The selective formation of a 1,2-disilabenzene from the reaction of a disilyne with phenylacetylene

Article abstract of DOI:10.1039/c8dt03081b

A stable 3,5-diphenyl-1,2-disilabenzene was selectively synthesized by the reaction between the isolable disilyne TbbSiSiTbb (Tbb = 2,6-[CH(SiMe₃)₂]₂-4-t-Bu-phenyl) with phenylacetylenes. Its molecular structure and physical properties were examined and compared to those of the 1,2-disilabenzene that was obtained from the reaction between TbbSiSiTbb and acetylene. Moreover, a plausible formation mechanism for this reaction is discussed.

Full text of DOI:10.1039/c8dt03081b

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The Selective Formation of a 1,2-Disilabenzene from the Reaction
#
of a Disilyne with Phenylacetylene
Received 00th January 20xx,
Accepted 00th January 20xx
a
a,b
c
d
Tomohiro Sugahara, Jing-Dong Guo, Daisuke Hashizume, Takahiro Sasamori,* Shigeru
e
a,b
Nagase, and Norihiro Tokitoh
DOI: 10.1039/x0xx00000x
www.rsc.org/
A
stable 3,5-diphenyl-1,2-disilabenzene was selectively benzene, considering the unique π-electron character of
5
2 2 2 2
synthesized by the reaction between the isolabe disilyne disilenes (R Si=SiR ) relative to olefins (R C=CR ). The only
TbbSi≡SiTbb (Tbb
phenylacetylenes. Its molecular structure and physical properties an isolable disilyne (RSi
=
2,6-[CH(SiMe
3
)
2
]
2
-4-t-Bu-phenyl) with synthetic route to 1,2-disilabenzenes involves the reaction of
SiR) with acetylenes, i.e., a formal
≡
were examined and compared to those of the 1,2-disilabenzene [2+2+2] cycloaddition (Scheme 1). Sekiguchi reported the first
6
that was obtained from the reaction between TbbSi≡SiTbb and successful isolation of a stable 1,2-disilabenzene from the
Si
acetylene. Moreover, a plausible formation mechanism for this reaction of the stable disilyne R Si
Si
Si
≡SiR
6a
(
I;
R
=
7
reaction is discussed.
Si(iPr)[CH(SiMe
3
)
2
]
2
)
with phenylacetylene. However, the
separation and purification of the two-isomers obtained, i.e.,
,5-diphenyl- and 4,5-diphenyl-1,2-disilabenzene is
Among the simple organic hydrocarbon molecules,
benzene occupies a unique position given its characteristic
aromaticity. This aromaticity arises from the delocalization of
3
problematic due to their instability under atmospheric
conditions.
its six π-electrons, which is the most distinguishing feature
1
-conjugated systems. Benzene
relative to linear or cyclic
π
analogues that incorporate at least one heavier group 14
element have generated much interest not only with respect
to a comparison with the all-carbon system of benzene, but
also with regard to creating novel building blocks for
optelectronic materials, regardless of the difficulties
associated with isolating such species on account of their
2
intrinsically high susceptibility toward self-oligomerization.
Recently, the synthesis and isolation of stable metallabenzenes
that include heavier group 14 elements have been
accomplished by using bulky substituents, which allowed
3
,4
examining their unique physical and chemical properties.
Among these, 1,2-disilabenzenes are one of the most
fascinating targets, especially with respect to the effect of
replacing a C=C with a Si=Si unit in the 6π aromatic system of
Scheme 1. Synthesis of 1,2-disila- and 1,2-digerma-benzenes.
