Naphthalene and Related Systems peri‐Substituted by Group 15 and 16 Elements

Abstract

Synthetic and bonding aspects of heavier Group 15 (P, As, Sb, Bi) and 16 (S, Se, Te) peri-substituted naphthalenes, are discussed in this review. An important and unifying feature of the chemistry of these systems is the lively discussion about the nature of the interaction between peri-atoms. Are atoms bonded when they are closer than the sum of their van der Waals radii? Is there any (weak) bonding, or just a strained repulsive interaction? Positioning atoms of Group 15 and 16 at the naphthalene 1,8-positions provides leading systems with which to study these bonding issues.

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.…”

Platinum Complexes of 5,6‐Dihydroacenaphtho[5,6‐cd]‐1,2‐dichalcogenoles

“…The homogeneity of the new compounds was, where possible, confirmed by microanalysis. 5,cd]-1,2-dithiole (AcenapS 2 ) L1 and 5,6-dihydroacenaphtho [5,6-cd]-1,2-diselenole (AcenapSe 2 ) L2 were prepared following standard literature procedures [23] starting from 5,6-dibromoacenaphthene. [24] Synthesis of the platinum metal complexes was based on previously well documented routes to complexes of 1,8-disubstituted naphthalene chalcogenides and related polyaromatic hydrocarbon compounds.…”

“…[4] A number of investigators have utilised this characteristic of the naphthalene scaffold to study bonding interactions in main group systems, where molecular geometry is determined by a competition between attractive (covalent and weak) forces and repulsive interactions (steric strain). [5,6] The distinguishing feature of peri-substitution is the ability to achieve a relaxed geometry via formation of a direct bond between the two peri-atoms. [7] Furthermore, proximity effects associated with peri-substitution favours complexation to a bridging metal species, providing the correct spacial arrangement for bidentate coordination.…”

High-resolution X-ray diffraction determination of the electron density of 1-(8-PhSC10H6)SS(C10H6SPh-8′)-1′ with the QTAIM approach: evidence for S4 σ(4c–6e) at the naphthalene peri-positions

“…A substantial number of compounds containing the s(4c-6e) interaction have been reported. 6,8,9 Benzene substituents in the 1,2-positions, naphthalene substituents in the 1,8-positions and related systems serve as good spacers for the formation of these interactions.…”