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An Isolable Diphosphene Radical Cation Stabilized by Three‐Center Three‐Electron π‐Bonding with Chromium: End‐On versus Side‐On Coordination
Author(s) -
Wang Wenqing,
Xu CongQiao,
Fang Yong,
Zhao Yue,
Li Jun,
Wang Xinping
Publication year - 2018
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201805115
Subject(s) - electron paramagnetic resonance , unpaired electron , delocalized electron , chemistry , crystallography , atom (system on chip) , center (category theory) , chromium , radical ion , ligand (biochemistry) , radical , spectroscopy , photochemistry , nuclear magnetic resonance , ion , physics , organic chemistry , biochemistry , receptor , quantum mechanics , computer science , embedded system
Abstract Two salts ( 2 and 4 ) containing the radical cations of complexed diphosphenes have been isolated and characterized by electron paramagnetic resonance (EPR) spectroscopy, IR spectroscopy, and single‐crystal X‐ray diffraction. The P−P bond is coordinated to the Cr center either in an end‐on (in 2 ) or a side‐on (in 4 ) fashion. The spin density of the radical is delocalized over the Cr atom and the two P atoms in 2 whereas the unpaired electron is mainly localized on the Cr atom in 4 . This work provides the first example of a complexed diphosphene radical ( 2 ) featuring novel three‐center three‐electron (3c‐3e) π‐bonding in the Cr‐P‐P unit, and the first example of a 17 e Cr radical with a side‐on π‐bonded ligand ( 4 ).