Ab Initio Scf-Mo Study of Diphosphecines

Annulenes are intresting compounds in chemistry. Besides their extensive chemistry in theirstructures are also an attractive field of study. So that because of their single and double bonds, [10]-Annulenes have different isomers. Among them in the cis-cis(cc) and cis-trans(ct) isomers, angle strain make structures unstable, and about trans-trans(tt) isomer,although the internal strain reaches to its minmum amount, but the sterc hinderence of internal hydrogens leads to unstability