
TY  - JOUR
A1  - Snyder, BS 
A1  - Rao, CP 
A1  - Holm, RH 
T1  - Mononuclear and Binuclear Metal(II) Complexes of Ethane-1,2-Dithiolate. Preparation, Equilibrium and Redox Properties of [Ni(S<sub>2</sub>C<sub>2</sub>H<sub>4</sub>)<sub>2</sub>]<sup>2-</sup> and [Ni<sub>2</sub>(S<sub>2</sub>C<sub>2</sub>H<sub>4</sub>)<sub>3</sub>]<sup>2-</sup>, and the Structures of Ni<sub>2</sub>(S<sub>2</sub>C<sub>2</sub>H<sub>4</sub>)<sub>3</sub>]<sup>2-</sup> and [Pd(S<sub>2</sub>C<sub>2</sub>H<sub>4</sub>)<sub>2</sub>]<sup>2-</sup>
JF  - Australian Journal of Chemistry
JO  - Aust. J. Chem.
Y1  - 1986
VL  - 39
IS  - 7
SP  - 963
EP  - 974
KW  - 
UR  - https://doi.org/10.1071/CH9860963 
N2  - The diamagnetic ethane-1,2-dithiolate complexes [Ni( edt )2]2- and [Ni2( edt )3]2- were isolated as Ph4P+ salts from reaction systems with K2( edt ) : NiCl2 mol ratios of 10 : 1 and 2 : 1, respectively. (Ph4P)2[Ni2( edt )3] crystallizes in triclinic space group P&#299; with a 10.409(2)&#506;, b 12.872(4)&#506;, c 21.235(6)&#506;, &#945; 76.59(2)&#176;, &#946; 84.65(2)&#176;, &#947; 70.12(2)&#176;, and Z 2. The anion consists of a Ni( edt ) fragment bridged to [Ni( edt )2]2- through cis sulfur atoms of different chelate rings, resulting in a complex of idealized CS symmetry. Each NiS4 coordination unit shows small deviations from planarity. Their mean S4 planes are inclined at a dihedral angle of 118.0&#176; across the S-S vector of bridging sulfur atoms, which leads to a Ni-Ni separation of 2.914(1)&#506;. Terminal Ni-S bond lengths average to 2.177(12)&#506;. (Ph4P)2[Pd( edt )2].4H2O crystallizes in monoclinic space group C2/c with a 10.470(3)&#506;, b 24.264(9)&#506;, c 19.691(7)&#506;, &#946; 93.05(3)&#176;, and Z 4. The PdS4 unit of the anion deviates from planarity by a dihedral angle of 7.7&#176; between chelated PdS2 groups. The mean Pd-S distance is 2.318 &#506;. In protic and aprotic solvents [Ni( edt )2]2- converts into the binuclear complex in the reaction 2[Ni( edt )2]2- &#8594; [Ni2( edt )3]2- + edt2-, which is first order in the mononuclear complex. Reactions are faster in protic solvents; in HCONMe2 at 40&#176;C k &#8776; 4&#215;10-5 s-1. In acetonitrile [Ni2( edt )3]2- shows an irreversible oxidation at Ep,a -0.21 V v . s.c.e .; for [Ni( edt )2]2- under the same conditions Ep,a -0.61 V and E1/2 for the 2-/1- couple is estimated as -0.68 V. These values demonstrate that potentials of classical anionic NiII  tetrathiolate complexes are substantially reduced relative to those of non- thiolate species (excluding dithiolenes ), and are in the region of NiII /III potentials in hydrogenases. 
ER  -

