Synthesis and Characterization of Novel Dinuclear Copper (I

Ruben Alfredo Toscano,† and Cecilio Alvarez-Toledano†,*. Instituto de Quı´mica, UniVersidad Nacional Auto´noma de Me´xico, Circuito Exterior, ...
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Inorg. Chem. 2006, 45, 1766−1773

Synthesis and Characterization of Novel Dinuclear Copper(I) Complexes. Dimerization of [CuL(PPh3)2] (L ) methyl 3-hydroxy-3-(p-R-phenyl)-2-propenedithioate) Ivan Garcı´a-Orozco,†,*,§ Ma. Carmen Ortega-Alfaro,‡ Jose´ G. Lo´pez-Corte´s,† Ruben Alfredo Toscano,† and Cecilio Alvarez-Toledano†,* Instituto de Quı´mica, UniVersidad Nacional Auto´ noma de Me´ xico, Circuito Exterior, Ciudad UniVersitaria, Coyoaca´ n, C. P. 04510 Mexico, DF, and Departamento de Quı´mica Orga´ nica, Facultad de Quı´mica, UniVersidad Nacional Auto´ noma de Me´ xico, Circuito Exterior, Ciudad UniVersitaria, Coyoaca´ n, CP 04510 Mexico, DF Received September 16, 2005

We report the synthesis of new copper(I) complexes 6a−e from methyl 3-hydroxy-3-(p-R-phenyl)-2-propenedithioate ligands. These complexes were characterized by IR and 1H, 13C, and 31P NMR spectroscopy. The expected O,Scoordination mode was confirmed by the X-ray diffraction studies of 6b and 6e. The unexpected dimerization of 6b−e leads to the formation of four novel dinuclear copper(I) compounds (7b−e). The dinuclear complex structure was fully established by the X-ray diffraction analysis of 7a, in which the presence of a Cu−Cu interaction was observed.

Introduction The organosulfur compounds are useful ligands, and their metal complexes have been applied as catalysts in a variety of reactions such as hydrosilylation, oxygen activation, ethylene oligomerization, enantioselective Diels Alder, and asymmetric epoxidation, among others.1 Although the 3-hydroxy-3-(p-R-phenyl)-2-propendithioic acids (1) have been known since 1888,2 they have rarely been used as ligands.3 Two coordination modes have been proposed for these compounds,3a,4 taking into account the structural arrangement of donor atoms (Chart 1): (a) an S,S-coordination mode, * To whom correspondence should be addressed. E-mail: ivagarci@ cimat.cl or [email protected]. Fax: 52 55 5616 2217. † Instituto de Quı´mica. § Present address: Centro para la Investigacio ´ n Interdisciplinaria Avanzada en Ciencias de los Materiales (CIMAT), Universidad de Chile, Blanco Encalada 2008, piso zocalo, Santiago, Chile. ‡ Departamento de Quı´mica Orga ´ nica. (1) Among others: (a) Evans, D. A.; Michael, F. E.; Tedrow, J. S.; Campos, K. R. J. Am. Chem. Soc. 2003, 125, 3534. (b) Mandimutsira, B. S.; Yamarik, J. L.; Brunold, T. C.; Gu, W.; Cramer, S. P.; Riordan, C. G. J. Am. Chem. Soc. 2001, 123, 9194. (c) McGuinness, D. S.; Wasserscheid, P.; Keim, W.; Morgan, D.; Dixon, J. T.; Bollmann, A.; Maumela, H.; Hess, F.; Englert, U. J. Am. Chem. Soc. 2003, 125, 5272. (d) Smith, J. N.; Shirin, Z.; Carrano, C. J. J. Am. Chem. Soc. 2003, 125, 868. (e) Mancheno, O. G.; Arrayas, R. G.; Carretero, J. C. Organometallics 2005, 24, 557. (f) Xia, Q.-H.; Ge, H.-Q.; Ye, C.-P.; Liu, Z.-M.; Su, K.-X. Chem. ReV. 2005, 105, 1603. (2) (a) Meyer, V. Ber. 1888, 21, 353. (b) Kelver, C. Ber. 1910, 43, 1252. (c) Kelver, C.; Schwars, A. Ber. 1911, 44, 1698. (d) Kelver, C.; Schwars, A. Ber. 1912, 45, 137.

