Synthesis And Properties Of Reversible Photoluminescent Sensors Based On Au-P-S Complexes

Gold complexes usually have abundant structures and contain variable Au···Au interactions,thus may exhibit diverse photophysical properties.Their photoluminescences and stimuli-response phenomena have attracted much attentions.Phosphine/Sulfur ligands can effectively stabilize the Au（I）complexes and have also been proven to enhance their response performances.In this thesis,we prepared the precursor[（3-bdppmapy）（Au Cl）₂]from a phosphine ligand 3-bdppmapy（N,N-bis-（diphenylphosphonylmethyl）-3-aminopyridine）and Au（tht）Cl（tht=tetrahydrothiophene）.Their assembly with different S donor ligands Na Hmba（sodium 2-mercaptobenzoate）and Na Hmna（sodium 2-mercaptonicotinate）resulted in two tetra-nuclear clusters.Using these clusters as photoluminescence sensors,we studied their reversible responses to thermal and mechanical grinding,respectively.The major topics of this thesis includes:1.The research progress on the photoluminescent（PL）responses of Au-P complexes toward environmental stimuli and the response mechanisms were reviewed.2.The assembly of[（3-bdppmapy）（Au Cl）₂]with Na Hmba resulted in complex[（3-bdppmapy）₂（Au Hmba）₃（Au Cl）]（1）.Compound 1 emitted green fluorescence at 522 nm under 370 nm excitation.The emission intensity increased significantly with the decrease in temperature.The mixture of 1 and the red-emitting phosphor N630 in different proportions showed sensitive and reversible thermotropic photoluminescence behavior over the temperature range of 80–300 K and 300–370 K.The composition of these mixtures with PMMA produced thin film and optical fiber materials that could be used as reusable fluorescent thermometers.3.The assembly of[（3-bdppmapy）（Au Cl）₂]with Na Hmna yielded complex[（3-bdppmapy）₂（Au Hmna）₂（Au Cl）₂]（2）.Compound 2 emitted bright yellow fluorescence at 546nm under 377 nm excitation.When 2 was ground in a mortar,its photoluminescence intensity decreased significantly and rapidly,which could be recovered by exposing it to CH₂Cl₂ vapor.Further studies indicated the mechanism of this reversible fluorescence on/off conversion was not influenced by static pressure and temperature,but more likely due to the shifting of the packing mode of the molecules that was caused by the grinding.