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- Tunik, Sergey, et al.
(författare)
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Reactions of Diacetylene Ligands with Trinuclear Clusters; Cyclization of Diynes with beta-amino moieties on the surface of H2Os3(CO)10
- 2001
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Ingår i: Organometallics. - : American Chemical Society (ACS). - 1520-6041 .- 0276-7333. ; 20:18, s. 3854-3863
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Tidskriftsartikel (refereegranskat)abstract
- Reactions of [H2Os3(CO)10] with the substituted diynes R-C2-C2-R' (1, R = Ph, R' = CH2NHPh; 2, R = Ph, R' = CH2NHCH2Ph; 3, R = R' = CH2NHPh) afford the clusters [HOs3(CO)10(L)] (L = {-1:2-PhCH2C(H)=C-C(H)=C-NPh} (4), {-1:2-PhCH2C(H)=C-C(H)=C-NCH2Ph} (5), and {-1:1-CH3CC=C-C(H)=C(H)-NPh} (6), which have been characterized by single-crystal X-ray diffraction analyses as well as by various spectroscopic methods. In clusters 4-6, the starting diynes 1-3 have been rearranged to form substituted pyrrolyl rings which bridge two osmium atoms in 1:2- (4, 5) or 1:1- (6) coordination modes depending on the nature of substituents in 1-3. A possible reaction pathway for the diyne cyclization reactions that yield 4-6 involves initial transfer of a hydride onto a coordinated diyne followed by a series of 1,3-shifts and subsequent nucleophilic attack of the nitrogen on the third carbon atom of the diyne system to afford the five-membered pyrrolyl ring. Cluster 6 and its previously characterized furanyl analogue [HOs3(CO)10{-1:1-(OCHCHCC)-C-CH3)}] (7) undergo facile thermal transformation accompanied by the loss of a CO ligand to give the clusters [HOs3(CO)9{3,3-CH3CC=C-C(H)=C(H)-NPh}] (8) and [HOs3(CO)9{3,3-(OCH=CHC=CCCH3)}] (9). In both 8 and 9, single-crystal X-ray analysis revealed the presence of pentagonal pyramid cluster cores containing three osmium and three carbon atoms.
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