Electron-donating ability of triarylphosphines and related compounds studied by 31P NMR spectroscopy

Article abstract of DOI:10.1023/A:1022483912466

The influence of aryl, heterocyclic, amide, alkyl, alkoxyl, thioalkoxyl, and ferrocenyl substituents at the phosphorus atom on its electron-donating ability was studied by the measurement of direct ³¹P-⁷⁷Se spin-spin coupling constants for the corresponding selenides. Series of diphenylorganylphosphines and their selenides were studied.

Full text of DOI:10.1023/A:1022483912466

78
Russian Chemical Bulletin, International Edition, Vol. 52, No. 1, pp. 78—84, January, 2003
Electronꢀdonating ability of triarylphosphines and related compounds
studied by 31Р NMR spectroscopy
c
b
a
M. N. Chevykalova,a,b L. F. Manzhukova, N. V. Artemova, Yu. N. Luzikov,
ꢀ
I. E. Nifant´ev,a and E. E. Nifant´evb
aDepartment of Chemistry, M. V. Lomonosov Moscow State University,
Leninskie Gory, 119992 Moscow, Russian Federation.
Fax: +7 (095) 939 4523. Eꢀmail: inif@org.chem.msu.ru
bDepartment of Chemistry, V. I. Lenin Moscow Pedagogical State University,
3 Nesvizhskii per., 119021 Moscow, Russian Federation.
Fax: +7 (095) 246 7766, 248 0162. Eꢀmail: chemfak@centro.ru
cDepartment of Chemistry, Chelyabinsk State Pedagogical University,
454080 Chelyabinsk, 69, Russian Federation.
Fax: +7 (351 2) 36 7753. Eꢀmail: cs@spi.urc.ac.ru
The influence of aryl, heterocyclic, amide, alkyl, alkoxyl, thioalkoxyl, and ferrocenyl
substituents at the phosphorus atom on its electronꢀdonating ability was studied by the meaꢀ
surement of direct 31P—77Se spinꢀspin coupling constants for the corresponding selenides.
Series of diphenylorganylphosphines and their selenides were studied.
Key words: phosphineselenides, 31P—77Se spinꢀspin coupling constants, heteroarylꢀ
phosphines.
Tertiary phosphines are widely used for preparation of
ferrocenyl, amido, alkoxy, or thio fragment instead of one
Ph group. The indole, imidazole, or thiophene residues
were used as heterocyclic substituents. Diphenylorganylꢀ
phosphines 12, 13, and 16—19 were synthesized by the
reactions of the corresponding magnesium or lithium salts
with Ph2PCl. On boiling with selenium in chloroform,6
compounds 12, 13, and 16—19 were transformed into the
corresponding selenides (Scheme 1).
transition metal complexes employed as catalysts in hoꢀ
mogeneous catalysis. The influence of phosphine ligands
on the properties and reactivity of metal complexes was
established to be mainly determined by electronic and
steric effects. Several reviews1—3 are devoted to the influꢀ
ence of steric factors, whereas electronic effects are poorly
studied. To estimate the electronꢀdonating ability of phosꢀ
phine ligands, researchers use frequencies of stretching
vibrations ν(СО) of coordinated CO in monosubstituted
transition metal carbonylphosphines,4,5 direct 31P—195Pt
spinꢀspin coupling constants (SSC) of the platinum phosꢀ
phine complexes,6,7 and direct 31P—77Se SSC constants
of the corresponding selenephosphines.6 In our opinion,
the latter is most available among the listed approaches.
Scheme 1
1
According to the studies,6 the JP,Se values for seꢀ
lenides depend on the nature of substituents at the P
atom: electronꢀwithdrawing groups increase and electronꢀ
donating groups decrease this parameter. Note that these
regularities were observed6 for the restricted number of
phosphine samples. Since search for new ligands is an
urgent problem, it seemed of interest to extend the scope
of studied organophosphorus compounds and to study
more specifically how the substituent nature affects a
change in the electronꢀdonating ability of the P atom
(Table 1).
Compound
R
Yield (%)
12
13
16
17
18
19
2ꢀMethylꢀ5ꢀthienyl
2ꢀMethylꢀ4ꢀthienyl
NꢀMethylindolyl
NꢀPhenylindolyl
NꢀMethylimidazolyl
NꢀPhenylimidazolyl
92
61
74
54
33
27
We synthesized a group of compounds related to Ph3P,
whose molecules contained the heterocyclic, aryl, alkyl,
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 75—80, January, 2003.
1066ꢀ5285/03/5201ꢀ78 $25.00 © 2003 Plenum Publishing Corporation

Electronꢀdonating ability of Ph2PR
Russ.Chem.Bull., Int.Ed., Vol. 52, No. 1, January, 2003
79
Table 1. 31Р NMR spectroscopic data for organophosphorus compounds Ph2PR 1—21 and their selenides Ph2P(Se)R 1a—21a
(CDCl3)
1
a
1
a
Ph2PR
δ
1JP,Se ∆ JP,Se
Ph2PR
δ, м.д.
