Tricarbonylchromium complexes of [5]- and [6]metacyclophane: an experimental and theoretical study

The role of non-covalent interactions in 4-hydroxybenzylamine macrocyclisation: computational and synthetic evidence

4-hydroxybenzylamine's intermolecular interactions and their possible influence on the course of 4-hydroxybenzylamine's reaction with formaldehyde are analysed in this article. Computational calculations established that 4-hydroxybenzylamine forms dimers in solution by O-H⋯N hydrogen bonds; such dimers are stabilised by π-stacking interactions. These cyclic dimers' formation led to obtaining a 12-atom azacyclophane through 4-hydroxybenzylamine's reaction with formaldehyde.

Adducts of the Parent Boraphosphaketene H2 BPCO and their Decarbonylative Insertion Chemistry

The first examples of Lewis base adducts of the parent boraphosphaketene (H2 B-PCO) and their cyclodimers are prepared. One of these adducts is shown to undergo mild decarbonylation and phosphinidene insertion into a B-C bond of a borole, forming very rare examples of 1,2-phosphaborinines, B/P isosteres of benzene. The strong donor properties of these 1,2-phosphaborinines are confirmed by the synthesis of their π complexes with the Group 6 metals.

Analyzing Reaction Rates with the Distortion/Interaction-Activation Strain Model

The activation strain or distortion/interaction model is a tool to analyze activation barriers that determine reaction rates. For bimolecular reactions, the activation energies are the sum of the energies to distort the reactants into geometries they have in transition states plus the interaction energies between the two distorted molecules. The energy required to distort the molecules is called the activation strain or distortion energy. This energy is the principal contributor to the activation barrier. The transition state occurs when this activation strain is overcome by the stabilizing interaction energy. Following the changes in these energies along the reaction coordinate gives insights into the factors controlling reactivity. This model has been applied to reactions of all types in both organic and inorganic chemistry, including substitutions and eliminations, cycloadditions, and several types of organometallic reactions.