SYNTHESIS AND STUDY OF PT(II)-NITRILE COMPLEXES - MULTINUCLEAR NMR-SPECTRA AND CRYSTAL-STRUCTURES OF COMPOUNDS OF THE TYPES [PT(R-CN)CL-3](-) AND CIS-PT(R-CN)(2)CL-2 AND TRANS-PT(R-CN)(2)CL-2

Complexes of the type [Pt(R-CN)Cl-3](-) were synthesized and studied b y H-1, C-13 and Pt-195 NMR spectroscopies. The (2)J(Pt-195-C-13) coupl ing constants are about 240 Hz. The signals due to the cyano carbon at oms of the coordinated ligands were observed at higher fields than tho se of the free ligands. The shielding on the cyano carbon increases as the alkyl chain lengthens and also when the branching increases. The Pt-195 signals of all the complexes were observed around -2000 ppm. Th e crystal structures of (NMe(4))[Pt(C3H7-CN)Cl-3] (1) and (NMe(4))[Pt( p-HO-C6H4-CN)Cl-3] (2) were determined. Compound 1 is monoclinic, P2(1 )/c, a = 8.384(5), b = 15.336(19), c = 11.759(9) Angstrom, beta = 99.5 2(6)degrees, Z = 4, R = 0.054, and wR = 0.051. Crystal 2 is tetragonal with a = 16.222(6), c = 12.052(5) Angstrom, Z = 8, R = 0.059, and wR = 0.044. The Pt-Cl bond trans to the nitrile ligand is shorter than no rmal (2.276(3) Angstrom for 1 and 2.264(7) Angstrom for 2) while the t wo other bends are normal (2.293(4), 2.287(3) Angstrom for 1 and 2320( 7), 2.275(8) Angstrom for 2). The Pt-N bonds are 1.97(1) Angstrom (1) and 1.92(2) Angstrom (2) and the segments Pt-N=C-C are linear. Disubst ituted compounds were also synthesized and studied by multinuclear NMR . The Pt-195 signals of the cis isomers were observed at lower fields than those of the trans isomers (Delta approximate to 65 ppm), while t he C-13 signals of the cyano carbons of the trans isomers were observe d at lower fields than those of the cia compounds (Delta approximate t o 0.6 ppm). The cis complexes isomerize to the trans compounds upon he ating. The crystal structures of cis-(3) and trans-Pt(C2H5-CN)(2)Cl-2 (4) and also of cis-Pt(p-HO-C6H4- CN)(2)Cl-2 (5) were determined. Crys tal 3 is monoclinic, P2(1)/c, a = 7.506(5), b = 9.539(5), c = 14.823(7 ) Angstrom, beta = 92.31(4)degrees, Z = 4, R = 0.050, and wR = 0.042. The trans isomer 4 is monoclinic with the Pt atom on an inversion cent re, P2(1)/c, a = 5.149(4), b = 9.394(8), c = 10.944(10) Angstrom, beta = 97.84(7)degrees, Z = 4, R = 0.017 and wR = 0.020. Finally, compound 5 is triclinic, P-1, a = 7.464(3), b = 10.712(6), c = 12.291(5) Angst rom, alpha = 75.63(4)degrees, beta = 75.63(4)degrees, gamma = 80.32(4) degrees, Z = 2, R = 0.045, and wR = 0.056. The Pt-Cl bond distances fo r the cis isomers are 2.269(5), 2.270(4) Angstrom for 3 and 2.274(2), 2.279(3) Angstrom for 5 while they are 2.289(3) Angstrom for the trans isomer (4). The Pt-N bonds are 1.962(14), 1.988(11) Angstrom (3), 1.97 2(7), 1.976(7)Angstrom (5) and 1.969(5) Angstrom for 4.