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1、Inorg. Chem. 2002, 41, 65216526 Cyclometalated Ruthenium Chloro and Nitrosyl Complexes HassanHadadzadeh, Maria C. DeRosa, Glenn P. A. Yap, Ali R. Rezvani,| and Robert J. Crutchley*, Chemistry Department, Shahid Beheshti UniVersity, P.O. Box 19395, Tehran, Iran, Ottawa-Carleton Chemistry Institute, C

2、arleton UniVersity, 1125 Colonel By DriVe, Ottawa, Ontario, Canada K1S 5B6, and UniVersity of Ottawa, Ottawa, Ontario, Canada, K1N 6N5 Received February 4, 2002 The novel cyclometalated Ru(III) complex, Ru(2-phpy)(trpy)ClPF6toluene1, and the Ru-NO6 complex, Ru- (2-phpy)(trpy)NOPF62 2, where trpy is

3、2,2: 6,2-terpyridine and phpyis 2-phenylpyridine, havebeenprepared andcharacterizedby elemental analysis, IR, 1H NMR, andelectronic absorption spectroscopies, cyclic voltammetry, and crystallography. The crystal structure of 1 showed the chloride ion trans to the -bonding phenyl group of phpy and is

4、 an unusual example of a stable paramagnetic cyclometalated complex. The crystal structure of 2 shows the nitrosyl ligand trans to the -bonding phenyl group of phpy. The significant distortion of the normally linear RuNObondangle (167.1(4) canbe largely ascribedto the strong -donor properties of the

5、 phenyl group. Introduction Our research into mixed-valence complexes1 has led us to cyclometalated complexes because of a desire to reduce the charge of the complex cation and dramatically perturb the stability of metal orbitals. One of the most commonly used ligands, which can form cyclometalated

6、complexes, is 2-phenylpyridine (phpyH). Under suitable conditions, this potential application to solar energy and sensor devices.2 In the course of preparing cyclometalated precursor complexes to our mixed-valence systems, it became apparent that the chemistry of these cyclometalated complexes was s

7、ufficiently unique to warrant further investigation. Cyclometalated complexes of ruthenium are usually six coordinate with ruthenium in the 2+ oxidation state, and 3 ligand will deprotonate and will bind to a metal ion as a they therefore obey the 18-electron rule. Indeed, a literature bidentate ani

8、on ligand (phpy-), Cyclometalated complexes have gained great interest because of their photophysical and photochemical properties and their * Author to whom correspondence should be addressed. E-mail: rcrutch ccs.carleton.ca. Shahid Beheshti University. Carleton University. niversity of Ottawa. Sis

9、tan & Baluchestan University. (1) (a) Evans, C. E. B.; Naklicki, M. L.; Rezvani, A. R.; White, C. A.; Kondratiev, V. V.; Crutchley, R. J. J. Am. Chem. Soc. 1998, 120, 13096-13103. (b) Mosher, P. J.; Yap, G. P. A.; Crutchley, R. J. Inorg. Chem. 2001, 40, 1189-1195. search of ruthenium cyclometalated

10、complexes revealed only (2) (a) Bruce, D.; Richter, M. M. Anal. Chem. 2002, 74, 1340-1342. (b) Adachi, C.; Baldo, M. A.; Forrest, S. R.; Thompson, M. E. Appl. Phys. Lett. 2000, 77, 904-906. (c) Lee, C.-L.; Lee, K. B.; Kim, J.-J. Appl. Phys. Lett. 2000, 77, 2280-2082. (d) Colombo, M. G.; Brunhold, T.

11、 C.; Riedener, T.; Gudel, H. U.; Fortsch, M.; Burgi, H.-B. Inorg. Chem. 1994, 33, 545-550. (e) Dedeian, K.; Djurovich, P. I.; Garces, F. O.; Carlson, G.; Watts, R. J. Inorg. Chem. 1991, 30, 1685-1687. (f) Craig, C. A.; Watts, R. J. Inorg. Chem. 1989, 28, 309-313. (g) Garces, F. O.; King, K. A.; Watt

12、s, R. J. Inorg. Chem. 1988, 27, 3464-3471. (3) (a) Brissard, M.; Gruselle, M.; Malezieux, B.; Thouvenot, R.; Guyard- Duhayon, C.; Convert, O. Eur. J. Inorg. Chem. 2001, 1745-1751. (b) Barigelletti, F.; Ventura, B.; Collin, J. P.; Kayhanian, R.; Garvina, P.; Sauvage, J. P. Eur. J. Inorg. Chem. 2000,

