1,4-Diselenine synthesis by Diels-Alder reaction of a novel exocyclic 1,2-diselone: X-ray crystal structure of (5,6-dimethoxycarbonyl-1,4-diselenine-2,3-dithiolate)Ni(dppe) [dppe = 1,2-(Ph2P)2C2H4]

Article abstract of DOI:10.1039/a706629e

The salt (NBu₄)₂[Zn(dsit)₂] 6 has been converted into the polymer (C₃S₃Se₂)_n 7 which is a source of the reactive 1,2-diselone 8, trapping of which with dimethyl acetylenedicarboxylate affords the 1,4-diselenine derivative 9, which is subsequently transformed into the 1,4-diselenine-2,3-dithiolate species 11, characterised by the X-ray crystal structure of a nickel complex 12.

Full text of DOI:10.1039/a706629e

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1,4-Diselenine synthesis by Diels–Alder reaction of a novel exocyclic
1,2-diselone: X-ray crystal structure of
(5,6-dimethoxycarbonyl-1,4-diselenine-2,3-dithiolate)Ni(dppe)
[dppe = 1,2-(Ph2P)2C2H4]
Antony Chesney, Martin R. Bryce,* Andrei S. Batsanov and Judith A. K. Howard
Department of Chemistry, University of Durham, South Road, Durham, UK DH1 3LE
The salt (NBu4)2[Zn(dsit)2] 6 has been converted into the
polymer (C3S3Se2)n 7 which is a source of the reactive
1,2-diselone 8, trapping of which with dimethyl acetylenedi-
carboxylate affords the 1,4-diselenine derivative 9, which is
subsequently transformed into the 1,4-diselenine-2,3-dithiol-
ate species 11, characterised by the X-ray crystal structure of
a nickel complex 12.
contaminated with a variety of unidentified components.
1,2-Diselones are extremely rare species.2c Electron diffraction
experiments7 clearly revealed that a cyclic 1,2-diselenete
structure (cf. structure 2A) is favoured over the acyclic diselone
structure F3CC(Se)–C(Se)–CCF3. However, this is less likely to
be the situation for intermediate 8, which is the first exocyclic
1,2-diselone: the diselenete tautomer of 8 would be a very
strained bicyclic system.
The synthesis of unusual organoselenium heterocycles, espe-
cially via cycloaddition chemistry of reactive NNSe1 and CNSe2
bonds, has recently attracted considerable attention. For
example, the low-yielding synthesis of 1,4-diselenine derivative
3 from the unstable 1,4,2-diselenazine 1 was presumed to occur
via the transient 1,2-diselone intermediate 2, or the 1,2-di-
selenete tautomer 2A (Scheme 1).2c We now report an entirely
different approach to an exocyclic 1,2-diselone intermediate
and its efficient trapping reaction to yield the highly-function-
alised bicyclic 1,4-diselenine system 9 which is subsequently
transformed into the nickel complex 12.
Conversion of the thione functionality in 9 into the oxo
derivative 10 proceeded almost quantitatively on reaction with
mercuric acetate in a mixture of CHCl3 and AcOH. Opening of
the 1,3-dithiole ring of 10 was achieved by reaction with
MeONa in anhydrous MeOH: the disodium salt of 5,6-di-
methoxycarbonyl-1,4-diselenine-2,3-dithiolate 11 thereby
formed reacted in situ with NiCl2(dppe) [dppe
= 1,2-
(Ph2P)2C2H4] to afford the dark green dithiolene complex
(5,6-dimethoxycarbonyl-1,4-diselenine-2,3-dithiolate)Ni-
(dppe) 12. Complexation of 1,4-dithiine-2,3-dithiolate units
with nickel species has been previously reported both by
Rauchfuss3 and Bereman8 but, to the best of our knowledge, this
is the first time the 1,4-diselenine-2,3-dithiolate system has
been prepared. X-Ray analysis of crystals of complex 12, grown
from MeCN, unambiguously proved the structure of the
complex (Fig. 1).‡
1,4-Dithiine synthesis by reactions of either the dimer 43 or
the polymer 54 of the C3S5 unit4b,5 has been reported. We chose
to investigate the selenium-containing salt (NBu4)2[Zn(dsit)2]
(dsit = 1,3-dithiole-2-thione-4,5-diselenolate) 66 as a novel
precursor for 1,2-diselones. Zinc salt 6 was easily prepared on
a multi-gram scale, according to the literature procedure
employing the more reactive red form of selenium.6a Oxidation
of 6 with I2 in EtOH–acetone at 250 °C afforded a highly
insoluble, air-stable† compound (C3S3Se2)n, assumed to be
polymer 7, in excellent yield. Treatment of 7 with PBu3 in
CH2Cl2 at 20 °C in the presence of excess dimethyl acetyl-
enedicarboxylate (DMAD) afforded the bicyclic 1,4-di-
selenine derivative 9 in 57% yield, presumably via the
intermediacy of the highly-reactive 1,2-diselone 8 (or a PBu3
complex of 8) (Scheme 2). The use of PBu3 to depolymerise 7
was more successful than the usual method employed for the
sulfur analogue (C3S5)n 5, which is heated in a solvent such as
benzene, toluene, dioxane or chlorobenzene.4 The use of these
conditions with 7 led to poor yields of adduct 9, which was
In complex 12, the nickel atom adopts a square planar
coordination, distorted by a slight (6.5°) tetrahedral twist. The
S
2-
Se
Se
Se
Se
S
S
S
S
S
i
S
S
Zn
S
Se
Se
+
2 (NBu4
)
n
7 n = >2
6
ii
Se
Se
Se
CO2Me
S
S
S
S
X
S
Se
CO2Me
iii
Se
Me
Me
Se
Se
Me
Me
Me
Me
NMe2
8
9 X = S
10 X = O
Se
Se
N
Se
iv
2'
1
2
Ph Ph
Na+ –S
Na+ –S
Se
Se
Se
CO2Me
CO2Me
S
CO2Me
CO2Me
P
Ni
S
S
v
Se
Me
Me
CO2Me
CO2Me
S
S
S
P
Se
Ph Ph
11
12
Se
S
n
3
Scheme 2 Reagents and conditions: i, I2 (2.1 equiv.), EtOH–acetone, 250
to 20 °C, 2 h; ii, PBu3 (1 equiv.), DMAD (2 equiv.), CH2Cl2, 20 °C; iii,
Hg(OAc)2, CHCl3–AcOH (3:1 v/v), 20 °C, 12 h; iv, NaOMe, MeOH, 30
min; v, NiCl2 (dppe)
4 n = 2
5 n = >2
Scheme 1
Chem. Commun., 1997
2293

