[1,5-Bis(1-methyl-1H-tetrazol-5-yl-κN)-3-oxopentane-κO]dichlorocopper(II)

The title compound, [CuCl₂(C₈H₁₄N₈O)], is the first structurally characterized molecular chelate complex of a binuclear N-substituted tetrazole. The Cu atom is five-coordinate, with an approximately square-pyramidal geometry. The equatorial positions of the pyramid are occupied by two Cl atoms and two N atoms from the ligand mol­ecule; the O atom of the ligand lies in the axial position. Each complex is connected to four others via weak C—H...Cl and C—H...N interactions, forming sheets parallel to the (010) plane.

S1. Comment

Binuclear N-substituted tetrazoles are of interest as potential chelating ligands (Downard et al., 1995). Some molecular complexes of binuclear substituted tetrazoles have been reported in the literature (Gaponik et al., 1990; Lavrenova et al., 1991; Downard et al., 1995; van Koningsbruggen et al., 2001). An inspection of the Cambridge Structural Database (release April 2001; Allen & Kennard, 1993) with respect to binuclear N-substituted tetrazole complexes revealed only a thallium(III) organometallic compound with 1,2-bis(tetrazol-5-yl)benzene as the ligand molecule (Bhandari et al., 2000). The crystal structure of a non-chelate complex of 1,2-bis(tetrazol-1-yl)propane with iron(II) perchlorate has been also reported (van Koningsbruggen et al., 2000). In this paper, we present the molecular and crystal structures of a copper(II) complex with 1,5-bis(1-methyl-1H-tetrazol-5-yl)-3-oxopentane, (I). \sch

In compound (I), the coordination polyhedron of the Cu atom is somewhat distorted from a perfect square pyramid, as is apparent from the observed τ value of 0.3 (values of 0 and 1 are indicative of idealized square-pyramidal and trigonal-bipyramidal geometries, respectively; Addison et al., 1984). The equatorial positions of the pyramid are occupied by atoms Cl1 and Cl2 [Cu1—Cl1 2.2557 (7) and Cu1—Cl2 2.2464 (7) Å], and by atoms N4 and N4' of the ligand molecule [Cu—N4 2.002 (2) and Cu—N4' 2.003 (2) Å]. These Cu—Cl and Cu—N distances are in the normal range of those previously observed for Cu^II complexes. Atom O1 of the ligand molecule lies in the axial position of the pyramid. The Cu1—O1 distance of 2.499 (2) Å is significantly longer than the usual bonding distance (Orpen et al., 1989), representing a weak Cu—O interaction. The ligand molecule is tridentate.

Both tetrazole rings of the ligand in (I) have very similar geometries. They are both planar, to within 0.006 (2) Å for the ring with primed atom numbering, and 0.003 (2) Å for the ring numbered without primes (Fig. 1). The bond distances and angles in the tetrazole fragments of (I) are consistent with those previously observed for tetrazole rings. The dihedral angle between the planes of the two tetrazole rings in the ligand molecule is 18.86 (7)°.

Inspecting the packing structure of (I), the following peculiarities may be discerned. There are no classical hydrogen bonds in the structure, but the intermolecular contacts C7—H7A···Cl2ⁱ and C7'-H7'B···N3ⁱⁱ may be noted [symmetry codes: (i) x - 1, y, z; (ii) x - 1/2, 1/2 - y, z - 1/2 Check!]. Taking these weak interactions into account, two types of infinite one-dimensional chains may be seen in the structure of (I). Chains of the first type are formed by C7—H7A···Cl2 interactions and run parallel to the a axis. Chains of the second type are due to C7'-H7'B···N3 contacts and are oriented along the [101] direction. The connection of each complex with four others via these interactions leads to sheets parallel to the (010) plane. No pronounced interaction could be found between the sheets.

Related literature

For related literature, see: Addison et al. (1984); Allen & Kennard (1993); Bhandari et al. (2000); Downard et al. (1995); Gaponik et al. (1990, 2000); Koningsbruggen et al. (2000, 2001); Lavrenova et al. (1991); Orpen et al. (1989).

