COMPLEXES OF DI- AND TERVALENT COBALT, MONO- AND DIVALENT COPPER WITH 2-(2-ARYLTELLUROETHYL) PYRIDINES: SYNTHESIS AND SPECTRA

Abstract

Abstract Complexes of 2-(2-phenyltelluroethyl)pyridine (L1) and 2-{2-(4-methoxyphenyl}telluro) ethylpyridine (L2) with Co(II and III) and Cu(I and II) having compositions [Co(L)Br2] (1, 2), [Co(L)2]BPh4 (3, 4), [Cu(L)Br]2 (5) and [Cu(L)2Br]2(BPh4)2 (6) have been synthesized and characterized by molecular weight, molar conductance, ESR, IR, 1H and 125Te{1H} NMR and electronic spectra in conjunction with magnetic susceptibility measurements and ESCA (in case of Cu (II)). The species 6 is diamagnetic and ESR silent because the odd electron of each copper is paired as two basal coordination planes are coplanar. The μeff values of 1 and 2 (3.5–3.7 BM) indicate the existence of the equilibrium which is supported by molecular weight and ΛM values. The v(Cu[sbnd]Br) stretch at 181 cm−1 in the IR spectrum of 5 indicates that it is a bromine bridged dimer. The 125Te {1H} NMR signal of L2 undergoes an upfield shift (141 ppm) on coordination with Cu(I). Deshielding of up to 1 ppm of the CH2Te signal in 1H NMR spectra...