Organometallics 1995, 14, 3741-3745
3741
Synthesis and Nucleophilic Substitution of Highly Chlorinated Arene (~5-Pentamethylcyclopentadienyl)ruthenium n-Complexes Alexa A. Dembek" and Paul J. Fagan DuPont Central Research and Development, Experimental Station, Wilmington, Delaware 19880-0328 Received March 15, 1995@ Facile synthesis of Cp*Ru+ (Cp* = pentamethylcyclopentadienyl) n-complexes of highly electron deficient aromatics, including 1,3,5-trichloro-, 1,2,4,54etrachloro-, pentachloro-, and hexachlorobenzene, is accomplished by the ligand exchange reaction with Cp*Ru(CH&N)3+S03CF3- in polar solvents under mild reaction conditions. The extraordinary activating ability of the Cp*Ru+ moiety is demonstrated by rapid and quantitative nucleophilic substitution reactions of the 1,3,5-tri- and 1,2,4,5-tetrachlorobenzenen-complexes with potassium phenoxide, thiophenoxide, 4-aminophenoxide, 4-chlorophenoxide, and 4-fluorophenoxide. This methodology allows syntheses of highly substituted and functionalized aromatic compounds. Nucleophilic displacement reactions on transition metal n-complexes of haloaromatics provides entry to novel functionalized arenes,' monomers that are inaccessible by traditional organic methodology2and metalcontaining oligomers3 and polymer^.^ Typically, the aromatic halide is a mono- or dichlorobenzene derivative, and the transition metal activating group is Cr(co)~, CpFe+ (Cp = cyclopentadienyl), Mn(C0)3+,CpRu+, or Cp*Ru+ (Cp* = pentamethyl~yclopentadienyl).~ However, facile solution routes to metallo n-complexes of more highly electron deficient arenes, such as aromatics with three or more halogen substituents, are largely unknown due to the decreased coordinating ability of the arene. Considerable attention has recently been directed toward solution synthesis of perhalogenated y5-cyclopentadienyl complexes due to their decreased susceptibility t o oxidative decomposition.6 In contrast, efforts to prepare perhalogenated y6-arene complexes have published in Advance ACS Abstracts, June 15, 1995. (1)(a) Pearson, A. J.; Park, J . G.; Yang, Y. S.; Chuang, Y. J. Chem. SOC.,Chem. Commun. 1989, 1363. (b) Pearson, A. J.; Park, J. G.; Zhu, P. Y. J. Org. Chem. 1992, 57, 3583. ( c ) Pearson, A. J.; Zhu, P. Y.; Youngs, W. J.; Bradshaw, J. D.; McConville, D. B. J. Am. Chem. Soc. 1993,-115, 10376. (2) (a) Pearson, A. J.: Gelormini, A. M. Macromolecules 1994. 27, 3675. (b) Pearson, A. J.;Gelormini, A. M. J. Org. Chem. 1994,59,4561. ( 3 ) ( a ) Abd-El-Aziz, A. S.; Schriemer, D. C.; de Denus, C. R. Organometallics 1994, 13, 374. (b) Abd-El-Aziz, A. S.; de Denus, C. R. J . Chem. SOC.,Chem. Commun. 1994, 663. (4) (a) Segal, J. A. J . Chem. SOC.,Chem. Commun. 1985, 1338. (b) Dembek, A. A.; Fagan, P. J.; Marsi, M. Macromolecules 1993,26,2992. ( c ) Dembek, A. A,; Marsi, M. U.S.Patent 5350832, 1994. (d) Dembek, A. A.; Fagan, P. J.; Marsi, M. Polym. Mater. Sci. Eng. 1994, 71, 158. (e) Percec, V.; Okita, S. J. Polym. Sci., Part A 1993, 31, 923. (5) For transition metal activated nucleophilic aromatic substitution, see: (a)Pearson, A. J. Metallo-Organic Chemistry; Wiley: New York, 1985; Chapter 9 and references therein. (b)Watts, W. E. The Organic Chemistry of Metal-Coordinated Cyclopentadienyl and Arene Ligands Comprehensive Organometallic Chemistry; Wilkinson, G., Stone, F. G. A,, Abel, E., Eds.; Pergamon Press: Oxford, 1982; Vol. 8, Chapter 59 and references cited therein. (6) (a) Curnow, 0. J.; Hughes, R. P. J. A m . Chem. SOC.1992, 114, 5895. (b) Winter, C. H.; Han, Y. H.; Heeg, M. J. Organometallics 1992, 11,3169. ( c )Winter, C. H.; Han, Y.H.; Ostrander, R. L.Angew. Chem., Int. Ed. Engl. 1993,32, 1161. (d) Han, Y. H.; Heeg, M. J.; Winter, C. H. Organometallics 1994, 13, 3009.