S2. Experimental

1,5-bis(1-methyl-1H-tetrazol-5-yl)-3-oxopentane was synthesized by methylation of 1,5-bis(tert-butyl-1H-tetrazol-5-yl)-3-oxopentane, followed by de-tert-butylation of the intermediate tetrazolium salt according to the method previously described by Gaponik et al. (2000). The title complex was prepared by the reaction of copper(II) chloride dihydrate with 1,5-bis(1-methyl-1H-tetrazol-5-yl)-3-oxopentane in ethanol. Single crystals of (I) were grown by slow crystallization from the reaction mixture.

S3. Refinement

The H atoms were included in geometrically calculated positions, with C—H = 0.96–0.97 Å, and refined using a riding model, with U_iso(H) equal to 1.2U_eq of the corresponding C atom (1.5U_eq for methyl groups).

Computing details

Data collection: R3m Software (Nicolet, 1980); cell refinement: R3m Software; data reduction: R3m Software; program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97.

Figures

Fig. 1. The molecular view of (I) with displacement ellipsoids drawn at the 50% probability level. H atoms are shown as small spheres of arbitrary radii.

Dichloro[1,5-bis(1-methyl-1H-tetrazol-5-yl-N)-3-oxopentane-O]copper(II)

Crystal data

[CuCl2(C8H14N8O)]	F(000) = 756
Mr = 372.71	Dx = 1.773 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71069 Å
a = 8.566 (2) Å	Cell parameters from 25 reflections
b = 13.611 (3) Å	θ = 13.7–19.8°
c = 12.633 (3) Å	µ = 1.96 mm^−1
β = 108.54 (2)°	T = 293 K
V = 1396.5 (6) Å^3	Prism, blue
Z = 4	0.56 × 0.38 × 0.08 mm

Data collection

Nicolet R3m four-circle diffractometer	3547 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.020
Graphite monochromator	θmax = 30.1°, θmin = 2.3°
ω/2θ scans	h = 0→12
Absorption correction: ψ-scan (North et al., 1968)	k = 0→19
Tmin = 0.407, Tmax = 0.859	l = −17→16
4477 measured reflections	3 standard reflections every 100 reflections
4095 independent reflections	intensity decay: none

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.033	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.092	H-atom parameters constrained
S = 1.06	w = 1/[σ^2(Fo^2) + (0.0509P)^2 + 0.6526P] where P = (Fo^2 + 2Fc^2)/3
4095 reflections	(Δ/σ)max = 0.002
183 parameters	Δρmax = 0.59 e Å^−3
0 restraints	Δρmin = −0.56 e Å^−3

