Synthesis of bis(imidazole-2-thion-4-yl)phosphanes

Article abstract of DOI:10.1002/hc.21043

Novel bis(imidazole-2-thion-4-yl)- phosphanes (2a-d) were synthesized via lithiation of the precursor imidazole-2-thiones followed by the phosphanylation reaction. Oxidation of bis(imidazole-2-thion-4-yl)phosphane 2b-d with elemental sulfur and selenium l

Full text of DOI:10.1002/hc.21043

Heteroatom Chemistry
Volume 00, Number , 2012
Synthesis of
Bis(imidazole-2-thion-4-yl)phosphanes
Susanne Sauerbrey,1 Paresh Kumar Majhi,1 Sebastian Schwieger,1
Anthony J. Arduengo III,2 and Rainer Streubel1
1Institut fu¨ r Anorganische Chemie, Rheinische Friedrich-Wilhelms-Universita¨t Bonn, D-53121
Bonn, Germany
2Department of Chemistry, University of Alabama, Tuscaloosa, AL 35487
Received 3 March 2012; revised 20 June 2012
of biologically active compounds such as antibac-
ABSTRACT: Novel bis(imidazole-2-thion-4-yl)-
terial [1], anti-inflammatory [2,3], analgesic [3],
phosphanes (2a–d) were synthesized via lithia-
antitumor [4,5], anticancer activities [6] etc., and
tion of the precursor imidazole-2-thiones followed
in organic synthesis is well documented [7–10].
by the phosphanylation reaction. Oxidation of
The synthetic access to various C-phosphorylated
bis(imidazole-2-thion-4-yl)phosphane 2b–d with
five-membered N-heterocycles via electrophilic
elemental sulfur and selenium led selectively and in
phosphorylation with P(III) halides is known
good yields to the P-thio (3b–d) and P-seleno (4c)
[10–13]. The coordination of phosphanes to met-
derivatives of bis(imidazole-2-thion-4-yl)phosphanes,
als and the spectroscopic properties of phospho-
respectively. The treatment of 2a,c with phosphorus
rus are two important aspects of this chemistry
trichloride gives the corresponding P-chloro deriva-
[14]. Furthermore, it has been demonstrated that 1-
tives 5a,c. These compounds were unambiguously
methyl-imidazoles substituted at the C2 carbon cen-
characterized by elemental analyses, spectroscopic
ter can be functionalized at position five (C5) with a
and spectrometric methods, in addition by single-
phosphorus-containing group IV [15,16]. Recently,
crystal X-ray structure analysis in the case of 2d.
we showed that imidazole-2-thiones can also be
ꢀ
C
2012 Wiley Periodicals, Inc. Heteroatom Chem 00:1–7,
functionalized at the C4 position with phosphorus-
2012; View this article online at wileyonlinelibrary.com.
containing groups V in a similar fashion [17].
DOI 10.1002/hc.21043
Kuhn demonstrated an efficient synthetic route to
N-heterocyclic carbene (NHCs) III by the reduc-
tion of imidazole-2-thione II with potassium in
INTRODUCTION
boiling tetrahydrofuran [18]. Recently, Gates and
colleagues [19] and Bertrand and coworkers [20]
reported the first examples of C4-phosphanyl sub-
stituted NHCs VI. Two (1-methyl-2-R-imidazoles)
were also added on the phosphorus center, re-
sulting in structures VII and VIII [16]. The com-
pounds of type VIII could be used to synthesize
tripodal ligands [21], which shows interesting co-
ordination properties and can act as a model lig-
and for enzymatic activities. Herein, we present the
synthesis of a series of bis(imidazole-2-thion-4-yl)
phosphanes.
The importance of imidazole I and imidazole-2-
thione II derivatives (see Fig. 1) both in the field
Correspondence to: Anthony J. Arduengo III; e-mail: aj@
ajarduengo.net. Rainer Streubel; e-mail: r.streubel@uni-bonn.de.
Contract grant sponsor: University of Bonn.
Contract grant sponsor: COST action cm0802 “PhoSciNet.”
Contract grant sponsor: National Science Foundation.
Contract grant numbers: CHE-0413521 and CHE-0115760.
Supporting Information is available in the online issue at
wileyonlinelibrary.com.
c
ꢀ
2012 Wiley Periodicals, Inc.
1

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Sauerbrey et al.
