Organometallics 1992, 11, 1593-1597 (CD2C12):6 2.98 (s,6HI NMeJ, 3.67 (8,24 H, OCH2),7.56-7.93 (m, 6 H, aromatic). 18-Crown-6 Potassium Salt of (8-(Dimethylamino)naphthy1)phenyltnfluorosilicate (4b): colorless crystals (94% ); mp >280 "C. And. CdC for C ~ 4 1 F 3 N 0 6 S i K C, 56.59;HI 6.45; N, 2.20. Found: C,56.87;H, 6.53;N, 2.43. 'H NMR (CD2C12): 6 2.91 (a, 6 H, NMe2), 3.37 (8, 24 HI OCHJ, 6.9-7.98 (m, 11 H, aromatic). 18-Crown-6 Potassium Salt of 1,5-Bis(tetrafluorosilicato)-l,S-bis(dimethy1amino)naphthalene-Tetrakis(methanol) (5b). In this particular case, the reaction was performed in THF, and the compound was recrystallized from methanol giving colorless crystals containing two molecules of methanol per potassium ion (81%): mp 260 O C dec. Anal. Calc for C42HdBN2016Si2K2: C, 43.66;H, 6.98; N, 2.42. Found: C, 43.44;H, 6.38;N, 2.50. MS (FAB neg): m / z 419 (A2--K+), 841 (A2-.-K+--A2-). IH NMR (CD2C12):6 2.84 (s, 12 H, NMe2),3.31 (12HI CH,OH), 3.55 (8, 48 H, OCH2),4.71 (4H, MeOH), 7.24 (d, 2 H, JHH 7 Hz), 7.54 (d, 2 H, JHH 7 Hz). Crystal Structure of the 18-Crown-6 Potassium Salt of (8-(Dimet hy1amino)napht hy1)tetrafluorosilicate (3b). Crystals of the title complex 3b were grown by cooling a saturated acetone solution in a nitrogen atmosphere. Elongated colorless plates were obtained. Preliminary Weissenberg photographs established a monoclinic unit cell with space group P2,ln (No. 14). A small plate was sealed inside a Lindemann glass capillary with the [lo01direction parallel to the 4 axis of the diffractometer. Effluorescence occurred to some extent at the crystal surface. X-ray Data Collection. Data were collected on a CAD-4 automated diffractometer with graphite-monochromatized Mo Ka radiation (A = 0.71069 A). Lattice constants (Table VI) came from a least-squares refinement of 25 reflections obtained in the range 11.4 C 28 C 35.0". The intensities of three standard reflections were monitored after intervals of 60 min; no significant change in these intensities occurred. The structure amplitudes were obtained after the usual Lorentz and polarization reductions. Only the reflections having u(F)/F C 0.33 were considered to be observed. No absorption corrections were made.
1593
Structure Determination and Refinement. Direct methods (1980version of the MULTAN program) were used to solve the structure and to give the positions of the silicon atom and three of the fluorine atoms, which were used to phase a Fourier map. This Fourier map gave the coordinates of the potassium atom, and two subsequent Fourier syntheses revealed all the nonhydrogem atoms of the complex along with the four atoms of the trapped acetone molecule. The atomic scattering factors were taken from ref 27. After three cycles of leastaquares refinement with isotropic thermal parameters to all atoms, the silicon, potassium, fluorine, oxygen, and nitrogen atoms were refined anisotropically. At this stage the conventional R factor was 0.086. The hydrogen atoms were positioned by calculation (SHELX-76 program),and refinement converged to the final R value of 0.062. The final atomic coordinatm are listed in Table VII. Individual bond lengths are listed in Table I and bond angles in Table 11. Table VIII, anisotropic thermal parameters, and Table IX,calculated hydrogen atom coordinates, and a list of observed and calculated structure factors are available as supplementary material.
