SYNTHESIS AND CHARACTERIZATION OF HOMO- AND HETEROMETALLIC GERMANIUM (IV) COORDINATION COMPOUNDS WITH MALIC ACID AND HETEROCYCLIC AMINES

Abstract

The mixed-ligand [Ge(HMal)2(bipy)]·bipy·2H2O (1) and mixed-ligand-heterometallic [Ni(phen)3][Ge(OH)(HMal)2]2·12H2O (2), [Ni(bipy)3][Ge(OH)(HMal)2]2·12H2O (3) germanium complexes with malic acid (H3Mal) and heterocyclic amines 2,2'-bipyridine (bipy), 1,10-phenanthroline (phen) were obtained for the first time. It was established that in the IR-spectra of 1-3 stretching vibrations of aromatic rings n(C-CАr) ~ 1598-1493 cm-1, ν(C-N) ~ 1315 cm-1, ν(C-N) ~ 1315сm-1, and also n(Ge-N) = 655 сm-1 (for 1), n(Ni-N) = 420 сm-1 (for 2, 3) are presented. This evidences about the presence of bipy or phen in the molecules of compounds. The absorption bands n(C=O) ~ 1708 сm-1, νas(СOО-) ~ 1671 сm-1, νs(СOО-) ~ 1448 сm-1 are specific for the vacant carboxylic and monodentate protonated carboxylate groups (Dn = νas(СOО-) – νs(СOО-) ~ 220 сm-1). The absorption bands ν(C-O) ~ 1130 сm-1 of the alcoholic group ν(Ge-O) ~ 778-725 сm-1 have been also detected in the IR-spectra of 1-3. The feature of heterometalic complexes 2, 3 is presence of deformation vibrations band of the bond Ge-O-Н ~ 855 сm-1. In the mass-spectra of anions 2 and 3 the formation of same fragmentation ions [Ge(OH)(HMal)]·H2O and [Ge(HMal)2] with m/z ~ 243 and 337. In the compounds 1-3 malic acid coordinates in the monoprotonated form, one hydroxyl and one carboxyl groups take part in the formation of bonds with Ge(IV) atom, the second carboxyl group stays vacant. In the complex 1 the octahedral coordination polyhedron of Ge is formed through the bidentate coordination of 2,2'-bipyridine (bipy). Complexes 2,3 are of cationanionic type with the electrostatic interaction between their cations and anions. In 2,3 Germanium has coordination number 5 and saturates its coordination sphere by binding to the OH-group, and as the result similar complex anion with the composition [Ge(OH)(HMal)2]- is formed. Cations [Ni(bipy/рhen)3]2+ are formed through the coordination three molecules of 2,2'-bipyridine (bipy), 1,10-phenanthroline (phen) by nickel atom.The mixed-ligand [Ge(HMal)2(bipy)]·bipy·2H2O (1) and mixed-ligand-heterometallic [Ni(phen)3][Ge(OH)(HMal)2]2·12H2O (2), [Ni(bipy)3][Ge(OH)(HMal)2]2·12H2O (3) germanium complexes with malic acid (H3Mal) and heterocyclic amines 2,2'-bipyridine (bipy), 1,10-phenanthroline (phen) were obtained for the first time. It was established that in the IR-spectra of 1-3 stretching vibrations of aromatic rings n(C-CАr) ~ 1598-1493 cm-1, ν(C-N) ~ 1315 cm-1, ν(C-N) ~ 1315сm-1, and also n(Ge-N) = 655 сm-1 (for 1), n(Ni-N) = 420 сm-1 (for 2, 3) are presented. This evidences about the presence of bipy or phen in the molecules of compounds. The absorption bands n(C=O) ~ 1708 сm-1, νas(СOО-) ~ 1671 сm-1, νs(СOО-) ~ 1448 сm-1 are specific for the vacant carboxylic and monodentate protonated carboxylate groups (Dn = νas(СOО-) – νs(СOО-) ~ 220 сm-1). The absorption bands ν(C-O) ~ 1130 сm-1 of the alcoholic group ν(Ge-O) ~ 778-725 сm-1 have been also detected in the IR-spectra of 1-3. The feature of heterometalic complexes 2, 3 is presence of deformation vibrations band of the bond Ge-O-Н ~ 855 сm-1. In the mass-spectra of anions 2 and 3 the formation of same fragmentation ions [Ge(OH)(HMal)]·H2O and [Ge(HMal)2] with m/z ~ 243 and 337. In the compounds 1-3 malic acid coordinates in the monoprotonated form, one hydroxyl and one carboxyl groups take part in the formation of bonds with Ge(IV) atom, the second carboxyl group stays vacant. In the complex 1 the octahedral coordination polyhedron of Ge is formed through the bidentate coordination of 2,2'-bipyridine (bipy). Complexes 2,3 are of cationanionic type with the electrostatic interaction between their cations and anions. In 2,3 Germanium has coordination number 5 and saturates its coordination sphere by binding to the OH-group, and as the result similar complex anion with the composition [Ge(OH)(HMal)2]- is formed. Cations [Ni(bipy/рhen)3]2+ are formed through the coordination three molecules of 2,2'-bipyridine (bipy), 1,10-phenanthroline (phen) by nickel atom.

Keywords

• германій
• нікель
• яблучна кислота
• 1,10-фенантролін
• 2,2'-біпіридин
• координаційні сполуки