Organometallics 1983,2, 174-175
174
Sllicon-Carbon Unsaturated Compounds. 15. Synthesis and Molecular Structure of Stable Disllacyclopropanes Mltsuo Ishlkawa, laHiroshl Suglsawa,la Tallchi HIguchi,*lb Koji MatsuI,lb Makoto Kumada,*la Ken Hirotsu,lband Jun Iyoda" Department of Synthetic Chemistry, Faculty of Engineering Kyoto University, Kyoto 606, Japan Department of Chemistry, Faculty of Science Osaka City University, Sugimotocho Sumiyoshi-ku, Osaka, Japan and Government Industrial Research Institute Osaka Ikeda, Osaka 563, Japan Received September 28, 1982
Summary; Two stable disilacyclopropanes lI1,2,2-tetramesityl-3-[bis(trimethylsilyl)methylene]-and 111,2,2-tetramesityl-3-[ phenyl(trimethylsilyI)methylene] 1,2disilacyclopropane (3 and 7) have been prepared by addition of dimesitylsilylene to 1,l -dimesityl-3,3-bis(trimethylsilyl)-1silapropadiene and lIl-dimesityl-3-phenyl-3-(trimethylsilylb 1-silapropadiene, respectively. Preliminary results of an X-ray diffraction study of 3 are described.
Scheme I
RC-CSi(Mes),SiMe, Me,Si
1, R
=
6, R
= Ph
r
R\
SiMe,
c=c/ \ / Si
Mes'
M ' es
1
4 , R = Me,Si 8, R = Ph R,
Me,Si/
,
C=C=Si (Mes)
Me,Si
5, R =
1
2
-
All efforts to prepare disilacyclopropanes had been unsuccessful until in 1976 Seyferth and Duncan provided chemical evidence that a disilacyclopropanederivative was formed in the reaction of l-chloro-2-(bromonorcaranyl)tetramethyldisilane with butyllithium.2 The presence of the disilacyclopropane was inferred on the basis of its reaction with methanol to give the product arising from cleavage of the silicon-silicon bond., It could not be isolated or even detected spectroscopically. In this paper, we report the first synthesis of two stable disilacyclopropanes 1,1,2,2-tetramesityl-3-bis(trimethylsilyl)methyleneand 1,1,2,2-tetramesityl-3-[phenyl(trimethylsilyl)methylene]-1,2-disilacyclopropane and preliminary results of X-ray diffraction study of the latter compound and of ab initio MO calculations for simplified model compounds. When a solution of 0.8105 g (1.86 mmol) of 1,l-dimesityl-2,2,2-trimethyl-l-[ (trimethylsilyl)ethynyl]disilane4(1) and 1.6317 g (3.95 mmol) of 2,2-dimesitylhexamethyltrisilane (2) in 120 mL of dry hexane was photolyzed by irradiation with a low-pressure mercury lamp bearing a Vycor filter for 7 h a t -40 to -20 0C,5yellow crystals identified as 1,1,2,2-tetramesityl-3-[bis(trimethylsilyl)methylene]-1,2-disilacyclopropane(3) [0.3199 g (25% (e) 288 (22450), 364 (8970), yield); mp 158 "C dec; UV A, 415 nm (5640)] were formed, which could be readily isolated by column chromatography, in addition to 20% yield of l,l-dimesityl-2,3-bis(trimethylsilyl)-l-silacyclopropene (4), with 30% of the starting material 1 being unchanged. Since it has been well established recently that the photolysis of 1 affords silacyclopropene 4 and 1,l-dimesityl3,3-bis(trimethylsilyl)-l-~ilapropadiene~~~ ( 5 ) , while 2 yields (1) (a) Kyoto University. (b) Osaka City University. (c) Government Industrial Research Institute Osaka. (2) Seyferth, D.; Duncan, D. P. J. Organomet. Chem. 1976,111, C21. (3) Intermediary formation of disilacyclopropanes has been reported, for example: (a) Roark, D. N.; Peddle, G. J. D. J . Am. Chem. SOC. 1972, 94, 5837. (b) Wulff, W. D.; Goure, W. F.; Barton, T.J. Ibid. 1978,100, 6236. (c) Chen, T.-P.; Cohen, B, H.; Gaspar, P. P. J. Organomet. Chem. 1980, 195, C1. (4) Ishikawa, M.; Nishimura, K.; Sugisawa, H.; Kumada, M. J . Organomet. Chem. 1980, 194, 147. (5) The photolysis of the same mixture a t room temperature gave 3 only in a trace amount. (6) Paper 14 in this series: Ishikawa, M.; Nishimura, K.; Ochiai, H.; Kumada, M. J . Organomet. Chem. 1982,236, 7.