been limited primarily to metal atom ~ y n t h e s i s .One ~ recent exception is a report on a solution lithiatiod chlorination of (7,76-C&C1)Cr(C0)3 to afford the homologs (y6-CsHs-nC1,)Cr(CO)3( n = 1-6), including (y6C&16)Cr(C0)3.8 We now report the discovery that the cationic Cp*Ru+ moiety overcomes the challenges of complexation to highly electron deficient aromatics and provides a versatile organometallic tool for construction of highly functionalized arene architecture^.^ We illustrate this methodology with the facile synthesis of Cp*Ru+ complexes of highly electron deficient aromatics, including trichloro-, tetrachloro-, pentachloro-, and hexachlorobenzene. Remarkably, the trichloro- and tetrachlorobenzene n-complexesreadily undergo rapid and quantitative nucleophilic substitution reactions which allow syntheses of highly substituted and functionalized aromatic compounds and offer opportunities for syntheses of novel organometallic dendrimer architectures.1°
e Abstract
Results and Discussion Synthesis and Characterization of Cp*Ru+ n-Complexes. The outstanding mcomplexing ability of the Cp*Ru+moietyll allows a surprisingly efficient and direct solution synthesis of highly electron deficient arene n-complexes based on tri-, tetra-, penta-, and hexachlorobenzene. These unique bonding features of (7) (a)Trost, H. K. Tailor-Made Metal-Organic Compounds: Technology and Chemistry of Metal Atom Synthesis; VDI Verlag: Diisseldorf, Germany, 1992. (b) Blackborow, J. R. Metal Vapour Synthesis in Organometallic Chemistry; Springer-Verlag: New York, 1979. ( c ) McGlinchey, M. J. In The Chemistry of the Metal-Carbon Bond; Hartley, F. R., Patai, S.,Eds.; Wiley: New York, 1982; p 539. (d) Marr, G.; Rockett, B. W. Ibid., p 463. (e) Timms, P. L. J . Chem. Educ. 1972, 49, 782. (8) Gassman, P. G.; Deck, P. A. Organometallics 1994, 13, 1934. (9) Dembek, A. A. U S . Patent 5,386,044, 1994. (10)(a) Moulines, F.; Djakovitch, L.; Boese, R.; Gloaguen, B.; Thiel, W.; Fillaut, J. L.; Astruc, D. Angew. Chem., Int. Ed. Engl. 1993, 32, 1075. (b) Liao, Y. H.; Moss, J. R. J. Chem. Soc., Chem. Commun. 1993, 1774. (c) Alonso, B.; Cuadrado, I.; Moran, M.; Losada, J. J. Chem. SOC., Chem. Commun. 1994, 2575.
0276-733319512314-3741$09.0010 0 1995 American Chemical Society
Dembek and Fagan
3742 Organometallics, Vol. 14,No. 8, 1995 Scheme 1
Scheme 2 CI
CI
\
Cp'Ruf(CH3CN),, c i n cCIl CI
THF
S03CFi
*
RU+C~'(OT~')
clq;; 2
5, X = O , R = H 6. X = S . R = H
CI
RU+C~'(OT~') Cl&c!
Cp'Rd(CH3CN),,
CI
CI
Dioxane
SO3CFi
*
CI c1*3
CI RU+C~'(OT~')
CI
CI \
CI
CI
Dioxane
RU+C~'(OT~)
2
R R
the Cp*Ru+moiety are further accentuated considering that the corresponding Cr(C0)3, CpFe+, or Mn(C0)3+ n-complexes are inaccessible by direct solution reaction of the metal fragment precursor and the electron deficient aromatic. Synthesis of Cp*Ru+ n-complexes 1-4 is accomplished simply by the ligand exchange reaction of [C~*RU(CH~CN)~I+SO~CF~with an excess of the corresponding multichloroaromatic in polar solvents under mild reaction conditions (see Scheme 1). The tri- and tetrachlorobenzene Cp*Ru+ derivatives 1 and 2 are prepared in THF at 66 "C, while the more strongly electron deficient penta- and hexachlorobenzene Cp*Ru' derivatives 3 and 4 are prepared in dioxane at 85 "C. Unoptimized reactions afford complexes 1-3 in good yield (62%-88%) and 4 in moderate yield (42%). The yields can be increased substantially if very large excesses (6-15 equiv) of the chloroaromatic are used. IH and 13C NMR spectra of compounds 1-4 confirm the Cp*Ru+ n-complexation. Specifically, lH NMR analysis shows a singlet resonance with characteristic upfield shifts