Permethylated ring

Such bis(pentamethylcyclopentadienyl) complexes exhibit extremely high activities in ethylene homopolymerization but the steric constraint of the permethylated rings does not allow insertion by higher a-olefins. Less constraining ligand environments like that in (6) (Figure 10) result in dimerization with consequent loss of activity. Compound (6) is a more... 

Hydride abstraction from the permethyl ring of Cp Ru gives the 161 ... 

In any event, between 1951 and 1975, no papers appeared on polysilane high polymers. However, linear permethylpolysilanes of the type MelSiMezhiMe were prepared and studied, especially by Kumada and his students,(5) and cyclic polysilanes were being investigated in several laboratories.(6,7) Studies of the permethyl-cyclosilanes, (Me2Si)n where n = 4 to 7, showed that these compounds exhibit remarkable delocalization of the ring sigma electrons, and so have electronic properties somewhat like those of aromatic hydrocarbons.(6)... 

The Mg promoted reaction between perchloropropene (232) and permethyl-l,3-dichlorotrisilane (233) produces an acetylenic structure with two l,2,3-trisilacyclopent-4-ene rings (234) (Equation (19)) <93JA3111>. 

Guan et al. have recently published the preparation of galactitol and D-mannitol-derived permethylated polyesters 62 [41] and the living ring-opening polymerization of the galactonolactone 20 [42] giving polyester 63. The latter exhibited protein resistance. 

Ferrocenyl-based polymers are established as useful materials for the modification of electrodes, as electrochemical biosensors, and as nonlinear optical systems. The redox behavior of ferrocene can be tuned by substituent effects and novel properties can result for example, permethylation of the cyclopentadienyl rings lowers the oxidation potential, and the chaige transfer salt of decamethylfer-rocene with tetracyanocthylene, [FeCpJ]" (TCNE], is a ferromagnet below = 4.8 K, and electrode surfaces modified with a pentamethylferrocene derivative have been used as sensors for cytochrome c These diverse properties have provided an added impetus to studies on ferrocene dendrimers. 

The permethylated cyclopolysilanes are colourless, crystalline solids. The hexamer (Me2Si)e adopts a chair conformation with negligible methyl-methyl interactions in the solid state, whereas the larger rings (Me2Si) ( = 13 or 16) are distorted in response to endocyclic interactions between methyl groups (see Figure 6.1). In solution, the permethylated cyclopolysilanes show only sharp... 

Cobalt(l)-mediated ring contraction of a permethylated pentasilacycloheptyne gives the bicyclooctene 27 derivative in isolated yields of about 72% <1996OM3606>. 

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