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Low-temperature studies of the simple variously substituted imidazole types 4-phenyl-1H-imidazole, C9H8N2, 1-benzyl-1H-imidazole, C10H10N2, and 1-mesityl-1H-imidazole, C12H14N2, extend comparisons between parent imidazole species and their derivatives, the pronounced double-bond localization opposite the substituted N atom common to simple neutral species being redistributed aromatically on protonation.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270104013228/ta1452sup1.cif
Contains datablocks global, I, II, III

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270104013228/ta1452Isup2.hkl
Contains datablock I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270104013228/ta1452IIsup3.hkl
Contains datablock II

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270104013228/ta1452IIIsup4.hkl
Contains datablock III

CCDC references: 248143; 248144; 248145

Comment top

The wide relevance of imidazole, imH, and derivative systems in biological arrays, mono- and oligo-dentate ligand coordination complexes, and catalytically relevant carbenes has led to experimental and theoretical studies of electron distributions therein (e.g. Hsu & Schlemper, 1980; Arduengo et al., 1972). Many structural data are available, some of the more recent of good precision, but interspecies comparisons and studies of associated structural progressions and evolutions among simple species are relatively sparse. The present study of the title compounds, (I), (II) and (III), respectively, comprises additional contributions to the known data; in each case, one molecule, with H-atom positions well defined, comprises the asymmetric unit of the structure. Selected geometric parameters for the non-H atoms are presented in Tables 1–3, and the individual molecules are depicted, normal to their C3N2 im planes, in Figs. 1–3.

Recently, an independent study of (I) was published by Claramunt et al. (2002); although the temperature of the experiment is not cited in the paper, it would appear from the cell volume and CCDC deposition to have been executed at room temperature. The present determination at a lower temperature offers a more extensive data set, with s.u. values for the bond lengths of the ring reduced generally by a factor of 3. The hydrogen associations and hydrogen-bonding linking successive molecules in a spiral about the major axis are essentially as described and depicted in the earlier report, but the differences in the geometric parameters are substantial and significant.

Table 4 presents the geometric parameters of all of the im rings presented comparatively, together with those of related structures. Although these structure determinations are variable in precision and temperature of execution, a number of useful general comments are possible. The geometric parameters within the im rings of the neutral molecules are generally similar, regardless of replacement of the imine H atom by other substituents or the presence of substituents at other sites in the ring. In respect of the latter, it appears to be widespread that, because of steric and/or electronic and/or lattice force imperatives, the imine H atom tends to lie `trans' to any substituent at atoms C4 or C5, so that sites 1 and 4 tend to be occupied, as is the case in (I). Given that disposition, bond b is short, as is bond d (relative to typical aromatic N—C and C—C bonds), with angles β and γ correspondingly enlarged. With protonation of the second ring N atom, the imH2+ array becomes more symmetrical, approximating mm symmetry, with bonding parameters more evenly aromatic and little altered on passing from imH2+ to the imMe2+ species that are recorded with comparable precision. A system of particular interest in this context is the 4-(2-NH2—C6H4) imH array. In this species, the NH2 substituent of the phenyl ring lies adjacent to the unprotonated imH N atom [N···H = 2.11 (4) Å], incipiently protonating it. The torsion angle about the bond between the two rings is −50.3 (6)°, and there is a considerable exocyclic asymmetry at the substituted im C atom [121.2 (4), cf. 129.4 (4)°], the smaller angle being? enclosed by the NH2 substituent. This situation parallels the substituent disposition in (I) (Table 1), where the equivalent torsion angle is −38.6 (2)°. The difference between the pendant N—C(substituent) bond lengths in (II) and (III) is substantial and interesting, reflecting the differences in the electronic characteristics of benzyl and mesityl. The dihedral angle between the two aromatic planes in (III) is 73.7 (1)°.

Experimental top

Crystals were obtained by recrystallization from CH2Cl2 [for (I) and (II)] and methanol [for (III)].

Refinement top

H atoms were located from difference Fourier maps, and were then placed at idealized positions [C—H = 0.95 Å and Uiso(H) = 1.5Ueq(C)]. All H-atom parameters were refined for (I) and (II) [C—H = 0.96 (2)–0.99 (2) Å and N—H = 85 (2) Å for (I), and C—H = 0.947 (18)–1.01 (2) Å for (II)] and fixed for (III) [C—H = 0.939–0.968 Å].