for the coordinated arene in the range 7.21-7.81 ppm. Singlet resonances for the methyl group of the Cp* ligand appear in the range 1.88-1.65 ppm. A progressive downfield shift in the complexed arene resonance and an upfield shift in the methyl group resonance of the Cp* ligand are detected in both the lH and 13CNMR spectra as the chloro substitution on the aromatic ring increases in the series 1-4. Positive-ion fast atom bombardment (FAB) mass spectral analyses and elemental microanalyses provide additional confirmation of the product structures. Although the focus of this manuscript is on Cp*Ru+ n-complexation of chloroaromatic derivatives, we have also recently prepared the corresponding 1,3,5-tri-, 1,2,4,5-tetra-, and pentasubstituted fluorobenzene derivatives by ligand exchange with Cp*Ru(CH3CN)3+S03CF3-. The synthesis, characterization, and (11) (a) Fagan, P. J.; Ward, M. D.; Caspar, J. V.; Calabrese, J. C.; Krusic, P. J. J . Am. Chem. Soc. 1988,110,2981. (b) Fagan, P.J.;Ward, M. D.; Calabrese, J. C. J . Am. Chem. Soc. 1989,I l l , 1698.( c ) Gill, T. P.; Mann, K. R. Organometallics 1982,1 , 485.(d) Glatzhofer, D. T.; Liang, Y . ;Khan, M. A,; Fagan, P. J. Organometallics 1991,10, 833. (e) Moriarty, R.M.; Gill, U. S.; Ku, Y . Y . J. Organomet. Chem. 1988, 350,157.(D Glatzhofer, D. T.; Liang, Y.; Funkhouser, G. P.; Khan, M. A. Organometallics 1994,13, 315.
e
x ~
,X X
O
R ~
10 X = O , R = H 11:X=S,R=H 12, 13, X X ==O0,, ~R R= C NH2 I R 14, X = O , R = F
RU+C~'(OT~)
reactivity of these fluoroarene n-complexes will be presented separately.12 Nucleophilic Substitution of Cp*Ru+n-Complexes. Investigation of nucleophilic displacement reactions of n-arenes 1-4 demonstrated the extraordinary activating ability of the Cp*Ru+ moiety. Surprisingly, triand tetrachlorobenzene n-complexes 1 and 2 undergo facile and quantitative nucleophilic displacement with preformed potassium salts of phenols or thiophenols in polar solvents under extremely mild reaction conditions. For example, reaction of [Cp'Ru(l;16-1,3,5-trichlorobenzene)l+S03CF3- (1) with potassium phenoxide or thiophenoxide (1.1equiv/C-C1 bond) in THF, CH3CN, or DMSO solvent affords the trisphenoxy or tristhiophenoxy derivatives 5 and 6 (see Scheme 2). In a similar manner, reaction of [Cp*Ru(l;16-l,2,4,5-tetrachlorobenzene)l+S03CF3-(2) with potassium phenoxide or thiophenoxide affords the tetrakisphenoxy or tetrakisthiophenoxy derivatives 10 and 11. These reactions proceed rapidly to quantitative conversion at 25 "C as determined by IH NMR spectroscopy using THF-&, CH3CNd3, or DMSO-ds as the reaction solvent. Reactions of penta- and hexachlorobenzene n-complexes 3 and 4 with potassium phenoxide or thiophenoxide afford a mixture of partially substituted products under mild reaction conditions. Note that the pentachlorobenzene n-complex 3 does undergo complete C-C1 substitution under forcing reaction conditions (CH3CN-d3, 75 "C, 16 h), as detected by 'H NMR. Challenging C-C1 bond displacement on compounds 3 and 4 is likely due to a combination of factors, including (i) diminished ability of the Cp*Ru+ moiety to activate the remaining C-C1 bond(s) in the presence of multiple phenoxy or thiophenoxy groups on the aromatic ring and (ii) steric hinderance. Alkoxide or thioalkoxide nucleophiles may be more suitable candidates for displacement reactions on platforms 3 and 4. Nucleophilic substitution of tri- and tetrachlorobenzene platforms 1 and 2 with potassium salts ofparasubstituted phenols offer new opportunities for synthesis of highly functionalized aromatic molecules. Scouting (12)Dembek, A. A.; Fagan, P. J. Manuscript in preparation.
