96555-88-3Relevant academic research and scientific papers
Nickel-Mediated Trifluoromethylation of Phenol Derivatives by Aryl C?O Bond Activation
Hu, Wei-Qiang,Pan, Shen,Qing, Feng-Ling,Vicic, David A.,Xu, Xiu-Hua
, p. 16076 - 16082 (2020/07/04)
The increasing pharmaceutical importance of trifluoromethylarenes has stimulated the development of more efficient trifluoromethylation reactions. Tremendous efforts have focused on copper- and palladium-mediated/catalyzed trifluoromethylation of aryl halides. In contrast, no general method exists for the conversion of widely available inert electrophiles, such as phenol derivatives, into the corresponding trifluoromethylated arenes. Reported herein is a practical nickel-mediated trifluoromethylation of phenol derivatives with readily available trimethyl(trifluoromethyl)silane (TMSCF3). The strategy relies on PMe3-promoted oxidative addition and transmetalation, and CCl3CN-induced reductive elimination. The broad utility of this transformation has been demonstrated through the direct incorporation of trifluoromethyl into aromatic and heteroaromatic systems, including biorelevant compounds.
Halogen Photoelimination from Monomeric Nickel(III) Complexes Enabled by the Secondary Coordination Sphere
Hwang, Seung Jun,Anderson, Bryce L.,Powers, David C.,Maher, Andrew G.,Hadt, Ryan G.,Nocera, Daniel G.
, p. 4766 - 4774 (2015/10/28)
Endothermic halogen elimination reactions, in which molecular halogen photoproducts are generated in the absence of chemical traps, are rare. Inspired by the proclivity of mononuclear Ni(III) complexes to participate in challenging bond-forming reactions in organometallic chemistry, we targeted Ni(III) trihalide complexes as platforms to explore halogen photoelimination. A suite of Ni(III) trihalide complexes supported by bidentate phosphine ligands has been synthesized and characterized. Multinuclear NMR, EPR, and electronic absorption spectroscopies, as well as single-crystal X-ray diffraction, have been utilized to characterize this suite of complexes as distorted square pyramidal, S = 1/2 mononuclear Ni(III) complexes. All complexes participate in clean halogen photoelimination in solution and in the solid state. Evolved halogen has been characterized by mass spectrometry and quantified chemically. Energy storage via halogen elimination was established by solution-phase calorimetry measurements; in all cases, halogen elimination is substantially endothermic. Time-resolved photochemical experiments have revealed a relatively long-lived photointermediate, which we assign to be a Ni(II) complex in which the photoextruded chlorine radical interacts with a ligand-based aryl group. Computational studies suggest that the observed intermediate arises from a dissociative LMCT excited state. The participation of secondary coordination sphere interactions to suppress back-reactions is an attractive design element in the development of energy-storing halogen photoelimination involving first-row transition metal complexes.
Formation of nickel-thiolate aggregates via reaction with CH 2Cl2
Wang, Qiang,Marr, Andrew C.,Blake, Alexander J.,Wilson, Claire,Schroeder, Martin
, p. 2776 - 2777 (2007/10/03)
Reaction of the mononuclear nickel-thiolate complex [Ni(L 1)(dppe)] with CH2Cl2 affords the novel pentanuclear complex [Ni5Cl2(L1) 4(dppe)2], while [Ni(L1)(
New nickel-containing homogeneous hydrogenation catalysts structures of [Ni(o-MeO-dpppol)Cl2] and [Ni(dcpe)Cl2]
Angulo, Ingrid M.,Bouwman, Elisabeth,Van Gorkum, Remy,Lok, Sandra M.,Lutz, Martin,Spek, Anthony L.
, p. 97 - 106 (2008/10/08)
The didentate phosphane ligands 1,3-bis(di(ortho-methoxyphenyl)phosphanyl)-2-propanol (o-MeO-dpppol) and 1,2bis(dicyclohexylphosphanyl)ethane (dcpe) have been used in a study towards catalytic hydrogenation using homogeneous nickel catalysts. The nickel halide complexes [Ni(o-MeO-dpppol)X2] and [Ni(dcpe)X2] (X = Cl, Br or I) have been synthesized and were characterized using electronic absorption and IR spectroscopy. The structures of the complexes [Ni(o-MeO-dpppol)Cl2] and [Ni(dcpe)Cl2] have been determined by X-ray crystallography. The nickel ions in these complexes are in (distorted) square-planar geometries with NiP2Cl2 chromophores. The synthesized halide complexes and in situ mixtures of nickel acetate and the ligands were tested on catalytic activity in homogeneous hydrogenation. The ligand dcpe yields very active catalysts; turnover numbers up to 3000 in 1 h have been obtained. Generally, it appeared that the catalytic activities are higher in methanol than in methanol/dichloromethane mixtures. It was found that the catalytic activities observed for complexes containing the ligand o-MeO-dpppol are less reproducible than those of catalysts with the ligand dcpe. This lower reproducibility is probably related to the fact that the former ligand is more readily oxidized.