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq
Cu1	0.52652 (3)	0.170067 (17)	0.695871 (17)	0.02555 (8)
Cl1	0.42345 (7)	0.32391 (4)	0.67767 (5)	0.03903 (12)
Cl2	0.74107 (7)	0.06868 (5)	0.76786 (4)	0.04466 (15)
N1	0.2982 (2)	0.08927 (13)	0.92453 (13)	0.0293 (3)
N2	0.4476 (2)	0.11982 (15)	0.99103 (14)	0.0355 (4)
N3	0.5276 (2)	0.14823 (15)	0.92653 (14)	0.0360 (4)
N4	0.4335 (2)	0.13648 (13)	0.81802 (13)	0.0287 (3)
C5	0.2906 (2)	0.10005 (14)	0.81805 (15)	0.0265 (3)
C6	0.1741 (3)	0.05300 (19)	0.97218 (19)	0.0418 (5)
H6A	0.0670	0.0746	0.9269	0.063*
H6B	0.1970	0.0781	1.0466	0.063*
H6C	0.1769	−0.0175	0.9742	0.063*
C7	0.1459 (2)	0.07253 (17)	0.72136 (16)	0.0349 (4)
H7A	0.0467	0.0930	0.7367	0.042*
H7B	0.1425	0.0015	0.7145	0.042*
C8	0.1441 (2)	0.11614 (17)	0.61117 (16)	0.0336 (4)
H8A	0.0412	0.1004	0.5539	0.040*
H8B	0.1538	0.1871	0.6174	0.040*
O1	0.27936 (17)	0.07643 (12)	0.58179 (12)	0.0343 (3)
N1'	0.5721 (2)	0.17464 (13)	0.38290 (14)	0.0322 (4)
N2'	0.7324 (2)	0.18360 (16)	0.44493 (15)	0.0399 (4)
N3'	0.7372 (2)	0.18769 (16)	0.54800 (15)	0.0378 (4)
N4'	0.5815 (2)	0.18106 (12)	0.55360 (13)	0.0291 (3)
C5'	0.4799 (2)	0.17396 (14)	0.45016 (15)	0.0278 (4)
C6'	0.5254 (3)	0.1625 (2)	0.26128 (18)	0.0473 (6)
H6'A	0.4762	0.0990	0.2408	0.071*
H6'B	0.6216	0.1679	0.2383	0.071*
H6'C	0.4478	0.2126	0.2253	0.071*
C7'	0.2989 (3)	0.16411 (18)	0.41607 (17)	0.0371 (5)
H7'A	0.2545	0.1623	0.3352	0.044*
H7'B	0.2526	0.2207	0.4420	0.044*
C8'	0.2503 (3)	0.07138 (19)	0.46388 (18)	0.0423 (5)
H8'A	0.1343	0.0588	0.4268	0.051*
H8'B	0.3118	0.0165	0.4482	0.051*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cu1	0.02286 (12)	0.03424 (13)	0.01933 (11)	0.00059 (8)	0.00639 (8)	0.00151 (8)
Cl1	0.0439 (3)	0.0315 (2)	0.0397 (3)	0.00562 (19)	0.0104 (2)	−0.00060 (18)
Cl2	0.0378 (3)	0.0670 (4)	0.0321 (2)	0.0230 (3)	0.0152 (2)	0.0184 (2)
N1	0.0303 (8)	0.0372 (8)	0.0213 (7)	−0.0016 (7)	0.0096 (6)	0.0018 (6)
N2	0.0318 (8)	0.0499 (10)	0.0231 (7)	−0.0027 (7)	0.0067 (6)	−0.0003 (7)
N3	0.0300 (8)	0.0546 (11)	0.0214 (7)	−0.0050 (8)	0.0053 (6)	−0.0031 (7)
N4	0.0237 (7)	0.0409 (9)	0.0205 (7)	−0.0028 (6)	0.0056 (6)	0.0006 (6)
C5	0.0267 (8)	0.0314 (8)	0.0223 (7)	−0.0006 (7)	0.0092 (6)	0.0004 (6)
C6	0.0451 (12)	0.0535 (13)	0.0324 (10)	−0.0104 (10)	0.0201 (9)	0.0033 (9)
C7	0.0256 (9)	0.0526 (12)	0.0264 (9)	−0.0103 (8)	0.0082 (7)	0.0003 (8)
C8	0.0245 (8)	0.0498 (12)	0.0241 (8)	−0.0011 (8)	0.0044 (7)	0.0002 (8)
O1	0.0295 (7)	0.0497 (9)	0.0248 (6)	−0.0030 (6)	0.0100 (5)	−0.0025 (6)
N1'	0.0317 (8)	0.0425 (9)	0.0225 (7)	−0.0032 (7)	0.0089 (6)	0.0046 (6)
N2'	0.0318 (9)	0.0597 (12)	0.0294 (8)	−0.0090 (8)	0.0117 (7)	0.0031 (8)
N3'	0.0289 (8)	0.0565 (11)	0.0277 (8)	−0.0086 (8)	0.0084 (7)	0.0024 (7)
N4'	0.0267 (8)	0.0381 (9)	0.0227 (7)	0.0001 (6)	0.0079 (6)	0.0034 (6)
C5'	0.0281 (9)	0.0328 (9)	0.0226 (8)	0.0022 (7)	0.0079 (7)	0.0048 (6)
C6'	0.0508 (14)	0.0704 (17)	0.0223 (9)	−0.0114 (12)	0.0139 (9)	0.0002 (9)
C7'	0.0265 (9)	0.0576 (13)	0.0239 (9)	0.0046 (9)	0.0035 (7)	0.0049 (8)
C8'	0.0419 (11)	0.0576 (14)	0.0282 (9)	−0.0163 (10)	0.0123 (8)	−0.0142 (9)

Geometric parameters (Å, º)