I
II (Mes),Si-Si
(Mes),
3, R = Me,Si 7, R = Ph
Mes
=
dime~itylsilylene,~ the formation of 3 can be explained in terms of the reaction of 5 with dimesitylsilylene (Scheme I). Because photochemical degradation of 1 also involves the extrusion of dimesityl~ilylene,~ 3 was expected to be formed in the photolysis of 1 in the absence of 2. However, we could not isolate 3 from this reaction mixture, although a trace amount of 3 could be detected by TLC. The structure of 3 was confirmed by spectroscopic analysis ['H NMR 6 0.01 (s, 18 H, Me&), 2.15 (s, 12 H, p-CH3),2.25 (s, 24 H, o-CHJ, 6.50 (br s, 8 H, ring protons); NMR 6 (upfield from tetramethylsilane) -6.5 (SiMe,), -48.5 (SiMesJ; mass spectrum, M+ 7021 as well as elemental analysk8 Similar irradiation of a mixture of 0.9620 g (2.18 mmol) of l,l-dimesityl-2,2,2-trimethyl-l(phenylethyny1)disilane (6) and 0.3328 g (0.81 mmol) of 2 in 100 mL of hexane for 3.5 h at room temperature yielded 0.2158 g (14% yield) of yellow crystals of 1,1,2,2-tetramesityl-3-[phenyl(trimethylsily1)methylenel-1,2-disilacycl~propane~ (7) (mp 203 "C dec; UV ,A, ( E ) 284 (18180), 316 (13500), 382 nm (5180)), in addition to 62% yield of l,l-dimesityl-2-phenyl-3-(trimethylsilyl)-l-silacyclopropene(8). Here again, 7 may result from the addition of dimesitylsilylene to the 1-silapropadiene intermediate 9.1° In a previous paper,4 we reported this yellow compound to be 1,1,2,2-tetramesityl-2-phenyl-3-(trimethylsilyl)1,2-disilacyclobutane. However, this has turned out to be an erroneous assignment.l' (7) West, R.; Fink, M. J. Science (Washington,DC) 1981,214, 1343. (8) For 3. Anal. Calcd for C44H62Si4:C, 75.14; H, 8.89. Found: C, 75.09; H, 8.73. (9) For 7: 'H NMR 6 -0.13 (s, 9 H, Me,Si), 2.00 (s, 12 H, o-CH,), 2.11 (s, 6 H, p-CH,), 2.16 (s, 6 H, p-CHJ, 2.36 (s, 12 H, o - C H ~ )6.38 , (s,4 H, mesityl ring protons), 6.56 (s,4 H, mesityl ring protons, 6.6-7.2 (m, 5 H, phenyl ring protons); lSSi 6 (upfield from Me,Si) -5.7 (SiMeJ, -56.0 (%(Me&), -63.3 (Si(Mes),). Anal. Calcd for C47H58Si3:C, 79.82; H, 8.27. Found: C, 80.01; H, 8.32. (10) The yield of 1-silapropadiene 9 was determined t o be ca. 20% from the photolysis of 6 in the presence of methanol.
0276-733318312302-0174$01.50/0 0 1983 American Chemical Society
Organometallics 1983, 2, 175-177
175
Figure 1. Stereoscopic view of 1,1,2,2-tetramesityl-3-[phenyl(trimethylsilyl)methylene]-1,2-disilacyclopropane (7). D2 h
112.7
D2k
113.8
1.480
121.3
Si
C1
4 I
117.7
H H
10
The sum of the bond angles of C(2l)-Si(l)-Si(2), C(12)-Si(l)-Si(2), and C(12)-Si(l)-C(21) is 355.1' which is consistent with the corresponding values obtained from MO calculations for 10 (355.9') and for 11 (356.4'), while the sum of the bond angles of C(39)-Si(2)-Si(l), C(30)Si(2)-Si(l), and C(3O)-Si(2)-C(39) is 343.4'. These results suggest that Si(l), C(12), C(21), Si(2), C(30), and C(39) atoms lie in almost the same plane. Two mesityl groups on Si(1) and Si(2) atoms, A and C rings, are fairly parallel to each other. The inter-ring distances C(21)-C(30) and C(24)-C(33) are 3.38 and 4.25 A, respectively. The bond lengths of Si-Si (2.327 (2) A) and two Si-C bonds (1.907 (4) A (average)) in the disilacyclopropane ring are consistent with those of the respective normal bond. The bond angles of Si-C-Si and C-Si-Si in the ring are 75.2 (2) and 52.4 (1)' (average),respectively. Interestingly, these values are in good agreement with those obtained from MO calculations for 10 but not for 11 as shown in Figure 2. The chemical behavior of the disilacyclopropanes is currently being examined and will be reported elsewhere.
