Search

1-(tert-Butyl)-1H-tetrazole (L) reacts with copper(ii) tetrafluoroborate hexahydrate to give the complexes [Cu2L8(H2O)2](BF4)4 (1) or [Cu3L6(H2O)6](BF4)6 (2) depending on the reaction conditions. These complexes, as well as compound L, were characterized using single crystal X-ray analysis. Complex 1 was found to comprise a dinuclear complex cation [Cu2L8(H2O)2]4+ (the Ci symmetry point group), with six tetrazole ligands L showing monodentate N4-coordination, and two ligands L providing two tetrazole ring N3,N4 bridges between the copper(ii) cations; water molecules complete the distorted octahedral coordination of the metal ions. Complex 2 includes a linear trinuclear complex cation [Cu3L6(H2O)6]6+ (the S6 symmetry point group), in which neighbouring copper(ii) cations are linked by three ligands L via tetrazole ring N3,N4 bridges; central and terminal metal ions show octahedral CuN6 and CuN3O3 coordination cores, respectively. The temperature-dependent magnetic susceptibility measurements of complex 2 revealed that the copper(ii) ions were weakly ferromagnetically coupled showing a coupling constant J of 2.2 cm−1 {H = −2J(S1S2 + S2S3)}. The quantum-chemical investigation of the electronic structure and basicity of ligand L was carried out. [ABSTRACT FROM AUTHOR]

1-tert-Butyl-1H-1,2,4-triazole (tbtr) was found to react with copper(II) chloride or bromide to give the complexes [Cu(tbtr)2X2]n and [Cu(tbtr)4X2] (X = Cl, Br). 1-tert-Butyl-1H-tetrazole (tbtt) reacts with copper(II) bromide resulting in the formation of the complex [Cu3(tbtt)6Br6]. The obtained crystalline complexes as well as free ligand tbtr were characterized by elemental analysis, IR spectroscopy, thermal and X-ray analyses. For free ligand tbtr, ¹H NMR and 13C NMR spectra were also recorded. In all the complexes, tbtr and tbtt act as monodentate ligands coordinated by CuII cations via the heteroring N4 atoms. The triazole complexes [Cu(tbtr)2Cl2]n and [Cu(tbtr)2Br2]n are isotypic, being 1D coordination polymers, formed at the expense of single halide bridges between neighboring copper(II) cations. The isotypic complexes [Cu(tbtr)4Cl2] and [Cu(tbtr)4Br2] reveal mononuclear centrosymmetric structure, with octahedral coordination of CuII cations. The tetrazole compound [Cu3(tbtt)6Br6] is a linear trinuclear complex, in which neighboring copper(II) cations are linked by single bromide bridges. [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]

1-(Furan-2-ylmethyl)-1 H-tetrazole (fmt), prepared by heterocyclization of furfurylamine with triethyl orthoformate and sodium azide, was found to react with copper(II) perchlorate, nitrate, and bromide giving complexes [Cu(fmt)4(H2O)2](ClO4)2, [Cu(fmt)3(NO3)2(H2O)], and [Cu2(fmt)4Br4], respectively. The obtained crystalline complexes and fmt were characterized by X-ray diffraction, thermal analyses, and IR spectroscopy. In the complexes, fmt acts as a monodentate ligand coordinated via the tetrazole ring N4 atom. [Cu(fmt)4(H2O)2](ClO4)2 comprises a mononuclear complex cation with an elongated CuN4O2 octahedron. [Cu(fmt)3(NO3)2(H2O)] presents a mononuclear complex, where the copper atom is in a heptacoordinate environment forming a considerably distorted pentagonal bipyramid. [Cu2(fmt)4Br4] presents a centrosymmetric dinuclear bromido-bridged complex with a square pyramidal environment of copper atoms. [ABSTRACT FROM AUTHOR]

Abstract: Complexes CuL3Cl2, PdL2Cl2 and PtL2Cl2, where L is a novel ligand from the series of 2-substituted 5-aminotetrazoles, namely 5-amino-2-tert-butyltetrazole (1), have been synthesized by the reaction of metal(II) chlorides with 1 and characterized by IR spectroscopy, thermal and X-ray analyses. The crystallographic structural analysis of these complexes revealed that 1 acts as a monodentate ligand coordinated to the metal via endocyclic N4 atom. Platinum complex demonstrates promising cytotoxicity against human cervical carcinoma cells with IC50 value average between those of cisplatin and carboplatin. [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]

Abstract: The products of the alkylation of sodium 4-nitro-1,2,3-triazolate with ethyl bromide were investigated using 1H, 13C, and 15N NMR spectroscopy. It was found that alkylation proceeds on the triazole nitrogen atoms giving a mixture of three isomeric N-ethyl-4-nitro-1,2,3-triazoles. The molar ratio of N1, N2, and N3-alkylation products was 4:8:1. The formation of a minor N3-isomer, namely 1-ethyl-5-nitro-1,2,3-triazole was confirmed by X-ray structural analysis of single crystals of its tetranuclear copper(II) complex obtained by reaction of copper(II) chloride dihydrate with a mixture of the N2 and N3-isomers. [Copyright &y& Elsevier]