Cu1—N4	2.002 (2)	C8—H8A	0.9700
Cu1—N4'	2.003 (2)	C8—H8B	0.9700
Cu1—Cl2	2.2464 (7)	O1—C8'	1.432 (2)
Cu1—Cl1	2.2557 (7)	N1'—C5'	1.332 (2)
Cu1—O1	2.499 (2)	N1'—N2'	1.353 (3)
N1—C5	1.334 (2)	N1'—C6'	1.469 (3)
N1—N2	1.354 (2)	N2'—N3'	1.291 (2)
N1—C6	1.464 (3)	N3'—N4'	1.361 (2)
N2—N3	1.280 (2)	N4'—C5'	1.323 (2)
N3—N4	1.361 (2)	C5'—C7'	1.477 (3)
N4—C5	1.321 (2)	C6'—H6'A	0.9600
C5—C7	1.485 (3)	C6'—H6'B	0.9600
C6—H6A	0.9600	C6'—H6'C	0.9600
C6—H6B	0.9600	C7'—C8'	1.514 (3)
C6—H6C	0.9600	C7'—H7'A	0.9700
C7—C8	1.509 (3)	C7'—H7'B	0.9700
C7—H7A	0.9700	C8'—H8'A	0.9700
C7—H7B	0.9700	C8'—H8'B	0.9700
C8—O1	1.430 (2)
N4—Cu1—N4'	166.77 (7)	O1—C8—H8B	110.0
N4—Cu1—Cl2	91.29 (5)	C7—C8—H8B	110.0
N4'—Cu1—Cl2	90.79 (5)	H8A—C8—H8B	108.3
N4—Cu1—Cl1	92.97 (5)	C8—O1—C8'	113.64 (16)
N4'—Cu1—Cl1	92.02 (5)	C8—O1—Cu1	105.38 (11)
Cl2—Cu1—Cl1	148.75 (3)	C8'—O1—Cu1	117.37 (12)
N4—Cu1—O1	81.73 (6)	C5'—N1'—N2'	109.27 (16)
N4'—Cu1—O1	85.31 (6)	C5'—N1'—C6'	130.32 (19)
Cl2—Cu1—O1	110.75 (5)	N2'—N1'—C6'	120.33 (19)
Cl1—Cu1—O1	100.50 (4)	N3'—N2'—N1'	106.78 (17)
C5—N1—N2	108.96 (16)	N2'—N3'—N4'	109.42 (17)
C5—N1—C6	130.01 (18)	C5'—N4'—N3'	107.54 (16)
N2—N1—C6	121.02 (16)	C5'—N4'—Cu1	127.74 (14)
N3—N2—N1	106.84 (16)	N3'—N4'—Cu1	124.43 (13)
N2—N3—N4	109.89 (17)	N4'—C5'—N1'	106.98 (17)
C5—N4—N3	107.22 (15)	N4'—C5'—C7'	126.47 (18)
C5—N4—Cu1	133.00 (13)	N1'—C5'—C7'	126.52 (18)
N3—N4—Cu1	119.75 (13)	N1'—C6'—H6'A	109.5
N4—C5—N1	107.08 (16)	N1'—C6'—H6'B	109.5
N4—C5—C7	128.74 (16)	H6'A—C6'—H6'B	109.5
N1—C5—C7	124.17 (17)	N1'—C6'—H6'C	109.5
N1—C6—H6A	109.5	H6'A—C6'—H6'C	109.5
N1—C6—H6B	109.5	H6'B—C6'—H6'C	109.5
H6A—C6—H6B	109.5	C5'—C7'—C8'	110.84 (18)
N1—C6—H6C	109.5	C5'—C7'—H7'A	109.5
H6A—C6—H6C	109.5	C8'—C7'—H7'A	109.5
H6B—C6—H6C	109.5	C5'—C7'—H7'B	109.5
C5—C7—C8	114.85 (17)	C8'—C7'—H7'B	109.5
C5—C7—H7A	108.6	H7'A—C7'—H7'B	108.1
C8—C7—H7A	108.6	O1—C8'—C7'	113.34 (18)
