Chlorine bulky

It is also possible to iaterfere with the polymerization by attaching at the alpha positions either too many groups, or groups which are too bulky. Four chlorine atoms (12) or four methyl groups (13) seem to be sufficient to hinder the production of polymer. These crowded -xylylene monomers can be polymerized, but not through a VDP process. 

FABMS has shown that the bulky Pr PCEhCHhPPr forms the dimeric [ TcNCl2(P-P) 2]. The 3,PNMR spectrum indicates a chlorine bridged structure [57]. The reaction of MePhNNH2/dppe/[TcOCl4] in MeOH, however, yields a cationic complex formulated as the oxo-imido tra .v-[TcO(NH)(dppe)2]+. Few details are available, but the crystal structure determination showed marked asymmetry in the bonding of the two axial ligands [74]. A distinction between the [HN=Tc=OJ+ core and the tautomeric [N=Tc-OH]+ core should be possible... 

Here there is no formal electronic bar to interaction between the electrons, i.e. pairing to form the diamagnetic species (137) but this does not in fact happen, because the bulky chlorine atoms in the o-positions prevent the benzene rings from attaining a conformation close enough to coplanarity to allow of sufficient p orbital overlap for electron-pairing to occur. 

Interestingly enough, some biradical character has been observed in systems similar to (136) even when there are no bulky chlorine atoms present to inhibit delocalisation sterically. Thus with the system (138) = (139),... 

Alkadienephosphonates with bulky substituents at the allene moiety react with chlorine with formation of l,2-oxaphosphole-2-oxide intermediate 69... 

Poly(ether ketone)s 3, 4, 5, 6, and 7 were soluble in polar aprotic solvents such as DMAc and NMP and in chlorinated solvents such as chloroform. The improved solubility of these fluorinated poly(ether ketone)s can be explained by the presence of both the flexible hexafluoroisopropylidene groups and the bulky 1,4-naphthalene moieties, which inhibit polymer crystallization and facilitate the penetration of solvent molecules between the polymer chains. 

It has an excellent outdoor life period and good strength. It is amorphous because of the presence of bulky side groups in the molecules. It is resistant to many chemicals but soluble in organic solvents like ketones, chlorinated hydrocarbons and esters. It can be thermally depolymerised to give back the entire quantity of monomer. 

By comparing CPK models of the Meisenheimer intermediates which should be formed in each case, steric hindrance for substitution of the nitro group (intermediate 30) should be larger than for substitution of any of the chlorine atoms (intermediates 31, 32). This is in accordance with the observed results where bulkiness of the butylamine leads to a diminution of the corresponding nitro-substitution product. Nevertheless, as we have... 

N-Methyl-E-cinnamide and p-chloro- -cinnamide were consequently tested as suitable additives. Both cause cinnamide crystals to grow as thin 100 plates (Figure 4c). In the presence of the former, the TV-methyl group of the additive molecule, which invariably adopts the synplanar conformation 3a (SO), prevents formation of the dimer, thus inhibiting the attachment of additional cinnamide molecules along a. The additive p-chloro-E-cinnamide inhibits the deposition of oncoming 100 layers, due to steric hindrance induced by the bulky chlorine atom. 

Zr or Ti) [Busico et al., 2003a Gibson and Spitzmesser, 2003 McKnight and Waymouth, 1998 Shapiro et al. 1990]. X is chlorine or methyl, and R is usually a bulky alkyl group such as t-butyl or an aryl group. 

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