90668-33-0Relevant academic research and scientific papers
Preparation and Properties of Bisdinickel(+1) Ion, a Novel Unsymmetrical Thiolate-bridged Complex
Pfeiffer, Ernst,Pasquier, Maurice L.,Marty, Werner
, p. 654 - 663 (1984)
The title cation( =Ni2L31+ ) is formed in a variety of reactions (Schemes 1 and 2) in systems containing Ni2+ and (2-thiolatoethyl)-diphenylphosphine ( =L- ) in the absence of coordinating anions at Ni2+/L- ratios >0.5 in apolar or moderately polar media.Solid ClO4 and BPh4 have been isolated.Job's plots confirm the Ni2L3+-stoichiometry in solution. 31P-NMR data are consistent with >/= 97 percent Ni2L3+ (vs. 2+) at equilibrium and support the suggested configuration (Fig.2).The equilibrium between NiL2 + NiL2Br2 and Ni2L3+ + Br- varies with the solvent composition in CH2Cl2/EtOH mixtures.The rate of formation of Ni2L2Br2 from Ni2L3+ and bromide (in high excess) in CH2Cl2 is first-order in +>tot but depends on the ratio tot/tot, even at a high excess of bromide.This is interpreted by efficient competition in ion-aggregate formation between the small perchlorate concentration introduced as the counterion of Ni2L3+, and the large excess of bromide.
Organometallic chemistry of sulfur/phosphorus donor ligand complexes of nickel(II) and nickel(0)
Hsiao, Yui-May,Chojnacki, Stephen S.,Hinton, Pamela,Reibenspies, Joseph H.,Darensbourg, Marcetta Y.
, p. 870 - 875 (1993)
The X-ray crystal structures and electrochemical properties as well as chemical reactivity of the thioether complexes [Ni(Ph2PCH2CH2SEt)2][BF 4]2 (5) and [Ni(Ph2PCH2CH2SCH2CH 2CH2SCH2CH2PPh2)][BF 4]2 (6), [Ni(PSSP)]2+, are compared with the thiolate Ni(Ph2PCH2CH2S)2 (4). Complex 4 crystallized in the orthorhombic space group Pbca (No. 61) with a = 9.204(2) ?, b = 15.766(3) ?, c = 17.177(3) ?, V = 2492.6(8) ?3, Z = 4, and final R = 0.050 (Rw = 0.050) for 2212 unique reflections. Complex 5 crystallized in the monoclinic space group P21/c, with a = 10.267(2) ?, b = 13.102(2) ?, c = 13.263(2) ?, β = 93.750(10)°, V = 1780.3(5) ?3, Z = 2, and final R = 0.076 (Rw = 0.072) for 1777 unique reflections. The square-planar structures of 4 and 5 have sulfur donors in a trans arrangement and show a 0.04-? lengthening of both the Ni-S and Ni-P bonds on going from the thiolate to the thioether complex. Within the CH3CN solvent window, the cyclic voltammograms of 5 and 6 show two reversible redox events assigned to NiII/I and NiI/0, whereas the thiolate 4 shows only a sulfur-based irreversible oxidation and no reduction. Complexes 5 and 6 can be chemically reduced to Ni0 species, 5R and 6R, with Na/Hg amalgam. The 1H NMR spectra of the reduced complexes indicate loss of one thioether donor for 5R and both for 6R. Protonation of the reduced species produced a Ni-H and reaction with both CH3I or CH3C(=O)Cl gave rise to Ni-CH3 and NiC(O)CH3 functionalities, respectively. The tetradentate derivatives [HNi(PSSP)]+ and [CH3Ni(PSSP)]+ are more stable than their bidentate analogues and show loss of reversible redox activity; i.e., the cyclic voltammograms find no evidence for stable NiI-H or NiI-CH3, or for NiIII-H or NiIII-CH3 species. The NiC(O)CH3 compounds rapidly and reversibly decarbonylate in solution (at temperatures >-30°C). A contrast of the abilities of structurally analogous P-SR vs N-SR ligands to stabilize subvalent nickel and organonickel functionalities is made.
Light induced sulfur-dealkylation of phosphino-thioether nickel(0) complexes
Kim, Jang Sub,Reibenspies, Joseph H.,Darensbourg, Marcetta Y.
, p. 283 - 294 (2008/10/08)
The observation of homolytic S-CH3 bond cleavage in (Ph2P(o-C6H4)SCH3) 2Ni0 under photochemical conditions has prompted further investigation of nickel(0) complexes and their stability. Tetradentate P2S′2 donor ligands (S′ = thioether type S donor) with aromatic rings incorporated into the P to S links, Ph2P(o-C6H4)S(CH2) 3S(o-C6H4)PPh2 (arom-PSSP), or the S to S links, Ph2P(CH2)2SCH2(o-C6H 4) CH2S (CH2)2PPh2 (PS-xy-SP), have been used to form four-coordinate, square planar nickel (II) complexes, [(arom-PSSP)Ni] (BF4)2 (2) and [(PS-xy-SP)Ni] (BF4)2 (3). The bidentate and tetradentate ligands, Ph2P(o-C6H4)SCH2CH3 (arom-PSEt) and Ph2P(CH2)2S(CH2) 3S(CH2)2PPh2 (PSSP), give similar complexes, [(arom-PSEt)2Ni] (BF4)2 (1) and [(PSSP)Ni] (BF4)2 (4), respectively. Cyclic voltammograms of the NiII complexes in CH3CN show two reversible redox events assigned to NiII/I and NiI/0. The one-electron reduction product produced by stoichiometric amounts of Cp2Co can be characterized by EPR. At 100 K rhombic signals show hyperfine coupling to two phosphorus atoms. Complete bulk chemical reduction of complexes 1, 2, 3 and 4 with Na/Hg amalgam provided the corresponding nickel(0) complexes 1R, 2R, 3R and 4R which were isolated as red solutions or solids and characterized by magnetic resonance properties and reaction products. Photolysis of these nickel(0) complexes leads to S-dealkylation to produce alkyl radicals and dithiolate nickel(II) complexes. Complex 3 crystallized in the monoclinic space group P21/c with a = 20.740(5), b = 9.879(3), c = 17.801(4) ?, β = 92.59(2)°, V = 3644(2) ?3 and Z=4; complex 4: P21 with a = 13.815(4), b = 13.815(4), c = 15.457(5) ?, β = 104.89(2)°, V = 3365.4(14) ?3 and Z = 4.
