Chemistry of C6F5SeLi and C6F 5SeCl: Precursors to new pentafluorophenylselenium(II) compounds

Article abstract of DOI:10.1515/znb-2004-0511

Pentafluorobenzeneselenenyl chloride, C₆F₅SeCl, was reacted with various nitrogen and chalcogen substituted trimethylsilyl nucleophiles. The products, C₆F₅SeSCN, C₆F ₅SeNSO, (C₆F₅Se)₂NMe, C ₆F₅SeN(Me)SiMe₃, (C₆F ₅Se)₂S and (C₆F₅Se)₂Se, were characterized by spectroscopic methods. The reaction of C₆F ₅SeLi with Me₃XHal compounds gave the products C ₆F₅SeXMe₃ (X = Si, Ge, Sn, Pb). The molecular structure of (C₆F₅Se)₂S has been determined by X-ray diffraction.

Full text of DOI:10.1515/znb-2004-0511

Chemistry of C6F5SeLi and C6F5SeCl: Precursors to
New Pentafluorophenylselenium(II) Compounds
Thomas M. Klapo¨tke, Burkhard Krumm, and Peter Mayer
Department Chemie, Ludwig-Maximilians-Universita¨t Mu¨nchen,
Butenandtstr. 5-13 (D), D-81377 Mu¨nchen, Germany
Reprint requests to Prof. Dr. T. M. Klapo¨tke. Fax: +49 (0)89 2180 77492.
E-mail: tmk@cup.uni-muenchen.de
Z. Naturforsch. 59b, 547 – 553 (2004); received February 2, 2004
Dedicated to Professor Manfred Adelhelm on the occasion of his 65th birthday
Pentafluorobenzeneselenenyl chloride, C6F5SeCl, was reacted with various nitrogen and chalcogen
substituted trimethylsilyl nucleophiles. The products, C6F5SeSCN, C6F5SeNSO, (C6F5Se)2NMe,
C6F5SeN(Me)SiMe3, (C6F5Se)2S and (C6F5Se)2Se, were characterized by spectroscopic methods.
The reaction of C6F5SeLi with Me3XHal compounds gave the products C6F5SeXMe3 (X = Si, Ge,
Sn, Pb). The molecular structure of (C6F5Se)2S has been determined by X-ray diffraction.
Key words: Pentafluorobenzeneselenenyl Pseudohalides, Pentafluorophenylselenolate,
Multinuclear NMR Spectroscopy
Introduction
In the reaction of 2 with Me3SiNCS the ques-
tion arises, whether a selenenyl isothiocyanate C6F5Se
NCS, or a selenenyl thiocyanate C6F5SeSCN is
formed. Based on spectroscopic arguments (77Se NMR
shift and vibrational data), we conclude that the se-
lenenyl thiocyanate C6F5SeSCN (3) is formed. The
77Se NMR resonance of the nitrogen-bound selenenyl
isothiocyanate isomer would appear at lower field, in
the region found for the other SeN species discussed in
this report. Furthermore, the resonance at δ = 482 ppm
agrees nicely with that of the sulfur bonded deriva-
tive (C6F5Se)2S (5), found at δ = 510 ppm. The non-
fluorinated analogue, C6H5SeSCN, is believed to exist
in the thiocyanate form as well, based on infrared data
[6, 7]. The selenenyl thiocyanate 3 undergoes complete
thermal decomposition into the diselane (C6F5Se)2 and
insoluble orange-red polymeric thiocyanogen, when
heated in a vacuum or in solution. The precipitation
of (SCN)x has also been reported for C6H5SeSCN [6]
and CF3SeSCN [8]. The triselane 6 is stable in the
solid state, but in solution undergoes rapid elimina-
tion of red selenium to form the diselane (C6F5Se)2
at ambient temperature. The corresponding sulfane 5
eliminates sulfur in solution after prolonged periods.
A reaction between 2 and (Me3Si)2Te occurred even at
lower temperatures, but immediate tellurium elimina-
The chemistry of pentafluorophenyl selenium spe-
cies was initiated in the late 60’s with the synthesis
of the selane (C6F5)2Se and the diselane (C6F5Se)2
[1 – 3]. Recently, we have discovered facile large scale
syntheses for C6F5Se compounds which employ the
starting material C6F5SeLi (1) and the product of
chlorination, C6F5SeCl (2) [4, 5]. First reactions of 2
with trimethylsilyl nucleophiles furnished C6F5SeBr,
C6F5SeCN and C6F5SeNR2 (R = Me, Et). In this con-
tribution we report on extended studies of reactions of
2 with various selected nucleophiles, as well as the
preparation of trimethyl-Group14-element derivatives
of the type C6F5SeXMe3 (X = Si, Ge, Sn, Pb).
