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Abstract: A number of copolysilanes, (R, R′=Me, Et or Ph; R1 =Me (1–3); Ph (4–6)) bearing carbosilyl side chains have been synthesized by Wurtz coupling method and characterized by GPC, multinuclear (1H, 13C{1H}, 29Si{1H}) NMR and UV spectral studies. A detailed study of 29Si{1H} NMR spectra suggests that the copolysilanes 1–3 are comprised of segregated runs of PhMeSi and RMeSi (R=carbosilyl) units while 4–6 possess many different configurational and conformational environments. The UV spectra of these copolymers reveal a distinct absorption (λ max) at 312–352nm due to σ–σ∗ transition and show a strong dependence on the polymer composition as well as nature of the appended sila substituents. [Copyright &y& Elsevier]

A [10,10]paracyclophane, 5,5,6,6,21,21,22,22-octamethyl-5,6,21,22-tetragerma[10.10]paracyclophane (4a), with two &z.sbnd;R1R2GeGeR1R2&z.sbnd; moieties in the center of two bridges, was prepared. An attempt to synthesize cyclophanes, 4b (R1=Me; R2=Ph) and 4c (R1=R2=Ph) was also made. The products were not analytically pure even after strenuous purification procedure to indicate that a double Wurtz coupling reaction is extremely difficult and necessarily accompanied by formation of polymeric by-products. [Copyright &y& Elsevier]