Computing details top

For all compounds, data collection: SMART (Siemens, 1995); cell refinement: SAINT (Siemens, 1995); data reduction: SAINT; program(s) used to solve structure: Xtal3.5 (Hall et al., 1995). Program(s) used to refine structure: CRYLSQ in Xtal3.5 for (I), (III); CRYLSQin Xtal3.5 for (II). For all compounds, molecular graphics: Xtal3.5; software used to prepare material for publication: BONDLA and CIFIO in Xtal3.5.

Figures top
[Figure 1] Fig. 1. A molecular projection of (I). Displacement ellipsoids are drawn at the 50% probability level and H atoms are shown with an arbitrary radius of 0.1 Å.
[Figure 2] Fig. 2. A molecular projection of (II). Displacement ellipsoids are drawn at the 50% probability level and H atoms are shown with an arbitrary radius of 0.1 Å.
[Figure 3] Fig. 3. A molecular projection of (III). Displacement ellipsoids are drawn at the 50% probability level and H atoms are shown with an arbitrary radius of 0.1 Å.
(I) top
Crystal data top
C9H8N2Dx = 1.221 Mg m3
Mr = 144.19Mo Kα radiation, λ = 0.71073 Å
Trigonal, R3cCell parameters from 8192 reflections
Hall symbol: r 3 -2"cθ = 2.4–28.6°
a = 20.449 (2) ŵ = 0.08 mm1
c = 9.750 (1) ÅT = 150 K
V = 3530.9 (6) Å3Slab, colourless
Z = 180.4 × 0.35 × 0.14 mm
F(000) = 1368
Data collection top
Bruker SMART CCD
diffractometer
1043 independent reflections
Radiation source: sealed tube1022 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.026
ω scansθmax = 29.0°, θmin = 2.0°
Absorption correction: multi-scan
SADABS; Sheldrick, 1996
h = 2727
Tmin = 0.920, Tmax = 0.951k = 2727
13318 measured reflectionsl = 1212
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.028Hydrogen site location: difference Fourier map
wR(F2) = 0.056All H-atom parameters refined
S = 1.08 w = 1/(σ2(F) + 0.42F2)
1043 reflections(Δ/σ)max = 0.001
131 parametersΔρmax = 0.16 e Å3
0 restraintsΔρmin = 0.16 e Å3
0 constraints
Crystal data top
C9H8N2Z = 18
Mr = 144.19Mo Kα radiation
Trigonal, R3cµ = 0.08 mm1
a = 20.449 (2) ÅT = 150 K
c = 9.750 (1) Å0.4 × 0.35 × 0.14 mm
V = 3530.9 (6) Å3
Data collection top
Bruker SMART CCD
diffractometer
1043 independent reflections
Absorption correction: multi-scan
SADABS; Sheldrick, 1996
1022 reflections with I > 2σ(I)
Tmin = 0.920, Tmax = 0.951Rint = 0.026
13318 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0280 restraints
wR(F2) = 0.056All H-atom parameters refined
S = 1.08Δρmax = 0.16 e Å3
1043 reflectionsΔρmin = 0.16 e Å3
131 parameters
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
N10.20838 (8)0.57865 (8)0.2272 (2)0.0214 (6)
C20.21803 (9)0.61947 (9)0.1123 (2)0.0216 (6)
N30.20131 (8)0.57734 (8)0.00019 (18)0.0197 (5)
C40.17954 (9)0.50504 (9)0.0466 (2)0.0181 (6)
C410.15243 (9)0.43975 (9)0.0462 (2)0.0193 (6)
C420.17077 (11)0.38348 (10)0.0201 (2)0.0257 (7)
C430.14195 (12)0.31957 (11)0.1028 (2)0.0323 (8)
C440.09480 (12)0.31120 (11)0.2122 (2)0.0318 (8)
C450.07704 (11)0.36714 (11)0.2396 (2)0.0290 (7)
