Some new rhodium(I)-iridium(III) complexes with bridging hydride and chloride ligands. Synthesis of compounds [L2Rh(.mu.-H)(.mu.-Cl)IrH2L'2] (L = PEt3 or L2 = diphos; L' = PEt3, P-iso-Pr3) and the x-ray crystal structure of [(PEt3)2Rh(.mu.-H)(.mu.-Cl)IrH2(PEt3)2]