13、113-119. (c) Bennett, M. A.; Clark, A. M.; Contel, M.; Rickard, C. E. F.; Roper, W. R.; Wright, L. J. J. Organomet. Chem. 2000, 601, 299-304. (d) Clark, A. M.; Rickard, C. E. F.; Roper, W. R.; Wright, L. J. Organometallics 1999, 18, 2813-2820. (e) Guari, Y.; Sabo-Etienne, S.; Chaudret, B. J. Am. Che

14、m. Soc. 1998, 120, 4228-4229. (f) Coudret, C.; Fraysse, S.; Launay, J.-P. Chem. Commun. 1998, 663-664. (g) Mul, W. P.; Elsevier: C. J.; Vuurman, M. A.; Smeets, W. J. J.; Spek, A. L.; De Boer, J. L. J. Organomet. Chem. 1997, 532, 89-100. (h) Collin, J.- P.; Kayhanian, R.; Sauvage, J.-P.; Calogero, G.

15、; Barigelletti, F.; De Cian, A.; Fischer, J. Chem. Commun. 1997, 775-776. (i) Aneetha, H.; Rao, C. R. K.; Rao, K. M.; Zacharias, P. S.; Feng, X.; Mak, T. C. W.; Srinivas, B.; Chiang, M. Y. J. Chem Soc., Dalton Trans. 1997, 1697-1704. 10.1021/ic020451f CCC: $22.00 2002 American Chemical Society Inorg

16、anic Chemistry, Vol. 41, No. 24, 2002 6521 Publishedon Web 11/07/2002 Hadadzadeh et al. 6522 Inorganic Chemistry, Vol. 41, No. 24, 2002 one example of a cyclometalated mononuclear Ru(III) complex4 and family of dinuclear complexes,5 both incor- porating the tridentate dianion ligand, and its derivat

17、ives. For both studies,4,5 the assigned oxidation state of ruthenium was supported by EPR spectroscopy and elemental analysis. In this study, we report the facile synthesis of a paramagnetic Ru(III) cyclometalated complex, Ru(2-phpy)(trpy)ClPF6toluene 1, where trpy is 2,2: 6,2-terpyridine, and the c

18、haracterization of 1 by crystal- lography, elemental analysis, IR and UV-vis spectroscopies, and cyclic voltammetry. Nitrosyl complexes have gained a deserved recognition as important models for nitrogen oxide regulation in biology.6 Recent reviews7 of the coordination chemistry of the nitrosyl liga

19、nd speak to the importance of this research, and so it was decided to attempt the synthesis of a nitrosyl complex using 1. The result, Ru(2-phpy)(trpy)NOPF62 2, was prepared in nonaqueous solution and in high yields. Complex 2 was characterized by crystallography, elemental analysis, IR, 1H NMR and

20、UV-vis spectroscopies, and cyclic volta- mmetry. Spectroelectrochemical studies of 1 and 2 were also performed. Experimental Section Equipment. UV-vis spectroscopy was performed on a CARY 5 UV-vis-NIR spectrophotometer. IR spectra were taken with a BOMEM Michelson-100 FT-IR spectrophotometer (KBr di

21、sks). 1H NMR data from acetonitrile-d3 solutions were obtained by using a Bruker AMX-400 spectrometer. Cyclic voltammetry was performed using a BAS CV-27 voltammograph and plotted on a BAS XY recorder. The sample cell consisted of a double-walled glass crucible with an inner volume of 15 mL which wa

22、s fitted with a Teflon lid incorporating a three-electrode system and argon bubbler. The cell temperature was maintained at (25.0 ( 0.1) C by means of a HAAKE D8 recirculating bath. BAS 2013 Pt electrodes (1.6 mm diameter) were used as the working and counter electrodes. A silver wire functioned as

23、a pseudo-reference electrode. Acetonitrile (MeCN) was dried over P2O5 and vacuum distilled. Tetrabutylam- monium hexafluorophosphate (TBAH), purchased from Aldrich, was twice recrystallized from 1:1 ethanol/water and vacuum-dried at 110 C. Ferrocene (E) 0.665 V versus NHE) was used as an internal re

24、ference.8 An OTTLE cell was used to perform the spectroelectrochemistry.9 The cell had interior dimensions of (4) Hariram, R.; Santra, B. K.; Lahiri, G. K. J. Organomet. Chem. 1997, 540, 155-163. (5) Munshi, P.; Samanta, R.; Lahiri, G. K. J. Organomet. Chem. 1999, 586, 176-183. (6) Wang, P. G.; Xian

