Preparation and Characterization of Rhodium(III) Complexes Containing (2-Aminoethyl)dimethylphosphine (edmp) or 1,2-Bis(dimethylphosphino)ethane (dmpe). Structures of <i>fac</i>-[Rh(edmp)3]3+, <i>trans</i>(<i>Cl</i>,<i>Cl</i>),<i>cis</i>(<i>P</i>,<i>P</i>)-[RhCl2(edmp)2]+, and <i>trans</i>-[RhCl2(dmpe)2]+

Abstract

Abstract The fac-[Rh(edmp)3]3+ (edmp=(2-aminoethyl)dimethylphosphine), trans(Cl,Cl),cis(P,P)-[RhCl2(edmp)2]+, and trans-[RhCl2(dmpe)2]+ (dmpe=1,2-bis(dimethylphosphino)ethane) complexes were prepared and the molecular structures were determined by the single crystal X-ray diffraction method. Crystal data and final R values are: fac-[Rh(edmp)3]Br3·3H2O, orthorhombic, Pna21, a=26.750(4), b=10.125(1), c=9.592(1) Å, V=2598.2(5) Å3, Z=4, R=0.039 for 1590 observed unique reflections. trans(Cl,Cl),cis(P,P)-[RhCl2(edmp)2]PF6, monoclinic, P21/a, a=18.197(4), b=12.574(2), c=8.615(1) Å, β=96.59(2)°, V=1958.2(6) Å3, Z=4, R=0.032 for 3379 reflections. trans(Cl,Cl),cis(P,P)-[RhCl2(edmp)2]ClO4, triclinic, P\bar1, a=13.122(2), b=17.952(2), c=12.343(2) Å, α=91.65(2), β=102.46(2), γ=80.74(1)°, V=2802.0(7) Å3, Z=6, R=0.070 for 7513 reflections, trans-[RhCl2(dmpe)2]CF3SO3, monoclinic, P21/a, a=13.166(2), b=24.337(4), c=8.002(2) Å, β=95.95(2)°, V=2550.1(8) Å3, Z=4, R=0.040 for 3201 reflections. It was found that the shorter the Rh–P bond length, the larger the trans Rh–N bond elongation. The mean Rh–P bond distance in trans-[RhCl2(dmpe)2]CF3SO3 (2.337(2) Å) is longer than those in fac-[Rh(edmp)3]Br3·3H2O (2.283(4) Å) and trans(Cl,Cl),cis(P,P)-[RhCl2(edmp)2]PF6 (2.252(2) Å). A series of complexes of trans(X,X),cis(P,P)-[RhX2(edmp)2]+ (X=Cl, Br, I) and trans-[RhX2(dmpe)2]+ (X=Cl, Br) were also prepared and their absorption spectra were compared with one another and with those of the corresponding cobalt(III) complexes.