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A nonclassical tetrazole isostere of glycine, viz. zwitterionic 5-ammoniomethyl-1H-tetrazolide, C2H5N5, (I), crystallizes in the chiral P31 space group, similar to γ-glycine. The crystal packing of (I) is determined by a set of classical hydrogen bonds, forming a three-dimensional network that is practically the same as that in γ-glycine. The CuII complex of (I), poly[[bis(μ2-5-aminomethyl-1H-tetrazolido-κ3N1,N5:N4)copper(II)] dihydrate], {[Cu(C2H4N5)2]·2H2O}n, (II), is a layered coordination polymer formed as a result of tetrazole ring bridges. The CuII cations lie on inversion centres, are surrounded by four anions and adopt elongated octahedral coordination. Water molecules are located in the interlayer space and connect the layers into a three-dimensional network via a system of hydrogen bonds.
Supporting information
CCDC references: 774016; 774017
5-Chloromethyltetrazole (1 g, 8.4 mmol), synthesized from chloroacetonitrile,
sodium azide and aluminium chloride according to the method reported by
Vereshchagin et al. (2006), was dissolved in 25% aqueous ammonia
(5 ml). The resulting solution was kept at room temperature for 1 d and
evaporated under vacuum. The residue was recrystallized from a water–ethanol
solution (10:1), yielding colourless crystals of (I) (yield 85%, 1.1 g; m.p.
560–561 K). Analysis found: C 24.31, H 5.11, N 70.71%; calculated for
C2H5N5: C 24.24, H 5.09, N 70.67%. 1H NMR (500 MHz, DMSO-d6):
δ 4.10 (s, 2H, CH2). 13C NMR (125 MHz, DMSO-d6): δ 35.2
(CH2), 156.1 (Ctetrazole).
To obtain (II), a mixture of water (20 ml), 5-aminomethyltetrazole (99 mg, 1 mmol) and copper(II) oxide (40 mg, 0.5 mmol) was refluxed for 15 h. The
resulting solution was filtered, and after slow cooling, blue crystals of (II)
suitable for X-ray analysis were obtained (yield 50%, 78 mg). Analysis found:
C 16.39, H 4.02, N 47.60%; calculated for C4H8CuN10: C 16.24, H 4.09, N
47.36%.
For (I), the systematic absences permitted the space groups P31 and
P32 as possible ones. In the absence of significant resonant
scattering, it was impossible to distinguish between these enantiomeric space
groups. In view of this, Friedel pairs were merged and the space group P31
was used. All H atoms of (I) were placed in calculated positions (C—H = 0.97 Å and N—H = 0.89 Å) and refined using a riding model [Uiso(H) =
1.2Ueq(parent)]. In (II), H atoms of the water molecules were located
from a difference map and refined with DFIX restraints for the O—H [0.88
(s.u. value?) Å] and H···H [1.41(s.u. value?) Å] distances
[Uiso(H) = 1.5Ueq(O)]. The remaining H atoms of (II) were
placed in calculated positions (C—H = 0.97 Å and N—H = 0.90 Å) and
refined using a riding model [Uiso(H) = 1.2Ueq(parent)].
For both compounds, data collection: R3m Software (Nicolet, 1980); cell refinement: R3m Software (Nicolet, 1980). Data reduction: R3m Software (Nicolet, 1980) for (I); OMNIBUS (Gałdecka, 2002) for (II). For both compounds, program(s) used to solve structure: SIR2004 (Burla et al., 2005); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2009); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).
