180848-47-9Relevant articles and documents
Synthesis and characterization of tungsten alkenyl-carbyne complexes [(dppe)(CO)2LW≡CCH=CCH2(CH2) nCH2CH2][BF4] (L = CO, MeCN, PMe3) and [(dppe)(CO)2XW≡CCH=CCH2(CH2]
Zhang, Lei,Gamasa, M. Pilar,Gimeno, José,Carbajo, Rodrigo J.,López-Ortiz, Fernando,Lanfranchi, Maurizio,Tiripicchio, Antonio
, p. 4274 - 4284 (2008/10/08)
Alkenyl-vinylidene complexes mer-[(dppe)(CO)3W=C=CHC=CH(CH2)nCH 2CH2] (dppe = 1,2-bis(diphenylphosphino)ethane; n = 1 (1a), n = 3 (1c), n = 4 (1d)) have been prepared by reaction of the complex fac-[(dppe)(CO)3W(Me2CO)] with 1-ethynylcyclopentanol, 1-ethynylcycloheptanol, and 1-ethynylcyclooctanol. Protonation at the Cδ of the alkenyl-vinylidene moiety with HBF4·OEt2 in diethyl ether or THF leads to the formation of cationic alkenyl-carbyne complexes mer-[(dppe)(CO)3W=CCH=CCH2(CH2) nCH2CH2][BF4] (n = 1 (2a), n = 3 (2c), n = 4 (2d)). When the protonation is carried out in CH2Cl2, isomeric carbyne complexes mer-[(dppe)(CO)3W≡CCH2C=CH(CH2) nCH2CH2][BF4] (2a′, 2c′, 2d′) are also generated. The alkenyl-carbyne complexes undergo carbonyl substitution by donor ligands to give dicarbonyl derivatives of the following types: (a) cationic complexes trans-[(dppe)(CO)2LW≡ CCH=CCH2(CH2)nCH2CH 2][BF4] (L = CH3CN, n = 1 (3a), n = 4 (3d); L = PMe3, n = 1 (4a), n = 4 (4d)) and (b) neutral complexes trans-[(dppe)(CO)2XW≡CCH=CCH2(CH2) nCH2CH2] (X = Cl, n = 1 (5a), n = 2 (5b), n = 3 (5c), n = 4 (5d); X = Br, n = 1 (6a), n = 4 (6d); X = I, n = 1 (7a), n = 3 (7c), n = 4 (7d)). The structure of complex 5a was determined by X-ray diffraction methods. The W atom displays a distorted octahedral coordination with the Cl atom [W-Cl = 2.540(1) A?] trans to the alkenyl-carbyne group [W≡C = 1.830(3) A?]. IR and 1H, 31P, 13C, and 183W NMR data are reported. The sequence for the trans influence in the order alkenyl-carbyne > alkenyl-vinylidene > CO could be found from the corresponding 1J(31P-183W) values. The low values for the alkenyl-carbyne groups are among the lowest ever reported, indicating a high trans influence of the carbyne group. 183W chemical shifts of compounds 1a-7a were obtained through two-dimensional indirect 31P, 183W recording techniques. A down field shifting of 183W resonances with decreasing π-acceptor ability of the ligands in complexes 2a-7a was observed.