Nucleophilic attack at co-ordinated isocyanides promoted by the 2-pyridyl ligand

Crociani, B.; Bianca, F. Di; Fontana, Alberta; Forsellini, E.; Bombieri, G.

doi:10.1039/dt9940000407

Cited by 27 publications

(20 citation statements)

References 14 publications

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“…95,96 Comparison of the Pt-C bond distances in 100, its protonated form 130a, and 130b is not conclusive for establishing metal-carbon π-interactions (see Table 3). 94 Interestingly, the heterocycles in the carbenoid complexes 130 are oriented almost perpendicular to the metal coordination plane, while in the pyridyl complex 129, the ligand is tilted only by ∼10°.…”

Section: Nitrogen Functionalization Of Metallated Pyridyl Ligandsmentioning

confidence: 99%

“…In the early 1980s, the groups of Isobe 88,89 and Crociani [90][91][92][93][94][95] successfully prepared nickel, palladium, and platinum py- These early studies focused on the effect of the metal fragment on the reactivity of the pyridine, rather than on the carbene-type bonding of the ligand. Titration experiments showed that the Brønsted basicity of pyridine in the palladium complex 123a is ∼4 orders of magnitude higher than that of unsubstituted pyridine.…”

Section: Nitrogen Functionalization Of Metallated Pyridyl Ligandsmentioning

confidence: 99%

“…90 The high basicity of 2-metallated pyridines has been further illustrated by the successful activation of CH 2 Cl 2 by complex 129 to form the N-alkylated chloride salt 130b (see Scheme 43). 94 Replacing the trans-coordinated phosphine spectator ligands by bidentate cis-chelating ligands such as1,2-bis(diphenylphosphino)ethane (dppe) or dimethyldithiocarbamate (dmtc) does not influence this reactivity pattern. 93,[95][96][97] Because the 2-and 4-metallated congeners differ considerably in their reactivity, the contribution of a zwitterionic pyridinylium-type resonance structure (130′; see Scheme 43) has been suggested to be more relevant than the neutral pyridylidene structure 130′′.…”

Section: Nitrogen Functionalization Of Metallated Pyridyl Ligandsmentioning

confidence: 99%

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Beyond ConventionalN-Heterocyclic Carbenes: Abnormal, Remote, and Other Classes of NHC Ligands with Reduced Heteroatom Stabilization

et al. 2009

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theme are found via the replacement or displacement of one N atom, thus providing carbenes derived from pyrazolium, isothiazolium, and even quinolinium salts that contain a stabilizing heteroatom in a remote position (G-J in Figure 1). Recently, carbenes such as K, which are comprised of only one heteroatom and lack delocalization through the heterocycle, have been discovered as versatile ligands, thus constituting another important class of carbenes with low heteroatom stabilization. Both the synthesis of the organometallic complexes of these ligands as well as the (catalytic) properties of the coordinated metal centers generally show distinct differences, compared to the more classical NHC complexes, such as C2-metallated imidazolylidenes. This review intends to describe such differences and highlights the chemical peculiarities of these types of N-heterocyclic carbene complexes. It introduces, in a qualitative manner, the synthetic routes that have been established for the preparation of such complexes, covering the literature from the very beginning of activities in this area up to 2008. While specialized reviews on some aspects of the present topic have recently appeared, 7 a comprehensive overview of the subject has not been available thus far. Rather than just being descriptive, the present account is mainly directed toward the impact of these still unusual metal-carbene bonding modes on the electronic properties and on the new catalytic applications that have been realized by employing such new carbene complexes. As a consequence of our focus on complexes with less-stabilized heterocyclic ligands, systems comprising acyclic carbenes have not been included, and the interested reader is, instead, referred to the pioneering and

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Section: Nitrogen Functionalization Of Metallated Pyridyl Ligandsmentioning

confidence: 99%

Section: Nitrogen Functionalization Of Metallated Pyridyl Ligandsmentioning

confidence: 99%

Section: Nitrogen Functionalization Of Metallated Pyridyl Ligandsmentioning

confidence: 99%

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Beyond ConventionalN-Heterocyclic Carbenes: Abnormal, Remote, and Other Classes of NHC Ligands with Reduced Heteroatom Stabilization

et al. 2009

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“…24 This result also provides an explanation for the increased basicity of the nitrogen in pyridyl metal complexes which can even lead to the activation of dichloromethane. [50][51][52][53][54][55] …”

Section: Figurementioning

confidence: 99%

Pyridine-Derived N-Heterocyclic Carbenes: An Experimental and Theoretical Evaluation of the Bonding in and Reactivity of Selected Normal and Abnormal Complexes of Nickel(II) and Palladium(II)

et al. 2010

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“…Hydrolysis of transition-metal isocyanide complex, [Pt{η 1 (C 2 )-C 5 H 4 N}(CNR)(dppe)] + (R = 4-methoxyphenyl, dppe: 1,2-bis(diphenylphosphino)ethane), has been reported. 15 Coordination of the isocyanide with the cationic [CCH] subunit enhanced nucleophilic attack by water to give 10 at room temperature.…”

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confidence: 99%

Activation of Isocyanides and Hydrosilanes by a Cationic [CCH] Subunit in a Tetrairon–Tetracarbon Cluster

Taniwaki

Ohta

Okazaki

2015

Bulletin of the Chemical Society of Japan

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The reactivity of [(η5-C5H4Me)4Fe4(HCCH)(HCC-NC4H4N)](PF6)2 (1) toward isocyanides and hydrosilanes was examined. The reaction of 1 with tert-butyl isocyanide led to C(sp3)-N(sp) bond cleavage to give [(η5-C5H4Me)4Fe4(HCCH)(HCC-CN)](PF6) (2), 1-tert-butylpyrazinium salt, and isobutene. In the reactions with cyclohexyl and benzyl isocyanides, isocyanide adducts [(η5-C5H4Me)4Fe4(HCCH)(HCC-CNR)](PF6)2 (R = Cy (5), CH2Ph (6)) were obtained and further transformed to 2 (70 °C, 10 h for 5; RT, 120 h for 6). The reactions of 1 with aryl isocyanides such as 2,6-dimethylphenyl and 2,4,6-tri-tert-butylphenyl isocyanides yielded thermally stable [(η5-C5H4Me)4Fe4(HCCH)(HCC-CNAr)](PF6)2 (Ar = 2,6-Me2C6H3 (8), 2,4,6-tBu3C6H2 (9)). The Si–H bonds of R3SiH (R = Et, Ph), Ph2SiH2, and PhSiH3 were activated to give [(η5-C5H4Me)4Fe4(HCCH)2](PF6) together with the corresponding fluorosilanes. Coordination of the substrates with a cationic [CCH] subunit promoted the cleavage of the carbon–nitrogen and silicon–hydrogen bonds to give the products.

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Nucleophilic attack at co-ordinated isocyanides promoted by the 2-pyridyl ligand

Cited by 27 publications

References 14 publications

Beyond ConventionalN-Heterocyclic Carbenes: Abnormal, Remote, and Other Classes of NHC Ligands with Reduced Heteroatom Stabilization

Beyond ConventionalN-Heterocyclic Carbenes: Abnormal, Remote, and Other Classes of NHC Ligands with Reduced Heteroatom Stabilization

Pyridine-Derived N-Heterocyclic Carbenes: An Experimental and Theoretical Evaluation of the Bonding in and Reactivity of Selected Normal and Abnormal Complexes of Nickel(II) and Palladium(II)

Activation of Isocyanides and Hydrosilanes by a Cationic [CCH] Subunit in a Tetrairon–Tetracarbon Cluster

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