Synthesis And Property Studies Of Polyaurated Aryl Complexes

As a kind of important reagent,? organometallic complexes have been extensively used in organic synthesis.They can be used as an organic reactant in various reactions,such as Grignard and organolithium reagents.Furthermore,in the metal-catalyzed organic reactions,they frequently served as an important intermediate.Therefore,detailed structure and reactivity studies of ? organometallic complexes would help us understand the mechanisms of metal-catalyzed organic reactions and meanwhile provide the basis for the discovery of new reactions.In addition,previous studies on the ? organometallic complexes have discovered plentiful physical properties,especially the excellent photophysical properties of heavy metal-substituted aromatic complexes.Therefore,we attempt to develop a viable synthetic method for the efficient synthesis of new ? organometallic aromatic compounds and investigate their reactivity and physical properties.This thesis mainly includes the following parts:(1)We synthesized a Au(I)-activated ethynyl-containing complex by the reaction of 2-ethynylaniline with PPh3 AuCl.This s-aurated complex reacted with the trinuclear gold-oxo complex [(PPh3Au)3(m3-O)](BF4)([Au3O])[Au3O] to undergo an nucleophilic attack on the Au(I)-activated ethynyl and finally generate a tetra-aurated indole complex 2.Furthermore,the reaction of the 2,5-bis((trimethylsilyl)ethynyl)benzene-1,4-diamine with [Au3O] produced a ditopic ?3-imido trinuclear gold(I)complex 9,which reacted with Ph3 PAuCl to generate an octa-aurated benzodipyrrole complex 10.Our mechanistic study revealed that the s-activation of the ethynyl group is necessary for the cyclization transformation.(2)In view of the heavy atom effect of gold,the photophysical properties of four newly synthesized polyaurated compounds have been systematically investigated.The long emission lifetimes in microsecond range together with the oxygen-quenching of the emission and the large Stokes shifts indicate a phosphorescence mechanism from a triplet-excited state for the polyaurated complexes.(3)By using TD-DFT calculation,we studied the aromaticity of the polyaurated five-membered ring.The PPh3 ligands in 2 and 10 was replaced by the PH3 ligands and the aromaticity investigation was conduced at the TPSS/6-31G(d)level.The calculation showed that the NICS(1)zz values of five-membered ring in 2 and 10 are-16.6 and-14.2 ppm,respectively,suggesting the existence of an aromatic ring.This study firstly extends the concept of hyperconjugative aromaticity to transition metal-substituted heterocycles.