Noncovalent Intra‐ and Intermolecular Interactions in Peri‐Substituted Pnicta Naphthalene and Acenaphthalene Complexes

Abstract

Five peri-substituted naphthalene and acenaphthalene complexes (Ph 2 Pn) 2 Naph (E = Sb 1, Bi 3), (Ph 2 Sb) 2 Acenaph (2), (Ph 2 Bi)(Me 3 Sn)Naph (4) and (PhBiNaph) 2 (5) were synthesized and characterized in solution ( 1 H, 13 C NMR, IR) and in the solidstate (sc-XRD). 1-5 show different types of noncovalent intermolecular interactions in the solid-state including NaphÀ H•••π, π•••π and Bi•••π (5) contacts, which were exemplarily (5) quantified by use of density functional theory and local coupled cluster electronic structure theory calculations, demonstrating that the Bi•••π contact provides the main stabilizing contribution. Symmetry-adapted intermolecular perturbation theory calculations showed that this and other contacts are dominated by London dispersion interactions.

Bisstibane–distibane conversionviaconsecutive single-electron oxidation and reduction reaction

“…The Sb-C (2.1769(11) Å, 2.2019(11) Å, 2.1902(10) Å) and Bi-C (2.318(4) Å, 2.326(5) Å, 2.326(5) Å) bonds are rather long due to the large steric crowding in 1 and 2. Despite the increased steric hindrance, the SbÁ Á ÁSb distance in 1 (3.2327(2) Å) is shorter than that in (Ph 2 Sb) 2 Naph (3.2983(6) Å), 15 indicating stronger attractive forces, i.e. ligandÁ Á Áligand dispersion interactions of the i-Pr groups of the Trip substituents.…”

“…In marked contrast, the BiÁ Á ÁBi distance in 2 (3.6742(4) Å) is significantly elongated compared to that in (Ph 2 Bi) 2-Naph (3.4461(4) Å). 15 The elongation of the PnÁ Á ÁPn distance in 2 compared to 1 points to stronger repulsive interactions between the Bi atoms, which is also reflected by the larger distortion of the Naph ligand in 2 (dihedral angles: 12.78(7)1 1, 28.13(29)1 2). In addition, intramolecular CHÁ Á Áp contacts are found for 1 and 2 (Fig.…”

“…While complexes of this type containing lighter pnictogens are known, 12 those of the heaviest elements of group 15, Sb and Bi, are still rare, and they exclusively contain rather strong phosphane donors. 13 We recently reported on dipnictanes Pn 2 Naph 2 (Pn = As, Sb, Bi) 14 and bis(diphenylpnicta)naphthalenes (Ph 2 Pn) 2 Naph (Pn = Sb, Bi) 15 of the heaviest group 15 elements. Due to our general interest in pnictogen-centered radicals, 16 we investigated single electron transfer reactions of the latter.…”

Comparing London dispersion pnictogen–π interactions in naphthyl-substituted dipnictanes

“…5 Peri-substituted naphthalene (naph) metal complexes are promising candidates to investigate LD interactions due to the structural rigidity of the planar naphthalene skeleton and the proximity of the groups in 1,8-position. 6 While this was shown for pnictogen-substituted (I, II) [7][8][9] and heteroatomic Au•••Sb and Hg•••Sb naphthalene complexes, 10 peri-substituted species containing the heaviest and easily polarizable group 15 elements, Sb and Bi, 11 are still rare. Dipnictanes Pn 2 Naph 2 (Pn = As, Sb; type V) were structurally characterized, 12 with Sb 2 Naph 2 forming dimers in the solid-state resulting from dispersion-dominated Sb•••π interactions, whereas the corresponding diarsane and diphosphane Pn 2 Naph 2 (Pn = P 13 , As 12b ) lack any Pn based LD interactions, most likely due to the poorer polarizability of As compared to Sb.…”

“…In addition, Bi⋯π interactions were recently observed in Ph 2 Bi 2 Naph 2 (type IV ). 9 To compare the role of LDF in dipnictanes Pn 2 Naph 2 , we became interested in the structure of the missing member, Bi 2 Naph 2 , since Bi as the largest and softest group 15 element according to the HSAB (hard–soft-acid–base) principle is an ideal candidate for the formation of noncovalent inter- and intramolecular interactions.…”