Study On The Synthesis,Structure And Properties Of Organic Photochromic Compounds

In this paper, three kinds of novel organic photochromic compounds containing pyrazolone-ring have been synthesized and characterized. Their photochromic properties have been studied by their crystal structure analyses. The relation between the structure and V properties has been obtained. The paper consists of five parts. In the first part, two new photochromic compounds, (I?-phenyl-3?-methyl-4?- benzoformyl-pyrazolone-5?)-4-methyl-thiosemicarbazone (PMBP-MTSC) and (I?-phenyl- 3?梞ethyl-4?-benzoformyl-pyrazolone-5?)-4-phenyl-thiosemicarbazone (PMBP-PTSC), have been synthesized and characterized by elemental analyses, MS, UV spectra, single- crystal XRD. The photochromic properties and photochemical kinetics of PMBP-MTSC have been studied by powder 桿V reflectance spectra under irradiation of 365nrn light. The crystal structure of colorless product of PMBP-MTSC shows the photochromism is due to the photoisomerization from keto form to enol form. According to the results of structure analyses. an intermolecular proton transfer mechanism of the photochromism is proposed. In the second part, the complex [Co (PMBP-TSC) 2?DMF?H20] has been synthesized and the structure has been determined by X-ray crystallography. 2~ is six coordinated with a distorted octahedral coordination sphere. The studies of crystal structure indicate that the water molecules bridge the molecules of the adjacent stacks through hydrogen bonds, which leads to the supramolecular of three-dimension network structure. Moreover, the reason of the complex without photochromic properties has been analyzed. In the third part, derivants of hydrazide photochromic compounds containing pyrazolone have been synthesized and characterized by elemental analyses, IR spectra, 慔NMR, single- crystal XRD. The structure of two compounds, the photochromic N-( I -phenyl-3-methyl-4- benzoformyl-pyrazolone-5 )-picolinlyhydrazide (PMBP-PCH) and non-photochromic N-( I - phenyl-3-methyl-4-benzoformyl-pyrazolone-5)- nicotinoylhydrazide (PMBP-NTH) have been studied. The results show H-transfer phototautomerism from enol form to cis-keto form occurs in PMBP-PCH. In the fourth part, N- (1-phenyl-3-methyl-4-benzoforinyl-pyrazolone-5)-p-anisic hydrazide (PMBP-PAH) and its complexes have been synthesized and characterized by V elemental analyses, JR spectra, UV spectra, X-ray ciystallography. These studies of the non- photochromic compounds confirm hypothesis in the third part. In the fifth part, a novel photochromic heterocyclic compound (PMCP-TSC) has been synthesized and characterized by elemental analyses, MS. UV spectra, IR spectra, 慔 NMR, single-crystal XRD. The photochromic properties have been studied by UV spectra under irradiation of 365nrn light. First-order rate constant of the photochemical reaction was calculated. The crystal structure shows the photochromism is due to the photoisomerization from enol form to keto form. An intramolecular proton transfer mechanism of the photochromism is proposed.