C460.10591 (10)0.43139 (10)0.1577 (2)0.0233 (7)
C50.18390 (9)0.50553 (9)0.1872 (2)0.0201 (6)
H10.2113 (13)0.5944 (13)0.309 (2)0.033 (6)*
H20.2330 (11)0.6726 (12)0.113 (2)0.028 (5)*
H50.1745 (13)0.4648 (14)0.249 (3)0.035 (6)*
H420.2025 (14)0.3892 (14)0.056 (2)0.034 (6)*
H430.1563 (14)0.2813 (14)0.085 (2)0.040 (6)*
H440.0754 (13)0.2663 (15)0.270 (2)0.038 (6)*
H450.0420 (14)0.3617 (14)0.314 (3)0.043 (7)*
H460.0919 (13)0.4699 (12)0.177 (2)0.027 (5)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0232 (7)0.0241 (7)0.0159 (6)0.0112 (6)0.0003 (5)0.0018 (5)
C20.0225 (8)0.0216 (7)0.0204 (6)0.0108 (6)0.0004 (6)0.0004 (6)
N30.0223 (6)0.0196 (6)0.0167 (6)0.0101 (6)0.0000 (5)0.0003 (5)
C40.0174 (7)0.0194 (7)0.0178 (7)0.0094 (6)0.0000 (5)0.0002 (6)
C410.0210 (7)0.0184 (7)0.0172 (7)0.0089 (6)0.0030 (6)0.0006 (6)
C420.0319 (9)0.0258 (8)0.0238 (8)0.0176 (7)0.0010 (7)0.0002 (6)
C430.0444 (11)0.0242 (9)0.0324 (10)0.0201 (9)0.0036 (8)0.0000 (7)
C440.0411 (11)0.0234 (8)0.0250 (8)0.0116 (8)0.0042 (8)0.0052 (7)
C450.0339 (10)0.0275 (9)0.0201 (8)0.0113 (8)0.0025 (7)0.0037 (7)
C460.0273 (8)0.0238 (8)0.0191 (7)0.0130 (7)0.0009 (6)0.0009 (6)
C50.0218 (7)0.0226 (7)0.0168 (7)0.0117 (6)0.0008 (6)0.0010 (6)
Geometric parameters (Å, º) top
N1—C21.351 (2)C42—C431.391 (3)
N1—C51.375 (2)C42—H420.96 (2)
N1—H10.85 (2)C43—C441.389 (3)
C2—N31.326 (3)C43—H430.98 (2)
C2—H20.97 (2)C44—C451.388 (3)
N3—C41.389 (2)C44—H440.98 (3)
C4—C411.473 (3)C45—C461.392 (3)
C4—C51.374 (3)C45—H450.99 (2)
C41—C421.400 (2)C46—H460.98 (2)
C41—C461.398 (3)C5—H50.96 (2)
C2—N1—C5107.32 (13)C42—C43—C44120.2 (2)
C2—N1—H1125.7 (18)C42—C43—H43119.4 (13)
C5—N1—H1126.5 (17)C44—C43—H43120.4 (13)
N1—C2—N3111.81 (16)C43—C44—C45119.9 (2)
N1—C2—H2123.7 (14)C43—C44—H44119.2 (19)
N3—C2—H2124.4 (14)C45—C44—H44120.9 (19)
C2—N3—C4105.32 (17)C44—C45—C46120.3 (2)
N3—C4—C41122.67 (19)C44—C45—H45121.5 (17)
N3—C4—C5109.39 (17)C46—C45—H45118.1 (17)
C41—C4—C5127.85 (17)C41—C46—C45120.2 (2)
C4—C41—C42119.94 (19)C41—C46—H46120.4 (12)
C4—C41—C46120.9 (2)C45—C46—H46119.4 (12)
C42—C41—C46119.11 (18)N1—C5—C4106.15 (16)
C41—C42—C43120.3 (2)N1—C5—H5124.7 (15)
C41—C42—H42119.1 (18)C4—C5—H5129.1 (15)
C43—C42—H42120.6 (18)
(II) top
Crystal data top
C10H10N2F(000) = 336
Mr = 158.22Dx = 1.254 Mg m3
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
Hall symbol: -p 2ynCell parameters from 3206 reflections
a = 8.222 (2) Åθ = 2.9–29.0°
b = 6.026 (1) ŵ = 0.08 mm1
c = 16.948 (4) ÅT = 150 K
β = 93.283 (3)°Blade, colourless
V = 838.3 (3) Å30.6 × 0.2 × 0.1 mm
Z = 4
Data collection top
Bruker SMART CCD
diffractometer
2124 independent reflections
Radiation source: sealed tube1533 reflections with I > 2 σ(I)
Graphite monochromatorRint = 0.055
ω scansθmax = 29.0°, θmin = 2.4°
Absorption correction: multi-scan
SADABS; Sheldrick, 1996
h = 1110
Tmin = 0.94, Tmax = 0.96k = 88
9721 measured reflectionsl = 2222
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.043Hydrogen site location: difference Fourier map
