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Air‐Tolerant 1‐Amino‐1,3‐diphosphacyclobutane‐2,4‐diyls Featuring Strong Electron‐Donating Properties and Small HOMO–LUMO Gaps
Author(s) -
Ito Shigekazu,
Ueta Yasuhiro,
Ngo Trang Thi Thu,
Koshino Kota,
Mikami Koichi
Publication year - 2017
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201700432
Subject(s) - chemistry , homo/lumo , steric effects , cyclobutane , singlet state , lithium diisopropylamide , molecular orbital , ion , medicinal chemistry , stereochemistry , photochemistry , crystallography , molecule , organic chemistry , ring (chemistry) , physics , deprotonation , nuclear physics , excited state
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 S N 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.