1
TABLE 1 31P{ H} NMR Chemical Shifts and Coupling
Constants for Compounds 2a–d
2a
2b
2c
2d
31 P NMR (CDCl3)
δ (ppm)
14.4
10.2
16.1
10.0
16.8
9.3
−57.2
3JPH (Hz)
8.4
in a triclinic lattice with space group P¯ı. Selected
structural parameters are given in Table 2. Crystal-
lographic data are presented in Table 3. The struc-
ture and numbering scheme for 2d is shown in Fig.
2 (the disordered toluene solvate unit is omitted for
clarity).
Compounds 2a–d can be converted into P(V)
derivatives 3b–d, 4c by using classical oxidation
methods (Scheme 2). The reactions of compounds
2b–d with elemental sulfur and selenium appeared
quantitative according to 31P NMR spectroscopic
monitoring. The P-thio (3b–d) and P-seleno (4c)
phosphorylated bis(imidazole-2-thiones) crystal-
lized from the reaction mixtures and thus could
easily be obtained in a pure form. The analytical
data of phosphane sulfides and selenides are given
in the Experimental section. For all P(V) derivatives
described herein, the 31P NMR signal of 3b–d
and 4c was shifted to lower field compared to the
parent phosphanes 2b–d. The same tendencies
were observed before in the series of imidazole-
FIGURE 1 Imidazoles (I), imidazole-2-thiones (II), imidazol-
2-ylidenes (III), and selected phosphorus derivatives IV–VIII.
RESULTS AND DISCUSSION
The imidazole-2-thione derivatives 1a–c, used in
this study, were synthesized according to the re-
ported procedures [22]. The imidazole-2-thiones
were deprotonated in tetrahydrofuran with nBuLi
at –78◦C and allowed to react with 0.5 equiv of
dichloro(organo)phosphane to afford bis(imidazole-
2-thione) phosphanes 2a–d (Scheme 1) selectively.
The 31P NMR chemical shifts and 3 JPH coupling con-
stants to the NMe2 and ortho-phenyl protons for
substituted
phosphane
chalcogens
[16,23].
TABLE 2 Selected Bond Lengths and Angles for 2d
1
2a–d are provided in Table 1. H NMR spectra re-
vealed small couplings to the C5H and none to the
N3-Me protons.
Property
Value
˚
Bond lengths (A)
Single-crystal X-ray diffraction structure anal-
ysis was performed for compound 2d. The crystal
was obtained from a saturated toluene solution at
low temperature (–20◦C). Compound 2d crystallizes
C(1)–P(1)
C(8)–P(1)
C(15)–P(1)
C(2)–S(1)
C(9)–S(2)
C(1)–N(1)
C(8)–N(3)
C(1)–C(3)
C(8)–C(10)
1.817(2)
1.814(2)
1.834(2)
1.680(2)
1.688(2)
1.396(2)
1.398(2)
1.352(3)
1.351(3)
Bond angles (deg)
C(8)-P(1)-C(1)
C(8)-P(1)-C(15)
C(1)-P(1)-C(15)
C(3)-C(1)-P(1)
C(10)-C(8)-P(1)
N(1)-C(2)-N(2)
N(3)-C(9)-N(4)
C(1)-C(3)-N(2)
C(8)-C(10)-N(4)
101.05(8)
98.58(9)
102.45(9)
133.3(2)
128.5(1)
105.0(2)
106.1(2)
108.4(2)
108.4(2)
SCHEME 1 Synthesis of compounds 2a–d.
Heteroatom Chemistry DOI 10.1002/hc

Synthesis of Bis(imidazole-2-thion-4-yl)phosphanes
3
TABLE 3 Crystallographic data for 2d·1/2C7H8
Crystal system
Space group
Triclinic
P -1
˚
A (A)
10.5360(7)
11.0711(7)
˚
b (A)
˚
c (A)
11.7759(7)
65.072(5)
81.417(5)
87.247(5)
α (◦)
β (◦)
γ (◦)
3
˚
V (A )
1231.5(1)
Z
1
dc (g cm−3
)
1.253
0.299
μ(mm−1
)
F(000)
494
Crystal size (mm)
Reflections collected
Reflections unique
Mo Kα radiation (λ, A)
Final R indices (R1)
0.35 × 0.15 × 0.09
12465
5930
˚
0.71073
0.0409
0.0867
0.0722
0.0932
0.856
FIGURE 2 Molecular structure of 2d (at a 30% probability
level).
