Poly carbenes

Generation and characterization of high-spin organic molecules 210 Cross-conjugated poly(carbenes) 210 Other high-spin molecules 215... 

Fig. 9 Hiickel MO diagrams of diphenykarbene [15 m = 1], m-phenylenebis(phenylcarbene) [15 m = 2] and poly( i-phenylene-carbenes) [15],...

Encouraged by the experimental finding (Itoh, 1967 Wasserman et al., 1967) that the dicarbene [15 m = 2] ( = [3]) had a ground quintet state, i.e. all four spins were ferromagnetically coupled, Iwamura and Itoh have been engaged in a project directed towards the construction of the higher series of poly(carbenes) [15], [23] and [24] (Iwamura et al., 1985 Teki et al., 1983, 1985, 1986). 

A Comparative Study of Three Poly-DVB-supported Ru Carbenes... 

Method of preparing random poly(amide-fe-ester) derivatives through depoly merization/repolymerization of cyclic polyesters then coreacting with lactam derivatives using a nonmetallic carbene catalyst This method for preparing polyester amides is unreported. 

Polyhedral carboranes (continued) seven-vertex carboranes, 3, 58 six-vertex carboranes, 3, 56 small carborane syntheses, 3, 54 subicosahedral carborane geometrical patterns, 3, 50 subicosahedral and icosahedral, 3, 51 supraicosahedral, characteristics, 3, 96 ten-vertex carboranes, 3, 60 thirteen-vertex carboranes, 3, 100 tricarbaborane synthesis, 3, 54 twelve-vertex carboranes, 3, 98 Polyhedral skeletal electron pair theory, Ru and Os tetranuclear clusters, 6, 874-875 Poly(iV-heterocyclic carbene) ligands... 

Linear and 2D branched poly(diarylcarbene) systems95 were much pursued as prototypical potential magnetic systems (Fig. 8). For example, Iwamura and coworkers developed synthetic methodologies to put many diazo sites (photochemical carbene precursor sites) into proper connectivity to photogenerate all or most of the carbene sites. Itoh and coworkers developed methods to obtain and analyze HS ESR spectra of polycarbenes and polycarbene ions.96 Although... 

The concept of transesterifications was used for polymerization reactions by Hedrick and colleagues [76]. Various biodegradable polyesters were synthesized with the l,3-dimethylimidazol-2-ylidene carbene in THF at 25 °C. Polymers such as poly(e-caprolactone) were obtained with no need of organometallic catalysts, as in classical methods. Poly(ethylene terephthalate) (PET) 97 was synthesized in the ionic liquid 98, which functions as the reaction medium and, at the same time, as a precatalyst that is activated (99) with KOt-Bu. Dimethyl terephthalate (DMT) 100 was condensed with an excess of ethylene glycol 101 to generate 102. The melt condensation of 102 was performed under vacuum using a heating ramp to 280 °C. 

Similar behaviour to carbon monoxide is displayed by other heterounsatur-ated monomers of carbene-like structure, isocyanides, which homopolymerise in the presence of nickel-based catalysts, yielding polymers with a carbon-carbon main chain, poly(iminomethylene)s [60],... 

Paracyclophane-1,9-diene is an interesting cyclic diene monomer with a very strained ring. It has been easily polymerised with a tungsten carbene complex [148] to low molecular weight poly(p-phenylene vinylene) [148] ... 

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