Azoderivatives show faster thermal cis-to-trans isomerisation kinetics when they are under the influence of the nematic mean field than dissolved in isotropic solution. The local order parameter induced in the azo-dye by the host mesogen determines the rate of its thermal cis-to-trans isomerisation process. In this way, AZO6-LC mixtures with the same order parameter exhibit identical isomerisat...

Experimental studies of the ring-closing metathesis reaction of 1,8-nonadiene and the ROMP reaction of cycloheptene show that the rate of isomerisation is not correlated to the initiation rate of the pre-catalyst, and that the absence of phosphine leads to a greatly increased rate of isomerisation. A range of pre-catalysts and solvents were probed and it is proposed that the isomerisation is me...

The insertion of internal olefins (hydroalumination) and chain walking isomerisation at di-n-octylaluminium hydride [Al(Oct)2H], promoted by zirconocene dichloride [Cp2ZrCl2] has been studied. The reaction between [Cp2ZrCl2] and [Al(Oct)2H] in non-polar solvents leads to clusters containing bridging hydride ligands between Zr and Al. This system promotes hydroalumination of 1-octene but is larg...

A bi-enzymatic cascade for the redox-isomerisation of allylic alcohol is presented. Coupling of an alcohol dehydrogenase to an enoate reductase has been successfully applied in one pot for the isomerisation of an allylic alcohol to the corresponding ketone. Critical parameters for yield and selectivity have been investigated.

Data from a previous study about the effects of pH and of linolenic acid (C18:3n-3) and linoleic acid (C18:2n-6) concentrations on C18:2n-6 biohydrogenation in ruminal cultures were used to calculate the rates and efficiencies of the three reactions of C18:2n-6 biohydrogenation (isomerisation of C18:2n-6 to CLA; reduction of CLA to trans-octadecenoic acids; reduction of trans-octadecenoic acids...

The insertion, elimination and isomerisation of octenes with di-n-octylaluminium hydride [HAl(Oct)2], tri-n-octylaluminium [Al(Oct)3] and sec-octylaluminium species have been studied as individual steps in a putative aluminium based contrathermodynamic olefin isomerisation process. While elimination of 1-octene from [Al(Oct)3] is energetically unfavourable, the process is driven by high tempera...

Aromatic diols containing bis (azo) and bis (o-nitrobenzyl) chromophores viz., (4hydroxyphenylazo)-2,2/-dinitrodiphenylmethane, 4-hydroxy-3-methylphenylazo-4/-hydroxyphenylazo-2,2/-dinitrodiphenyl methane and bis (4-hydroxy-3-methylphenylazo)-2-dinitrodiphenyl methane were synthesized from 4,4-diamino-2,2/-dinitrodiphenylmethane and phenol/0-cresol. As a result of photolysis, the azo group of t...

Hydrotalcite catalysed liquid phase glucose isomerisation in EtOH.

Allylic alcohols can be isomerised into carbonyl compounds by transition metal complexes. In the last few years, catalyst design and development have resulted in highly efficient isomerisations under mild reaction conditions, including enantioselective versions. In addition, the isomerisation of allylic alcohols has been combined with C-C bond forming reactions when electrophiles such as aldehy...

Lycopene in fruits and vegetables occurs mostly (80-97 %) in the all-E configuration, whereas a considerable proportion of lycopene in the human body is present as Z-isomers. The Z-isomers offer potentially better health benefits and show improved antioxidant activity in vitro when compared with the all-E-isomer. The absorption of dietary lycopene is a complex process involving transfer of the ...