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Complex [Cu(tbt)Cl2]n (tbt = 1‐tert‐butyl‐1H‐tetrazole) was prepared by reaction of tbt with copper(II) chloride in solution. According to single‐crystal X‐ray analysis, this complex presents 1D coordination polymer, formed at the expense of double chlorido bridges between neighboring pentacoordinate copper(II) cations. 1‐tert‐Butyl‐1H‐tetrazole acts as monodentate ligand coordinated by CuII cations via the heteroring N4 atoms. The temperature‐dependent magnetic susceptibility measurements of novel complex [Cu(tbt)Cl2]n as well as described previously 1D coordination polymer [Cu(tbt)2Cl2]n, and linear trinuclear complex [Cu3(tbt)6Br6], were carried out. Magnetic studies revealed that the copper(II) ions were weakly ferromagnetically coupled in polymeric copper(II) chloride complexes, whereas complex [Cu3(tbt)6Br6] showed antiferromagnetic coupling. [ABSTRACT FROM AUTHOR]

Complexes [Cu 2 L 2 Cl 4 ], [NiL 2 Cl 2 ], [PdLCl 2 ], and [PtLCl 2 ], where L is a novel ligand from the series of 2-subsituted 5-(α-aminoalkyl)tetrazoles, namely 5-( N , N -dimethylaminomethyl)-2- tert -butyltetrazole, have been synthesized and characterized by IR spectroscopy, thermal analysis and single crystal X-ray analysis. The complexes reported show different coordination geometries of the metals, viz. octahedral for Ni, square pyramidal for Cu, and square planar for Pt and Pd complexes. At the same time, the ligand L demonstrates the same coordination mode in all the complexes. It acts as a chelating ligand coordinated to the metal via two nitrogen atoms, namely the tetrazole ring N 4 and the dimethylamino N atoms. Complex [PtLCl 2 ] was found to have promising antiproliferative activity against human cervical carcinoma cells, with IC 50 value being average between those of cisplatin and carboplatin. The temperature-dependent magnetic susceptibility measurements of complex [Cu 2 L 2 Cl 4 ] revealed that the copper(II) ions were weakly antiferromagnetically coupled showing a coupling constant J of −2 cm −1 . [ABSTRACT FROM AUTHOR]

1-R-Tetrazoles (R ​= ​Et, i -Pr, t -Bu) were found to react with copper(II) tetrafluoroborate hexahydrate and copper(II) nitrate tetrahydrate giving the complexes [Cu 2 L 8 (H 2 O) 2 ]X 4 , where L ​= ​1-R-tetrazole, X ​= ​BF 4 − or NO 3 −. Single crystal X-ray analysis showed that the complexes comprised dinuclear cations [Cu 2 L 8 (H 2 O) 2 ]4+, with six tetrazole ligands showing monodentate N4-coordination, and two ones providing N3,N4 bridges between the copper(II) cations; water molecules complete the distorted octahedral coordination of metal ions. Magnetic susceptibility measurements revealed that the copper(II) ions were very weakly antiferromagnetically coupled. Сomplex [Сu 2 L 8 (H 2 O) 2 ](BF 4) 4 (L ​= ​1-isopropyltetrazole) was found to exhibit a temperature induced reversible single-crystal to single-crystal polymorphic phase transition. For this complex, adiabatic calorimetry was used to find the standard thermodynamic characteristics of this transition as well as the standard thermodynamic functions of the compound in the temperature range of 80–370 ​K. Additionally, mononuclear complex of the composition [CuL 6 ](BF 4) 2 (L ​= ​1-ethyltetrazole) was obtained during the investigation and structurally characterized. Dicopper(II) complexes with N3,N4-bridging coordination of 1-alkyltetrazoles show weak antiferromagnetic coupling. Complex with 1-isopropyltetrazole exhibits a temperature induced reversible single-crystal to single-crystal polymorphic phase transition for which standard thermodynamic functions were determined. [Display omitted] • Dicopper(II) complexes with N3,N4-bridging coordination of 1-alkyltetrazoles were synthesized and characterized by X-ray analysis. • Copper(II) ions is weakly antiferromagnetically coupled in dinuclear complexes. • Dicopper(II) complex with 1-isopropyltetrazole exhibits a temperature induced single-crystal polymorphic phase transition. • Standard thermodynamic functions of complex and its transition were determined by adiabatic calorimetry. [ABSTRACT FROM AUTHOR]

