Michail M. Degtyarik

Neutron and synchrotron X-ray powder study of copper(II) chloride complex with deuterated 1-ethyltetrazole

Abstract The structure of the copper(II) chloride complex with deuterated 1-ethyltetrazole has been investigated in the temperature range of 2–290 K using neutron and synchrotron X-ray powder diffraction. The compound was found to exhibit structural transformation at ca. 180 K, without change of space group and main structural motif. At higher temperatures, the complex reveals positional disorder of the ethyl group, whereas no disorder is observed at lower temperatures. Temperature dependence of the lattice parameters, obtained from synchrotron X-ray data, showed main lattice changes at the transformation, explained by structural features of the complex. From the magnetic measurements, the effect of the disorder on paramagnetic behaviour of the compound was found. Detailed structural data of the compound at 2 and 290 K, obtained from neutron powder diffraction data, are reported.

Coordination polymers formed by bridging 2‐substituted tetra­zole ligands: poly[[dichloro­copper(II)]‐di‐μ2‐2‐prop­yl‐2H‐tetra­zole‐κ2N1:N4] and poly[[dichloro­copper(II)]‐di‐μ2‐2‐all­yl‐2H‐tetra­zole‐κ2N1:N4]

Two polymeric complexes, [CuCl2L2]n, where L is 2-propyltetrazole (C4H8N4) or 2-allyltetrazole (C4H6N4), are the first coordination polymers of 2-substituted tetrazoles in which only the tetrazole rings bridge neighbouring Cu atoms. In both complexes, the Cu atoms lie on inversion centres and are six-coordinated in tetragonally distorted octahedral geometries, CuCl2N4, with two N1 tetrazole ring atoms in the axial positions and two Cl atoms and two N4 tetrazole ring atoms in the equatorial sites. The Cl atoms do not participate in the polymeric layer formation.

Hexa-μ2-chloro-μ4-oxo-tetrakis[(2-ethyl­tetrazole-κN4)copper(II)]

In the title molecular complex, [Cu 4 Cl 6 O(2-EtTz) 4 ], where 2-EtTz is 2-ethyltetrazole (C 3 H 6 N 4 ), the central O atom is located on the 4 symmetry site and is tetrahedrally coordinated to four Cu atoms, with Cu-O distances of 1.8966 (4) A. A very slight distortion of Cu 4 O from a regular tetrahedron is observed [two Cu-O-Cu angles are 108.76 (3)° and four others are 109.828 (13)°]. Each Cu atom is connected to three others via the Cl atoms, forming a slightly distorted Cl octahedron around the O atom, with O...Cl distances of 2.9265 (7) A for Cl atoms lying on the twofold axis and 2.9441 (13) A for those in general positions. The Cu atom has a distorted trigonal-bipyramidal environment, with three Cl atoms in the equatorial plane, and with the N atom of the 2-ethyltetrazole ligand and the μ 4 -O atom in axial positions. The Cu atom is displaced out of the equatorial plane by ca 0.91 A towards the coordinated N atom of the 2-ethyltetrazole ligand.

catena-Poly[[tetrakis(2-allyltetrazole-κN4)-tetra-μ-chloro-tricopper(II)]-di-μ-chloro]

In the crystal structure of the title compound, [Cu(3)Cl(6)(C(4)H(6)N(4))(4)](n), there are three Cu atoms, six Cl atoms and four 2-allyltetrazole ligands in the asymmetric unit. The polyhedron of one Cu atom adopts a flattened octahedral geometry, with two 2-allyltetrazole ligands in the axial positions [Cu-N4 = 1.990 (2) and 1.991 (2) A] and four Cl atoms in the equatorial positions [Cu-Cl = 2.4331 (9)-2.5426 (9) A]. The polyhedra of the other two Cu atoms have a square-pyramidal geometry, with three basal sites occupied by Cl atoms [Cu-Cl = 2.2487 (9)-2.3163 (8) and 2.2569 (9)-2.3034 (9) A] and one basal site occupied by a 2-allyltetrazole ligand [Cu-N4 = 2.028 (2) and 2.013 (2) A]. A Cl atom lies in the apical position of either pyramid [Cu-Cl = 2.8360 (10) and 2.8046 (9) A]. The possibility of including the tetrazole N3 atoms in the coordination sphere of the two Cu atoms is discussed. Neighbouring copper polyhedra share their edges with Cl atoms to form one-dimensional polymeric chains running along the a axis.

catena-Poly­[[(2-hexyl-2H-tetrazole-κN4)copper(II)]-di-μ-chloro]

In the title polymeric complex, [CuCl2(C7H14N4)]n, the Cu coordination polyhedron adopts the form of a distorted square pyramid. Basal sites of the pyramid are occupied by three Cl atoms [Cu—Cl = 2.2519 (7), 2.2842 (7) and 2.3114 (7) A] and by the N atom of the 2-hexyl-2H-tetrazole ligand [Cu—N = 2.0068 (17) A]. A Cl atom lies in the apical position, 2.6091 (6) A from the Cu atom. Neighbouring polyhedra are linked by sharing their edges with Cl atoms to form polymeric chains running along the a axis. The CH3CH2– group at the end of the hexyl chain is positionally disordered.

The chain structure of catena-poly­[[(2-tert-butyl­tetrazole-κN4)copper(II)]-di-μ-chloro]

The title compound, [CuCl2(C5H10N4)]n, is the first structurally characterized complex of a transition metal halide with a 2-monosubstituted tetrazole. The Cu atom is five-coordinated and has a distorted square-pyramidal coordination geometry. One of the basal sites of the pyramid is occupied by an N atom of the tetrazole ligand [Cu—N = 2.0131 (19) A]. A Cl atom occupies the apical position [Cu—Cl = 2.6438 (8) A] and belongs to the basal plane of the coordination pyramid of the neighbouring Cu atom. In fact, all the Cl atoms act as bridging ligands and the Cu atom coordination polyhedron shares both Cl—Cl edges with the polyhedra of two neighbouring Cu atoms, thus giving rise to polymeric chains running along the a axis of the crystal.