Multifunctional Dithiocarbamates: Synthesis and Ring-Closing Metathesis of Diallyldithiocarbamate Complexes

The complex cis-[RuCl2(dppm)2] reacts with the diallyldithiocarbamate KS2CN(CH2CHCH2)2 to form [Ru{S2CN(CH2CHCH2)2}(dppm)2]+. The same ligand was also used to prepare the alkenyl complexes [RuR{S2CN(CH2CHCH2)2}(CO)(PPh3)2] (R = CHCHBut, CHCHC6H4Me-4, C(CCBut)CHBut) from the corresponding precursors [RuRCl(CO)(BTD)(PPh3)2] (BTD = 2,1,3-benzothiadiazole) and [Ru(C(CCBut)CHBut)Cl(CO)(PPh3)2]. The complexes [Ni{S2CN(CH2CHCH2)2}(dppp)]+ (dppp =1,3-bis(diphenylphosphino)propane) and [M{S2CN(CH2CHCH2)2}(dppf)]+ (M = Ni, Pd, Pt; dppf = 1,1′-bis(diphenylphosphino)ferrocene) were prepared from the respective precursors [MCl2(L2)] (L2 = dppp, dppf) and KS2CN(CH2CHCH2)2 in the presence of NH4PF6. In a similar manner, treatment of the cyclometalated dimer [Pd(C,N-CH2C6H4NMe2)Cl]2 with the dithiocarbamate ligand yielded [Pd(C,N-CH2C6H4NMe2){S2CN(CH2CHCH2)2}]. The homoleptic literature complexes [Ni{S2CN(CH2CHCH2)2}2] and [Co{S2CN(CH2CHCH2)2}3] were also prepared and characterized. Ring-closing metathesis catalyzed by [Ru(CHPh)Cl2(SIMes)(PCy3)] converted [Ni{S2CN(CH2CHCH2)2}2], [Pd(C,N-CH2C6H4NMe2){S2CN(CH2CHCH2)2}], [Ni{S2CN(CH2CHCH2)2}(dppp)]+, [Pt{S2CN(CH2CHCH2)2}(dppf)]+, [Ru{S2CN(CH2CHCH2)2}(dppm)2]+, and [Ru(CHCHC6H4Me-4){S2CN(CH2CHCH2)2}(CO)(PPh3)2] into the corresponding 3-pyrroline dithiocarbamate compounds [Ni(S2CNC4H6)2], [Pd(C,N-CH2C6H4NMe2)(S2CNC4H6)], [Ni(S2CNC4H6)(dppp)]+, [Pt(S2CNC4H6)(dppf)]+, [Ru(S2CNC4H6)(dppm)2]+, and [Ru(CHCHC6H4Me-4)(S2CNC4H6)(CO)(PPh3)2], respectively. These complexes were also directly prepared from the reaction of the appropriate starting materials with preformed KS2CNC4H6. The more sterically crowded complex [Co{S2CN(CH2CHCH2)2}3] failed to give a reaction with the metathesis catalyst, although it could be prepared directly from KS2CNC4H6 and cobalt acetate. The compounds [Ru(CHCHC6H4Me-4){S2CN(CH2CHCH2)2}(CO)(PPh3)2], [Ni{S2CN(CH2CHCH2)2}(dppp)]PF6, and [Ni(S2CNC4H6)(dppp)]PF6 were characterized crystallographically.