1766 Inorganic Chemistry, Vol. 45, No. 4, 2006

Chart 1. Proposed Coordination Fashion of Compound 1

forming a four-membered chelated ring (2) and (b) an O,Scoordination mode, forming a six-membered chelated ring (3); only the former has been observed. Recently, we have shown that the S,S-coordination mode is preferred over the O,S-mode in 3-hydroxy-3-(p-R-phenyl)2-propendithioic acids 1, and this behavior could be explained by electronic correlation analysis.5 Furthermore, these copper(I) coordination compounds (4) display a tautomeric equilibrium in solution (Chart 2). (3) (a) Weignad, W.; Bosl, K.; Polborn, K. Chem. Ber. 1990, 123, 1339. (b) Weigand, W.; Saumweber, R.; Schulz, P. Z. Naturforsch. 1993, 48b, 1080. (c) Buchweitz, J.; Gompper, R.; Polborn, K.; Robl, C.; Sailer, M.-T.; Weigand, W. Chem. Ber. 1994, 127, 23. (d) AlvarezToledano, C.; Enrı´quez, J.; Alfredo Toscano, R.; Martı´nez-Garcı´a, M.; Corte´s-Corte´s, E.; Osornio, Y. M.; Garcı´a-Mellado, O.; Gutie´rrezPe´rez, R. J. Organomet. Chem. 1999, 38, 577. (e) Alvarez-Toledano, C.; Delgado, E.; Donnadieu, B.; Herna´ndez, E.; Martı´n, G.; Zamora, F. Inorg. Chim. Acta 2003, 351, 119. (4) (a) Coucouvanis, D.; Fackler, J. P., Jr. J. Am. Chem. Soc. 1967, 89, 1346. (b) Caffery, M. L.; Coucouvanis, D. J. Inorg. Nucl. Chem. 1975, 37, 2081. (c) Liu, C.-Y.; Lih, J.-J. Fresenius’ J. Anal. Chem. 1988, 332, 171. (5) Garcı´a-Orozco, I.; Lo´pez-Corte´s, J. G.; Alfredo Toscano, R.; Penieres Carrillo, G.; Alvarez-Toledano, C. Inorg. Chem. 2004, 43, 8572.

10.1021/ic0515958 CCC: $33.50

© 2006 American Chemical Society Published on Web 01/17/2006

NoWel Dinuclear Copper(I) Complexes Chart 2. Tautomeric Equilibrium of Copper(I) Complexes from Ligands 1

Chart 3. Observed Coordination Mode of Compound 5

To study the less favored O,S-coordination of dithio acids 1, we could possibly use dithioester derivatives6 (5), taking advantage of the minor coordination capability of the -SMe rather than the -SH group.7 These compounds have received more attention as ligands8 than dithio acids 1, because of their stability and the monothio-β-diketone similarity (Chart 3). Nickel (II),8c copper(II),8a,d cobalt(III), and zinc(II)8d complexes of dithioester derivatives have been obtained that show electron delocalization over the six-membered chelated ring.8d Furthermore, manganese(II), iron(II), cobalt(II and III), nickel(II), palladium(II), platinum(II), copper(II), and zinc(II) complexes of these ligands with large chain substituents were synthesized for possible use as metallomesogenes.8e In all cases, the dithioester derivatives display an O,Scoordination mode, forming a six-membered chelated ring. With the aim of continuing our studies about the reactivity of type 1 ligands toward transition metals, we studied the copper(I) O,S-coordination mode in the corresponding dithioester compound 5. In this paper, we report the synthesis and structural characterization of new copper(I) complexes of 3-hydroxy-3-(p-R-phenyl)-2-propendithioic methyl esters and their unexpected dimerization to obtain novel dinuclear copper(I) complexes. Experimental Section Materials. Infrared spectra were recorded on either a PerkinElmer 283B or 1420 spectrophotometer, and data are expressed in wavenumbers (cm-1). All NMR spectra were recorded on a JEOL Eclipse +300 using CDCl3 as the solvent, and the chemical shifts were referenced to TMS in 1H and 13C and 30% H3PO4 in 31P. The MS-FAB spectra were obtained on a JEOL JMS SX 102A. Elemental analyses were performed by the USAI, Facultad de Quı´mica UNAM. Melting points were obtained on a Melt-Temp II apparatus and are uncorrected. All commercial reagents were of ACS grade and used without further purification. THF was distilled from benzophenone under nitrogen atmosphere. The 3-hydroxy(6) (a) Larsson, F. C. V.; Lawesson, S.-O. Tetrahedron 1972, 28, 5341. (b) Dieter, R. K. Tetrahedron 1986, 42, 3029. (7) Murray, S. G.; Hartley, F. Chem. ReV. 1981, 81, 365. (8) (a) Gompper, R.; Schaefer, H. Chem. Ber. 1967, 100, 591. (b) Dorange, G.; Schaefer, H. Chem. Ber. 1967, 100, 591. (c) Dorange, G.; Kergoat, R.; Guerchais, J. E. Bull. Soc. Chim. Fr. 1969, 3835. (d) Dorange, G.; Guerchais, J. E. Bull. Soc. Chim. Fr. 1971, 43. (e) Saumweber, R.; Robl, C.; Weignad, W. Inorg. Chim. Acta 1998, 269, 83.