Synthesis and Substitution of (q5-Cp*Ru) n-Complexes reactions were initially carried out in deuteriated solvents (THF-ds,CH&N-d3 ,and DMSO-& ) to monitor the extent of reaction by 'H NMR spectroscopy. As anticipated, the electronic characteristics of the para substituent correlate with the extent of reaction. Electron-donating substitutents enhance the nucleophilic character of the phenoxide and therefore facilitate nucleophilic displacement while strong electron-withdrawing substituents retard reactivity. Similar reactivity trends are anticipated for the corresponding substituted potassium thiophenoxides. Specifically, Cp*Ru+ n-complexes 1 and 2 undergo complete C-C1 bond substitution with potassium 4-amino-, 4-chloro-, and 4-fluorophenoxide to afford fully derivatized products 7-9 and 12-14, respectively (Scheme 2). The details of the syntheses are in the Experimental Section. In IH NMR scouting experiments, a variety of phenoxides with electron rich substituents in the ortho-, meta-, and para-positions afford complete nucleophilic substitution (additional examples include alkyl, aryl, alkoxy, and aryloxy substituents), illustrating the versatility of this methodology. In contrast to the electron rich phenoxides, reactions of 1 and 2 with nucleophiles containing strong electronwithdrawing groups afford no chloro displacement using standard reaction conditions. Specific examples include potassium 4-cyano-, 4-(trifluoromethyl)-, 4-nitro-, 3-nitro-, and perfluorophenoxide, and the potassium salts of 2-hydroxy- and 4-hydroxypyridine. Under forcing conditions (long reaction time, high temperature, and large excess of potassium aryloxide), reactions with potassium 4-cyano- and 4-(trifluoromethy1)phenoxide nucleophiles are slow and incomplete, and mixtures of starting material and partially substituted products are detected by lH NMR. Compounds 5-14 are isolated as air and moisture stable white solids in good yield (68%-96%). In all cases, the substitution reactions are quantitative by lH NMR, however, the isolated yields are always lower than 100% due t o losses during product isolation and purification. Purification requires an aqueous extraction to remove the potassium chloride generated during reaction as well as excess potassium alkoxide or thioalkoxide. Since the cationic Cp*Ru+ complexes are partially water soluble, product losses during purification are unavoidable. In general, the Cp*Ru+complexes are fully soluble in polar organic solvents. lH and 13C NMR spectra, positive-ion FAB mass spectral analyses and elemental microanalyses of Cp*Ru+ products 5- 14 confirm complete nucleophilic substitution (see Experimental Section). Compound 5 is representative of the series 5-14. The lH NMR spectrum of 5 shows a singlet resonance for the Cp*Ru+ n-complexed aromatic at 6.27 ppm, which is an upfield shift from the singlet resonance of the trichlorobenzene n-complex 1 a t 7.21 ppm. The resonances of the phenoxy substituents are in the range 7.49-7.20 ppm and the methyl group of the Cp* ligand is a singlet resonance at 1.98 ppm. The 13C NMR spectrum shows two resonances for the central n-complexed aromatic at 126.5 and 73.0 ppm, four resonances for the phenoxy substituents a t 155.2, 130.1, 124.9, and 118.4 ppm, and two resonances for the Cp* ligand a t 96.1 and 9.6 ppm. The positive-ion FAB mass spectrum of 5 shows the cation at m l z = 591.