Results and Discussion
Pentafluorobenzeneselenenylchloride C6F5SeCl (2)
is prepared by chlorination of diselane (C6F5Se)2,
which itself is formed by acidic hydrolysis and sub-
sequent aerial oxidation of C6F5SeLi (1) [4]. Upon
treatment of 2 with selected nucleophiles in dichloro-
methane as solvent, various new C6F5Se derivatives,
such as C6F5SeSCN (3), C6F5SeNSO (4), (C6F5Se)2S
(5), (C6F5Se)2Se (6), C6F5SeN(Me)SiMe3 (7), and
(C6F5Se)2NMe (8) are formed (Scheme 1).
c
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T. M. Klapo¨tke et al. · Chemistry of C6F5SeLi and C6F5SeCl
Scheme 1.
tion and formation of the diselane prevented the detec-
tion of (C6F5Se)2Te.
With trimethyl-group14-element chlorides or bro-
mides, the selenolate C6F5SeLi (1) can be converted
in a facile fashion into the corresponding selanes,
C6F5SeSiMe3 (9), C6F5SeGeMe3 (10), C6F5SeSnMe3
(11), and C6F5SePbMe3 (12) (Scheme 2).
The reactions of 2 with Me3SiN3 and AgOCN
(Me3SiNCO does not react) result in very unstable
derivatives, C6F5SeN3 and C6F5SeNCO, which de-
compose already at low temperatures into the dise-
lane. A more detailed description of the reaction of
Me3SiN3 with 2 and with RSeCl compounds in gen-
eral, is given elsewhere [9]. Of comparable unstable
nature as C6F5SeNCO is the trifluoromethyl deriva-
tive CF3SeNCO, which is reported to oligomerize [8].
An exact description of the decomposition pathway
of C6F5SeNCO cannot be given at this time, but at
least another C6F5SeN species can be identified in the
77Se NMR spectrum at δ = 806 ppm with increasing
amounts of (C6F5Se)2.
Scheme 2.
The compounds 9 – 12 are highly moisture sensitive
liquids, which can be distilled and purified in a vacuum
without decomposition, except for 12, which decom-
◦
poses above 50 C in a vacuum into C6F5SeMe and
Me4Pb. Both products were identified by NMR spec-
troscopy. The derivatives 9-11, in particular the silyl
selane 9, should be valuable transfer reagents of the
nucleophilic pentafluorophenyl selenolate moiety.
The NMR data of 9 – 12 are displayed in Table 1.
The increase in weight from silicon to lead causes
an irregular trend for the 77Se NMR shifts and also
for the methyl 13C NMR resonances. A similar trend
occurs for the series of the nonfluorinated analogues
C6H5SeXMe3 (X = Si, Ge, Sn, Pb) [11]. All sele-
nium resonances of 9 – 12 are split into triplets due to
coupling with ortho-fluorine atoms, and are accompa-
nied by 29Si, 117Sn/119Sn and 207Pb satellites. The 77Se
NMR spectrum of the plumbyl derivative 12 is shown
in Fig. 1.
With Me3SiI a slow reaction was observed, the
product being the same as found in the reaction of
(C6F5Se)2 with iodine. Attempted separation of the
product, “C6F5SeI”, resulted in the back reaction
(elimination of iodine and formation of the diselane).
The exact structure remains unknown. The existence
of a labile charge-transfer adduct, (C6F5Se)2·I2, simi-
lar as found in the case of (C6H5Se)2·I2 [10], is pro-
posed.
Following the reactions of 2 with trimethylsi-
lyl amines Me3SiNR2 [4], it was of interest to
check the reactivity towards bis(trimethylsilyl) amines
(Me3Si)2NR and tris(trimethylsilyl) amine (Me3Si)3N.
A reaction of 2 with (Me3Si)2NMe occurs, and de-
pending on reaction time and stoichiometry, the mono-
C6F5SeN(Me)SiMe3 (7), and the di-substituted prod-
uct, (C6F5Se)2NMe (8), are isolable. No noticable re-
action of 2 was observed with (Me3Si)3N.
Crystal structure of (C6F5Se)2S (5)
The molecular structure of bis(pentafluorobenzene-
selenenyl) sulfane (5) is shown in Fig. 2. Other known
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T. M. Klapo¨tke et al. · Chemistry of C6F5SeLi and C6F5SeCl
549
C6F5SeSiMe3
9
C6F5SeGeMe3
10
0.61
–
3.0
–
99.9
132.2
147.7
4.6
C6F5SeSnMe3
11
0.51
C6F5SePbMe3
12
1.35
61.6
9.6
Table 1. NMR data of 9 – 12 (δ
in ppm, J in Hz, CDCl3, 25 ◦C).
