Síntese e análise estrutural de novos polímeros de coordenação e compostos moleculares de fosfinatos metálicos

Abstract

In this work, the structures of coordination polymers and molecular compounds Cu(II), Hg(II), Pb(II) and Cd(II) with phenylphosphinate or diphenylphosphinate ligands were determined and are discussed. The reaction of phenylphosphinic or diphenylphosphinic acid with copper(II) acetate hydrate produces respectively aquaphenylphosphinate copper(II) or quadiphenylphosphinate copper(II), both insoluble polymeric compounds. The formation of adducts by dissolving these compounds in methanol in the presence of Lewis bases, such as pyridine or N, N, N , N -tetramethylethylenediamine (tmeda), breaks the polymeric chains. Slow evaporation under an inert atmosphere of solutions of the adducts formed crystals for the complexes [Cu{O2P(H)Ph}2(NC5H5)2(OH2)] (1.1), [Cu{O2PPh2}2(NC5H5)2(OH2)] (2.1) e [Cu{O2PPh2}2{(CH3)2N(CH2)2N(CH3)2}(OH2)] (2.2). There are intra and intermoleculares interactions between ligands molecules. Strong hydrogen bond interactions form a supramolecular arrangement in the two structures, those of 1.1 e 2.1. The novel diphenylphosphinate bridged coordination polymer catena- [Hg(μ2O2PPh2)] was synthesized as a colorless powder from mercury(II) acetate and diphenylphosphinic acid. Coordinating solvents were used to break the solid-state polymeric chains to allow the crystallization of new polymeric compounds. Crystallization from methylsulfoxide/methanol gave the solvent-free polymer catena-[Hg(μ2O2PPh2)] while pyridine/methanol gave the 1:2 Hg:pyridine adduct, catena-[Hg(μ2-O2PPh2)2(NC5H5)2] 3.1 and the molecular compound [Hg(O2PPh2)2(HO2PPh2)2(C5H5N)2] 3.2. In the centrosymmetric title compound [Hg(O2PPh2)2(HO2PPh2)2(C5H5N)2] 3.2, the approximately octahe9 dral Hg atom is coordinated by two each of phenylphosphinato, phosphinic acid and pyridine ligands. Each pair of phosphinic acid and phosphinato ligand features an intramolecular hydrogen bond to form an eight membered ring. The compounds 3 e 3.1, have a polymeric chain with two asymmetrically bridging diphenylphosphinate ligands. The latter also has two pyridine molecules coordinated to the Hg center. Bridged polymers, catena-[Pb(m2-O2PPh2)2{OCHN(CH3)2}2], 4.1, catena Pb(μ2-O2PPh2)2(NC5H5) 4.2, catena-[Pb(m2-O2PPh2)2(OS(CH3)2)2] 4.3 e [Pb(μ2-O2PPh2)2(4,4 -bipy)] 4.4 were synthesized by dissolving the polymeric [Pb(O2PPh2)2]n in coordination solvents; and, with slow evaporation, reforming the polymer in a well crystalline form of the solvent adduct, suitable for single crystal X-ray crystallography. The reaction of phenylphosphinic or diphenylphosphinic acid with cadmium(II) acetate produces respectively phenylphosphinate cadmium(II) or diphenylphosphinate cadmium(II), both insoluble polymeric compounds. The formation of adducts by dissolving these compounds in methanol in the presence of Lewis bases, such as pyridine, dimethylsulfoxide and dimethylformamide, breaks the polymeric chains. The slow evaporation formed crystals of [Cd(O2PHPh)2(OS(CH3)2)2]n 5.1 [Cd(O2PHPh)2(C5H5N)2] 5.2 [Cd(O2PPh2)2]n 6, [Cd(O2PPh2)2(C5H5N)2]n 6.1, [Cd(O2PPh2)2(OS(CH3)2)2]n 6.2 e [Cd(O2PPh2)2(OCHN(CH3)2)2] 6.3. The structures show one dimensional polymeric chains, formed by phosphinate ligands asymmetrically bridging.