3(p-R-phenyl)propendithioic acids 1 were synthesized according to Larsson’s method.6a Bis(triphenylphosphine)copper(I) nitrate was obtained by previous literature preparation.9 General Procedure. Synthesis of Methyl 3-Hydroxy-3-(pmethoxyphenyl)-2-propenedithioate (5a). To a solution of 3-hydroxy-3-(p-metoxyphenyl)-2-propendithioic acid (1.11 g, 4.8 mmol) in 15 mL of THF were added calcium hydride (0.10 g, 2.4 mmol) and methyl iodide (0.3 mL, 4.8 mmol) at room temperature. The mixture was stirred for 2 h and then extracted with water and ethyl acetate. The organic layer was dried with anhydrous Na2SO4, and the solvent was removed in vacuo. The product was purified by silica gel (70-230 mesh) chromatography using hexane as the eluant to obtain a crystalline yellow solid. Yield: 0.10 g (8%). Mp: 76-77 °C. IR (KBr, cm-1): 3430.5 w, 1603.1 m, 1582.0 s, 1545.9 m, 1503.9 s, 1430.2 m, 1232.3 s, 1180.9 m, 1052.8 m, 959.6 m, 838.2 m, 782.2 m, 585.1 m, 454.6 m. MS-EI+ (m/z %): 240 (M+, 51), 193 ([M - MeS]+, 100), 135 ([MeOC6H4CO]+, 86.2), 107 ([MeOC6H4]+, 6.88). 1H NMR (CDCl3): δ 2.65 (s, 3H, H-8), 3.87 (s, 3H, MeO), 6.95 (d, 2H, J ) 8.70 Hz, H-6), 6.95 (s, 1H, H-2), 7.86 (d, 2H, J ) 8.70 Hz, H-5), 15.19 (s, 1H, H-9). 13C NMR (CDCl3): δ 17.0 (C-8), 55.6 (MeO), 107.2 (C-2), 114.3 (C-6), 126.3 (C-4), 128.7 (C-5), 162.9 (C-7), 169.6 (C-3), 215.7 (C-1). Synthesis of Methyl 3-Hydroxy-3-(p-methylphenyl)-2-propenedithioate (5b). Yield: 0.84 g (79%). Mp: 58-60 °C. IR (KBr, cm-1): 3382.6 w, 1654 w, 1584.0 s, 1560.3 s, 1529.8 m, 1502.9 s, 1456.8 m, 1421.3 m, 1236.9 s, 1184.9 m, 1051.5 m, 943.2 m, 833.4 m, 771.4 m, 673.1 m, 567.9 m, 547.6. MS-EI+ (m/z %): 224 (M+, 63), 177 ([M - MeS]+, 100), 119 ([MeC6H4CO]+, 62), 91 ([MeC6H4]+, 42). 1H NMR (CDCl3): δ 2.41 (s, 3H, Me), 2.67 (s, 3H, H-8), 6.97 (s, 1H, H-2), 7.25 (d, 2H, J ) 8.49 Hz, H-6), 7.79 (d, 2H, J ) 8.49 Hz), 15.13 (s, 1H, H-9). 13C NMR (CDCl3): δ 17.1 (C-8), 21.7 (Me), 107.6 (C-2), 126.8 (C-6), 129.6 (C-5), 131.4 (C-4), 142.8 (C-7), 169.7 (C-3), 216.7 (C-1). Synthesis of Methyl 3-Hydroxy-3-phenyl-2-propenedithioate (5c). Yield: 0.65 g (52%). Mp: 55-57 °C. IR (KBr, cm-1): 3731.9 w, 1585.7 m, 1559.0 s, 1489.3 m, 1451.6 m, 1392.1 m, 1298.5 w, 1236.3 s, 1055.7 m, 961.2 m, 938.9 s, 823.0 m, 754.2 s, 682.9 m, 605.5 m, 547.9 m. MS-EI+ (m/z %): 210 (M+, 53), 163 ([M MeS]+, 100), 105 ([C6H5CO]+, 61), 77 ([C6H5]+, 41). 1H NMR (CDCl3): δ 2.65 (s, 3H, H-8), 6.96 (s, 1H, H-2), 7.46 (m, 1H, H-7), 7.47 (m, 2H, H-6), 7.88 (m, 2H, H-5), 15.09 (s, 1H, H-9). 13C NMR (CDCl3): δ 17.2 (C-8), 107.9 (C-2), 126.8 (C-6), 128.8 (C-5), 131.9 (C-7), 134.3 (C-4), 169.3 (C-3), 217.4 (C-1). Synthesis of Methyl 3-Hydroxy-3-(p-fluorophenyl)-2-propenedithioate (5d). Yield: 0.76 g (71%). Mp: 94-96 °C. IR (KBr, cm-1): 3432.0 w, 1600.4 s, 1575.0 s, 1501.3 s, 1426.5 m, 1226.1 s, 1162.6 m, 1053.6 m, 963.1 m, 844.7 m, 763.3 m, 573.0 m, 545.9 m, 467.0 m. MS-EI+ (m/z %): 228 (M+, 61), 181 ([M - MeS]+, 100), 123 ([FC6H4CO]+, 61), 95 ([FC6H4]+, 27). 1H NMR (CDCl3): δ 2.66 (s, 3H, H-8), 6.90 (s, 2H, H-2), 7.14 (m, 2H, H-6), 7.90 (m, 2H, H-5), 15.11 (s, 1H, H-9). 13C NMR (CDCl3): δ 17.2 (C-8), 107.6 (C-2), 116.0 (d, 2JC-F ) 21.9 Hz, C-6), 129.0 (d, 3JC-F ) 8.6 Hz, C-5), 130.5 (C-4), 165.0 (d, 1JC-F ) 253.8 Hz, C-7), 168.1 (C-3), 217.9 (C-1). Synthesis of Methyl 3-Hydroxy-3-(p-chlorophenyl)-2-propenedithioate (5e). Yield: 0.33 g (31%). Mp: 76-77 °C. IR (KBr, cm-1): 3429.4 w, 2922.1 w, 1591.0 s, 1555.5 m, 1485.2 m, 1415.6 m, 1229.9 m, 1092.0 m, 1054.0 m, 101.6 m, 962.5 m, 832.2 m, 778.5 m, 551.9 w, 439.2 w. MS-EI+ (m/z %): 244 (M+, 52), 197 (9) (a) Cotton, F. A.; Goodgame, D. M. L. J. Chem. Soc. 1960, 5267. (b) Jardine, F. H.; Vohra, A. G.; Young, F. J. J. Inorg. Nucl. Chem. 1971, 33, 2941.