δ1H
0.41a
4.5
2JH−Si/Sn/Pb
56.1/53.8
−3.7
a
6JH−F = 0.9 Hz (triplet);
δ
13C CH3
1.7
53.0
98.9
126.8
147.7
4.6
b
c
2JC−Sn = 22.7 Hz; 3JC−Se
=
1JC−Si/Sn/Pb
343/328
100.5b
136.1
235
3.1 Hz; d 3JF−F = 20.6 Hz; e 73Ge,
extremely broad (ca. 1500 Hz),
uncertain.
C-1
102.6
142.6
147.6
3.8
1JC−Se
C-2
147.5
6.9
137.4
139.8
2JC−Se
C-3
137.5c
140.7
−125.2
−154.4d
−161.4
−59
137.4
140.4
−125.1
−154.9d
−161.5
−52
137.2
139.5
−125.0
−157.1d
−162.3
−92
C-4
δ
19F o-
p-
−125.1
−156.2d
−161.8
−135
m-
δ
77Se
1JSe−Si/Sn/Pb
99
18.4
21.4
–
18.9
(78)e
901/860
21.3
978
22.4
247
3JSe−F
29Si/119Sn/207Pb
δ
92
Fig. 2. Molecular structure of (C6F5Se)2S (5) with thermal
ellipsoids at the 50% probability level (only S, Se and C1 la-
beled for clarity). Selected bond lengths and angles (A, ◦):
˚
Se–S 2.177(1), Se–C1 1.915(3), Se–S–Se(i) 108.53(7), S–
Se–C1 99.7(1), C(1)–Se–S–Se(i) 101.9(1), with i = 1 − x,
y, 11/2 −z.
derivative (111.82(1)◦), probably due to the stronger
electron-withdrawing effect of the pentafluorophenyl
˚
groups. The Se–C bond length (1.915(3) A) is in
the same range as found in other C6F5Se(II) com-
˚
pounds (1.90– 1.92 A) [4, 14], but shorter than those
˚
of C6F5Se(IV) compounds (1.95– 1.96 A) [4, 15].
Experimental Section
Fig. 1. 77Se NMR spectrum of 12.
All reactions were carried out under dry nitrogen atmo-
sphere with dried solvents. The trimethylsilyl reagents, sil-
ver cyanate, and the Me3 × Hal derivates were used as
received (Aldrich), except for Me3SiNSO, which was pre-
pared according to the literature [16]. Infrared spectra were
compounds of this type of which the crystal struc-
ture has been determined are [(Me3Si)3CSe]2S [12]
and (2-NO2C6H4Se)2S [13]. The molecule adopts a
transoid conformation with respect to the C2 sym-
metry at the sulfur atom. The Se–S bond length recorded as KBr pellets or neat between KBr or CsBr win-
˚
dows on a Nicolet 520 FT-IR spectrometer, Raman spectra
on a Perkin-Elmer Spectrum 2000 NIR FT-Raman spectrom-
eter (100 mW). The NMR spectra were obtained on a J◦eol
400 Eclipse instrument using CDCl3 as solvent at 25 C.
The chemical shifts are given with respect to (CH3)4Si (1H,
400.18 MHz; 13C, 100.63 MHz; 29Si, 79.43 MHz), LiCl (7Li,
is with 2.177(1) A slightly shorter than those
˚
in [(Me3Si)3CSe]2S (2.213(1)/2.210(1) A) and (2-
˚
NO2C6H4Se)2S (2.202(2) A) and the Se–S–Se(i) an-
gle (108.53(7)◦) is slightly smaller than those found
for the “trisyl” (112.1(1)◦) and the ortho-nitrophenyl
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T. M. Klapo¨tke et al. · Chemistry of C6F5SeLi and C6F5SeCl
Table 2. Crystal data and structure refinement.
(C6F5Se)2S
3), 135.8 (C-4), 111.9 (C-1). – 77Se NMR: δ = −119 (t,
JSe−F = 27.7 Hz). 7Li NMR: δ = 0.8.
Empirical formula
Formula weight
Temperature [K]
Crystal size [mm]
Crystal system
Space group
C12F10SSe2
524.10
200(3)
C6F5SeCl (2). This compound was prepared on a 50 mmol
scale by chlorination of (C6F5Se)2 with sulfuryl chloride as
described in Ref. [4].
