Chemical Bonds–Better Ways to Make Them and Break Them by Ivan Bernal (Eds.)

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2 ? 8 . 9 cis - ? 01 mmol of catalyst were used. 6 W 2 P d 2 ( C O ) 6 C p 2l-2 1 7 Pd 2 (CO)6 C p 2 l- 2 M 02 P d 2 (C O )e C p 2 L 2 1 5 2 M o2Pd2(CO)6Cp2l-2 14 6 Formula N° Catalyst precursor Presence of the Planar, Triangulated Clusters 1 4 - 1 9 a and 26 (from ref. [232]). 18. in the 51 52 All these clusters were found to be suitable catalysts for this reaction. 19). Furthermore, after photolysis, the clusters 4a, 6 3 a -c , 66, 83 and 84 could be recovered (90-98 %) by chromatography on neutral silica gel [233a].

B The selectivity is defined as [product (mmol)/MeOH reacted (mmol)] x 100. 2 mmol. 1 mmol. In the case of the cobalt-palladium cluster C o 2 P d ( D P P E ) ( C O ) 7 (7 5 ), the rate of methanol carbonylation to acetaldehyde increased compared with C o 2 ( C O ) 8 or Co4 ( C O ) 12 but the reduction of the latter to ethanol was not en han ced . On cluster 2 6 slightly increased the yield of ethanol [153, 300]. the other hand, use of the corresponding 26 , Μ = Pt 75 , Μ = Pd cobalt-platinum 47 2.

1). It thus appears that under catalytic conditions, fragmentation of the Fe3Rh cluster occurs, resulting in the formation of Rh4 ( C O ) 12 [ 10b]. The cluster [P h 4P ][F e 5 R h C ( C O ) 16] (107) was also used as catalyst precursor for the hydroformylation of 1-pentene. 7 : 1 mixture of hexanal and 2-methylpentanal, the remaining 30 % was converted into 2-pentene. Under these catalytic conditions (60 atm CO + H 2 at 100 °C), the cluster 107 was transformed and the new neutral cluster F e 4 R h 2C ( C O ) 16 (108) and the known [Ph4 P ][F e 4 R h C ( C O ) 14] (109) were isolated in 18 % and 74 % yield, respectively.