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Footnotes and References
* E-mail: m.r.bryce@durham.ac.uk
† The analysis and reactivity of this material were unchanged by storage in
a sealed container on the bench for at least three months.
‡ Satisfactory elemental analysis were obtained for 7, 9, 10 and 12. Selected
data for 9: mp 215–217 °C; dH (CDCl3) 3.86 (6 H, s); dC (CDCl3) 53.72,
125.30, 136.15, 163.12 and 216.32; m/z (CI) 435 (80Se, 25%), 58 (100);
nmax (KBr)/cm21 1723, 1703, 1574, 1248 and 1049. For 12: mp > 250 °C;
dH ([2H6]DMSO) 3.56 (4 H, t, J 7.8), 3.66 (6 H, s), 7.55 (12 H, m) and 7.69
(8 H, m); nmax (KBr)/cm21 1721, 1566, 1434 and 1242.
S(2)
C(2)
Se(2)
C(4)
Se(1)
C(3)
P(2)
P(1)
§ Crystal data for 12: C34H30NiO4P2S2Se2·C2H3N, M = 886.3, T = 150 K,
monoclinic, space group C2/c (no. 15), a = 41.722(2), b = 9.199(1),
c = 19.599(1) Å, b = 104.17(1)°, V = 7293(1) Å3, Z = 8, Dx = 1.61
C(1)
Ni
S(1)
g cm23, graphite-monochromated Mo-Ka radiation, l
= 0.71073 Å,
m = 27.7 cm21, crystal size 0.50 3 0.35 3 0.24 mm, 44429 reflections
(10294 unique) with q < 61.5° measured using a Siemens SMART CCD
area detector; Rint = 0.078 before, 0.047 after face-indexing (integration)
absorption correction (Tmin,max = 0.310, 0.573), full-matrix least-squares
refinement using SHELXTL software, on F2 of all data to wR = 0.067
(non-H atoms anisotropic, H isotropic; MeCN molecule disordered over
two positions with occupancies of 78.3 and 21.7(5)%; total of 562
variables); for 9030 observed data with I > 2s(I), R(F) = 0.026; residual
Drmin,max = 0.51, 20.47 e Å23. CCDC 182/635.
Fig. 1 Molecular structure of 12. Bond distances (Å): Ni–S(1) 2.168(1), Ni–
S(2) 2.173(1), Ni–P(1) 2.175(1), Ni–P(2) 2.191(1), S(1)–C(1) 1.750(2),
S(2)–C(2) 1.755(2), C(1)–Se(1) 1.917(2), C(2)–Se(2) 1.917(2), C(1)–C(2)
1.343(2), C(3)–Se(1) 1.918(2), C(4)–Se(2) 1.922(2), C(3)–C(4) 1.338(2).
1 M. R. Bryce and A. Chesney, J. Chem. Soc., Chem. Commun., 1995,
195.
2 (a) H. Fischer, K. Treier, C. Troll and R. Stumpf, J. Chem. Soc., Chem.
Commun., 1995, 2461; (b) N. Takeda, N. Tokitoh and R. Okazaki,
Angew. Chem., Int. Ed. Engl., 1996, 35, 660; (c) S. Yoshida,
M. R. Bryce and A. Chesney, Chem. Commun., 1996, 2375.
3 X. Yang, T. B. Rauchfuss and S. Wilson, J. Chem. Soc., Chem.
Commun., 1990, 34.
4 (a) O. Y. Neiland, Y. Y. Katsens and Y. N. Kreitsberga, Z. Org. Chim.,
1989, 25, 592; (b) N. Svenstrup and J. Becher, Synthesis, 1995, 215.
