2153
Organometallics 1995, 14, 2153-2155
Synthesis and Structure of a Dinuclear q l:q2-p2=Butenynyl Complex Which Catalyzes Di- and Trimerization of Ferrocenylacetylene at the Thiolate-Bridged Diruthenium Center Hiroyuki Matsuzaka,? Yukihiro Takagi, Youichi Ishii, Masayuki Nishio, and Masanobu Hidai* Department of Chemistry and Biotechnology, The University of Tokyo, Hongo, Tokyo 113, Japan Received January 12, 1995@ Summary: Treatment of [Cp*RuCl(p2-SPrJ)zRuCp*I[OlT/ (1; Cp* = q5-C&ie5, OTf = OSO2CF3) with H C W F c (Fc = ferrocenyl) at room temperature afforded the dinuclear butenynyl complex [Cp*Ru(q1:4-prC(=CHFc)C=CFc}(p2SPrJ)zRuCp*l[OlT/(4a), the molecular structure of which has been determined by X-ray diffractionanalysis of the corresponding BPh4- salt 4b. Complex 4a is an effective catalyst for di- and trimerization of the alkyne to yield the head-to-head Z dimer CHFc=CHCWFc (5) and the linear Z,Z trimer CHFc=CHCFc=CHC=CFc (6). Multisite interactions between a substrate molecule and more than one adjacent metal center can facilitate activation and transformation of the substrate, which offers a promising approach to new types of catalytic pr0cesses.l In a recent study on transition-metalsulfur cluster compounds, we have shown that a series of dinuclear Cp*Ru-thiolate complexes (Cp* = q5-C5Me5)2-4provide well-defined bimetallic reaction sites for unique transformations of alkyne^,^ organic halides,2c and hydrazines.6 In a previous paper, we described
-
facile coupling of HCGCR (R = CCH(CH2)3CH2, Toll on [Cp*RuC1@2-SPri)2RuCp*l[OTfl (1; OTf = OS02CF3), affording the five-membered metallacycles 2 and + Present address: Department of Chemistry, Tokyo Metropolitan University, Minami-osawa, Tokyo 192-03, Japan. e Abstract published in Advance ACS Abstracts, April 15, 1995. (1)(a)Suss-Fink,G.; Meister, G. Adu. Organomet. Chem. 1993,35, 41 and references cited therein. (b) Gates, B. C., Guzci, L., Knozinger, V. H., Eds. Metal Clusters in Catalysis: Elsevier: Amsterdam, 1986. (2)(a) Dev, S.;Imagawa, K.; Mizobe, Y.; Cheng, G.; Wakatsuki, Y.; Yamazaki, H.; Hidai, M. Organometallics 1989,8, 1232.(b) Dev, S.; Mizobe, Y.; Hidai, M. Inorg. Chem. 1990,29,4797.( c ) Takahashi, A.; Mizobe, Y.; Matsuzaka, H.; Dev, S.; Hidai, M. J. Organomet. Chem. 1993,456,'243.(d) Matsuzaka, H.; Ogino, T.; Nishio, M.; Hidai, M.; Nishibayashi, Y.; Uemura, S. J . Chem. SOC.,Chem. Commun. 1994, 223. (e) Hidai, M.; Mizobe, Y.; Matsuzaka, H. J . Organomet. Chem. 1994,473,1. (3)Some dinuclear CpRu and Cp*Ru complexes have been recently reported. See: (a)Kuhlman, R.; Streib, K; Caulton, K G. J. Am. Chem. SOC.1993,115,5813.(b) Rauchfuss, T. B.; Rodgers, D. P. S.; Wilson, S. R. J. Am. Chem. SOC.1986,108,3114. (c) Loren, S.D.; Campion, B. K.; Heyn, R. H.; Tilley, T. D.; Bursten, B. E.; Luth, K. W. J . Am. Chem. SOC.1989,llI , 4712.(d) Suzuki, H.; Omori, H.; Lee, D.-H.; Yoshida, Y.; Fukushima, M.; Tanaka, M.; Moro-oka, Y. Organometallics 1994, 13,1129.(e) Knox, S.A. R. J . Organomet. Chem. 1990,400,255and references cited therein. (D Kolle, U.; Kang, B.-S.; Thewalt, U. Organometallics 1992,11, 2893.(g) Chang, J. C.; Bergman, R. G. J . Am. Chem. SOC.1987, 109,4298. (h) Hubbard, J. L.; Momeau, A.; Burns, R. M.; Zolch, C. R. J . Am. Chem. SOC.1991,113,9176. (4)For pertinent examples of Ru-sulfur complexes, see: (a)Houser, E. J.; Amarasekera, J.; Rauchfuss, T. B.; Wilson, S. R. J . Am. Chem. SOC.1991, 113,7440.(b) Amarasekera, J.; Rauchfuss, T. B.; Wilson, S. R. J . Chem. SOC.,Chem. Commun. 1989,14.( c ) Koch, S.A,; Millar, M. J . Am. Chem. SOC.1983,105,3362.(d) Millar, M. M.; OSullivan, T.; Vries, N.; Koch, S. A. J . Am. Chem. SOC.1986,107,3714. (e) Shaver, A,; Plouffe, P.-Y.; Lilles, D. C.; Singleton, E. Znorg. Chem. 1992,31, 997.(D Homig, A.; Englert, U.; Kolle, U. J . Organomet. Chem. 1994, 464,C25.
