Novel molybdenum-and tungsten-based catalysts induced stereospecific ring-opening metathesis polymerization (ROMP) of cycloolefins to produce a new class of crystalline polymers. Various monomeric molybdenum(VI) and tungsten(VI) complexes of the general formula M()O)(O-Ar) 4 (M ) Mo or W;(O-Ar)4 is two biphenolate or four phenolate ligands) were prepared. These catalysts exhibited moderate ROMP activity in the presence of cocatalyst such as n-BuLi and Et3Al. The molybdenum and tungsten complexes bearing substituted biphenolate ligands such as oxomolybdenum(VI) bis(racemic-5,5′,6,6′-tertamethyl-3,3′-di-tert-butyl-1,1′-biphenyl-2,2′-diolate) promoted cis and isospecific ROMP of endodicyclopentadiene (cis > 90% and meso > 95%). The novel ternary and quarternary catalysts such as MoOCl 4-biphenolate-n-BuLi (1:2:2) were developed as a new useful methodology to control the stereoselectivity of the ROMP. Hydrogenation of the cis-isotactic poly(endo-dicyclopentadiene)s and poly-(norbornene)s provided novel crystalline polymers with high melting points (295 °C, ∆H ) 50 J/g; 175 °C, ∆H ) 60 J/g, respectively), which can be regarded as a new class of crystalline polymers.

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Supported [RhloSe] catalyst on TiOz converted carbon dioxide into ethanol faster (60 x 10-3 mol h-1 g cat-1) and more selectively ( = 83%) than other supported Rh clusters or [RhloSe] on other inorganic oxides, presumably due to the effects of interstitial Se and the interface of the [RhloSe] cluster and TiOz.Recent environmental conditions require the development of effective catalysts for the reduction of NO,, C02, SO,, benzene, etc. Compared to conventional rhodium catalysts known to produce methane (and other hydrocarbons) from C02 + H2,l we have concentrated on rhodium-based catalysts which convert C02 into ethanol. Some examples of oxygenate syntheses (methanol, acetaldehyde, etc.) from CO + H2 over Rh catalysts are known, but their activities are very low (3.5 X 10-5-2.3 X 10-2 min-1, -673 K).Z4 There are some reports of ethanol synthesis from C02/H2, but here also activities and selectivities were l0w.5 In this study, we report on an efficient synthesis of ethanol from C o r n 2 over supported [RhloSe] clusters prepared from [RhloSe(C0)22]2-.6,7 The promoter effect of interstitial Se (inside the [Rhlo] framework) for ethanol synthesis was considered.

Novel crystalline polymer, crystalline hydrogenated poly(endo-dicyclopentadiene), was developed on the basis of the development of new cis- and iso-specific ROMP catalysts such as MoO(rac-5,5′,6,6′-Me4-3,3′-t-Bu2-2,2′-biphenolate)2.

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