ic500274h_si_002.cif (70.78 kB)
N,N′-Fused Bisphosphole: Heteroaromatic Molecule with Two-Coordinate and Formally Divalent Phosphorus. Synthesis, Electronic Structure, and Chemical Properties
dataset
posted on 2014-03-17, 00:00 authored by Alexander N. Kornev, Vyacheslav V. Sushev, Yulia
S. Panova, Olga V. Lukoyanova, Sergey Yu. Ketkov, Evgenii V. Baranov, Georgy K. Fukin, Mikhail A. Lopatin, Yulia G. Budnikova, Gleb A. AbakumovThe reduction of 6,12-dichloro-1,2,3,4,7,8,9,10-octahydro-6H,12H-[1,2,3]benzodiazaphospholo[2,1-a][1,2,3]benzodiazaphosphole (3) by metallic
magnesium in tetrahydrofuran (THF) affords the N,N′-fused bisphosphole 1 in 92% yield. The compound reveals a novel type of 10π-electron
heteroaromatic system [NICS(0) = −11.4], containing a two-coordinate
and formally divalent phosphorus atom. Compound 1 possesses
a much higher coordination activity than many other diazaphospholes.
This is caused by a novel type of complexation to a metal ion wherein
the lone phosphorus pairs are not involved in metal coordination.
Instead, the 10π-electron heteroaromatic system provides two
electrons for P → M bond formation. Polarization of the ligand
results in the formation of extended molecular associates or cluster
compounds. Complexes of 1 with mercury dichloride [{(1)3HgCl}2(μ6-Cl)]+Cl– (7) and tin dichlorides
[1·SnCl2(PhMe solvate)] (8a) and [1·SnCl2] (8b) are,
in fact, supramolecular in nature, containing multiple intermolecular
short contacts. Crystals of complex 8a containing short
Sn···Sn packing interactions were converted reversibly
to metallic tin after workup with THF. The simple mixing of 1 and 3 (1:1) gave a P–P bridging dimeric
species prone to easy dissociation. The addition of GeCl2(diox) to the equimolar mixture of 1 and 3 shifted the equilibrium to the formation of a poorly soluble salt-like
dimer 6, which is, in fact, a stacked 18π-electron
dication having a through-space delocalization of π electrons.