Carboxylate species, structure

The growing species in living block copolymerisation systems may change when changing the comonomer to build the next block or they may retain their structure. For instance, the polymerisation of /J-butyrolactonc with an aluminium porphyrin catalyst such as (tpp)AlCl proceeds via aluminium carboxylate species [scheme (10)] which are converted to aluminium alcoholate species when the polymerisation of propylene epoxide is carried out from the living polyester as shown schematically below [195] ... 

Carbondioxide adsorption is another example of molecular adsorption which has been studied quite extensively in the past. While for some time is was generally accepted that CO2 forms carbonates with chromia surfaces very readily upon exposure, it was recently observed that carboxylate species may be formed. TDS spectra indicate [111, 112] that there are more weakly and less weakly bound CO2 species on the surfaces. We have studied the nature of those species by various techniques including infrared spectroscopy. Fig. 23 shows several sets of IR spectra. The pair of sharp bands around 2300 cm can easily be assigned to the more weakly bound CO2 with only slightly distorted structure... 

Fig. 8. Model of the structure of thallium(I) carboxylate species in highly concentrated aqueous solutions. Temperature = 25°C. (a) Formate species. [Tl]t t = 10.8 M, [H2O]/ [TKD] = 2.6, [formate ]/[Tl(I)] = 1.0. Thalliumd) ions are fourfold coordinated by three formate oxygens and one weakly bound water molecule (not shown), (b) Malonate species. [TlJtot = 9-0 M, [H20]/[T1(D] = 3, [malonate "]/[Tl D] = 0.5. Fourfold oxygen coordination of thalliumd) ion is shown only for one T1(I) atom. Some interatomic distances are given (in angstroms). From Yamaguchi et al. 177).

Figure 36. The structure of FAGVUF [Ln(CgH3S07)(H20)4]. The linker is 5-isophthalic acid, a mixed sulfonate-carboxylate species. Gray tetrahedra are point-shared sulfonate groups.

Fig. 13 Structural motifs in carboxylate organoaluminum carboxylate species...

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