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Novel lead and bismuth dipyrido complexes have been synthesized and characterized by single-crystal X-ray diffraction, which shows their structures to be directed by highly oriented π-stacking of planar fully conjugated organic ligands. Optical band gaps are influenced by the identity of both the organic and inorganic component. Density functional theory calculations show optical excitation leads to exciton separation between inorganic and organic components. Using UV-vis, photoluminescence, and X-ray photoemission spectroscopies, we have determined the materials' frontier energy levels and show their suitability for photovoltaic device fabrication by use of electron- and hole-transport materials such as TiO2 and spiro-OMeTAD respectively. Such organic/inorganic hybrid materials promise greater electronic tunability than the inflexible methylammonium lead iodide structure through variation of both the metal and organic components. [ABSTRACT FROM AUTHOR]

The molecular structures of the vapors produced on heating dimethylalkoxygallanes of the type [Me2Ga(OR)]2 have been determined by gas electron diffraction and ab initio molecular orbital calculations. In the solid state [Me2Ga(OCH2CH2NMe2)]2 (1) and [Me2Ga(OCH2CH2OMe)]2 (2) adopt dimeric structures, although only the monomeric forms [Me2Ga(OCH2CH2NMe2)] (1a) and [Me2Ga(OCH2CH2OMe)] (2a) were observed in the gas phase. For comparison the structure of the vapor produced on heating [Me2Ga(OtBu)]2 (3) was also studied by gas electron diffraction. In contrast to 1 and 2, compound 3 is dimeric in the gas phase, as well as in the solid state. The gas-phase structures of 1a and 2a exhibit five-membered rings formed by a dative bond between Ga and the donor atom (N or O) from the donor-functionalized alkoxide. In 3 there is no possibility of a monomeric structure being stabilized by the formation of such a dative bond since only a monofunctional alkoxide is present in the molecule. [ABSTRACT FROM AUTHOR]