EXPANDING THE "ROMP TOOLBOX" FOR TISSUE ENGINEERING: ASSESSING THE DESIGN CRITERIA FOR RU- PSEUDOHALIDE INITIATORS

2b even these few suffer from key limitations: in particular, they are difficult to remove from the target materials, and they exhibit too great an extreme of reactivity. Ru-pseudohalide catalysts offer potential solutions to both issues: replacement of the chloride atoms facilitates fine-tuning of reactivity (which could enable access to initiators intermediate between the extremes of 1 and 2a), while the polarity of the aryloxide ligand facilitates chromatographic removal of Ru residues. 3 No systematic study of the pseudohalide initiators in context of ROMP has thus far been undertaken. Here we report the ROMP behaviour of nine RuXX'(IMes)(py)(=CHPh) initiators. Analysis of the roles of ligand geometry, the electronegativity and charge properties of the donor atom, and the capacity of the aryloxide substituents to mediate ligand-ligand interactions, aid in elucidating optimal design criteria. n (M) n (M)