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Garcı´a-Orozco et al. ([M 100), 139 63), 111 26). 1H NMR (CDCl ): δ 2.66 (s, 3H, H-8), 6.91 (s, 1H, H-2), 7.42 (d, 3 2H, J ) 8.95 Hz, H-6), 7.82 (d, 2H, J ) 8.95 Hz, H-5), 15.06 (s, 1H, H-9). 13C NMR (CDCl3): δ 17.3 (C-8), 107.7 (C-2), 128.0 (C-6), 129.1 (C-5), 132.8 (C-4), 138.1 (C-7), 167.8 (C-3), 217.7 (C-1). General Procedure for the Synthesis of Bis(triphenylphosphine-P)[methyl-3-hydroxy-3-(p-methoxy-phenyl)-2-propenedithioate-O,S]copper(I) (6a). To an aqueous solution of methyl3-hydroxy-3(p-methoxy-phenyl)-propendithioate 5a (0.10 g, 0.42 mmol) was added 2 mL of a 0.10 g/mL solution of NaOH (0.42 mmol) in ethanol and a solution of Cu(PPh3)2NO3 (0.28 g, 0.42 mmol) in CH2Cl2. The orange solution turned dark red. The mixture was stirred for 15 min; the organic layer was then separated and dried with anhydrous Na2SO4. The solvent was distilled off under vacuum until there was a minimal amount of CH2Cl2; ethanol was then added to precipitate the complex, which was filtered and dried in a vacuum to give an orange solid. Yield: 0.21 g (60%). Mp: 148-150 °C. IR (KBr, cm-1): 3430.0 w, 3050.9 w, 1602.1 m, 1582.9 m, 1537.4 m, 1442.5 vs, 1404.8 s, 1298.5 m, 1239.6 s, 1170.4 m, 1094.3 m, 1029.2 m, 934.9 m, 779.0 m, 744.3 m, 696.4 s, 509.8 m. FAB-MS+ (m/z %): 891 ([M + Cu]+, 30). 1H NMR (CDCl3): δ 2.53 (s, 3H, H-8), 3.82 (s, 3H, MeO), 6.94 (s, 1H, H-2), 6.82 (d, 2H, J ) 8.81 Hz, H-6), 7.71 (d, 2H, J ) 8.81 Hz, H-5), 7.30 (m, 30H, PPh3). 13C NMR (CDCl3): δ 17.0 (C-8), 55.4 (MeO), 110.2 (C-2), 113.3 (C-6), 128.5 (d, 3JPC ) 8.6 Hz, C-m, PPh3), 129.3 (C-5 + C-p, PPh3), 133.9 (d, 2JPC ) 15.5 Hz, C-o, PPh3), 134.4 (d, 1JPC ) 21.2 Hz, C-ipso, PPh3), 134.8 (C-4), 161.6 (C-1), 181.4 (C-3), 188.2 (C-1). 31P NMR (CDCl3): δ-2.07 (broad signal). Anal. Calcd for C47H41CuO2P2S2: C, 68.22; H, 4.99. Found: C, 69.29; H, 4.86. Synthesis of Bis(triphenylphosphine-P)[methyl-3-hydroxy3-(p-methyl-phenyl)-2-propenedithioate-O,S]copper(I) (6b). Yield: 0.29 g (85%). Mp: 152-154 °C. IR (KBr, cm-1): 3382.6 w, 3050.9 w, 1581.9 m, 1532.8 m, 1441.4 s, 1398.8 m, 1316.9 m, 1292.0 m, 1241.9 m, 1181.9 m, 1094.0 m, 936.9 m, 777.2 m, 744.5 m, 695.7 s, 509.7 m. FAB-MS+ (m/z %): 875 ([M + Cu]+, 52). 1H NMR (CDCl ): δ 2.36 (s, 3H, Me), 2.56 (s, 3H, H-8), 7.03 (s, 3 1H, H-2), 7.15 (d, 2H, J ) 8.13 Hz, H-6), 7.68 (d, 2H, J ) 8.13 Hz, H-5), 7.30 (m, 30H, PPh3). 13C NMR (CDCl3): δ 17.0 (C-8), 21.6 (Me), 110.5 (C-2), 127.5 (C-6), 128.5 (d, 3JPC ) 8.6 Hz, C-m, PPh3), 128.8 (C-5), 129.4 (C-p, PPh3), 133.9 (d, 2JPC ) 16.6 Hz, C-o, PPh3), 134.5 (d, 1JPC ) 18.9 Hz, C-ipso, PPh3), 139.3 (C-4), 140.8 (C-1), 182.2 (C-3), 189.3 (C-1). 31P NMR (CDCl3): δ -1.35 (broad signal). Anal. Calcd for C47H41CuOP2S2: C, 69.57; H, 5.09. Found: C, 70.16; H, 4.98. Synthesis of Bis(triphenylphosphine-P)[methyl-3-hydroxy-3phenyl-2-propenedithioate-O,S]copper(I) (6c). Yield: 0.17 g (43%). Mp: 172-175 °C. IR (KBr, cm-1): 3427.2 w, 3052.0 w, 1585.8 w, 1534.6 m, 1456.6 s, 1428.7 s, 1314.8 m, 1290.9 m, 1238.7 m, 1094.5 m, 937.5 m, 806.6 m, 744.8 s, 695.0 s, 621.9 m, 508.6 s. FAB-MS+ (m/z %): 869 ([M + Cu]+, 21) 1H NMR (CDCl3): δ 2.53 (s, 3H, H-8), 6.93 (s, 1H, H-2), 7.64 (m, 2H, H-5), 7.30 (m, 33H, PPh3 + H-7 + H-6). 13C NMR (CDCl3): δ 17.0 (C-8), 110.5 (C-2), 127.3 (C-6), 128.4 (d, 3JPC ) 8.7 Hz, C-m, PPh3), 128.9 (C-5), 129.4 (C-p, PPh3), 133.9 (d, 2JPC ) 15.6 Hz, C-o, PPh3), 134.6 (d, 1JPC ) 19.6 Hz, C-ipso, PPh3), 130.2 (C-4), 142.0 (C-1), 182.1 (C-3), 190.1 (C-1). 31P NMR (CDCl3): δ -2.22 (broad signal). Anal. Calcd for C46H39CuOP2S2: C, 69.28; H, 4.93. Found: C, 72.09; H, 4.90. Synthesis of Bis(triphenylphosphine-P)[methyl-3-hydroxy-3(p-fluoro-phenyl)-2-propenedithioate-O,S]copper(I) (6d). Yield: 0.24 g (62%). Mp: 163-164 °C. IR (KBr, cm-1): 3430.8 MeS]+,