0.17×0.12×0.07
monoclinic
C2/c
29.250(2)
4.8316(3)
10.3548(7)
101.743(9)
1432.8(2)
4
General procedure for the reaction of C6F5SeCl with
Me3Si-nucleophiles. Into solutions of 5 mmol of 2 in
10 ml of dichloromethane was added 6 mmol of Me3
SiNCS/Me3SiNSO, or 3 mmol of (Me3Si)2S/(Me3Si)2Se/
(Me3Si)2NMe and the mixture stirred for 2 h at 25 ◦C. Af-
ter removal of the volatile materials the liquid residues were
distilled in a vacuum where appropriate (4 and 7), the solid
residues were purified by vacuum sublimation (5 and 6), re-
spectively. The compounds 3 and 8 decompose completely
upon attempted distillation. Due to the slow reaction with
(Me3Si)2NMe to give (C6F5Se)2NMe (8), it was possible to
isolate the monosubstituted product C6F5SeN(Me)SiMe3 (7)
by using an equimolar ratio of 2 and (Me3Si)2NMe.
˚
a [A]
˚
b [A]
˚
c [A]
β [◦]
3
˚
V [A ]
Z
ρ (calcd.) [g/cm3]
2.430
5.417
984
µMo [mm−1
F(000)
]
θ range [◦]
2.85 – 25.85
−33 ≤ h ≤ 35, −5 ≤ k ≤ 5,
−12 ≤ l ≤ 12
3158
1290 (Rint = 0.0459)
1040
1290/0/114
1.035
0.0352, 0.0959
0.0435, 0.0994
0.642/−0.542
Index ranges
Reflections collected
Independent reflections
Observed reflections
Data/restraints/parameters
Goodness-of-fit on F2
R1, wR2(I > 2σ(I))
R1, wR2 (all data)
C6F5SeSCN (3). Orange liquid (74%). – IR (neat): ν =
2150/2082 m (νSCN), 1634 m, 1591 w, 1514 s, 1492 s,
1422 w, 1397 m, 1376 m, 1346 w, 1286 m, 1257 w,
1148 w, 1105 m, 1089 s, 1034 w, 1011 m, 979 s, 847 w,
821 m, 721 w, 669 w, 625 w, 443 w, 404 w, 381 w,
311 w cm−1. – Raman: ν = 2150 (76, νSCN), 1634 (22),
1397 (19), 1288 (5), 822 (14), 672 (6), 626 (3), 586 (26),
497 (36), 443 (35), 385 (20), 350 (100, νSeS), 243 (14),
224 (5), 163 (21), 133 (28) cm−1. – 19F NMR: δ = −123.5
3
˚
Larg. diff. peak/hole [e/A ]
155.37 MHz), CH3NO2 (14/15N, 28.92/40.56 MHz), CFCl3
(
(
19F, 376.55 MHz), (CH3)4Ge (73Ge, 13.96 MHz), (CH3)2Se
77Se, 76.36 MHz), (CH3)4Sn (119Sn, 149.08 MHz) and
3
4
(m, 2F, 2-F), −145.5 (tt, 1F, 4-F, JF−F = 20.6, JF−F
=
5.0 Hz), −158.2 (m, 2F, 3-F). – 13C{19F} NMR: δ =
(CH3)4Pb (207Pb, 83.39 MHz). Mass spectroscopic data
were obtained from a JEOL Mstation JMS 700 Spektrom-
eter using the direct EI mode with fragments referring to the
nuclei with the highest abundance (for example 80Se). Ele-
mental analyses were performed in-house.
2
147.3 (C-2, JC−Se = 9.3 Hz), 144.2 (C-4), 137.5 (C-3,
3JC−Se = 5.0 Hz), 109.6 (SCN, br), 102.2 (C-1, JC−Se
=
1
149.9 Hz). – 14N NMR: δ = −98 (br, ∆ν1/2 = 1000 Hz). –
77Se NMR: δ = 482 (br). – MS m/z (%): 261 (12)
A Stoe IPDS area detector was employed for data col- [C6F5SeN+], 247 (100) [C6F5Se+], 228 (4) [C6F4Se+],
lection with Mo-Kα radiation. The structure was solved by 197 (17) [C5F3Se+], 155 (25) [C5F5+], 117 (14) [C5F3+]. –
direct methods SIR97 [17] and refined by means of the full- C7F5NSSe (304.1): calcd. C 27.6, N 4.6; found C 27.6, N 4.7.
matrix least squares procedures using SHELXL97 [18] (Ta-
ble 2). All non-hydrogen atoms were refined anisotropically.
Further details are available under the depository number
CCDC–229732 from the Cambridge Crystallographic Data
Centre.
C6F5SeNSO (4). Yellow-orange liquid (89%), b.p.
