0025 (4) | −0.0048 (4) | 0.0060 (4) |
C6 | 0.0060 (5) | 0.0096 (5) | 0.0085 (5) | 0.0024 (4) | −0.0019 (4) | 0.0033 (4) |
C7 | 0.0064 (5) | 0.0097 (5) | 0.0091 (5) | 0.0029 (4) | −0.0025 (4) | 0.0032 (4) |
C8 | 0.0064 (5) | 0.0095 (5) | 0.0092 (5) | 0.0027 (4) | −0.0026 (4) | 0.0028 (4) |
C9 | 0.0068 (5) | 0.0087 (5) | 0.0082 (5) | 0.0030 (4) | −0.0018 (4) | 0.0028 (4) |
C10 | 0.0076 (5) | 0.0084 (5) | 0.0104 (5) | 0.0029 (4) | −0.0028 (4) | 0.0028 (4) |
C11 | 0.0062 (5) | 0.0083 (5) | 0.0101 (5) | 0.0024 (4) | −0.0021 (4) | 0.0028 (4) |
N12 | 0.0103 (5) | 0.0107 (5) | 0.0183 (5) | 0.0032 (4) | −0.0036 (4) | 0.0048 (4) |
C13 | 0.0089 (5) | 0.0074 (5) | 0.0113 (5) | 0.0018 (4) | −0.0022 (4) | 0.0034 (4) |
C14 | 0.0061 (5) | 0.0095 (5) | 0.0096 (5) | 0.0023 (4) | −0.0021 (4) | 0.0035 (4) |
C15 | 0.0062 (5) | 0.0104 (5) | 0.0087 (5) | 0.0016 (4) | −0.0025 (4) | 0.0033 (4) |
N16 | 0.0093 (5) | 0.0119 (5) | 0.0138 (5) | 0.0037 (4) | −0.0034 (4) | 0.0043 (4) |
N17 | 0.0115 (5) | 0.0119 (5) | 0.0149 (5) | 0.0047 (4) | −0.0019 (4) | 0.0041 (4) |
C18 | 0.0059 (5) | 0.0104 (5) | 0.0097 (5) | 0.0008 (4) | −0.0023 (4) | 0.0027 (4) |
C19 | 0.0058 (5) | 0.0100 (5) | 0.0100 (5) | 0.0023 (4) | −0.0020 (4) | 0.0032 (4) |
C20 | 0.0099 (5) | 0.0081 (5) | 0.0103 (5) | 0.0030 (4) | −0.0028 (4) | 0.0028 (4) |
N21 | 0.0105 (5) | 0.0134 (5) | 0.0142 (5) | 0.0041 (4) | −0.0036 (4) | 0.0038 (4) |
C22 | 0.0069 (5) | 0.0087 (5) | 0.0081 (5) | 0.0031 (4) | −0.0019 (4) | 0.0023 (4) |
C23 | 0.0072 (5) | 0.0088 (5) | 0.0095 (5) | 0.0028 (4) | −0.0022 (4) | 0.0032 (4) |
C24 | 0.0073 (5) | 0.0094 (5) | 0.0093 (5) | 0.0034 (4) | −0.0018 (4) | 0.0035 (4) |
C25 | 0.0064 (5) | 0.0095 (5) | 0.0077 (5) | 0.0028 (4) | −0.0018 (4) | 0.0031 (4) |
C26 | 0.0064 (5) | 0.0091 (5) | 0.0097 (5) | 0.0029 (4) | −0.0022 (4) | 0.0031 (4) |
C27 | 0.0065 (5) | 0.0097 (5) | 0.0098 (5) | 0.0030 (4) | −0.0024 (4) | 0.0031 (4) |
N28 | 0.0100 (5) | 0.0136 (5) | 0.0172 (5) | 0.0041 (4) | −0.0034 (4) | 0.0051 (4) |
C29 | 0.0091 (5) | 0.0088 (5) | 0.0099 (5) | 0.0023 (4) | −0.0019 (4) | 0.0032 (4) |
C30 | 0.0072 (5) | 0.0085 (5) | 0.0097 (5) | 0.0029 (4) | −0.0020 (4) | 0.0033 (4) |
C31 | 0.0070 (5) | 0.0107 (5) | 0.0098 (5) | 0.0026 (4) | −0.0024 (4) | 0.0032 (4) |
N32 | 0.0136 (5) | 0.0125 (5) | 0.0149 (5) | 0.0050 (4) | −0.0034 (4) | 0.0045 (4) |
N33 | 0.0069 (4) | 0.0076 (4) | 0.0098 (4) | 0.0022 (3) | −0.0018 (3) | 0.0030 (3) |