([ClC6H4CO]+,

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([ClC6H4]+,

w, 3051.9 w, 1598.0 m, 1530.0 m, 1477.3 m, 1443.8 s, 1397.0 m, 1309.7 m, 1230.3 m, 1154.1 m, 1093.9 m, 937.7 m, 847.9 m, 786.8 m, 744.7 m, 695.4 s, 597.7 m, 506.8 m. FAB-MS+ )m/z %): 891 ([M + Cu]+, 30). 1H NMR (CDCl3): δ 2.52 (s, 3H, H-8), 6.85 (s, 1H, H-2), 6.95 (m, 2H, H-6), 7.64 (m, 2H, H-5), 7.30 (m, 30H, PPh3). 13C NMR (CDCl3): δ 16.9 (C-8), 110.4 (C-2), 115.1 (d, 2J 3 FC ) 21.2 Hz, C-6), 128.4 (d, JPC ) 6.9 Hz, C-m, PPh3), 129.4 (d, 3JFC ) 13.7, C-5), 129.3 (C-p, PPh3), 133.9 (d, 2JPC ) 16.0 Hz, C-o, PPh3), 134.2 (d, 1JPC ) 32.9 Hz, C-ipso, PPh3), 138.5 (C-4), 164.4 (C-1), 180.6 (C-3), 191.0 (C-1). 31P NMR (CDCl3): δ -2.26 (broad signal). Anal. Calcd for C46H38CuFOP2S2: C, 67.76; H, 4.70. Found: C, 67.53; H, 4.54. Synthesis of Bis(triphenylphosphine-P)[methyl-3-hydroxy3-(p-chloro-phenyl)-2-propenedithioate-O,S]copper(I) (6e). Yield: 0.26 g (75%). Mp: 143-144 °C. IR (KBr, cm-1): 3443.0 w, 3376.9 w, 3051.7 w, 1581.5 m, 1528.0 m, 1442.3 s, 1312.5 m, 1285.8 m, 1092.1 m, 938.5 m, 744.0 m, 696.3 m, 509.4 m. FABMS+ (m/z %): 891 ([M + Cu]+, 30) 1H NMR (CDCl3): δ 2.56 (s, 3H, H-8), 6.97 (s, 1H, H-2), 7.30 (d, 2H, J ) 8.53 Hz, H-6), 7.67 (d, 2H, J ) 8.53 Hz, H-5), 7.30 (m, 30H, PPh3). 13C NMR (CDCl3): δ 16.9 (C-8), 110.1 (C-2), 128.5 (C-6), 128.4 (d, 3JPC ) 9.2 Hz, C-m, PPh3), 128.7 (C-5), 129.4 (C-p, PPh3), 134.0 (d, 2JPC ) 16.1 Hz, C-o, PPh3), 134.3 (d, 1JPC ) 20.6 Hz, C-ipso, PPh3), 136.2 (C-4), 140.8 (C-7), 180.4 (C-3), 190.4 (C-1). 31P NMR (CDCl3): δ -2.06 (broad signal). Anal. Calcd for C46H38CuClOP2S2: C, 66.42; H, 4.60. Found: C, 69.03; H, 4.53. General Procedure for the Synthesis of Bis{µ2-[methyl-3-(pmethylphenyl)-3-hydroxy-2-propenedithioate-O,S]}bis(triphenylphosphine-P)dicopper(I) (7b). An ethanol suspension of bis(triphenylphosphine-P)[methyl-3-hydroxy-3-(p-methyl-phenyl)-2-propenedithioate-O,S]copper(I) (6b) (0.10 g, 0.12 mmol) was refluxed for 1 