The Weak Metal–Water Bond in Diphenylborylated Organoaquacobaloximes and Rhodoximes Leads to the Formation of an Unusual Dinuclear Rh(III) Complex*

The synthesis and characterization of a series of RM(DBPh2)2(H2O) complexes (M = Co and Rh) and the X-ray structure of the dinuclear n-PrRh(DH)(DBPh2) 2 (1) obtained by recrystallization of nPrRh(DBPh2)2(H2O) in non coordinating solvent are reported. The crystals of (1) are built up by neutral centrosymmetric dinuclear n-PrRh(DH)(DBPh2) 2 units and CH2Cl2 crystallization molecules in the ratio 1:1. The Rh ion of one n-PrRh(DH)(DBPh2) unit achieves hexacoordination by coordination of one of the oxime O atoms of the other unit. The formation of the dimer by recrystallization of n-PrRh(DBPh2)2(H2O) in non coordinating solvent may be ascribed to the concomitant effect of the weak metal–water bond in the monomeric aqua complex, the strong tendency of Rh to achieving hexacoordination in such organo derivatives, and the ease of losing a BPh2 bridge of the diphenylborylated organorhodoximes.