(I) 5-ammoniomethyl-1
H-tetrazolide
top
Crystal data top
C2H5N5 | Dx = 1.548 Mg m−3 |
Mr = 99.11 | Mo Kα radiation, λ = 0.71073 Å |
Hexagonal, P31 | Cell parameters from 25 reflections |
Hall symbol: P 31 | θ = 16.2–20.2° |
a = 7.3048 (11) Å | µ = 0.12 mm−1 |
c = 6.9003 (14) Å | T = 294 K |
V = 318.87 (9) Å3 | Prism, colourless |
Z = 3 | 0.52 × 0.34 × 0.32 mm |
F(000) = 156 | |
Data collection top
Nicolet R3m four-circle diffractometer | Rint = 0.022 |
Radiation source: fine-focus sealed tube | θmax = 30.0°, θmin = 3.2° |
Graphite monochromator | h = −8→10 |
ω/2θ scans | k = −8→10 |
1076 measured reflections | l = −9→0 |
624 independent reflections | 2 standard reflections every 100 reflections |
611 reflections with I > 2σ(I) | intensity decay: none |
Refinement top
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.029 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.078 | H-atom parameters constrained |
S = 1.11 | w = 1/[σ2(Fo2) + (0.0587P)2 + 0.0056P] where P = (Fo2 + 2Fc2)/3 |
624 reflections | (Δ/σ)max < 0.001 |
65 parameters | Δρmax = 0.18 e Å−3 |
1 restraint | Δρmin = −0.20 e Å−3 |
Crystal data top
C2H5N5 | Z = 3 |
Mr = 99.11 | Mo Kα radiation |
Hexagonal, P31 | µ = 0.12 mm−1 |
a = 7.3048 (11) Å | T = 294 K |
c = 6.9003 (14) Å | 0.52 × 0.34 × 0.32 mm |
V = 318.87 (9) Å3 | |
Data collection top
Nicolet R3m four-circle diffractometer | Rint = 0.022 |
1076 measured reflections | 2 standard reflections every 100 reflections |
624 independent reflections | intensity decay: none |
611 reflections with I > 2σ(I) | |
Refinement top
R[F2 > 2σ(F2)] = 0.029 | 1 restraint |
wR(F2) = 0.078 | H-atom parameters constrained |
S = 1.11 | Δρmax = 0.18 e Å−3 |
624 reflections | Δρmin = −0.20 e Å−3 |
65 parameters | |
Special details top
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 | 0.22468 (17) | −0.00931 (18) | 0.65217 (17) | 0.0295 (2) | |
N2 | 0.2746 (2) | −0.0337 (2) | 0.46962 (18) | 0.0340 (3) | |
N3 | 0.4554 (2) | −0.0278 (3) | 0.46749 (17) | 0.0429 (3) | |
N4 | 0.5299 (2) | −0.0011 (3) | 0.65017 (17) | 0.0397 (3) | |
C5 | 0.38522 (19) | 0.01011 (18) | 0.75824 (17) | 0.0265 (2) | |
C6 | 0.4073 (2) | 0.0440 (3) | 0.9722 (2) | 0.0368 (3) | |
H6A | 0.4737 | −0.0309 | 1.0266 | 0.044* | |
H6B | 0.4979 | 0.1934 | 0.9990 | 0.044* | |
N7 | 0.19875 (19) | −0.03152 (18) | 1.06593 (15) | 0.0286 (2) | |
H7A | 0.1435 | 0.0461 | 1.0252 | 0.034* | |
H7B | 0.2151 | −0.0197 | 1.1940 | 0.034* | |
H7C | 0.1125 | −0.1663 | 1.0348 | 0.034* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
N1 | 0.0305 (5) | 0.0415 (6) | 0.0216 (5) | 0.0217 (4) | 0.0000 (4) | 0.0006 (4) |
N2 | 0.0364 (6) | 0.0500 (7) | 0.0205 (5) | 0.0253 (5) | 0.0009 (4) | 0.0022 (4) |
N3 | 0.0426 (7) | 0.0722 (9) | 0.0245 (6) | 0.0366 (7) | 0.0029 (4) | 0.0009 (5) |
N4 | 0.0355 (6) | 0.0654 (8) | 0.0281 (6) | 0.0328 (6) | −0.0007 (4) | −0.0006 (5) |
C5 | 0.0281 (5) | 0.0312 (5) | 0.0216 (5) | 0.0157 (4) | −0.0015 (4) | −0.0011 (4) |
