Facile one pot synthesis of highly photoresponsive coinage metal selenides (Cu1.8Se and Ag2Se) achieved through novel Cu and Ag pyridylselenolates as molecular precursors

Copper selenide (Cu_1.8Se) and silver selenide (Ag₂Se) have garnered unprecedented attention as efficient absorber materials for cost-effective and sustainable solar cells. Phase pure preparation of these exotic materials in a nano-regime is highly desirable. This account outlines a simple and easily scalable pathway to Cu_1.8Se and Ag₂Se nanocrystals using novel complexes [Cu{2-SeC₅H₂(Me-4,6)₂N}]₄ (1), [Ag{2-SeC₅H₂(Me-4,6)₂N}]₆ (2) and [Ag{2-SeC₅H₃(Me-5)N}]₆·2C₆H₅CH₃ (3·2C₆H₅CH₃) as single source molecular precursors (SSPs). Structural studies revealed that the Cu and Ag complexes crystallize into tetrameric and hexameric forms, respectively. This observed structural diversity in the complexes has been rationalized via DFT calculations and attributed to metal-metal bond endorsed energetics. The thermolysis at relatively lower temperature in oleylamine of complex 1 afforded cubic berzelianite Cu_1.8Se and complexes 2 and 3 produced orthorhombic naumannite Ag₂Se nanocrystals. The low temperature synthesis of these nanocrystals seems to be driven by the observed preformed Cu₄Se₄ and Ag₆Se₆ core in the complexes which have close resemblance with the bulk structure of the final materials (Cu_1.8Se and Ag₂Se). The crystal structure, phase purity, morphology, elemental composition and band gap of these nanocrystals were determined from pXRD, electron microscopy (SEM and TEM), EDS and DRS-UV, respectively. The band gap of these nanocrystals lies in the range suitable for solar cell applications. Finally, these nanocrystal-based prototype photo-electrochemical cells exhibit high photoresponsivity and stability under alternating light and dark conditions.

Diorganyl diselenides: a powerful tool for the construction of selenium containing scaffolds

Organoselenium compounds find versatile applications in organic synthesis, materials synthesis, and ligand chemistry. Organoselenium heterocycles are widely studied agents with diverse applications in various biological processes. This review highlights the recent progress in the synthesis of selenium heterocycles using diorganyl diselenides with keen attention on green synthetic approaches, scopes, C-H selanylation, the mechanisms of different reactions and insights into the formation of metal complexes. The C-H selanylation using diorganyl diselenides with different catalysts, bases, transition metals, iodine salts, NIS, hypervalent iodine, and other reagents is summarised. Finally, the diverse binding modes of bis(2/4-pyridyl)diselenide with different metal complexes are also summarised.

Application of 4-pyridylselenolate palladium macrocycles in Suzuki couplings

Pd macrocycles of diphosphine were constructed employing 4-pyridylselenolate. They act as excellent catalysts in the Suzuki coupling reaction.

Internally functionalized multifaceted organochalcogen compounds

Internally functionalized multifaceted organochalcogen compounds have been designed and their ligand chemistry has been developed. The palladium complexes show remarkable homogeneous catalytic activity.

Applications of metal selenium/tellurium compounds in materials science

Metal chalcogenides are technologically important materials. Physical, chemical, electrical and mechanical properties of these materials can be fine-tuned by manipulating their shape, size and composition. Although several methods are employed for their synthesis, single-source molecular precursor route has emerged as a versatile strategy for their synthesis and in controlling shape, size and composition of the material under moderate conditions. This chapter gives a brief coverage on the design and development of single-source molecular precursors which have been employed for the preparation of metal selenide/telluride nanocrystals and for deposition of thin films. The discussion includes synthesis of transition-, main group and f-block metal chalcogenolate and/or chalcogenide clusters as precursors and their conversion into metal chalcogenides in the form of thin films and nanostructures. Precursors for ternary metal chalcogenides are also included.

Synthesis and structure of [(Ph3P)2Cu(μ-SeCH2Ph)2In(SeCH2Ph)2] as a single-source precursor for the preparation of CuInSe2 nano-materials

The reaction of freshly prepared Na[In(SeCH₂C₆H₅)₄] with the mixture of CuCl and triphenylphosphine in methanol yielded [(PPh₃)₂CuIn(SeCH₂C₆H₅)₄]. The X-ray structure of the complex revealed the monomeric form of [(Ph₃P)₂Cu(μ-SeCH₂Ph)₂In(SeCH₂Ph)₂] consisting of tetrahedral Cu(i) and In(iii) centers, bridged by two benzyl selenolate ligands. The complex on pyrolysis in a furnace or in oleylamine/HDA yielded tetragonal CuInSe₂. The morphology and composition of nanostructures were investigated by pXRD, SEM, TEM and EDX analysis. The band gap of the CuInSe₂ nanostructures, obtained from pyrolysis in HDA and OA has been deduced from DRS as 1.85 and 1.86 eV, respectively.

The complex [(Ph₃P)₂Cu(μ-SeCH₂Ph)₂In(SeCH₂Ph)₂] has been synthesized and structurally characterized, which on solvolysis yielded single phasic CuInSe₂ nanoparticles. The particles were characterized by pXRD, SEM, HRTEM, EDX and DRS analysis.

New binding modes for CSe: coinage metal coordination to a tungsten selenocarbonyl complex

The reaction of the new tungsten selenocarbonylate [Et₄N][W(CSe)(CO)₂(Tp*)] (Tp* = hydrotris(dimethyl-pyrazolyl)borate) with coinage metal based electrophiles provides access to a range of new bridging modes for the selenocarbonyl ligand.

Pyridyl and pyrimidyl chalcogenolates of coinage metals and their utility as molecular precursors for the preparation of metal chalcogenides

Synthesis of and metallophilic interactions in N-heterocyclic chalcogenolates of coinage metals have been described and their utility as molecular precursors for binary and ternary chalcogenide materials has been demonstrated.

Diverse silver(i) coordination chemistry with cyclic selenourea ligands

The reactions of cyclic selenoureas with silver(i) salts yield new coordination complexes with sterically-controlled solid state aggregation.