11 N
Figure 2. Geometries of 3-methylene-l,2-disilacyclopropane (10) and disilacyclopropane (1 1). In contrast to the photolysis of 1,when 6 was photolyzed in the absence of 2, compound 7 was obtained in 8% yield,'l together with l-silacyclopropene 8 (65% yield). Both disilacyclopropanes 3 and 7 are stable toward atmospheric oxygen and moisture. They do not react with alcohols at room temperature. The structure of 7 was determined by X-ray diffraction study. We also carried out ab initio MO calculations for 3-(methylene)-1,2-disilacyclopropane(10) and disilacyclopropane (ll).12J3The crystals of 7 are triclinic of space group Pi with cell dimensions a = 16.710 (3) 8,b = 13.150 (2) A, c = 11.268 (3) A, a = 70.96 (2)', /3 = 66.94 (2)', y = 69.87 (2)'; V = 2085.6 (7) A3, and D, = 1.171 Kg MW3 (2 = 2). The structure was solved by direct method.15 Only the 3491 reflections with I > 2 4 were used in the least-squares refinement ( R = 0.053). Figure 1 shows a stereoscopic view of a single molecule. The disilacyclopropane ring and a plane consisting of Si(3), C(2), and C(6) atoms are almost coplanar with the dihedral angle of 7.6'.
Acknowledgment. We are grateful to Dr. K. Kitaura of Osaka City University for useful discussions and the MO calculations. We are also indebted to the Crystallographic Research Center, Institute for Protein Research, Osaka University, and Institute for Molecular Science for the use of computers. Registry No. 1, 75529-54-3;2,79184-72-8;3, 83846-02-0;4, 75529-57-6;6, 75529-55-4;7, 83846-03-1;8, 75535-87-4;10, 83846-04-2;11, 51130-21-3.
Supplementary Material Available: A listing of observed and calculated structure factor amplitudes and tables of positional and anisotropicthermal parameters and bond lengths and angles (17 pages). Ordering information is given on any current masthead page.
Macrocycles Containing Tin. Two Syntheses of 1,1,6,6,11,11,16,16-Octaphenyl-l,6,11, W-tetrastannacycloelcosane and a Synthesis of 1,l ,B,b-Tetraphenyl-1,6-distannacyclodecane
'
(11) All spectral data for the previous compound were identical with those of 7. (12) The ab initio MO calculations for 10 and 11 were carried out by using a 3-21G basis set.14 The geometries were optimized with the energy gradient technique. (13) Morokuma, K.; Kato, S.; Kitaura, K.; Ohmine, I.; Sakai, S.; Obara, S. IMS Computer Center Program Library, The Institute for Molecular Science, 1980; Program No. 0372. (14) (a) Gorden, M. S.;Binkley, J. S.; Pople, J. A.; Pietre, W. J.; Hehre, W. J. J. Am. Chem. SOC. 1982,104, 2797. (b) Binklev, J. S.: PoDle, J. A.: Hehre, W. J. Ibid. 1980, 102, 939. (15) Germain, G.; Woolfson, M. M. Acta Crystallog., Sect. B 1968, B24, 91.
Martin Newcomb, Yutaka Azuma, and Arlene R. Courtney Department of Chemistry, Texas A& M University College Station, Texas 77843 Received September 1, 1982
Summary: The title syntheses are described. The synthetic and purification and analytical methods employed are of general utility for the preparation and functionalization of members of this class of compounds.
0276-733318312302-0175$01.50/0 0 1983 American Chemical Societv
