Pathways for carbon–chain growth reactions at a dimolybdenum centre

Abstract

Reaction of [ M o ~( C O ) ~( T ~X ~H ~) ~] with MeC2Me forms, via competitive reaction paths, the dinuclear complexes [Mo*(p-MeC2Me)(CO)4(r15-CgH7)21 and [ M ~~{ C L -( ~, ~-~~-C ~M ~~) } ( C O ) ~( ~~-C ~H ~~( ~-C ~H ~) I ; the latter on heating decarbonylates to give [ M O ~{ ~-( U , ~-~~-C ~M ~~) } ( ~-C O ) ( ~~-C ~H ~) ~~, which reacts with MeC2Me to form the 'fly-over' complex [Mo2{ p-(a,y3 : q3,a-C6Me6)} (q5-C&)21.

Light-Induced Codimerisation of Acetylene and Olefins at a Binuclear Tungsten Complex

“…In (CO) 6 [Mo 2 (η 5 -C 5 H 4 CH 3 ) 2 (CO) 2 (µ-η 4 -butadiene)] [13] . In the case bonylbis(η 5 -cyclopentadienyl)dichromium and the related compounds with all four CO ligands inclined to the adja-of the photoreaction of [W 2 (η 5 -C 5 H 4 CH 3 ) 2 (CO) 6 ] with 1,3butadiene the only isolable product is [W 2 (η 5 -cent metal centres, in complex 7 only two of them show this C 5 H 4 CH 3 ) 2 (CO) 4 {µ-η 1:3 -(E)-2-butene-1,1-diyl}], [18] the diene yields the analogous 2-butene-1,1-diyl complex [18] . 1,3-Metalladiene complexes may adopt s-cis [30] [41] or s-trans analogue to 4A.…”

“…The isolated products give good evidence for the route of one of the products of the photoreaction of 1 with A is the photochemical reaction when (µ-η 2:2 -acetylene)tetracar-[Mo 2 (η 5 -C 5 H 4 CH 3 ) 2 (CO) 3 (H)(η 1:4 -1,3-cycloheptadien-1-yl)], bonylbis(η 5 -cyclopentadienyl)ditungsten(WϪW) (1) is irwhich is obtained when [Mo 2 (η 5 -C 5 H 4 CH 3 ) 2 (CO) 4 ] is irradiated in the presence of olefins. In a primary step one radiated in presence of 1,3-cycloheptadiene.…”

“…Binuclear Preparative Results complexes offer after a suitable activation the possibility for The photoreaction of (µ-η 2:2 -acetylene)tetracara simultaneous coordination of two alkenes or alkynes folbonylbis(η 5 -cyclopentadienyl)ditungsten(WϪW) (1) was lowed by a CϪC bond formation between the coordinated carried out at 253 K with the olefins ethylene (A), propene hydrocarbons. Examples for these types of reactions are (B), 1-butene (C), (E)-2-butene (D), or (Z)-2-butene (E) in the thermal oligomerisations of alkynes [2] [3] [4] at [M 2petroleum ether/THF or ether/THF. The progress of the re-(η 5 -L) 2 (CO) 4 ] complexes (M ϭ Cr, Mo; L ϭ C 5 H 5 , action is monitored by IR spectroscopy using the υCO C 9 H 7 ) [5] [6] [7] [8] , which proceed stepwise via [M 2 (η 5 -L) 2 stretching bands in the region from 2200 to 1700 cm Ϫ1 .…”

“…Examples for these types of reactions are (B), 1-butene (C), (E)-2-butene (D), or (Z)-2-butene (E) in the thermal oligomerisations of alkynes [2] [3] [4] at [M 2petroleum ether/THF or ether/THF. The progress of the re-(η 5 -L) 2 (CO) 4 ] complexes (M ϭ Cr, Mo; L ϭ C 5 H 5 , action is monitored by IR spectroscopy using the υCO C 9 H 7 ) [5] [6] [7] [8] , which proceed stepwise via [M 2 (η 5 -L) 2 stretching bands in the region from 2200 to 1700 cm Ϫ1 . Im-(CO) 4 (µ-η 2:2 -alkyne)] as intermediates [9] .…”

π-Complexes of Chromium, Molybdenum and Tungsten, Excluding those of Cyclopentadienyls and Arenes

“…However, sodium/mercury amalgam reduction of the indenyl complex [Mo(NCMe)(r| 2 -MeC=CMe) 2 (r| 5 -C9H 7 )] + results in the formation o f a C 6 bridged product analogous to (198), 564 which is also the final product in a sequence of thermally initiated alkyne linkage reactions starting f r o m [Mo 2 (CO) 4 (r| 5 -indenyl) 2 ] and MeC=CMe. 563 Some reaction chemistry o f the C 8 bridged complex (201) ( R = Me) has been developed. Protonation occurs at a terminal carbon of the C 8 chain, 566 while reaction with Ph 3 C + or excess CF 3 SO 3 H gives (202), probably via an intermediate radical monocation.…”