Ring opening metathesis polymerisation ROMP

Since one of the substrates is a cyclic alkene there is now the possibility of ring-opening metathesis polymerisation (ROMP) occurring which would result in the formation of polymeric products 34 (n >1). Since polymer synthesis is outside the scope of this review, only alkene cross-metathesis reactions resulting in the formation of monomeric cross-coupled products (for example 30) will be discussed here. 

Fig. 6.3 Ring-opening metathesis polymerisation (ROMP) of norbornene (the two cyclohexyl groups on each of the P atoms are omitted for the sake of clarity according to Astruc et aI.)...

Up to third-generation ruthenium-carbene complexed dendrimers (Fig. 6.2) prepared by Astruc et al. contain a chelating diphosphane, which is sufficiently stable for construction of the dendritic architecture while also sufficiently reactive to permit synthesis of the dendrimer depicted in Fig. 6.3 by ring-opening metathesis polymerisation (ROMP) [3]. 

This facile solution for catalyst immobilisation follows a more complex approach reported by Mayr et al. [246], This research group attached the imidazolium salt to a nor-bomene unit that was then subjected to a ring opening metathesis polymerisation (ROMP) reaction to form the polymeric NHC precursor (see Figure 4.77). The ROMP reaction had to be carried out with a molybdenum based Schrock catalyst because the ruthenium based Grubbs catalyst did not provide an endgroup that could be quantitatively capped with a suitable final endgroup. 

The structure-activity importance of synthetic pyridinium-based polymers synthesised via the ring-opening metathesis polymerisation (ROMP) of norbornene has been reported these polymers were expected to directly affect the bacterial membrane [24-26]. The interaction of these polymers with a phospholipid membrane model has been investigated using the fluorescent dye, calcein, embedded in unilamellar vesicles. 

To conclude this section, an example is given of the application of statistical models to examine double bond sequences in polymers with unsaturated backbones. The presence of backbone unsaturation leads to the occurrence of cisitrans isomerism and this can be treated entirely analogously to comonomer sequence. Ivin [42] and others have used NMR spectroscopy extensively to study the microstructure of polymers prepared by transition metal catalysed ring-opening metathesis polymerisation (ROMP) such as polynorbornene (PNB). 

NEW MATERIALS FROM THERMAL AND PHOTOINDUCED RING OPENING METATHESIS POLYMERISATION (ROMP/PROMP)... 

Seven-coordinate bimetallic compounds are also active unicomponent catalysts in the ring-opening metathesis polymerisation (ROMP) of cyclic olefins. The first step in this reaction is the coordination of olefin to metal. However, only in the reaction with a chelating ligand such as norbornadiene (NBD) was it possible to isolate and characterise the reaction product. In the reaction with NBD chloride bridge splitting in the binuclear compound of tungsten(II) by a diene molecule occurs very easily and monomeric seven-coordinate compounds are formed (Eq. 6) [48]. 

Polymers formed by the ring-opening metathesis polymerisation (ROMP) reaction [54] exhibit a wide variety of microstructures which may be evaluated by specctroscopic techniques. The first ROMP polymers were analysed by IR spectroscopy [55], but that can only determine the absolute stereochemistry of... 

Hanson et al. have developed a synthesis of triazoles (91) and utilisation of oligomeric triazole phosphates (OTP) (89) for direct triazolation of N-, O- and -nucleophilic species (90) in a click -capture ring-opening metathesis polymerisation (ROMP)-derived protocol (Scheme 22). ... 

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