31 ◦C/0.01 mbar. – IR (neat): ν = 1648 w, 1635 m, 1514 s,
1492 s, 1422 w, 1401 m, 1376 w, 1289 m, 1197 s, 1149 w,
1108 m, 1089 s, 1028 w, 1015 m, 978 s, 825 s, 722 w,
634 m, 613 w, 575 w, 498 w, 457 w, 383 w, 343 m,
Preparation of C6F5SeLi solution in ether. Into a solution 311 w cm−1. – Raman: ν = 1648 (7), 1636 (22), 1402 (18),
of 30 mmol of pentafluorobenzene in 150 ml of diethylether 1290 (3), 1197 (8), 1150 (2), 1068 (6), 1013 (100, νNSO),
was added 30 mmol of n-BuLi (2.5 M in hexanes) at −70 ◦C 826 (11), 635 (9), 615 (5), 587 (39), 498 (38), 456 (32),
during a period of 1 h and the resulting clear solution of 444 (20), 386 (20), 359 (8), 247 (14), 222 (6), 183 (6),
C6F5Li stirred for an additional hour at that temperature. A 136 (31) cm−1. – 19F NMR: δ = −125.7 (m, 2F, 2-
3
4
slight excess of selenium (33 mmol) was added in one por- F), −147.2 (tt, 1F, 4-F, JF−F = 20.5, JF−F = 4.3 Hz),
tion and the mixture allowed to warm up to 0 ◦C in 2 h. The −159.2 (m, 2F, 3-F). – 13C{19F} NMR: δ = 146.0 (C-
2
3
clear greenish solution of C6F5SeLi containing some excess 2, JC−Se = 9.2 Hz), 143.7 (C-4), 137.7 (C-3, JC−Se
=
selenium can be reacted with electrophiles as described be- 5.0 Hz), 103.9 (C-1, JC−Se = 131.5 Hz). – 15N NMR:
1
low. C6F5SeLi (1) in Et2O. – 19F NMR: δ = −130.5 (m, δ = −51.9 (JN−Se = 77.6 Hz). – 77Se NMR: δ = 830 (t,
3
2F, 2-F), −167.7 (m, 2F, 3-F), −168.1 (t, 1F, 4-F, JF−F
=
JSe−F = 11.8 Hz). – MS m/z (%): 309 (42) [M+], 261 (5)
19.9 Hz). – 13C{19F} NMR: δ = 147.7 (C-2), 137.2 (C- [M+−SO], 247 (100) [C6F5Se+], 228 (5) [C6F4Se+],
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197 (24) [C5F3Se+], 155 (32) [C5F5+], 148 (6) [C6F4+], 19F NMR: δ = −126.6 (m, 2F, 2-F), −152.2 (t, 1F, 4-
126 (28) [SeNS+], 117 (23) [C5F3+], 93 (11) [C3F3+], F, JF−F = 20.8 Hz), −160.8 (m, 2F, 3-F). – 29Si NMR:
3
2
48 (5) [SO+], 46 (11) [SN+]. – C6F5NOSSe (308.1): calcd. δ = 18.9 (s, JSi−Se = 3 Hz). – 77Se NMR: δ = 679
3
C 23.4, N 4.6; found C 23.8, N 4.7.
(t, JSe−F = 20.7 Hz). – MS m/z (%): 349 (54) [M+],
334 (19) [M+−CH3], 277 (3) [C6F5SeNHCH3+], 247 (11)
[C6F5Se+], 229 (4) [C6F4SeH+], 197 (4) [C5F3Se+],
168 (7) [C6F5H+], 104 (45) [H2NCH3Si(CH3)3+], 73 (44)
[Si(CH3)3+], 58 (39) [HNSiCH3+], 43 (100) [SiCH3+]. –
C10H12F5NSeSi (348.3): calcd. C 34.5, H 3.5, N 4.0; found
C 33.8, H 3.1, N 4.1.