wR2
R indices (all data) R1
wR2
GOF
in a mixture of mono-, bis-, and tris(imidazole)-
substituted phosphane derivatives. Therefore,
another synthetic methodology was followed by
reacting 2a,c with a stoichiometric amount of
phosphorus trichloride to yield 5a,c as yellow solids
(Scheme 2). The analytical data of 5a,c are given in
Parameters
314
Attempted preparation of the bis(imidazole-2-
thion-4-yl)phosphinous chloride analogous to 5a,c
by phosphorylation of imidazole-2-thiones 1a,c
with phosphorus trichloride in a 2:1 ratio resulted
the Experimental section. Compounds 5a,c have 31
P
NMR chemical shifts similar to their 2a,c analogs,
i.e., 22.6 (5a) and 19.9 (5c).
SCHEME 2 Synthesis of P(V) and P-chloro derivatives (for abbreviation of a–d (see Scheme 1).
Heteroatom Chemistry DOI 10.1002/hc

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Sauerbrey et al.
CONCLUSIONS
synthetic methodology was developed to
anisotropic approximation for non-hydrogen atoms
using SHELXS97 and SHELXL97 [24] program
packages. Hydrogen atoms were calculated on ide-
alized positions and refined isotropically by using a
riding model.
A
synthesize a series of bis(imidazole-2-thion-4-yl)-
phosphanes. The oxidation of bis(imidazole-2-thion-
4-yl)phosphanes occurred selectively to yield the
corresponding PV -E products (E = S, Se) 3b–d
and 4c was firmly established by spectroscopic
and spectrometric methods. The treatment of 2a,c
with phosphorus trichloride leads to correspond-
ing P-chloro derivatives 5a,c. This synthetic route is
amenable to the preparation of multigram quantities
of product in a linear fashion. The new phosphanyl-
and phosphoryl-substituted bis(imidazole-2-thione)
could be of interest in the synthesis of backbone
functionalized imidazol-2-ylidenes.
Typical Lithiation and Phosphanylation
Protocol for the Synthesis of 2a-d
In a Schlenk flask, the imidazole-2-thiones 1a–c
(10 mmol) were dissolved in tetrahydrofuran
(100 mL) and cooled to –78◦C, n-butyl lithium (1.6 M
in n-hexane, 17 mL, 11 mmol) was then added,
and the reaction mixture was slowly warmed to –
40◦C; it was stirred for 2 h at this temperature.
The reaction mixture was cooled again to –78◦C,
the dichlorophosphane (Me2NPCl2 or PhPCl2) (5
mmol) was then added, and the reaction mixture
was stirred for about 18 h while warming to ambi-
ent temperature. It was then concentrated in vacuo
(8 × 10−3 mbar), and the residue was taken up in
dichloromethane and filtered over celite to remove
lithium chloride. The filtrate was collected, and the
solvent was removed in vacuo (8 × 10−3 mbar). The
crude product was then purified via crystallization
from hot toluene (2a–d). Colorless to light yellow
crystals were obtained.
EXPERIMENTAL
General Considerations
The synthesis of the imidazole-2-thiones and the
lithiation reactions were performed under argon,
using common Schlenk techniques and dry sol-
vents. Tetrahydrofuran was dried over sodium
wire/benzophenone, dichloromethane over calcium
hydride, and further purified by subsequent distil-
lation. All used phosphanes were distilled prior to
use and stored under argon. All other chemicals
were used as received. 1,3-Dimethylimidazole-2-
thione (1a) [22a], 1-isopropyl-3-methyl-imidazole-
2-thione (1b) [22b], and 1,3-diphenylimidazole-
2-thione (1c) [22c] were synthesized following