h. The dark red solid was filtrated and washed with ethyl acetate to obtain a crystalline product. Yield: 0.06 g (90%). Mp: 183-184 °C. IR (KBr, cm-1): 3050 w, 1605 w, 1577 m, 1538 s, 1454 s, 1400 m, 1319 m, 1244 m, 1180 m, 1094 m, 935 m, 796 m, 774 m, 743 m, 694 s, 520 m, 499 m. FAB-MS+ (m/z %): 1159 ([M + Cu]+, 13). 1H NMR (CDCl3): δ 2.39 (s, 3H, Me), 2.62 (s, 3H, H-8), 7.23 (d, 2H, J ) 8.26 Hz, H-6), 7.24 (s, 1H, H-2), 7.42 (m, 9H, PPh3), 7.58 (m, 6H, PPh3), 7.85 (d, 2H, J ) 8.26 Hz, H-5). 13C NMR (CDCl3): δ 16.8 (C-8), 21.6 (Me), 110.8 (C-2), 127.7 (C-6), 128.9 (d, 3JPC ) 9.2 Hz, C-m, PPh3), 129.1 (C-5), 130.3 (C-p, PPh3), 132.4 (d, 1JPC ) 36.7 Hz, C-i, PPh3), 134.0 (d, 2JPC ) 13.8 Hz, C-o, PPh3), 139.1 (C-4), 141.4 (C-7), 182.2 (C-3), 190.0 (C-1). 31P NMR (CDCl3): δ 5.19 (broad signal). Synthesis of Bis{µ2-[methyl-3-phenyl-3-hydroxy-2-propenedithioate-O,S]}bis(triphenylphosphine-P)dicopper(I) (7c) Yield: 0.04 g (55%). Mp: 182-183 °C. IR (KBr, cm-1): 3051 w, 1584 w, 1535 s, 1458 s, 1429 s, 1319 s, 1237 m, 1094 m, 934 m, 796 m, 774 m, 694 m, 622 m, 513 m. FAB-MS+ (m/z %): 1131 ([M + Cu]+, 10). 1H NMR (CDCl3) δ 2.61 (s, 3H, H-8), 7.24 (s, 1H, H-2), 7.42 (m, 11H, H-7 + H-6 + PPh3), 7.58 (m, 7H, PPh3), 7.92 (m, 2H, H-5). 13C NMR (CDCl3) δ 16.9 (C-8), 110.9 (C-2), 127.6 (C-6), 128.4 (C-5), 128.9 (d, 3JPC ) 10.4 Hz, C-m, PPh3), 130.3 (C-p, PPh3), 132.4 (d, 1JPC ) 38.1 Hz, C-i, PPh3), 134.0 (d, 2JPC ) 16.2 Hz, C-o, PPh3), 130.9 (C-7), 141.9 (C-4), 182.2 (C-3), 190.4 (C-1). 31P NMR (CDCl3): δ 5.13 (broad signal). Synthesis of Bis{µ2-[methyl-3-(p-fluorophenyl)-3-hydroxy-2propenedithioate-O,S]}bis(triphenylphosphine-P)dicopper(I) (7d) Yield: 0.05 g (72%). Mp: 186-187 °C. IR (KBr, cm-1): 3050 w, 1596 s, 1540 s, 1451 s, 1397 m, 1314 m, 1230 s, 1154 m, 1095 m, 936 m, 851 m, 780 s, 694 s, 495 m. FAB-MS+ (m/z %): 1167 ([M + Cu]+, 7). 1H NMR (CDCl3): δ 2.62 (s, 3H, H-8), 7.08 (m, 2H, H-6), 7.19 (s, 1H, H-2), 7.42 (m, 9H, PPh3), 7.75 (m, 6H, PPh3),