wR(F2) = 0.085All H-atom parameters refined
S = 1.01 w = 1/(σ2(F) + 0.092F2)
2124 reflections(Δ/σ)max = 0.013
149 parametersΔρmax = 0.27 e Å3
0 restraintsΔρmin = 0.23 e Å3
0 constraints
Crystal data top
C10H10N2V = 838.3 (3) Å3
Mr = 158.22Z = 4
Monoclinic, P21/nMo Kα radiation
a = 8.222 (2) ŵ = 0.08 mm1
b = 6.026 (1) ÅT = 150 K
c = 16.948 (4) Å0.6 × 0.2 × 0.1 mm
β = 93.283 (3)°
Data collection top
Bruker SMART CCD
diffractometer
2124 independent reflections
Absorption correction: multi-scan
SADABS; Sheldrick, 1996
1533 reflections with I > 2 σ(I)
Tmin = 0.94, Tmax = 0.96Rint = 0.055
9721 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0430 restraints
wR(F2) = 0.085All H-atom parameters refined
S = 1.01Δρmax = 0.27 e Å3
2124 reflectionsΔρmin = 0.23 e Å3
149 parameters
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
N10.10027 (14)0.1183 (2)0.15259 (7)0.0267 (6)
C20.16118 (18)0.0532 (3)0.19304 (9)0.0292 (7)
N30.23241 (15)0.2020 (2)0.14589 (8)0.0337 (7)
C40.2157 (2)0.1209 (3)0.07134 (10)0.0369 (8)
C50.1352 (2)0.0759 (3)0.07410 (9)0.0356 (8)
C10.0145 (2)0.3122 (3)0.18706 (10)0.0337 (8)
C110.15258 (18)0.3419 (2)0.15550 (8)0.0273 (7)
C120.26760 (19)0.1722 (3)0.16198 (9)0.0307 (7)
C130.42269 (19)0.2032 (3)0.13514 (9)0.0328 (8)
C140.46448 (19)0.4054 (3)0.10267 (9)0.0327 (8)
C150.3508 (2)0.5746 (3)0.09600 (10)0.0341 (8)
C160.1949 (2)0.5431 (3)0.12225 (9)0.0319 (8)
H20.1520 (19)0.057 (3)0.2512 (10)0.027 (4)*
H40.257 (2)0.194 (3)0.0249 (11)0.041 (5)*
H50.104 (2)0.170 (4)0.0324 (12)0.052 (6)*
H1a0.007 (2)0.289 (3)0.2471 (11)0.038 (5)*
H1b0.080 (2)0.446 (4)0.1723 (12)0.053 (6)*
H120.241 (2)0.032 (3)0.1873 (10)0.041 (5)*
H130.502 (2)0.084 (4)0.1401 (11)0.052 (6)*
H140.572 (2)0.430 (3)0.0827 (10)0.040 (5)*
H150.376 (2)0.719 (4)0.0697 (12)0.057 (6)*
H160.114 (2)0.661 (3)0.1150 (11)0.046 (5)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0251 (6)0.0266 (6)0.0290 (6)0.0000 (5)0.0064 (5)0.0013 (5)
C20.0269 (7)0.0313 (8)0.0297 (7)0.0009 (6)0.0038 (6)0.0049 (6)
N30.0287 (6)0.0335 (7)0.0390 (7)0.0036 (5)0.0026 (5)0.0001 (6)
C40.0296 (8)0.0491 (10)0.0320 (8)0.0040 (7)0.0012 (6)0.0071 (7)
C50.0346 (8)0.0439 (10)0.0288 (8)0.0007 (7)0.0063 (6)0.0056 (7)
C10.0350 (8)0.0264 (8)0.0409 (9)0.0026 (6)0.0142 (7)0.0068 (7)
C110.0300 (7)0.0248 (7)0.0274 (7)0.0032 (6)0.0046 (6)0.0030 (6)
C120.0334 (7)0.0268 (7)0.0320 (8)0.0019 (6)0.0023 (6)0.0014 (6)
C130.0293 (7)0.0338 (8)0.0348 (8)0.0023 (6)0.0024 (6)0.0001 (6)
C140.0261 (7)0.0399 (9)0.0320 (8)0.0064 (6)0.0014 (6)0.0032 (7)
C150.0387 (8)0.0279 (8)0.0360 (8)0.0067 (7)0.0058 (7)0.0019 (7)
C160.0351 (8)0.0249 (7)0.0359 (8)0.0000 (6)0.0055 (6)0.0002 (6)
Geometric parameters (Å, º) top
N1—C21.352 (2)C11—C121.393 (2)
N1—C51.369 (2)C11—C161.389 (2)
N1—C11.469 (2)C12—C131.391 (2)
C2—N31.316 (2)C12—H120.98 (2)
C2—H20.984 (16)C13—C141.388 (2)
N3—C41.369 (2)C13—H130.97 (2)
C4—C51.358 (3)C14—C151.384 (2)