3.7 These reactions have been believed to proceed via 1
-
U 2
3
a vinylidene-alkynyl combination pathway at the diruthenium enter.^^^^^^ However, no intermediates could be detected in these conversions even a t low temperature with a limited amount of alkynes. We report herein the isolation and characterization of the dinuclear butenynyl complex [Cp*Ru{q1:q2-p2-C(=CHFc)C=CFc}@2-SPri)2RuCp*l[OTfl(4a; Fc = ferrocenyl), which corresponds to a key intermediate of the above coupling reactions, and its unique catalytic activity for linear diand trimerization of HC=CFc. Treatment of 1 with 6 equiv of HCWFc in CHzClz at room temperature gave the dinuclear butenynyl complex 4a in 83%yield (eq 11, which was obtained as a dark brown crystalline solid;gits corresponding BPbsalt 4b has been fully characterized by X-ray crystallography (Figure 1).l0The most characteristic feature of its structure is the bridging butenynyl moiety formed by head-to-head coupling of two HCWFc molecules on the diruthenium-thiolate template. The two Ru atoms (5) (a) Matsuzaka, H.; Mizobe, Y.; Nishio, M.; Hidai, M. J . Chem. SOC.,Chem. Commun. 1991, 1011. (b) Nishio, M.; Matsuzaka, H.; Mizobe, Y.; Hidai, M. J. Chem. SOC.,Chem. Commun. 1993,375.(c) Nishio, M.; Matsuzaka, H.; Mizobe, Y.; Tanase, T.; Hidai, M. Organo(d) Matsuzaka, H.; Hirayama, Y.; Nishio, M.; metallics 1994,13,4214. Mizobe, Y.; Hidai, M. Organometallics 1993,12,36.(e) Matsuzaka, H.; Koizumi, H.; Takagi, Y.; Nishio, M.; Hidai, M. J . Am. Chem. SOC. 1993,115,10396. (6)Kuwata, S.;Mizobe, Y.; Hidai, M. Inorg. Chem. 1994,33,3619. (7) Matsuzaka, H.; Takagi, Y.; Hidai, M. Organometallics 1994,13, 13.The structure 1 is more appropriate than the structure Ru@&l)Ru proposed in the previous paper,7 because the 'H NMR spectrum taken at -50 "C exhibited resonances at 6 1.59 and 1.63 assigned to two nonequivalent Cp* methyl groups. (8) Formation of mononuclear butenynyl complexes by vinylidenealkynyl combination has been observed. See: (a) Hughes, D. L.; Jimenez-Tenorio, M.; Leigh, G. J.; Rowley, A. T. J . Chem. SOC.,Dalton Trans. 1993,3151.(b) Field, L. D.; George, A. V.; Purches, G. R.; Slip, I. H. M. Organometallics 1992,11,3019.( c ) Bianchini, C.; Peruzzini, M.; Zanobini, F.; Frediani, P.; Albinati, A. J . Am. Chem. SOC.1991, 113,5453. (d) Wakatsuki, Y.; Yamazaki, H.; Kumegawa, N.; Satoh, T.; Satoh, J. Y. J . Am. Chem. SOC. 1991, 113, 9604. (e) Jia, G.; Rheingold, A. L.; Meek, D. W. Organometallics 1989,8,1378. (0Gotzig, J.; Otto, H.; Werner, H. J . Organomet. Chem. 1985,287, 247. (g) Dobson, A.;Moore, D. S.; Robinson, S. D. J . Organomet. Chem. 1979, 177,C8.
0276-733319512314-2153$09.00/0 0 1995 American Chemical Society
Communications
2164 Organometallics, Vol. 14, No. 5, 1995
c33 c34
C3 1
Figure 1. ORTEP drawing of the cationic part of complex 4b.