Organometallics, Vol. 14, No. 8, 1995 3743 It is interesting to note that no selectivity in C-C1 nucleophilic substitution is observed in reactions of [Cp*Ru(~6-1,3,5-trichlorobenzene)l+SO~CF3(1) with 1equiv of potassium phenoxide or thiophenoxide in polar solvents at 25 "C. The lH NMR spectrum shows a series of resonances which correspond to an approximately statistical distribution of starting material (11, mono-, di-, and trisubstituted (5) Cp*Ru+ species. This observation of equivalent C-C1 reactivity further supports the outstanding activating ability of the Cp*Ru+ moiety. Similar behavior was observed previously using [Cp*R~(~~-l,4-dichlorobenzene)l+SO&F~as a monomer for nucleophilic substitution polymerization^.^^^^ Reactions at low temperature to encourage selectivity were not studied. At this time, the scope of nucleophiles (aliphatic amines, alkoxides, thioalkoxides, malonates, or cyanide) which can be used with these highly halogenated arene complexes has not been fully explored. However, nucleophiles that react cleanly with the corresponding ~~~~~ mono- and dichloro Cp*Ru+ arene c o m p l e x e ~will likely be successful with these tri- and tetrachloro analogs. Note that nucleophiles that do not react quantitatively may afford a complex mixture of products. Decomplexation of the functionalized arene-Cp*Ru+ complexes was explored by a variety of oxidative, ligand displacement, and photolytic methods and, in general, was challenging and highly inefficient. Specifically, the traditional arene displacement reactions (thermally in DMSO, 160 "C, 2 h, or photochemically in CH3CN, 450 W, 1h) afford only partial decomplexation of complexes 5, 6, 8, and 9 and no detectable decomplexation of complexes 7 and 10-14. These results further accentuate the outstanding n-complexing ability of the Cp*Ru+ moiety, especially to highly electron-rich aromatics such as the tri- and tetrafunctionalized products. Investigation of more rigorous decomplexation methods is planned. Opportunities for Highly Functionalized Aromatics. Cp*Ru+ activated nucleophilic substitution provides a unique route to highly functionalized aromatic small molecules and may offer opportunities for synthesis of soluble, metallomacromolecules with controlled architectures. The tris- and tetrakis-4-aminophenoxysubstituted derivatives 7 and 12 are particularly interesting compounds for branch points or crosslinking agents in polyamide and polyimide syntheses or cores for star polymers. Similarly, the 4-chloro- and 4-fluoro-substituted derivatives 8,9,13, and 14 initiate the concept of a divergent approach to metallodendrimers.l0
Experimental Section General Procedures. All procedures were carried out in a glovebox under a nitrogen atmosphere or in Schlenk-type glassware on a vacuum line. Tetrahydrofuran (THF) was dried and distilled from sodium metal under nitrogen before use. All other solvents, purchased as anhydrous grade from Aldrich, were stored over 3A molecular sieves under nitrogen before use. [C~*RU(CH~CN)~]+SO~CF~was prepared by using the procedures described previously.11bAll potassium aryloxides or thioaryloxides were prepared by reaction of the corresponding phenol or thiophenol with potassium tertbutoxide (1.0 equiv) in THF at 66 "C for 6 h. The THF soluble salts were isolated by removal of the THF solvent in vacuo; the THF insoluble salts were collected by filtration under
3744 Organometallics, Vol. 14,No. 8, 1995
Dembek and Fagan
ion FAB) cation, m l z calcd 591.14, found 591.13. Anal. Calcd nitrogen. All potassium salts were dried in vacuo a t 60 "C for for C35H3306SF3R~:C, 56.83; H, 4.50. Found: C, 56.63; H, 16 h. All reagents (Aldrich) were used as received. 'H (300.0 4.50. MHz) and 13C (75 MHz) NMR spectra were recorded on a QE300 GE spectrometer using DMSO-ds as solvent with [Cp%~(~~-1,3,5-tris(thiophenoxy)benzene)l+SO&F3(6). tetramethylsilane as a n external standard. Positive-ion atom Compound 6 was prepared by the same procedure described fast atom bombardment (FAB) mass spectra were taken with for compound 5 using potassium thiophenoxide as the nucleoa VG ZAB-E double-focusing instrument equipped with a Xephile. Yield: 96%. 