Research Projects

The current proposal builds upon our group’s recent preliminary experimental work on the synthesis and isolation of terpyridine-based bis(phosphine) and tris(phosphine) pincer ligand frameworks. We have obtained promising initial data supporting the formation of [{N₃P₂}GePdXₙ] complexes, demonstrating the feasibility of stabilizing metal–main group element bonds within these ligand architectures. Additionally, the successful synthesis of the PPP-platform is supported by the ³¹P NMR spectral data, confirming the formation of the tris(phosphine) framework. These preliminary findings provide a strong foundation for the proposed systematic study of such ligands and their coordination behaviour with main group and transition metals. Stereo-electronically tuned ligands play a vital role in the stabilization and isolation of unusual main-group organometallic fragments. These low-valent species are not only of fundamental interest but also hold significant potential in homogeneous catalysis. The proposed work focuses on terpyridine-based bis(phosphine) and tris(phosphine) ligands of the type N₃P₂ and PPP- (where atoms represent donor centers), which can serve as excellent platforms for stabilizing unusual metal–main group element (M–E) bonds. The pincer framework of these ligands effectively supports the formation and isolation of diverse transition metal–main group element complexes, particularly involving group 13 (B, Ga, In) and group 14 (Ge, Sn) elements. By employing such ligands, it is possible to stabilize uncommon bonding environments and access solid-state structures that exhibit novel and previously unobserved bonding scenarios. These systems can demonstrate cooperative interactions between the metal and the main group element. Moreover, halogen-substituted M–E bonds can be accessed, and subsequent reduction reactions of such M–EXₙ species may lead to the formation of multiple bonded systems. The proposed work explores the terpyridine framework as a platform for the installation of cationic P(III) centers and overall neutral P(III)–P(I)–P(III) species. If successfully synthesized, these mixed-valent phosphorus donor ligands could open new avenues for coordination to various Lewis-acidic systems. Although their isolation is synthetically challenging, it is considered achievable through a systematic and controlled approach. The bis(phosphine) N₃P₂ systems remain relatively underexplored and are still in their infancy, leaving ample room for the development of novel synthetic strategies. Utilizing such frameworks, it is possible to access a variety of homo- and heterobimetallic complexes incorporating both transition metals and main-group elements. Proposed complexes of the general formula [{N₃P₂}PdM] (where M = main-group metal) could serve as potential single-source molecular pre-catalysts for various organic transformations. Furthermore, the P(III)–P(I)–P(III) species may demonstrate promising reactivity in small molecule activation, such as toward CO₂, and their performance can be benchmarked against existing systems. The research will involve extensive experimental work, conducted under inert atmosphere using Schlenk line techniques. A series of reactions will be performed using group 13 and group 14 element halides in combination with late transition metals such as Ru and Pd, aiming to isolate novel and structurally intriguing organometallic species. In recent times, one paper appeared about the utility of carbenes-supported phosphinidines of the type (NHC)PR in metal-free CO2 reduction and conversion reactions. One can anticipate that the metal-free complexes of type [{N₃P₂}PR]CE₂ (E = O, S) can be isolable, and will be examined their utility as metal-free catalysts for CO₂ reduction and conversion reactions., for instance in the hydrosilylation of CO2, and N-formylation of primary (NRH₂), and secondary amines (NR₂H) under CO₂ atmospheric conditions.