7
OTf-
e*s + /CP
CP;
+
S Pr'
C'
Pr'
CH2Cl2
HCECFc 6 eqt1IV
r. t.
Fc ferrocenyl 1
4a (83%)
form an almost planar ring system with C(l), C(2), and C(3). The distances between Ru(1) and C(1) (2.40(1)A) and C(2) (2.384(10) A) are longer in comparison with the metal-carbon lengths in common n-alkyne complexes.ll This is reflected in the relatively short C(1)C(2) distance of 1.22(1) A. Although several mononu(9) To a CHzClz (20 mL) solution of 1 (502 mg, 0.622 mmol) was added HC=CFc (0.63 mL, 3.7 mmol), and the reaction mixture was stirred overnight at room temperature. After removal of the solvent, the resultant solid was washed with hexane ( 5 mL x 3) and recrystallized from CHzCldether ( 5 d l 5 mL) to give 4a as dark brown crystals (618 mg, 0.519 mmol); yield 83%. 'H N M R (CDCls): 6 5.51 ( 8 , lH, vinyl), 4.32, 4.27, 4.26, 4.19 (t, 2H each, J = 1.9 Hz,C6HJ, 4.09, 3.73 ( 8 , 5H each, Cp), 3.99 (sep, 2H, J = 6.7 Hz,SCHMeZ), 1.87, 1.46 (6, 15H each, Cp*), 1.68, 1.67 (d, 6H each, J = 6.7 Hz, SCHMe2). A small amount of dimer 5 and trimer 6 (eq 2) were also observed in the reaction mixture. Single crystals of 4b suitable for X-ray structural analysis were prepared by recrystallization from CHnClz/hexane after the anion metathesis of 4a by BPL-.
clear butenynyl complexes have appeared in the literature,s 4 is, to the best of our knowledge, the first example of a well-characterized dinuclear butenynyl complex and sheds light on the mechanism of alkyne coupling reactions involving vinylidene-alkynyl combination at the thiolate-bridged diruthenium site.12 Complex 4a has proved to be an efficient catalyst for linear di- and trimerization of HC=CFc under mild conditions (eq 2: in ClCH&H2C1,60 "C, 30 h, HCsCFc: 4a = 20:l).13 A mixture of the head-to-head dimer S and the linear trimer 6 was produced with high regioselectivity and stereoselectivity, which were isolated in 62% and 32% yields, respectively, and spectroscopically (10)Crystal data: Pi (triclinic), a = 15.005(2) A, b = 17.693(3) A, c = 15.020(2)A, a = 95.95(1)", B = 107.53(1)",y = 98.49(1)", V = 3714(1)A, 2 = 2, R(R,) = 5.4% (4.4%) for 5606 reflections (111 > 3dO). Bond distances (A) and angles (deg): Ru(l)-Ru(2),2.767(1); Ru(l)-C(l), 2.40(1); Ru(l)-C(2), 2.384(10); Ru(2)-C(3), 2.091(10); C(l)-C(2), 1.22(1); C(2)-C(3), 1.46(1); C(3)-C(4), 1.33(1); R~(2)-Ru(l)-C(l), 97.1(3); Ru(2)-Ru(l)-C(2), 67.9(2); Ru(l)-R~(2)-C(3), 78.4(3); Ru(1)C(l)-C(2), 74.6(7);R~(l)-C(l)-c!(5), 124.6(8);C(2)-C(l)-C(5), 160(1); R~(l)-c(2)-C(l), 75.8(7);Ru(l)-C(2)-C(3) 105 8(7) C(l)-C(2)-C(3) 172(1); Ru(2)-C(3)-C(2), 107.8(7); Ru(2)-&(3)-&4), 129.8(8); C(3)-C(4), 122.3(10); C(3)-C(4)-C(15), 130(1). (11)Ittel, S. D.; Ibers, J. A. Adu. Orgunomet. Chem. 1976, 14, 33. (12) Several coupling reactions between the vinylidene ligand and the organic moiety at mononuclear sites have also been reported. See: (a)Wiedemann, R.; Steinert, P.; Schafer, M.; Werner, H. J. Am. Chem. SOC.1993, 115, 9864. (b) Selnau, H. E.; Merola, J. S.J. Am. Chem. SOC.1991,113, 4008. (13)A solution of HClCFc (303 mg, 1.44 mmol) and 4a (82 mg, 0.069 mmol; 5 mol % of the alkyne) in ClCHzCHzCl(5 mL) was stirred a t 60 "C for 30 h. After removal of the solvent, the resultant solid was chromatographed on silica gel with benzenehexane (Wl).The first band (yellow) contained unreacted HClCFc (19 mg, conversion 94%). Solvents were evaporated from the second (orange) and the third (orange) bands, from which dimer 5 (188 mg) and trimer 6 (96 mg) were obtained, respectively.
