TY - JOUR
T1 - Co-ordinatively unsaturated diene complexes of tungsten(II) and their reactions with nucleophilesto give six- and seven-co-ordinate derivatives
AU - Davidson, Jack L.
AU - Vasapollo, Guiseppe
PY - 1985
Y1 - 1985
N2 - [{WBr2(CO)4}2] reacts with the 'dienes' (L') cyclo-octa-1,5-diene (cod), cyclo-octatetraene (cot), and norbornadiene (bicyclo[2.2.1] hepta-2,5-diene, nbd) to give co-ordinatively unsaturated complexes [WBr2(CO)2L']. These react with Lewis bases L [= CNBut, PMe2Ph, or P(OMe)3] (1:1 molar ratio) to give co-ordinatively unsaturated diene complexes [WBr2(CO)LL'] via intermediate 1:1 adducts [WBr2(CO)2LL'] isolated in the case of the norbornadiene complexes. With a 3:1 molar ratio of ligand:metal, displacement of cod or cot occurs to give [WBr2(CO)2L3] [L = P(OMe)3, PMe2Ph, or CNBut], while a 4:1 molar ratio (L = CNBut) gives [WBr2(CO)(CNBut)4]. In contrast, [WBr2(CO)2(nbd)] forms monocarbonyl diene complexes [WBr2(CO) L2(nbd)] [L = P(OMe)3 or PMe2Ph, L2 = 2,2'-bipyridyl]. Proton and 31P n.m.r. studies of [WBr2(CO)2L3] [L = P(OMe)3 or PMe2Ph] reveal the presence of two isomeric forms which exhibit dynamic stereochemistry at ambient temperature while the static form of one isomer could be detected at lower temperatures.
AB - [{WBr2(CO)4}2] reacts with the 'dienes' (L') cyclo-octa-1,5-diene (cod), cyclo-octatetraene (cot), and norbornadiene (bicyclo[2.2.1] hepta-2,5-diene, nbd) to give co-ordinatively unsaturated complexes [WBr2(CO)2L']. These react with Lewis bases L [= CNBut, PMe2Ph, or P(OMe)3] (1:1 molar ratio) to give co-ordinatively unsaturated diene complexes [WBr2(CO)LL'] via intermediate 1:1 adducts [WBr2(CO)2LL'] isolated in the case of the norbornadiene complexes. With a 3:1 molar ratio of ligand:metal, displacement of cod or cot occurs to give [WBr2(CO)2L3] [L = P(OMe)3, PMe2Ph, or CNBut], while a 4:1 molar ratio (L = CNBut) gives [WBr2(CO)(CNBut)4]. In contrast, [WBr2(CO)2(nbd)] forms monocarbonyl diene complexes [WBr2(CO) L2(nbd)] [L = P(OMe)3 or PMe2Ph, L2 = 2,2'-bipyridyl]. Proton and 31P n.m.r. studies of [WBr2(CO)2L3] [L = P(OMe)3 or PMe2Ph] reveal the presence of two isomeric forms which exhibit dynamic stereochemistry at ambient temperature while the static form of one isomer could be detected at lower temperatures.
UR - http://www.scopus.com/inward/record.url?scp=37049101112&partnerID=8YFLogxK
U2 - 10.1039/DT9850002231
DO - 10.1039/DT9850002231
M3 - Article
SN - 1472-7773
SP - 2231
EP - 2238
JO - Journal of the Chemical Society, Dalton Transactions
JF - Journal of the Chemical Society, Dalton Transactions
IS - 11
ER -