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- Metal–organic ligands with mixed chalcogenides are potential compounds for the preparation of mixed anionic metal chalcogenide alloys. However, only a few of such ligands are known, and their complexes are not well explored. We have prepared homo- and hetero-dichalcogenoimidodiphosphinate [(EE′PiPr2NH)] (E, E′ = Se, Se; S, S; S, Se) complexes of manganese and copper through metathetical reactions. The X-ray single crystal structure of [Mn{(SePiPr2)2N}2] 1 revealed a triclinic crystal system, with a MnSe4 core unit, whereas the crystal structure determination of [Mn{(SPiPr2)(SePiPr2)N}2] 2 indicated a triclinic crystal system with a Mn(S/Se)2 unit. Both metal centres are tetrahedral, with two deprotonated bidentate ligands forming the coordination sphere. The free ligand was found to exhibit a gauche configuration in the solid state. The energies of the various rotamers of dithio-analogue were studied by DFT calculations. The decomposition behaviour of complexes with homo- and heterochalcogenides was investigated, and the complexes were employed as single-source precursors to generate manganese and copper chalcogenides through solvent-less melt reactions between 500 and 550 °C. The deposited powders were characterized by powder X-ray diffraction (p-XRD), scanning electron microscopy (SEM), energy dispersive analysis of X-ray (EDAX), transmission electron microscopy (TEM), and elemental mapping. MnS, MnSe2, and MnSSe phases were obtained from the decomposition of respective manganese complexes. In contrast, the decomposition of copper-based complexes yielded Cu2–xSe and the sulphur-doped Cu3Se2 phase from seleno- and mixed thio/seleno-complexes of Cu, respectively. The morphology ranged from random sheet-like structures to agglomerated platelets, while the selected area electron diffraction (SAED) revealed the crystalline nature of the materials. Depending on the nature of the complex and the temperature, different amounts of phosphorus were present as an impurity in the synthesized products.
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- A distorted single crystal structure of bis(piperidinedithiocarbamato)lead(II) complex and its subsequent use to deposit thin films is reported. Two deposition routes namely, aerosol-assisted chemical vapour deposition (AACVD) and spin coating deposition have been employed to obtain anisotropic lead sulfide (PbS) nanostructures. The thin films displayed rod to cubic shaped crystals for AACVD, and a range of cubes, star and dendritic morphologies with variation of temperatures were displayed for spin coated films. Optical band gaps between 1.32 and 1.55 eV as controlled by the change in temperature were observed for thin films deposited by AACVD. Powder X-ray diffraction (P-XRD) studies show that the films formed are composed of cubic crystalline PbS. The X-ray photoelectron spectroscopy (XPS) was used to investigate the effect of activation temperatures (350, 400 and 450 °C) on the chemical composition and oxidation states of PbS samples.
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- The development of cost‐effective and easily accessible bifunctional materials, which can be effectively used for energy storage and energy generation, is highly desirable. Herein, a new molecular precursor [tris(morpholinodithiocarbamato)Co(III)] has been synthesized and the X‐ray crystal structure of the complex determined. The precursor was used to prepare oleylamine (OLA)‐capped cobalt sulfide nanoplatelets, using a facile hot injection method at two different temperatures (200 °C and 260 °C). The characterization of the samples shows that CoS synthesized at 200 °C is slightly sulfur rich, whereas CoS synthesized at 260 °C is slightly cobalt rich. The effect of off‐stoichiometry of CoS nanoplatelets on the energy generation and storage applications was studied. The oxygen evolution reaction catalytic performance of both samples indicate overpotentials of 307 and 276 mV as well as Tafel slopes of 96 and 82 mV/dec, respectively. Similarly, overpotentials of 132 and 153 mV were observed for the hydrogen evolution reaction, with Tafel slopes of 159 and 154 mV/dec, respectively. The capacitive behavior of the samples was also examined, and specific capacitance values of 298 and 440 F/g were obtained with cycling stabilities of 73 and 97 %, after 5000 cycles, respectively. The results indicate that sulfur‐deficient CoS can show superior performance for efficient energy generation and storage devices.
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- A series of Fe(III), Co(III), Ni(II), Cu(II), Zn(II) and In(III) N-morpholine-N'-benzoyl thiourea complexes have been synthesized and characterized by elemental analysis, thermal analysis, infrared spectroscopy, 1H nuclear magnetic resonance spectroscopy and single-crystal X-ray crystallography. Thermogravimetric analysis shows that all the complexes undergo a two-step decomposition process except for the iron(III) complex and the indium(III) complexes, which show three-step and one-step decompositions, respectively. The complexes are thermally stable up to approximately 300°C. The ligand coordinates the various metal ions in a bidentate (L-kO,S) chelating mode, facilitated by deprotonation of the acidic amide (–C(O) N'HC (S)) moiety. This mode of coordination allows for the facile formation of neutral bis/tris-6-membered chelates of type [M(L-kS,O)x] where x = 2 or 3 for divalent or trivalent metal ions, respectively.
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