Acetylenic derivatives of metal carbonyls. XIV. Cyclotrimerization of diphenylacetylene with dodecarbonyltriosmium

The photochemical and thermal reactions of a triosmium cluster carrying a γ-pyrone ligand with alkynes

“…Thus these results show that 4 is the precursor to 5 (the formation of 5, and 8, from 4 have been reported [7,18]) and 6 but not to 7, and that the formation of 7 may be activated by the c-pyrone ligand. However, we have also found that the reaction of 3a with excess PhCCPh at 110°C did not give 7, indicating that 3a is not a precursor to 7 in the thermal reaction of 1 with PhCCPh.…”

“…A second set of the same reaction under similar conditions afforded, in addition to the above, also trace amounts of 5 and the previously reported compound Os 3 (CO) 7 (PhCCPh) 3 (8) [18], both identified spectroscopically.…”

The chemistry of carbonyl clusters of transition metals containing labile and hemilabile ligands. Synthesis, reactivity, and prospects for application

“…47 It is quite obvious that diene formation in the coordination sphere of the cluster is a multistep process. The intermediate (kinetic) product of this reaction, the Os 3 (CO) 10 (µ 3 ,η 2 RC 2 R) cluster, was isolated and characterized after the two step reaction of H 2 Os 3 (CO) 10 with monoalkynes (Scheme 3).…”

Molecular rearrangements of diynes coordinated to triosmium carbonyl clusters: reactions of [Os3(μ-H)2(CO)10] and [Os3(CO)10(MeCN)2] with 1,4-dipyridylbuta-1,3-diyne

“…The chemistry of alkynes when coordinated to transition metal carbonyl clusters is well documented, [7][8][9][10][11][12][13][14][15][16] along with analogous reactions involving polyynes. Both alkynes and polyynes display a wide range of coordination modes when coordinated to polynuclear carbonyl clusters, and their reactivity is characterised by transition-metal mediated carboncarbon bond formation and cyclisations of unsaturated hydrocarbons.…”

“…Both alkynes and polyynes display a wide range of coordination modes when coordinated to polynuclear carbonyl clusters, and their reactivity is characterised by transition-metal mediated carboncarbon bond formation and cyclisations of unsaturated hydrocarbons. [11][12][13][14][15][16] Recently, the reactions of 1,3-conjugated diynes with ruthenium and osmium clusters have attracted considerable interest because of the unusual transformations that these molecules undergo when they are attached to the cluster core. For the osmium systems, observed chemistry includes intramolecular rearrangement or cyclisation of the ligand under mild conditions [17][18][19][20][21][22][23] and carbon-carbon bond rupture in thermolysis reactions, 24 and related results are observed for ruthenium cluster systems.…”