2-tert-Butyl-5-(2-pyridyl)-2H-tetrazole as a chelating ligand in the direct synthesis of novel Cu(ii) and heterobimetallic Cu(ii)/Mn(ii) complexes

摘要

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 Cu~0-L-NH_4X-DMSO (X = Cl, SCN, ClO_4) and heterobimetallic ones Cu~0-Mn(OAc)_2-L-NH _4OAc-Solv (Solv = DMSO, DMF), providing the formation of molecular homometallic complexes [CuL_2Cl_2] (1), [CuL _2(SCN)_2] (2), and [CuL_2(H_2O)] (ClO_4)_2 (3), heterobimetallic complex [Cu _2MnL_2(OAc)_6] (4) from DMF solution and its mixture with complex [Cu_2MnL_2(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.