C6 | 0.0368 (6) | 0.0514 (8) | 0.0229 (6) | 0.0225 (6) | −0.0059 (5) | −0.0078 (5) |
N7 | 0.0405 (6) | 0.0341 (5) | 0.0179 (4) | 0.0236 (5) | −0.0014 (4) | −0.0012 (4) |
Geometric parameters (Å, º) top
N1—C5 | 1.3284 (16) | C6—N7 | 1.4841 (19) |
N1—N2 | 1.3478 (17) | C6—H6A | 0.9700 |
N2—N3 | 1.2995 (19) | C6—H6B | 0.9700 |
N3—N4 | 1.3479 (17) | N7—H7A | 0.8900 |
N4—C5 | 1.3288 (16) | N7—H7B | 0.8900 |
C5—C6 | 1.4926 (17) | N7—H7C | 0.8900 |
| | | |
C5—N1—N2 | 104.26 (11) | N7—C6—H6B | 109.4 |
N3—N2—N1 | 110.11 (11) | C5—C6—H6B | 109.4 |
N2—N3—N4 | 108.91 (11) | H6A—C6—H6B | 108.0 |
C5—N4—N3 | 104.95 (11) | C6—N7—H7A | 109.5 |
N1—C5—N4 | 111.77 (12) | C6—N7—H7B | 109.5 |
N1—C5—C6 | 125.39 (11) | H7A—N7—H7B | 109.5 |
N4—C5—C6 | 122.83 (11) | C6—N7—H7C | 109.5 |
N7—C6—C5 | 111.32 (11) | H7A—N7—H7C | 109.5 |
N7—C6—H6A | 109.4 | H7B—N7—H7C | 109.5 |
C5—C6—H6A | 109.4 | | |
| | | |
C5—N1—N2—N3 | −0.36 (16) | N3—N4—C5—N1 | 0.31 (18) |
N1—N2—N3—N4 | 0.6 (2) | N3—N4—C5—C6 | −178.77 (14) |
N2—N3—N4—C5 | −0.5 (2) | N1—C5—C6—N7 | 23.31 (19) |
N2—N1—C5—N4 | 0.02 (15) | N4—C5—C6—N7 | −157.74 (14) |
N2—N1—C5—C6 | 179.07 (13) | | |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N7—H7A···N1i | 0.89 | 2.07 | 2.9443 (15) | 169 |
N7—H7B···N2ii | 0.89 | 1.97 | 2.8417 (18) | 168 |
N7—H7B···N3ii | 0.89 | 2.60 | 3.3379 (17) | 141 |
N7—H7C···N4iii | 0.89 | 1.97 | 2.8300 (18) | 162 |
Symmetry codes: (i) −y, x−y, z+1/3; (ii) x, y, z+1; (iii) −y, x−y−1, z+1/3. |
(II) poly[[bis(µ
2-5-aminomethyl-1
H-tetrazolido-
κ3N1,
N5:
N4)copper(II)] dihydrate]
top
Crystal data top
[Cu(C2H4N5)2]·2H2O | F(000) = 302 |
Mr = 295.79 | Dx = 1.815 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 25 reflections |
a = 7.0452 (18) Å | θ = 17.4–25.2° |
b = 8.907 (2) Å | µ = 2.03 mm−1 |
c = 9.059 (2) Å | T = 294 K |
β = 107.80 (2)° | Block, blue |
V = 541.3 (2) Å3 | 0.38 × 0.34 × 0.28 mm |
Z = 2 | |
Data collection top
Nicolet R3m four-circle diffractometer | 1406 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.012 |
Graphite monochromator | θmax = 30.1°, θmin = 3.0° |
ω/2θ scans | h = −9→9 |
Absorption correction: ψ scan (North et al., 1968) | k = 0→12 |
Tmin = 0.483, Tmax = 0.563 | l = 0→12 |
1681 measured reflections | 2 standard reflections every 100 reflections |
1590 independent reflections | intensity decay: none |
Refinement top
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.025 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.076 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.11 | w = 1/[σ2(Fo2) + (0.0433P)2 + 0.208P] where P = (Fo2 + 2Fc2)/3 |
1590 reflections | (Δ/σ)max < 0.001 |
85 parameters | Δρmax = 0.36 e Å−3 |
3 restraints | Δρmin = −0.56 e Å−3 |
Crystal data top
[Cu(C2H4N5)2]·2H2O | V = 541.3 (2) Å3 |
Mr = 295.79 | Z = 2 |
Monoclinic, P21/c | Mo Kα radiation |
a = 7.0452 (18) Å | µ = 2.03 mm−1 |
b = 8.907 (2) Å | T = 294 K |
c = 9.059 (2) Å | 0.38 × 0.34 × 0.28 mm |
β = 107.80 (2)° | |
Data collection top
