Air‐Tolerant 1‐Amino‐1, 3‐diphosphacyclobutane‐2, 4‐diyls Featuring Strong Electron‐Donating Properties and Small HOMO–LUMO Gaps. Issue 24 (26th June 2017)

• Record Type: Journal Article
• Authors: Ito, Shigekazu; Ueta, Yasuhiro; Ngo, Trang Thi Thu; Koshino, Kota; Mikami, Koichi
• Is Part Of: European journal of inorganic chemistry. Issue 24(2017)
• Page Start: 3048
• Page End: 3052
• Publication Date: 2017-06-26
• Subjects: Heterocycles -- Phosphorus -- Nitrogen -- Anions -- Radicals; Chemistry, Inorganic -- Periodicals; Organometallic chemistry -- Periodicals; Bioinorganic chemistry -- Periodicals; Solid state chemistry -- Periodicals; 546
• DOI: 10.1002/ejic.201700432
• Languages: English
• ISSNs: 1434-1948

Abstract

Abstract : The sterically encumbered 1‐amino‐1, 3‐diphosphacyclobuten‐4‐yl anion, prepared from 1‐(2, 4, 6‐tri‐ tert ‐butylphenyl)‐2‐phosphaethyne and lithium diisopropylamide (0.5 equiv.), was characterized spectroscopically and afforded air‐tolerant amino‐substituted 1, 3‐diphosphacyclobutane‐2, 4‐diyls by SN 2‐type alkylation and arylation reactions with benzyne. The photoabsorption and electrochemical parameters of the P‐heterocyclic singlet open‐shell compounds revealed that they had higher electron‐donating character than the relevant hydrocarbon‐substituted P‐heterocycles in addition to a reduction between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) levels. The structures of the amino‐substituted 1, 3‐diphosphacyclobutane‐2, 4‐diyls were unambiguously determined by X‐ray crystallography, and the metric parameters were compatible with the physical properties. The successful synthesis and full characterization of the amino‐substituted phosphorus congener of cyclobutane‐1, 3‐diyl will be helpful to develop functional materials based on open‐shell neutral and ionized phosphorus heterocycles. Abstract : Sterically encumbered 1‐amino‐1, 3‐diphosphacyclobutane‐2, 4‐diyls are successfully isolated as air‐tolerant crystalline compounds from the corresponding P‐heterocyclic anion intermediates. The strong electron‐donating character and small HOMO–LUMO gap are compatible with the molecular structures determined by X‐ray crystallography.