The reaction of [WBr2(CO)2(nbd)] 1 (nbd = norbornadiene) with Tl(C5H5) gave a monocarbonyl deriv. [WBr(CO)(nbd)(η5-C5H5)] 2. With Tl(O2CMe) and Tl[O(S)CMe], complex 1 gave monosubstituted derivs. [WBr(O2CMe)(CO)2(nbd)] 3a and [WBr{O(S)CMe}(CO)2(nbd)] 3b which appear to be seven-coordinate according to IR data. In contrast 1 and Tl(SC6F5) (1:1 molar ratio) gave the six-coordinate complex [WBr(SC6F5)(CO)2(nbd)] 4. An x-ray diffraction study of 4 established that it has a distorted-octahedral structure with trans W-CO bonds approx. perpendicular to a plane contg. the W, Br and S atoms and the midpoints of the nbd C:C bonds. Simple electronic arguments provide a rationalization of many of the structural features of 4. Reaction of 1 with 2 molar equivalents of Tl(SC6F5) gave the bis(thiolate) deriv. [W(SC6F5)(CO)2(nbd)] 5 again with a trans arrangement of CO ligands. The reactions of 5 with L = PEt3, PMe2Ph or P(OMe)3 gave the six-coordinate complexes [W(SC6F5)2(CO)2L2] 6 which exist in two isomeric forms, red or green. Dynamic NMR studies have been used to characterize the isomeric behavior and fluxional processes in the complexes.
Synthesis and reactions of tungsten(II) norbornadiene (nbd) complexes. The crystal and molecular structure of [WBr(SC6F5)(CO)2(nbd)]
VASAPOLLO, Giuseppe;
1993-01-01
Abstract
The reaction of [WBr2(CO)2(nbd)] 1 (nbd = norbornadiene) with Tl(C5H5) gave a monocarbonyl deriv. [WBr(CO)(nbd)(η5-C5H5)] 2. With Tl(O2CMe) and Tl[O(S)CMe], complex 1 gave monosubstituted derivs. [WBr(O2CMe)(CO)2(nbd)] 3a and [WBr{O(S)CMe}(CO)2(nbd)] 3b which appear to be seven-coordinate according to IR data. In contrast 1 and Tl(SC6F5) (1:1 molar ratio) gave the six-coordinate complex [WBr(SC6F5)(CO)2(nbd)] 4. An x-ray diffraction study of 4 established that it has a distorted-octahedral structure with trans W-CO bonds approx. perpendicular to a plane contg. the W, Br and S atoms and the midpoints of the nbd C:C bonds. Simple electronic arguments provide a rationalization of many of the structural features of 4. Reaction of 1 with 2 molar equivalents of Tl(SC6F5) gave the bis(thiolate) deriv. [W(SC6F5)(CO)2(nbd)] 5 again with a trans arrangement of CO ligands. The reactions of 5 with L = PEt3, PMe2Ph or P(OMe)3 gave the six-coordinate complexes [W(SC6F5)2(CO)2L2] 6 which exist in two isomeric forms, red or green. Dynamic NMR studies have been used to characterize the isomeric behavior and fluxional processes in the complexes.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