C4—H40.947 (18)C14—H140.974 (19)
C5—H50.95 (2)C15—C161.393 (2)
C1—C111.513 (2)C15—H151.01 (2)
C1—H1a1.025 (18)C16—H160.98 (2)
C1—H1b1.00 (2)
C2—N1—C5106.67 (13)C1—C11—C12120.75 (14)
C2—N1—C1126.14 (13)C1—C11—C16120.03 (14)
C5—N1—C1127.19 (14)C12—C11—C16119.18 (14)
N1—C2—N3112.19 (13)C11—C12—C13120.45 (15)
N1—C2—H2121.0 (10)C11—C12—H12120.2 (11)
N3—C2—H2126.8 (10)C13—C12—H12119.3 (11)
C2—N3—C4104.64 (14)C12—C13—C14120.00 (15)
N3—C4—C5110.77 (15)C12—C13—H13119.6 (12)
N3—C4—H4123.5 (12)C14—C13—H13120.4 (12)
C5—C4—H4125.7 (12)C13—C14—C15119.85 (15)
N1—C5—C4105.74 (14)C13—C14—H14121.3 (11)
N1—C5—H5124.1 (12)C15—C14—H14118.8 (11)
C4—C5—H5130.2 (12)C14—C15—C16120.18 (15)
N1—C1—C11112.25 (13)C14—C15—H15121.0 (12)
N1—C1—H1a106.5 (10)C16—C15—H15118.7 (12)
N1—C1—H1b107.7 (12)C11—C16—C15120.34 (14)
C11—C1—H1a111.2 (10)C11—C16—H16119.9 (12)
C11—C1—H1b107.8 (12)C15—C16—H16119.7 (12)
H1a—C1—H1b111.3 (15)
(III) top
Crystal data top
C12H14N2F(000) = 400
Mr = 186.28Dx = 1.200 Mg m3
Orthorhombic, Pna21Mo Kα radiation, λ = 0.71073 Å
Hall symbol: p 2c -2nCell parameters from 2807 reflections
a = 10.346 (1) Åθ = 2.9–28.8°
b = 9.222 (2) ŵ = 0.07 mm1
c = 10.803 (2) ÅT = 150 K
V = 1030.7 (3) Å3Fragment, colourless
Z = 40.35 × 0.22 × 0.16 mm
Data collection top
Bruker SMART CCD
diffractometer
1281 reflections with I > 2 σ(I)
Radiation source: sealed tubeRint = 0.072
Graphite monochromatorθmax = 29.5°, θmin = 2.9°
ω scansh = 1414
21713 measured reflectionsk = 1212
1503 independent reflectionsl = 1414
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.055Hydrogen site location: difference Fourier map
wR(F2) = 0.067H-atom parameters not refined
S = 1.07 w = 1/(σ2(F) + 0.18F2)
1503 reflections(Δ/σ)max = 0.0004
126 parametersΔρmax = 0.35 e Å3
0 restraintsΔρmin = 0.30 e Å3
0 constraints
Crystal data top
C12H14N2V = 1030.7 (3) Å3
Mr = 186.28Z = 4
Orthorhombic, Pna21Mo Kα radiation
a = 10.346 (1) ŵ = 0.07 mm1
b = 9.222 (2) ÅT = 150 K
c = 10.803 (2) Å0.35 × 0.22 × 0.16 mm
Data collection top
Bruker SMART CCD
diffractometer
1281 reflections with I > 2 σ(I)
21713 measured reflectionsRint = 0.072
1503 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0550 restraints
wR(F2) = 0.067H-atom parameters not refined
S = 1.07Δρmax = 0.35 e Å3
1503 reflectionsΔρmin = 0.30 e Å3
126 parameters
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
N10.3675 (3)0.5624 (3)0.5000 (4)0.0265 (13)
C20.3457 (3)0.6013 (4)0.6204 (4)0.0291 (15)
N30.4481 (3)0.5826 (3)0.6901 (4)0.0329 (15)
C40.5418 (3)0.5285 (4)0.6113 (4)0.0341 (18)
C50.4929 (3)0.5150 (4)0.4937 (4)0.0323 (16)
C110.2750 (3)0.5710 (4)0.4010 (4)0.0243 (14)
C120.2439 (3)0.7071 (4)0.3540 (4)0.0264 (15)
C1210.3078 (3)0.8431 (4)0.4011 (4)0.0326 (17)
C130.1515 (3)0.7133 (4)0.2591 (4)0.0290 (15)
C140.0929 (3)0.5898 (4)0.2140 (4)0.0289 (16)
C1410.0072 (3)0.6003 (4)0.1138 (4)0.0366 (18)
C150.1277 (3)0.4557 (4)0.2624 (4)0.0273 (15)
C160.2206 (3)0.4436 (4)0.3567 (4)0.0249 (15)
