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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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- Binary PbS and SnS nanoparticles have dominated materials chemistry research due to their optical and photocatalytic potentials. Hence, in this work, (E)-2-(1-(2-oxo-2h-chromen-3-yl) ethylidene) hydrazinecarbothioamide [H3L3] was prepared by the reaction of an intermediate (3-acetylcoumarin) formed by cycloaddition and cyclocondensation of ethyl acetoacetate and salicyaldehyde with thiosemicarbazide in ethanol. The metal complexes were then successfully synthesised in ethanolic solution of N, N′-dicyclohexyldithiooxamide and [H2L2] with the corresponding Pb(II) and Sn(II) salts. The products obtained were characterized by FT-IR spectroscopy and micro elemental analysis. IR frequencies of the corresponding complexes show significant shifts from the absorption frequencies of the ligand at 1721.31 cm− 1 (C––O), 1671.72 cm− 1 (C––N), 1282.00 cm− 1 (C––S) and 1721.31 (C––O), 1673.30 (C––N), and 1281.30 (C––S) due to coordination to Pb2+ or Sn2+, respectively. Thermogravimetric analysis indicated weight loss of about 60 %, subdivided into two weight loss stages: the first stage occurred in the temperature range 150–300 ◦C, accounting for 42 % loss related to the removal of hydrazinecarbothioamide derivative ligand, while the second occurred between 300 and 400 ◦C, 18% weight loss accounting for the dicyclohexyl derivative. PbS and SnS nanoparticles were equally synthesised from their precursors metal complexes through solvothermal decomposition at 200, 240 and 250 ◦C in oleylamine and dodecanethiol. P-XRD, SEM-EDX, TEM and HRTEM were used to characterise the resulting stable nanoparticles. Pure cubic crystal phase of PbS NPs (galena) with a space group of F m − 3 m and orthorhombic SnS NPs (Herzenbergite) with P b n m space group were obtained. The crystallite sizes varied with temperature, as the average diameter for PbS nanoparticles ranged from 16.34 nm to 19.34 nm, while the particle size varied from 21.30 to 38.00 nm. Similarly, the orthorhombic SnS NPs obtained have crystallite size ranging from 13.15 to 22.91 nm, while the agglomerated nanoparticles measured an average of 52.14 nm at 200 ◦C, and a triangular shape of 498.88 nm was formed at 240 ◦C. The energy bandgaps and optical emission of the PbS and SnS nanocrystals were found to be 2.18 eV (570.98 nm) and 2.32 eV (544.63 nm), respectively. These values are within the optimum range for photovoltaic applications
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