literature protocols. All NMR spectra were recorded
on a Bruker (Germany) AX-300 spectrometer (300.1
MHz for 1H, 75.5 MHz for 13C, 121.5 MHz for
Bis(1,3-dimethyl-imidazole-2-thion-4-yl)-dime-
thylaminophosphane (2a). Yield: 2.42 g (62%),
1
white solid, mp 179◦C. H NMR (300 MHz, CDCl3):
δ 6.60 (d, JP,H = 0.8 Hz, 2H, C5-H), 3.55 (s br, 6H,
N3-CH3), 3.52 (s br, 6H, N1-CH3), 2.65 (d, JP,H
=
1
10.2 Hz, 6H, P-N-CH3). 13C{ H} NMR (75.0 MHz,
CDCl3): δ 165.5 (s, C S), 125.3 (d, JP,C = 8.0 Hz,
C4), 122.8 (d, JP,C = 0.8 Hz, C5), 40.8 (d, JP,C
=
=
31P). The H and 13C spectra were referenced to the
16.0 Hz, P-N-CH3), 35.2 (s, N1-CH3), 33.5 (d, JP,C
1
1
residual proton resonance and the 13C signals of
the deuterated solvents, 31P to 85% H3PO4 as ex-
ternal standard, respectively. Melting points were
determined in one-side melted off capillaries using
a Bu¨chi type S or a Carl Roth type MPM-2 ap-
paratus (Germany), and they are uncorrected. El-
emental analyses were carried out on a Vario EL
gas chromatograph (Germany). Mass spectromet-
ric data were collected on a Kratos MS 50 spec-
trometer (Germany) using EI, 70 eV. The infrared
spectra were recorded on a Nicolet 380 FT-IR spec-
trometer (Germany) using KBr pellets. The single-
crystal X-ray analysis was performed on a STOE
IPDS2T diffractometer (Germany) (Mo Kα radia-
tion, graphite monochromator) at 123(2) K. The
structure was solved by direct methods and re-
fined by full-matrix least-squares technique in an
9.6 Hz, N3-CH3). 31P{ H} NMR (121.5 MHz, CDCl3):
δ 14.4. MS (EI, 70 eV): m/z (%) 329 (100) [M]•+,
285 (72) [M – N(CH3)2]+, 212 (4) [M – N(CH3)2-2S-
CH3]+. HR-ESI-MS: found: 352.0790, calcd 352.0790
as C12H20N5PS2Na+. IR (KBr, cm−1): ν = 3154, 3065,
1574, 1492, 1389, 1181, 664. EA: calcd C 43.75, H
6.12, N 21.26, S 19.47; found: C 43.98, H 6.16, N
20.93, S 19.68.
Bis(1-isopropyl-3-methyl-imidazole-2-thion-4-yl)-
dimethylaminophosphane (2b). Yield: 5.65 g (92%),
white solid, mp 135◦C. 1H NMR (300 MHz,
CDCl3): δ 6.05 (s, 2H, C5-H), 5.05 (hept, JH,H
=
6.8 Hz, 2H, C3H7-CH), 3.54 (s, 6H, N3-CH3), 2.63
(d, JH,H = 10.0 Hz, 6H, P-N-CH3), 1.31 (d, JH,H
=
1
6.8 Hz, 12H, C3H7-CH ). 13C{ H} NMR (75.0 MHz,
3
CDCl3): δ 165.5 (d, JP,C = 1.1 Hz, C S), 126.1 (d, JP,C
=
Heteroatom Chemistry DOI 10.1002/hc

Synthesis of Bis(imidazole-2-thion-4-yl)phosphanes
5
8.4 Hz, C4), 125.6 (d, JP,C = 1.9 Hz, C5), 49.6 (s,
C3H7 − CH), 41.3 (d, JP,C = 16.3 Hz, P-N-CH3), 33.6
(d, JP,C = 10.2 Hz, N3 − CH3), 22.2 (d, JP,C = 8.5 Hz,
Typical Procedure for the Generation of
Phosphane Sulfides (3b–d) and Phosphane
Selenide (4c)
1
N1-C3H7 − CH3). 31P{ H} NMR (121.5 MHz, CDCl3):
A solution of phosphanes 2b–d (3 mmol) in toluene
(10 mL) containing elemental sulfur or selenium
(3 mmol) was heated for 3 h at 110◦C. The reac-
tion mixture was cooled down to ambient temper-
ature. The product precipitated in the form of col-
orless crystals. The obtained crystals were washed
with n-pentane and dried in vacuo (8 × 10−3 mbar).
δ16.1. MS (EI, 70 eV): m/z (%) 385 (100) [M]•+,
341 (88) [M – N(CH3)2]+, 299 (37) [M – 2(C3H7)]+,
257 (16) [C8H14N3PS]+, 230 (10) [C9H17N3PS]+, 91
(100) [C5H5N2]+, 65 (14) [C3HN2]+. HR-MS: found:
385.1522, calcd 385.1535. IR (KBr, cm−1): ν = 3107,
3055, 2970, 1555, 1434, 1406, 1189, 673. EA: calcd
C 49.85, H 7.32, N 18.17, S 16.63; found: C 49.93, H
7.47, N 18.33, S 16.70.