We have already reported the synthesis of stable 1,2-
6
disilabenzenes from the reactions of the stable diaryldisilyne
b
8
3 2 2 3 3
BbtSi≡SiBbt (II; Bbt = 2,6-[CH(SiMe ) ] -4-[C(SiMe ) ]-phenyl)
with acetylenes. The reaction of disilyne II with
phenylacetylene resulted in the predominant formation of the
corresponding 3,5-diphenyl-1,2-disilabenzene together with
unidentified by-products, which prevented us from purifying
3,5-diphenyl-1,2-disilabenzene
and
acquiring
detailed
structural information. Conversely, the reaction of the stable
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diaryldigermyne TbbGe
9
≡
GeTbb (III; Tbb = 2,6-[CH(SiMe
3
)
2
]
2
-4- disilacyclobutadienes (Int-1) via the electrophilic attack of the
Si moiety toward the C -bond followed by an
intramolecular ring expansion (Scheme 3).
tBu-phenyl) with phenylacetylene proceeded selectively to Si
≡
≡C π
1
0
4,6a,9b,13
afford the corresponding 3,5-diphenyl-1,2-digermabenzene.
Thus, the regioselectivity of the formation of 1,2-
dimetallabenzenes should depend on the features of the
substituents on the dimetallyne precursors. Herein, we report
reactions of Tbb-substituted disilyne with acetylenes, which
lead in some cases to the selective formation of 1,2-
disilabenzenes. Calculated mechanisms for the formation of
Si
Tbb- and R - substituted 3,5- and 4,5-diphenyl-1,2-
disilabenzenes are also described.
In accordance with the synthetic procedures for
TbbGe≡GeTbb (III), Tbb-substituted disilyne TbbSi≡SiTbb (1)
was prepared by the reduction of the corresponding
1
1
dibromodisilene
characterized using spectroscopic and X-ray diffraction
techniques. Disilyne exhibits structural features that are
similar to those of the previously reported stable disilynes
2 (Scheme 2). Isolated disilyne 1 was fully
1
I
7
,8,12
and II
,
i.e.,
1
exhibits a short SI
≡
Si bond length [2.1050(15)
Å] and a considerable trans-bent structure [Si–Si–C angle:
31.42(9)˚], suggesting substantial Si
Si triple-bond character. Scheme 3. Plausible mechanism for the formation of 1,2-
In solution, the triply bonded silicon nuclei in
show a disilabenzenes from a disilyne and phenylacetylene.
Si = 16.2, which is comparable
Si = 16.7). These physical properties of suggest
a negligible electronic perturbation of the Si Si moiety by the
1
≡
1
2
9
characteristic Si NMR signal at
δ
8
to that of II
(
δ
1
≡
Tbb groups, which stands in contrast to the case of the Bbt
groups.
Scheme 2. Synthesis of disilyne
1
and its subsequent reactions
and
with acetylenes to afford 1,2-disilabenzenes
3
4.
Exposure of an n-hexane solution of
atm) at r.t. resulted in a color change from dark to light yellow with phenylacetylene. (a) R = R
within 10 minutes, and 1,2-disilabenzene was isolated in
Int-1b) case.
1 to acetylene gas (1 Figure 1. Potential energy surfaces of the reactions of Int-1
1
4
Si
(
Int-1a) case, (b) R = Tbb
3
(
quantitative yield similar to the case of II. In contrast to the
reaction of Tbb-substituted digermyne III with acetylene,
9
The subsequent reaction, i.e., the insertion of the C≡C
which furnished a 9,10-digermabarrelene by-product, no Si- moiety of phenylacetylene into the Si–C bond of Int-1 should
1
4
containing by-product was observed in the crude mixture. be the regioselectivity-determining step (Scheme 3). In both
Si
Subsequently,
at room temperature. The reaction smoothly furnished 3,5- steps: (i) the addition of PhCCH (Int-1
diphenyl-1,2-disilabenzene in quantitative yield.
closure (Int-2 Int-3 ), and (iii) an isomerization (Int-3
The observed regioselectivity should represent
Pro-4 ). According to these processes, the insertion of
manifestation of the remarkable difference between the cases phenylacetylene into the 1,4-Si–C bond of Int-1 would furnish
of silyl-substituted disilyne and Tbb-substituted disilyne
3,5-diphenyl-1,2-disilabenzenes (Pro-4a,b), while that into the
The reaction mechanism for the formal [2+2+2] cycloaddition 2,3-Si–C bond would generate 4,5-diphenyl-1,2-disilabenzenes
of disilynes with two molecules of phenylacetylene has already
Pro-7a,b). However, the selectivity can hardly be rationalized
been investigated theoretically. Initially, a formal [2+2] in terms of the thermodynamic stability of Pro-4 and Pro-7
1
was treated with phenylacetylene in n-hexane cases, i.e. R = R or Tbb, the entire process consists of three
→
Int-2 ), (ii) a ring-
/5
4
/
5
→
/
6
/6
a
→
/7
I
1.
