14076-99-4Relevant academic research and scientific papers
The effect of pressure on the Raman spectra of solids. VII. The internal Raman bands in solid and coordinated pyridine
Heyns, A.M.,Venter, M.W.
, p. 7581 - 7591 (1990)
The pressure dependences of the internal Raman-active modes of solid pyridine and pyridine-d5 in both the crystalline and glassy modifications as well as of the complexes Zn(py)2Cl2, Ni(py)2Cl2, and Ni(py)4Cl2 are reported.When pyridine is frozen by the application of pressure, some ring modes as well as those involving the hydrogen atoms reflect this transformation.Upon the coordination of pyridine to metal ions, the ring vibrations show appreciable blue shifts.The pressure dependences of ν1, the C-C stretching mode, and ν12, the in-plane ring bending mode of the pyridine rings, are discussed in detail.The unusually high d5-h5 isotopic ratio of ν12 and its contrasting pressure dependences in the liquid and condensed phases of pyridine-d5 are explained.The association of pyridine molecules in the condensed phase does not occur through hydrogen bonds and the C-H stretching modes, in particular, show that repulsive intermolecular forces become very significant at higher pressures.The ratio of the intensities Ιν12/Ιν1 varies linearly with the strength of the M-N bonds in a series of pyridine complexes and a correlation also exists between Ιν12/Ιν1 and δν12/δp.The vibrations ν1 and ν2 are coupled through Fermi resonance in pyridine and its complexes and the pressure dependence of the Fermi resonance constant W is calculated for Zn(py)2Cl2.The C-H stretching modes reflect the presence of more than one distinct pyridine group in the lattice and are of much lower intensity than in complexes where only one distinct pyridine group is found.
Crystal structures and polymorphism of nickel and copper coordination polymers with pyridine ligands
Krysiak, Yasar,Fink, Lothar,Bernert, Thomas,Glinnemann, Jürgen,Kapuscinski, Martin,Zhao, Haishuang,Alig, Edith,Schmidt, Martin U.
, p. 3190 - 3196 (2014)
The crystal structures of a series of pyridine coordination polymers [MII Cl2 (C5 H 5 N)x]n (M = Ni, Cu), prepared via thermal decomposition are reported. [NiCl2 (C5H5N) 4 ] (1) decomposes stepwise via [NiCl2 (C5H5N)2 ] n (2), [NiCl2(C5H5N)]n (3), and [NiCl2(C5H5N)2/3]n (4), to NiCl2 with increasing temperature. The thermal decomposition of [CuCl2 (C5H5N)2]n (5), progresses via two polymorphs of [CuCl2 (C5H5N)]n (6a and 6b), and [CuCl2(C5H5N)2/3]n (7), to CuCl2 . The compounds 3, 4, and 7 were prepared as pure phases. All crystal structures were determined by X-ray powder diffraction. Notably, the crystal structures of the polymorphs 6a and 6b were determined from powder diffraction data of a mixture of both phases. Crystal structures of [MIICl2(C5H5N)x]n with the same x, but different metal atoms (Ni, Cu) are homeotypic, compounds 4 and 7 are isotypic. Compounds with x = 1 (3, 6a, 6b) are composed of polymeric octahedra double chains 1∞[MCl3/3Cl2/2(C5H5N)] and in case of x = 2/3 (4, 7) of triple chains. The Jahn-Teller distortion in the copper compounds was observable with the pair distribution function (PDF) analysis.