1JP,Se ∆ JP,Se
Ph2PR Ph2P(Se)R
Hz
Ph2PR Ph2P(Se)R
Гц
Ph3P (1)
–8.0
32.6
730
—
(14) –26.6 b
16.9 b
17.5 b
754 b
728 b
24
–4.7 b
–8.0 c
35.9 b
732 b
(15) –29.7 b
–2
(2)
–8.8
32.1
726
–4
0
(3)
(4)
–13 b
32.6 b
730 b
(16) –30.7
(17) –30.7
16.3
17.2
731
747
1
–9.3
–43.1
–6.3
31.6
54.0
42.8
64.6
63.7
734
717
726
747
748
4
–13
–4
17
ButPPh2 (5)
(6)
(8)
(18) –33.2
(19) –32.0
(20) –19.2
15.4
16.6
29.1
737
754
732
7
24
2
Ph2PNEt2 (7)
59.0
17
44.8 d
18
ButSPPh2 (9)
Ph2POEt (10)
—
108.4
39.2
81.7
772
796
42
66
(11) –19.3 b
(12) –21.9
20.6 b
743 b
13
3
19.3
733
(21) –19.8
28.2
737
7
(13) –20.2
20.3
728
–2
a Difference of the 31P—77Se SSC constants for Ph2P(Se)R and Ph3PSe.
b See Ref. 6.
c See Ref. 8.
d C6D6 is solvent.
Organophosphorus compounds containing ferrocenyl
alkyl, amino, alkoxy, or thio group and their selenides
were synthesized using standard procedures. The data of
31Р NMR spectroscopy for the synthesized selenides and
published data6,8 are presented in Table 1.
benzene ring was modified, the detected changes in the
constant turned out small.
The replacement of one Ph group in the Ph3P molꢀ
ecule by the amido, alkoxy, or thio group enhances the
electronꢀwithdrawing ability of the phosphine. The highꢀ
est constant is observed in the case of alkoxy group introꢀ
duction, which is due to a higher electronegativity of the
O atom than those of N and S. On going from thioꢀ to
amidophosphines, 1JP,Se decreases, and the constant value
is independent of the amino group structure.
The influence of a substituent was qualitatively evaluꢀ
1
ated by comparison of the JP,Se values for the studied
compounds and Ph3P (direct 31P—77Se SSC constants for
all considered compounds are positive). The following
conclusions were made.
The introduction of the Me group into both the
orthoꢀ and paraꢀpositions of the Ph ring increases the
electronꢀdonating ability of phosphine. The appearance
of the F atom in the paraꢀposition of the Ph ring makes
the phosphine more electronꢀwithdrawing than Ph3P:
1JP,Se for рꢀFC6H4P(Se)Ph2 is 734, and that for Ph3PSe
is 730. However, it should be mentioned that when the
Special attention should be given to the results for
phosphines containing the heterocyclic fragment. It has
previously been mentioned9 that ligands containing elecꢀ
tronꢀwithdrawing substituents dissociate from the metalꢀ
lic center more easily to favor the acceleration of the
catalytic reaction. Among all heteroarylphosphines preꢀ
sented in Table 1, compounds 14 and 19 are most elecꢀ

80
Russ.Chem.Bull., Int.Ed., Vol. 52, No. 1, January, 2003
Chevykalova et al.
1
tion dependences of JP,Se for selenide were not studied. The
element composition of all compounds was determined using an
automated Carlo—Erba analyzer at the MONTELL Research
Center (Ferrara, Italy).
tronꢀwithdrawing. Phosphines with nitrogenꢀcontaining
heterocycles are characterized by the following regularities:
all nitrogen heteroarylphosphines, except for Nꢀmethylꢀ
pyrrole heteroarylphosphine, are less electronꢀdonating
than Ph3P; the replacement of the methyl group at the
N atom by the phenyl group increases the electronꢀwithꢀ
drawing ability of the phosphine (for the indole and imiꢀ
dazole derivatives, the direct 31P—77Se SSC constant inꢀ
creases by 16 and 17 Hz, respectively); the electronꢀwithꢀ
drawing ability of phosphines decreases in the series imiꢀ
dazolyl > indolyl > pyrrolyl. Comparing heteroarylꢀ
phosphines containing the thiophene fragment (11—13),
one can note the following: 3ꢀthienyl groups are less elecꢀ
tronꢀwithdrawing than their 2ꢀisomers; introduction of
the Me substituent into position 5 of the thiophene ring
(compound 12) makes phosphine less electronꢀwithdrawꢀ
2ꢀMethylꢀ5ꢀbromothiophene,11 2ꢀmethylꢀ4ꢀbromothioꢀ
phene,12,13 Nꢀmethylindole,14 Nꢀphenylindole,15 and Nꢀphenylꢀ
imidazole15 were synthesized using known procedures. pꢀTolylꢀ
diphenylphosphine (2),16 (4ꢀfluorophenyl)diphenylphosphine (4),17
tertꢀbutyldiphenylphosphine (5),18 cyclohexyldiphenylphosꢀ
phine (6),19 N,Nꢀdiethyl(diphenyl)phosphinamide (7),20
ethyl(diphenyl) phosphinite (10),20 ferrocenyldiphenylphosphine
(20),21 and 1,1´ꢀbis(diphenylphosphino)ferrocene (21)22 were synꢀ
thesized using standard methods.
1ꢀ(Diphenylphosphino)pyrrolidine (8) was synthesized simiꢀ
larly to compound 7 20 from pyrrolidine (3.8 mL, 0.045 mol),
Et3N (6.3 mL, 0.045 mol), Et2O (200 mL), and Ph2PCl (8.1 mL,
0.045 mol). The product was obtained in 48% yield (5.53 g) as a
colorless liquid, b.p. 142 °C (0.6 Torr). Found (%): С, 75.23;
Н, 7.21; N, 5.38. C16H18PN. Calculated (%): С, 75.27; Н, 7.11;
N, 5.49. 1Н NMR (C6D6), δ: 2.50—2.60, 3.00—3.10 (both m,
4 Н each, СН2); 7.15—7.30 (m, 6 Н, СН=, Ph); 7.50—7.60 (m,
4 Н, СН=, Ph).
