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Compounds of Germanium and Tin, 18 . Cleavage Reactions of Hexa‐ tert ‐butylcyclotrigermane: Racemate versus Conglomerate Crystallization
Author(s) -
Weidenbruch Manfred,
Hagedorn Annette,
Peters Karl,
von Schnering Hans Georg
Publication year - 1996
Publication title -
chemische berichte
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 0009-2940
DOI - 10.1002/cber.19961290407
Subject(s) - chemistry , hexa , germanium , molecule , crystallization , stereochemistry , tin , cycloaddition , crystallography , metalation , bond cleavage , tellurium , medicinal chemistry , organic chemistry , silicon , catalysis
Treatment of hexa‐ tert ‐butylcyclotrigermane ( 3 ) with CCl 4 , Br 2 , and I 2 furnishes the correspondingly substituted 1,3‐dichloro‐ ( 4 ), 1,3‐dibromo‐ ( 5 ), and 1,3‐diiodotrigermanes ( 6 ). The symmetries of the molecules of 5 and 6 are very similar (point group C 1 ) revealing gauche‐anti conformations and different GeGe bond lengths. However, while 5 crystallizes as a racemate, 6 forms a conglomerate of enantiomerically pure crystals. The X‐ray structure analysis of the 1,3‐dimethyltrigermane ( 7 ) derivative, derived from 6 by a sequence of metalation and methylation reactions, reveals more symmetrical molecules of the point group C 2 which also crystallize as a racemate. Irradiation of 3 leads to tetra‐ tert ‐butyldigermene ( 8 ) and di‐ tert ‐butylgermylene ( 9 ) which could be trapped by addition and cycloaddition reactions with selenium, tellurium, and 3,5‐di‐ tert ‐butyl‐1,2‐benzoquinone.