Preparation and reactivity of nickel(0) complexes with η2-coordinated alkynylphosphines
Bennett, Martin A.,Castro, Jeffrey,Edwards, Alison J.,Kopp, Mike R.,Wenger, Eric,Willis, Anthony C.
, p. 980 - 989 (2008/10/08)
The η2-alkynylphosphine complexes [Ni(η2-Ph2PC≡CR)(dcpe)] (R = Me (1a), CO2Me (1b), Ph (1c)), which are formed by displacement of ethylene from [Ni(C2H4)(dcpe)] by the corresponding alkynylphosphine, react with HCl (1 equiv) to give five-coordinate nickel(II) complexes, [NiCl{C(=CHR)PPh2-κP,C1}(dcpe)] (R = Me (2a), CO2Me (2b), Ph (2c)), which contain a coordinated methylenephosphanickelacyclopropane fragment. In the case of 1a, the proton adds regiospecifically at the carbon atom bearing the methyl group. This mode of addition is favored for 1b,c, but small amounts of the addition products [NiCl{η1-C(R)=CH(PPh2)}(dcpe)] (R = CO2Me (3b), Ph (3c)), arising from addition at the PPh2-bearing carbon atoms, are also formed. Unsaturated molecules such as CS2 and CO2 insert into the Ni-P bonds of complexes 2a,c to give five-membered nickelacycles. Complexes 1a, 2a,c, and 3c have been structurally characterized by X-ray diffraction analysis.
Nickel Thioether Chemistry: Synthesis, Structures and Electrochemistry of Five-co-ordinate Nickel(II) Complexes of aneS3. Crystal Structures of aneS3)(dppm)>2, aneS3)(dcpe)>2*1.25MeCN and aneS3)(tdpme)>2 aneS3 = 1,4,7-Trithiacyclononane ...>
Blake, Alexander J.,Gould, Robert O.,Halcrow, Malcolm A.,Scroeder, Martin
, p. 2909 - 2920 (2007/10/02)
Reaction of >L-L = Ph2PCH2PPh2 (dppm), R2PCH2CH2PR2 , cis-Ph2PCH=CHPPh2 (dppv), Ph2PCH2CH2CH2PPh2 (dppp) or MeC(CH2PPh2)3 (tdpme)> with 1 molar equivalent of 1,4,7-trithiacyclononane(aneS3) afforded the complex cations aneS3)(L-L)>(2+).The crystal structures of aneS3)(dppm)>2, aneS3)(dcpe)>2*1.25MeCN and aneS3)(tdpme)>2 showed five-co-ordinate complexes with distorted square-pyramidal geometries about the nickel(II) centres with S-donors of aneS3 occupying two basal and the apical position, Ni-Sapical 2.40-2.65 Angstroem, Ni-Sbasal 2.22-2.27 Angstroem, Ni-Pbasal 2.17-2.22 Angstroem.The complex aneS3)(dppm)>2 crystallises in triclinic space group P, a = 10.9748(25), b = 13.9702(20), c = 15.7688(24) Angstroem, α = 80.071(7), β = 70.817(8), γ = 76.441(8) deg, Dc = 1.374 g cm-3, Z = 2; aneS3)(dcpe)>2*1.25MeCN crystallises in triclinic space group P, a = 12.432(8), b = 13.382(4), c = 15.070(6) Angstroem, α = 86.83(2), β = 70.47(2), γ = 77.28(2) deg, Dc = 1.445 g cm-3, Z = 2; aneS3)(tdpme)>2 crystallises in monoclinic space group Cc, a = 10.7597(16), b = 37.399(5), c = 13.104(3) Angstroem, β = 103.746(11) deg, Dc = 1.491 g cm-3, Z = 4.Cyclic voltammetry of the complexes aneS3)(L-L)>2 in MeCN (0.1 mol dm-3 NBu4PF6) at 293 K at platinum electrodes showed one chemically reversible and one quasi-reversible one-electron reduction at 1E1/2 = -0.77 to -1.16 V, ΔEp = 61-92 mV, 2E1/2 = -1.31 to -1.93 V vs. ferrocene-ferrocenium.On the basis of ESR and electronic spectroscopy, these reduction products are asiigned as pyramidal d9 nickel(I) aneS3)(L-L)>(1+) with binding of both P-donors retained, and tetrahedral 210 nickel(0) aneS3)(L-L)>(0) species respectively.The reaction of aneS3)(L-L)(1+) with CO in MeCN is discussed.