NoWel Dinuclear Copper(I) Complexes Table 1. X-ray Crystallographic Data for Compounds 5b, 6b, 6e, and 7b

formula fw cryst syst space group Z a (Å) b (Å) c (Å) R (deg) β (deg) γ (deg) V (Å3) dcalcd (g/cm3) T (K) wavelength (Å) abs coeff (mm-1) GOF on F2 Ra (%) [I > 2σ(I)] Rwb (%)

5b

6b

6e

7b

C11 H12 O S2 224.33 triclinic P1h 2 5.1192(5) 8.0297(8) 14.459(1) 82.664(2) 87.786(2) 74.965(2) 569.29(9) 1.309 293 0.71073 0.432 1.017 5.22 13.67

C47 H41 Cu O P2 S2 811.40 monoclinic P21/n 4 10.506(2) 12.334(2) 31.934(5) 90.00 93.63(1) 90.00 4129.4(12) 1.305 293 0.71073 0.742 1.013 7.16 11.35

C46 H38 Cl Cu O P2 S2 831.81 monoclinic P21/n 4 10.4843(4) 12.306(1) 31.777(1) 90.00 93.063(1) 90.00 4094.1(3) 1.350 293 0.71073 0.814 1.030 7.23 11.74

C58 H52 Cu2 O2 P2 S4 1098.26 monoclinic P21/c 2 12.678(3) 18.570(5) 11.059(4) 90.00 98.54(2) 90.00 2575.0(13) 1.416 293 0.71073 1.093 0.983 8.18 15.85