C34 | 0.0063 (4) | 0.0089 (4) | 0.0118 (5) | 0.0029 (3) | −0.0021 (4) | 0.0028 (4) |
C35 | 0.0087 (5) | 0.0085 (4) | 0.0121 (5) | 0.0024 (4) | −0.0037 (4) | 0.0027 (4) |
C36 | 0.0083 (5) | 0.0082 (5) | 0.0164 (5) | 0.0032 (4) | −0.0029 (4) | 0.0019 (4) |
C37 | 0.0082 (5) | 0.0071 (4) | 0.0158 (5) | 0.0026 (4) | −0.0034 (4) | 0.0046 (4) |
C38 | 0.0106 (5) | 0.0163 (5) | 0.0101 (5) | 0.0019 (4) | −0.0008 (4) | 0.0057 (4) |
C39 | 0.0089 (5) | 0.0091 (5) | 0.0123 (5) | 0.0017 (4) | −0.0050 (4) | 0.0009 (4) |
C40 | 0.0079 (5) | 0.0155 (5) | 0.0156 (5) | 0.0020 (4) | −0.0046 (4) | 0.0047 (4) |
O | 0.0077 (3) | 0.0092 (4) | 0.0153 (4) | 0.0027 (3) | −0.0023 (3) | 0.0050 (3) |
Geometric parameters (Å, º) top
N1—C2 | 1.159 (2) | C27—C22 | 1.441 (2) |
C2—C3 | 1.425 (2) | C27—H27 | 0.99 (2) |
C3—C4 | 1.424 (2) | N28—C29 | 1.154 (2) |
C3—C6 | 1.410 (2) | C29—C30 | 1.434 (2) |
C4—N5 | 1.157 (2) | C30—C25 | 1.390 (2) |
C6—C7 | 1.433 (2) | C30—C31 | 1.429 (2) |
C7—C8 | 1.369 (2) | C31—N32 | 1.154 (2) |
C7—H7 | 0.99 (2) | N33—C34 | 1.520 (1) |
C8—C9 | 1.433 (2) | N33—C37 | 1.516 (1) |
C8—H8 | 1.02 (2) | N33—C38 | 1.500 (2) |
C9—C10 | 1.435 (2) | N33—C39 | 1.525 (1) |
C10—C11 | 1.368 (2) | C34—C35 | 1.519 (2) |
C10—H10 | 0.98 (2) | C34—H34A | 0.95 (2) |
C11—C6 | 1.436 (2) | C34—H34B | 0.94 (2) |
C11—H11 | 0.98 (2) | C35—O | 1.433 (1) |
N12—C13 | 1.156 (2) | C35—H35A | 0.93 (2) |
C13—C14 | 1.429 (2) | C35—H35B | 0.98 (2) |
C14—C9 | 1.409 (2) | C36—O | 1.428 (1) |
C14—C15 | 1.428 (2) | C36—C37 | 1.523 (2) |
C15—N16 | 1.158 (2) | C36—H36A | 0.92 (2) |
N17—C18 | 1.158 (2) | C36—H36B | 0.93 (2) |
C18—C19 | 1.431 (2) | C37—H37A | 0.98 (2) |
C19—C20 | 1.428 (2) | C37—H37B | 0.96 (2) |
C19—C22 | 1.395 (2) | C38—H38A | 0.98 (2) |
C20—N21 | 1.160 (2) | C38—H38B | 0.95 (2) |
C22—C23 | 1.441 (2) | C38—H38C | 0.99 (2) |
C23—C24 | 1.364 (2) | C39—C40 | 1.519 (2) |
C23—H23 | 0.98 (2) | C39—H39A | 0.93 (2) |
C24—C25 | 1.445 (2) | C39—H39B | 0.96 (2) |
C24—H24 | 0.98 (2) | C40—H40A | 0.99 (2) |
C25—C26 | 1.444 (2) | C40—H40B | 0.92 (2) |
C26—C27 | 1.358 (2) | C40—H40C | 0.92 (2) |
C26—H26 | 0.96 (2) | | |
| | | |
N1—C2—C3 | 179.0 (1) | C25—C30—C29 | 122.2 (1) |
C2—C3—C4 | 116.9 (1) | C31—C30—C29 | 115.6 (1) |
C6—C3—C4 | 121.4 (1) | N32—C31—C30 | 179.2 (1) |
C6—C3—C2 | 121.7 (1) | C38—N33—C37 | 111.5 (1) |
N5—C4—C3 | 179.3 (1) | C38—N33—C34 | 110.1 (1) |
C3—C6—C7 | 121.4 (1) | C37—N33—C34 | 108.0 (1) |
C3—C6—C11 | 120.6 (1) | C38—N33—C39 | 109.4 (1) |
