peri Interaction in Naphthalene Derivatives

Hypervalent Adducts of Chalcogen-Containing peri-Substituted Naphthalenes; Reactions of Sulfur, Selenium, and Tellurium with Dihalogens

“…56,57,58,60 The bulky atoms are constrained in close proximity by the rigid backbone at a distance shorter than the sum of van der Waals radii for the two interacting atoms. 56,57,58 Steric strain caused by the crowding of substituents can be released through bond formation or if weak attractive non-covalent interactions exist between tightly packed atoms.…”

“…56,57,58 Steric strain caused by the crowding of substituents can be released through bond formation or if weak attractive non-covalent interactions exist between tightly packed atoms. 60,61 As non-bonded distances decrease relative to the sum of van der Waals radii, weak non-covalent interactions become more covalent in nature and the steric interaction is reduced. 62 Distortion away from the "ideal" naphthalene geometry also helps alleviate steric strain and occurs via inplane and out-of-plane deviations of the exocyclic bonds and buckling of the usually rigid backbone.…”

Sterically Restricted Tin Phosphines, Stabilized by Weak Intramolecular Donor–Acceptor Interactions

“…1 Rigid polycyclic aromatic hydrocarbon backbones naphthalene 2 and acenaphthene 3 provide such spacial proximity of atoms or groups, with a double substitution at the close contact peripositions ensuring the interacting atoms, are located in unavoidably congested environments. 4,5 Whilst two hydrogen atoms (sum of the van der Waals radii (Σr vdW ) of two hydrogen atoms = 2.18 Å) 6 can be accommodated comfortably at the adjacent peri-positions in these systems (peridistances 2.5/2.7 Å, respectively), 2,3 when larger heteroatoms are constrained in such cramped environments they naturally experience considerable steric hindrance. The repulsion between these bulky groups or atoms often results in the usually rigid naphthalene backbone deforming away from the ideal structure through in-and out-of-plane distortions of the exocyclic peri-bonds or buckling of the organic framework.…”

“…4,5,7,8 The unique feature of peri-substituted systems, however, is their ability to relieve steric strain and achieve a relaxed geometry via the formation of a direct bond between the peri-atoms. 5,9 The unique competition between attractive bonding interactions and steric repulsion in these systems accounts for their unusual reactivity and structure, 4,5,10 but whilst the nature of the intramolecular interactions in clear-cut cases is unambiguous, there are many examples which arouse conflicting interpretations of the bonding situation, with arguments for and against the existence of attractive forces and contention over whether or not the peri-atoms are linked by a chemical bond. [11][12][13][14][15] This is typified by the controversial debate surrounding the potential occurrence of hypercoordination resulting from intramolecular bond formation in species containing the 8-dimethylaminonaphth-1-yl (DAN) fragment.…”

Bridging the Gap: Attractive 3c–4e Interactions in peri‐Substituted Acenaphthylenes

“…The subsequent nonbonded intramolecular interactions which result from the direct overlap of orbitals can either be repulsive due to steric hindrance or attractive in the form of weak or strong bonding. [12,13] When electron density is delocalized over formally nonbonded atoms, the degree to which the delocalization contributes to the bonding between these atoms is of particular interest. [8,[14][15][16][17][18][19] Heavier third and fourth row peri-substituents, susceptible to hypervalent bonding, can be forced to interact well within the sum of van der Waals radii.…”