Synthesis of tetrahydropyrimidine carbene precursors and properties

N-heterocyclic carbenes (NHC) have been an universal ligand on organometallic, inorganic and coordination chemistry. Carben centre has stability due to σ-electron donation and π-electron drawing character supplied by nitrogen centre. Thus N-heterocyclic carbenes are electron rich nucleophilic species. In comparison, N-heterocyclic carbenes showed better bonding than the classical phosphine ligands due to their strong -donating and weak -accepting abilities. The complexes formed between NHC ligands and transition metals more stable than the corresponding analogues phosphine complexes because of the role of the bonding ability of M-NHC. Through selectivity on coordination chemistry of NHCs, they have used many fields of catalytic processes on organic synthesis. Since synthesis and application of pyrimidine derivatives of NHC have been studied very little, we have chosen monodentate pyrimidine carbene precursors. Therefore NHC complexes with transition metals have been prepared and tested for reduction on ketones and arylation reaction of heteroaromatic species. This work could be summarized in eight chapters; 1) In the first chapter, 1,3-dialkyl-1,3,4,5-tetrahydropyrimidinium NHC precursors (2a-o and 3a-l) were synthesized and their structure were elucidated by spectroscopic techniques. 2) Electron rich olefin, obtained by the interaction of a monodentate tetrahydropydimidinium carbene precursors and a base, reacted with S8 ve Se compounds, the corresponding chalcogen derivitavies, 5a-b and 6a-c, were prepared and their structure was elucidated by spectroscopic techniques.. 3) Electron rich olefin, obtained by the interaction of a monodentate tetrahydropydimidinium carbene precursors and a base, reacted with [PdCl2(PPh3)]2, the corresponding Pd-NHC complexes, 7a-d, were prepared and their structure was elucidated by spectroscopic techniques. 4) Electron rich olefin, obtained by the interaction of a monodentate tetrahydropydimidinium carbene precursors and a base, reacted with [IrCl(COD)]2, the corresponding Ir-NHC complexes, 8a-d, were prepared and their structure was elucidated by spectroscopic techniques. 5) Tetrahydropydimidinium carbene precursors reacted with [RuCl2(p-simen)]2, the corresponding tetrahydropydimidinium ruthenium complexes, 9a-9g, were prepared and their structure was elucidated by spectroscopic techniques. 6) Tetrahydropydimidinium carbene precursors reacted with Pd(OAc)2, the corresponding tetrahydropydimidinium palladium complexes, 10a-10e, were prepared and their structure was elucidated by spectroscopic techniques. 7) Ru-NHCcomplexes, formed in situ conditions from tetrahydropydimidinium carbene precursors with [RuCl2(p-simen)]2, and ionic Ru complexes have been tested reduction of ketones and catalytic activities were investigated. 8) Pd-NHC complexes, 7a-7d, and tetrahydropyrimidine Pd complexes, 10a-10e, have been tested on arylation reaction of heteroaromatic species and catalytic activities were investigated.