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Open Access item Different coordination modes of an aryl-substituted hydrotris(pyrazolyl)borate ligand in rhodium and iridium complexes

Authors:Conejero Iglesias, Salvador
Esqueda Oliva, Ana Cristina
Villar Valpuesta, José E.
Álvarez, Eleuterio
Maya, Celia
Carmona Guzmán, Ernesto
Keywords:Rhodium, Iridium, Tris(pyrazoly)borate, C-H activation
Issue Date:21-Dec-2010
Citation:Inorganica Chimica Acta 369(1): 165-172 (2011)
Abstract:Complexes TptolRh(C2H4)2 (1a) and TptolRh(CH2C(Me)C(Me)CH2) (1b) have been prepared by reaction of KTptol with the appropriate [RhCl(olefin)2]2 dimer (Tptol means hydrotris(3-p-tolylpyrazol-1-yl)borate). The two complexes show a dynamic behaviour that involves exchange between κ2 and κ3 coordination modes of the Tptol ligand. The iridium analogue, TptolIr(CH2C(Me)CHCH2) (2) has also been synthesized, and has been converted into the Ir(III) dinitrogen complex [(κ4-N,N’,N’’,C-Tptol)Ir(Ph)(N2) (3) by irradiation with UV light under a dinitrogen atmosphere. Compound 3 constitutes a rare example of Ir(III)–N2 complex structurally characterized by X-ray crystallography. Its N2 ligand can be easily substituted by acetonitrile or ethylene upon heating and denticity changes in the Tptol ligand, from κ4-N,N’,N’’,C (monometallated Tptol, from now on represented as Tptol′) to κ5-N,N′,N″,C,C″ (dimetallated Tptol ligand, represented as Tptol″) have been observed. When complex 3 is heated in the presence of acetylene, dimerization of the alkyne takes place to yield the enyne complex [(κ5-N,N′,N′′,C,C′-Tptol)Ir(CH2CHCCH), 7¸ in which the unsaturated organic moiety is bonded to iridium through the carbon–carbon double bond.
Description:23 páginas, 5 figuras, 6 esquemas.
Publisher version (URL):http://dx.doi.org/10.1016/j.ica.2010.12.031
Appears in Collections:(IIQ) Artículos

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