12125-72-3Relevant articles and documents
Heterobimetallic indenyl complexes. Kinetics and mechanism of substitution and exchange reactions of trans-[Cr(CO)3-indenyl-Rh(CO)2] with olefins
Bonifaci, Chiara,Carta, Giovanni,Ceccon, Alberto,Gambaro, Alessandro,Santi, Saverio,Venzo, Alfonso
, p. 1630 - 1636 (1996)
The trans coordination of the benzene ring of the indenyl-Rh(CO)2 complex with tricarbonylchromium strongly enhances the rate of substitution of CO's with bidentate olefins, 1,5-cyclooctadiene (COD) and norbornadiene (NBD) ( extra-indenyl effect ). The activation parameters suggest an associative reaction pathway assumed to proceed via the intermediacy of a nonisolable low-hapticity species, η1-indenyl-Rh(CO)2(L2). In addition, the rate of exchange of the Cr(CO)3 group of the complexes trans-[Cr(CO)3-indenyl-Rh(CO)2], 3, and trans-[Cr(CO)3-indenyl-Rh(COD)], 3a, and suitable acceptors (hexamethylbenzene and cycloheptatriene) is markedly increased with respect to that measured for the same reaction in the monometallic complex η-naphthalene-Cr(CO)3 ( extra-naphthalene effect ). These mutual effects of the Cr(CO)3 and RhL2 units are transmitted through the 10 π electron indenyl framework, and the results obtained are in agreement with the existence of an haptomeric ground-state equilibrium between the two isomers trans-[Cr(CO)3μ,η6:η 3-indenyl-RhL2], I, and trans-[Cr(CO)3-μ,η4:η 5-indenyl-RhL2], II.
Munro, J. D.,Pauson, P. L.
, (1961)
7?-acetoxy-(1H?, 6H?)-bicyclo[4.4.1]undeca-2,4,8-triene via chromium-mediated higher order cycloaddition: [ bicyclo[4.4.1]undeca-3,7,9-triene-2-ol, acetate, endo- (±)- ]
Rigby, James H.,Fales, Kevin R.,Lee Trout, Robert E.,Smith, Amos B.
, p. 121 - 121 (2017/09/28)
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Substitution and addition reactions of the (CO)3(η7-tropylium)M cations (M = Cr, Mo, W) with tertiary diphosphines
Brown, David A.,Burns, John,Glass, William K.,Cunningham, Desmond,Higgins, Tim,McArdle, Patrick,Salama, Mabrouk M.
, p. 2662 - 2667 (2008/10/08)
The reactions of the title compounds I-III, [(η7-C7H7)M(CO)3]BF4 (M = Cr, Mo, and W, respectively), with the diphosphines PPh2(CH2)nPPh2 (n = 1-4) at low temperatures (-40 to -60°C) form two new series of complexes which are quite different from previous carbonyl substitution products. The first series (IV-VI) formed by the diphosphines (n = 1-3) comprise 7-exo ring adducts involving the bonding of only one phosphorus atom of the diphosphine to ring carbon atom 7 of I. The second series (VII and VIII) are diphosphine ring linked dimers, e.g. [(7,7′-exo-dppb){η6-C7H7)Cr(CO) 3}2] [BF4]2, for which X-ray crystallography confirms a diphosphine linked ring-ring structure with the Cr(CO)3 moieties situated on opposite sides of the ring systems. The ring C-phosphorus bond length of 1.852 A? indicates a relatively weak bond, consistent with facile cleavage of these adducts on reaction with nucleophiles such as hydride.
