Zirconium Complexes for the Production of Polycarbonates

Nozaki s zirconium(iv) BOXDIPY initiator was inactive for the copolymerisation of PO/carbon dioxide with the addition of 1 equivalent of [PPN]Cl (2.0 MPa carbon dioxide, 60 °C) forming the cyclic carbonate in 100% yield. ° Tbe complex was able to produce a polycarbonate with CHO, although the proportion of ether linkages was high. Titanium(iv) and germanium(iv) complexes were also screened, with more success than the zirconium(iv) analogue. In 2014 Ko prepared a series of zirconium(iv) amine-bis(benzo-triazole) phenolate complexes for the ROP of rac-LA and the production of 

It has been shown that the Lewis-acid nature of the Zr centres is key for this reaction. Zirconium-containing catalysts are amongst some of the most active heterogeneous catalysts for this process in the literature, with a wide substrate scope and water tolerance. Moreover, in recent years there has been a minirenaissance in the development of catalysts for the conversion of ethanol to butadiene - some of the most effective utilise Zr02, illustrating its importance in this area.  

Greenwood and A. Earnshaw, Chemistry of the Elements, Pergamon Press, 1989. 

Whitelaw, M. D. Jones, M. F. Mahon and G. Kociok-Kohn, Dalton 

Fukuoka, M. Kawamura, K. Komiya, M. Tojo, H. Hachiya, K. Hasegawa, M. Aminaka, H. Okamoto, I. Fukawa and S. Konno, Green Chem., 2003, 5, 497-507. 

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