1
ing, which is reflected as a decrease in JP,Se of selenide;
diphenylphosphino group in position 3 facilitates thienylꢀ
phosphine (compound 13) to become even more elecꢀ
tronꢀdonating than Ph3P.
tertꢀButylthio(diphenyl)phosphine (9) was synthesized simiꢀ
larly to compound 7 20 from HSBut (5.1 mL, 0.045 mol), Et3N
(6.3 mL, 0.045 mol), Et2O (200 mL), and Ph2PCl (8.1 mL,
0.045 mol). Due to its easy hydrolyzability and oxidizability, the
product was used for the synthesis of selenide without additional
purification.
The introduction of the ferrocenyl substituent makes
phosphine slightly more electronꢀwithdrawing than Ph3P
(1JP,Se of selenide 20 differs from the direct constant in
Ph3PSe by 2 Hz only). The appearance of the diphenylꢀ
phosphino group in the second ring of ferrocene increases
1JP,Se of the corresponding selenide.
(2ꢀMethylꢀ5ꢀthienyl)diphenylphosphine (12). A solution of
Ph2PCl (3 mL, 0.02 mol) in THF (5 mL) was added on cooling
to –40 °С to a solution of 2ꢀmethylꢀ5ꢀthienylmagnesium broꢀ
mide prepared from Mg (0.45 g, 0.019 mol), dibromoethane
(0.15 mL, 0.0017 mol), and 5ꢀbromoꢀ2ꢀmethylthiophene (3 g,
0.017 mol) in THF (20 mL). The reaction mixture was stirred
for 12 h at ∼20 °С, then water was added (10 mL), the organic
layer was separated, and the aqueous layer was extracted with
Et2O (3×10 mL). The combined organic fractions were washed
with water and dried above MgSO4; the solvents were removed
at reduced pressure. The obtained yellow oil was purified by
column chromatography (silica gel 60, benzene—AcOEt, 4 : 1).
The solvents were removed at reduced pressure. Compound 12
was obtained in 92% yield (4.41 g) as a yellowish oil, which crysꢀ
tallized during prolonged storage, m.p. 49—50 °С. Found (%):
С, 72.15; Н, 5.41. C17H15PS. Calculated (%): С, 72.32; Н, 5.35.
1Н NMR (CDCl3), δ: 2.55 (s, 3 Н, Ме); 6.86 (m, 1 Н, СН= of
thiophene ring; 7.26 (dd, 1 Н, СН= of thiophene ring, J =
3.4 Hz, J = 6.7 Hz); 7.40—7.44, 7.47—7.52 (both m, 10 Н, Ph).
(2ꢀMethylꢀ4ꢀthienyl)diphenylphosphine (13) was synthesized
similarly to compound 12 from Mg (1.49 g, 0.062 mol),
dibromoethane (0.5 mL, 0.0057 mol), 4ꢀbromoꢀ2ꢀmethylꢀ
thiophene (10 g, 0.057 mol), THF (70 mL), and Ph2PCl
(12.2 mL, 0.068 mol). The product was obtained in 61% yield
(9.73 g) as a yellowish oil. Found (%): С, 72.18; Н, 5.19.
C17H15PS. Calculated (%): С, 72.32; Н, 5.35. 1Н NMR
(CDCl3), δ: 2.55 (d, 3 Н, Ме, J = 1.1 Hz); 6.79 (m, 1 Н,
CH= of thiophene ring), 7.09 (dd, 1 Н, CH= of thiophene ring,
J = 1.4 Hz, J = 4.7 Hz); 7.40—7.51 (m, 10 Н, Ph).
The replacement of the Ph group in Ph3P by a satuꢀ
rated hydrocarbon radical substantially changes the elecꢀ
tronic properties of phosphine. For example, the introꢀ
duction of the tertꢀbutyl or cyclohexyl group favors an
increase in the electronꢀdonating ability of phosphine,
which is reflected as a decrease in the direct 31P—77Se
SSC constant of selenide. This fact agrees completely
with previous results.6
Thus, we can conclude that the electronꢀdonating abilꢀ
ity of tertiary phosphines can substantially be varied due
to a change in heterocyclic radicals in molecules of these
compounds.
Experimental
All experiments were carried out in argon. Solvents were
purified as follows10: ethereal solvents were stored and distilled
over КОН and then over sodium benzophenone ketyl; СНСl3
was washed with water, concentrated H2SO4, and water to neuꢀ
tral reaction, dried over CaCl2, and distilled over Р2О5; benzene
was dried by refluxing and distillation over sodium. Commercial
reagents available from Lancaster, Merck, and Fluka were used.
1Н, 31Р, and 13С NMR spectra were recorded on a Varian
VXRꢀ400 instrument. For measurements of δ of organophosꢀ
Р
phorus compounds and their selenides, 70% H3PO4 was used as
external standard (a sealed capillary was immersed in a solution
1
and centered). The measurement of JP,Se was carried out at
(NꢀMethylꢀ2ꢀindolyl)diphenylphosphine (16). A 1.6 М soluꢀ
tion of BunLi in hexane (11.1 mL, 0.018 mol) was added on
cooling to –70 °С to a solution of Nꢀmethylindole (2.2 g,
0.017 mol) and TMEDA (2.7 mL, 0.018 mol) in Et2O (15 mL).
