Canadian Journal of Chemistry p. 2289 - 2303 (1996)
Update date:2022-09-26
Topics:
George, Darren S.A.
McDonald, Robert
Cowie, Martin
The reaction of [Ir2(CO)3(dppm)2] (dppm = Ph2PCH2PPh2) with dimethyl acetylenedicarboxylate (DMAD) first yields [Ir2(CO)2(μ-η1:η 1-DMAD)(dppm)2] (2) in which the alkyne is bound parallel to the metal-metal axis and the diphosphines are bound in a trans arrangement at both metals. This metastable isomer slowly rearranges to the stable form, [Ir2(CO)2(μ-η2:η 2-DMAD)(dppm)2] (3), in which the alkyne is now bound perpendicular to the metals and the diphosphines are bent back in a cis arrangement at both metals. The analogous species can be prepared by substituting hexafluoro-2-butyne (HFB) for DMAD; however, for the HFB adduct the isomer having the parallel geometry is seen only as a transient species; only [Ir2(CO)2(μ-η2:η 2-HFB)(dppm)2] (5) was isolated. Compound 2 reacts readily with PMe3 to yield [Ir2(CO)(PMe3)(μ-CO)(μ-η1:η 1-DMAD)(dPPm)2], and with CH3OSO2CF3 to yield [Ir2(CH3)(CO)2(μ-η 1:η1-DMAD)(dppm)2][SO3CF 3], whereas 3 reacts with neither reagent. Both 2 and 3 react with HBF4·OEt2 to yield the respective alkyne-bridged hydrides, [Ir2H(CO)2(μ-η1:η 1-DMAD)(dppm)2][BF4] and [Ir2H(CO)2(μ-η2:η 2-DMAD)(dppm)2][BF4], in which the gross structural features and the alkyne coordination mode of the precursor are retained in each case. The latter species rearranges readily at ambient temperature, via migratory insertion, to give the vinyl-bridged product, [Ir2(CO)2(μ-η1:η2-RC = C(H)R)(dppm)2][BF4] (R = CO2Me); however, the former is inert under these conditions, yielding the above vinyl species together with other decomposition products only upon reflux in benzene for several hours. Protonation of the perpendicular hexafluoro-2-butyne adduct also yields the corresponding vinyl product, together with decomposition products. The structure of 3, as the methylene chloride disolvate, was established by X-ray analysis. Crystal data are as follows. 3·2CH2Cl2: C60H54Cl4O6P4Ir 2, monoclinic, P2/c, a = 26.088(5) A, b = 9.896(4) A, c = 23.954(3) A, β = 109.27(1)°, Z = 4, R(F) = 0.038, Rw(F2) = 0.0997 (all data).
View MoreHubei Danao Pharmaceutical Co.,Ltd.
website:http://www.danaopharm.com
Contact:+86-719-5251167
Address:Fandan Road,Danjiangkou,Hubei
Sichuan Sangao Biochemical Co., Ltd
Contact:+86-28-84874233
Address:19F, Bldg.2, Shudu Center, Tianfu 2nd St., Hi-tech zone, Chengdu 610041, Sichuan Province, China.
Qingdao XinYongAn Chemicals Co., Ltd
Contact:+86-532-81107967
Address:Chengyang dual-port industrial park by the sea,Qingdao
Wuxi Morality Chemical Co., Ltd(expird)
Contact:
Address:B/7F, 321th WuYun Rd, Wanda Plaza, Wuxi City, 214174, China
Contact:0027-717-456976
Address:2ND FLOOR, 325 VAUSE ROAD, OVERPORT, 4001, SOUTH AFRICA
Doi:10.1002/jhet.5570330674
(1996)Doi:10.1002/jhet.5570330606
(1996)Doi:10.1021/ac00254a034
(1983)Doi:10.1016/S0040-4020(02)00096-0
(2002)Doi:10.1021/ja963036t
(1997)Doi:10.1007/BF00909814
()