Bis(1-isopropyl-3-methyl-imidazole-2-thion-4-yl)-
dimethyl-aminophosphane Sulfide (3b). Yield: 4.4 g
(95%), white solid, mp 205◦C. H NMR (300 MHz,
1
Bis(1,3-diphenyl-imidazole-2-thion-4-yl)
dimethylamino-phosphane (2c)
CDCl3): δ 6.94 (d, JP,H = 3.4 Hz, 2H, C5-H), 5.05 (hept,
JH,H = 6.8 Hz, 2H, C3H7-CH), 3.71 (s, 6H, N3-CH3),
Yield: 3.85 g (78%), white solid, mp 217◦C. 1H NMR
(300 MHz, CDCl3): δ 7.54–7.16 (m, 20H, C6H5), 6.84
(s 2H, C5-H), 2.38 (d, JP,H = 9.3 Hz, 6H, P-N-CH3).
2.74 (d, JP,H = 13.9 Hz, 6H, P-N-CH3), 1.32 (dd, JH,H
=
1
6.8 Hz, JP,H = 3,7 Hz, 12H, C3H7-CH ). 13C{ H} NMR
3
(75.0 MHz, CDCl3): δ 166.2 (d, JP,C = 5.8 Hz, C S),
122.0 (d, JP,C = 20.7 Hz, C5), 120.8 (d, JP,C = 139.2
Hz, C4), 48.7 (s, C3H7 − CH), 36.2 (d, JP,C = 4.5 Hz,
P-N-CH3), 32.9 (d, JP,C = 9.5 Hz, N3 − CH3), 20.9 (s,
1
13C{ H} NMR (75.0 MHz, CDCl3): δ 166.9 (s, C S),
137.6 (s, N-ipso-Ph), 136.6 (s, N-ipso-Ph), 129.0 (s,
N-Ph), 128.4 (s, N-Ph), 127.0 (d, JP,C = 12.5 Hz, C4),
125.8 (s, N-Ph), 123.4 (s, C5), 40.8 (d, JP,C = 19.1
1
N1-C3H7 − CH3). 31P{ H} NMR (121.5 MHz, CDCl3):
1
Hz, P-N-CH3). 31P{ H} NMR (121.5 MHz, CDCl3):
δ 33.9. MS (EI, 70 eV): m/z (%) 417 (100) [M]•+, 341
(10) [M – N(CH3)2]+, 299 (37) [M•+– 2(C3H7]+, 257
(16) [C8H14N3PS]+, 248 (18) [C8H14N3PS2]+. HR-MS:
found: 417.1247, calcd 417.1239. IR (KBr, cm−1):
ν = 3119, 3064, 1546, 1438, 1409, 1187, 647. EA:
calcd C 46.02, H 6.76, N 16.77, S 23.04; found: C
45.94, H 6.67, N 16.68, S 23.00.
δ16.8. MS (EI, 70 eV): m/z (%) 577 (100) [M]•+,
533 (88) [M – N(CH3)2]+, 326 (5) [C17H16N3PS]+, 251
(20) [C15H11N2S]+, 77(15) [C2H7NP]+. HR-ESI-MS:
found: 577.1519, calcd 577.1524. IR (KBr, cm−1):
ν = 3148, 3065, 1594, 1497, 1384, 1151, 691. EA:
calcd C 66.53, H 4.89, N 12.12, S 11.10; found: C
66.24, H 4.73, N 12.02, S 11.01.
