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

Abstract

Reaction of [Os 3 (m-H) 2 (CO) 10 ] with 1,4-dipyridylbuta-1,3-diyne yields two clusters, [Os 3 (m-H)(CO) 10 {m-Z 1 :in which the diyne has rearranged to form a substituted indolizine ring system. Complex 1 converts slowly to 2 at room temperature, and may be decarbonylated to yield [Os 3 (m-H)(CO) 9 {m-Z 1 :Z5, both coordinated via orthometallated pyridyl rings, and a minor product [{Os 3 (CO) 10 } 2 {m 3 -Z 1 :Z 1 :Z 1 -C 2 -(NC 5 H 4 )} 2 ] 6, coordinated via m-carbene and s-N interactions, the linking ligand retaining its central CRC bond. Complex 4 reacts with [Os 3 (m-H) 2 (CO) 10 ] to form the linked cluster [{Os 3 (m-H)(CO) 10 } 2 {m-Z7, also forming an indolizine ring system. The structures of 1-3, 6, 6 Á 2[CH 2 Cl 2 ] and 7 have been established by X-ray crystallography.

Redox-Active Heterometallic Ferrocenylalkynyl Carbosilane Dendrimers Incorporating Os3(CO)10 Clusters

“…This result agrees with our previous experiences with the reactivity of the asymmetric thioether FcCCSCCSiMe 3 in the presence of the carbonyl cluster Os 3 (CO) 10 (NCMe) 2 , in which this preference was observed . Both clusters have analogous Os−Os bond distances [Os(1)−Os(2) 2.8540(8) ( 5 ) and 2.855(1) Å ( 6 ); Os(1)−Os(3) 2.8187(8) ( 5 ) and 2.825(1) Å ( 6 ); Os(2)−Os(3) 2.7330(7) ( 5 ) and 2.725(1) Å ( 6 )] and can be compared to similar bond lengths found in [Os 3 (μ-H)(CO) 10 {μ 3 -η 1 :η 1 :η 1 -(C 5 H 4 N)CC(C 8 H 6 N)}], [{Os 3 (CO) 10 }{HCCRCCH}{Os 3 (CO) 10 }] [(R = C 4 H 4 S; R = (C 4 H 4 S) 2 ], [Os 3 (CO) 9 (μ-CO)(μ 3 -η 2 -Me 3 SiC 2 C 2 SiMe 3 )], and [Os 3 (CO) 9 (μ-CO)(FcCCSCCSiMe 3 )]…”

Coordination Behavior and Transformations of Thienyl-Substituted Diacetylenes upon Coordination to Os3H2(CO)10

“…In reactions between functionalized diynes and osmium clusters such as Os 3 H 2 (CO) 10 and Os 3 (CO) 10 (NCMe) 2 , the cluster nuclearity is maintained, but changes in the cluster core geometry and ligand rearrangements are possible . The latter phenomenon has been studied in particular in the case of hydrido clusters, where the hydride transfer from the cluster is likely to initiate ligand rearrangements.…”

“…Reactions of diynes with Os 3 H 2 (CO) 10 tend to afford cyclization of the ligand, which is thought to proceed via an abstraction of a hydrogen atom attached to the β-carbon atom of the diyne, which leads to the formation of a bond between the β-carbon atom and the third carbon of the −C2–C2– diyne group. , In the case of HOH 2 CCC–CCCH 2 OH this process leads to the formation of a cyclic product incorporating a furan ring, while the ligand PhCC–CCPh gives an indenyl fragment as the rearrangement product . The cluster [Os 3 H(CO) 10 (η 1 :η 1 -OC 4 H 2 CCH 3 )] has been shown to undergo an aldol condensation reaction with aromatic aldehydes .…”

New Method for Intramolecular Cyclization of Osmium-Coordinated Diynes Avoiding Os3(μ-H)2(CO)10 as Starting Material

“…In this way, 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, the observed chemistry includes intramolecular rearrangement or cyclization of the ligand under mild conditions and displays a wide range of coordination modes. , It is known that the activated cluster [Os 3 (CO) 10 (CH 3 CN) 2 ] typically reacts with diynes (RCCCCR, R = Me, Et, Ph, Bu t , SiMe 3 , 2-thiophenyl, ferrocenyl), at room temperature, to form the 48-electron clusters [Os 3 (μ 3 ,η 2 -RC 2 C 2 R)(μ-CO)(CO) 9 ], in which only one of the alkyne units is coordinated. , When R = Me, metallacyclic products incorporating two diynes are also obtained . Moreover, reactions with diynes (RCCCCR, R = 2-thiophenyl, ferrocenyl, Co 2 (CO) 4 (dppm)(μ 2 ,η 2 -C 2 SiMe 3 )C 4 H 2 S) involving [Os 3 (CO) 11 (CH 3 CN)] can lead to the formation of the linear 50-electron clusters [Os 3 (μ 3 ,η 1 :η 2 :η 1 -RC 2 C 2 R)(CO) 11 ], in which both alkyne units are coordinated in a parallel mode. ,, On the other hand, reactions of [Os 3 (CO) 10 (CH 3 CN) 2 ] with terminal monoalkynes, RCCH, give the triply bridging alkyne 48-electron clusters [Os 3 (μ 3 ,η 2 -alkyne)(CO) 10 ], which often lead to hydrogen transfer to the metal to give the hydrido acetylide 46-electron complexes [Os 3 H(μ 3 ,η 2 -alkyne)(CO) 9 ], where the unsaturation resulting from the loss of CO is compensated by oxidative addition, and the edge-bridged 47-electron clusters [Os 3 (μ-H){μ,η 1 :μ,η 2 -alkyne)(CO) 10 ] …”