C1610.2589 (3)0.2975 (4)0.4036 (4)0.0318 (17)
H20.265960.639820.650280.03200*
H40.628380.502620.634660.03900*
H50.536790.479430.421740.03500*
H130.129350.806750.224530.03200*
H150.087570.369180.231500.03000*
H121a0.398290.834450.398110.04700*
H121b0.281840.859030.486110.04700*
H121c0.281220.923880.353760.04700*
H141a0.089660.609010.152900.05200*
H141b0.005530.512530.067190.05200*
H141c0.008180.682750.063480.05200*
H161a0.282120.307150.489450.04400*
H161b0.330790.264930.358500.04400*
H161c0.187690.232270.397590.04400*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0279 (13)0.0355 (14)0.0161 (11)0.0005 (12)0.0002 (11)0.0025 (12)
C20.0336 (16)0.0344 (16)0.0193 (13)0.0008 (14)0.0018 (14)0.0015 (14)
N30.0356 (15)0.0402 (15)0.0229 (14)0.0010 (13)0.0048 (13)0.0002 (13)
C40.0304 (17)0.047 (2)0.0245 (16)0.0017 (15)0.0061 (14)0.0016 (17)
C50.0275 (14)0.047 (2)0.0222 (14)0.0041 (14)0.0006 (13)0.0009 (16)
C110.0239 (14)0.0322 (15)0.0169 (12)0.0002 (13)0.0004 (13)0.0018 (13)
C120.0267 (16)0.0324 (17)0.0199 (13)0.0021 (13)0.0050 (13)0.0010 (13)
C1210.0360 (18)0.0322 (17)0.0294 (16)0.0023 (14)0.0014 (16)0.0009 (16)
C130.0288 (15)0.0348 (17)0.0234 (14)0.0023 (14)0.0019 (13)0.0044 (13)
C140.0230 (14)0.0427 (19)0.0210 (15)0.0029 (14)0.0000 (12)0.0003 (14)
C1410.0310 (17)0.051 (2)0.0277 (17)0.0002 (16)0.0084 (16)0.0018 (17)
C150.0244 (15)0.0375 (17)0.0200 (13)0.0019 (13)0.0008 (13)0.0030 (13)
C160.0237 (14)0.0332 (17)0.0179 (13)0.0018 (12)0.0035 (12)0.0003 (13)
C1610.0370 (18)0.0358 (17)0.0226 (14)0.0016 (15)0.0005 (16)0.0010 (15)
Geometric parameters (Å, º) top
N1—C21.368 (4)C121—H121c0.945
N1—C51.371 (5)C13—C141.379 (5)
N1—C111.437 (4)C13—H130.967
C2—N31.311 (5)C14—C1411.502 (6)
C2—H20.954C14—C151.390 (5)
N3—C41.383 (5)C141—H141a0.955
C4—C51.373 (6)C141—H141b0.953
C4—H40.961C141—H141c0.948
C5—H50.959C15—C161.405 (5)
C11—C121.391 (5)C15—H150.959
C11—C161.388 (5)C16—C1611.493 (5)
C12—C1211.506 (5)C161—H161a0.963
C12—C131.403 (5)C161—H161b0.939
C121—H121a0.940C161—H161c0.953
C121—H121b0.968
C2—N1—C5106.7 (3)C12—C13—C14121.6 (3)
C2—N1—C11125.7 (3)C12—C13—H13118.7
C5—N1—C11127.7 (2)C14—C13—H13119.7
N1—C2—N3112.2 (3)C13—C14—C141120.3 (3)
N1—C2—H2124.2C13—C14—C15119.2 (3)
N3—C2—H2123.6C141—C14—C15120.5 (3)
C2—N3—C4105.1 (4)C14—C141—H141a107.6
N3—C4—C5110.1 (3)C14—C141—H141b108.3
N3—C4—H4125.6C14—C141—H141c110.4
C5—C4—H4124.3H141a—C141—H141b108.8
N1—C5—C4105.9 (3)H141a—C141—H141c109.6
N1—C5—H5126.7H141b—C141—H141c112.0
C4—C5—H5127.4C14—C15—C16121.3 (3)
N1—C11—C12118.4 (3)C14—C15—H15119.8
N1—C11—C16118.6 (3)C16—C15—H15118.8
C12—C11—C16123.0 (4)C11—C16—C15117.4 (3)
C11—C12—C121121.7 (3)C11—C16—C161122.7 (3)
C11—C12—C13117.4 (3)C15—C16—C161119.9 (3)
C121—C12—C13120.8 (3)C16—C161—H161a108.0
C12—C121—H121a110.8C16—C161—H161b108.9
C12—C121—H121b109.0C16—C161—H161c110.0
C12—C121—H121c110.2H161a—C161—H161b109.4
H121a—C121—H121b108.8H161a—C161—H161c108.5
H121a—C121—H121c109.8H161b—C161—H161c112.0
H121b—C121—H121c108.2