C7—C6—C11 | 118.0 (1) | C37—N33—C39 | 110.3 (1) |
C8—C7—C6 | 121.2 (1) | C34—N33—C39 | 107.5 (1) |
C8—C7—H7 | 115.6 (13) | C35—C34—N33 | 111.6 (1) |
C6—C7—H7 | 123.2 (13) | C35—C34—H34A | 114.6 (13) |
C7—C8—C9 | 120.9 (11) | N33—C34—H34A | 105.4 (13) |
C7—C8—H8 | 121.7 (13) | C35—C34—H34B | 110.3 (10) |
C9—C8—H8 | 117.5 (13) | N33—C34—H34B | 105.8 (10) |
C14—C9—C8 | 121.1 (1) | H34A—C34—H34B | 108.6 (16) |
C14—C9—C10 | 120.8 (1) | O—C35—C34 | 110.6 (1) |
C8—C9—C10 | 118.0 (1) | O—C35—H35A | 107.7 (12) |
C11—C10—C9 | 121.1 (1) | C34—C35—H35A | 107.8 (12) |
C11—C10—H10 | 120.4 (12) | O—C35—H35B | 109.9 (11) |
C9—C10—H10 | 118.5 (12) | C34—C35—H35B | 111.0 (11) |
C10—C11—C6 | 120.9 (1) | H35A—C35—H35B | 109.8 (17) |
C10—C11—H11 | 118.5 (13) | O—C36—C37 | 111.4 (1) |
C6—C11—H11 | 120.6 (13) | O—C36—H36A | 106.5 (12) |
N12—C13—C14 | 177.9 (1) | C37—C36—H36A | 110.9 (12) |
C9—C14—C15 | 121.5 (1) | O—C36—H36B | 110.9 (11) |
C9—C14—C13 | 121.0 (1) | C37—C36—H36B | 111.3 (11) |
C15—C14—C13 | 117.4 (1) | H36A—C36—H36B | 105.6 (16) |
N16—C15—C14 | 178.7 (1) | N33—C37—C36 | 111.7 (1) |
N17—C18—C19 | 178.8 (1) | N33—C37—H37A | 106.4 (11) |
C22—C19—C20 | 121.9 (1) | C36—C37—H37A | 110.4 (11) |
C22—C19—C18 | 121.4 (1) | N33—C37—H37B | 106.7 (12) |
C20—C19—C18 | 116.7 (1) | C36—C37—H37B | 110.4 (12) |
N21—C20—C19 | 178.8 (1) | H37A—C37—H37B | 111.1 (17) |
C19—C22—C23 | 121.2 (1) | N33—C38—H38A | 110.0 (11) |
C19—C22—C27 | 120.4 (1) | N33—C38—H38B | 110.5 (11) |
C23—C22—C27 | 118.3 (1) | H38A—C38—H38B | 106.7 (16) |
C24—C23—C22 | 120.9 (1) | N33—C38—H38C | 108.8 (13) |
C24—C23—H23 | 121.7 (12) | H38A—C38—H38C | 111.0 (17) |
C22—C23—H23 | 117.3 (11) | H38B—C38—H38C | 109.8 (17) |
C23—C24—C25 | 120.7 (1) | C40—C39—N33 | 115.0 (1) |
C23—C24—H24 | 121.1 (12) | C40—C39—H39A | 111.1 (12) |
C25—C24—H24 | 118.2 (12) | N33—C39—H39A | 104.6 (12) |
C30—C25—C26 | 121.0 (1) | C40—C39—H39B | 112.2 (13) |
C30—C25—C24 | 120.7 (1) | N33—C39—H39B | 104.8 (13) |
C26—C25—C24 | 118.2 (1) | H39A—C39—H39B | 108.7 (17) |
C27—C26—C25 | 120.9 (1) | C39—C40—H40A | 112.5 (14) |
C27—C26—H26 | 119.0 (13) | C39—C40—H40B | 105.8 (15) |
C25—C26—H26 | 120.1 (12) | H40A—C40—H40B | 112 (2) |
C26—C27—C22 | 121.0 (1) | C39—C40—H40C | 110.7 (14) |
C26—C27—H27 | 120.9 (13) | H40A—C40—H40C | 105.1 (19) |
C22—C27—H27 | 118.1 (13) | H40B—C40—H40C | 111 (2) |
N28—C29—C30 | 179.2 (1) | C36—O—C35 | 110.0 (1) |
C25—C30—C31 | 122.1 (1) | | |
| | | |