'H NMR (DMSO-&): 7.44-7.42 (m, 15 gas ionization gun. Elemental analyses were preformed by H, Ar H), 5.88 (s, 3 H, arene), 1.86 (s, 15 H, CH3) ppm. I3C MicroAnalysis, Inc., Wilmington, DE. NMR(DMSO-ds): 133.2, 130.0, 129.6, 128.9, 103.9,96.7,85.5, 9.0 ppm. MS (positive-ion FAB) cation, m l z calcd 639.08, [Cp'R~(~~-1,3,5-trichlorobenzene)]+SO&F3(1). A 100 found 639.21. Anal. Calcd for C35H3303S4F3Ru: C, 53.35; H, mL Schlenk flask was charged with 1,3,5-trichlorobenzene 4.22. Found: C, 53.54; H, 4.27. (1.64 g, 9.04 mmol, 1.15 equiv) and [Cp*Ru(CH3CN)3IfS0&F3(4.00 g, 7.87 mmol) in THF (70 mL). The reaction was stirred [Cp'Ru(~6-l,3,5-tris(4-aminophenoxy)benzene)l+S0~and heated at 66 "C for 16 h and cooled to room temperature. CF3- (7). A 50 mL Schlenk flask charged with 1 (0.30 g, 0.53 Diethyl ether (ca. 30 mL) was added to the solution to mmol) and potassium 4-aminophenoxide (0.31 g, 2.12 mmol, precipitate a white solid that was collected by filtration, 4 equiv) in CH3CN (25 mL) was stirred a t 60 "C for 2 h. The washed twice with 10 mL portions of diethyl ether, and dried excess potassium 4-aminophenoxide was filtered from the in vacuo. Yield: 72.5%. lH NMR (DMSO-&): 7.21 (s, 3 H, reaction mixture, and the solvent was removed in vacuo. The arene), 1.88 (s, 15 H, CH3) ppm. I3C NMR (DMSO-&): 102.5, residue was dissolved in methylene chloride (25 mL) extracted 98.7, 89.1, 8.5 ppm. MS (positive-ion FAB) cation, m / z calcd with water (2 x 25 mL), and the organic layer was dried over 416.95, found 417.07. Anal. Calcd for C I ~ H I ~ C ~ ~ S O ~ C,F ~ R Umagnesium : sulfate. After filtration, the solvent was removed 36.02; H, 3.20. Found: C, 35.89; H, 3.12. in vacuo and the residue was dissolved in THF (ca. 8 mL) with warming. Slow addition of diethyl ether (ca. 5 mL) precipi[Cp'Ru(~6-l,2,4,5-tetrachlorobenzene)l+SO~CF~(2). tated a white solid that was collected by filtration and dried Compound 2 was prepared by the same procedure described in vacuo a t 80 "C for 4 h to remove coordinated CH3CN solvent. for 1 using 1.3equiv of 1,2,4,5-tetrachlorobenzene.Yield: 78%. Yield: 82%. 'H NMR (DMSO-&): 6.86 (d, J = 8.9 Hz, 6 H, 'H NMR (DMSO-ds): 7.66 (s, 2 H, arene), 1.82 (s, 15 H, CH3) Ar H), 6.56 (d, J = 8.9 Hz, 6 H, Ar H), 5.79 (s, 3 H, arene), ppm. 13C NMR (DMSO-&): 130.2, 99.3, 88.5, 8.0 ppm. MS 1.92 (s, 15 H, CH3) ppm. 13CNMR (DMSO-&): 146.6, 143.9, (positive-ion FAB) cation, m I z calcd 450.9, found 450.9. Anal. 129.0, 120.3, 114.7, 94.9, 68.8, 10.0 ppm. MS (positive-ion Calcd for C17Hl7C14RuSO3F3: C, 33.96; H, 2.85. Found: C, FAB) cation, m l z calcd 636.2, found 636.2. Anal. Calcd for 33.83; H, 2.66. c, 53.57; H, 4.62, N, 5.35. Found: c, C35H36N306SF3R~: [Cp*Ru(q6-pentachlorobenzene)]+SO&F3(3). A 50 mL 53.02; H, 4.41; N, 5.29. Schlenk flask was charged with pentachlorobenzene (3.70 g, [Cp'Ru(q6-1,3,5-tris(4-chlorophenoxy)benzene)] +SOs14.80 mmol, 5 equiv) and [ C ~ * R U + ( C H ~ C N ) ~ ] + S O(1.50 ~CF~CF3- (8). Compound 8 was prepared by the same procedure g, 2.95 mmol) in dioxane (25 mL). The reaction was stirred described for compound 7 using potassium 4-chlorophenoxide and heated at 85 "C for 24 h. The solids that precipitated on as the nucleophile. A modification in the isolation and cooling the reaction mixture to room temperature were colpurification of 8 was that the mixed solvent system of lected by filtration and washed twice with 30 mL portions of methylene chloride/ethanol (80/20) was used for the extractoluene to remove unreacted pentachlorobenzene. The retions, since the product was not completely soluble in methmaining solids were washed twice with 10 mL portions of diethyl ether and dried in vacuo. Yield: 73%. 'H NMR ylene chloride. Yield: 84%. 'H NMR (DMSO-&): 7.53 (d, J = 9.1 Hz, 6 H, Ar HI, 7.30 (d, J = 9.1 Hz, 6 H, Ar H), 6.49 (s, (DMSO-&): 7.81 (s, 1H, arene), 1.77 (s, 15 H, CH3). 