(C6F5Se)2NMe (8). Pale yellow liquid (45%). – IR (neat):
ν = 2938 m, 2894 m, 2786 w, 1635 m, 1512 s, 1486 s,
1441 w, 1387 m, 1284 m, 1145 w, 1086 s, 1044 w, 1013 m,
977 s, 813 m, 723 w, 699 w, 626 w, 395 w, 311 w cm−1. –
Raman: ν = 2936 (13), 2790 (6), 1635 (47), 1392 (15),
1285 (6), 1145 (6), 817 (12), 684 (8), 626 (10), 585 (75),
495 (100), 443 (68), 433 (70), 387 (46), 358 (28), 244 (20),
226 (23), 195 (18), 146 (15) cm−1. – 1H NMR: δ =
(C6F5Se)2S (5). Yellow crystals (91%), m.p. 79 – 82 ◦C. –
IR (KBr): ν = 1640 m, 1634 w, 1518 s, 1491 s, 1484 s,
1421 w, 1389 m, 1377 w, 1288 w, 1102 m, 1092 s,
1039 w, 1017 m, 978 s, 969 s, 819 m, 722 w, 626 w,
385 w, 311 w cm−1. – Raman: ν = 1640 (32), 1632 (15),
1521 (2), 1389 (21), 1285 (6), 1141 (2), 1094 (2), 821 (31),
627 (8), 586 (50), 496 (51), 444 (28), 387 (68), 374 (27),
364 (100, νSSe), 247 (30), 228 (14), 165 (20), 153 (12),
122 (21) cm−1. – 19F NMR: δ = −125.3 (m, 2F, 2-F),
−149.0 (tt, 1F, 4-F, 3JF−F = 19.9, 4JF−F = 3.5 Hz), −159.7
2
(m, 2F, 3-F). – 13C{19F} NMR: δ = 147.0 (C-2, JC−Se
=
3
8.4 Hz), 142.9 (C-4), 137.4 (C-3, JC−Se = 5.0 Hz), 104.7
(C-1, JC−Se = 152.2 Hz). – 77Se NMR: δ = 510 (tt,
1
3JSe−F = 20.4, JSe−F = 9.9 Hz). – MS m/z (%): 526 (6)
5
6
3
3.61 (quin, JH−F = 0.9, JH−Se = 8.6 Hz). – 13C{19F}
[M+], 494 (17) [M+−S], 334 (3) [M+−S−2Se], 279 (10)
[C6F5SeS+], 247 (76) [C6F5Se+], 228 (5) [C6F4Se+],
197 (16) [C5F3Se+], 167 (100) [C6F5+], 155 (28) [C5F5+],
148 (6) [C6F4+], 117 (22) [C5F3+], 93 (11) [C3F3+]. –
C12F10SSe2 (524.1): calcd. C 27.5; found C 27.4.
2
NMR: δ = 146.0 (C-2, JC−Se = 9.5 Hz), 142.9 (C-
3
1
4), 137.4 (C-3, JC−Se = 5.5 Hz), 106.1 (C-1, JC−Se
=
163.0 Hz), 60.0 (NCH3). – 15N NMR: δ = −365.3. –
19F NMR: δ = −124.8 (m, 2F, 2-F), −149.1 (tt, 1F, 4-
3
4
F, JF−F = 20.4, JF−F = 3.9 Hz), −159.8 (m, 2F, 3-
F). – 77Se NMR: δ = 973 (m). – MS m/z (%): 523 (100)
[M+], 504 (1) [M+−F], 494 (3) [M+−NCH3], 276 (43)
[C6F5SeNCH3+], 247 (97) [C6F5Se+], 197 (21) [C5F3Se+],
168 (15) [C6F5H+], 155 (19) [C5F5+], 117 (11) [C5F3+],
93 (5) [C3F3+]. – C13H3F10NSe2 (521.1): calcd. C 30.0,
H 0.6, N 2.7; found C 30.0, H 0.7, N 2.8.
(◦C6F5Se)2Se (6). Yellow-brown crystals (82%), m. p. 63 –
66 C (dec.). – IR (KBr): ν = 1640 m, 1635 w, 1517 s,
1489 s, 1421 w, 1389 m, 1375 w, 1286 w, 1105 m, 1090 s,
1015 w, 978 s, 818 m, 723 w, 625 w, 377 w, 311 w cm−1. –
Raman: ν = 1639 (19), 1521 (1), 1389 (13), 1284 (4),
1142 (1), 1105 (1), 820 (22), 626 (5), 586 (30), 496 (30),
444 (17), 388 (21), 359 (9), 272 (100, νSeSe), 246 (22),
227 (20), 180 (4), 160 (14), 112 (10) cm−1. – 19F NMR:
Reaction ofC6F5SeCl with Me3SiN3, AgOCN and Me3SiI.
The experiments were carried out as described above and
were monitored by 19F and 77Se NMR spectroscopy. The re-
actions with Me3SiN3 and AgOCN proceeded immediately
under gas evolution, even at lower temperatures. The reac-
tion with Me3SiI was rather slow (several weeks), similar to
the reaction of (C6F5Se)2 with iodine, nevertheless resulting
in the same NMR data.
3
δ = −125.0 (m, 2F, 2-F), −149.7 (tt, 1F, 4-F, JF−F
=
20.5, JF−F = 3.9 Hz), −159.9 (m, 2F, 3-F). – 13C NMR:
δ = 147.2 (C-2), 143.0 (C-4), 137.4 (C-3), 104.0 (C-1). –
4
77Se NMR: δ = 815 (s, 1Se), 421 (tt, 2Se, JSe−F = 21.2,
3
5JSe−F = 8.7 Hz). – MS m/z (%): 574 (3) [M+], 494 (42)
[M+−Se], 414 (3) [M+−2Se], 334 (7) [M+−3Se], 327 (5)
[C6F5SeSe+], 247 (100) [C6F5Se+], 228 (4) [C6F4Se+],
197 (19) [C5F3Se+], 167 (3) [C6F5+], 155 (23) [C5F5+],
148 (4) [C6F4+], 117 (14) [C5F3+], 93 (5) [C3F3+]. –
C12F10Se3 (571.0): calcd. C 25.2; found C 25.8.