Experimental details

(I)(II)(III)
Crystal data
Chemical formulaC9H8N2C10H10N2C12H14N2
Mr144.19158.22186.28
Crystal system, space groupTrigonal, R3cMonoclinic, P21/nOrthorhombic, Pna21
Temperature (K)150150150
a, b, c (Å)20.449 (2), 20.449 (2), 9.750 (1)8.222 (2), 6.026 (1), 16.948 (4)10.346 (1), 9.222 (2), 10.803 (2)
α, β, γ (°)90, 90, 12090, 93.283 (3), 9090, 90, 90
V3)3530.9 (6)838.3 (3)1030.7 (3)
Z1844
Radiation typeMo KαMo KαMo Kα
µ (mm1)0.080.080.07
Crystal size (mm)0.4 × 0.35 × 0.140.6 × 0.2 × 0.10.35 × 0.22 × 0.16
Data collection
DiffractometerBruker SMART CCD
diffractometer
Bruker SMART CCD
diffractometer
Bruker SMART CCD
diffractometer
Absorption correctionMulti-scan
SADABS; Sheldrick, 1996
Multi-scan
SADABS; Sheldrick, 1996
Tmin, Tmax0.920, 0.9510.94, 0.96
No. of measured, independent and
observed reflections
13318, 1043, 1022 [I > 2σ(I)]9721, 2124, 1533 [I > 2 σ(I)]21713, 1503, 1281 [I > 2 σ(I)]
Rint0.0260.0550.072
(sin θ/λ)max1)0.6820.6820.692
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.028, 0.056, 1.08 0.043, 0.085, 1.01 0.055, 0.067, 1.07
No. of reflections104321241503
No. of parameters131149126
H-atom treatmentAll H-atom parameters refinedAll H-atom parameters refinedH-atom parameters not refined
Δρmax, Δρmin (e Å3)0.16, 0.160.27, 0.230.35, 0.30

Computer programs: SMART (Siemens, 1995), SAINT (Siemens, 1995), SAINT, Xtal3.5 (Hall et al., 1995), CRYLSQ in Xtal3.5, CRYLSQin Xtal3.5, BONDLA and CIFIO in Xtal3.5.