(
,
Si
cycloaddition between the Si
≡
Si moiety of the disilyne and the given that the predominant product for R = R (Pro-4a) is by
C≡
C moiety of phenylacetylene should afford 3-phenyl-1,2- 5.1 kcal/mol less stable than the minor product Pro-7a
.
2
| J. Name., 2012, 00, 1-3
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Therefore, we calculated the potential energy surface (PES) for the slightly bent structure of 1,2-Tbb
2
-1,2-digermabenzene
Si
9
Int-1 to Pro-4 and Pro-7 for R = R and Tbb (Figure 1). For R = (8.6˚). The Si–Si, Si–C, and C–C bond lengths fall between the
Si
16
R , the reactions should proceed with almost the same corresponding single and double bond lengths, suggesting a
barriers toward Pro-4a and Pro-7a. However, the barriers in partial delocalization of the 6 electrons over the [Si ] rings.
the final steps, i.e., (iii) the isomerization from disila-Dewar- Considering these structural parameters in their entirety, it
benzenes Int-3a 6a to 1,2-disilabenzenes Pro-4a 7a, show a seems feasible to conclude that these disilabenzenes exhibit
slight difference, where the process from Int-3a to Pro-4a is by considerable aromaticity on account of the cyclic conjugation
.4 kcal/mol more favorable than that from Int-6a to Pro-7a systems with 6 -electrons.
These results can be used to rationalize the experimental
results in terms of a competitive formation of Pro-4a and Pro- Table 1. Experimentally observed and theoretically calculated
in a 3:2 ratio in the reaction between disilyne and structural parameters.
π
2 4
C
/
/
0
.
π
7a
I
phenylacetylene. Conversely, for R = Tbb, a different reaction
*
calc
*
3
3
4
4
calc
barrier was found in (ii) the ring-closure process from Int-
*
2b
/
5b to Int-3b
/
6b between the PESs for Pro-4b and Pro-7b
,
Si1–Si1 /Si2 [Å]
2.2094(6)
2.2308
1.7998
-----
2.2093(14)
2.2303
1.7909
1.8293
1.3920
1.3940
1.4155
while the barriers in the other steps, i.e., (i) and (iii) are almost
identical for Pro-4b and Pro-7b. Higher barriers were
calculated for the pathway from Int-5b to Int-6b (3.3 kcal/mol)
relative to that from Int-2b to Int-3b (0.3 kcal/mol), and the
difference (3.0 kcal/mol) should be sufficient to afford Pro-4b
exclusively with absolute selectivity.
Si1–C1 [Å]
Si2–C4 [Å]
C1–C2 [Å]
C3–C4 [Å]
1.8094(12)
-----
1.785(4)
1.833(4)
1.384(5)
1.388(5)
1.415(5)
1.3733(17)
-----
1.3753
-----
*
C2–C2 /C3 [Å]
1.413(3)
1.4047
internal angles of
the [Si C ] ring [˚]
2 4
7
19.9
719.8
719.2
718.5
3
*
calculated at the B3PW91/6-31G(2d,p) level of theory.