Acknowledgment. F.C. thanks Prof. J. Lapasset, Groupe de Dynamique des Phases CondensBes, L.A. au CNRS No. 233, UniversitB de Montpellier 11, for t h e use of t h e Weissenberg camera. Registry No. la (coordination compound (CC) entry), 77773-10-5; la (silane entry), 87996-42-7; lb, 139312-46-2; 2a (CC 2a (silane entry), 139312-41-7; 2b, 139346-59-1; entry), 139404-51-6; 3a (CC entry), 108034-64-6;3a (silane entry), 121497-40-3;3b, 139312-48-4;4a (CC entry), 108022-89-5;4a (silane entry), 139312-42-8; 4b, 139312-50-8; 5a (CC entry), 139312-44-0; 5a (silane 5b, 139404-53-8. entry), 139312-43-9; Supplementary Material Available: Tables of anisotropic thermal parameters and hydrogen atom coordinates (2pages); a listing of structure factor amplitudes (9pages). Ordering information is given on any current masthead page.
Photolysis of Organopolysilanes. Photochemical 1,P-Silyl Migration of 2-(2-Phenylethenyl)- and 2-(2,2-Diphenylethenyl)-Substituted Trisilanes Atsutaka Kunai, Toshihiro Kawakami, Yoichi Matsuo, and Mitsuo Ishikawa" Department of Applied Chemistty, Faculty of Engineering, Hiroshima University, Kagamiyama, Higashi-Hiroshima 724, Japan Received July 25, 199 1
The photochemical behavior of 2-(Zphenylethenyl)-2-(trimethylsilyl)hexamethyltrisilane (la), 2-(2,2diphenylethenyl)-2-(trimethylsilyl)hexamethyltrisilane(lb), and 2-(2,2-diphenylethenyl)-Zphenylhexamethyltrisilane (IC) has been studied. Irradiation of @)-la with a low-pressure mercury lamp initially resulted in cis-trans isomerization and then afforded (E)-2-phenyl(trimethylsilyl)ethene((E)-2a) and (Z)-2-phenyl(trimethylsilyl)ethene ((Z)-2a) in addition to @)-la and (Z)-la. Irradiation of l b afforded 2,2-diphenyl(trimethylsilyl)ethene (2b) and 3-phenyl-1,1,2-tris(trimethylsilyl)-l-silaindene(3b),while IC afforded 2b,1,3-diphenyl-l,2-bis(trimethylsilyl)-l-silaindene (312), and 1,3-diphenyl-l-(trimethylsilyl)-lsilaindene (412). A possible mechanism leading to the observed products is described.
Introduction We have demonstrated that permethylpolysilane oligomers and s-electron-system-substitutedpolysilanes are photoactive, and the fate of photochemically excited po-
mercury lamp results in ring contraction with simultaneous extrusion of dimethylsilylene.' I n contrast to this, irradiation of t h e disilanes bearing a s-electron system on a silicon atom leads to isomerization involving migration of
lysilanes highly'depends on t h e structure a n d t h e substituents attached to silicon atoms. For example, irradiation of permethylcyclohexasilane with a low-pressure
(1) (a) Ishikawa, M.; Kumada, M. J. Chem. SOC.D 1970, 612. (b) Ishikawa, M.; Kumada, M. J. Chem. SOC.D 1971,489.
0276-733319212311-1593$03.00/0 0 1992 American Chemical Society
1594 Organometallics, Vol. 11, No. 4, 1992 a silyl group. Thus, irradiation of vinyl-substituted disilanes affords silenes arising from a 1,3-shift of a silyl group to the terminal carbon of the vinyl group in high yield~.~PSuch a photochemical 1 , 3 4 1 ~ shift 1 is not restricted to vinyldisilanes but is observed in aryldisilanes. In fact, pentamethylphenyldisilane undergoes photochemical isomerization involving a 1 , 3 4 1 ~shift 1 onto the ortho position of the phenyl ring to form a ~ i l e n e . In ~ the case of 2-phenylheptamethyltrisilane,however, both extrusion of silylene and the 1 , 3 4 1 ~shift 1 onto the phenyl ring occur ~ompetitively.~" We have also found that a 1,241~1 shift occurs in some cases. Phenylethynyldisilanes undergo photochemical isomerization involving the 1,2-silyl shift, leading to the formation of silacy~lopropenes.~~~ In these photolyses, silapropadienes arising from a 1 , 3 4 1 ~shift 1 are also produced as reactive intermediatesS6Similar photolysis of a phenylethenyldisilane affords a silacyclopropane and a silaindane, via a 1,241~1 ~ h i f t .It~is~ of ~ interest to us to investigate the photochemical behavior of 2-phenylethenyland 2,2-diphenylethenyl-substitutedtrisilanes and to learn which reaction, extrusion of the silylenes or isomerization accompanied by an intramolecular silyl shift, takes place in the photolysis of these compounds. In this paper, we report the unique photochemical behavior of 242phenylethenyl)-2-(trimethybilyl)hexamethyltrisilane(la), 2 4 2,2-diphenylethenyl)-2-(trimethylsilyl) hexamethyltrisilane (lb), and 2-(2,2-diphenylethenyl)-2-phenylhexamethyltrisilane (IC).
