[Ni5(SEt)10] und [Ni4(SC6H11)8], homoleptische Nickel-Thiolate mit pentagonal-prismatischen und cubanartigen Schwefelgerüsten /[Ni5(SEt)10] and [Ni4(SC6H11)8], Homoleptic Nickel-Thiolates with Pentagonal-Prismatic and Cubane-Like Sulfur Frameworks

Abstract

NiCl2 reacts with NaSR in methanol solution to give the black diamagnetic complexes [Ni5(SR)₁₀] (R = Et, 1) and [Ni4(SR)₈] (R = C₆H₁₁ , 2). Crystals of 1 are monoclinic, space group P2₁/h with a = 13.149(4), b = 15.571(4), c = 17.917(5) Å , β = 105.31(2)° and Z = 4. 2 crystallizes from methylene chloride with sixteen solvent molecules per unit cell in the orthorhombic space group Ibca with a = 17.902(8), b = 18.289(8), c = 37.99(2) Å and Z = 8. The structures of 1 and [Ni₄(SC₆HM)₈] · 2 CH ₂Cl₂ (3) have been determined by X-ray crystallography and refined to R(R_W) = 0.072 (0.062) and 0.119 (0.128), respectively. Both complexes are cyclic neutral molecules and contain square planar NiS₄ coordination sites (1: mean Ni - S 2.200 Å , mean S -Ni -S 81.8 ( 2 x ) . 98.3 ( 2 x ) , 170.8° ( 2 x ) ; 2: mean Ni - S 2.213 Å , mean S - Ni - S 80.9 (2 x ) , 98.2 ( 2 x ) , 167.5°(2 x )) condensed via opposite edges. A s a result, prismatic sulfur frameworks are observed which are pentagonal in the case of 1 and tetragonal in the case of 2. Their lateral faces are centered by Ni atoms. The symmetry of the Ni-S core portion approaches D_5h for 1 and D_4h for 2. With reference to the toroidal N i-S frameworks, the sulfur-carbon bonds of each pair of opposite ligands are in axial and equatorial positions, respectively. This configuration alternates around the prismatic sulfur arrangement which is completely compatible with the even number of nickel atoms present in 2, but results in a node for 1 due to the five-fold symmetry.