13CNMR 3 H, arene), 1.96 (s, 15 H, CH3) ppm. 13C NMR (DMSO-&): (DMSO-ds): 104.3, 103.9, 102.9, 100.1, 89.0, 7.8 ppm. MS 154.4, 129.9, 128.6, 125.8, 119.9, 96.5, 73.9, 9.5 ppm. MS (positive-ion FAB) cation, m l z calcd 484.87, found 484.87. (positive-ion FAB) cation, m / z calcd 693.03, found 693.23. Anal. Calcd for C ~ & & ~ ~ R U S O C, ~ F32.12; ~: H, 2.54. R U : H, 3.56. Anal. Calcd for C ~ ~ H ~ O O & C ~ ~C,F ~49.86; Found: C, 31.85; H, 2.35. Found: C, 49.61; H, 3.27. [Cp*Ru(~6-hexachlorobenzene)l+SO&F3(4). Compound 4 was prepared by the same procedure described for 3 [Cp'Ru(q61,3,5-tris(4-fluorophenoxy)benzene)]~SO3using hexachlorobenzene. Further purification was achieved CF3- (9). Compound 9 was prepared by the same procedure by dissolving the solids in 15 mL of nitromethane and filtering described for compound 7 using potassium 4-fluorophenoxide as the nucleophile. A modification in the isolation and the solution. Slow addition of ca. 5 mL of diethyl ether to the filtrate precipitated tan crystals that were collected by filtrapurification of 9 was that the mixed solvent system of tion, washed twice with 5 mL portions of diethyl ether, and methylene chloridelethanol (80/20) was used for the extractions, since the product was not completely soluble in methdried in vacuo. Yield: 42%. 'H NMR (DMSO-&): 1.65 (s, ylene chloride. Yield: 81%. 'H NMR (DMSO-&): 7.32-7.29 CH3). I3C NMR (DMSO-&): 104.0, 100.8, 7.2 ppm. MS (positive-ion FAB) cation, m / z calcd 518.83, found 518.91. (m, 12 H, Ar H), 6.32 (s, 3 H, arene), 1.96 (s, 15 H, CH3) ppm. 13CNMR (DMs0-d~):158.9 (d, 'JCF= 341 Hz), 151.6, 126.8, Anal. Calcd for C17H~.&16RuS03F3: C, 30.47; H, 2.26. 120.3 (d, 3 J c = ~ 8.6 Hz), 116.9 (d, 2 J c = ~ 23.7 Hz), 96.3, 72.9, Found: C, 30.42; H, 2.14. 9.7 ppm. MS (positive-ion FAB) cation, m / z calcd 645.12, [Cp*Ru(y6-l,3,5-tris(phenoxy)benzene)lfSO~CF3(5). A found 645.44. Anal. Calcd for C3&006SF&u: c, 52.96; H, 50 mL Schlenk flask charged with 1 (0.30 g, 0.53 mmol) and 3.81. Found: C, 52.95; H, 3.49. potassium phenoxide (0.23 g, 1.75 mmol, 3.3 equiv) in CH3CN (25 mL) was stirred at 25 "C for 1h. To ensure complete [Cp*Ru(v61,2,4,5-tetrakis(phenoxy)benzene)l~SO3substitution, the reaction was warmed a t 60 "C for 1 h. The CF3-(10). A 50 mL Schlenk flask charged with 2 (0.25 g, 0.42 solvent was removed in vacuo, the residue was dissolved in mmol) and potassium phenoxide (0.24 g, 1.83 mmol, 4.4 equiv) methylene chloride (15 mL) and extracted with water (2 x 20 in CH3CN (20 mL) was stirred at 25 "C for 3 h and a t 60 "C mL), and the organic layer was dried over magnesium sulfate. for 1 h. The solvent was removed in vacuo, the residue was After filtration, the solvent was removed in vacuo and the dissolved in methylene chloride (20 mL) and extracted with residue was dissolved in acetonitrile (ca. 8 mL). Slow addition water (2 x 25 mL), and the organic layer was dried over of diethyl ether (ca. 10 mL) precipitated a white solid that was magnesium sulfate. After filtration, the solvent was removed collected by filtration and dried in vacuo. Yield: 86%. 'H in vacuo and the residue was dissolved in THF (ca. 7 mL). Addition of diethyl ether (ca. 8 mL) precipitated a white solid NMR (DMSO-&): 7.49-7.20 (m, 15 H, Ar H), 6.27 (s, 3 H, arene), 1.98 (s, 15 H, CH3) ppm. 13CNMR (DMSO-&): 155.2, that was collected by filtration and dried in vacuo a t 60 "C for 130.1, 126.5, 124.9, 118.4, 96.1, 73.0, 9.6 ppm. MS (positive2 h. Yield: 72%. lH NMR (DMSO-&): 7.40-7.09 (m, 20 H,
Organometallics, Vol. 14, No. 8, 1995 3745
Synthesis and Substitution of ($-Cp*Ru) nComplexes
