1 Nickel

Chelate complex Ni(S2C2H2)2 as a molecular model of the hydrodesulfurization active center

“…1). Actually, nickel (IV) complexes are diamagnetic and have a strong tendency to octahedral geometry [8,9] with 10 Dq = 20,000 cm 1 for NiF62- [10]. This value is higher than that of Ni(II): 10 Dq = 7250 cm "1 for NiF64 [11 ].…”

Organobimetallic Nickel‐Iron Complexes, Valence Tautomer or Charge Localized Ferrocene Ligands Upon Oxidation

“…The molecular structures of [1] + and [2] + were used for the input of the DFT analysis and the calculated bond lengths are in good agreement with those found in the molecular structure. (Calculations for [3] + and all oxidation states were deemed unnecessary. Due to minor differences between [2] + and [3] + , additionally [2] + contains fewer atoms making it practical for calculations.…”

“…Organonickel compounds, especially those found in catalytic transformation, are most often described going through the Ni II /Ni 0 redox states; [1][2] while the odd-electron Ni I /Ni III species are still uncommon but increasingly important oxidation states. [3][4][5][6][7][8][9] The Ni I /Ni III states are important in many nickelenzymes, especially when the nickel is part of a bimetallic or higher order cluster, such as NiFe-hydrogenase, CO-oxidoreductase, or the Ni III in Ni-superoxide dismutase (Scheme 1). [10][11][12] These clusters/non-innocent ligands distribute the charge buildup over several sites and in turn flattens the energy profile the redox-exchange.…”

“…[23] This type of non-innocent behavior for dppf has also been previously described. [23][24][25][26] www.eurjic.org volume of the nickel site (%V bur ) [27] is minor where [1] + (93.4 %) is ~2 % less buried than [2] + (95.1 %) and [3] + (95.4 %).…”

Oxidative addition of dihydrogen to Ni(II) complexes.ab initio MO/MP4 calculations of the electronic structure of NiH2Cl2(PH3)2 complex

“…3 -TS-HH and TS-HC1. The activation barrier values (Eac= 120 -160 kJ/mol) calculated at the MP4 level (Table 1) dx2-y2 So far, it is believed that the Ni(IV) oxidation state is possible for the square planar Ni(SzCzR2)2 complex [22]. However, detailed quantum-chemical calculations of the electronic structure of Ni(S2CEH2)z show that a d 8 Ni(II) diamagnetic singlet is the ground state in this complex [23,24].…”