A series of isostructural dinickel complexes of the type [Ni 2 (L Me2H4 )][X] 2 (where (L Me2H4 ) 2− represents a 28-membered macrocyclic N 6 S 2 donor ligand, X = ClO 4 − ( 1a ), I − ( 1b )) and [Ni 2 (L Me2H4 )( μ -L′)][X] (X = ClO 4 − , L′ = F − ( 2a ), Cl − ( 3a ), OH − ( 5a ), N 3 − ( 6a ), X = BPh 4 – , L′ = F − ( 2b ), Cl − ( 3b ), OH − ( 5b ), N 3 − ( 6b ), X = Br − , L′ = Br − ( 4 )) have been synthesized and characterized by IR, ESI-MS, UV–vis, cyclic voltammetry, SQUID magnetometry, and X-ray crystallography. The dications in 1a and 1b feature an edge sharing bis(square-pyramidal) N 3 Ni( μ -S 2 )NiN 3 core, while the monocations of 2a - 6b comprise a face-sharing bioctahedral N 3 Ni( μ -S) 2 ( μ -L′)NiN 3 core. The variation of the coordination geometry has a strong impact on the magnetic properties of the Ni complexes. 3a , 4 , and 5a have an S = 2 ground state with a value for the magnetic exchange coupling constant J of +10.06 cm −1 , ( 3a ), J = +12.13 cm −1 ( 4 ) and J = +2.9(1) cm −1 ( 5a ), while 1a , 1b , and 2a have an S = 0 ground state with J = −13.4 cm −1 ( 1a ), −22.8 cm −1 ( 1b ) and J = −0.56 cm −1 ( 2a ) ( H = – 2 JS 1 S 2 ). Broken symmetry density functional theory calculations have been performed to study the individual contributions of the coligand and thiolato-bridges to the overall magnetic behavior. The capability to propagate exchange interactions was found to increase in the order Br − < Cl − < N 3 − < OH − ∼ F − . [ABSTRACT FROM AUTHOR]

The dinuclear NiII complex [Ni2(L²)][ClO4]2 (3) supported by the 28-membered hexaaza-dithiophenolate macrocycle (L²)2- binds the N3- ion specifically end-on yielding [Ni2(L²)(μ1,1-N3)][ClO4] (7) or [Ni2(L²)(μ1,1-N3)][BPh4] (8), while the previously reported complex [Ni2L¹(μ1,3-N3)][ClO4] (2) of the 24-membered macrocycle (L¹)2- coordinates it in the end-to-end fashion. A comparison of the X-ray structures of 2, 3, and 7 reveals the form-selective binding of complex 3 to be a consequence of its preorganized, channel-like binding pocket, which accommodates the azide anion via repulsive CH•••π interactions in the end-on mode. In contrast to [Ni2L¹(μ1,3-N3)][ClO4] (2), which features a S = 0 ground state, [Ni2(L²)(μ1,1-N3)][BPh4] (8) has a S = 2 ground state that is attained by competing antiferromagnetic and ferromagnetic exchange interactions via the thiolato and azido bridges with a value for the magnetic exchange coupling constant J of 13 cm-1 (H = −2JS1S2). These results are further substantiated by density functional theory calculations. The stability of the azido-bridged complex determined by isothermal titration calorimetry in MeCN/MeOH 1/1 v/v (log K11 = 4.88(4) at I = 0.1 M) lies in between those of the fluorido- (log K11 = 6.84(7)) and chlorido-bridged complexes (log K11 = 3.52(5)). These values were found to compare favorably well with the equilibrium constants derived at lower ionic strength (I = 0.01 M) by absorption spectrophotometry (log K11 = 5.20(1), 7.77(9), and 4.13(3) for N3-, F-, and Cl- respectively). [ABSTRACT FROM AUTHOR]

Abstract: The data on synthesis, crystal structure, magnetic susceptibility and thermal properties of coordination compound of copper(II) chloride with 2-methyltetrazole (2mtet) of Cu(2mtet)2Cl2 composition are reported. The Cu atom environment forms an elongated octahedron, with two 2-methyltetrazole ligands (N4 bound) and two Cl atoms in the equatorial positions. Symmetry related 2-methyltetrazole ligand and Cl atom are in the axial positions. One of the two 2-methyltetrazole molecules of the asymmetric unit exhibits bridging properties being linked to two Cu atoms through two N atoms (i.e., N4 and N1) of the tetrazole ring, while the other ligand molecule is coordinated in monodentate fashion via one tetrazole N4 atom. The Cu-octahedra form dinuclear building bricks by sharing edges with equatorial and axial Cl atoms. These dinuclear units are linked together via bridging 2-methyltetrazole ligands to form infinite layers parallel to the plane. Magnetic properties of Cu(2mtet)2Cl2 and the data of quantum-chemical calculations of molecular electrostatic potential and energies of hydronation of nitrogen atoms for 2mtet using B3LYP/6-31G* level of theory are in agreement with the structural data obtained. [Copyright &y& Elsevier]

