Mechanisms of substitution of ligand-bridged diiron hexacarbonyl complexes. .mu.-Butatriene-bis(tricarbonyliron) complexes: crystallographic determination of the structure of a carbonyl substitution product and evidence for a carbonyl-inserted intermediate

Effect of marine collagen peptides on long bone development in growing rats

“…Die Struktur von 6 23 ist als μ‐ trans ‐Butatrien‐Komplex in Analogie zu den μ‐ trans ‐Butadiin‐Komplexen10 als Dititanabicyclus und nicht als σ‐Propargyl‐ oder π‐Allenylkomplex19 zu beschreiben. Sie unterscheidet sich auch von “verbrückten allylischen” Strukturen24a,b und μ‐Butin‐1,4‐diyl‐24b oder speziellen μ‐Butadiin‐Komplexen 24c…”

Stable Cyclopentynes—Made by Metals!?

“…In analogy to μ‐ trans ‐butadiyne complexes10 the structure of 6 23 as a μ‐ trans ‐butatriene complex is better described as a dititanabicycle and not a σ‐propargyl or π‐allenyl complex 19. It is also different from “bridged allylic”24a,b and μ‐butyne‐1,4‐diyl24b structures and from special μ‐butadiyne complexes 24c…”

Alkynyl-Dicobalt Hexacarbonyl Complexes of Menthyl Cations: Isolobal Substitution of [Co(CO)3]+by Fe(CO)3as a Structural Model

“…As noted above, the reaction of (propargyl alcohol)Co 2 (CO) 6 clusters with Fe(CO) 5 in refluxing acetone to yield iron−cobalt clusters was originally reported by Aime and Osella in 1983 and was described as a “dehydroxylation process”; since that time, a number of other examples of this metal exchange process have been reported. − However, the reactions of Fe(CO) 5 with (alkynylcyclopentadienol)Co 2 (CO) 6 complexes yielded unexpected products, 18 , in which an (η 5 -cyclopentadienyl)Fe(CO) 2 moiety was linked to a tricarbonylcobalt cluster vertex via a bridging hydride . As depicted in Scheme , it was proposed that initial attack by the hydroxyl oxygen on an iron carbonyl, migration of hydrogen to form a metal hydride, and loss of two iron carbonyls allowed complexation to the cyclopentadiene ring .…”

“…The reaction of (propargyl alcohol)Co 2 (CO) 6 clusters, or their corresponding diols (HOCR 2 CCCR 2 OH)Co 2 (CO) 6 , with Fe(CO) 5 in refluxing acetone to yield iron−cobalt or di-iron clusters, respectively, was originally reported by Aime and Osella in 1983 and was described as a “dehydroxylation process” (Scheme ) . Since that time, a number of other examples of this metal exchange process have been reported. − These mixed-metal clusters provide excellent structural models of the isoelectronic [(R′CC-CR 2 )Co 2 (CO) 6 ] + cations, whereby a neutral Fe(CO) 3 moiety functions as an isolobal replacement for the cationic [Co(CO) 3 ] + unit . To this end, the (phenylethynylmenthol)Co 2 (CO) 6 clusters 8 and 9 were each treated with Fe(CO) 5 in refluxing acetone and the products separated by chromatography on a silica column.…”

“…Several relevant X-ray crystal structures containing (OC) 3 Fe···CR 2 moieties have been reported. In Cp 2 W 2 (CO) 4 Fe(CO) 3 (CCH 2 ), (MeCCCH 2 )Fe(CO) 3 Co(CO) 2 PPh 3 , and (CH 2 CC=CH 2 )Fe 2 (CO) 5 PPh 3 , the iron−carbon distances are 2.21, 2.195, and 2.208 Å, respectively. Taking an extreme view, these relatively short bonds can be considered as arising from the interaction of CH 2 + (i.e., primary) cations with [Fe(CO) 3 ] − vertices.…”