Electronic structure and reaction mechanism as guides to the design of hybrid inorganic-organic polymers

Systematic approaches to the design of organofunctional cyclophosphazene monomers and their conversion to organic backbone polymers with cyclophosphazene substituents are described. A variety of methods including DFT calculations, photoelectron spectroscopy and copolymerization reactivity ratios show that the pi electrons in an olefin attached to a cyclophosphazene undergo sigma polarization towards the phosphazene. This effect may be mediated by electron donors on the olefin or, more effectively, by an insulating function between the olefin and the inorganic ring. Two optimized monomers, P3N3Cl5OR (R=C6H4CH=CH2, (CH2)(4)OC (O)CMe=CH2), have been prepared and their homo- and copolymerization behavior explored. Mixed phosphazene substituent systems have also been developed. Per substituted monomers, P3N3(OR)(6), have been developed and converted to cross linked, hyperbranched and cyclomatrix materials via multi arm polymerization. (C) 2011 Elsevier B. V. All rights reserved.