Synthesis of a Masked Terminal Nickel(II) Sulfide by Reductive Deprotection and its Reaction with Nitrous Oxide

The addition of 1 equiv of KSCPh3 to [(LNiCl)-Ni-R] (L-R ={(2,6-iPr(2)C(6)H(3))NC(R)}(2)CH; R=Me, tBu) in C6H6 results in the formation of [(LNi)-Ni-R(SCPh3)] (1: R=Me; 2: R=tBu) in good yields. Subsequent reduction of 1 and 2 with 2 equiv of KC8 in cold (-25 degrees C) Et2O in the presence of 2 equiv of 18-crown-6 results in the formation of masked terminal Ni-II sulfides, [K(18-crown-6)][(LNi)-Ni-R(S)] (3: R=Me; 4: R= tBu), also in good yields. An X-ray crystallographic analysis of these complexes suggests that they feature partial multiple-bond character in their Ni-S linkages. Addition of N2O to a toluene solution of 4 provides [K(18-crown-6)][(LNi)-Ni-tBu(SN= NO)], which features the first example of a thiohyponitrite (kappa(2)-[SN=NO](2-)) ligand.