Organometallics Research Group

Welcome to Prof. Pradeep Mathur's Homepage

Summary of Research Interests

Research interests fall in the general area of Organometallic Chemistry.

Metal mediated transformations of acetylenes                           

           Using simple mononuclear metal carbonyls, some unusual transformation have been observed, including the first example of a structurally characterized pentahapto-coordinated cyclopentadienone ligand system.  In presence of sulfur or selenium, ferrocenyl-substituted thiophene and selenophene derivatives have been prepared under mild conditions. Ferrocenylchalcogenopropargyl complexes have been synthesized and their reactions in metal cluster synthesis has led to isolation of unusual ferrocenyl-containing metal clusters with novel five-membered FeSCH:CCH2  ring ligand systems.  Intermediates in the formation of ferrocenyl-substituted quinones have been isolated and structurally characterized.

Metal-acetylide and metal-oxo chemistry

        New types of acetylide coupling on mixed-metal clusters, including the first example of tail-to-tail coupling, and influence of secondary bridging ligands on acetylide reactivity have been investigated.  Under aerobic conditions several new oxo-incorporated, acetylide-bridged mixed-metal clusters have been synthesized.  Several other new ligand systems have been generated on mixed-metal clusters, featuring, C-S and C-Se formation and acetylide flip.  Reactivity of metal acetylide with CS2 has resulted in isolation  of thiones and an unusual h3-coordinated S2CCCPh ligand. Electrochemistry and non-linear activity of some of the new systems has been investigated as part of collaboration with colleagues, G. K. Lahiri and B. P. Singh.

Alkynyl Fischer carbene complexes in metal cluster chemistry

          Using the alkynyl unit of the alkynyl Fischer carbene complexes as sites of reactivity with metal carbonyl compounds, several unusual transformations have been facilitated. These include cyclopentannulation, vinyl ether derivative formation and annulation reactions.  Non-linear activity of some of these complexes has been extensively investigated.  The methodology of using alkynyl appendage for cluster growth reactions has been extended to investigation of reactions of phosphaalkynes with chalcogen-bridged metal carbonyl clusters (carried out in collaboration with J. F. Nixon) and reactions of propargyl groups with chalcogen-bridged  dinuclear and trinuclear metal carbonyls.

Synthesis of mixed-metal clusters              

          Methodology of using the lone pairs of some single atom ligands for addition of coordinatively unsaturated metal carbonyl fragments has generated an  avenue for designed construction of metal cluster compounds.  The most significant feature of this strategy is that variation in the transition metal as well as main group element ligands can now be controlled; thus, it has been possible for example to obtain novel mixed-metal, mixed-chalcogen clusters.  Identical cluster core geometries but with variable compositions has enabled systematic studies to be made on variation of properties such as non linear optical activity on composition of clusters.  The methodology has been extended to incorporation of organic fragments to chalcogen-bridged metal carbonyl clusters thus providing ways to modulate reactivity of isostructural clusters.

Ferrocenyl-incorporated metal carbonyl complexes

           Extension of reactivity of new cluster compounds is the reactivity of ferrocenyl and related acetylenes to form organics arising from unusual  oligomerisation and co-oligomerisation reactions.  This will form the thrust of the main research projects in the group for the next few years. Work involves synthesis, spectroscopic and structural characterisation by single crystal X-ray diffraction methods and investigation of electrochemical properties (in collaboration with group of Professor G. K. Lahiri).