20 °С ( 1—2 °С). The accuracy of measurement of the direct
31P—77Se SSC constant was 0.5 Hz. The reproducibility of
results was sufficiently high. The temperature and concentraꢀ

Electronꢀdonating ability of Ph2PR
Russ.Chem.Bull., Int.Ed., Vol. 52, No. 1, January, 2003
81
The reaction mixture was stirred for 4 h at ∼20 °С, cooled to
–40 °С, and a solution of Ph2PCl (3.2 mL, 0.018 mol) in Et2O
(5 mL) was added dropwise. Cooling was stopped, and the reacꢀ
tion mixture was left for stirring for 12 h. Water (10 mL) was
added to the mixture, the organic layer was separated, and the
aqueous layer was extracted with Et2O (3×10 mL). The comꢀ
bined organic fractions were washed with water (2×10 mL) and
dried above MgSO4; the solvents were removed at reduced presꢀ
sure. The solid residue was purified by column chromatography
(silica gel 60, benzene), and the solvent was evaporated at reꢀ
duced pressure. The product was obtained in 74% yield (4 g) as a
white crystalline substance, m.p. 120—122 °С. Found (%):
С, 80.10; Н, 5.70; N, 4.36. C21H18NP. Calculated (%): С, 79.98;
(NꢀMethylꢀ2ꢀimidazolyl)diphenylphosphine (18). A 1.6 М soꢀ
lution of BunLi in hexane (10 mL, 0.016 mol) was added on
cooling to –70 °C to a solution of Nꢀmethylimidazole (1.25 g,
0.015 mol) and TMEDA (2.4 mL, 0.016 mol) in Et2O (12 mL).
The reaction mixture was stirred for 4 h at ∼20 °C, cooled to
–40 °C, and added by a solution of Ph2PCl (2.9 mL, 0.016 mol)
in Et2O (5 mL). Cooling was stopped, the reaction mixture was
left for stirring for 12 h, and water (10 mL) was added to the
mixture. The organic layer was separated, and the aqueous layer
was extracted with Et2O (3×10 mL). The combined organic
fractions were washed with water (2×10 mL) and dried above
MgSO4; solvents were removed at reduced pressure. The solid
residue was purified by column chromatography (silica gel 60,
benzene—AcOEt (4 : 1 — I fraction, 1 : 1 — II fraction)). All
solvents were removed under reduced pressure. Fraction II conꢀ
tained compound 18. The product was obtained in 33% yield
(1.36 g) as a white crystalline substance, m.p. 73 °C. Found (%):
С, 72.05; Н, 5.73; N, 10.39. C16H15N2P. Calculated (%):
С, 72.17; Н, 5.68; N, 10.52. 1Н NMR (CDCl3), δ: 3.80 (s, 3 Н,
Ме); 7.11 (m, 1 Н, CH= of imidazole ring); 7.35 (br.s, 1 Н,
CH= of imidazole ring); 7.42—7.46 (m, 6 Н, CH=, Ph);
7.53—7.58 (m, 4 Н, CH=, Ph).
1
Н, 5.75; N, 4.44. Н NMR (CDCl3), δ: 3.70 (s, 3 Н, Ме); 6.14
(s, 1 Н, CH= of indole ring); 7.08 (t, 1 Н, CH=, Ar, J =
8.0 Hz); 7.21 (m, 1 Н, CH=, Ar); 7.29—7.41 (m, 11 Н, CH=,
Ar); 7.51 (d, 1 Н, CH=, Ar, J = 10.0 Hz).
(NꢀPhenylꢀ2ꢀindolyl)diphenylphosphine (17) was syntheꢀ
sized similarly to compound 16 from Nꢀphenylindole (1.34 g,
6.95 mmol), TMEDA (1.1 mL, 7.3 mmol), a 1.6 М solution
of BunLi in hexane (4.6 mL, 7.3 mmol), Ph2PCl (1.4 mL,
7.7 mmol), and Et2O (15 mL). The precipitate, which was formed
after water (10 mL) was added to the reaction mixture, was
filtered off, washed with water (3×10 mL) and hexane (15 mL),
and dried in high vacuum. The product was obtained in 54%
(1.42 g) as a white crystalline substance, m.p. 183—184 °C.
Found (%): С, 82.83; Н, 5.40; N, 3.62. C26H20NP. Calcuꢀ
lated (%): С, 82.74; Н, 5.34; N, 3.71. 1Н NMR (CDCl3), δ: 6.38
(s, 1 Н, CH= of indole ring); 7.16—7.22, 7.26—7.30, 7.36—7.44,
7.60—7.62 (all m, 19 Н, CH=, Ar).
