The design and synthesis of polyphosphine ligands with hemilabile functionalities has been an active field of research for many years due to the wide
structural diversity of their metal complexes and unique catalytic properties. This class of ligands can readily form multinuclear complexes and also bring
two metals into close proximity which can enhance the catalytic performance. These rigid polydentate ligands have been widely for the construction of
polynuclear clusters and cages and metal–organic frameworks with desired porosity and functionality for small molecule encapsulation.
Representative publications
The design and study of well-organized metal containing macrocycles or cages has emerged as a promising research area in modern supramolecular chemistry
because of its applications in photovoltaics, therapeutic agents catalysis, and tunable chemical sensors. The most favorite building blocks for the construction
of transition metal based self-assemblies are essentially platinum group metals. Recently, extensive studies are focused on group 11 metal complexes because of
their rich photophysical properties.
Representative publications
Water-soluble ligands and their transition metal complexes are appropriate for biological studies and are preferred in catalytic reactions because of the
easy separation of the organic products from the catalyst. The aqueous/organic biphasic systems require solubilizing the catalyst in water, which can be
achieved by incorporating highly polar functionalities into the ligand framework. However, apart from the sulfonation of arylphosphines, the utility of
other polar groups is less extensive. This may be due to the limitations in choosing the ligand framework and the availability of suitable sites for
the incorporation of such functional groups. This problem can be addressed by choosing an appropriate phosphorus-based ligand framework containing
nitrogen atoms, which on simple addition of alkyl halide can produce a Zwitterion, thus making them soluble in polar solvents. In this context, we
found that cyclodiphosphazanes or diazadiphosphatedines are ideal candidates as both nitrogen and phosphorus atoms can be readily tuned in terms of
both steric and electronic aspects.
Representative publications
Transition metal complexes of phosphorus based ligands have proven to be very useful in several catalytic organic transformations. The donor atoms and
their substituents allow the fine tuning of the steric and electronic properties around metal center. These complexes have been successfully employed in
several C–C bond forming reactions, other catalytic reactions. Furthermore, chiral ligands have been studied with high potential in asymmetric catalytic
reactions.
Representative publications