Synthesis and Molecular Structure of Pseudo‐Hexacoordinated Pnictines Bearing 2‐Phenylpyridine Ligands

• Published in: European journal of inorganic chemistry Vol. 2020; no. 46; pp. 4373 - 4379
• Main Authors: Sakabe, Masato, Ooizumi, Akihisa, Fujita, Wataru, Aoyagi, Shinobu, Sato, Soichi
• Format: Journal Article
• Language: English
• Published: WEINHEIM Wiley 13.12.2020; Wiley Subscription Services, Inc
• Subjects: Antimony; Bismuth; Chemical bonds; Chemical synthesis; Chemistry; Chemistry, Inorganic & Nuclear; Crystal structure; Density functional calculations; Inorganic chemistry; Intramolecular coordination; Ionic interactions; Ligands; Main group elements; Mass spectrometry; Molecular structure; Nitrogen; NMR spectroscopy; Physical Sciences; Pnictogens; Science & Technology; Structure elucidation; Main group elements; ACTIVATION; Pnictogens; Density functional calculations; ALDEHYDES; STIBINES; FLUORIDE; PSEUDOPOTENTIALS; HYPERVALENT; CHEMISTRY; Intramolecular coordination; Structure elucidation; ORGANOANTIMONY COMPOUNDS; DRINKING-WATER; DERIVATIVES
• ISSN: 1434-1948; 1099-0682
• DOI: 10.1002/ejic.202000795

The pseudo‐hexacoordinated organo‐pnictogen(III) compounds tris[2‐(2‐pyridyl)phenyl]stibine [(ppy)3Sb, 1] and tris[2‐(2‐pyridyl)phenyl]bismuthine [(ppy)3Bi, 2], which bear three 2‐phenylpyridine (ppy) ligands, were prepared and isolated from the reaction of 2‐(2‐lithiophenyl)pyridine with the corresponding pnictogen(III) chloride (PnCl3; Pn = Sb, Bi). Compounds 1 and 2 were characterized using NMR spectroscopy, mass spectrometry, and elemental analysis. Their solid‐state structures were determined using single‐crystal X‐ray diffraction analysis, which revealed similar pseudo‐hexacoordinated, distorted facial octahedral bonding geometries around the central pnictogen atoms, wherein the three pyridyl groups coordinate to the pnictogen atoms via three weak LP(N)→σ*(Pn–C) donor–acceptor interactions. Natural bond orbital (NBO) and atoms in molecules (AIM) analyses were used to characterize the weak ionic interactions between the nitrogen and pnictogen atoms. The HOMOs of 1 and 2 correspond to the lone pairs of electrons on the central pnictogen atom, which indicates that these compounds can be classified as 14–Pn–6 chemical species. Fourteen valence electrons: The central pnictogen atom of pseudo‐hexacoordinated pnictines has three covalent bonds, three weak bonds, and a lone pair of electrons, indicating that it has formally fourteen valence electrons. Both X‐ray crystallographic analysis and theoretical calculations suggest that these structures represent 14–Pn–6‐type chemical species.