Abstract: Two new coordination complexes, Cu(datz)Cl2 and Cu(datz)2Cl2, where datz is 1,5-diaminotetrazole, have been obtained by the reaction of copper(II) chloride with datz. For one of them, Cu(datz)2Cl2, the crystal structure, magnetic susceptibility and thermal properties are reported. For the other compound only spectroscopic and thermal properties are presented. In Cu(datz)2Cl2 the Cu atoms were found to be octahedrally coordinated. Equatorial positions are occupied by two chloride anions and two tetrazole ligands via their N4 donor atoms. Surprisingly, the amino groups at the N1 atom of the tetrazole ring of nearby molecules are in axial positions. Each copper atom is linked with four others through the datz molecules to form 2D polymeric networks parallel to the yz plane. Magnetic properties of Cu(datz)2Cl2 and the data of quantum-chemical calculations of molecular electrostatic potential and energies of hydronation of nitrogen atoms for datz using MP2/6-31G* and B3LYP/6-31G* levels of theory are in agreement with the structural data obtained. [Copyright &y& Elsevier]

A new representative of copper(II) halide complexes with 1,5-disubstituted tetrazoles, a single chain chlorido bridged coordination polymer, shows antiferromagnetic coupling. The same type of magnetic interactions was found in other polymeric chain complexes having double chlorido bridges and N3,N4-bridges between the copper atoms. • 5-(N,N-dimethylaminomethyl)-1-(pyridin-2-yl)tetrazole acts as a chelating ligand. • New cupric chloride complex with 1,5-disubstituted tetrazole was characterized. • Mono and dichlorido-bridged copper 1D coordination polymers showed AFM coupling. The complex [Cu(5-(N,N-dimethylaminomethyl)-1-(pyridin-2-yl)tetrazole)Cl 2 ] n (1) was prepared by the reaction of 5-(N,N-dimethylaminomethyl)-1-(pyridin-2-yl)tetrazole with copper(II) chloride in solution. According to the single crystal X-ray analysis, complex 1 presents a 1D coordination polymer, formed at the expense of single chlorido bridges between neighboring pentacoordinated copper(II) cations. The tetrazole acts as a chelating ligand, coordinated via the heteroring N4 atoms and the nitrogen atom of the amino group. The temperature-dependent magnetic susceptibility measurements of complex 1 , as well as previously described chain coordination polymers [Cu(1-methyl-5-vinyltetrazole)Cl 2 ] n (2) and [Cu 2 (1-methyl-5-methylsulfonyltetrazole) 2 (H 2 O) 2 Cl 4 ] n (3), revealed that the copper(II) ions are antiferromagnetically coupled in all the complexes. A superexchange pathway between the metal cations in complex 2 is provided at the expense of double chlorido bridges and the tetrazole ring N3,N4-bridges. In complex 3 , this pathway is provided by double chlorido bridges which link alternating Cu(1-methyl-5-methylsulfonyltetrazole) 2 and Cu(H 2 O) 2 fragments. [ABSTRACT FROM AUTHOR]

Triazol-3-yl-1 H -tetrazole ligands show bridging coordination modes giving coordination polymers under action of copper(II) chloride. The peculiarity of complexation of 1-(1,2,4-triazol-3-yl)-1 H -tetrazole is the transformation of the tetrazole cycle under interaction with CuCl 2 /HCl leading to 3-amino-1,2,4-triazolium complex. 1-(1,2,4-Triazol-3-yl)-1 H -tetrazole (trt) and 1-(1- tert -butyl-1,2,4-triazol-3-yl)-1 H -tetrazole (btrt) were synthesized by heterocyclization of corresponding amines with triethyl orthoformate and sodium azide. The interaction of trt with copper(II) chloride in ethanol in the presence of hydrochloric acid was found to result in 1D coordination polymer [CuCl 2 (trt)(H 2 O)] n · n H 2 O. N - tert -butylated ligand btrt reacts with the copper salt in ethanol giving 2D coordination polymer [CuCl 2 (btrt)] n. Tetrazole ring-opening reaction with the formation of [CuCl 2 (3-amino-1,2,4-triazolium) 2 ][CuCl 4 ]·2H 2 O was observed in the interaction of trt with copper(II) chloride in aqueous hydrochloric acid. The temperature-dependent magnetic susceptibility measurements of [CuCl 2 (btrt)] n revealed that the copper(II) ions were weakly ferromagnetically coupled showing a coupling constant J of 1.2 cm−1. [ABSTRACT FROM AUTHOR]