CARBONYL DERIVATIVES OF CHLORIDE DIMETHYL-SULFOXIDE RUTHENIUM(II) COMPLEXES - SYNTHESIS, STRUCTURAL CHARACTERIZATION, AND REACTIVITY OF RU(CO)(X)(DMSO)(4-X)CL-2 COMPLEXES (X=1-3)

The reactivity of cis- and trans-RuCl2(DMSO)(4) with carbon monoxide h as been thoroughly investigated. Depending on the choice of the solven t and the reaction conditions, cis-RuCl2(DMSO)(4) reacts with CO at am bient pressure replacing one, two or three DMSO molecules. The followi ng derivatives have been isolated: trans,cis,cis-Ru-(CO)(DMSO)(DMSO)(2 )Cl-2 (1), cis,cis,cis-Ru(CO)(2)(DMSO)(DMSO)Cl-2 (2), cis,trans,cis-Ru (CO)(2)(DMSO)(2)Cl-2 (3) and fac-Ru(CO)(3)(DMSO)Cl-2 (4). Compounds 1, 3 and 4 have been structurally characterized. 1 . 0.5H(2)O: monoclini c, P2(1)/c, Z = 8, a = 15.408(1) Angstrom, b = 15.398(2) Angstrom, c = 14.826(1) Angstrom, beta = 107.46(1)degrees. 3: orthorhombic, Pca2(1) , Z = 8, a = 15.853(3) Angstrom, b = 11.380(2) Angstrom, c = 14.874(2) Angstrom. 4: orthorhombic, P2(1)2(1)2(1), Z = 4, a = 7.300(2) Angstro m, b = 9.297(2) Angstrom, c = 16.515(4) Angstrom, beta = 107.46(1)degr ees. Reaction of trans-RuCl2(DMSO)(4) with CO at room temperature and ambient pressure leads to the replacement of either one or two DMSO li gands, depending on the reaction time, yielding trans,trans,trans-Ru(C O)(DMSO)(DMSO)(2)Cl-2 (5) and cis,cis,trans-Ru(CO)(2)(DMSO)(2)Cl-2 (6) . The crystal structure of 5 has been determined. 5: monoclinic, P2(1) , Z = 4, a = 7.417(3) Angstrom, b = 26.808(6) Angstrom, c = 8.368(4) A ngstrom, beta = 107.55(7)degrees. Complex 3 is the thermodynamically m ost stable bis(carbonyl) species. Compounds 1-6 represent the first ex ample of well-characterized Ru(II) chloride-DMSO-carbonyl complexes. T heir most striking common feature is that coordination of carbon monox ide induces the selective isomerization of the DMSO trans to it from S - to O-bonding. Compounds 1-6 are versatile precursors for the synthes is of carbonylated Ru(II) species in which the DMSO ligands are partia lly or completely replaced by other ligands. Reaction of 1-6 with pyri dine has been investigated and several products were isolated. The rea ctions were often accompanied by a geometrical isomerization. Complex 1 yields cis,cis,cis-Ru(CO)(py)-(DMSO)(2)Cl-2 (7), whose crystal struc ture has been determined. 7: triclinic, P $($) over bar$$ 1, Z = 2, a = 7.129(3) Angstrom, b = 7.918(2) Angstrom, c = 14.516(7) Angstrom, al pha = 84.70(3)degrees, beta = 88.14(3)degrees, gamma = 77.87(3)degrees . Complex 3 can replace either one DMSO ligand, forming the two geomet rical isomers cis,cis,cis-Ru(CO)(2)(py)(DMSO)Cl-2 (8) and cis,trans,ci s-Ru-(CO)(2)(py)(DMSO)Cl-2 (9), or two DMSO ligands, yielding cis,cis, trans-Ru(CO)(2)(py)(2)Cl-2 (10), where a cis to trans isomerization of the two chlorides occurred. Also the crystal structure of 9 has been determined; 9: triclinic, P $($) over bar$$ 1, Z = 4, a = 7.939(3) Ang strom, b = 12.863(5) Angstrom, c = 14.133(3) Angstrom, alpha = 105.95( 2)degrees, beta = 95.10(2)degrees, gamma = 99.02(2)degrees. fac-Ru(CO) (3)(py)Cl-2 (11) was obtained from 4, while cis,cis,trans-Ru(CO)(DMSO) (py)(2)Cl-2 (12) and cis,cis,trans-Ru(CO)(2)(py)(2)Cl-2 (10) were synt hesized from 5 and 6, respectively.