(NꢀPhenylꢀ2ꢀimidazolyl)diphenylphosphine (19) was syntheꢀ
sized similarly to compound 18 from Nꢀphenylimidazole (2 g,
0.014 mol), TMEDA (2.2 mL, 0.015 mol), a 1.6 М solution of
BunLi in hexane (9.1 mL, 0.015 mol), Ph2PCl (2.6 mL,
0.015 mol), and Et2O (25 mL). The precipitate, formed after
water (10 mL) was added to the reaction mixture, was filtered
off, washed with water (3×10 mL) and Et2O (20 mL), dried in
high vacuum, and purified by column chromatography (silica
Table 2. 13C NMR spectroscopic data for organophosphorus compounds Ph2PR 8, 12, 13, and 16—19 (CDCl3)
Comꢀ
pound
R
δ (J/Hz)
Ph2P
R
8
Pyrrolidyl*
128.36 (СН=, J = 5.7); 128.43, 132.49 (СН=,
J = 19.5); 139.96 (=С<, J = 14.3)
26.46 (СН2, J = 5.3); 49.81 (СН2,
J = 13.0)
12
2ꢀMethylꢀ5ꢀthienyl
2ꢀMethylꢀ4ꢀthienyl
NꢀMethylꢀ2ꢀindolyl
128.17 (СН=, J = 7.0); 128.48, 132.78 (СН=,
J = 19.4); 138.10 (=С<, J = 8.3)
15.36 (Me); 126.25 (СН=, J = 8.7);
134.96 (=С<, J = 27.0); 136.83 (СН=,
J = 28.9); 147.06 (=С<)
13
16
128.25 (СН=, J = 6.9); 128.45, 133.12 (СН=,
J = 19.5); 137.56 (=С<, J = 9.9)
15.03 (Me); 129.07 (СН=, J = 17.0);
129.52 (СН=, J = 23.1); 136.23 (=С<,
J = 13.1); 140.93 (=С<, J = 6.2)
31.02 (Me, J = 13.7); 108.99 (СН=,
J = 2.0); 110.36 (СН=, J = 2.5); 119.40,
120.46, 121.96 (СН=); 127.80 (=С<,
J = 2.5); 136.97 (=С<, J = 3.6); 139.83
(=С<, J = 2.6)
128.48 (СН=, J = 7.0); 128.96, 133.59 (СН=,
J = 19.8); 135.20 (=С<, J = 6.9)
17
NꢀPhenylꢀ2ꢀindolyl
128.29 (СН=, J = 7.3); 128.85 (СН=,
J = 2.5); 133.78 (СН=, J = 20.5); 135.75
(=С<, J = 7.5)
110.40, 111.90, 120.14, 120.41, 122.53,
127.81 (СН=); 127.94 (=С<); 128.26,
128.41 (СН=, J = 2.7); 137.95, 138.46
(=С<, J = 5.3); 140.60 (=С<)
33.67 (Me, J = 14.2); 123.35, 130.70
(CH=, J = 3.0); 145.54 (=С<)
123.60, 126.17 (СН=, J = 3.7); 128.30,
128.84, 131.19 (СН=); 137.78, 146.52
(=C<, J = 7.0)
18
19
NꢀMethylꢀ2ꢀimidazolyl
NꢀPhenylꢀ2ꢀimidazolyl
128.27 (СН=, J = 7.7); 128.81, 133.44 (СН=,
J = 20.3); 134.72 (=С<, J = 4.2)
128.26 (СН=, J = 7.6); 128.84, 133.69 (СН=,
J = 20.7); 135.43 (=С<, J = 5.3)
* C6D6 was used as the solvent.

82
Russ.Chem.Bull., Int.Ed., Vol. 52, No. 1, January, 2003
Chevykalova et al.
gel 60, benzene—AcOEt, 1 : 1). The solvents were removed at
reduced pressure. The product was obtained in 27% (1.25 g) as a
white finely crystalline substance, m.p. 124—125 °C. Found (%):
С, 76.92; Н, 5.84; N, 8.42. C21H17N2P. Calculated (%):
С, 76.82; Н, 5.22; N, 8.53. 1Н NMR (CDCl3), δ: 7.28—7.31,
7.32—7.33, 7.38—7.42, 7.43—7.47, 7.50—7.56 (all m, 17 Н,
CH= of imidazole ring, Ph).
Selenide 7a. White crystalline substance, m.p. 88—89 °C.
Found (%): С, 57.02; H, 5.95; N, 4.28. C16H20NPSe. Calcuꢀ
lated (%): С, 57.15; H, 5.99; N, 4.17. 1Н NMR (CDCl3), δ: 1.15
(t, 6 H, Ме, J = 9.2 Hz); 3.04—3.13 (qd, 4 H, СН2, J = 12.3 Hz,
J = ∼1 Hz); 7.46—7.54 (m, 6 Н, CH=, Ph); 8.04—8.12 (m, 4 Н,
CH=, Ph).
Selenide 8a. White crystalline substance, m.p. 137—139 °C.
Found (%): С, 57.54; H, 5.57; N, 4.09. C16H18NPSe. Calcuꢀ
lated (%): С, 57.49; H, 5.43; N, 4.19. 1Н NMR (CDCl3), δ:
1.90—2.00, 2.95—3.05 (both m, 4 H each, СН2); 7.44—7.52 (m,
6 Н, CH=, Ph); 8.11—8.18 (m, 4 Н, CH=, Ph).
Selenide 9a. The product was purified by column chromaꢀ
tography (silica gel 60, benzene). Orange crystalline substance,
m.p. 73—75 °C. Found (%): С, 54.43; H, 5.51. C16H19PSSe.
Calculated (%): С, 54.39; H, 5.42. 1Н NMR (CDCl3), δ: 1.60
(s, 9 H, Ме); 7.45—7.55 (m, 6 Н, CH=, Ph); 8.05—8.15 (m,
4 Н, CH=, Ph).
