14647-23-5Relevant articles and documents
Catecholato complexes of cobalt and nickel with 1,4-disubstituted-1,4-diazabutadiens-1,3 and 1,2-bis(diphenylphosphino)ethane
Bubnov, Michael P.,Teplova, Irina A.,Druzhkov, Nikolay O.,Fukin, Georgy K.,Cherkasova, Anna V.,Cherkasov, Vladimir K.
, p. 527 - 535 (2015)
Divalent cobalt and nickel form four-coordinate complexes with sterically hindered 3,6-di-tert-butylcatecholato dianion (3,6-DBCat) and neutral bidentate 1,4-disubstituted-1,4-diazabutadiens-1,3 (DAB). Structural study of (1,4-di-tert-butyl-1,4-diazabutadiene-1,3)(3,6-di-tert-butyl-catecolato)nickel and (1,4-bis-(2,6-di-iso-propylphenyl)-2,3-dimethyl-1,4-diazabutadiene-1,3)(3,6-di-tert-butyl-catecolato)cobalt indicates square-planar environment of metals. Chemical one-electron oxidation of nickel complexes proceeds through catecholate ligand and leads to o-semiquinonato adducts. EPR spectral parameters indicate preservation of square-planar configuration after oxidation. Complexes (DAB)M(Cat) (M = Ni, Co) undergo neutral ligand substitution reactions. [Figure not available: see fulltext.]
Synthesis and structure of the Novel 11-vertex rhenacarborane dianion [1,1,1-(CO)3-2-Ph-closo-1,2-ReCB9H9] 2- and its reactivity toward cationic transition metal fragments
Du, Shaowu,Kautz, Jason A.,McGrath, Thomas D.,Stone, F. Gordon A.
, p. 2842 - 2850 (2003)
Treatment of [NEt4] [6-Ph-nodo-6-CB9H11] in tetrahydrofuran (THF) with BunLi (2 equiv) followed by [ReBr(THF)2(CO)3] gives the title rhenacarborane dianion isolated, by addition of [N(PPh3)2]Cl, as a mixed salt [N(PPh3)2][NEt4][1,1,1-(CO) 3-2-Ph-closo-1,2-ReCB9H9], whose structure was confirmed by X-ray diffraction. The closo 11-vertex dianion reacts readily with several cationic transition metal-ligand fragments, affording products with novel structures in which the electrophilic metal groups are attached exo-polyhedrally to the {closo-1,2-ReCB9} cage system by rhenium-metal bonds supported by three-center two-electron B-H-M linkages. Species prepared include [1,3-{M(dppe)}-3-μ-H-1,1,1-(CO) 3-2-Ph- closo-1,2-ReCB9H8] (M = Ni, Pd, or Pt; dppe = Ph 2PCH2CH2PPh2), N(PPh 3)2][1,3,6-{M(CO)3}-3,6-(μ-H) 2-1,1,1-(CO)3-2-Ph-closo-1,2-ReCB9H 7] (M = Mn or Re), and [1,6-{M(PPh3)}-1,7-{M(PPh 3)}-6,7-(μ-H)2-1,1,1-(CO) 3-2-Ph-closo-1,2- ReCB9H7] (M = Cu or Au). Of these, the structures of the platinum-rhenium and dicopper-rhenium species were confirmed by X-ray diffraction.
Kinetics of the Homogeneous and Heterogeneous Coupling of Furfural with Biomass-Derived Alcohols
Goulas, Konstantinos A.,Gokhale, Amit A.
, p. 2387 - 2393 (2018)
The tandem dehydrogenation and aldol condensation of butanol with furfural was investigated over homogeneous and heterogeneous catalysts using kinetics and isotope effects. In the homogeneous system, Ni(dppe)Cl2 catalyzes the transfer dehydrogenation of butanol to the furfural, whereas the aldol condensation of butyraldehyde and furfural takes place over the basic K2CO3 cocatalyst. In the heterogeneous system, a transition-metal-free mixed Mg–Al oxide, both the transfer hydrogenation and aldol condensation take place over the basic sites of the catalyst, and the rate-determining step is the alpha-hydride transfer from the butanol to the furfural.
Preparation and structure of nickel complex Ni(dppe)Cl2
Gao, Wei,Li, Kai,Wang, Xin-Ling
, p. 7876 - 7878 (2013)
Mononuclear nickel complex Ni(dppe)Cl2 (dppe = Ph 2PCH2CH2PPh2) was prepared by reaction of NiCl2·6H2O and dppe in CH 2Cl2/methanol solution and its structure was determined by single crystal X-ray diffraction analysis. The crystals are monoclinic, space group P21/c with a = 12.228(3), b = 15.235(4), c = 15.294(4) A?, α = 90.00, β = 105.933(4), γ= 90.00°, V = 2739.7(13) A?3, Z = 4, F(000) = 1256, Dc = 1.486 g/cm3, μ = 1.231 cm-1, the final R = 0.0543 and wR = 0.1297. A total of 28157 reflections were collected, of which 6516 were independent (Rint = 0.0620).
