Systematic Synthesis of Di-, Tri-, and Tetranuclear Homo- and Heterometal Complexes Using a Mononuclear Copper Synthon with a Tetradentate Amino Alcohol Ligand

摘要

The reaction of Cu(NO3)(2)center dot 3H(2)O with an N2O2 tetradentate amino alcohol, N,N-dibenzyl-N',N'-bis(2-hydroxyethyl)ethylenediamine (H2L), afforded the mononuclear copper complex [Cu(H2L)(NO3)](NO3) (1), which has been used to construct a series of di-, tri-, and tetranuclear homo-and heterometallic complexes. Complex 1 dimerized in the presence of NEt3 to form the Cu-2 complex [Cu-2(HL)(2)](NO3)(2) (2) by the deprotonation of one of the two hydroxy groups in the H2L ligand. The reaction of 1 with Cu(OCOH)(2) in the presence of NEt3 afforded the Cu-3 complex [Cu-3(HL)(2)(OCOH)(2)](NO3)(2) (5). The metalloligand {Cu(HL)}(+) derived from 1 reacted with M(OAc)(2) (M = Cu, Co, Zn, Ni) in the absence of NEt3 to form the asymmetric CuM dinuclear complexes [CuM(HL)(OAc)(NO3)(2)] [M = Cu (3a), Co (3b), Zn (3c), Ni (3d)], whereas in the presence of NEt3 a unit of M(OAc) was captured by two metalloligands to give the bent CuMCu trinuclear complexes [Cu2M(HL)(2)(OAc)(2)(NO3)](NO3) [M = Cu (4a), Co (4b), Mn (4c)], which were further transformed into the linear CuMCu trinuclear complexes [Cu-3(HL)(2){(PhO)(2)PO2}(2)](NO3)(2) (7a) and [Cu2M(HL)(2){(PhO)(2)PO2}(2)(MeOH)(2)](NO3)(2) [M = Co (7b), Mn (7c)] with the aid of diphenyl phosphate bridging ligands. When (PhO) PO2(OH) was used as an auxiliary bridging ligand in the reaction of 1 with M(OAc)(2) and NEt3, the Cu2M2 tetranuclear complexes [Cu2M2(HL)(2){(PhO) PO3}(2)(NO3)(2)] [M = Co (8a), Zn (8b)] were synthesized. These results demonstrate that the mononuclear copper synthon with the N2O2 tetradentate amino alcohol ligand {Cu(H2L)}(2+) generates the quite useful metalloligand {Cu(HL)}(+) by the deprotonation of a hydroxy group, and subsequent reactions lead to the construction of a series of homo-and heterometal complexes containing Cu-2, CuM (M = Cu, Co, Zn, Ni), bent-CuMCu (M = Cu, Co, Mn), linear-CuMCu (M = Cu, Co, Mn), and Cu2M2 (M = Co, Mn) cores in a systematic and selective manner.