Design, Synthesis, Photophysical And Langmuir-Blodgett Film Formation Studies Of Luminescent Amphiphilic Platinum(ii) Complexes

The third row transition metal platinum lies in Group 10 of the periodic table, and its most common oxidation state is +2 with d8 electronic configuration. Platinum(II) complexes usually adopt square planar geometry and they often exhibit intriguing spectroscopic and photophysical properties associated with the occurrence of Pt···Pt andπ?πinteractions. By the effect of the coordination of the stronglyσ-donating alkynyl ligand, the non-radiative deactivation via the d?d LF state can be reduced as a result of a larger d–d LF splitting. Thus, platinum(II) complexes with long lifetime and high quantum yield can be obtained. Polyoxometalates (POMs) exhibit abundant chemical composition, various topologies and extensive physical and chemical properties. Amphiphilic molecules possess special advantages for directing the supramolecular self-assembly of POMs, exhibiting considerable flexibility. In this dissertation, new classes of amphiphilic platinum(II) complexes have been designed and synthesized. In addition to their spectroscopic and luminescence properties, their Langmuir-Blodgett films and surfactant-encapsulated polyoxometalates (SEPs) have also been studied.Two series of novel platinum(II) 2,6-bis(1-alkyl-pyrazol-3-yl)pyridyl (N5Cn) complexes, [Pt(N5Cn)Cl]X (1?9) and [Pt(N5Cn)(C≡CR)]X (10?13) (X = OTf or PF6; R = C6H5, C6H4-CF3?p and C6H4-N(C6H5)2?p), with various chain length of alkyl groups on the nitrogen atom of pyrazolyl units have been successfully synthesized and characterized. Their electrochemical and photophysical properties have been studied. Some of their molecular structures have also been determined by X-ray crystallography. Two amphiphilic platinum(II) 2,6-bis(1-tetradecyl- pyrazol-3-yl)pyridyl (N5C14) complexes, [Pt(N5C14)Cl]PF6 (7) and [Pt(N5C14)(C≡CC6H5)]PF6 (13), were found to form stable and reproducible Langmuir films at the air-water interface. The characterization of such multilayer LB films has been investigated by the study of their surface pressure-area (π–A) isotherms, UV-vis spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT-IR) and polarized IR spectroscopy. The luminescence property of 13 in Langmuir-Blodgett (LB) films has also been studied.Two series of novel platinum(II) 2,6-bis(1-alkyl-1,2,3-triazol-4-yl)pyridyl (N7R) complexes, [Pt(N7R)Cl]X (1?7) and [Pt(N7R)(C≡CR′)]X (8?13) (X = OTf or PF6; R = CnH2n+1, C6H5, CH2C6H5; R′= C6H5, C6H4-CF3?p, C6H4-CF3?p, C6H4-N(CH3)2?p), with various alkyl groups on the nitrogen atom of triazolyl units have been successfully synthesized and characterized. Their electrochemical and photophysical properties have been studied. Two amphiphilic platinum(II) 2,6-bis(1-dodecyl-1,2,3-triazol-4-yl)pyridyl (N7C12) complexes, [Pt(N7C12)Cl]Cl (3-Cl) and [Pt(N7C12)(C≡CC6H5)]Cl (13), were found to form stable and reproducible Langmuir films at the air-water interface. The characterization of such multilayer LB films has been investigated by the study of their surface pressure-area (π–A) isotherms, UV-vis spectroscopy, X-ray diffraction (XRD), Fourier transform infrared (FT-IR) and polarized IR spectroscopy. The luminescence property of 13 in Langmuir-Blodgett (LB) films has also been studied.A series of novel platinum(II)(diimine)(acetylacetonate) ([Pt(bpy)(R-acac)]) complexes, [Pt(bpy)(R-acac)]X (1, 2) (X = OTf or PF6; R = CnH2n+1 or H), with various alkyl groups on the acac units has been successfully synthesized and characterized. Their photophysical properties have been studied. An amphiphilic platinum(II) complex, [Pt(bpy)(C12-acac)]PF6 (2) was found to form stable and reproducible Langmuir films at the air-water interface. The characterization of such multilayer LB films has been investigated by the study of their surface pressure-area (π–A) isotherms, UV-vis spectroscopy, X-ray diffraction (XRD). The luminescence property of 2 in Langmuir-Blodgett (LB) films has also been studied.Two SEPs of platinum(II) complexes ([Pt(N5C14)Cl]OTf and [Pt(N7C12)Cl]OTf) encapsulated Keggin type polyoxometalates (H3PW12O40 and K9BW11O39) (SEP1 and SEP2, respectively) have been successfully synthesized and characterized. The surface pressure-area (π–A) isotherm of SEP2 has also been investigated.