The research project is directed towards the synthesis of novel, well-dcfined, ansabis(imido)chromium complexes, isolobal analogues of the technologically important group 4 ansametallocenes.
Figure 1. The isolobal relationship between dr metals of group 4 metallocenes (Ti. Zr, Hf) and group 6 bis(imido) complexes (Cr, Slo,W). The "bite angle" of the ligand is crucial for the catalytic activity of the complexes as demonstrated for ansa-zirconocene compounds. The bite angle will be tailored by adjusting the length and type of the linkage, between the two imido groups. The imido groups stabilises the metal in its highest oxidation state and it offers a number of options for different organosubsituents. These tools will be used to modify the ligand frame of the complexes. Ansa-bis(imido)chromium dichloro complexes will be the precursors for the synthesis of carbyl, alkylidene and cationic complexes. The catalytic activity of these complexes in olefin polymerisation and ROMP (ring opening metathesis polymerisation) will be investigated. Figure 2. Schematic representation of bis(imido, ansa-bis(imido) and cationic ansa-bis(imido) chromium complexes.
The host research group has the expertise and facilities required for the successful development of the project. Professor Gibson's group has good contacts with industry which will provide an excellent opportunity to explore the potential applications of the complexes. This training will enable me to develop skills relevant to both the academic (ligand design and complexes characterisation) and industrial environments (catalyst testing and polymer studies).