similar procedure described for compound 12 using potassium 4-chlorophenoxide. A modification in the isolation and puri(DMSO-ds): 156.0, 129.7, 124.2, 117.6, 117.0, 96.8, 76.2, 9.1 fication of 13 was that the mixed solvent system of methylene ppm. MS (positive-ion FAB) cation, m / z calcd 683.17, found chloride/ethanol(80/20) was used for the extractions, since the 683.34. Anal. Calcd for C ~ I H ~ ~ R U S O C,~59.20; F ~ : H, 4.48. product was not completely soluble in methylene chloride. Found: C, 59.35; H, 4.54. Isolation of 13 was achieved by addition of diethyl ether to a [Cp'Ru(~6-1,2,4,5-tetrakis(thiophenoxy)benzene~l~solution of the product in CHsCN/THF solvents to afford white S03CF3-(11). Compound 11 was prepared by a similar solids. Yield: 71%. IH NMR (DMSO-&): 7.44 (d, J = 9.1 Hz, procedure described for compound 10 using potassium thiophe8 H, Ar H), 7.31 (d, J = 9.1 Hz, 8 H, Ar H), 7.00 (s,2 H, arene), noxide. Yield: 83.1%. 'H NMR (DMSO-&): 7.44-7.38 (m, 1.97 (s, 15 H, CH3) ppm. 13CNMR (DMSO-&): 154.9, 129.6, 20 H, Ar H), 5.60 (s, 2 H, arene), 1.83 (s, 15 H, CH3) ppm. 13C 128.2,118.7,117.5,97.3,76.6,9.1 ppm. MS(positive4onFAB) NMR(DMSO-&): 132.6, 130.1, 129.6, 128.9, 102.8,96.8,87.9, cation, m / z calcd 819.02; found 819.22. Anal. Calcd for 8.8 ppm. MS (positive-ion FAB) cation, m l z calcd 747.08, C41H3307SC14F3R~:C, 50.79; H, 3.43. Found: C, 50.23; H, ~ F ~ H, : found 747.06. Anal. Calcd for C ~ I H ~ ~ R U S ~C,O54.95; 3.36. 4.16. Found: C, 54.91; H, 4.17. [Cp'Ru(~s-1,2,4,5-tetrakis(4-fluorophenoxy)ben[Cp'Ru(y6-1,2,4,5-tetrakis(4-aminophenoxy)benzene)l+SO&Fs- (14). Compound 14 was prepared by a zene)]+SO&F3- (12).A 50 mL Schlenk flask charged with similar procedure described for compound 12 using potassium 2 (0.35 g, 0.58 mmol) and potassium 4-aminophenoxide (0.43 4-fluorophenoxide. A modification in the isolation and purig, 2.91 mmol, 5 equiv) in CH3CN (15 mL) was stirred at 60 "C fication of 14 was that the mixed solvent system of methylene for 4 h. The excess potassium 4-aminophenoxide was filtered chloride/ethanol(80/20)was used for the extractions, since the and washed with 5 mL of CH3CN and the CH3CN was removed product was not completely soluble in methylene chloride. in vacuo. The purple-colored residue was dissolved in methIsolation of 14 was achieved by addition of diethyl ether to a ylene chloride (25 mL) and extracted with water (2 x 30 mL), solution of the product in CH&N/THF solvents to afford white and the organic layer was dried over magnesium sulfate. After solids. Yield: 79%. 'H NMR (DMSO-&): 7.32-7.19 (m, 16 filtration, the methylene chloride was removed in vacuo and H, Ar H), 6.79 (s, 2 H, arene), 1.98 (s, 15 H, CH3) ppm. 13C the tan-colored residue was dissolved in THF (ca. 12 mL) with NMR (DMSO-&): 158.5 (d, 'JCF= 240 Hz), 152.5, 118.6 (d, warming. Slow addition of diethyl ether (ca. 6 mL) precipi3Jc~= 8.5 Hz), 117.9, 116.5 (d, 2 J ~ 23.6 ~ =Hz), 97.1, 76.3, 9.3 tated a white solid that was collected by filtration and dried ppm. MS (positive-ion FAB) cation, m / z calcd 755.14, found in vacuo at 90 "C for 4 h to remove coordinated CH3CN solvent. ~ R U :H, 3.68. 755.30. Anal. Calcd for C ~ ~ H ~ ~ O ~ SC:F 54.49; Yield: 68%. 'H NMR (DMSO-d6): 6.88 (d, J = 8.9 Hz, 8 H, Found: C, 54.03; H, 3.60. Ar H), 6.53 (d, J = 8.9 Hz, 8 H, Ar H), 5.94 (s, 2 H, arene), 1.91 (s, 15 H, CH3) ppm. 13CNMR (DMSO-&): 145.8, 145.7, 118.9, 118.0, 114.6, 95.4, 73.0, 9.5. MS (positive-ion FAB) Acknowledgment. We thank Dr. J. Lazar for FAB cation, m / z calcd 743.22, found 743.41. Anal. Calcd for m a s s spectral data, Dr. R. Burch and Dr. A. Feiring for C41H4107SN4F3R~:C, 55.21; H, 4.63; N, 6.28. Found: C, insightful discussions, and J. M. Barker and R. Davis 55.43; H, 4.78; N, 6.14 ppm. for technical assistance.
Ar H), 6.67 (s, 2 H, arene), 1.99 (s, 15 H, CH3) ppm. 13CNMR
[Cp'Ru(vO-1,2,4,5-tetrakis(4-chlorophenoxy)benzene)]+SO&Fs- (13). Compound 13 was prepared by a
OM950198+