Nicolet R3m four-circle diffractometer | 1406 reflections with I > 2σ(I) |
Absorption correction: ψ scan (North et al., 1968) | Rint = 0.012 |
Tmin = 0.483, Tmax = 0.563 | 2 standard reflections every 100 reflections |
1681 measured reflections | intensity decay: none |
1590 independent reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.025 | 3 restraints |
wR(F2) = 0.076 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.11 | Δρmax = 0.36 e Å−3 |
1590 reflections | Δρmin = −0.56 e Å−3 |
85 parameters | |
Special details top
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 | |
Cu1 | 0.0000 | 0.0000 | 0.0000 | 0.02128 (10) | |
N1 | −0.11094 (18) | 0.10998 (14) | −0.20149 (13) | 0.0217 (2) | |
N2 | −0.2743 (2) | 0.11299 (16) | −0.32578 (15) | 0.0277 (3) | |
N3 | −0.2449 (2) | 0.20914 (17) | −0.42555 (16) | 0.0313 (3) | |
N4 | −0.0614 (2) | 0.27161 (16) | −0.36870 (15) | 0.0281 (3) | |
C5 | 0.0154 (2) | 0.20769 (17) | −0.23077 (16) | 0.0221 (3) | |
C6 | 0.2151 (2) | 0.22943 (19) | −0.11343 (18) | 0.0288 (3) | |
H6A | 0.3160 | 0.2467 | −0.1643 | 0.035* | |
H6B | 0.2128 | 0.3149 | −0.0476 | 0.035* | |
N7 | 0.25832 (19) | 0.08992 (15) | −0.02071 (14) | 0.0236 (2) | |
H7A | 0.3425 | 0.1101 | 0.0741 | 0.028* | |
H7B | 0.3176 | 0.0231 | −0.0669 | 0.028* | |
O1 | 0.5998 (2) | 0.0454 (2) | 0.27623 (17) | 0.0449 (4) | |
H1A | 0.516 (4) | −0.010 (3) | 0.302 (4) | 0.067* | |
H1B | 0.649 (4) | 0.108 (3) | 0.350 (3) | 0.067* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
Cu1 | 0.02003 (14) | 0.02418 (15) | 0.01836 (14) | −0.00115 (8) | 0.00399 (9) | 0.00694 (8) |
N1 | 0.0232 (6) | 0.0224 (5) | 0.0180 (5) | −0.0026 (4) | 0.0042 (4) | 0.0017 (4) |
N2 | 0.0280 (6) | 0.0287 (6) | 0.0223 (6) | −0.0044 (5) | 0.0015 (5) | 0.0036 (5) |
N3 | 0.0341 (7) | 0.0319 (7) | 0.0225 (6) | −0.0061 (6) | 0.0004 (5) | 0.0054 (5) |
N4 | 0.0327 (7) | 0.0283 (6) | 0.0210 (6) | −0.0056 (5) | 0.0045 (5) | 0.0061 (5) |
C5 | 0.0250 (6) | 0.0211 (6) | 0.0193 (6) | −0.0024 (5) | 0.0052 (5) | 0.0023 (5) |
C6 | 0.0269 (7) | 0.0296 (7) | 0.0265 (7) | −0.0083 (6) | 0.0033 (6) | 0.0060 (6) |
N7 | 0.0217 (5) | 0.0269 (6) | 0.0208 (5) | 0.0000 (5) | 0.0043 (4) | 0.0027 (4) |
O1 | 0.0425 (8) | 0.0638 (9) | 0.0304 (7) | −0.0195 (8) | 0.0142 (6) | −0.0106 (7) |
Geometric parameters (Å, º) top
Cu1—N1 | 2.0075 (12) | N4—C5 | 1.3284 (18) |
Cu1—N1i | 2.0075 (12) | N4—Cu1iv | 2.4605 (14) |
Cu1—N7i | 2.0488 (13) | C5—C6 | 1.494 (2) |
Cu1—N7 | 2.0488 (13) | C6—N7 | 1.479 (2) |
Cu1—N4ii | 2.4605 (14) | C6—H6A | 0.9700 |
Cu1—N4iii | 2.4606 (14) | C6—H6B | 0.9700 |
N1—C5 | 1.3283 (18) | N7—H7A | 0.9000 |
N1—N2 | 1.3419 (18) | N7—H7B | 0.9000 |
N2—N3 | 1.3066 (19) | O1—H1A | 0.852 (17) |
N3—N4 | 1.357 (2) | O1—H1B | 0.856 (16) |
| | | |
N1—Cu1—N1i | 180.0 | C5—N4—N3 | 104.36 (13) |
N1—Cu1—N7i | 99.45 (5) | C5—N4—Cu1iv | 136.71 (10) |
N1i—Cu1—N7i | 80.55 (5) | N3—N4—Cu1iv | 116.33 (10) |
N1—Cu1—N7 | 80.55 (5) | N1—C5—N4 | 111.32 (13) |
