Abstract
Reactions of mer, trans-$Re({\equiv}NC_6H_5)(PPh_3)_2Cl_3$, I, with $PMe_3$ and $P(OMe)_34 at room temperature, led to mer, trans-$Re({\equiv}NC_6H_5)(PPh_3)(PMe_3)Cl_3$, II, and fac-$Re({\equiv}NC_6H_5)(PPh_3)(P(OMe)_3)Cl_34, III, respectively. The crystal structures of II and III were determined through X-ray diffraction. Ⅱ crystallizes in the orthorhombic system, space group $Pna2_1$ with cell parameters a=19.379(4) ${\AA}$, b=11.867(2) ${\AA}$, c = 12.676(3) ${\AA}$, and Z = 4. Least-squares refinement of the structure led to a $R(wR_2)$ factor of 0.0251 (0.0621) for 2203 unique reflections of $I>2{\sigma}(I)$ and for 306 variables. III crystallizes in the monoclinic system, space group $P2_1/n$ with cell parameters a=11.399(3) ${\AA}$, b=14.718(4) ${\AA}$, c=17.558(5) ${\AA}$, ${\beta}=97.79(2){\circ}$, and Z=4. Least-squares refinement of the structure led to a $R(wR_2)$ factor of 0.0571 (0.1384) for 3739 unique reflections of $I>2{\sigma}(I)$ and for 344 variables. Structural studies showed that the relative orientations of the two phosphines in both complexes are different, probably due to the differences in the coordinating abilities between $PMe_3$ and $P(OMe)_3$ to the 5-coordinate fluxional intermediate.