UC Santa Barbara

Treatment of the Ni(II) chloride complexes, [LRNiIICl] (LR = {(2,6-iPr2C6H3)NC(R)}2CH, R = Me, tBu) with 1 equiv of KSCPh3 affords the Ni(II) triphenylmethylthiolate complexes, [LRNiII(SCPh3)], in good yields. The reaction of [LRNiII(SCPh3)] with 2 equiv of KC8 and L (L = 18-crown-6 or 2,2,2-cryptand) affords both [K(L)][LRNiII(S)] and [K(L)][CPh3] via reductive deprotection of the triphenylmethyl group. Treatment of [K(18-crown-6)][LtBuNiII(S)] with Ph2SiH2 affords a Ni(I) SH- complex, [K(18-crown-6)][LtBuNiI(SH)]. Treatment of [K(18-crown-6)][LtBuNiII(S)] with Me3SiOTf affords a Ni(II) trimethylsilanethiolato complex [LtBuNiII(SSiMe3)].

Treatment of [LtBuNiII(SCPh3)] with 2 equiv of decamethylcobaltocene (Cp*2Co) generates a transient NiII sulfide complex, [Cp*2Co][LtBuNiII(S)]. A subsequent deprotonation of [Cp*2Co]+ by [CPh3]- gives the CoI fulvenyl complex, [Cp*Co(C5Me4CH2)], which couples with the sulfide ligand in [Cp*2Co][LtBuNiII(S)] to form a Ni(I) cobaltocenium thiolate complex, [LtBuNiI(SCH2Me4C5)Co(Cp*)], concomitant with the reduction of the cobaltocenium cation.

Treatment of [K(18-crown-6)][LtBuNiII(S)] with CS2 yields the Ni(II) trithiocarbonate complex, [K(18-crown-6)][LtBuNiII(S,S:2-CS3)]. Treatment of [K(2,2,2-cryptand)][LtBuNiII(S)] with CS2 generates the double insertion product, a Ni(II) trithiocarbonate dithiocarboxylate complex, [K(2,2,2-cryptand)][(S,S:2-CS3)NiII{S,S:2-CS2(LtBu)}].

Treatment of [K(18-crown-6)][LtBuNiII(S)] with CO affords a Ni(II) carbonyl sulfide complex, [K(18-crown-6)][LtBuNiII(S,C:η2-SCO]. Treatment of [K(18-crown-6)][LtBuNiII(S)] with NO yields a nickel nitrosyl complex, [LtBuNi(NO)], and a perthionitrite salt, [K(18-crown-6)][SSNO].

Treatment of [K(18-crown-6)][LtBuNiII(S)] with N2O yields an unprecedented Ni(II) thiohyponitrite complex, [K(18-crown-6)][LtBuNiII(2-SNNO)]. Gentle thermolysis of [K(18-crown-6)][LtBuNiII(2-SNNO)] results in extrusion of N2 and formation of a thioperoxide complex, [K(18-crown-6)][LtBuNiII(2-SO)]. Treatment of [K(18-crown-6)][LtBuNiII(2-SO)] with CO, forms [K(18-crown-6)][LtBuNiII(S)] along with CO2, via O-atom abstraction. The Ni(II) sulfide then reacts with CO or CO2 to form [K(18-crown-6)][LtBuNiII(2-SCO)] and [K(18-crown-6)][LtBuNi(S,O:κ2-SCO2)], respectively. The thioperoxide complex, [K(18-crown-6)][LtBuNiII(2-SO)], can also react with the newly formed CO2 to form a putative monothiopercarbonate complex, [K(18-crown-6)][LtBuNiII(2-SOCO2)], which can then transfer an S atom to CO, forming COS and [K(18-crown-6)][LtBuNiII(2-CO3)].