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Synthesis and Properties of a Bis(2‐buteno)‐Bridged Bis(adamantane): X‐ray and Molecular Dynamic Studies of the trans, trans Isomer
Author(s) -
MlinarićMajerski Kata,
Pavlović Dražen,
Milinković Vjekoslav,
KojićProdić Biserka
Publication year - 1998
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/(sici)1099-0690(199806)1998:6<1231::aid-ejoc1231>3.0.co;2-1
Subject(s) - chemistry , adamantane , stereochemistry , diamondoid , medicinal chemistry , molecule , organic chemistry
The synthesis of the trans , trans isomer of the bis(2‐buteno)‐bridged bis(adamantane) 3 has been developed, and its structure was established by spectral and X‐ray structure analysis. Since the results of dynamic NMR studies indicate that 3 is conformationally mobile and the transition‐state free energy (Δ G c ≠ ) required to interconvert two equivalent con‐formers was estimated to be ca. 60 kJ mol −1 , the lowest energy conformer was subjected to a molecular dynamic simulation at 323 K in the gas phase. Three conformations 3a , 3b and 3c were found. The conformations 3a and 3c have anti ‐oriented adamantane units, while in 3b the adamantane molecules occupy the syn conformation. By analysing the conformational processes in macrocyclic diene 3 , it was found that the calculated conformation 3a with molecular symmetry of C 2h is very close to that found in solution at –50 °C, but differs from that which was observed in the solid state by X‐ray‐crystallographic analysis.