STRUCTURAL AND MECHANISTIC INVESTIGATION PROBING LIGAND SUBSTITUTION OF HW2(CO)9(NO)

Syntheses of HW2(CO)8(P(p-C6H4X)3)(NO) (1, X = Me; 3, X = OMe; 5, X = F), HW2(CO)7(P(p-C6H4X)3)2-(NO) (2, X = Me; 4, X = OMe; 6, X = F), HW2(CO)8(AsPh3)(NO) (7), [NMe4][HW2(CO)7(eta2-S2CR2)(NO)] (8, R2 = Et2; 9, R2 = -CH2(CH2)2CH2), and HW2(CO)7(L)2(NO) (10 (isomers I and II), L = py (pyridine); 11 (isomers I and II), L = bipy (2,2'-bipyridine)) from either HW2(CO)9(NO) or HW2(CO)7(THF)2(NO) are reported. IR and H-1, P-31, and N-15 NMR spectral studies are used as probes for mechanistic insight into the reactions with phosphines. Both HW2(CO)9(NO) and HW2(CO)7(THF)2(NO) follow mainly a dissociative pathway with subsequent rearrangement of the NO ligand. X-ray crystal structural analyses for 5, 6, 10 (isomer I), and 11 (isomer I) were carried out, yielding the following data. 5: triclinic; P1BAR; Z = 2; a = 9.1656 (7), b = 10.791 (1), c = 15.442 (1) angstrom; alpha = 97.73 (1), beta = 76.21 (1), gamma = 104.290 (6)-degrees; V = 1432.8 (2) angstrom3; R = 0.021; R(w) = 0.026. 6: triclinic; P1BAR; Z = 2; a = 10.116 (1), b = 11.387 (1), c = 19.342 (2) angstrom; alpha = 95.91 (1), beta = 98.53 (1), gamma = 106.70 (1)-degrees; V = 2085.5 (3) angstrom3; R = 0.023; R(w) = 0.026. 10 (isomer 1): monoclinic; P2(1)/c; Z = 4; a = 9,865 (1), b = 10.6616 (8), c = 20.610 (1) angstrom; beta = 90.744 (7)-degrees; V = 2167.5 (3) angstrom3; R = 0.025; R(w) = 0.029. 11 (isomer I): monoclinic; C2/c; Z = 8; a = 20.872 (2), b = 10.5217 (9), c = 19.095 (3) angstrom; beta = 100.12 (1)-degrees; V = 4128.2 (8) angstrom3; R = 0.025; R(w) = 0.028.