Multimetallic Complexes and Functionalized Nanoparticles Based on Unsymmetrical Dithiocarbamate Ligands with Allyl and Propargyl Functionality

The new, unsymmetrical dithiocarbamate ligands, KS2CN­(CH2CHCH2)­Me and KS2CN­(CH2CCH)­Me, are formed from the respective amines on reaction with KOH and carbon disulfide. The homoleptic complexes [Ni­{S2CN­(CH2CHCH2)­Me}2] and [M­{S2CN­(CH2CCH)­Me}2] (M = Ni, Pd, Pt) are formed on reaction with suitable metal precursors. Conversion between the two pendant functionalities was confirmed by hydrogenation of [Ni­{S2CN­(CH2CCH)­Me}2] to yield [Ni­{S2CN­(CH2CHCH2)­Me}2]. The monodithiocarbamate compounds of group 8, 10, and 11 metals, [Ru­{S2CN­(CH2CHCH2)­Me}­(dppm)2]+, [Ru­(CHCHC6H4Me-4)­{S2CN­(CH2CHCH2)­Me}­(CO)­(PPh3)2], [Ni­{S2CN­(CH2CHCH2)­Me}­(dppp)]+, and [Au­{S2CN­(CH2CHCH2)­Me}­(PPh3)] were formed successfully. Using KS2CN­(CH2CCH)­Me, the complex [Ru­{S2CN­(CH2CCH)­Me}­(dppm)2]+ was obtained from cis-[RuCl2(dppm)2]. One palladium example, [Pd­{S2CN­(CH2CCH)­Me}­(PPh3)2]+, was also isolated in low yield. However, under the typical conditions employed, a rearrangement reaction prevented isolation of further group 10 propargyl-dithiocarbamate products. Over the extended reaction time required, Me­(HCCCH2)­NCS2– was found to undergo a remarkable, atom-efficient cyclization to form the thiazolidine-2-thione, H2CCCH2N­(Me)­C­(S)­S, in high yield, with MeCCHN­(Me)­C­(S)­S as the minor product. The reactivity of the pendant triple bonds in [Ni­{S2CN­(CH2CCH)­Me}2] was probed in the reaction with [RuH­(CO)­(S2P­(OEt)2)­(PPh3)2] to form the trimetallic example [Ni­{S2CN­(Me)­CH2CHCHRu­(CO)­(S2P­(OEt)2)­(PPh3)2}2], while the copper­(I) catalyzed reaction with benzylazide yielded the triazole product, [Ni­{S2CN­(Me)­CH2(C2HN3)­Bz}2]. KS2CN­(CH2CCH)­Me was also used to prepare the gold nanoparticles, Au@S2CN­(CH2CCH)­Me. Structural studies are reported for [Ru­(CHCHC6H4Me-4)­{S2CN­(CH2CHCH2)­Me}­(CO)­(PPh3)2] and [Ru­{S2CN­(CH2CCH)­Me}­(dppm)2]­PF6.