C5—C7—H7B	108.6	O1—C8'—H8'A	108.9
C8—C7—H7B	108.6	C7'—C8'—H8'A	108.9
H7A—C7—H7B	107.5	O1—C8'—H8'B	108.9
O1—C8—C7	108.63 (17)	C7'—C8'—H8'B	108.9
O1—C8—H8A	110.0	H8'A—C8'—H8'B	107.7
C7—C8—H8A	110.0
C5—N1—N2—N3	0.1 (2)	N4—Cu1—O1—C8'	176.37 (16)
C6—N1—N2—N3	−179.1 (2)	N4'—Cu1—O1—C8'	−6.32 (16)
N1—N2—N3—N4	−0.3 (2)	Cl2—Cu1—O1—C8'	−95.39 (16)
N2—N3—N4—C5	0.4 (2)	Cl1—Cu1—O1—C8'	84.86 (15)
N2—N3—N4—Cu1	−177.93 (15)	C5'—N1'—N2'—N3'	0.4 (2)
N4'—Cu1—N4—C5	−23.5 (4)	C6'—N1'—N2'—N3'	−176.6 (2)
Cl2—Cu1—N4—C5	−122.50 (19)	N1'—N2'—N3'—N4'	0.2 (2)
Cl1—Cu1—N4—C5	88.47 (19)	N2'—N3'—N4'—C5'	−0.8 (2)
O1—Cu1—N4—C5	−11.72 (19)	N2'—N3'—N4'—Cu1	173.44 (15)
N4'—Cu1—N4—N3	154.4 (3)	N4—Cu1—N4'—C5'	34.3 (4)
Cl2—Cu1—N4—N3	55.38 (16)	Cl2—Cu1—N4'—C5'	133.38 (16)
Cl1—Cu1—N4—N3	−93.65 (15)	Cl1—Cu1—N4'—C5'	−77.75 (16)
O1—Cu1—N4—N3	166.16 (16)	O1—Cu1—N4'—C5'	22.63 (16)
N3—N4—C5—N1	−0.4 (2)	N4—Cu1—N4'—N3'	−138.7 (3)
Cu1—N4—C5—N1	177.68 (14)	Cl2—Cu1—N4'—N3'	−39.63 (16)
N3—N4—C5—C7	−179.0 (2)	Cl1—Cu1—N4'—N3'	109.24 (16)
Cu1—N4—C5—C7	−1.0 (3)	O1—Cu1—N4'—N3'	−150.39 (17)
N2—N1—C5—N4	0.2 (2)	N3'—N4'—C5'—N1'	1.0 (2)
C6—N1—C5—N4	179.3 (2)	Cu1—N4'—C5'—N1'	−172.99 (13)
N2—N1—C5—C7	178.9 (2)	N3'—N4'—C5'—C7'	179.3 (2)
C6—N1—C5—C7	−1.9 (3)	Cu1—N4'—C5'—C7'	5.3 (3)
N4—C5—C7—C8	−17.9 (3)	N2'—N1'—C5'—N4'	−0.8 (2)
N1—C5—C7—C8	163.66 (19)	C6'—N1'—C5'—N4'	175.7 (2)
C5—C7—C8—O1	65.3 (2)	N2'—N1'—C5'—C7'	−179.1 (2)
C7—C8—O1—C8'	151.14 (18)	C6'—N1'—C5'—C7'	−2.6 (4)
C7—C8—O1—Cu1	−79.00 (17)	N4'—C5'—C7'—C8'	−60.8 (3)
N4—Cu1—O1—C8	48.72 (12)	N1'—C5'—C7'—C8'	117.2 (2)
N4'—Cu1—O1—C8	−133.97 (12)	C8—O1—C8'—C7'	88.5 (2)
Cl2—Cu1—O1—C8	136.97 (11)	Cu1—O1—C8'—C7'	−35.1 (2)
Cl1—Cu1—O1—C8	−42.78 (12)	C5'—C7'—C8'—O1	71.8 (2)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C7—H7A···Cl2^i	0.97	2.79	3.697 (2)	156
C7′—H7′B···N3^ii	0.97	2.59	3.484 (3)	154

Symmetry codes: (i) x−1, y, z; (ii) x−1/2, −y+1/2, z−1/2.