Nickel(II) and copper(II) complexes of the 'tripod' ligand tris(2-benzimidazylmethyl)amine

A series of nickel(II) and copper(II) complexes of the title ligand are reported which appear to exhibit predominantly pseudo-octahedral structures in the solid state. Anion bridged dimeric structures are proposed for both nickel and copper; [Ni 2 (NTB) 2 X 2 ]Y2 (X = Y= Cl, Br; X = Cl, Br, NCS; Y = BPh 4 ), [Cu 2 (NTB) 2 X 2 ]X 2 •2H 2 O (X = Cl, Br). The other octahedral derivatives appear to be monomeric; (Ni(NTB)X 2 ] (X = NO 3 , NCS), [Ni(NTB)-(H 2 O)X]Y (X = NCS, Y = BPh 4 ; X = CH 3 CN, Y = (ClO 4 ) 2 ), [Ni(NTB)(H 2 O) 2 ]X 2 •2H 2 O (X = ClO 4 , BF 4 ), [Cu(NTB)(NO 3 ) 2 ]•H 2 O. Five-coordinate derivatives were uncommon and in the case of three copper complexes trigonalbipyramidal structures are suggested in the solid state; [Cu(NTB)CI]BPh 4 , [Cu(NTB)(H 2 O)]X 2 •nH 2 O (X = BF 4 , n = 0; X = ClO 4 , n = 1). In acetone solution ail the copper complexes appear to be five-coordinate. Electron spin resonance data confirm trigonalbipyramidal solution structures and indicate [Formula: see text]with very small values of [Formula: see text] (60 − 80 × 10 −4 cm −1 ).