Orbital Phase Design of Acyclic Electron Localizing and Delocalizing π-Conjugated Poly ions and Related Systems

Abstract

Acyclic localization-delocalization of electrons in π-conjugated hydrocarbon polyions was predicted in terms of the continuity-discontinuity of the phase of the component orbitals. Many pairs of electron-localizing and -delocalizing conjugated polyions were designed as the model systems of which the relative stabilities have not been explored so far.

Pentagon Stability: Cyclic Delocalization of Lone Pairs through σ Conjugation and Design of Polycyclophosphanes

“…The continuity−discontinuity of the orbital phase 1 underlies the stabilities of the cyclic conjugated systems, i.e., the Hückel rule for aromaticity and the Woodward−Hoffmann rule for pericyclic reactions. Applications were recently made to the unusually short distance between the silicon atoms in disilaoxiranes and 1,3-cyclodisiloxanes and to the geminal bond participation in organic reactions. , The finding of cyclic orbital interaction involved even in acyclic conjugation has expanded the application of the orbital-phase theory to acyclic conjugated systems such as the regioselectivities of organic reactions, the abnormally acute L−M−L angles in ML 2 and ML 3 complexes, the relative stabilities of π-conjugated polyions and diradicals, those of σ-conjugated molecules and diradicals, and the conformational stabilities of the substituted alkenes and alkynes…”

Orbital Phase Control of the Preferential Branching of Chain Molecules

“…So the orbital phase continuity requirement is essentially equivalent to inequality 4. It should be noted that the phase conditions of continuity are the same for both cyclic 11 and acyclic, − closed-shell 12-17 and open-shell, , and π-conjugated 17 and σ-conjugated systems…”

“…The continuity−discontinuity of the orbital phase was shown to underlie the stabilities of the cyclic conjugated systems, i.e., the Hückel rule for the aromaticity and the Woodward−Hoffmann rule for the pericyclic reactions. In the past twenty years, the finding of cyclic orbital interaction involved even in acyclic conjugation has expanded the application of the orbital phase theory to the acyclic conjugated systems such as the regioselectivities of organic reactions, the abnormally acute L−M−L angles in ML 2 14a and ML 3 14b complexes, the relative stabilities of isomers of π-conjugated polyions, and the conformational stabilities of the substituted enamines and vinyl ethers . The usefulness of the simple theory was also demonstrated by the successful prediction of the stabilities of the π-conjugated diradicals and the σ-conjugated triplet diradicals E 4 H 8 and E 5 H 10 (E = C, Si, Ge, Sn) .…”