Bis(1,3-diphenyl-imidazole-2-thion-yl)-dimethy-
lamino-phosphane Sulfide (3c). Yield: 1.65 g (90%),
Bis(1-isopropyl-3-methyl-imidazole-2-thion-4-yl)-
phenylphosphane (2d)
1
white solid, mp 195◦C. H NMR (300 MHz, CDCl3):
δ 7.49–7.09 (m, 20H, C6H5), 6.94 (d, JP,H = 3.5
Hz, 2H, C5-H), 2.45 (d, JP,H = 15.1 Hz, 6H,
Yield: 5.90 g (88%), white solid, mp 108◦C. 1H NMR
(300 MHz, CDCl3): δ 7.42–7.32 (m, 5H, C6H5), 6.26
(s, 2H, C5-H), 5.03 (hept, JH,H = 6.8 Hz, 2H, C3H7-
1
P-N-CH3). 13C{ H} NMR (75.0 MHz, CDCl3): δ 169.8
(s, C S), 136.9 (s, N-ipso-Ph), 136.2 (s, N-ipso-Ph),
129.5 (s, N-Ph), 129.0 (s, N-Ph), 127.9 (s, C5), 125.6
CH), 3.48 (s, 6H, N3-CH3), 1.26 (dd, JH,H = 6.8 Hz,
(s, N-Ph), 120.8 (d, JP,C = 141.3 Hz, C4), 37.3 (d, JP,C
=
1
JP,H = 5.3 Hz, 12H, C3H7-CH ). 13C{ H} NMR (75.0
3
1
2.4 Hz, P-N-CH3). 31P{ H} NMR (121.5 MHz, CDCl3):
δ 35.9. HR-ESI-MS: found: 632.1149, calcd 632.1137
as C32H28N5PS3Na+. IR (KBr, cm−1): ν = 3132, 3057,
1595, 1403, 1169, 663. EA: calcd. C 63.03, H 4.63,
N 11.49, S 15.78; found: C 62.81, H 4.49, N 11.21, S
15.62.
MHz, CDCl3): δ 165.3 (s, C S), 133.0 (d, JP,C = 21.2
Hz, C6H5), 130.8 (s, C6H5), 129.5 (d, JP,C = 7.9 Hz,
C6H5), 129.2 (d, JP,C = 34.9 Hz, ipso-C6H5), 128.9
(d, JP,C = 6.7 Hz, C4), 120.1 (d, JP,C = 5.2 Hz, C5),
49.4 (s, C3H7 − CH), 33.4 (d, JP,C = 9.5 Hz, N3-
CH3), 21.7 (d, JP,C = 5.0 Hz, N1-C3H7 − CH3) ). 31P
1
NMR{ H} (121.5 MHz, CDCl3): δ –55.0. MS (EI, 70
eV): m/z (%) 418 (8) [M]•+, 320 (70) [C15H16N4PS3]+,
263 (17) [C13H16N2PS]+, 221 (30) [C10H9N2PS]+, 91
(100) [C5H5N2]+. HR-MS: found: 418.1419, calcd
418.1414. IR (KBr, cm−1): ν = 3140, 3052, 1548,
1434, 1371, 1182. EA: calcd C 57.39, H 6.50, N
13.39, S 15.32; found: C 57.21, H 6.43, N 13.25,
S 15.22.
Bis(1-isopropyl-3-methyl-imidazole-2-thion-4-yl)-
phenyl-phosphane Sulfide (3d). Yield: 6.5 g (81%),
1
white solid, mp 198◦C. H NMR (300 MHz, CDCl3):
δ 7.76–7.09 (m, 5H, C6H5), 6.53 (d, JP,H = 3.9 Hz,
2H, C5-H), 5.04 (hept, JH,H = 6.4 Hz, 2H, C3H7-
CH), 3.62 (s, 6H, N3-CH3), 1.27 (m br, 12H, C3H7-
1
CH ). 13C{ H} NMR (75.0 MHz, CDCl3): δ 167.2
3
Heteroatom Chemistry DOI 10.1002/hc

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Sauerbrey et al.
(d, JP,C = 5.3 Hz, C S), 133.3 (d, JP,C = 3.3 Hz,
C6H5), 131.6 (d, JP,C = 12.6 Hz, C6H5), 129.1 (d,
JP,C = 13.9 Hz, Ph), 127.8 (d, JP,C = 97.4 Hz, ipso-
37.44, H 4.40, N 17.46, S 19.99; found: C 37.69, H
4.56, N 17.21, S 19.76.
C6H5), 122.4 (d, JP,C = 19.3 Hz, C5), 119.4 (d, JP,C
=
Bis ( 1 , 3 - diphenyl - imidazole - 2 - thion - 4 - yl ) -
chlorophosphane (5c). Yield: 1.70 g (92%), orange
solid, mp 249◦C. 1H NMR (300 MHz, CDCl3): δ 7.54–
117.0 Hz, C4), 49.5 (s, C3H7 − CH), 34.1 (s, N3-CH3),
1
21.4 (s, N1-C3H7 − CH). 31P{ H} NMR (121.5 MHz,
CDCl3): δ 10.5. MS (EI, 70 eV): m/z 450 (100) [M]•+,
418 (10) [M – S]+, 352 (15) [C15H16N4PS3]+, 250
(5) [C10H9N2PS2]+, 221 (30) [C10H9N2PS]+. HR-MS:
found: 450.1139, calcd 450.1127. IR (KBr, cm−1):
ν = 3121, 3068, 1548, 1436, 1378, 1186. EA: calcd
C 53.31, H 6.04, N 12.43, S 21.35; found: C 53.20, H
6.13, N 12.38, S 21.37.
