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For the first time, a representative of the 2,5-disubstituted tetrazoles, namely, 2-tert-butyl-5-(2-pyridyl)-2H-tetrazole (L), has been found to participate in oxidative dissolution of copper powder in homometalic systems Cu0–L–NH4X–DMSO (X = Cl, SCN, ClO4) and heterobimetallic ones Cu0–Mn(OAc)2–L–NH4OAc–Solv (Solv = DMSO, DMF), providing the formation of molecular homometallic complexes [CuL2Cl2] (1), [CuL2(SCN)2] (2), and [CuL2(H2O)](ClO4)2 (3), heterobimetallic complex [Cu2MnL2(OAc)6] (4) from DMF solution and its mixture with complex [Cu2MnL2(OAc)6]·2DMSO (5) from DMSO solution. Free ligand L and complexes 1–4 were characterized by elemental analysis, IR spectroscopy, thermal and X-ray single crystal analyses, whereas complex 5 was characterized by X-ray analysis only. Compounds 1–3 are mononuclear complexes, with chelating coordination mode of L via the tetrazole ring N4 and pyridine ring N7 atoms. Heterobimetallic complexes 4 and 5 possess trinuclear structures, with a linear Cu–Mn–Cu arrangement of the metal atoms, linked by the acetate anions; each copper(II) atom is decorated by a chelating unit of L via the tetrazole ring N1 and pyridine ring N7 atoms in complex 4, and via the N4, N7 atoms in complex 5. Temperature-dependent magnetic susceptibility measurements of complex 4 revealed a weak antiferromagnetic coupling between the paramagnetic copper(II) and manganese(II) ions (J = −2.5 cm(−1), g(Cu) = 2.25 and g(Mn) = 2.01), with magnetic exchange through the acetato bridges.

Various 2‐, 3‐ and 1'‐substituted iodoferrocenes were reacted with acetamide in the presence of copper(I) iodide (1 equiv), N,N'‐dimethylethylenediamine (1 equiv), tripotassium phosphate (2 equiv) in dioxane at 90 °C for 14 h, and allowed a large range of original 1,2‐, 1,3‐ and 1,1'‐disubstituted ferrocenes to be obtained. The results were compared as a function of the substituent and its position on the ring. DFT calculations revealed higher activation barrier for the oxidative addition in the ferrocene series when compared with classical planar aromatics. Structure‐property relationships were applied to rationalize the reactivity of the different iodoferrocenes. [ABSTRACT FROM AUTHOR]

Various aromatic ketones were first functionalized next to the carbonyl function by deprotolithiation in the presence of a zinc salt followed by iodolysis. The outcome of the reactions was analyzed, and in particular their regioselectivity in the light of the calculated pKa values. Various halogenated ketones were next involved in copper-catalyzed twofold C-N bond formation to obtain fused systems based on 2-aminopyrimidines. Besides a potential antibacterial effect, 2-aminobenzothiopyrano[4,3,2-de]quinazoline was shown to inhibit PIM1 (IC50: 0.61 μM) and CDK2/cyclin A (IC50: 2.0 μM) kinases. [ABSTRACT FROM AUTHOR]

Calculations of equilibrium geometry, vertical detachment energies (VDE) and transition energies (Te) from the electronic ground state to excited states of Cun- clusters (n=2–10) have been carried out within DFT model with the new functional developed recently [J. Mol. Struct. (Theochem) 664–665 (2003) 291]. The results of calculations have been compared with observed photoelectron spectra (PHES). The method provides a good agreement between calculations and experiment. For anionic Cu2–10- clusters, the difference between calculated and experimental values of VDE and Te for the most stable isomers does not exceed 0.21 eV. The assignment of previously unknown Cu6-, Cu8-, Cu9- and Cu10- structures has been made by both total energy calculations and comparison of experimental and calculated PHES. The electronic sructure, geometry and energetic characteristics of low-lying isomers have been studied. [Copyright &y& Elsevier]

A new tetrazole ligand, 5‐amino‐2‐isopropenyltetrazole, was prepared by regioselective alkylation of 5‐aminotetrazole with allyl bromide in sulfuric acid followed by dehydrobromination of intermediate 5‐amino‐2‐(1‐bromopropan‐2‐yl)tetrazole. 5‐Amino‐2‐isopropenyltetrazole (L) was found to react with copper(II) chloride to generate complex [CuL2Cl2]n. The ligand and its complex were characterized by single crystal X‐ray and thermal analyses. Complex [CuL2Cl2]n presents 1D coordination polymer, formed at the expense of double chlorido bridges between neighbouring octahedral coordinated CuII cations. Tetrazole ligand acts as monodentate ligand coordinated by CuII cations via the heteroring N4 atoms only. Magnetic studies revealed that the copper(II) ions were weakly antiferromagnetically coupled. Natural bond orbital analysis was performed to explain the structural peculiarities of the ligand. Its basicity and the relative stability of the protonated forms were investigated using MO calculations. [ABSTRACT FROM AUTHOR]

The interaction of 1‐phenyl‐1,4‐dihydro‐5H‐tetrazol‐5‐one (Hpto) with ethylenediamine (en) and metallic copper in ethanol in the open air was found to yield molecular complexes [Cu(en)2(pto)2] (1) or [Cu2(en)2(EtOH)2(pto)4] (2) depending on the reagents ratio. Deprotonated tetrazol‐5‐one, i.e 1‐phenyltetrazol‐5‐olate anion (pto) acts as a monodentate ligand coordinated to the metal via the tetrazole ring N4 atom in mononuclear complex 1, and as a bridging ligand coordinated via the tetrazole ring N4 and N3 atoms in binuclear complex 2. The latter was found to be a paramagnet, with a very weak antiferromagnetic exchange interaction between copper ions. [ABSTRACT FROM AUTHOR]

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]

A novel N,N′‐alkylene‐bridged bis(5‐pyridyltetrazole) ligand, namely 2,5‐bis[5‐(2‐pyridyl)‐tetrazol‐2‐yl]‐2,5‐dimethylhexane (bpt), was prepared by regioselective N2‐alkylation of 5‐(2‐pyridyl)tetrazole with 2,5‐dimethylhexane‐2,5‐diol in perchloric acid. The ligand bpt was found to react with copper(II) chloride to give the dinuclear complex [Cu2(bpt)Cl4]. According to single‐crystal X‐ray analysis of the complex, bpt acts as a chelating ligand, coordinated by the metal through the tetrazole ring N4 and the pyridine ring nitrogen atoms. In the complex molecule, two copper atoms are linked by double chlorido bridges, and ligand bpt plays the role of the third bridge. The temperature‐dependent magnetic susceptibility measurements of the complex revealed that the copper(II) ions were weakly antiferromagnetically coupled showing a coupling constant J of –1.04 cm–1. [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-(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: 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]

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]