Selenide 10a. Colorless oil. Found (%): С, 54.29; H, 4.95;
О, 5.01. C14H15OPSe. Calculated (%): С, 54.38; H, 4.89;
О, 5.17. 1Н NMR (CDCl3), δ: 1.90 (t, 3 H, Ме, J = 7.1 Hz);
4.13—4.21 (qd, 2 H, СН2, J = 9.1 Hz, J ≈ 1 Hz); 7.46—7.56 (m,
6 Н, CH=, Ph); 7.92—7.99 (m, 4 Н, CH=, Ph).
Selenide 12a. White crystalline substance, m.p. 128 °C.
Found (%): С, 56.61; H, 4.12. C17H15PSSe. Calculated (%):
С, 56.51; H, 4.18. 1Н NMR (CDCl3), δ: 2.56 (s, 3 H, Ме); 6.90
(m, 1 Н, CH= of thiophene ring); 7.32 (dd, 1 H, CH= of
thiophene ring, J = 3.7 Hz, J = 8.8 Hz); 7.46—7.58 (m, 6 Н,
CH=, Ph); 7.80—7.86 (m, 4 Н, CH=, Ph).
Selenide 13a. White crystalline substance, m.p. 161 °C.
Found (%): С, 56.64; H, 4.21. C17H15PSSe. Calculated (%):
С, 56.51; H, 4.18. 1Н NMR (CDCl3), δ: 2.51 (s, 3 H, Ме); 7.02
(d, 1 H, CH= of thiophene ring, J = 3.6 Hz); 7.42 (d, 1 H,
CH= of thiophene ring, J = 9.1 Hz); 7.46—7.56 (m, 6 Н, CH=,
Ph); 7.76—7.84 (dd, 4 Н, CH=, Ph, J = 8.0 Hz, J = 16.0 Hz).
Selenide 16a. White crystalline substance, m.p. 176 °C.
Found (%): С, 64.05; H, 4.51; N, 3.69. C21H18NPSe. Calcuꢀ
lated (%): С, 63.97; H, 4.60; N, 3.55. 1Н NMR (CDCl3), δ: 3.93
(s, 3 H, Ме); 6.28 (d, 1 H, CH= of indole ring, J = 4.7 Hz); 7.20
(t, 1 H, CH=, Ar, J = 8.0 Hz); 7.36—7.44 (m, 2 Н, CH=, Ar);
7.52—7.64 (m, 7 Н, CH=, Ar); 7.90—7.98 (m, 4 Н, CH=, Ar).
The 13С NMR spectra of the above organophosphorus comꢀ
pounds are presented in Table 2.
Synthesis of selenides was carried out using a known proceꢀ
dure.6 A solution of an organophosphorus compound (0.001 mol)
in CHCl3 (for 1, 2, 4—6, 12, 13, and 16—21) or in benzene
(for 7—10) was boiled with selenium (0.3 g, 3.8 mmol) for 5 h. A
selenium excess was filtered off, and the solvent was removed at
reduced pressure. The yields were 98—99%. The characteristics
of the synthesized selenides are presented below.
Selenide 2a. White crystalline substance, m.p. 150 °C.
Found (%): С, 64.14; Н, 4.89. C19H17PSe. Calculated (%):
С, 64.23; Н, 4.82. 1Н NMR (CDCl3), δ: 2.44 (s, 3 Н, Ме); 7.29
(dd, 2 Н, CH=, Ar, J = 2.8 Hz, J = 8.4 Hz); 7.44—7.55 (m, 6 Н,
CH=, Ar); 7.62—7.69 (dd, 2 Н, CH=, Ar, J = 8.0 Hz, J = 13.5
Hz); 7.73—7.80 (dd, 4 Н, CH=, Ar, J = 7.5 Hz, J = 13.6 Hz).
Selenide 4a. White crystalline substance, m.p. 137—139 °C.
Found (%): С, 60.24; Н, 4.02. C18H14FPSe. Calculated (%):
С, 60.18; Н, 3.93. 1Н NMR (CDCl3), δ: 7.14—7.20 (td, 2 Н,
CH=, Ar, J = 4.0 Hz, J = 10.0 Hz); 7.46—7.58 (m, 6 Н, CH=,
Ar); 7.72—7.82 (m, 6 Н, CH=, Ar).
Selenide 5a. The product was purified by column chromaꢀ
tography (silica gel 60, benzene). Light yellow crystalline subꢀ
stance, m.p. 66 °C. Found (%): С, 59.71; Н, 6.09. C16H19PSe.
Calculated (%): С, 59.82; Н, 5.96. 1Н NMR (CDCl3), δ: 2.40
(d, 9 H, Ме, J = 17 Hz); 7.45—7.55 (m, 6 Н, CH=, Ph);
8.01—8.08 (m, 4 Н, CH=, Ph).
Selenide 6a. White crystalline substance, m.p. 138—139 °C.
Found (%): С, 62.39; H, 6.04. C18H21PSe. Calculated (%):
С, 62.25; H, 6.09. 1Н NMR (CDCl3), δ: 1.20—1.40 (m, 3 Н,
cycloꢀC6H11); 1.60—1.80 (m, 5 Н, cycloꢀC6H11); 1.80—1.90
(m, 2 Н, СН2, cycloꢀC6H11); 2.60—2.70 (m, 1 H, СН<,
cycloꢀC6H11); 7.40—7.60 (m, 6 Н, CH=, Ph); 7.90—8.10 (m,
4 Н, CH=, Ph).