N1i—Cu1—N7 | 99.45 (5) | N1—C5—C6 | 119.05 (13) |
N7i—Cu1—N7 | 180.0 | N4—C5—C6 | 129.62 (14) |
N1—Cu1—N4ii | 92.35 (5) | N7—C6—C5 | 106.31 (12) |
N1i—Cu1—N4ii | 87.65 (5) | N7—C6—H6A | 110.5 |
N7i—Cu1—N4ii | 90.76 (5) | C5—C6—H6A | 110.5 |
N7—Cu1—N4ii | 89.24 (5) | N7—C6—H6B | 110.5 |
N1—Cu1—N4iii | 87.65 (5) | C5—C6—H6B | 110.5 |
N1i—Cu1—N4iii | 92.35 (5) | H6A—C6—H6B | 108.7 |
N7i—Cu1—N4iii | 89.24 (5) | C6—N7—Cu1 | 110.25 (9) |
N7—Cu1—N4iii | 90.76 (5) | C6—N7—H7A | 109.6 |
N4ii—Cu1—N4iii | 180.0 | Cu1—N7—H7A | 109.6 |
C5—N1—N2 | 105.93 (12) | C6—N7—H7B | 109.6 |
C5—N1—Cu1 | 113.76 (10) | Cu1—N7—H7B | 109.6 |
N2—N1—Cu1 | 140.21 (10) | H7A—N7—H7B | 108.1 |
N3—N2—N1 | 108.48 (12) | H1A—O1—H1B | 108 (2) |
N2—N3—N4 | 109.90 (13) | | |
| | | |
N7i—Cu1—N1—C5 | 166.13 (11) | Cu1—N1—C5—N4 | 176.79 (10) |
N7—Cu1—N1—C5 | −13.87 (11) | N2—N1—C5—C6 | −179.38 (14) |
N4ii—Cu1—N1—C5 | −102.71 (11) | Cu1—N1—C5—C6 | −2.31 (18) |
N4iii—Cu1—N1—C5 | 77.29 (11) | N3—N4—C5—N1 | 0.23 (18) |
N7i—Cu1—N1—N2 | −18.28 (17) | Cu1iv—N4—C5—N1 | 160.20 (12) |
N7—Cu1—N1—N2 | 161.72 (17) | N3—N4—C5—C6 | 179.21 (16) |
N4ii—Cu1—N1—N2 | 72.88 (17) | Cu1iv—N4—C5—C6 | −20.8 (3) |
N4iii—Cu1—N1—N2 | −107.12 (17) | N1—C5—C6—N7 | 24.03 (19) |
C5—N1—N2—N3 | 0.21 (17) | N4—C5—C6—N7 | −154.89 (16) |
Cu1—N1—N2—N3 | −175.59 (13) | C5—C6—N7—Cu1 | −33.33 (15) |
N1—N2—N3—N4 | −0.08 (19) | N1—Cu1—N7—C6 | 26.92 (10) |
N2—N3—N4—C5 | −0.09 (19) | N1i—Cu1—N7—C6 | −153.08 (10) |
N2—N3—N4—Cu1iv | −164.89 (11) | N4ii—Cu1—N7—C6 | 119.43 (10) |
N2—N1—C5—N4 | −0.28 (17) | N4iii—Cu1—N7—C6 | −60.57 (10) |
Symmetry codes: (i) −x, −y, −z; (ii) −x, y−1/2, −z−1/2; (iii) x, −y+1/2, z+1/2; (iv) −x, y+1/2, −z−1/2. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N7—H7A···O1 | 0.90 | 2.22 | 3.037 (2) | 150 |
N7—H7B···O1v | 0.90 | 2.23 | 3.037 (2) | 149 |
O1—H1A···N2i | 0.85 (2) | 2.01 (2) | 2.842 (2) | 167 (3) |
O1—H1B···N3vi | 0.86 (2) | 2.14 (2) | 2.969 (2) | 163 (3) |
Symmetry codes: (i) −x, −y, −z; (v) −x+1, −y, −z; (vi) x+1, y, z+1. |
Experimental details
| (I) | (II) |
Crystal data |
Chemical formula | C2H5N5 | [Cu(C2H4N5)2]·2H2O |
Mr | 99.11 | 295.79 |
Crystal system, space group | Hexagonal, P31 | Monoclinic, P21/c |
Temperature (K) | 294 | 294 |
a, b, c (Å) | 7.3048 (11), 7.3048 (11), 6.9003 (14) | 7.0452 (18), 8.907 (2), 9.059 (2) |
α, β, γ (°) | 90, 90, 120 | 90, 107.80 (2), 90 |
V (Å3) | 318.87 (9) | 541.3 (2) |
Z | 3 | 2 |
Radiation type | Mo Kα | Mo Kα |
µ (mm−1) | 0.12 | 2.03 |
Crystal size (mm) | 0.52 × 0.34 × 0.32 | 0.38 × 0.34 × 0.28 |
|
Data collection |
Diffractometer | Nicolet R3m four-circle diffractometer | Nicolet R3m four-circle diffractometer |
Absorption correction | – | ψ scan (North et al., 1968) |
Tmin, Tmax | – | 0.483, 0.563 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 1076, 624, 611 | 1681, 1590, 1406 |
Rint | 0.022 | 0.012 |
(sin θ/λ)max (Å−1) | 0.704 | 0.705 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.029, 0.078, 1.11 | 0.025, 0.076, 1.11 |