Air-stable nickel precatalysts for fast and quantitative cross-coupling of aryl sulfamates with aryl neopentylglycolboronates at room temperature
Jezorek, Ryan L.,Zhang, Na,Leowanawat, Pawaret,Bunner, Matthew H.,Gutsche, Nicholas,Pesti, Aleksander K. R.,Olsen, James T.,Percec, Virgil
supporting information, p. 6326 - 6329 (2015/02/19)
A library containing 10 air-stable NiIIX(Aryl)(PCy3)2 complexes as precatalysts (X = Cl, Br, OTs, OMs, aryl = 1-naphthyl, 2-naphthyl; X = Cl, 1-acenaphthenyl, 1-(2-methoxynaphthyl), 9-phenanthrenyl, 9-anthracyl) was synthesized and demonstrated to quantitatively cross-couple 2-methoxyphenyl dimethylsulfamate with methyl 4-(5,5-dimethyl-1,3,2-dioxaborinane-2-yl)benzoate at 23 °C in dry THF in the presence of K3PO4(H2O)3.2 in less than 60 min. Lower or higher amounts of H2O in K3PO4 and as received THF mediate the same transformation in a maximum three times longer reaction time.
Synthetic analogs for evaluating the influence of N-H...S hydrogen bonds on the formation of thioester in acetyl coenzyme a synthase
Ariyananda, Piyal W. G.,Kieber-Emmons, Matthew T.,Yap, Glenn P. A.,Riordan, Charles G.
, p. 4359 - 4369 (2009/10/16)
A series of square planar methylnickel(II) complexes, (dppe)Ni(Me)(SAr) (dppe = 1,2-bis(diphenylphosphino)ethane); 2. Ar = phenyl; 3. Ar = pentafluorophenyl; 4. Ar = o-pivaloylaminophenyl; 5. Ar = p-pivaloylaminophenyl; (depe)Ni(Me)(SAr), (depe = 1,2-bis(diethylphosphino)ethane); 7. Ar = phenyl; 8. Ar = pentafluorophenyl; 9. Ar = o-pivaloylaminophenyl; 10. Ar = p-pivaloylaminophenyl), were synthesized via the reaction of (dppe)NiMe 2 (1) and (depe)NiMe2 (6) with either the corresponding thiol or disulfide. These complexes were characterized by various spectroscopic methods including 31P NMR, 1H NMR, 13C NMR and infrared spectroscopies and in most cases by X-ray diffraction analyses. Solid state and solution measurements establish that 4 and 9 contain intramolecular N-H...S bonds. Carbonylation of the complexes 2-4, 7-10 leads to (dRpe)Ni(CO)2 and MeC(O)SAr via the intermediacy of the acylnickel adducts, (dRpe)Ni(C(O)Me)(SAr), detected at low temperature by 31P NMR spectroscopy. Consistent with experimental observations, density functional theory results reveal that the intramolecular hydrogen bond in 9 stabilizes the acylnickel adduct compared with its non-hydrogen-bonded adduct, 10. Oxidative addition of MeC(O)SC6F5 to (dRpe)Ni(COD) followed by spontaneous decarbonylation proceeds in variable yields generating 3 and 8.
Hydromagnesation of Isoprene by Isopropylmagnesium Chloride in the Presence of Nickel(II) Compounds
Viktorov, N. B.,Zubritskii, L. M.
, p. 267 - 270 (2007/10/03)
The reaction of isoprene with alkylmagnesium halides in the presence of nickel complexes with phosphine oxides and nitrobgen-containing ligands gives dimeric hydromagnesation products along with monomeric magnesium-containing allyl-type products.
Solid, primary aliphatic amine complexes of transition-metal halides. I. Thermal studies on RNH2 complexes of nickel(II) chloride with R = H, CH3, CH3CH2, CH3(CH2)2, (CH3)2CH, CH3(CH2)3, (CH3)2CHCH2
Kenessey, G.,Liptay, G.
, p. 333 - 350 (2008/10/08)
The thermal decomposition characteristics of the ternary mixed, solid, primary aliphatic amine complexes formed with nickel(II) chloride was investigated by a simultaneous TG-DTG-DTA method. The course of the thermal decomposition is described in detail, results thus obtained are compared with the literature data and contradictions are pointed out. In addition to the complexes described in previous papers some new compounds and thermal intermediates have been prepared by solid-gas phase chemisorption and by freezing-out technique. Thermal intermediates containing two-third mole of the ligands, characteristic of the decomposition of pyridine type complexes of transition-metal halides, were identified during the degradation process.