Synthesis and single-crystal X-ray study of the mononuclear η2-benzyne (dehydrobenzene) nickel(0) complex Ni(η2-C6H4)((C6H 11)2PCH2CH2P(C6H 11)2). Insertion reactions with simple molecules and X-ray crystal structure of the ...
Bennett, Martin A.,Hambley, Trevor W.,Roberts, Nicholas K.,Robertson, Glen B.
, p. 1992 - 2000 (2008/10/08)
Full title: Synthesis and single-crystal X-ray study of the mononuclear η2-benzyne (dehydrobenzene) nickel(0) complex Ni(η2-C6H4)((C6H 11)2PCH2CH2P(C6H 11)2). Insertion reactions with simple molecules and X-ray crystal structure of the nickelaindan complex Ni(CH2CH2C6H4-o)((C 6H11)2PCH2CH2P(C 6H11)2). Sodium amalgam reduction of NiCl(C6H4Br-2)(Cy2PCH2CH 2PCy2)·0.5THF (6) (Cy = cyclohexyl, C6H11) gives a mononuclear nickel(0) complex, Ni(η2-C6H4)(Cy2PCH 2CH2PCy2) (3), which has been characterized by microanalysis, by mass, infrared, and NMR (1H, 13C, 31P) spectroscopy, and by single-crystal X-ray structural analysis. Crystals of 3 are orthorhombic, space group Pbca, with a = 16.068 (1) A?, b = 17.189 (1) A?, c = 22.358 (1) A?, and Z = 8. The structure was solved by heavy-atom methods and refined by least-squares methods to R = 0.035 and Rw = 0.055 for 4203 independent reflections. The molecule consists of a central nickel atom coordinated by a symmetric η2-benzyne ligand [Ni-C(1) = 1.870 (4) A?, Ni-C(2) = 1.868 (4) A?], the coordination geometry being close to trigonal planar. The coordinated C-C bond length of 1.332 (6) A? is significantly larger than those observed in alkyne complexes of zerovalent nickel and platinum. The remaining C-C bonds of the six-membered ring are almost equal in length (average 1.385 A?), consistent with a delocalized aromatic structure for the benzyne ligand. Complex 3 reacts with iodine and methyl iodide at room temperature to give, respectively, the 2-iodophenyl and o-tolyl complexes NiI(C6H4Y-2)(Cy2PCH2CH 2PCy2) (Y = I (7), Me (8)). Carbon dioxide, ethylene, and dimethyl acetylenedicarboxylate insert into the nickel-benzyne bond of 3 to give the nickelacycles Ni(C6H4COO)(Cy2PCH2CH 2PCy2) (10), Ni(CH2CH2C6H4-o)(Cy 2PCH2CH2PCy2) (11), and Ni(C(CO2Me)=C(CO2Me)C6H4-o)(Cy 2PCH2CH2PCy2) (12), respectively, whereas diphenylacetylene displaces benzyne to give Ni(PhC≡CPh)(Cy2PCH2CH2PCy2) (13). Crystals of 11 are monoclinic, space group P21/n, with a = 15.792 (6) A?, b = 17.471 (6) A?, c = 12.104 (4) A?, β = 104.09 (2)°, and Z = 4. The structure was solved and refined as for 3 to R = 0.070 and Rw = 0.071 for 2379 independent reflections. The nickel atom is coordinated in an approximately planar arrangement by the bidentate di(tertiary phosphine) and by two carbon atoms of a five-membered, half-chair-shaped chelate ring, the Ni-C(aryl) and Ni-C(alkyl) bond lengths being 1.951 (12) and 1.988 (12) A?, respectively.