C37—N33—C34—C35 | 52.6 (1) | O—C36—C37—N33 | 57.1 (1) |
C38—N33—C34—C35 | −69.3 (1) | C34—N33—C39—C40 | 179.5 (1) |
C39—N33—C34—C35 | 171.6 (1) | C37—N33—C39—C40 | −63.0 (1) |
N33—C34—C35—O | −58.8 (1) | C38—N33—C39—C40 | 60.0 (1) |
C34—N33—C37—C36 | −51.6 (1) | C34—C35—O—C36 | 61.8 (1) |
C38—N33—C37—C36 | 69.5 (1) | C37—C36—O—C35 | −61.1 (1) |
C39—N33—C37—C36 | −168.8 (1) | | |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
C8—H8···N12i | 1.02 (2) | 2.58 (2) | 3.261 (2) | 124.2 (16) |
C11—H11···N5ii | 0.98 (2) | 2.57 (2) | 3.294 (2) | 130.3 (17) |
C24—H24···N28ii | 0.98 (2) | 2.59 (2) | 3.271 (2) | 126.3 (15) |
C27—H27···N21i | 0.99 (2) | 2.62 (2) | 3.298 (2) | 125.3 (16) |
C34—H34A···N32 | 0.95 (2) | 2.49 (2) | 3.331 (2) | 149.0 (17) |
C34—H34B···N1iii | 0.94 (2) | 2.79 (2) | 3.703 (2) | 163.1 (14) |
C38—H38C···N5ii | 0.99 (2) | 2.60 (2) | 3.351 (2) | 132.6 (17) |
C38—H38B···N17iv | 0.95 (2) | 2.59 (2) | 3.203 (2) | 122.6 (14) |
Symmetry codes: (i) x+1, y, z; (ii) x−1, y, z; (iii) x, y, z−1; (iv) x, y+1, z+1. |
Experimental details
| (MEMTCNQ-RT) | (MEMTCNQ-LT) |
Crystal data |
Chemical formula | 2C12H4N4·C7H16NO | 2C12H4N4·C7H16NO |
Mr | 538.59 | 538.59 |
Crystal system, space group | Triclinic, P1 | Triclinic, P1 |
Temperature (K) | 293 | 10 |
a, b, c (Å) | 7.803 (1), 15.353 (2), 6.985 (1) | 7.773 (1), 15.315 (2), 6.8347 (9) |
α, β, γ (°) | 112.30 (1), 74.44 (1), 111.84 (1) | 113.249 (8), 73.569 (9), 111.796 (9) |
V (Å3) | 710.7 (2) | 685.2 (2) |
Z | 1 | 1 |
Radiation type | Mo Kα | Mo Kα |
µ (mm−1) | 0.08 | 0.09 |
Crystal size (mm) | 0.55 × 0.45 × 0.25 | 0.55 × 0.45 × 0.25 |
|
Data collection |
Diffractometer | Huber 512 goniometer diffractometer | Huber 512 goniometer diffractometer |
Absorption correction | – | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 4110, 4110, 2851 | 8048, 4024, 3966 |
Rint | 0.000 | 0.011 |
(sin θ/λ)max (Å−1) | 0.705 | 0.705 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.049, 0.158, 1.04 | 0.030, 0.085, 1.03 |
No. of reflections | 4110 | 4024 |
No. of parameters | 408 | 467 |
No. of restraints | 24 | 3 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.23, −0.15 | 0.44, −0.25 |
Hydrogen-bond geometry (Å, º) for (MEMTCNQ-RT) top
D—H···A | D—H | H···A | D···A | D—H···A |
C8—H8···N12i | 0.93 | 2.65 | 3.317 (5) | 128.8 |
C11—H11···N5ii | 0.93 | 2.68 | 3.359 (5) | 130.7 |
C24—H24···N28ii | 0.93 | 2.66 | 3.329 (6) | 129.7 |
