Iridium(<scp>i</scp>) complexes bearing hemilabile coumarin-functionalised N-heterocyclic carbene ligands with application as alkyne hydrosilylation catalysts

Karataş, Mert Olgun; Alıcı, Bülent; Passarelli, Vincenzo; Özdemır, İsmaıl; Pérez‐Torrente, Jesús J.; Castarlenas, Ricardo

doi:10.1039/d1dt01946e

Cited by 11 publications

(22 citation statements)

References 78 publications

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“…The remaining two CO ligands (C2 and C3) and the nitrogen atoms of two picolyl moieties (N1 and N4) lie at the equatorial sites. The metal–carbene bond distances are 1.985(3) Å (for 1 ) and 2.003(3) Å (for 2 ), which are consistent with previous reports . The metal–carbon distances of coordinated CO ligands are similar; however, very little variation was noted.…”

Section: Resultsmentioning

confidence: 99%

Hydrosilylation of Terminal Alkynes Catalyzed by an Air-Stable Manganese–NHC Complex

et al. 2023

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In recent years, catalysis with base metal manganese has received a significant amount of interest. Catalysis with manganese complexes having N-heterocyclic carbenes (NHCs) is relatively underdeveloped in comparison to the extensively investigated manganese catalysts possessing pincer ligands (particularly phosphine-based ligands). Herein, we describe the synthesis of two imidazolium salts decorated with picolyl arms (L 1 and L 2 ) as NHC precursors. Facile coordination of L 1 and L 2 with MnBr(CO) 5 in the presence of a base resulted in the formation manganese(I)−NHC complexes (1 and 2) as an air-stable solid in good isolated yield. Single-crystal X-ray analysis revealed the structure of the cationic complexes [Mn(CO) 3 (NHC)][PF 6 ] with tridentate N,C,N binding of the NHC ligand in a facile fashion. Along with a few known manganese(I) complexes, these Mn(I)−NHC complexes 1 and 2 were tested for the hydrosilylation of terminal alkynes. Complex 1 was proved to be an effective catalyst for the hydrosilylation of terminal alkynes with good selectivity toward the less thermodynamically stable β-(Z)-vinylsilanes. This method provided good regioselectivity (anti-Markovnikov addition) and stereoselectivity (β-(Z)-product). Experimental evidence suggested that the present hydrosilylation pathway involved an organometallic mechanism with manganese(I)−silyl species as a possible reactive intermediate.

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Section: Resultsmentioning

confidence: 99%

Hydrosilylation of Terminal Alkynes Catalyzed by an Air-Stable Manganese–NHC Complex

et al. 2023

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“…Compound 2 is soluble in both polar and non-polar solvents and, in agreement with its neutral character, is non-conductor in acetone. The formation of the Rh-NHC bond was confirmed by the presence of a low-field doublet resonance at δ 182.3 ppm ( J Rh-C = 50.1 Hz) in the 13 C{ 1 H} NMR spectrum which was assigned to the C2 carbene carbon atom of the imidazole ring (NCN). 17 The vCH protons and carbons of the cod ligand showed four resonances in the spectra, which is in accordance with the axial chirality arising from restricted rotation around the Rh-NHC bond.…”

Section: Resultsmentioning

confidence: 99%

β-(Z)-Selective alkyne hydrosilylation by a N,O-functionalized NHC-based rhodium(i) catalyst

Jiménez¹,

González-Lainez²,

Passarelli³

et al. 2023

Dalton Trans.

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“…Wingtip functionalized NHCs ligands can also participate in the formation of mixed bis-NHC rhodium(I) complexes. In this context, coumarin-functionalized-NHC metal complexes display interesting catalytic and luminescence properties [ 62 , 63 , 64 , 65 , 66 ]. In particular, we have prepared coumarin-NHC derivatives of type RhCl(NHC-Cou)(η 2 ,η 2 -cod) ( 5 ) in which, in contrast to the behavior observed for related IPr- or IMes-cod compounds, the diolefin ligand can be replaced in the presence of an excess of carbene to yield bis-NHC complexes [ 53 ].…”

Section: Resultsmentioning

confidence: 99%

Preparation of Mixed Bis-N-Heterocyclic Carbene Rhodium(I) Complexes

Azpíroz

Karataş²,

Passarelli³

et al. 2022

Molecules

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A series of mixed bis-NHC rhodium(I) complexes of type RhCl(η2-olefin)(NHC)(NHC’) have been synthesized by a stepwise reaction of [Rh(μ-Cl)(η2-olefin)2]2 with two different NHCs (NHC = N-heterocyclic carbene), in which the steric hindrance of both NHC ligands and the η2-olefin is critical. Similarly, new mixed coumarin-functionalized bis-NHC rhodium complexes have been prepared by a reaction of mono NHC complexes of type RhCl(NHC-coumarin)(η2,η2-cod) with the corresponding azolium salt in the presence of an external base. Both synthetic procedures proceed selectively and allow the preparation of mixed bis-NHC rhodium complexes in good yields.

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Iridium(i) complexes bearing hemilabile coumarin-functionalised N-heterocyclic carbene ligands with application as alkyne hydrosilylation catalysts

Abstract: A set of iridium(I) complexes of formula IrCl(κC,η2-IRCouR’)(cod) or IrCl(κC, η2-BzIRCouR’)(cod) (cod = 1,5-cyclooctadiene; Cou = coumarin; I = imidazolin-2-carbene; BzI = benzimidazolin-2-carbene) have beeen prepared from the corresponding azolium...

Cited by 11 publications

References 78 publications

Hydrosilylation of Terminal Alkynes Catalyzed by an Air-Stable Manganese–NHC Complex

Hydrosilylation of Terminal Alkynes Catalyzed by an Air-Stable Manganese–NHC Complex

β-(Z)-Selective alkyne hydrosilylation by a N,O-functionalized NHC-based rhodium(i) catalyst

Preparation of Mixed Bis-N-Heterocyclic Carbene Rhodium(I) Complexes

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