5 G. Steimecke, H.-J. Sieler, R. Kirmse and E. Hoyer, Phosphorus Sulfur,
1979, 7, 49.
Se(1)C(1)C(2)Se(2) moiety forms dihedral angles of 6.5° with
the planar NiS2C2 ring and of 52.8° with the
Se(1)C(3)C(4)Se(2) plane. The ester substituents at C(3) and
C(4) are inclined to the latter plane by 48.5 and 55.3°,
respectively.§ The folding of the diselenine ring in 12 is similar
to that observed in [1,4]diselenino[2,3-b:5,6-bA]di[1]benzo-
selenole (54°) and 1,2,3,4,5,6,8,9,10,11,12,13-dodecahy-
drodicycloocta[1,4]diselenine10 (49°), but larger than in nickel
complexes with isoelectronic 2,3-dithiolato-1,4-dithiine ligands
(28–43°).3,11
In summary, we have devised a short and expedient route to
the 1,2-diselone 8 which has been converted to the 1,4-di-
selenine derivative 9 and hence the nickel complex 12. This
methodology affords a new and efficient approach to the
synthesis of highly-functionalised derivatives of the rare
1,4-diselenine ring system. Further research into the Diels–
Alder trapping of 1,2-diselone intermediate 8, and the down-
stream organic and organometallic reactions of the products
derived therefrom, will be reported in due course.
6
(a) R. M. Olk, A. Ro¨hr, B. Olk and E. Hoyer, Z. Chem., 1988, 28, 304;
(b) H. Poleschner, R. Radeglia and J. Fuchs, J. Organomet. Chem.,
1992, 427, 213; (c) J. Gar´ın, J.Orduna, M. Saviro´n, M. R. Bryce,
A. J. Moore and V. Morisson, Tetrahedron, 1996, 52, 11063.
7 A. B. Borisenko, M. Broschag, I. Hargittai, T. M. Klapo¨tke,
D. Schro¨der, A. Schulz, H. Schwartz, I. C. Tornieporth-Oetting and
P. S. White, J. Chem. Soc., Dalton Trans., 1994, 2705.
8 J. H. Welch, R. D. Bereman, J. Bordner, W. Hatfield and J. H. Helms,
Inorg. Chem., 1985, 24, 2905.
9 V. P. Litvinov, I. A. Dzhumaev, G. V. Gridunova, V. E. Shklover,
Yu. T. Struchkov and B. M. Zolotarev, Bull. Acad. Sci. USSR, Div.
Chem. Sci., 1985, 34, 782.
10 M. R. J. Dorrity, A. Lavery, J. F. Malone, C. P. Morley and
R. R. Vaughan, Heteroatom Chem., 1992, 3, 87; F. R. Fronczek,
H. E. Folsom and P. W. Rabideau, private communication to CCDC,
1995, ref. code PAPKUM01.
We are grateful to the EPSRC for funding this work and to the
Leverhulme Trust for a scholarship (to A. S. B.) and the Royal
Society for a Leverhulme Senior Research Fellowship (to
J. A. K. H.).
11 H. Kim, A. Kobayashi, Y. Sasaki, R. Kato, H. Kobayashi, T. Nakamura,
T. Nogami and Y. Shirota, Bull. Chem. Soc. Jpn., 1988, 61, 2559.
Received in Cambridge, UK, 12th September 1997; 7/06629E
2294
Chem. Commun., 1997