2
9
The Si NMR spectra of
3
and
4
revealed characteristic
: 61.7
4: 59.7/72.7 ppm). The chemical shifts were reproduced
signals for their [Si C ] rings in the lower-field region (
3
2 4
Si1
Si1*
ppm;
by GIAO calculations
suggests that disilabenzenes
1
7
(
3
: 55.2 ppm;
and
4
: 55.6/74.5 ppm), which
C1*
C2*
C1
C2
3
4 retain in solution the
structures observed in the crystalline state in solution. In
1
addition, the lower-field shifted NMR resonances for the H
4
1
3
and C nuclei in the six-membered [Si C ] rings (δH = 7.7-8.1,
2
4
δC = 131-146) suggest the existence of a ring current in the 1,2-
18,19
disilabenzene rings. NICS-scan calculations
on the
optimized structures support the considerable aromaticity of
1
9
Si1 Si2
disilabenzene
Moreover, we carried out TD-DFT calculations,
revealed the electron-transitions of 3calc (374 nm, f = 0.227;
3 [NICS(0.6) = –8.3, NICS (1.1) = –20.9].
zz
1
9
which
C4
C3
C1
C2
3
68 nm, f = 0.057) and 4calc (416 nm, f = 0.159; 385 nm, f =
.138) that were assigned to the contamination of some
0
π
→π*
transitions of the [Si C ] disilabenzene moieties. These
2
4
calculated absorptions are in good agreement with the
observed λmax values for (397 nm, = 5100; 363 nm, ε =
400) and (442 nm, = 9,300; 385 nm, ε = 11,000). The
broadened absorption of the n-hexane solution of 1,2-Bbt2-
,2-disilabenzene (λmax = 378 nm) should most likely be
interpreted in terms of an overlap of the two characteristic
absorptions similar to the cases of and
3
ε
Figure 2. Molecular structures of
3
(top) and
4 (bottom).
8
4
ε
(
ORTEP drawings at 50% probability level; solvent molecules
1
5
and hydrogen atoms omitted for clarity.)
1
The structural parameters of
3 and 4 were unambiguously
3
4.
determined by single-crystal X-ray diffraction analyses (Figure
1
5
2
and Table 1).
Notably, disilabenzene 3 exhibits a
crystallographic C axis through the central ring similar to 1,2- Conclusions
2
9
Tbb -1,2-digermabenzene. The bond angle sums around the Si
2
In summary, we have synthesized and isolated 1,2-
disilabenzenes and from the reactions of the stable disilyne
TbbSi SiTbb ( ) with acetylenes. It should be noted that the
reaction of with phenylacetylene afforded the 3,5-diphenyl-
,2-disilabenzene selectively, which stands in contrast to the
atoms in the [Si C ] ring [3: 355.5˚; 4: 356.7˚/355.7˚] indicate
2
4
3
4
an almost planar geometry as in the case of 1,2-Bbt -1,2-
2
≡
1
disilabenzenes. In addition, the internal angle sums in the six-
1
membered [Si C ] rings (3: 719.9˚; 4: 719.2˚) suggest planarity
2
4
1
that is similar to that in benzene, which stands in contrast to
reaction of the silyl-substituted disilyne with phenylacetylene.
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Si
While the reaction mechanisms are similar to the Tbb- and R -
substituted cases, the absolute regioselectivity of the former
could be explained based on detailed theoretical calculations.
7
8
A. Sekiguchi, R. Kinjo and M. Ichinohe, Science, 2004, 315
755-1757.
T. Sasamori, K. Hironaka, Y. Sugiyama, N. Takagi, S. Nagase,
,
1
Y. Hosoi, Y. Furukawa and N. Tokitoh, J. Am. Chem. Soc.,
The experimentally observed physical properties of
3 and 4 as
2008, 130, 13856-13857.
(a) T. Sasamori, T. Sugahara, T. Agou, J.-D. Guo, S. Nagase, R.
Streubel and N. Tokitoh, Organometallics, 2015, 34, 2106-
well as the results from the theoretical calculations suggest
considerable levels of aromaticity.
9
2
109. (b) T. Sugahara, J.-D. Guo, Y. Karatsu, Y. Furukawa, A.
E. Ferao, S. Nagase and N. Tokitoh, Bull. Chem. Soc. Jpn.,
016, 89, 1375-1384.
2
Acknowledgements
1
1
1
0 T. Sugahara, J.-D. Guo, T. Sasamori, S. Nagase and N. Tokitoh,
Angew. Chem., Int. Ed., 2018, 57, 3499-3503.