Table 3. 13C NMR spectroscopic data for selenides Ph2P(Se)R 2a, 4a, 5a—10a, 12a, 13a, and 16a—21a (CDCl3)
Comꢀ
pound
R
δ (J/Hz)
Ph2P(Se)
R
2a
4a
pꢀTolyl
128.30 (СН=, J = 12.7); 131.32 (J = 2.9);
131.91 (=С<, J = 77.0); 132.41 (СН=,
J = 10.7)
128.42 (СН=, J = 12.7); 131.47 (=С<,
J = 77.5); 131.53 (CH=, J = 2.8); 132.32
(CH=, J = 10.7)
21.29 (Me); 128.10 (=С<, J = 79.0);
129.12 (СН=, J = 13.0); 132.53 (СН=,
J = 10.8); 142.02 (=С<, J = 3.0)
115.59 (dd, СН=, J = 13.9, J = 21.7);
127.50 (dd, =С<, J = 2.9, J = 79.4);
134.92 (dd, СН=, J = 8.8, J = 12.6);
164.58 (dd, =С<, J = 3.2, J = 254.1)
26.42 (Me); 35.43 (>С<, J = 42.1)
4ꢀFluorophenyl
5a
6a
tertꢀButyl
127.90 (СН=, J = 11.3); 129.79 (=С<,
J = 65.6); 131.00 (СН=, J = 2.6); 133.25
(СН=, J = 9.1)
128.28 (СН=, J = 11.5); 129.96 (=С<,
J = 68.7); 131.11 (СН=, J = 2.6); 131.88
(СН=, J = 9.7)
Cyclohexyl
25.42, 25.79, 25.96 (СН2); 37.46 (>CH,
J = 48.0)
(to be continued)

Electronꢀdonating ability of Ph2PR
Russ.Chem.Bull., Int.Ed., Vol. 52, No. 1, January, 2003
83
Table 3 (continued)
Comꢀ
pound
R
δ (J/Hz)
Ph2P(Se)
R
7a
Diethylamino
Pyrrolidyl
128.04 (СН=, J = 12.7); 131.35 (СН=,
J = 2.9); 132.09 (СН=, J = 11.0); 132.98
(=С<, J = 92.3)
128.08 (СН=, J = 12.6); 131.41 (СН=,
J = 2.9); 131.99 (СН=, J = 11.0); 132.85
(=С<, J = 93.4)
13.27 (J = 5.9) (Me); 41.04 (СН2,
J = 3.1)
8a
25.88 (CH2, J = 8.1); 47.65 (CH2,
J = 2.1)
9a
tertꢀButylthio
Ethoxy
128.12 (СН=, J = 13.2); 131.36 (СН=,
J = 3.2); 131.79 (СН=, J = 11.2); 134.20
(=С<, J = 74.1)
128.07 (СН=, J = 13.5); 130.89 (СН=,
J = 11.9); 131.57 (СН=, J = 2.5); 134.57
(=С<, J = 98.2)
128.28 (СН=, J = 13.0); 131.50 (СН=,
J = 2.9); 131.91 (СН=, J = 11.5); 132.56
(=С<, J = 80.8)
128.31 (СН=, J = 12.8); 131.41 (СН=,
J = 2.7); 131.93 (=С<, J = 78.6); 132.01
(СН=, J = 11.1)
32.22 (J = 4.3) (Me); 53.79 (>C<,
J = 4.0)
10a
12a
13a
16a
15.80 (J = 8.4) (Me); 61.99 (CH2,
J = 5.3)
2ꢀMethylꢀ5ꢀthienyl
2ꢀMethylꢀ4ꢀthienyl
NꢀMethylꢀ2ꢀindolyl
15.41 (Me); 126.81 (СН=, J = 13.1);
130.54 (=С<, J = 86.6); 137.94 (СН=,
J = 9.2); 150.17 (=С<, J = 4.2)
15.09 (Me); 127.52 (СН=, J = 15.3);
132.05 (=С<, J = 80.5); 133.23 (СН=,
J = 13.7); 142.46 (=С<, J = 14.7)
32.35 (Me); 109.59, 113.76 (CH=,
J = 13.7); 120.26, 121.56, 124.15 (СН=);
125.98 (=С<, J = 12.6); 127.91 (=С<,
J = 92.2); 141.08 (=С<, J = 7.4)
128.44 (СН=, J = 13.0); 130.37 (=С<,
J = 80.3); 131.82 (СН=, J = 2.9); 132.48
(СН=, J = 11.4)
17a
NꢀPhenylꢀ2ꢀindolyl
128.27 (СН=, J = 7.9); 130.67 (=С<,
J = 80.8); 131.53 (СН=, J = 2.8); 132.76
(СН=, J = 11.1)
111.03, 115.67 (СН=, J = 13.7); 120.90,
121.37, 124.59 (СН=); 125.82 (=С<,
J = 12.4); 128.10, 128.23 (СН=); 129.49
(=С<, J = 93.7); 129.67 (СН=); 136.71,
142.42 (=С<, J = 6.6)
18a
19a
20a
21a
NꢀMethylꢀ2ꢀimidazolyl
NꢀPhenylꢀ2ꢀimidazolyl
Ferrocenyl
128.35 (СН=, J = 13.2); 130.01 (=С<,
J = 81.8); 131.81 (СН=, J = 3.0); 132.31
(СН=, J = 11.4)
128.22 (СН=, J = 13.7); 130.41 (=С<,
J = 79.2); 131.54 (СН=, J = 3.2); 132.56
(СН=, J = 11.4)
127.98 (СН=, J = 12.5); 131.03 (СН=,
J = 3.0); 131.83 (СН=, J = 10.9); 133.32
(=С<, J = 78.5)
128.08 (СН=, J = 12.5); 131.19 (СН=,
J = 3.0); 131.68 (СН=, J = 10.9); 132.74
(=С<, J = 78.6)
35.55 (Me); 126.44, 129.72 (СН=,
J = 16.1); 137.57 (=С<, J = 124.6)
126.64, 127.02, 128.02, 128.67, 129.94
(СН=, J = 15.9); 137.05, 139.07 (=С<,
J = 121.6)
69.95, 71.75 (СН=, J = 10.0); 73.11
(СН=, J = 12.6); 73.64 (=С<, J = 89.0)
Ferrocenylene
74.26 (СН=, J = 12.0); 75.06 (=С<,
J = 86.9); 75.21 (СН=, J = 9.7)
Selenide 17a. White crystalline substance, m.p. 142—143 °C.
