Hydroboration and reductive amination of ketones and aldehydes with HBpin by a bench stable Pd(II)-catalyst.

A palladium(II) complex [(κ4-{1,2-C6H4(NCH-C6H4O)2}Pd] (1) supported by a dianionic salen ligand [1,2-C6H4(NCH-C6H4O)2]2- (L) was synthesised and used as a molecular pre-catalyst in the hydroboration of aldehydes and ketones. The molecular structure of Pd(II) complex 1 was established by single-crystal X-ray diffraction analysis. Complex 1 was tested as a competent pre-catalyst in the hydroboration of aldehydes and ketones with pinacolborane (HBpin) to produce corresponding boronate esters in excellent yields at ambient temperature under solvent-free conditions. Further, the complex 1 proved to be a competent catalyst in the reductive amination of aldehydes with HBpin and primary amines under mild and solvent-free conditions to afford a high yield (up to 97%) of corresponding secondary amines. Both protocols provided high conversion, superior selectivity and broad substrate scope, from electron-withdrawing to electron-donating and heterocyclic substitutions. A computational study based on density functional theory (DFT) revealed a reaction mechanism for Pd-catalysed hydroboration of carbonyl species in the presence of HBpin. The protocols also uncovered the dual role of HBpin in achieving the hydroboration reaction.

Hybrid Lead Bromide Perovskite Single Crystals Coupled with a Zinc(II) Complex for White Light Emission.

Herein we report the fabrication of green emitting hybrid lead bromide perovskite single crystals (HLBPSCs), their anion exchange mediated tunable yellow luminescence and thereby their coupling ability with blue emitting inorganic complex leading to generation of a photostable white light emission, with properties close to bright day sunlight. The partial anion exchange reaction to green emitting HLBPSCs led to formation of yellow emitting anion exchanged HLBPSCs─which are termed as AE-HLBPSCs herein. Then, AE-HLBPSCs were chemically combined with blue emitting Zn-aspirin complex to produce white light with a photoluminescence quantum yield (PLQY) of 47.7%. The solid form of the white light emitting (WLE) composite (followed by coating with poly methyl methacrylate─PMMA) showed color coordinates of (0.34, 0.33), color rendering index of 76 and correlated color temperature of 5282 K. Furthermore, the PMMA coated inorganic complex coupled AE-HLBPSCs showed the preservation of their WLE nature and luminescence stability in their solid form.

De novo synthesis of hybrid d-f block metal complex salts for electronic charge transport applications.

The advent of d-d type complex salts for designing smart functional materials with versatile utility inspired us to develop a novel type of M(II)-Ce(IV) complex salts [M(II) = Cu and Zn ions]. In this study, we present for the first time a holistic approach to design and prepare metal complex salts of the novel hybrid d-f block type, [Cu(bpy)2]2[Ce(NO3)6]2 (1), [Cu(phen)2(NO3)]2[Ce(NO3)6](HNO3) (2), [Zn(bpy)2(NO3)][ClO4] (3), and [Zn(phen)2(NO3)]2 [Ce(NO3)6] (4); [bpy = 2,2'-bipyridine; phen = 1,10-phenanthroline]. The intrinsic structural and morphological properties of the compounds have been revealed by employing a suite of analytical and spectroscopic methods. X-ray structural analysis reveals that the copper(II) centres in the cationic complex units of 1 and 2 adopt a highly distorted tetrahedral and a rare bicapped square pyramidal coordination geometry, respectively. The zinc(II) ions in both 3 and 4 adopt the rare bicapped square pyramidal geometry while the cerium(IV) ions in 1, 2 and 4 exist in a dodecahedral geometry. Investigation of supramolecular interactions reveals that intermolecular O⋯H and O⋯π short contacts bind the complex units in 1, while predominant π⋯π interactions, along with O⋯H and O⋯π short contacts, produce the binding force among the complex units in 2. We further employed the complex salts (1-4) to construct Schottky devices to reveal the role of these new complex salts in the charge-transport phenomenon. The carrier mobilities (µ) for salts 1-4 were determined to be 1.76 × 10-6, 9.02 × 10-6, 1.86 × 10-8, and 4.31 × 10-8 m2 V-1 s-1, with respective transit times (τ) of 439, 85, 4.17 × 103, and 1.79 × 103 ns, which suggest that complex salt 2 is the best candidate with the highest transport properties among all the complex salts. A crystal engineering perspective sheds light on the charge-transport properties of the complex salts, emphasizing the attribution of the best performance of 2 to its predominant π⋯π interactions. The synthesis of this new type of complex salts, their physicochemical properties and their charge-transport applications envisage great promise for the development of novel crystalline materials with smart functionalities.