A new polymorph, form C, of [1,2-bis(diphenylphosphino)ethane]-dichloronickel(II)
Davison, Jo C.,Foreman, Mark R. St. J.,Howie, R. Alan,Plater, M. John,Skakle, Janet M. S.
, p. 690 - 693 (2001)
The title compound, [NiCl2(C26H24P2)], has arisen as a result of the unexpected reduction (hydrogenation) of the trans-1.2-bis(diphenylphosphino)ethene ligand. The hydrothermal reaction conditions have produced a third polymorphic form of the compound which has twofold symmetry, crystallizes in an enantiomer-selective manner and contains an unexpectedly short C-C (ethane) bond. Contacts of the form C-H···Cl are present, one involving alkyl and the other aryl hydrogen, with C···Cl distance of 3.556 (4) and 3.664 (6) A, respectively.
A Mild One-Pot Reduction of Phosphine(V) Oxides Affording Phosphines(III) and Their Metal Catalysts
Kapu?niak, ?ukasz,Plessow, Philipp N.,Trzybiński, Damian,Wo?niak, Krzysztof,Hofmann, Peter,Jolly, Phillip Iain
, p. 693 - 701 (2021/04/06)
The metal-free reduction of a range of phosphine(V) oxides employing oxalyl chloride as an activating agent and hexachlorodisilane as reducing reagent has been achieved under mild reaction conditions. The method was successfully applied to the reduction of industrial waste byproduct triphenylphosphine(V) oxide, closing the phosphorus cycle to cleanly regenerate triphenylphosphine(III). Mechanistic studies and quantum chemical calculations support the attack of the dissociated chloride anion of intermediated phosphonium salt at the silicon of the disilane as the rate-limiting step for deprotection. The exquisite purity of the resultant phosphine(III) ligands after the simple removal of volatiles under reduced pressure circumvents laborious purification prior to metalation and has permitted the facile formation of important transition metal catalysts.
Efficient catalytic transfer hydrogenation reactions of carbonyl compounds by Ni(II)-diphosphine complexes
Venkatesh, Sadhana,Panicker, Rakesh R.,Lenin Kumar, Verdhi,Pavankumar,Viswanath, Nukala,Singh, Shangrila,Desikan, Rajagopal,Sivaramakrishna, Akella
, p. 2963 - 2977 (2020/11/03)
The catalytic transfer hydrogenation reactions of a series of aromatic and aliphatic carbonyl compounds were investigated using divalent Ni(II)-diphosphine complexes, [L2NiCl2] (where L2 = 1,1-bis(diphenylphosphino)methane (dppm), 1,2-bis(diphenylphosphino)ethane (dppe), 1,3-bis(diphenylphosphino)propane (dppp), 1,1-bis(diphenylphosphino)ferrocene (dppf), and N-butyl-N-(diphenylphosphino)-1,1-diphenylphosphinamine (dppba)). This is a single-step reaction in the presence of potassium hydroxide and isopropyl alcohol to afford the corresponding alcohols. This protocol tolerates other sensitive functional groups like olefinic double bonds and also achieves high chemoselectivity. All the reactions were monitored by GC and GC–MS. The plausible mechanism is also discussed. The method reported in the present article is simple, cost-effective, and provides excellent conversions. Nickel-diphosphine complexes appear as a potential alternative to expensive transition metal complexes.
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.
NICKEL PRE-CATALYSTS AND RELATED COMPOSITIONS AND METHODS
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Page/Page column 40, (2015/05/26)
Described herein are nickel pre-catalysts and related compositions and methods. The nickel pre-catalysts may be activated to form catalysts which may be utilized in organic reactions.
Trap-Free Halogen Photoelimination from Mononuclear Ni(III) Complexes
Hwang, Seung Jun,Powers, David C.,Maher, Andrew G.,Anderson, Bryce L.,Hadt, Ryan G.,Zheng, Shao-Liang,Chen, Yu-Sheng,Nocera, Daniel G.
supporting information, p. 6472 - 6475 (2015/06/08)
Halogen photoelimination reactions constitute the oxidative half-reaction of closed HX-splitting energy storage cycles. Here, we report high-yielding, endothermic Cl2 photoelimination chemistry from mononuclear Ni(III) complexes. On the basis of time-resolved spectroscopy and steady-state photocrystallography experiments, a mechanism involving ligand-assisted halogen elimination is proposed. Employing ancillary ligands to promote elimination offers a strategy to circumvent the inherently short-lived excited states of 3d metal complexes for the activation of thermodynamically challenging bonds.
