'Click'-Derived 1,2,3-Triazolium Salts Featuring a 4-Halo-phenyl Group: Precursors for Heterobimetallic Complexes.

The 'click'-derived 1,2,3-triazolium salts [L1/L2-H]I (1-(4-iodo/bromo-phenyl)-1H-1,2,3-triazolium salt) featuring two distinct coordination sites, one via oxidative addition and other via classical deprotonation cum metalation, were designed and explored towards the synthesis of various mono- and bimetallic complexes. Accordingly, a series of well-characterized 1,2,3-triazol-5-ylidene coordinated cyclometalated transition metal complexes (1-3) were obtained. However, these complexes were found to be ineffective in accessing the desired heterobimetallic complexes.

Towards new coordination modes of 1,2,3-triazolylidene: controlled by the nature of the 1 metalation in a heteroditopic bis-NHC ligand.

An unusual effect of the nature of the first metal coordination of a heteroditopic N-heterocyclic carbene ligand (L2) towards the coordination behavior of 1,2,3-tzNHC is explored. The first metal coordination at the ImNHC site (complexes 3 and 4) was noted to substantially influence the electronics of the 1,2,3-triazolium moiety leading to an unprecedented chemistry of this MIC donor. Along this line, the Rh/Ir-orthometalation in complexes 4 makes the triazolium C-H more downfield shifted than C-H, whereas a reverse trend, although to a lesser extent, is observed in the case of the non-chelated Pd-coordination.

Silver-Catalyzed One-Pot Three-Component Synthesis of α-Aminonitriles and Biologically Relevant α-Amino-phosphonates.

A simple silver salt (AgSbF )-catalyzed aminophosphonylation and Strecker reaction have been developed and successfully applied to a wide range of substrates (>55 substrates). This solvent-, ligand-, and base-free one-pot three-component protocol operates effectively at room temperature to provide diversified α-aminophosphonates and α-aminonitriles, which gave access to the respective α-amino amides. Importantly, the present catalyst system is also capable to produce the rarely reported and biologically relevant aminophosphonates (having anti-leishmanial activity).

Recent Advances in the Syntheses and Catalytic Applications of Homonuclear Ru-, Rh-, and Ir-Complexes of C ^C Cyclometalated Ligands.

In the past few decades, chemistry of cyclometalated species has gained momentum with increased applications in several areas of scientific developments. Cyclometalation reactions result in the formation of stable metallacycles through the generation of metal-carbon covalent bonds by activating the unreactive Csp -H or Csp -H bonds. The extra stability gained by the formation of metallacycles enhances their applicability scopes especially in the area of homogeneous catalysis.

Silver-Catalyzed Hydroboration of C-X (X = C, O, N) Multiple Bonds.

AgSbF was developed as an effective catalyst for the hydroboration of various unsaturated functionalities (nitriles, alkenes, and aldehydes). This atom-economic chemoselective protocol works effectively under low catalyst loading, base- and solvent-free moderate conditions. Importantly, this process shows excellent functional group tolerance and compatibility with structurally and electronically diverse substrates (>50 examples).