The synthesis and reactivity of heterodinuclear iron, ruthenium, and cobalt compounds containing bridging dithiomethylene ligands. Attempted synthesis of the iron carbyne compound Cp(CO)Fe(triple bond)CSCH3

Abstract

<p>Part I of this dissertation involves studying the reactivity of cati- onic dithiocarbene complexes of iron and ruthenium toward metal carbonyl anions. The cationic terminal dithiocarbene complex Cp(CO)(NCCH(,3))Fe C(SCH(,3))(,2) PF(,6) reacts with Na Co(CO)(,4) in THF to yield the bridging heterodinuclear (mu)-dithioalkoxymethylene compound Cp(CO)Fe((mu)-CO)((mu)-C(SCH(,3))(,2))Co(CO)(,2). An X-ray structure of this compound indicates a sulfur atom of the (mu)-methylene ligand is bonded to Co forming a three-membered metallothiocyclopropane ring. A molecular orbital calculation was carried out to provide insight into the interactions that stabilize this unusual (mu)-methylene ligand. The cyclic 5 and 6 membered dithiocarbene compounds Cp(CO)- (NCCH(,3))Fe C(S(CH(,2))(,n)S PF(,6) (n = 2,3) and the ruthenium carbene Cp(CO)(NCCH(,3))Ru C(SCH(,3))(,2) PF(,6) react in an analogous fashion giving the (mu)-dithiomethylene compounds Cp(CO)Fe((mu)-CO)((mu)-CS(CH(,2))(,n)S)Co(CO)(,2)(' )and Cp(CO)Ru((mu)-CO)((mu)-C(SCH(,3))(,2)Co(CO)(,2). Similar reactions were found to occur using the anion PPN Fe- (CO)(,3)NO , except in the case of Ru, yielding (mu)-dithiomethylene compounds of the same general formulation, including the formation of the metallothiocyclopropane ring. The metal carbonyl anions CpMo(CO)(,3)('-), CpFe(CO)(,2)('-), CpRu(CO)(,2)('-), Mn(CO)(,5)('-), and Mn(CO)(,2)-(NO)(,2)('-) did not form (mu)-dithiomethylene compounds in reactions with cationic terminal dithiocarbene complexes. The (mu)-dithiomethylene compounds were found to react with PEt(,3) via loss of a CO ligand. In a reaction previously unreported for (mu)-methylene compounds the (mu)-dithiomethylene compounds reported herein were found to react with a variety of oxidizing agents (I(,2), Br(,2), Ph(,3)C('+), Cp(,2)Fe('+), and C(,7)H(,7)('+)), via a two electron oxidation to yield mononuclear cationic dithiocarbene complexes;Part II of this dissertation describes attempts to synthesize the thiocarbyne compound Cp(CO)Fe(TBOND)CSCH(,3) by deprotonation of the (eta)('2)-carbene compound Cp(CO)Fe (eta)('2)-CHSCH(,3) ('+). The (eta)('2)-carbene is obtained from the acid induced cleavage of a mercaptide group from the cyclic dithioketal(' )Cp(CO)Fe C(SCH(,3))(SCH(,3))H , which is the product of the photolysis of the dithioketal Cp(CO)(,2)Fe C(SCH(,3))(,2)H in hexane. Reactions of the (eta)('2)-carbene with the bases NaH, K(,2)CO(,3), ('-)OR (R = CH(,3), t-butyl), NMe(,3), or proton sponge failed to yield Cp(CO)Fe(TBOND)CSCH(,3). Reaction of the (eta)('2)-carbene with ('-)SCH(,3) in the;presence of CS(,2) lead to the formation of the previously known trithiocarbonate complex Cp(CO)Fe S(,2)C(SCH(,3)) in 49% yield; ('1)DOE Report IS-T-1131. This work was performed under contract no. W-7405-Eng-82 with the U.S. Department of Energy.</p>