4092
J . Am. Chem. SOC.1988,110, 4092-4093
Acknowledgment. One of us, O.W.S. would like to thank I.A.E.S.T.E. for a summer studentship at the National Research Council. We thank Professor Jack Timberlake and an anonymous reviewer for helpful comments and Dr. Larkin Kerwin for a “President’s Award” that made this work possible. Registry NO.HZ, 1333-74-0; pF$C6H4OH, 402-45-9; p-CIC6H40H9 106-48-9; PhOH, 108-95-2; p-HOC6H,Bu-t, 98-54-4; p-MeOC6H40H, 150-76-5.
Synthesis, Characterization, and X-ray Crystal Structure of a Donor-Stabilized Bis(sily1ene)iron Complex Keiji Ueno, Hiromi Tobita, Mamoru Shimoi, and Hiroshi Ogino* Department of Chemistry, Faculty of Science Tohoku University, Sendai 980, Japan Received February 18, 1988
Silylene complexes have been proposed as reactive intermediates in a number of reactions’ and as products in a few reactions? but there has been no report on the X-ray crystal structure analysis of stable silylene complexes until recently. In 1987,two groups reported one after the other the syntheses and crystal structures of donor-stabilized silylene complexes: [(OC),Fe=Si(O-t(BPh4) (Cp’ Bu),.HMPT] and [Cp’(Me3P)2Ru=SiPh2.NCMe] = $-CsMe5)! We now report the first synthesis and X-ray cryspl structure determination of a donor-stabilized bis(sily1ene)iron complex. Recently, Pannell’s groupS and we6 independently observed an unusually fast alkyl scrambling between silicon atoms in the photoinduced conversion of CpFe(C0),SiR2SiR3 to CpFe(C0)*SiR3 ( R = alkyl, aryl). Silyl(sily1ene)iron intermediates were postulated as key intermediates of this reaction, but these were too unstable to isolate. Thus, our efforts have focused on searching substituents on silicon atoms which effectively stabilize the silyl(sily1ene)iron complexes, and we have finally found that these can be stabilized as donor-stabilized bis(sily1ene)iron complexes by introducing alkoxy groups. The starting complex Cp‘Fe(CO)2SiMe2SiMe(OMe)2 (1)’ was prepared as follows: Na[Cp’Fe(CO),] was allowed to react with CIMezSiSiMeClz,and then the product was treated with methanol and pyridine to give 1 and its isomer Cp’Fe(CO),SiMe(OMe)SiMe2(0Me) in 32% and 9% overall yields, respectively. Irradiation of 1 in C6D6or toluene (a. 0.1 M) with a medium pressure (1) (a) Ojima, I.; Inaba, S.; Kogure, T.; Nagai, Y. J. Organomet. Chem. 1973, 55, C7. (b) Okinoshima, H.; Yamamoto, K.; Kumada, M. J. Am. Chem. SOC.1972, 94, 9263. (c) Sakurai, H.; Kamiyama, Y.; Nakadaira, Y. Ibid. 1977, 99, 3879. (d) Nakadaira, Y.; Kobayashi, T.; Sakurai, H. J. Organomet. Chem. 1979,165,399. (e) Sakurai, H.; Kamiyama, Y.; Nakadaira. Y. Ibid. 1980. 184. 13. t t l Thum. G.: Malisch. W. Ibid. 1984. 264. CS. (g) Kang, H.; Jacobson, D: B.; Shin; S. K.;Beaudhamp, J. L.;Bowere; M. T. J. Am. Chem. SOC.1986, 108, 5668. (2) (a) Schmid, G.; Welz, E. Angew. Chem., Int. Ed. Engl. 1977,16,785. (b) Sakurai, H.; Kamiyama, Y.; Nakadaira, Y. Angew. Chem., Int. Ed. Engl. 1978.17.674. Prof. Sakurai informed us that the silylene complex reported previously was in fact a disilanyliron complex. Detaiis will be reported elsewhere. (3) Zybill, C.; Muller, G. Angew. Chem., Int. Ed. Engl. 1987, 26, 669. (4) Straus, D. A,; Tilley, T. D.; Rheingold, A. L.;Geib, S. J. J. Am. Chem. SOC.1987, 109, 5872. (5) Pannell, K. H.; Cervantes, J.; Hernandez, C.; Cassias, J.; Vincenti, S. Organometallics 1986, 5, 1056. (6) Tobita. H.: Ueno. K.: Onino. H. Chem. Left. 1986. 1777 (7) For 1: “ H N M R ’ ( 9 0 ’ M k , &De) 6 3 5 0 ( s , 6 H, OMe), 1.62 (s, 15 H, Me of Cp’), 0.72 (s, 6 H, Si-Me), 0.41 (s, 3 H, Si-Me); ‘)C NMR (22.5 MHz, C6D6) 6 217.8 (CO), 95.2 (C?’ ring carbon), 50.1 (OMe), 9.8 (Me of Cp’), 3.5 (Si-Me), -2.2 (Si-Me); Si NMR (17.8 MHz, C$6) d 10.7, 4.6; IR (C6D6)v(C0) 1920 vs, 1972 vs cm-I; Anal. Calcd for C,,H,FcO,Si,: C, . .. 49.75; H, 7.39. Found: C, 49.74; H, 7.35.
Figure 1.
ORTEP view of 2 with thermal elipsoids at 30% probability level. Selected distances (A) and angles (deg): Fe-Si(l), 2.222 (3); Fe-Si(2), 2.207 (3); Fe-C(l), 1.676 (11); Si(l)-C(S), 1.88 (2); Si(l)-C(6), 1.88 (2); Si(1)-0(2), 1.793 (9); Si(2)-0(2), 1.799 (8); Si(2)-0(3), 1.632 (9); Si(2)-C(4), 1.94 (2); 0(2)-C(2), 1.45 (2); 0(3)-C(3), 1.41 (2); 0(l)-C(l), 1.198 (14); Si(l)--Si(2), 2.622 (4); Fe-0(2), 2.962 (7); 0(1)-C(3), 3.33 (2); C(4).-C(14), 3.59 (2); C ( 6 ) 4 ( 1 3 ) , 3.54 (2); Si(I)-Fe-Si(2), 72.6 (1); Fe-Si(l)-0(2), 94.5 (3); Fe-Si(2)-0(2), 94.8 (3); Si(l)-0(2)-Si(2), 93.8 (4); Fe-Si(l)C(S), 123.1 (5); Fe-Si(1)-C(6), 123.6 (6); C(S)-Si(I)-C(6), 105.8 (7); Fe-Si(2)-0(3), 126.9 (4); Fe-Si(2)C(4), 127.2 ( 5 ) ; 0(3)-Si(2)