C27—H27···N21i | 0.93 | 2.71 | 3.380 (5) | 129.7 |
C34—H34A···N32 | 0.97 | 2.53 | 3.402 (5) | 149.2 |
C34—H34B···N1iii | 0.97 | 2.81 | 3.742 (7) | 161.7 |
C38—H38C···N5ii | 0.96 | 2.73 | 3.395 (7) | 127.2 |
C38—H38B···N17iv | 0.96 | 2.68 | 3.267 (8) | 120.1 |
Symmetry codes: (i) x+1, y, z; (ii) x−1, y, z; (iii) x, y, z−1; (iv) x, y+1, z+1. |
Hydrogen-bond geometry (Å, º) for (MEMTCNQ-LT) top
D—H···A | D—H | H···A | D···A | D—H···A |
C8—H8···N12i | 1.02 (2) | 2.58 (2) | 3.261 (2) | 124.2 (16) |
C11—H11···N5ii | 0.98 (2) | 2.57 (2) | 3.294 (2) | 130.3 (17) |
C24—H24···N28ii | 0.98 (2) | 2.59 (2) | 3.271 (2) | 126.3 (15) |
C27—H27···N21i | 0.99 (2) | 2.62 (2) | 3.298 (2) | 125.3 (16) |
C34—H34A···N32 | 0.95 (2) | 2.49 (2) | 3.331 (2) | 149.0 (17) |
C34—H34B···N1iii | 0.94 (2) | 2.79 (2) | 3.703 (2) | 163.1 (14) |
C38—H38C···N5ii | 0.99 (2) | 2.60 (2) | 3.351 (2) | 132.6 (17) |
C38—H38B···N17iv | 0.95 (2) | 2.59 (2) | 3.203 (2) | 122.6 (14) |
Symmetry codes: (i) x+1, y, z; (ii) x−1, y, z; (iii) x, y, z−1; (iv) x, y+1, z+1. |
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The charge transfer salt morpholinium tetracyanoquinonate [MEM(TCNQ)2] undergoes a first order structural phase transition at 340 K (Tc) with dimerization of one-dimensional stacks of TCNQ units and a ca 1000-fold decrease in electrical conductivity (van Bodegom, 1981; van Bodegom & Bosch, 1981). There is also a transition of second order at 19 K (TsP) associated with the electronically driven spin-Peierls dimerization of the antiferromagnetic Heisenberg spin-1/2 chain of [(TCNQ)2]- dimers (van Bodegom, 1981; Larson & Mook, 1995). \sch
The main structural changes in MEM(TCNQ)2 at 340 K are related to the disorder of the MEM group through merohedral twinning, which causes a subtle dimerization of the TCNQ stacks. The degree of twinning is related to disorder of the MEM group around a local pseudo inversion centre (0;1/2;0 for the set of coordinates used here) which changes with temperature. With the assumption of two preferred orientations, the 100% occupancy of the MEM orientation observed at 113 K (Bosch & van Bodegom, 1977), decreases to 84% at 294 K, 63% at 323 K, and reaches 50% above the high-temperature phase transition at Tc. A low-temperature crystallographic study has recently determined the dynamics of the c-doubling spin-Peierls transition (Lumsden & Gaulin, 1999), although structural data have yet to be collected below TsP.
