Assembling Homometallic Sb < inf > 6 < /inf > and Heterometallic Ti < inf > 4 < /inf > Sb < inf > 2 < /inf > Oxo Clusters

Abstract

Isolation and structural characterization of novel organoantimony(V)-based oxo clusters are reported. (RSb)4(OH)4(t-BuPO3)6 and (RSb)2(O)(t-BuPO3H)6 independently in the presence of pyridine under solvothermal conditions afford the hexanuclear organoantimonate clusters [(RSb)6(μ3-O)2(μ2-O)6(t-BuPO3)4], where R = p-i-PrC6H4 (1), p-ClC6H4 (2). Further, reaction of organostibonate phosphonate with Ti(OiPr)4 in the presence of pyridine under solvothermal conditions afforded the mixed-metal titanium stibonate hexanuclear clusters [(RSb)2Ti4(μ3-O)2(μ2-O)2(t-BuPO3)4(μ-OCH3)4(OCH3)4], where R = p-i-PrC6H4 (3), p-ClC6H4 (4). Band gap measurements were performed on 1â & circ;'4. They reveal a remarkable reduction in the band gap on moving from the heavier main-group-based oxo cages (1 and 2) to the titanium-incorporated oxo cages (3 and 4).