Synthesis And Reactivity Of Ruthenium-Germanium And Osmium-Germanium Bimetallic Complexes

Heterobimetallic transition metal-germanium complexes,including transition metal germyl,germylene and germylyne complexes which formally possess a metal-germanium single,double and triple bond,respectively,are the group 14 heavy congers of the well-studied corresponding transition metal alkyl,carbene,and carbyne complexes.This family of complexes has attracted considerable fundamental interest on structure,bonding and reactivity especially given the curiosities of such complexes,which are expected to exhibit new and interesting reactivity patterns.Impressive progress has been made in the past decades on the chemistry of early transition metal-germanium complexes.However,the parallel research along this line for late transition metal is still much less developed.In this dissertation,we have studied the reactions of ruthenium and osmium complexes with the three-coordinate germylene LGeX(L = CH[C(Me)N-2,6-iPr2C6H3]2;X = Cl,C?CPh,C?CFc)and the two-coordinate germylene RGeCl(R = 2,6-Trip2C6H3;Trip = 2,4,6-iPr3C6H2),respectively.A series of ruthenium germyleme complexes featuring the germylenes as donor ligands as well as the bimetallic complexes with M-Ge(M = Ru,Os)single-bond have been successfully synthesized and their reactivity were also investigated.This disertation consists of the following five parts.In chapter 1,the research progress on the transition metal germyl,germylene and germylyne complexes including the synthetic methods and the reactivity studies are briefly reviewed.Furthermore,the research objectives of this dissertation are also presented.In chapter 2,synthesis and reactivity studies of a series of Ru?Ge type carbonyl ruthenium germylene compounds are described.Reactions of LGeX(L =HC[C(Me)N-2,6-iPr2C6H3]2;X = Cl,C?CPh,C?CFc)with Ru3(CO)12 in a molar ratio of 6:1 led to the Ge2Ru bis-germylene ruthenium compounds[L(Cl)Ge]2Ru(CO)3(2-4),[L(PhC=C)Ge]2Ru(CO)3(2-5)and[L(FcC=C)Ge]2Ru(CO)3(2-6),while the GeRu mono-germylene ruthenium compound[L(PhC=C)Ge]Ru(CO)4(2-7)was solely yielded from the reaction of LGe(C=CPh)with Ru3(CO)12 in the 3:1 molar ratio.Treatment of of 2-4 with H2O and I2 afforded[LGeOH]2RuCl2(CO)3(2-8)and[LGeCl]RuI2(CO)3(2-9),respectively.Reaction of 2-4 with LiHBEt3 occurred by an unusual Cl/Et meathesis to give the ethylated compound[LGeEt]Ru(CO)4(2-10).The reaction of 2-4 with LiN(SiMe3)2,however,resulted in the base-assisted dehydrochlorination involving one methyl group on each L ligand backbone and the Cl at the Ge center to give[L'Ge]2Ru(CO)3(2-11,L' ?HC[C(Me)N-2,6-iPr2C6H3Ar][C(CH2)N-2,6-iPr2C6H3]).Further reaction of 2-11 with stoichiometric H2O produced[LGeOH]Ru(CO)4(2-12)via a 1,4-dipolar addition across the L'Ge.In chapter 3,synthesis and reactivity of the Ru-Ge single-bonded bimetallic compounds are decribed.Reactions of RGeCl(R = 2,6-Trip2C6H3;Trip ?2,4,6-iPr3C6H2)with RuCl2(PPh3)3 and RuHCl(PPh3)3 produced(PPh3)CIRuGeCl2(Trip)C6H3((?)6-Trip)(3-1)and(PPh3)HRuGeCl2(Trip)C6H3((?)6-Trip)(3-2),respectively.Phosphine ligand substitution reactions of 3-1 with PMe3 or DMSO gave(PMe3)ClRuGeCl2(Trip)C6H3((?)6-Trip)(3-3)and(DMSO)ClRuGeCl2(Trip)C6H3((?)6-Trip)(3-4),respectively.Treatment of 3-1 with Na/C10H8 afforded(PPh3)HRuGe(OH)2(Trip)C6H3((?)6-Trip)(3-8).Reaction of 3-2 with LiHBEt3 yielded the ethylated product(PPh3)HRuGeEt2(Trip)C6H3((?)6-Trip)(3-5),which treatment of EtMgBr at RT produced the bromide complex(PPh3)HRuGeBr2(Trip)C6H3((?)6-Trip)(3-6)first,which could be eventually converted to the ethylated product 3-5 after further reacted with EtMgBr under heating condition.Similarly,reaction of 3-2 with PhCH2MgCl afforded the corresponding benzylated product(PPh3)HRuGe(CH2Ph)2(Trip)C6H3((?)6-Trip)(3-7).Treatment of 3-2 with HBF4 produced the dihydride ruthenium complex[(PPh3)(H)2RuGeCl2(Trip)C6H3((?)6-Trip)]BF4(3-9),which could be readily deprotonated in the presence of H2O to afford 3-2 again.In chapter 4,synthesis and reactivity of the Os-Ge single-bonded bimetallic compounds are described.Reactions of RGeCl(R = 2,6-Trip2C6H3;Trip =2,4,6-iPr3C6H2)with OsCl2(PPh3)3 or OsHCl(PPh3)3 produced the Os-Ge single-bond compounds(PPh3)ClOsGeCl2(Trip)C6H3((?)6-Trip)(4-1)and(PPh3)HOsGeCl2(Trip)C6H3((?)6-Trip)(4-2),as well as the novel Ge-C coupling compound(PPh2C6H4)HOsGeCl(Trip)C6H3((?)6-Trip)(4-3),respectively.The formation 4-3 presumably involved insertion of phenyl C-H into the osmium germylene,which is similar to the carbene C-H insertion.Again,as was the case in the reactions for the Ru-Ge compounds 3-2,treatment of 4-2 with EtMgBr,depending on the reaction conditions,could afford(PPh3)HOsGeBr2(Trip)C6H3((?)6-Trip)(4-6)and(PPh3)HOsGeEt2(Trip)C6H3((?)6-Trip)(4-5),successively.Reaction of 4-2 with HBF4 yielded the dihydride osmium[(PPh3)(H)2OsGeCl2(Trip)C6H3((?)6-Trip)]BF4(4-6),which can be readily deprotonated by H2O to give 4-2.In chapter 5,the research work of dissertation is summarized and the prospect of this research is presented.