We present here results of an X-ray study of the compound at room temperature followed by one on the same crystal at 10 K. We undertook the low-temperature investigation with the aim of obtaining data for structural refinement of the spin-Peierls ground state, which would give information unique for a spin-Peierls system. At 10 K, however, we were unable to observe evidence for the doubling of the c axis associated with spin-Peierls dimerization.
A previous study on the same crystal used here, performed at 15 K on diffractometer ID11 at the European Synchrotron Radiation Facility, had been successful in locating discrete weak c*/2 superstructure reflections associated with the spin-Peierls dimerization. Integration of image plate data confirmed the existence of the c*/2 modulation, whose superstructure reflection intensities were 10-3 to 10-4 of those of neighbouring Bragg reflections (Kepert et al., 1999) Also, a magnetic study of fresh crystals from the same synthetic batch was successful in showing the presence of the spin-Peierls transition (Lovett et al., 2000).
The room-temperature structure of MEM(TCNQ)2 has been discussed in detail earlier (van Bodegom, 1981) and our data are somewhat more accurate. The general view of the compound with its atom numbering scheme, as used by Bosch & van Bodegom (1977) for their 113 K structure, is given in Figure 1. The structure of the compound in the crystal consists of TCNQ columns stacked along the c direction with MEM molecules between them. The geometrical characteristics found for our models are close to those in the final model of the 113 K structure of Bosch & van Bodegom (1977). The shortest CH···N separations between successive TCNQ columns and their nearest neighbour MEM molecules are listed in the tables of hydrogen bonds. The value obtained for the MEM site population parameter x, 0.835 (5), is in very good coincidence with 0.84 reported by van Bodegom (1981).
In the molecule of TCNQ there are five different kinds of non-hydrogen bonds; two endocyclic bonds Csp2═Csp2 1.352 (10) and Csp2—Csp2 1.432 (12) Å and three exocyclic bonds Csp2═Csp2 1.392 (17), Csp2—Csp1 1.427 (10) and Csp1═N 1.144 (8) Å. The bond lengths given here are averaged distances taken from the Cambridge Crystallographic Data Base (Allen et al., 1979) and published in International Tables for Crystallography, Vol. C, Table 9.5.1.1. They form the series of bonds; C7—C8, C6—C7, C3—C6, C2—C3 and N1—C2 (Fig 1). The averaged results for our room-temperature structures are 1.355 (8), 1.436 (6), 1.397 (7), 1.426 (7) and 1.144 (7) Å, respectively, and are in excellent coincidence with preceding literature data. The 10 K averaged results, 1.365 (4), 1.435 (5), 1.401 (8), 1.429 (3) and 1.157 (2) Å, are slightly different from those published for the 113 K structure [Bosch & van Bodegom, 1977; 1.359 (3), 1.446 (3), 1.392 (7), 1.439 (3) and 1.160 (4) Å], but may be considered normal within a 3σ limit. The C—H bond lengths vary from 0.92 to 1.02 Å and give the average value 0.97 (2) Å. The dihedral angle between the best least-squares planes of the quinodimethane groups for the room-temperature and 10 K structures are 1.06 (6) and 1.81 (1)°. The dihedral angles between benzene rings and cyanide groups are 3.1 (1) and 3.15 (3)° (N1 -> N5 cyanide), 1.4 (1) and 1.70 (3)° (N12 -> N16 cyanide) for molecule 1 of TCNQ; 4.1 (1) and 4.29 (3)° (N17 -> N(21) cyanide), 2.5 (1) and 1.79 (3)° (N28 -> N32 cyanide) for molecule 2. The interatomic distances in the MEM molecule correspond to normal values and the ring is in the chair conformation.
In our experiment at 10 K we were not able to detect the results of the spin-Peierls transition. It is possible that radiation damage arising from the earlier synchrotron study has led to a lowering of TsP for the crystal studied. Such a lowering, which is well established for electronic transitions in one-dimensional electronic materials (Zuppiroli, 1988), arises from the inhibition of three-dimensional long range ordering in the presence of radiation-induced defect sites. Although weak diffuse scattering is anticipated in such cases, the series of scans we performed along the c* direction of reciprocal space showed no detectable systematic features above the background. It is possible that our equipment was not sufficiently sensitive to detect peaks as small as 10-3 of the nearby Bragg intensities in the presence of the noise from powder scattering from the Be thermal shields.