858345-70-7Relevant academic research and scientific papers
Synthesis, structure, and solution dynamics of pentamethylcyclopentadienyl nickel complexes bearing N-heterocyclic carbene ligands
Ritleng, Vincent,Barth, Caroline,Brenner, Eric,Milosevic, Sandra,Chetcuti, Michael J.
, p. 4223 - 4228 (2008)
Neutral pentamethylcyclopentadienyl nickel complexes of general formula [Ni(NHC)X(η5-C5Me5)] [NHC = 1,3-dimethylimidazol-2-ylidene (Me-NHC), 1,3-bis(2,4,6,-trimethylphenyl) imidazol-2-ylidene (Mes-NHC), 1,3-bis(2,6-diisopr
Simple synthesis of CpNi(NHC)Cl complexes (Cp = cyclopentadienyl; NHC = N-heterocyclic carbene)
Kelly III, Roy A.,Scott, Natalie M.,Diez-Gonzalez, Silvia,Stevens, Edwin D.,Nolan, Steven P.
, p. 3442 - 3447 (2005)
The reaction of saturated and unsaturated imidazolium salts with nickelocene in refluxing THF results in the formation of NHC complexes of general formula CpNi(NHC)Cl (NHC = SIMes (2), IPr (3), SIPr (4)). This protonation of Cp2Ni was also test
Nickel(I) monomers and dimers with cyclopentadienyl and indenyl ligands
Wu, Jianguo,Nova, Ainara,Balcells, David,Brudvig, Gary W.,Dai, Wei,Guard, Louise M.,Hazari, Nilay,Lin, Po-Heng,Pokhrel, Ravi,Takase, Michael K.
, p. 5327 - 5337 (2014)
The reaction of (μ-Cl)2Ni2(NHC)2 (NHC=1,3-bis(2,6-diisopropylphenyl)-1,3-dihydro-2H-imidazol-2-ylidene (IPr) or 1,3-bis(2,6-diisopropylphenyl)imidazolidin-2-ylidene (SIPr)) with either one equivalent of sodium cyclopentadienyl (NaCp) or lithium indenyl (LiInd) results in the formation of diamagnetic NHC supported NiI dimers of the form (μ-Cp)(μ-Cl)Ni2(NHC)2 (NHC=IPr (1 a) or SIPr (1 b); Cp=C5H5) or (μ-Ind)(μ-Cl)Ni2(NHC) 2 (NHC=IPr (2 a) or SIPr (2 b); Ind=C7H9), which contain bridging Cp and indenyl ligands. The corresponding reaction between two equivalents of NaCp or LiInd and (μ-Cl)2Ni 2(NHC)2 (NHC=IPr or SIPr) generates unusual 17 valence electron NiI monomers of the form (η5-Cp)Ni(NHC) (NHC=IPr (3 a) or SIPr (3 b)) or (η5-Ind)Ni(NHC) (NHC=IPr (4 a) or SIPr (4 b)), which have nonlinear geometries. A combination of DFT calculations and NBO analysis suggests that the NiI monomers are more strongly stabilized by the Cp ligand than by the indenyl ligand, which is consistent with experimental results. These calculations also show that the monomers have a lone unpaired-single-electron in their valence shell, which is the reason for the nonlinear structures. At room temperature the Cp bridged dimer (μ-Cp)(μ-Cl)Ni2(NHC)2 undergoes homolytic cleavage of the Ni-Ni bond and is in equilibrium with (η5-Cp) Ni(NHC) and (μ-Cl)2Ni2(NHC)2. There is no evidence that this equilibrium occurs for (μ-Ind)(μ-Cl)Ni 2(NHC)2. DFT calculations suggest that a thermally accessible triplet state facilitates the homolytic dissociation of the Cp bridged dimers, whereas for bridging indenyl species this excited triplet state is significantly higher in energy. In stoichiometric reactions, the Ni I monomers (η5-Cp)Ni(NHC) or (η5-Ind) Ni(NHC) undergo both oxidative and reductive processes with mild reagents. Furthermore, they are rare examples of active NiI precatalysts for the Suzuki-Miyaura reaction. Complexes 1 a, 2 b, 3 a, 4 a and 4 b have been characterized by X-ray crystallography. On the nickel: The syntheses, reactivity and electronic structures of NiI monomers with terminal cyclopentadienyl (Cp) and indenyl (Ind) ligands and NiI dimers with bridging Cp and indenyl ligands are reported. NiI dimers with bridging Cp ligands undergo facile homolytic cleavage of the Ni-Ni bond and are in equilibrium with two other NiI complexes. Several of the Ni I complexes described are active precatalysts for the Suzuki-Miyaura reaction (see scheme, NHC=N-heterocyclic carbene).
Complexes LNi(Cp)X with alkylamino-substituted N-heterocyclic carbene ligands (L) and their catalytic activity in the Suzuki—Miyaura reaction
Chernyshev, V. M.,Chesnokov, V. V.,Shevchenko, M. A.,Soliev, S. B.,Tafeenko, V. A.
, p. 1281 - 1289 (2021/08/10)
New nickel(ii) complexes of the general formula LNi(Cp)X (L is an N-heterocyclic carbene (NHC) ligand of the 1,2,4-triazole or imidazole series; Cp is the cyclopentadienyl anion; X = Cl, I) are reported. In these complexes, the NHC ligands (L) contain an alkylamino group at the 3 or 4 position of the heterocycle. The synthesized complexes and structurally similar complexes without an alkylamino group were tested for catalytic activity in the Suzuki—Miyaura reaction. The introduction of an alkylamino group into the NHC ligand leads to the enhancement of the catalytic activity of complexes with N,N′-diaryl-substituted NHC ligands of the imidazole series and a decrease in the activity of the complexes with N,N′-dialkyl-substituted NHC ligands of the 1,2,4-triazole series.
Microwave-assisted synthesis of (N-heterocyclic carbene)Ni(Cp)Cl complexes
Landers, Brant,Navarro, Oscar
, p. 350 - 353 (2012/03/13)
The use of microwave heating for the synthesis of a series of (N-heterocyclic carbene)Ni(Cp)Cl complexes is presented. This protocol allows for a considerable reduction of the reaction times required using conventional heating, while affording comparable
