Ueber gasanalytische Methoden und Apparate

Ohne Zusammenfassung     

Luminescent Cyclometalated Alkynylplatinum(II) Complexes with a Tridentate Pyridine‐Based N‐Heterocyclic Carbene Ligand: Synthesis,Characterization, Electrochemistry,Photophysics, and Computational Studies

A new class of luminescent alkynylplatinum(II) complexes with a tridentate pyridine‐based N‐heterocyclic carbene (2,6‐bis(1‐butylimidazol‐2‐ylidenyl)pyridine) ligand, [Pt^II(C^N^C)(C?CR)][PF₆], and their chloroplatinum(II) precursor complex, [Pt^II(C^N^C)Cl][PF₆], have been synthesized and characterized. One of the alkynylplatinum(II) complexes has also been structurally characterized by X‐ray crystallography. The electrochemistry, electronic absorption and luminescence properties of the complexes have been studied. Nanosecond transient absorption (TA) spectroscopy has also been performed to probe the nature of the excited state. The origin of the absorption and emission properties has been supported by computational studies.     

Supramolecular Self-assembly of Amphiphilic Alkynyl-platinum(II) 2,6-Bis(N-alkylbenzimidazol-2'-yl) pyridine Complexes

Alkynylplatinum(II) bzimpy complexes of trimethylammonium-benzylethynyl ligand have been synthesized and characterized. Complexes with long alkyl chains have been found to exhibit interesting self-assembly properties in the acetonitrile solution. The amphiphilic nature of the complexes has led to the formation of nanorods, as revealed by electron microscopy experiments. Further increasing the polarity of the solvent media has given rise to the enhancement of low-energy emission.     

Luminescent metal alkynyls - from simple molecules to molecular rods and materials

This review describes the design and synthesis of a number of luminescent transition metal alkynyls by this laboratory. The luminescence properties of the complexes have been studied and their emission origin elucidated. Some of these complexes have been shown to be ideal building blocks for the design and construction of luminescent molecular rods and materials, in which the luminescence properties can be readily tuned by changing the alkynyl ligands. Some of them also exhibited luminescence switching behaviour with the “ON-OFF” luminescence states modulated by redox processes, metal ion-binding or solvent composition.     

Spectroscopic characterizations of molecularly linked gold nanoparticle assemblies upon thermal treatment

The understanding of surface properties of core-shell type nanoparticles is important for exploiting the unique nanostructured catalytic properties. We report herein findings of a spectroscopic investigation of the thermal treatment of such nanoparticle assemblies. We have studied assemblies of gold nanocrystals of approximately 2 nm core sizes that are capped by alkanethiolate shells and are assembled by covalent or hydrogen-bonding linkages on a substrate as a model system. The structural evolution of the nanoparticle assemblies treated at different temperatures was probed by several spectroscopic techniques, including UV-visible, Fourier transform infrared (FTIR), and X-ray photoelectron spectroscopy (XPS). The results show that the capping/linking shell molecules can be effectively removed to produce controllable surface and optical properties. The data further revealed that the thermally induced evolution of the surface plasmon resonance property of gold nanoparticles is dependent on the chemical nature of the linker molecule. The spectral evolution is discussed in terms of changes in particle size, interparticle distance, and dielectric medium properties, which has important implications for controlled preparation and thermal processing of core-shell nanostructured metal catalysts.     

Molecular Dyads Comprising Metalloporphyrin and Alkynylplatinum(II) Polypyridine Terminal Groups for Use as a Sensitizer in Dye‐Sensitized Solar Cells

A new class of molecular dyads comprising metalloporphyrin‐linked alkynylplatinum(II) polypyridine complexes with carboxylic acids as anchoring groups has been designed and synthesized. These complexes can sensitize nanocrystalline TiO₂ in dye‐sensitized solar cell (DSSC) studies. The photophysical, electrochemical, and luminescence properties of the complexes were studied and their excited‐state properties were investigated by nanosecond transient absorption spectroscopy, with the charge‐separated [Por^.??{(C?C)Pt(tBu₃tpy)}^.+] state observed upon excitation. Excited‐state redox potentials were determined; the electrochemical data supports the capability of the complexes to inject an electron into the conduction band of TiO₂. The complexes sensitize nanocrystalline TiO₂ and exhibited photovoltaic properties, as characterized by current–voltage measurements under illumination of air mass 1.5 G sunlight (100 mWcm^?2). A DSSC based on one of the complexes showed a short‐circuit photocurrent of 10.1 mAcm^?2, an open‐circuit voltage of 0.64 V, and a fill factor of 0.52, giving an overall power conversion efficiency of 3.4 %.     

Luminescent gold(I) complexes for chemosensing

With the rich spectroscopic and luminescence properties associated with aurophilic Au?Au interactions, gold(I) complexes have provided an excellent platform for the design of luminescent chemosensors. This review concentrates on our recent exploration of luminescent gold(I) complexes in host–guest chemistry. Through the judicious design and choice of the functional receptor groups, specific chemosensors for cations and/or anions have been obtained. Utilization of sensing mechanisms based on the on–off switching of Au?Au interactions and photoinduced electron transfer (PET) has been successfully demonstrated. The two-coordinate nature of gold(I) complexes has also been utilized for the design of ditopic receptors through connecting both cation- and anion-binding sites within a single molecule.