A reaction of 2,5-diphenylphosphacymantrene with diethylamine in the presence of water

Full text of DOI:10.1007/s11172-010-0109-0

Russian Chemical Bulletin, International Edition, Vol. 59, No. 2, pp. 486—487, February, 2010
486
Letters to the Editor
A reaction of 2,5ꢀdiphenylphosphacymantrene with diethylamine
in the presence of water
V. V. Bashilov, A. G. Ginzburg, A. F. Smol´yakov, F. M. Dolgushin, P. V. Petrovskii, and V. I. Sokolov
A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences,
28 ul. Vavilova, 119991 Moscow, Russian Federation.
Fax: +7 (499) 135 5085. Eꢀmail: allan@ineos.ac.ru
Scheme 1
In our continued investigations of the chemistry of
2,5ꢀdiphenylphosphacymantrene (1),1,2 we found that
compound 1 does not react with Et2NH in benzene or
CH2Cl2. However, in the presence of small amounts of
water (amine : water = ~(8—10) : 1), complex 2 forms
slowly (Scheme 1). The transformation 1→2 results in the
following spectral changes: in the 31P NMR spectrum, the
signal for the starting reagent 1 (s, δ –30.6) becomes less
intense and a lowꢀfield doublet (1JP,H = 549 Hz) characꢀ
teristic of a P—H bond appears. Complex 2 is poorly soꢀ
luble in C6H6 and CH2Cl2 and insoluble in pentane
and hexane.
In the IR spectrum of complex 2, both the bands ν(CO)
are shifted to the lower wavenumbers, thus suggesting the
formation of an anion. The ratio of the band widths charꢀ
acteristic of the fragment Mn(CO)3 is retained: in CH2Cl2,
ν(CO) 1950 (br) and 2025 cm–1 for 1 and 1900 (br) and
1990 cm–1 for 2. The 1H{31P} NMR spectrum of complex
2 contains a broadened singlet at δ 7.83 for the P—H
proton, which is absent from the spectrum of the starting
compound 1. According to preliminary Xꢀray diffraction
data, complex 2 has an ionic structure consisting of the
anion [(CO)3Mnꢀηꢀ2,5ꢀPh2H2C4P(=O)H]– and the catꢀ
ion Et2NH2+. It is known that such nucleophiles as OMe,
i. Et2NH, H2O
OEt,2 PhLi,3 and ButLi4 can add to the P atom, which
correlates with quantumꢀchemical calculations.3,5 The
formation of complex 2 can be explained as follows. Apꢀ
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 476—477, February, 2010.
1066ꢀ5285/10/5902ꢀ0486 © 2010 Springer Science+Business Media, Inc.

Hydration of 2,5ꢀdiphenylphosphacymantrene
Russ.Chem.Bull., Int.Ed., Vol. 59, No. 2, February, 2010
487
(DMSOꢀd6), δ: 7.82 (br.s, 1 H, P—H); 7.30, 7.19, 7.00 (10 H
parently, the presence of a strong base (amine) leads to the
equilibrium in solution
each, oꢀ, mꢀ, and pꢀC6H5); 5.51 (d, 2 H, H(3), H(4), 3JH(3,4),P
= 12.7 Hz); 2.81 (br.q, 4 H, N—CH2); 1.09 (t, 6 H, CH3, JH,H
=
=
= 7 Hz). The coupling constant 1J1 P = 549.0 Hz obtained by
Et2NH + H2O
Et2NH2+OH–.
31
H,
comparing the 1H and 1H{31P} NMR spectra is identical with
In a reaction of Et2NH2+OH– with compound 1,
the nucleophile OH– adds to the P atom to give an unstaꢀ
ble intermediate anion containing a P—OH bond (see
Scheme 1). Migration of the H atom from oxygen to
phosphorus results in rapid transformation of the anion
into complex salt 2 containing the phosphoryl fragment
P(=O)H with the P—H bond in the anion.
that determined from the 31P NMR spectrum.
This work was financially supported by the Russian
Foundation for Basic Research (Project No. 08ꢀ03ꢀ00169).
References
1. A. G. Ginzburg, V. V. Bashilov, F. M. Dolgushin, V. I.
Sokolov, Izv. Akad. Nauk, Ser. Khim., 2008, 1995 [Russ. Chem.
Bull., Int. Ed., 2008, 57, 2030].
2. A. G. Ginzburg, V. V. Bashilov, F. M. Dolgushin, A. F.
Smol´yakov, A. S. Peregudov, V. I. Sokolov, J. Organomet.
Chem., 2009, 694, 72.
3. B. Deschamps, P. Toullec, L. Ricard, F. Mathey, J. Orgaꢀ
nomet. Chem., 2001, 634, 131.
4. B. Deschamps, L. Ricard, F. Mathey, J. Organomet. Chem.,
2004, 689, 4647.
1
H and 31P NMR spectra were recorded on a Bruker Avanceꢀ
400 instrument (400.16 (1H) and 161.92 MHz (31P)). Chemical
shifts are referenced to SiMe4 for 1H and to H3PO4 for 31P.
Complex 2. Two to three drops of water were added in an
inert atmosphere to compound 1 (30 mg, 0.08 mmol) in a mixꢀ
ture of diethylamine (1 mL) and CH2Cl2 (3 mL). The reaction
mixture was stirred and left in the dark at room temperature.
After ~24 h, yellow crystals began to form. The solution was
decanted and the crystals were washed with cold pentane two to
three times and dried in vacuo. The yield of complex 2 was 22 mg
(60%). Found (%): C, 59.13; H, 5.45; N, 3.16. C23H25MnNO4P.
Calculated (%): C, 59.36; H, 5.41; N, 3.01. 31P NMR (CH2Cl2),
5. C. Guimon, G. PfisterꢀGuilliouso, F. Mathey, Nouv. J. Chem.,
1979, 3, 725.
1
δ: –8.70 (d, JP,H = 549.0 Hz; the chemical shift refers to the
midpoint of the doublet). Either line of the doublet is split into
Received June 10, 2009;
in revised form August 18, 2009
3
a triplet with the constant JP,H(3,4) = 12.7 Hz. 1H{31P} NMR