SYNTHESIS OF ALKYNYL-SUBSTITUTED 9,10-DIMETALLATRIPTYCENES OF GROUP-14 AND THEIR APPLICATION IN THE PREPARATION OF A NOVEL CLASS OF ORGANOMETALLIC OLIGOMERS

The preparation of((trimethylsilyl)ethynyl)germanium trichloride (4) a llowed the synthesis of various alkynyl-substituted 9,10-dimetallatrip tycenes via a simple one-pot synthetic procedure. For example, reactio n of 4 with o-phenylenemagnesium (1) gave access to 9, 10-(RC=C)(2)-9, 10-digermatriptycenes (5, R = SiMe3; 6, R = H), while reaction of 4 wi th tris(o-(chloromagnesio)phenyl)phenylgermane (2a) furnished 9-(RC=C) -10-phenyl-9,10-digermatriptycenes (7, R = SiMe3; 8, R = H). The synth etic potential of these compounds in the preparation of rigid organome tallic oligomers with conjugated spacers was demonstrated by the oxida tive coupling of 8, which furnished -(10-phenyl-9,10-digermatriptycyl) )-buta-1,3-diyne (9), whose X-ray crystal structure was determined, an d the hydrosilylation of 8 with 10-phenyl-10-germa-9-silatriptycene (3 a), which yielded )-2-(9-(10-phenyl-9-sila-10-germatriptycyl))ethene ( 10).