1
7.24 (m, 20H, C6H5), 6.90 (s br, 2H, C5-H). 13C{ H}
NMR (75.0 MHz, CDCl3): δ 168.3 (d, JP,C = 1.2 Hz,
C S), 137.0 (s, N-ipso-Ph), 135.8 (d, JP,C = 1.2 Hz,
N-ipso-Ph), 129.4 (s, N-Ph), 129.1 (s, N-Ph), 129.0
(s, N-Ph), 128.7 (s, N-Ph), 127.0 (d, JP,C = 23.3 Hz,
1
C4), 125.6 (s, N-Ph), 122.3 (s, C5). 31P{ H} NMR
(121.5 MHz, CDCl3): δ 19.9. MS (EI, 70 eV, 35Cl):
m/z (%) 568 (100) [M]•+, 533 (62) [M – Cl]+, 317 (8)
[C15H11ClN2PS]+, 281 (25) [C15H11N2PS]+, 251 (30)
[C15H11N2S]+, 77 (40) [C6H5]+. HR-ESI-MS: found:
568.0716, calcd 568.0712. IR (KBr, cm−1): ν = 3116,
3062, 1385, 1168, 773, 762, 693, 471. UV/vis (Et2O):
λmax: 209 nm. EA: calcd C 63.32, H 3.90, N 9.85, S
11.27; found: C 63.19, H 3.80, N 9.77, S 11.19.
Bis ( 1 , 3 - diphenyl - imidazole - 2 - thion - 4 - yl ) -
dimethylamino-phosphane Selenide (4c). Yield: 1.81
g (92%), white solid, mp 190◦C. 1H NMR (300 MHz,
CDCl3): δ 7.48–7.05 (m, 20H, C6H5), 6.87 (d br, JP,H
=
3.8 Hz, 2H, C5-H), 2.37 (d, JP,H = 16.5 Hz, 6H, P-N-
1
CH3). 13C{ H} NMR (75.0 MHz, CDCl3): δ 169.5 (d,
JP,C = 4.2 Hz, C S), 136.8 (s, N-ipso-Ph), 136.0 (s,
N-ipso-Ph), 129.6 (s, N-Ph), 129.0 (s, N-Ph), 128.8
(d, JP,C = 10.7 Hz, C5), 125.6 (s, N-Ph), 119.0 (d,
JP,C = 126.4 Hz, C4), 38.1 (d, JP,C = 3.0 Hz, P-N-
SUPPLEMENTARY MATERIAL
Crystallographic data for the structure reported in
this paper has been deposited with the Cambridge
Crystallographic Data Centre as supplementary pub-
lication no. CCDC 858986 and can be obtained free
of charge on application to CCDC, 12, Union Road,
Cambridge CB2 1EZ, UK; fax: +44 1223 336033; or
deposit@ccdc.cam.ac.uk.
1
CH3). 31P{ H} NMR (121.5 MHz, CDCl3): δ 29.3 (JSe,P
= 807.4 Hz). MS (EI, 70 eV): m/z (%) 657 (65) [M]•+,
577 (55) [M – Se]+, 533 (100) [M – Se-N(CH3)2]+,
281 (100) [C15H11N2PS]+, 251 (68) [C15H11N2S]+. EA:
calcd C 58.53, H 4.30, N 10.67, Se 12.02; found: C
58.39, H 4.22, N 10.53, Se 11.88.
Typical Procedure for the Generation of
Chlorophosphanes 5a,c
ACKNOWLEDGMENT
AJA gratefully acknowledges the Saxon Endowment
of the University of Alabama.
In separate Schlenk flasks, the phosphanes 3a,c
(1 equiv) were dissolved in dichloromethane (10 mL)
and cooled to –20◦C, 1 equiv of phosphorus trichlo-
ride was added to each and the reaction mixtures
were warmed up to ambient temperature. The sol-
vent was removed from each reaction in vacuo (8 ×
10−3 mbar), and the crude products obtained were
each washed several times with n-pentane and then
dried in vacuo (8 × 10−3 mbar).
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