Results and Discussion As for the photolysis of (E)-(2-phenylethenyl)pentamethyldisilane reported previously,8 irradiation of (E)2- (2-phenylethenyl)-2-(trimethybilyl)hexamethyltrisilane (@)-la)with a low-pressure mercury lamp in hexane afforded an equilibrium mixture consisting of @)-la and (Z)-lain the ratio of 5 4 in the initial stage of the reaction. On prolonged irradiation, the E and 2 isomers decreased gradually without change of this ratio and two products, (E)-2-phenyl(trimethylsilyl)ethene ((E)-2a) and (2)-2phenyl(trimethylsily1)ethene ((2)-2a),were obtained in 5 and 2% yields, respectively, together with 11% of (E)-la and 8% of (Z)-la.9 The photolysis of @)-la in the presence of methanol gave neither the product arising from a silacyclopropanederivative nor the product derived from a silene intermediate, but the products (E)-2aand (Z)-2a were obtained in 10 and 4% yields, respectively. Although the formation of 2a clearly indicates that the photolysis of la involes the extrusion of bis(trimethylsilyl)silylene, no silylenemethanol adduct was obtained. A similar photolysis of (E)-la in the presence of 2,3-dimethylbutadiene, again, afforded no silylene adduct, but (E)-2a and (Z)-2awere isolated in 24 and 11% yields, respectively. (2) Ishikawa, M.; Fuchikami, T.; Kumada, M. J. Organomet. Chem. 1976, 117, C58. (3) Sakurai,H.; Kamiyama, Y.; Nakadaira, Y. J. Am. Chem. Soc. 1976, 98,7424. (4) Ishikawa, M.: Fuchikami, T.: Suaaya, _ . T.; Kumada, M. J. Am. Chem. Soc. 1975,97,5923. (5) (a) Ishikawa, M.; Nakagawa, K.; Ishiguro, K.; Ohi, F.; Kumada, M. J. Ormnomet. Chem. 1978. 152. 155. (b) Ishikawa. M.;. Ishiauro. M.: Kumada, M. J. Organomet: Chem. 1973,49, C71. (6) Ishikawa, M.; Fuchikami, T.; Kumada, M. J.Am. Chem. SOC.1977, 99, 245. (7) Sakurai, H.; Kamiyama, Y.; Nakadaira, Y. J.Am. Chem. SOC.1977, 99, 3879. (8) Ishikawa, M.; Fuchikami, T.; Kumada, M. J. Organomet. Chem. 1978, 149, 37. (9) The isolated 2 isomer was found to isomerize to the E isomer on standing for long times.
Kunai et al. Table I. Photolysis of Trisilanes at 254 nm trisilane (E)-la (E)-Ia (E)-la lb lb lb lb lb lb IC IC IC a
additive none MeOH DMB" none MeOH t-BuOH DMB isobutene PhMepSiH none DMB piperylene
time, h 15 15 15
70 15 10 20 8 20 6 6 8
oroduct. % (-??)-la, 11; (Z)-la, 8; (E)-2a,5; (2)-2a, 2 (E)-la, 10; (Z)-la,7; (E)-2a, 10; (Z)-2a, 4 (E)-la, 11; (Z)-la, 3; (E)-%, 24; (Z)-2a, 11 lb, 10; 2b, 10; 3b, 9; HMD,* 2 lb, 17; 2b, 16; 3b, 31 lb, 13; 2b, 17; 3b, 13 lb, 17; 2b, 37; 3b, 1 lb, 47; 2b, 17; 3b, 4 lb, 20; 2b, 15; 3b, 11 IC, 15; 2b, 19; 3c, 1; 4c, 17 IC, 13; 2b, 28; 3c,