1 T. Agou, N. Hayakawa, T. Sasamori, T. Matsuo, D. Hashizume
and N. Tokitoh, Chem.-Eur. J., 2014, 20, 9246-9249.
2 S. Ishida, R. Sugawara, Y. Misawa and T. Iwamoto, Angew.
Chem., Int. Ed., 2013, 52, 12869-12873.
This work was supported by JSPS KAKENHI grants JP15H03777,
15K13640, and JP20109013 from MEXT (Japan), a Grant-in-Aid
for Research at Nagoya City University, the Joint
Usage/Research Center (JURC, Institute for Chemical Research
(
ICR), Kyoto University), the Integrated Research Consortium 13 (a) C. Cui, M. M. Olmstead and P. P. Power, J. Am. Chem.
Soc., 2004, 126, 5062-5063. (b) N. Y. Tashkandi, L. C.
Pavelka, C. A. Caputo, P. D. Boyle, P. P. Power and K. M.
Baines, Dalton Trans., 2016, 45, 7226-7230. (c) L. Zhao, C.
Jones and G. Frenking, Chem.-Eur. J., 2015, 21, 12405-
on Chemical Science (IRCCS), and Kyoto University Research
Coordination Alliance (KURCA), and the Collaborative Research
Program of Institute for Chemical Research, Kyoto University
(grant No. 2015-99). T. Sugahara gratefully acknowledges
1
support from a grant-in-aid for JSPS fellows (JP16J05501). The 14 B3PW91-D3(BJ)/lanl2dz+d for Si, 6-31G(d) for C,H. Frequency
2413.
calculations and IRC calculations to confirm the PESs were
carried out at the B3PW91-D3(BJ)/3-21G* level of theory.
XRD measurements on
3 were carried out at JASRI and BL02B1
in SPring-8 (2016B1716). We would like to thank Mr. Toshiaki
Noda and Ms. Hideko Natsume at Nagoya University for the
expert manufacturing of custom-tailored glassware.
1
5 Crystallographic data for 1:
C
48
H
98Si10, FW 956.16, crystal size
.15×0.12×0.08 mm , –170 ˚C, = 0.71073 Å, monoclinic,
C2/c (#15), a = 19.8244(4) Å, b = 12.3683(2) Å, c =
3
0
λ
3
2
=
=
7.2326(5) Å–,3β = 104.974(2)˚, V = 6450.5(2) Å , Z = 4, Dcalcd
–1
0.985 g cm ,
7700/277, GOF = 1.239, Completeness = 99.8%, R
(I)] = 0.0529, wR (all data) = 0.1240, largest diff. peak
and hole 0.643 and –0.332 e.Å . CCDC-1830586. 3:
, FW 1086.34, crystal size 0.40×0.35×0.20
= 0.3024(1) Å, orthorhombic, Pnna(#52), a
18.1857(3) Å, b = 30.4174(5) Å, c = 12.6976(2) Å, V =
ꢀ = 0.230 mm , θmax = 27.997˚, refl./param.
Notes and references
1
[
I>2
σ
2
–3
#
Dedicated to Emeritus Professor Kohei Tamao on the
occasion of his 77th birthday.
52 6 6
C H102Si10·C H
3
mm , –183 ˚C,
1
V. J. Minkin, M. N. Glukhovtsev and B. Y. Simkin, in
Aromaticity and Antiaromaticity; Electronic and Structual
Aspects, Wiley-Interscience, 1994.
λ
=
7
θ
3
–3
–1
023.8(2) Å , Z = 4, Dcalcd = 1.027 g cm ,
max = 11.325˚, refl./param. = 7977/351, GOF = 1.062,
[I>2 (I)] = 0.0348, wR (all data) =
.0973, largest diff. peak and hole 0.71 and –0.23 e Å .
