Mono- and dinuclear alkoxide copper complexes with PPh3 ligands

Article abstract of DOI:10.1016/0022-328X(94)80138-X

Methylcopper complex, CuMe(PPh3)2(Et2O)0.5 (1) reacts with HOCH(CF3)2 to give Cu(OCH(CF3)2)(PPh3)3 (2a).Similar reactions of 1 with HOCHPh2 give Cu(OCHPh2)(PPh3)3 (3a) or Cu(OCHPh2)(PPh3)2 (3b) depending on the reaction conditions.Reaction of 1 and phenol with addition of PPh3 gives Cu(OPh)(PPh3)3 (4a).The 1H NMR spectra and results of elemental analyses of 2a, 3a, 3b, and 4a agree well with the proposed formula.Complex 2a crystallizes in the orthorhombic space group Pn2₁a, with a = 18.804(2) Angstroem, b = 19.655(4) Angstroem, c = 13.175(3) Angstroem, Z = 4, and V = 4869 Angstroem³.The Cu center is in pseudotetrahedral coordination with the Cu-O distance of 2.087(6) Angstroem.Phenoxide copper complex, Cu(OPh)(PPh3)2 (4b), which is prepared from the already reported reaction of 1 with phenol, crystallizes in the monoclinic space group P2, with a = 13.955(3) Angstroem, b = 17.610(3) Angstroem, c = 13.961(3) Angstroem, β = 90.06(2) deg, Z = 2, and V = 3430 Angstroem³.The molecule has a dinuclear structure in which two pseudotetrahedral Cu centers are bridged by two μ²-phenoxide ligands.Complex 3a reacts with HOCH(CF3)2 to give 2a, while reactions of the fluoro alcohol with 3b give 2a or Cu(OCH(CF3)2)(PPh3)2 (2b) depending on the conditions.Reaction of HOCHPh2 with 2a does not cause the alkoxide ligand exchange.Complex 2a reacts with phenol and with phenyl acetate to give 4b in high yields, while 4b does not undergo exchange of the phenoxide ligand by HOCH(CF3)2.Reaction of 3a with 1,4-diethynylbenzene gives a copper complex formulated as (Ph3P)Cu(C<*>CC6H4C<*>C)Cu(PPh3) (5).The PEt3 coordinated complex (Et3P)Cu(C<*>CC6H4C<*>C)Cu(PEt3) (6) is prepared by reaction of PEt3 with 5.Key words: Copper; Alkoxide; Hydrogen bonding; Crystal structure