STRUCTURAL DETERMINATIONS OF CHLOROBIS(TRIISOPROPYLPHOSPHINE)RHODIUM COMPOUNDS IN THE +2 AND +3 OXIDATION-STATES

The compounds [(i-Pr)3P]2RhCl2 (1), [(i-Pr)3P]2RhH2Cl (2), and [(i-Pr)3P]2RhHCl2 (3) have been crystallographically characterized. Compound 1: monoclinic, space group P2(1)/c, a = 8.127 (1) angstrom, b = 8.953 (2) angstrom, c = 16.189 (3) angstrom, beta = 92.52 (1)-degrees, R = 0.020, R(w) = 0.020. Compound 2: triclinic, space group P1BAR, a = 11.807 (2) angstrom, b = 14.681 (3) angstrom, c = 14.743 (3) angstrom, alpha = 111.66 (1)-degrees, beta = 92.18 (1)-degrees, gamma = 93.29 (1)-degrees, R = 0.026, R(w) = 0.027. Compound 3: monoclinic, space group P2(1)/c, a = 8.092 (1) angstrom, b = 8.961 (1) angstrom, c = 16.270 (3) angstrom, beta = 92.56 (1)-degrees, R = 0.020, R(w) = 0.026. All data were obtained at 173 K. Compounds 1, 3, and the previously-reported dinitrogen compound [(i-Pr)3P]2Rh(N2)Cl (4) are isostructural and allow a unique comparison of Rh-P and Rh-Cl bond distances among Rh(I), Rh(II), and Rh(III) oxidation states. From this isostructural series (compounds 1, 3, and 4) the Rh(I)-P distance is 2.348 (1) angstrom, the Rh(II)-P distance is 2.366 (1) angstrom, and the Rh(III)-P distance is 2.367 (1) angstrom; the Rh(II)-Cl distance is 2.298 (1) angstrom, and the Rh(III)-Cl distance is 2.324 (1) angstrom. The dihydrido chloro compound 2 resembles the earlier-reported compound [(t-Bu)3P]2RhH2Cl in that it has an acute H-Rh-H angle (65 (2), 66 (2)-degrees).