Selected geometric parameters (Å, º) for (I) top
N1—C21.351 (2)N3—C41.389 (2)
N1—C51.375 (2)C4—C411.473 (3)
C2—N31.326 (3)C4—C51.374 (3)
C2—N1—C5107.32 (13)N3—C4—C5109.39 (17)
N1—C2—N3111.81 (16)C41—C4—C5127.85 (17)
C2—N3—C4105.32 (17)N1—C5—C4106.15 (16)
N3—C4—C41122.67 (19)
Selected geometric parameters (Å, º) for (II) top
N1—C21.352 (2)N3—C41.369 (2)
N1—C51.369 (2)C4—C51.358 (3)
N1—C11.469 (2)C1—C111.513 (2)
C2—N31.316 (2)
C2—N1—C5106.67 (13)C2—N3—C4104.64 (14)
C2—N1—C1126.14 (13)N3—C4—C5110.77 (15)
C5—N1—C1127.19 (14)N1—C5—C4105.74 (14)
N1—C2—N3112.19 (13)N1—C1—C11112.25 (13)
Selected geometric parameters (Å, º) for (III) top
N1—C21.368 (4)C2—N31.311 (5)
N1—C51.371 (5)N3—C41.383 (5)
N1—C111.437 (4)C4—C51.373 (6)
C2—N1—C5106.7 (3)C2—N3—C4105.1 (4)
C2—N1—C11125.7 (3)N3—C4—C5110.1 (3)
C5—N1—C11127.7 (2)N1—C5—C4105.9 (3)
N1—C2—N3112.2 (3)
Comparative geometries (Å,°) top
CpdRefabcdeαβγδε
NeutralMolecules
imHa1.340 (3)1.316 (3)1.369 (3)1.353 (3)1.351 (3)107.3 (2)111.7 (2)104.9 (2)109.9 (2)106.3 (2)
imMeb1.3341.2881.3631.3351.347106.6112.2104.9110.1106.2
imBnc1.352 (2)1.316 (2)1.369 (3)1.358 (3)1.369 (2)106.7 (1)112.3 (1)104.6 (1)110.8 (2)105.7 (1)
imMesc1.368 (4)1.311 (5)1.383 (5)1.373 (6)1.371 (5)106.7 (3)112.2 (3)105.1 (3)110.1 (3)105.8 (3)
4Ph-imHc1.351 (2)1.326 (3)1.389 (2)1.374 (3)1.375 (2)107.3 (1)111.8 (2)105.3 (1)109.4 (2)106.2 (2)
d1.343 (6)1.305 (7)1.384 (5)1.370 (8)1.368 (6)105.8 (3)113.6 (3)104.9 (3)108.9 (4)106.9 (4)
4-(2NH2-C6H4-)imHe1.343 (5)1.319 (5)1.362 (6)1.362 (6)1.356 (6)107.3 (3)111.3 (3)105.8 (3)108.8 (4)106.8 (4)
CationicSpecies
imH2+ f1.320 (2)1.313 (2)1.372 (2)1.344 (2)1.365 (2)108.5 (1)108.9 (1)108.6 (1)106.8 (1)107.2 (1)
g1.319 (4)1.324 (4)1.353 (4)1.350 (4)1.374 (4)108.5 (3)108.5 (3)109.1 (3)107.2 (3)106.7 (3)
1.315 (4)1.323 (4)1.372 (4)1.340 (4)1.372 (4)108.6 (3)108.9 (3)108.3 (3)107.1 (3)107.0 (3)
imMe2+ h1.324 (2)1.335 (3)1.380 (2)1.346 (3)1.376 (3)109.0 (2)108.3 (2)108.5 (2)107.1 (2)107.1 (2)
Notes:

a Bolte and Lemke, 1999 (173 K); b Wang and Craven,1979 in its cocrystallized 1:1 barbital adduct 295 K; c this work (ca 150 K); d Claramunt et al., 2002 (293 K); e Ishida et al., 1990 (295 K); f Hsu and Schlemper, 1980 (X-ray study, 295 K); g Blessing, 1986 (293 K) (2 molecules); h Arduengo et al., 1992 (203 K).
 

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