Syntheses, crystal structures and properties of mononuclear chrominum(III) and dinuclear vanadium(III) and copper(II) complexes with a bis-bipyridyl ligand

摘要

The reaction between [VCl_3(thf)_3] and the bis-bidentate ligand L[L = 1,2-bis(2,2′-bipyridyl-6-yl)ethane] in MeOH gave the oxo-bridged dinuclear complex [V_2OCl_2L_2]Cl_2 1, which contains near linear V-O-V unit. Reaction of CrCl_3.6H_2O with L in refluxing MeOH gave mononuclear trans-[CrCl_2L]Cl 2 with the ligand L co-ordinated equatorially. Equimolar reaction of L with [Cu_2(OAc)_4(H_2O)_2]in EtOH followed by addition of NaClO_4 yielded the dinuclear complex [Cu_2(OAc)_(2.4)(OEt)_(0.6)L]ClO_4 3, whose cation contains a [Cu_2(OAc)_2(OAc_(0.4)/OEt_(0.6)]~+ core, with two bridging OAc~- ligands and a bridging oxygen atom shared by disordered OEt~- and monodentate OAc~- ligands. The analogous reaction with addition of HBF_4 gave [Cu_2F(OAc)_2L]BF_4 4, which contans two bridging OAc~- ligands and a bridging F~- atom. Compound 1 shows strong ferromagnetic coupling between vanadium(III) ions with J > 100 cm~(-1) resulting in only the S = 2 ground state being populated, whereas 4 shows weak ferromagnetic coupling, J≈ +8 cm~(-1)(H = -2JS_iS_j convention) and a S = 1 ground state.