No. of reflections | 624 | 1590 |
No. of parameters | 65 | 85 |
No. of restraints | 1 | 3 |
H-atom treatment | H-atom parameters constrained | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.18, −0.20 | 0.36, −0.56 |
Selected bond lengths (Å) for (I) topN1—C5 | 1.3284 (16) | N3—N4 | 1.3479 (17) |
N1—N2 | 1.3478 (17) | N4—C5 | 1.3288 (16) |
N2—N3 | 1.2995 (19) | | |
Hydrogen-bond geometry (Å, º) for (I) top
D—H···A | D—H | H···A | D···A | D—H···A |
N7—H7A···N1i | 0.89 | 2.07 | 2.9443 (15) | 169.2 |
N7—H7B···N2ii | 0.89 | 1.97 | 2.8417 (18) | 168.0 |
N7—H7B···N3ii | 0.89 | 2.60 | 3.3379 (17) | 141.1 |
N7—H7C···N4iii | 0.89 | 1.97 | 2.8300 (18) | 162.2 |
Symmetry codes: (i) −y, x−y, z+1/3; (ii) x, y, z+1; (iii) −y, x−y−1, z+1/3. |
Selected bond lengths (Å) for (II) topCu1—N1 | 2.0075 (12) | Cu1—N4i | 2.4605 (14) |
Cu1—N7 | 2.0488 (13) | | |
Symmetry code: (i) −x, y−1/2, −z−1/2. |
Hydrogen-bond geometry (Å, º) for (II) top
D—H···A | D—H | H···A | D···A | D—H···A |
N7—H7A···O1 | 0.90 | 2.22 | 3.037 (2) | 150. |
N7—H7B···O1ii | 0.90 | 2.23 | 3.037 (2) | 149. |
O1—H1A···N2iii | 0.852 (17) | 2.005 (19) | 2.842 (2) | 167 (3) |
O1—H1B···N3iv | 0.856 (16) | 2.141 (19) | 2.969 (2) | 163 (3) |
Symmetry codes: (ii) −x+1, −y, −z; (iii) −x, −y, −z; (iv) x+1, y, z+1. |
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The tetrazole ring is extensively used in molecular design and in the synthesis of modified amino acids and peptidomimetics, because the tetrazol-5-yl group, –CN4H, is a nonclassical isostere for the carboxylic acid group, –COOH. These functional groups have similar chemical properties and may be interchangeable, resulting in compounds with similar biological properties. Moreover, the tetrazol-1,5-diyl group, –CN4–, is a cis-amide –C(═O)N– surrogate (Ostrovskii et al., 2008). In particular, 5-aminomethyltetrazole and its derivatives form an interesting class of tetrazole analogues of natural α-amino acids. Moreover, they are the precursors of dipeptides, attractive as catalysts for the direct asymmetric intermolecular aldol reaction (Zheng, Li et al., 2006). However, very little has appeared in the literature concerning their structure. Only a few examples of 5-aminomethyltetrazole derivatives have been structurally characterized. These are zwitterionic 5-(piperidiniomethyl)-1H-tetrazolide (Lyakhov et al., 2003), 1-phenyl-5-(piperidinomethyl)-1H-tetrazole (Lyakhov et al., 2004) and (S)-N-(1H-tetrazol-5-ylmethyl)pyrrolidine-2-carboxamide dihydrate (Zheng, Zhang et al., 2006). In spite of interest in the coordination chemistry of these compounds, mainly potentiometric and spectroscopic (UV-vis, circular dichroism and electron paramagnetic resonance) studies have been undertaken (Lodyga-Chruscinska et al., 2006, and references therein), and only the structure of a copper(II) chloride complex with N,N-dimethyl-1-(1-methyl-1H-tetrazol-5-yl) methanamine has been reported (Ivashkevich et al., 2002).
