Organometallics ,J(PtHe) = 30 Hz, He], 8.98 [d, br, 2 H, 3J(PtHa) = 13 Hz, Ha]; second isomer, 6 1.44 [s, 6 H, 3J(PtH) = 71 Hz, Mea or MebPt], 1.20 [s, 6 H, 3J(PtH) = 72 Hz, Me or MebPt], 0.68 [s, 6 H, 3J(PtH) = 72 Hz, MecPt], 9.43 [s, br, 2 H, ,J(PtHe) = 30 Hz, He]; the signalfor Ha is superimposed with the signal for Ha listed above. The spectrum containing both isomers 19b also have multiplets due to HW between 7.81 and 8.29 ppm and due to the nonequivalent methylene protons at 4.55-4.87 ppm.[PtMez(pyox)] (23). To a solution of pyox (0.103 g) in CHzClz (5 mL) was added 0.5 equiv of [PhMe4(&Mez)z] (0.132 g) as a CH2C12 (10 mL) solution. The solution immediately turned dark orange, and on standing for 1 h some of the prodduct precipitated from solution. The solvent was removed, and the orange product was washed with diethyl ether and dried under vacuum: yield 97%; mp 186 "C dec. Anal. Calcd for Cl4HI4N40Pt: C, 37.4; H, 3.1; N, 12.5. Found: C, 37.3; H, 2.9; N, 12.1. lH NMR (CD2Clz) 6 1.03 [s, 3 H, ?-J(PtH) = 92 Hz, MeaPt], 1.03 ppm [s, 3 H, 2J(PtH) = 90 Hz, MebPt], 9.20 [d, br, 1 H, ,J(PtH) = 19.5 Hz, ,J(HaHb) = 6 Hz, Ha], 8.82 [ddd, 1 H, 3J(HhHg) = 6 Hz, 4J(HhH9 = 3 Hz, 'J(HhHe) = 1 Hz, Hh], 7.54-8.42 [m, 6 H, HW, Hq]; the labels Mea and Meb may be interchanged. [PtIMe3(pyox)] (24). To a solution of [PtMez(pyox)] (0.063 g) in CHzClz (15 mL) was added an excess of Me1 (0.5 mL). The orange solution immediately turned bright yellow, and after 0.5 h the solvent was removed. The solid yellow product was washed with n-pentane and dried under vacuum: yield, quantitative ; mp 237 "C dec. Anal. Calcd for CI5Hl7H4OIPt: C, 30.5; H, 2.9; N, 9.5. Found: C, 30:l; H, 2.9; N, 9.3. ' H NMR (CD2C12): 6 1.771986,5, 2529-2537 2529 [e., 3 H, 2J(PtH) = 76 Hz, Meapt], 1.57 [s, 3 H, zJ(PtH) = 72 Hz, MebPt], 0.79 [s, 3 H, V(PtH) = 72 Hz, MecPt], 9.00 [d, br, 1 H, ,J(PtH) = 14 Hz, 3J(HaHb) = 6 Hz, Ha], 8.83 [d, br, 1 H, ,J(HhHg) = 6 Hz, Hh], 7.55-8.47 [m, 6 H, HW, Hw]; the assignments Mea and Meb may be reversed. [PtzMe4(pazpy)] (25).To a solution of azpy (0.026 g) in acetone (10 mL) was added 1 equiv of [PhMe4(pSMez)z] (0.080 g) as an acetone solution (15 mL). The solution immediately turned dark brown, and the product precipitated from solution over 1 h. The brow solid product was collected by filtration, washed with acetone, and dried under vacuum: yield 94%; mp 205 "C dec. Anal. Calcd for C14Hd4P&: C, 26.5; H, 3.2; N, 8.8. Found: C, 27.0; H, 3.6; N, 8.8. This complex is insoluble in all common organic solvents. Attempts to prepare the mononuclear [PtMez(azpy)] were unsuccessful. Acknowledgment. We thank NSERC (Canada) for financial support.
Registry No.The results of solution calorimetric studies are used to measure the relative stability in solution of the following complexes: (arene)Mo(CO), (arene = o-xylene, rn-xylene, p-xylene, NJV-dimethylaniline, pbis(dimethylamino)benzene, (trimethylsilyl)benzene, sodium tetraphenylborate, and sodium cyclopentadiene), L,Mo(CO), (L = acetone, acetonitrile, benzonitrile, tert-butyl cyanide, tert...
