Preparation and Characterization of [RhCl2(edpp)2]+ (edpp=(2-aminoethyl)diphenylphosphine). Crystal Structures of <i>trans</i>(Cl,Cl), <i>cis</i>(P,P)-[RhCl2(edpp)2]Cl·2C2H5OH and <i>cis</i>(Cl,Cl), <i>trans</i>(P,P)-[RhCl2(edpp)2]Cl·4H2O

Abstract

Abstract Two of the five possible geometrical isomers of [RhCl2(edpp)2]+ were formed by reaction of RhCl3·2H2O with edpp (edpp=(2-aminoethyl)diphenylphosphine) in 1:2 molar ratio in ethanol. The chlorides of the isomers were separated by fractional crystallization from ethanol. The structures of the more soluble (main product) and the less soluble (minor product) complexes were determined by X-ray analyses to have the trans(Cl,Cl), cis(P,P) and cis(Cl,Cl), trans(P,P) configurations, respectively. Crystal data are: for trans(Cl,Cl), cis(P,P)-[RhCl2(edpp)2]Cl·2C2H5OH, triclinic, space group P\bar1, with a=10.024(3), b=18.865(3), c=9.833(2) Å, α=97.66(1), β=103.92(2), γ=82.30(2)°, and Z=2, and for cis(Cl,Cl), trans(P,P)-[RhCl2(edpp)2]Cl·4H2O, triclinic, space group P\bar1, with a=11.341(4), b=17.780(6), c=8.712(3) Å, α=95.60(4), β=112.31(3), γ=82.56(4)°, and Z=2. The trans influence of the P atom on the Rh–N and Rh–P bond lengths is observed. The mean Rh–N and Rh–P bond lengths (2.125(4) and 2.300(1)Å) in the trans(Cl,Cl), cis(P,P) isomer are respectively longer and shorter than those of the cis(Cl,Cl), trans(P,P) isomer (2.078(12) and 2.336(3)Å). 13C NMR and absorption spectra of the isomers were recorded and are discussed.