The present paper is concerned with 5-methylaminotetrazole, existing in the crystal in zwitterionic form as 5-(ammoniomethyl)-1H-tetrazolide, (I). The compound is a tetrazol-5-yl analogue of the simplest α-amino acid, glycine. Here we present also a CuII complex of (I), poly[[[bis(µ-5-aminomethyltetrazolato-κ3N1,N':N4)]copper(II)] dihydrate], (II). It should be noted that compound (I) was synthesized 50 years ago (McManus & Herbst, 1959). As to its metal derivatives, they are hitherto unknown.
Compound (I), whose molecules are achiral in solution, crystallizes in the enantiomeric pair of chiral space groups P31 and P32. It may be expected that the distribution of the crystalline product between the two space groups is essentially statistical.
Zwitterions (I) are produced when the H atom of the tetrazole ring is transferred to the amine group N atom (Fig. 1). As a consequence, the tetrazole ring is rather symmetrical (Table 1). The C5—N1 and C5—N4 bond lengths are practically the same, and a similar situation is observed for the N1—N2 and N3—N4 bonds. The N2═N3 bond is the shortest in the ring. The tetrazole ring is essentially planar, to within 0.0021 (10) Å, so the ring symmetry is close to C2v. The obtained ring geometry corresponds to charge delocalization in the N1—C5—N4 fragment.
All H atoms of the NH3 groups are involved in classical intermolecular hydrogen bonding (Table 2). Bifurcated hydrogen bonds [N7—H7B···N2ii and N7—H7B···N3ii; symmetry code: (ii) x, y, z + 1] connect the zwitterions into chains running along the c axis. These chains are bonded through lateral hydrogen bonds (N7—H7A···N1i and N7—H7C···N4iii; symmetry codes: (i) -y, x - y, z + 1/3; (iii) -y, x - y - 1, z + 1/3) to form a three-dimensional network (Fig. 2).
It is of interest to compare the structure of (I) with that of glycine, which crystallizes in three polymorphic forms, α (P21/n), β (P21) and γ (P31), reported previously (Boldyreva et al., 2003, and references therein). The analysis showed that the structure of (I) was very close to that of γ-glycine. Both compounds are achiral but crystallize in the same chiral space group P31 (P32). In (I), the values of the cell dimensions are somewhat higher than those in γ-glycine, in agreement with the sizes of the molecules. In both compounds, the crystal packing is practically the same, being determined by similar hydrogen bonds [N—H···N in (I) and N—H···O in γ-glycine].
The asymmetric unit of complex (II) is shown in Fig. 3. The CuII cations lie on inversion centres and are surrounded by four anions to form an elongated octahedral coordination (Table 3). The tetrazole ring N4 atoms of two tetrazolate anions lie in axial positions of the octahedron. Two other anions in the CuII environment are coordinated bidentately via atoms N1 and N7, occupying equatorial sites of the octahedron. Within 3σ, the tetrazole ring bond lengths are the same as those in (I). Moreover, the complexing has practically no influence on the C5-substituent conformation. Complex (II) is a layered coordination polymer, with layers parallel to the bc plane. Within a layer, each ligand acts as a bridge between adjacent Cu cations, separated by ca 6.35 Å (Fig. 4). Water molecules, located in the interlayer space, connect the layers into a three-dimensional network via a system of hydrogen bonds, each molecule acting as both a donor and an acceptor of H atoms (Fig. 5 and Table 4). Although the water molecules are not coordinated to the Cu atoms, the solvent molecules play an important role in the crystal packing. According to the thermal analysis data, the complex shows high thermal stability and does not reveal water loss up to decomposition, which takes place as an exothermal process at 514 K. Note that the only reported CuII complex of glycine (Casari et al., 2004, and references therein) is different from (II) in composition and crystal structure, including the CuII coordination environment, polymeric structure and hydrogen-bond system.