Spectroscopic data for C6F5SeN3. – 19F NMR: δ =
−124.5 (m, 2F, 2-F), −147.1 (t, 1F, 4-F, 3JF−F = 20.5 Hz),
−159.2 (m, 2F, 3-F). – 77Se NMR: δ = 911 (br).
Spectroscopic data for C6F5SeNCO. – 19F NMR: δ =
C6F5SeN(Me)SiMe3 (7). Colorless liquid (74%), b.p. 35 –
40 ◦C/0.01 mbar. – Raman: ν = 2960 (50), 2903 (100),
2805 (13), 1636 (34), 1447 (8), 1411 (11), 1386 (8),
1249 (5), 1142 (4), 1058 (4), 848 (5), 804 (9), 749 (6),
686 (10), 632 (41), 584 (56), 493 (93), 477 (66), 443 (29),
387 (29), 357 (21), 316 (10), 245 (21), 217 (26), 176 (16),
145 (18) cm−1. – 1H NMR: δ = 3.10 (t, 3H, NCH3,
3
−124.5 (m, 2F, 2-F), −146.6 (tt, 1F, 4-F, JF−F = 20.8,
4JF−F = 5.2 Hz), −159.1 (m, 2F, 3-F). – 77Se NMR: δ =
819 (br).
Spectroscopic data for “C6F5SeI”. – 19F NMR: δ =
3
−122.4 (m, 2F, 2-F), −147.8 (tt, 1F, 4-F, JF−F = 20.0,
4JF−F = 5.2 Hz), −159.6 (m, 2F, 3-F). – 13C NMR:
δ = 148.3 (C-2), 143.8 (C-4), 137.3 (C-3), 98.3 (C-1). –
77Se NMR: δ = 259 (t, JSe−F = 22.9 Hz).
3
6JH−F = 1.3, JH−Se = 11.0 Hz), 0.08 (s, 9H, SiCH3,
2JH−Si = 6.7 Hz). – 13C{19F} NMR: δ = 146.2 (C-2,
3
2JC−Se = 10.9 Hz), 141.8 (C-4), 137.2 (C-3, JC−Se
=
Reaction of 1 with trimethyl-group14-element chlorides/
5.8 Hz), 107.8 (C-1, 1JC−Se = 160 Hz), 44.0 (NCH3), −0.3 bromides. An ethereal solution of 1 was treated with equimo-
(SiCH3, 3JC−Si = 56.9 Hz). – 14N NMR: δ = −360 (br). – lar amounts of Me3SiCl, Me3GeBr, Me3SnCl, or Me3PbBr,
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T. M. Klapo¨tke et al. · Chemistry of C6F5SeLi and C6F5SeCl
C6F5SeSnMe3 (11). Colorless liquid (90%), b.p. 35 –
respectively, at 0 – 25 ◦C. Immediate precipitation of the
lithium salts occurred with a color change into slight red- 38 ◦C/0.01 mbar. – IR (neat): ν = 2991 m, 2916 m, 1638 m,
dish, while warming to ambient temperature. The salts and 1607 w, 1510 s, 1483 s, 1394 m, 1369 w, 1338 w, 1279 w,
still present excess selenium were filtered from the solution. 1203 w, 1193 m, 1138 m, 1100 m, 1083 s, 1076 s, 1007 m,
After removal of the solvent the residue was distilled in a 973 s, 908 w, 818 s, 778 s, 718 m, 620 w, 537 s, 510 m, 362 w,
vacuum to give the silyl (9), germyl (10), stannyl (11) and 311 w, 228 m cm−1. – Raman: ν = 2994 (8), 2922 (24),
plumbyl (12) selanes as extremely malodorous liquids, which 1639 (10), 1509 (2), 1394 (8), 1279 (2), 1202 (16), 819 (6),
should be stored at temperatures of ca. −18 ◦C at which they 584 (22), 538 (28), 512 (100, νSeSn), 496 (24), 444 (6),
are crystalline solids. Note: distillation of 12 is not recom- 386 (6), 362 (6), 228 (24), 214 (22), 151 (22) cm−1. –
mended because of nearly complete decomposition.
MS m/z (%): 412 (9) [M+], 397 (32) [M+−CH3], 382 (10)
[M+−2CH3], 367 (19) [C6F5SeSn+], 317 (4) [C5F3SeSn+],
247 (10) [C6F5Se+], 165 (100) [Sn(CH3)3+], 135 (34)
[SnCH3+], 120 (5) [Sn+]. – C9H9F5SeSn (409.9): calcd.
