In this paper we report the utility of a variety of silica impregnated bi-and trimetallic catalysts for the conversion of ethanol into 1,3-butadiene. The highest selectivity observed was 67%. The catalysts have been characterised via 29 Si solid-state NMR spectroscopy, TEM, XPS, pXRD and nitrogen adsorption studies. Different silica materials have been investigated as supports and there appears to be a relationship between the pore diameter and the selectivity to 1,3-butadiene. When the same metals were impregnated on non-acidic supports the conversion dramatically reduced.

In this Communication, we report the unprecedented solid-state structures for a series of zinc(II) silsesquioxane complexes. Initial catalytic data for the ring-opening polymerization of rac-lactide are also presented together with analogous heterogeneous species.

Dimeric methylzinc ketoiminate complexes bis{4‐[(2,6‐diisopropylphenyl)imido]pentan‐1‐one}methylzinc, [{L1}ZnMe]2, and bis{1‐phenyl‐3[(2,6‐diisopropylphenyl)imido]butan‐1‐one}methylzinc, [{L2}ZnMe]2 have been synthesized and completely characterized along with the homoleptic zinc complex bis{1‐phenyl‐3[(2,6‐diisopropylphenyl)imido]butan‐1‐one}zinc, [{L2}2Zn] by means of single‐crystal X‐ray structure analysis and NMR spectroscopy. The related dimeric zinc phenoxide–ketoiminate complexes [{L3}Zn]2·(dmso)2, [{L4}Zn]2·(dmso)2, [{L5}Zn]2·(dmso)2, [{L6}Zn]2·(dmso)2 and [{L4}Zn]2·(hmpa)2 (dmso = dimethyl sulfoxide; hmpa = hexamethylphosphoramide) have also been synthesized along with the tetrameric zinc alkoxide–ketoiminate complex [{L7}Zn]4. In preliminary studies the complexes described in this report were assessed for their activity in the ring‐opening polymerization of rac‐lactide, either in the solution state (in the presence of benzyl alcohol initiator), or under industrially preferred melt conditions (130 °C no solvent). It could be shown that these compounds are able to act as initiators for lactide polymerization, with molecular weights (Mn) of up to 102050 g/mol.

a b s t r a c tIn this paper we report the synthesis and characterisation of silsesquioxane tethered Al(III) complexes. The complexes have been characterised by multi-nuclear NMR spectroscopy and depending upon the bulk of the ligand either Al(L)Me 2 or Al(L) 2 Me complexes were isolated. We also report the first solidstate structure of a tethered Alesilsesquioxane complex of the form Al(L)Me 2 . All complexes and heterogeneous analogues were tested for the ring opening polymerisation of rac-lactide, with narrow molecular weight polylactide formed.