Communications HC=CFc
Organometallics, Vol. 14, No. 5, 1995 2155
4a (5 mol%)
Scheme 1
CICH2CH2CI 60 O C , 30 h
[RuI-Nl
+n
P 7
Fc7y +
Fc
(2)
Fc
4a
HCECFc
5 (62%)
6 (32%)
characte14zed.l~ Further, the structure of 6 has been unequivocally determined by X-ray ana1y~is.l~ Particularly interesting is the formation of the linear trimer 6, which has never been observed in oligomerization with mononuclear complex catalysts.16 No byproducts such as cyclic oligomers were detected, and 4a was recovered from the reaction solution in high yield. These results strongly suggest that the reaction proceeds at the diruthenium core, which remains intact during the catalysis. Klein et al. recently reported the highly selective linear trimerization of H C W P h in the (7) to presence of triangulo-Co3CU3-H)CU2-C0)3(PMe3)6 give the E,E linear trimer Ph(PhC=C)C=CHCH=CHPh.17 However, it was not certain whether a tricobalt derivative of 7 or a mononuclear species is the active catalyst. Furthermore, it should be noted that the configuration of the latter trimer is essentially different from that of 6. A plausible mechanism for the formation of dimer 5 is shown in Scheme 1. The butenynyl complex 4a would first react with incoming HCWFc molecules to liberate 5 and form the monoalkynyl-alkyne intermediate 8. (14) 5: yield 62%; 'H NMR (CDCls) 6 6.44, 5.58 (d, 1H each, J = 11.5 Hz, alkenyl), 4.87,4.52,4.33,4.27(t, 2H each, J = 1.9 Hz,CSH~), 4.28. 4.18 ( 6 . 5H each. CD):13C NMR (CDClQ)6 137.2. 104.6.93.9.85.7. --81.1; 71.0, 69.8, 69.4,'66.2, 69.1, 68.8, 66.O;'MS(EI)"lz 420 (M+). 61 yield 32%; lH NMR (CDC13) 6 6.26 (d, lH, J = 12.0 Hz, vinyl), 6.21 (dd, lH, J = 12.0, 1.0 Hz, vinyl), 5.94 (d, lH, J = 1.0 Hz, vinyl), 4.97, 4.51, 4.44, 4.36, 4.26, 4.21 (t,2H each. J = 1.7 Hz. C5H.A 4.28. 4.23. 4.13 (s. 5H each. CUI: 13C NMR tCDC1.4 6 145.0. 128.-6.127.2. 105.2. 95.3,86.5,82.8,80.6,'70.9, 70.0,69.9,69.6,69.4,69.2,69.0,68.8,68.6; 66.4; MS (EI)m l z 630(M+). (15) Crystal data: P2dc (monoclinic), a = 11.623(1)A, b = 18.341(2) A, c = 12.814(1)A, 9, = 91.855(7)", V = 2730.1(4)As, 2 = 4, R (Rw) = 4.9% (2.3%)for 2330 reflections (111>3a(I)). (16) Oligomerization of HCWFC by using (PPh&Ni(C0)2 gave a mixture of the head-to-head dimer 5, the acyclic branched trimer CHFc=CHC(C=CFc)=CHFc, and 1,2,4-triferrocenylbenzene:Pittman, C. U.,Jr.; Smith, L. R. J. Orgunomet. Chem. 1975, 90, 203. (17) Klein, H.-F.; Mager, M.; Isringhausen-Bley, S.; Florke, U.; H a u p t , H.-J. Organometallics 1992, 11, 3174. I
z 9
Fc+\
f
8
n [Rul-[Ru]
C; P
,CP'
s \ =< - *S, Pt
Pr'
Fc = ferrocenyl
Complex 8 is then converted into the vinylidenealkynyl intermediate 9, which is further transformed back to the starting compound 4a. If the trans migratory insertion of two HCGCFCmolecules into the Rualkynyl bond in 8 proceeds at the diruthenium site, the linear trimer 6 may be formed. However, we must await further investigations to elucidate a detailed reaction mechanism.
- 7
Acknowledgment. The Ministry of Education, Science and Culture of Japan is gratefully acknowledged for support of this research. Supplementary Material Available: Text giving experimental details, including results of elemental analyses, and tables of crystal data and data collection parameters, atomic coordinates, anisotropic thermal parameters, and bond distances and angles for 4b and 6 (27 pages). ordering information is given on any current masthead page.
OM950024S