C 26.4, H 2.2; found C 26.4, H 2.3.
C6F5SeSiMe3 (9). Colorless liquid (82%), b.p. 33 – 35 ◦C/
0.01 mbar. – IR (neat): ν = 2963 m, 2899 w, 1637 m, 1514 s,
1486 s, 1466 m, 1412 m, 1373 w, 1342 w, 1281 w, 1254 s,
1141 w, 1099 m, 1084 s, 1026 m, 1009 m, 976 s, 846 s, 816 s,
757 m, 719 w, 699 m, 626 m, 353 m, 311 w cm−1. – Raman:
ν = 2962 (33), 2901 (98), 2789 (3), 1638 (30), 1510 (5),
1413 (12), 1397 (20), 1267 (9), 1251 (6), 1141 (4), 850 (4),
816 (18), 757 (11), 699 (8), 626 (73), 584 (52), 496 (76),
444 (26), 385 (29), 373 (30), 353 (100), 255 (23), 231 (41),
210 (42), 165 (32), 144 (20) cm−1. – MS m/z (%): 320 (69)
[M+], 290 (7) [M+−2CH3], 247 (30) [C6F5Se+], 197 (12)
[C5F3Se+], 168 (66) [C6F5H+], 117 (17) [C5F3+], 73 (100)
[Si(CH3)3+], 43 (22) [SiCH3+]. – C9H9F5SeSi (319.2):
calcd. C 33.9, H 2.9; found C 33.9, H 2.8.
C6F5SePbMe3 (12). Colorless liquid (75%), b.p.
◦
42 C/0.01 mbar (dec.). – IR (neat): ν = 3013 w, 2931 m,
1636 m, 1608 w, 1509 s, 1480 s, 1393 m, 1365 w, 1171 m,
1156 m, 1136 m, 1083 s, 1074 m, 1005 m, 972 s, 817 s,
783 m, 716 w, 619 w, 483 m, 459 m, 312 w, 220 m cm−1. –
Raman: ν = 3029 (13), 2932 (22), 1637 (18), 1510 (12),
1391 (16), 1271 (13), 1171 (24), 1156 (22), 817 (17),
584 (27), 484 (49), 460 (100, νSePb), 386 (17), 365 (16),
241 (17), 194 (27), 139 (20) cm−1. – MS m/z (%):
500 (3) [M+], 485 (7) [M+−CH3], 455 (23) [C6F5SePb+],
262 (40) [C6F5SeCH3+], 253 (100) [Pb(CH3)3+], 247 (44)
[C6F5Se+], 223 (50) [PbCH3+], 208 (52) [Pb+], 197 (9)
[C5F3Se+], 168 (10) [C6F5H+], 155 (11) [C5F5+], 117 (9)
[C5F3+], 93 (5) [C3F3+]. – C9H9F5PbSe (498.3): calcd.
C 21.7, H 1.8; found C 22.6, H 1.8.
◦
C6F5SeGeMe3 (10). Colorless liquid (73%), b.p. 39 C/
0.01 mbar. – IR (neat): ν = 2983 m, 2909 m, 1636 m,
1510 s, 1484 s, 1411 m, 1372 w, 1342 w, 1281 w, 1241 m,
1140 w, 1082 s, 1008 m, 975 s, 833 m, 816 s, 760 w,
719 w, 612 m, 569 m, 314 w, 263 m, 244 w cm−1. –
Raman: ν = 2985 (18), 2912 (50), 1637 (19), 1395 (11),
1251 (10), 815 (9), 613 (26), 584 (48), 569 (100, νSeGe),
495 (39), 444 (13), 386 (12), 361 (13), 263 (46), 245 (24),
190 (33), 144 (17) cm−1. – MS m/z (%): 366 (9) [M+],
351 (6) [M+−CH3], 336 (3) [M+−2CH3], 247 (20)
[C6F5Se+], 197 (5) [C5F3Se+], 168 (9) [C6F5H+], 155 (5)
[C5F5+], 119 (100) [Ge(CH3)3+], 89 (13) [GeCH3+]. –
C9H9F5GeSe (363.7): calcd. C 29.7, H 2.5; found C 29.9,
H 2.6.
Acknowledgements
The University of Munich and the Fonds der Chemis-
chen Industrie are gratefully acknowledged for financial
support. We would like to thank Priv.-Doz. Dr. Konstantin
Karaghiosoff for a generous supply of (Me3Si)2Ch (Ch = S,
Se, Te) and Prof. Dr. Peter Klu¨fers for allocation of diffrac-
tometer time.
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