CCDC-1830587. 4: 110Si10, FW 1160.41, crystal size
.11×0.06×0.06 mm , –170 ˚C, = 0.71073 Å, triclinic, space
group P–1 (#2), a = 13.2542(4) Å, b = 14.3679(5) Å, c =
ꢀ = 0.035 mm ,
2
(a) G. Maier, G. Mihm and H. P. Reisenauer, Chem. Ber.,
1
982, 115, 801-803. (b) B. Solouki, P. Rosmus, H. Bock and
Completeness = 98.9%, R
1
σ
2
–3
G. Maier, Angew. Chem., Int. Ed. Engl., 1980, 19, 51-52. (c)
G. Maier, G. Mihm and H. P. Reisenauer, Angew. Chem., Int.
Ed. Engl., 1980, 19, 52-53. (d) C. L. Kreil, O. L. Chapman, G.
T. Burns and T. J. Barton, J. Am. Chem. Soc., 1980, 102, 841-
0
64
C H
3
0
λ
8
42. (e) G. Maier, K. Schöttler and H. P. Reisenauer,
2
6
0
=
0.4533(7) Å,
α
=
85.985(3)˚,
β
=
89.418(2)˚,
γ
=
=
3
–3
Tetrahedron Lett., 1985, 26, 4079-4082. (f) G. Märkl and P.
Hofmeister, Angew. Chem., Int. Ed. Engl., 1979, 18, 789-790.
6.661(3)˚, V = 3565.4(2) Å , Z = 2, Dcalcd = 1.081 g cm ,
ꢀ
–
1
.219 mm ,
θ
1.057, Completeness = 99.6%, R
max = 24.999˚, refl./param. = 12508/625, GOF
[I>2 (I)] = 0.0622, wR
2
(
1
g) G. Märkl and W. Schlosser, Angew. Chem., Int. Ed. Engl.,
988, 27, 963-965. (h) G. Märkl and D. Rudnick, Tetrahedron
1
σ
(
all data) = 0.1594, largest diff. peak and hole 0.815 and –
–
3
.435 e Å . CCDC-1830588.
Lett., 1980, 21, 1405-1408. (i) G. Märkl, D. Rudnick, R.
Schulz and A. Schweig, Angew. Chem., Int. Ed. Engl., 1982,
21, 221-222. (j) P. Jutzi, M. Meyer, H. P. Reisenauer and G.
0
1
6 M. Kaftrory, M. Kapon and M. Botoshansky, in The Chemistry
of Organic Silicon Compounds, 1998, , Chapter 5.
2
Maier, Chem. Ber., 1989, 122, 1227-1230.
1
1
1
7 HCTH407/6-311G(3df,p)//B3PW91/6-31G(2d,p)
8 A. Stanger, J. Org. Chem., 2006, 71, 883-893.
9 (GIAO- or TD-)B3PW91/6-311G(3df,p)//B3PW91/6-31G(2d,p)
3
(a) N. Tokitoh, Acc. Chem. Res., 2004, 37, 86-94. (b) N.
Tokitoh, Bull. Chem. Soc. Jpn., 2004, 77, 429-441. (c) Y.
Mizuhata, S. Fujimori, T. Sasamori and N. Tokitoh, Angew.
Chem., Int. Ed., 2017, 56, 4588-4592.
4
5
S. Nagase, Bull. Chem. Soc. Jpn., 2014, 87, 167-195.
(a) R. West, M. J. Fink and J. Michl, Science, 1981, 214, 1343-
1
2
344. (b) T. Sasamori and N. Tokitoh, Bull. Chem. Soc. Jpn.,
013, 86, 1005-1021. (c) R. C. Fishcher and P. P. Power,
Chem. Rev., 2010, 110, 3877-3923. (d) V. Ya Lee and
Sekiguchi, in Organometallic Compounds of Low-Coordinate
Si, Ge, Sn and Pb: From Phantom Species to Stable
Compounds, Wiley & Sons, New York, 2010. (e) M. Kira and
T. Iwamoto, Adv. Organomet. Chem., 2006, 54, 73-148.
(a) R. Kinjo, M. Ichinohe, A. Sekiguchi, N. Takagi, M.
6
Sumimoto and S. Nagase, J. Am. Chem. Soc., 2007, 129,
766-7767. (b) J. S. Han, T. Sasamori, Y. Mizuhata and N.
7
Tokitoh, Dalton Trans., 2010, 9238-9240.
4
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