On the π-bond strengths in higher element homologues of methylenephosphane and diphosphene

Abstract

The n-bond strengths of the structures HXxXH and X \ P, As, Sb, Bi ; Y \ C, Si, Ge, Sn are investigated by means HXxYH 2 , of quantum chemical calculations at the MCSCF level. They are approximated by the magnitudes of the corresponding rotational barriers within the singlet states. Accordingly, the n-bond strength in these systems fades o † with increasing atomic number of the heavy atoms incorporated in the n systems. A comparison is drawn to corresponding p-bond energies, as estimated by the Pauling relationship.

On the Electronic Structures of the 1,3‐Diboracyclobutane‐1,3‐diyls and Their Valence Isomers with a B2E2 Skeleton (E=N, P, As)

“…It is due to the weak (formal) p and s bonding in structures with higher main group elements. [21] Results and Discussion…”

“…It is also of importance for cases in which the s-bonds are weak relative to p bonds; this is generally the case for bonds with higher main group elements. [21] It gives a rationale for the greater importance of dynamic electron correlation for the AsÀB bonds in the studied four-membered ring as compared with the NÀB bonds in the corresponding moieties.…”

Isolation of a Benzene Valence Isomer with One-Electron Phosphorus-Phosphorus Bonds

“…Because of the higher strength of the N-C 7-bond (265 kJ/mol) coinpared with that of the P-C a-bond (180 kJ/mol) (19), derivative 2P is best described by the z\vitterionic structure IV. The dimeri:ation of the diphosphirenyl radical 2P is exothermic ( -163 kJ/mol) and occurs by means of a .rr:%-.rr4: interaction (20) (Fig.…”

First Synthesis and Characterization by Mass Spectrometry and UV‐Photoelectron Spectroscopy of Methylenearsane

“…Several of the simplest low-coordinated compounds bearing a nitrogen, [1] silicon, phosphorus, or sulfur atom have been prepared [2] but few of the corresponding derivatives with a heteroatom of the following rows of the periodic table have been characterized. [3] Due to a lack of any experimental data, the gas-phase proton affinity, [4] the p-bond strength, [5] or the reactivity trends [6] of the simplest arsaalkene, the methylenearsane 1, have only been investigated from a theoretical point of view.…”