Mononuclear Ni(II)-Thiolate Complexes with Pendant Thiol and Dinuclear Ni(III/II)-Thiolate Complexes with Ni···Ni Interaction Regulated by the Oxidation Levels of Nickels and the Coordinated Ligands

Abstract

Compared to [Ni(II)(SePh)(P(o-C(6)H(3)-3-SiMe(3)-2-S)(2)(o-C(6)H(3)-3-SiMe(3)-2-SH))]- (1a) and [Ni(II)(Cl)(P(o-C(6)H(3)-3-SiMe(3)-2-S)(2)(o-C(6)H(3)-3-SiMe(3)-2-SH))]- (3a) with a combination of the intramolecular [Ni...H-S] and [Ni-S...H-S] interactions, complexes [NiII(SePh)(P(o-C(6)H(3)-3-SiMe(3)-2-S)(2)(o-C(6)H(3)-3-SiMe(3)-2-SH))]- (1b) and [Ni(II)(Cl)(P (o-C(6)H(3)-3-SiMe(3)-2-S)(2)(o-C(6)H(3)-3-SiMe(3)-2-SH))]- (3b) with intramolecular [Ni...H-S] interaction exhibit lower nu(S-H) stretching frequencies (2137 and 2235 cm(-1) for 1b and 3b vs 2250 and 2287 cm(-1) for 1a and 3a, respectively) and smaller torsion angles (27.2 degrees for 3b vs 58.9 and 59.1 degrees for 1a and 3a, respectively). The pendant thiol interaction modes of 1a, 3a, and 3b in the solid state are controlled by the solvent pairs of crystallization. Oxygen oxidation of dinuclear [Ni(II)(P(o-C(6)H(3)-3-SiMe(3)-2-S)(2)(o-C(6)H(3)-3-SiMe(3)-2-SH))](2) (4) yielded thermally stable dinuclear [Ni(III)(P(o-C(6)H(3)-3-SiMe(3)-2-S)(2)(o-C(6)H(3)-3-SiMe(3)-2-mu-S))](2) (5). The two paramagnetic d(7) Ni(III) cores (S = 1/2) with antiferromagnetic coupling (J = -3.13 cm(-1)) rationalize the diamagnetic property of 5. The fully delocalized mixed-valence [Ni(II)-Ni(III)] complexes [Ni2(P(o-C(6)H(3)-3-SiMe(3)-2-S)(3))(2)]- (6) and [Ni(2)(P(o-C(6)H(3)-3-SiMe(3)-2-S)(3))(P(o-C(6)H(3)-3-SiMe(3)-2-S)(2)(o-C(6)H(3)-3-SiMe(3)-2-SCH(3)))] (7) were isolated upon the reduction of 5 and the methylation of 6, respectively. The electronic perturbation from the sulfur methylation of 6 triggers the stronger Ni...Ni interaction and the geometrical rearrangement from the diamond shape of the [NiS(2)Ni] core to the butterfly structure of [Ni(mu-S)(2)Ni] to yield 7 with Ni...Ni distances of 2.6088(1) A. The distinctly different Ni...Ni distances (2.6026(7) for 5 and 2.8289(15) A for 6) and the coordination number of the nickels indicate a balance of geometrical requirements for different oxidation levels of [PS(3)Ni-NiPS(3)] cores of 5 and 6.

Binuclear, High‐Valent Nickel Complexes: Ni−Ni Bonds in Aryl–Halogen Bond Formation

“…In contrast to Pd, few binuclear Ni compounds have been isolated and studied in the context of reductive elimination. Only one precedent of a binuclear Ni III ‐Ni III complex exists, along with a few examples of mixed‐valent Ni 2 5+ complexes . The majority of these inorganic complexes are stabilized by “paddle‐wheel” geometries, but do not mediate bond‐formation reactions.…”

Binuclear, High‐Valent Nickel Complexes: Ni−Ni Bonds in Aryl–Halogen Bond Formation

“…[8b, 9] In contrast to Pd, few binuclear Ni compounds have been isolated and studied in the context of reductive elimination. Only one precedent of abinuclear Ni III -Ni III complex exists, [10] along with afew examples of mixed-valent Ni 2 5+ complexes. [11] Them ajority of these inorganic complexes are stabilized by "paddle-wheel" geometries,but do not mediate bond-formation reactions.H erein, we present the synthesis of binuclear mixed-valent and high-valent, organometallic Ni complexes, which undergo rapid reductive elimination to form carbonhalogen bonds even at À80 8 8C.…”

Synthesis, Characterization and Biological Studies of Adducts of Nickel(II)thioxanthates with Substituted Pyridines

“…These three bands may be assigned to three spin allowed transitions 3 ) respectively. The appearance of these bands along with shoulders suggest that the adducts synthesized have distorted octahedral geometry around Ni(II) metal ion 24 . Vibrational spectral data in cm …”