Akademik Veri Yönetim Sistemi
JOURNAL OF MOLECULAR STRUCTURE-THEOCHEM, cilt.631, ss.87-91, 2003 (SCI-Expanded)
Certain Huckel type even cyclacenes having one (S-R-type) or two (P-R- and C-R-types) -CH2CH2- bridge(s) are considered for AMI (RHF) type semiempirical quantum chemical calculations. In P-R-type structures the bridges connect two benzenoid rings of the corresponding cyclacene in such a way that an embedded para-cyclophane skeleton happens. The C-R-types contain two phane bridges which are crossly oriented. All these structures considered were found to be stable but endothermic in nature. Also, it has been found that bridging is highly effective on the energetics of these systems. In the homologous series Of P-R-type structures, alternately increasing and decreasing values of DeltaH(f) values occur. In the C-R-type structures, the HOMO and LUMO energy levels similarly exhibit local minima and maxima. (C) 2003 Elsevier B.V. All rights reserved.