Configurational and conformational pro perties of ۱,۳,۷,۹-te trastanna - cycl ododeca-۱,۲,۷,۸-tetraene. A hybrid density functional study and natural bond orbital interp retation

Allen es are an im portant class of unsaturated hydrocarbons which contain tw o double bo nds in an orthogonal geo metry.۱,۲ Ring constrai nts bend an d twist the n ormally linear perpendicular allene and enge nder substantial strain and resultant kinetic reactivity.۳ Mono cyclic mediumring dialle nes with th e allene gro ups in a ring that has mo re than nine members appear to be fairly stable. Simple monocyclic di allenes poss ess two chiral centers a nd should ex ist in two d iastereoiso meric form s, one diasereisomer being race mic and the other a meso comp ound.۴ In this work, we have investigated computationally the structural, conformational prope rties of ۱,۳,۷,۹-tetrasta nna-cyclododeca-۱,۲,۷,۸ -tetraene, b y hybrid density functional based method (B ۳LYP/Def۲ -TZVPP) a nd natural bond orbital interpre tation, using the GAU SSIAN ۰۳ package of programs.۵,۶ In addition, the allenic bonds natur e (population and bondi ng orbital deviation) a nd the stability of va rious conf ormations o f (±)and mesoconfigurations of ۱,۳,۷,۹-tetrastanna-cy clododeca-۱,۲,۷,۸-tetraene, was systematically and quantitatively corr elated using NBO analy sis.۶

کلیدواژه ها:

DFT ، NBO ، allenic compoun ds