Design, Syntheses And Properties Of Compounds With New Multiple P-Containing Ligands

The P, N ligands have received much attention not only because of their diversestructural chemistry but also due to their potential applications in catalysis, anticancermedicines and optical materials. Among them, heterocyclic diphosphine ligands such asPNP and PCP type compounds have attracted many interests of chemists in recent yearsfor their variable coordination modes, unique steric effects and their usages asprecursors of pincer carbenes. The N-heterocyclic diphosphine ligands are usuallyneutral and only several examples are cationic and their coordination chemistry is stillless explored.In this thesis, we selected a flexible phosphine ligand N,N’-bis（diphenylphosphanylmethyl）ethylene diamine （bdppeda） to react with silver perchlorate in thepresence of HCHO or HCOOH and seperated an unexpected cationic binuclear complex1, while the analogous reactions of AgX （X=Cl, Br, I） with bdppeda and HCHO gaverise to three neutral binuclear complexes. These compounds all contain new cationic orneutral2H（4H）-imidazole-based diphosphine ligands, which were in-situ generatedfrom the reactions. Further treatment of1with concentrated acids （HCl and HBr）yielded two partially anion-exchanged products. The products were characterized byelemental analysis, IR and ESI-MS spectra and single-crystal X-ray crystallography. Weproposed the possible mechanism of the reactions and investigated the contributions ofthe structures of products to their photoluminescent properties. The in-situ formation ofbdppdhi （N,N’-bis （diphenylphosphanylmethyl）-3H-4,5-dihydroimida-zole-1-ium） and bdppthi （N,N’-bis （diphenylphosphanylmethyl）-tetrahydroimidazole） ligands provides a new route to the synthesis of N-heterocyclicdiphosphine ligands, and an insight into the coordination chemistry of their metalcomplexes. This dissertation mainly focused on:（1） Review of the syntheses, structures, and homogeneous catalytic properties of heterocyclic diphosphine ligands.（2） Treatment of bdppeda with Ag（MeCN）4ClO4in the presence of HCHO orHCOOH afforded an cationic binuclear complex [Ag₂（bdppdhi）₂（η,η-μ-ClO₄）₂]（ClO₄）₂·CH₂Cl₂·H₂O （1·CH₂Cl₂·H₂O）. Treatment of1with concentrated HCl and HBrafforded two partial anion-exchanged products [Ag₂（bdppdhi）2（μ-Cl）2]（ClO₄）₂·2CH₂Cl₂·2H₂O （2·2CH₂Cl₂·2H₂O） and [Ag₂（dppeda）Br]（ClO₄）·2MeOH （dppedais N,N,N’,N’-tetra（diphenylphosphanylmethyl）ethylenediamine）（3·2MeOH）. Thecationic bdppdhi ligand might be formed by the Ag+-assisted cyclization reactionsbetween bdppeda and HCHO or HCOOH. These compounds were characterized byelemental analysis, IR and single-crystal X-ray crystallography. Compound1hold acationic bicyclic structure in which a [Ag₂（η,η-μ-ClO₄）₂] ring was bicapped by twobdppdhi ligands. The structure of compound2is similar to that of compound1exceptfor the [Ag₂（μ-Cl）₂] ring. The cation of3shows an interesting molecular basketframework in which dppeda adopted a side-by-side coordination mode. The solutionbehaviors of some compounds were studied by electrospray ionization （ESI） massspectra and the photoluminescent properties of some compounds were also investigated.（3） Reactions of AgX （X=Cl, Br, I） with bdppeda and HCHO gave rise to threeneutral complexes [Ag2（bdppthi）₂（μ-Cl）₂]·2MeOH （4·2MeOH），[Ag₂（bdppthi）2（μ-Br）2]（5） and [Ag₂（bdppthi）₂（μ-I）₂]·2MeOH （6·2MeOH）, in which a neutral N-heterocyclicligand bdppthi was in-situ generated from the cyclization reaction between bdppeda andHCHO in the presence of Ag+. Compounds4⁶hold a neutral bicyclic structure inwhich a [Ag₂（μ-X）₂] ring is bicapped by two bdppthi ligands. Compound4contains1Dchains formed by the weak C–H… Cl hydrogen bonds. These compounds werecharacterized by elemental analysis, IR spectra and single-crystal X-ray crystallography.The solution behaviors of some compounds were studied by electrospray ionization（ESI） mass spectra and the photoluminescent properties of some compounds were alsoinvestigated.