The stereochemical structure necessary for preparation of perpendicularly arranged cores is provided by a compound of the formula ##STR1## wherein X is a reactive group through which polymeric subunits can be bonded to the compound. In particular, X is advantageously Br. This compound can be synthesized by the reaction of tetrakis(3'-trimethylsilyl-2'-propynyl)silane with zirconocene dichloride and n-butyllithium and adding sulfur monochloride to the reaction product. This produces an adduct in which X is SiMe.sub.3. This adduct may be converted to the bromo compound by reaction with bromine. The tetrakis(3'-trimethylsilyl-2-propynyl)silane may be prepared by forming a magnesium Grignard reagent from 3-bromo-1-trimethylsilylpropyne and reacting the Grignard reagent with silicon tetrachloride.