7.93 (m, 2H, H-5). 13C NMR (CDCl3): δ 16.8 (C-8), 110.6 (C-2), 115.3 (d, 2JFC ) 22.9 Hz, C-6), 129.9 (d, 3JPC ) 9.2 Hz, C-m, PPh3), 128.9 (d, 3JFC ) 22.9 Hz, C-5), 130.4 (C-p, PPh3), 132.3 (d, 1J 2 PC ) 34.4 Hz, C-i, PPh3), 133.9 (d, JPC ) 16.0 Hz, C-o, PPh3), 137.9 (C-4), 166.2 (C-7), 180.2 (C-3), 190.9 (C-1). 31P NMR (CDCl3): δ 5.38 (broad signal). Synthesis of Bis{µ2-[methyl-3-(p-chlorophenyl)-3-hydroxy-2propenedithioate-O,S]}bis(triphenylphosphine-P)dicopper(I) (7e) Yield: 0.05 g (78%). Mp: 188-189 °C. IR (KBr, cm-1): 3050 w, 1580 m, 1537 m, 1450 s, 1311 m, 1240 m, 1091 m, 936 m, 793 m, 738 m, 695 m, 522 m. FAB-MS+ (m/z %): 1201 ([M + Cu]+, 5). 1H NMR (CDCl3): δ 2.62 (s, 3H, H-8), 7.18 (s, 1H, H-2), 7.36 (d, 2H, J ) 6.61 Hz, H-6), 7.42 (m, 9H, PPh3), 7.56 (m, 6H, PPh3), 7.85 (m, 2H, J ) 6.61 Hz, H-5). 13C NMR (CDCl3): δ 16.8 (C-8), 110.5 (C-2), 128.5 (C-6), 128.9 (d, 3JPC ) 11.5 Hz, C-m, PPh3), 129.0 (C-5), 130.4 (C-p, PPh3), 132.4 (d, 1JPC ) 36.9 Hz, C-i, PPh3), 134.0 (d, 2JPC ) 16.2 Hz, C-o, PPh3), 136.9 (C-7), 140.3 (C-4), 180.5 (C-3), 191.8 (C-1). 31P NMR (CDCl3): δ 5.23 (broad signal). X-ray Crystallography Structure Determination. Yellow single crystal of compound 5b, red single crystals of compounds 6b and 6e, and dark red single-crystal compound 7b were mounted on a glass fiber at room temperature. The crystals were then placed on Siemens P4/PC (6b and 7b) and Bruker Smart Apex (5b and 6e) diffractometers equipped with Mo KR radiation; decay was negligible in both cases. Details of the crystallographic data collected on compounds 5b, 6b, 6e, and 7b are provided in Table 1. Systematic absences and intensity statistics were used in space group determination. All structures were solved using direct methods. Anisotropic structure refinements were achieved using full-matrix least-squares techniques on all non-hydrogen atoms. All hydrogen atoms (except H-1 of compound 5b) were placed in idealized positions on the basis of hybridization, with isotropic thermal parameters fixed at 1.2 times the value of the attached atom. Structure solutions and refinements were performed using SHELXTL version 6.10.10

Results and Discussion Ligands 5a-e: Methyl 3-Hydroxy-3-(p-R-phenyl)-2propenedithioate. The synthesis of methyl 3-hydroxy-3-(pR-phenyl)-2-propenedithioate (R ) MeO, Me, H, F, Cl) 5a-e from corresponding dithio acids was carried out by a (10) SHELXTL, version 6.10; Bruker Analytical X-ray Systems: Madison, WI, 2000.

Table 2. Selected Bond Distances (Å) and Bond Angles (°) of Compound 5b bond

distance

bond

angle

O1-C3 C2-C3 C1-C2 C1-S1 C1-S2

1.326(3) 1.358(4) 1.413(4) 1.664(3) 1.742(3)

C1-C2-C3 S1-C1-C2 S1-C1-S2 O1-C3-C2

127.1(3) 126.2(2) 122.20(17) 123.0(3)

modified literature method.6a Dithioester ligands were identified by IR, MS-IE+ and 1H NMR and they are in accordance with literature. The low yield of compound 5a is due to a double methyl substitution of the dithio acid, which gives as a main product the corresponding ketene dithioacetal.6,11 The 13C NMR data for these compounds have not been described before. The spectra of compounds 5a-e display a signal at δ 17.1, which was assigned to the SMe group. The vinyl carbon atom signal (C2) was observed at δ 107. All aromatic carbon signals appear in the region of δ 125145. The signal at δ 169.0 ca. was assigned to the C-3 carbon atom; this signal is shifted downfield (∆δ ≈ 3.0) from the dithio acids because of a major electron density over this center. A signal around δ 217.0 was assigned to the C-1 dithioester carbon atom.12 This signal is shifted upfield (∆δ ≈ 7.0) from the dithio acid compounds, which means a slight decrease in electron density over this center, which correlates well with the weak CdS vibration in IR and the incremental change in electron density of H-9 in 1H NMR. Crystal Structure of Compound 5b. The structure of ligand 5b was fully established by X-ray diffraction analysis of a monocrystal obtained from a slow evaporation from hexane solution. The ORTEP view of compound 5b is shown in Figure 1. Selected bond distances and bond angles are summarized in Table 2. Compound 5b is in enol form, showing an intramolecular hydrogen bond of O-H‚‚‚S type. The O-H, S‚‚‚H, and O‚‚‚S bond distances and the O-H‚‚‚S bond angle (Table 3), among the 1H NMR chemical shift of H-9, allow us to (11) Ortega-Alfaro, M. C.; Lo´pez-Corte´s, J. G.; Toscano, R. A.; AlvarezToledano, C. J. Braz. Chem. Soc. 2005, 16, 362-371. (12) Kanodia, S.; Coucouvanis, D. Inorg. Chem. 1982, 21, 469.

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Garcı´a-Orozco et al.

Figure 1. X-ray crystal structure of ligand 5b. Ellipsoids are shown at the 30% probability level. Table 3. Hydrogen Bonds for Compound 5b (Å and deg) D-H‚‚‚A

d(D-H)

d(H‚‚‚A)

d(D‚‚‚A)