Found (%): С, 68.29; H, 4.31; N, 3.15. C26H20NPSe. Calcuꢀ
lated (%): С, 68.43; H, 4.42; N, 3.07. 1Н NMR (CDCl3), δ: 6.66
(d, 1 H, CH= of indole ring, J = 4.8 Hz); 7.04 (d, 1 H, CH=, Ar,
J = 8.3 Hz); 7.14—7.34 (m, 7 Н, CH=, Ar); 7.44—7.58 (m, 6 Н,
CH=, Ar); 7.64 (d, 1 H, CH=, Ar, J = 7.9 Hz); 7.86—7.96 (m,
4 Н, CH=, Ar).
Selenide 18a. White crystalline substance, m.p. 116 °C.
Found (%): С, 55.69; H, 4.27; N, 8.25. C16H15N2PSe. Calcuꢀ
lated (%): С, 55.66; H, 4.38; N, 8.11. 1Н NMR (CDCl3), δ: 3.83
(с, 3 H, Ме); 7.14 (br.s, 1 Н, —СН= of imidazole ring); 7.22
(br.s, 1 Н, —СН= of imidazole ring); 7.50—7.60 (m, 6 Н,
—СН=, Ph); 7.82—7.90 (m, 4 Н, —СН=, Ph).
lated (%): С, 61.92; H, 4.21; N, 6.88. 1Н NMR (CDCl3) δ,:
7.15—7.27, 7.30—7.35, 7.42—7.54, 7.86—7.94 (all m, 17 H,
—СН= of imidazole ring, Ph).
Selenide 20a. Orange crystalline substance, decomposes at
temperatures above 120 °C. Found (%): С, 58.63; H, 4.32.
C
22H19FePSe. Calculated (%): С, 58.83; H, 4.26. 1Н NMR
(CDCl3), δ: 4.18 (s, 5 Н, ferrocenyl rings); 4.47 (dd, 2 Н,
ferrocenyl rings, J = 2.1 Hz, J = 4.0 Hz); 4.54 (dd, 2 Н, ferrocenyl
rings, J = 1.7 Hz, J = 3.5 Hz); 7.40—7.50 (m, 6 Н, СН=, Ph);
7.70—7.77 (m, 4 Н, СН=, Ph).
Selenide 21a. Orange crystalline substance, decomposes at
temperatures above 140 °C. Found (%): С, 57.19; H, 4.02.
C
34H28FeP2Se2. Calculated (%): С, 57.33; H, 3.96. 1Н NMR
Selenide 19a. Light pink crystalline substance, m.p. 195 °C.
Found (%): С, 62.03; H, 4.34; N, 6.80. C21H17N2PSe. Calcuꢀ
(CDCl3), δ: 4.34 (dd, 4 Н, ferrocenyl rings, J = 1.0 Hz, J =
4.0 Hz); 4.73 (dd, 4 Н, ferrocenyl rings, J = 1.0 Hz, J =

84
Russ.Chem.Bull., Int.Ed., Vol. 52, No. 1, January, 2003
Chevykalova et al.
4.0 Hz); 7.37—7.50 (m, 12 Н, СН=, Ph); 7.60—7.68 (m, 8 Н,
СН=, Ph).
The 13С NMR spectra of the synthesized selenides are preꢀ
sented in Table 3.
12. Ya. L. Gol´dfarb, Yu. B. Vol´kenshtein, and B. V. Lopatin,
Zh. Obshch. Khim., 1964, 34, 969 [J. Gen. Ghem. USSR,
1964, 34 (Engl. Transl.)].
13. A. S. AlvarezꢀInsua, S. Conde, and C. Corral, J. Heterocycl.
Chem., 1982, 19, 713.
14. L. A. Yanovskaya and S. S. Yufit, Organicheskii sintez v
dvukhfaznykh sistemakh [Organic Synthesis in Twoꢀphase Sysꢀ
tems], Khimiya, Moscow, 1982, p. 86 (in Russian).
15. A. F. Pozharskii, B. K. Martsokha, and A. M. Simonov,
Zh. Obshch. Khim., 1963, 33, 1005 [J. Gen. Chem. USSR,
1963, 33 (Engl. Transl.)].
16. W. E. McEwen, J. E. Fountaine, D. N. Schulz, and W.ꢀI.
Shiau, J. Org. Chem., 1976, 41, 1684.
17. H. Schindlbauer, Chem. Ber., 1967, 100, 3432.
18. S. O. Grim, W. McFarlane, and E. F. Davidoff, J. Org.
Chem., 1967, 32, 781.
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Received January 21, 2002;
in revised form July 12, 2002