Structural Features of d2-Rhenium(V) Monomeric Octahedral Dioxocomplexes with Tridentate-Chelate, Monodentate Ligands [ReO2(Ltri)(Lmono)], and Tetradentate-Chelate Ligands [ReO2(Ltetra)] (A Review)

Abstract

Molecular geometry features of 21 structurally characterized mononuclear octahedral dioxocomplexes of d2-rhenium(V) with mono-, tri- and tetradentate ligands [ReO2(Ltri)(Lmono)], [ReO2(Ltetra)] are discussed. In eleven cases, multiple-bonded Ooxo ligands are arranged in trans-positions to each other with OoxoReOoxo angles ranging within 172.9–180°. In ten structures, the ReO2 unit adopts cis-configuration with OoxoReOoxo angles vary within 106.7–124.8°. Re atoms possess either trans-octahedral coordination environment ReOoxo2X4 (X = N, P, As, O) or cis-structure ReOoxo2N2O2. Bonds Re=Ooxo in monomeric octahedral dioxocompounds d2-Re(V) (mean length 1.772 Å) are significantly longer those observed for monooxocomplexes d2-Re(V) (1.676–1.699 Å).