1410026-33-3Relevant academic research and scientific papers
Azaferrocene-Based PNP-Type Pincer Ligand: Synthesis of Molybdenum, Chromium, and Iron Complexes and Reactivity toward Nitrogen Fixation
Kuriyama, Shogo,Arashiba, Kazuya,Nakajima, Kazunari,Tanaka, Hiromasa,Yoshizawa, Kazunari,Nishibayashi, Yoshiaki
, p. 4856 - 4861 (2016)
A series of azaferrocene-based PNP-type pincer ligands were designed and prepared as new PNP-type pincer ligands. Some transition-metal complexes, including molybdenum, chromium, and iron complexes, bearing these azaferrocene-based PNP-type pincer ligands were also prepared and characterized by X-ray analysis. The stoichiometric and catalytic reactivities of molybdenum–dinitrogen complexes toward nitrogen fixation were investigated in detail.
Asymmetric bis-PNP pincer complexes of zirconium and hafnium-a measure of hemilability
Idelson, Celia,Webster, Leah,Kr?mer, Tobias,Chadwick, F. Mark
, p. 16653 - 16656 (2020)
Asymmetrically-bound pyrrolide-based bis-PNP pincer complexes of zirconium and hafnium have been formed. The [κ2-PNPPh][κ3-PNPPh]MCl2 species are in direct contrast to previous zirconium PNP pincer complexes. The pincer ligands are fluxional in their binding and the energy barrier for exchange has been approximated using VT-NMR spectroscopy and the result validated by DFT calculations.
Synthesis, characterization, and catalytic activity of nickel(II) alkyl complexes supported by pyrrole-diphosphine ligands
Venkanna, Gopaladasu T.,Tammineni, Swetha,Arman, Hadi D.,Tonzetich, Zachary J.
, p. 4656 - 4663 (2013/09/23)
The organometallic Ni(II) chemistry of the pyrrole-based pincer ligands (P2RPyr)- (P2RPyr = 2,5-(R2PCH2)2C4H2N, R = Ph, Cy) is reported. Reactions of Grignard reagents with [NiCl(P 2RPyr)] afford a variety of alkyl and aryl complexes (methyl, ethyl, benzyl, phenyl, and allyl) that all display square-planar geometries about nickel. The hydride complex [NiH(P2 CyPyr)] can also prepared either through treatment of [NiCl(P 2CyPyr)] with LiHBEt3 or by reaction of H(P2RPyr) with [Ni(COD)2] (COD = 1,4-cyclooctadiene). Reactions of the methyl and hydride complexes with CO and CO2, respectively, evince clean migratory insertion chemistry of the Ni-C and Ni-H bonds. Both the alkyl and chloride complexes are active catalysts for the Kumada coupling of aryl chlorides and aryl or alkyl Grignard reagents at room temperature. The solid-state structures of several of the complexes are reported.
Nickel(II) complexes containing a pyrrole-diphosphine pincer ligand
Venkanna, Gopaladasu T.,Ramos, Teresa Virginia M.,Arman, Hadi D.,Tonzetich, Zachary J.
, p. 12789 - 12795 (2013/02/22)
A new pincer ligand, (P2PhPyr)-, based on the anion of 2,5-bis[(diphenylphosphino)methyl]pyrrole has been prepared in four steps from pyrrole. The ligand undergoes oxidation to diphosphine oxide under ambient conditions and was therefore isolated as its borane adduct, H(P 2PhPyr)·2BH3 (2). Delivery of the ligand to nickel(II) was accomplished by the direct reaction of NiCl2 with 2 in the presence of Et2NH to afford [NiCl(P2 PhPyr)]. Salt metathesis reactions of the chloro complex afford new compounds including [Ni(CH3)(P2PhPyr)] and [Ni(NCCH3)(P2PhPyr)](OTf). In all cases, the ligand gives rise to diamagnetic square-planar complexes, which have been fully characterized in solution and the solid state. All complexes examined display an irreversible oxidation to nickel(III) according to cyclic voltammetry. Reduction of the chloro complex in dichloromethane results in an electrocatalytic process, whereas reduction in tetrahydrofuran leads to the irreversible formation of a nickel(I) species.
Pyrrole-based new diphosphines: Pd and Ni complexes bearing the pnp pincer ligand
Kumar, Shanish,Mani, Ganesan,Mondal, Sukanta,Chattaraj, Pratim Kumar
, p. 12527 - 12539 (2013/01/15)
A new class of diphosphine PNP pincer ligand, 2,5- bis(diphenylphosphinomethyl)pyrrole 2, was synthesized by the reaction between Ph2PH and 2,5-bis(dimethylaminomethyl)pyrrole in 90% yield. The analogous reaction of Ph2PH with 1,9-bis(dimethylaminomethyl) diphenyldipyrrolylmethane readily afforded a PNNP type diphosphine ligand, 1,9-bis(diphenylphosphinomethyl)diphenyldipyrrolylmethane 5 in 92% yield. These phosphine compounds were oxidized with H2O2 and S 8 to give the corresponding phosphoryl and thiophosphoryl compounds 6-9 in very good yields. The reaction of the PNP pincer ligand 2 with [PdCl 2(PhCN)2] in the presence of Et3N afforded the mononuclear Pd(II) complex, [PdCl{C4H2N-2,5-(CH 2PPh2)2-κ3PNP}] 10 in 87% yield. Conversely, treatment of 2 with [PdCl2(PhCN)2] in the absence of Et3N gave the dinuclear Pd(II) complex [Pd 2Cl4{μ-C4H3N-2,5-(CH 2PPh2)2-κ2PP}2], the structure which is proposed based on the spectroscopic data. When 2 was treated with Pd(0) precursor [Pd2(dba)3]·CHCl 3 the dinuclear Pd(I) complex [Pd2{μ-C 4H2N-2,5-(CH2PPh2) 2-κ2PN,κ1P}2], 12, was obtained in 23% yield. The formation of complex 12 is solvent dependent, which transforms into complex 10 in CDCl3 as studied by variable temperature 1H and 31P NMR methods. Treatment of 2 with [Ni(OAc)2]·4H2O gave the mononuclear Ni(II) pincer complex [Ni(OAc){C4H2N-2,5-(CH2PPh 2)2-κ3PNP}], 13, which upon treatment with an excess of LiCl or LiBr or KI afforded the respective halide ion substituted Ni(II) complexes, [NiX{C4H2N-2,5-(CH 2PPh2)2-κ3PNP}] (X = Cl, Br, and I), 14-16, in very good yields. The structures of 5, 2,5- bis(diphenylphosphorylmethyl)pyrrole 6, 10, 12, and 14-16 were determined by the single crystal X-ray diffraction method. In the structure of 12, two short contacts between the diagonally positioned Pd and P atoms are observed. To understand these weak interactions, density functional theory (DFT) calculations were done and an interaction MO diagram is presented.