25、, M.; Tang, X.; Wu, X.; Wen, Z.; Cai, T.; Janczuk, A. J. Chem. ReV. 2002, 102, 1091-1134. (7) (a) Hayton, T. W.; Legzdins, P.; Sharp, W. B. Chem. ReV. 2002, 102, 935-991. (b) Ford, P. C.; Lorkovic, I. M. Chem. ReV. 2002, 102, 993-1017. (8) Gennett, T.; Milner, D. F.; Weaver, M. J. J. Phys. Chem. 198

26、5, 89, 2787-2794. (9) (a) Krejcik, M.; Danek, M.; Hartl, F. J. Electroanal. Chem. 1991, 317, 179-187. (b) Evans, C. E. B. Ph.D. Thesis, Carleton University, 1997. roughly 1 2 cm with a path length of 0.2 mm, was fitted with a silver/silver chloride reference electrode, and used ITO (indium- tin oxid

27、e) coated glass for the working and counter electrodes. Elemental analyses were performed by Canadian Microanalytical Services. Materials. All reagents and solvents used were reagent grade or better. Nitrosonium tetrafluoroborate was purchased from Aldrich, and Ru(trpy)Cl3 was synthesized according

28、to literature procedures.10 ITO glass plates were purchased from Delta- Technologies. Preparation of Ru(2-phpy)(trpy)ClPF6toluene, 1. Ru- (trpy)Cl3 (0.441 g, 1 mmol) and 2-phenylpyridine (0.155 g, 1 mmol) were dissolved in 20 mL of DMF and refluxed for 4 h, after which TlPF6 (0.70 g, 2 mmol) was add

29、ed and the solution refluxed for a further 1 h. The solution was cooled to -20 C overnight and then filtered through Celite to remove the fine white TlCl precipitate. Diethyl ether (600 mL) was then added to the filtrate, precipitating the crude product, which was filtered off and then was purified

30、by chromatography (grade III alumina, weakly acidic, 40 3 cm column). Elution with 1:2 acetonitrile/toluene yielded a purple band, which was not identified, followed by the green band of the target complex. The latter band was collected, evaporated to dryness, and then recrystallized by slow evapora

31、tion of a 3:1 acetonitrile/toluene solution of the complex. Yield: 0.39 g (51%). Anal. Calcd for Ru(2-phpy)(trpy)ClPF6toluene (C33H27N4F6PClRu): C, 52.08; H, 3.58; N, 7.36. Found: C, 51.88; H, 3.67; N, 7.53. Preparation of Ru(2- phpy)(trpy)NOPF62, 2. A mixture of 1 (0.669 g, 1 mmol) and TlPF6 (0.349

32、 g, 1 mmol) was placed in 100 mL of acetonitrile and stirred at reflux for 1 h. The solution was chilled to -20 C and filtered through Celite to remove the white TlCl precipitate. To the filtrate was then added nitrosonium tetrafluoroborate (0.14 g,1.2 mmol), and the resulting solution was stirred w

33、ith slight heating (34-45 C) for 5 h. The solution was evaporated, and the crude light brown solid recrystallized by the diffusion of diethyl ether into an acetonitrile solution of the complex. Yield: 0.65 g, (80%). Anal. Calcd for Ru(2-phpy)(trpy)NOPF62 (C26H19N5OF12P2Ru): C, 38.63; H, 2.37; N, 8.6

34、6. Found: C, 38.90; H, 2.45; N, 8.82. IR (NO): 1858 cm-1. 1H NMR (400 MHz): 9.06 (1H, doublet), 8.75 (3H, multiplet), 8.60 (2H, doublet), 8.33 (4H, multiplet), 7.98 (3H, multiplet), 7.79 (1H, triplet), 7.57 (2H, triplet), 7.17 (1H, triplet), 6.88 (1H, triplet), 5.79 (1H, doublet) ppm. Crystallograph

35、y. Crystals of 1 were grown by the slow evaporation of a 3:1 acetonitrile/toluene solution of the complex. Diffusing diethyl ether into an acetonitrile solution of the complex grew crystals of 2. For both complexes, the data were collected on a 1K Siemens Smart CCD using Mo KR radiation ( ) 0.71073

36、) at 203(2) K using an -scan technique and corrected for absorptions using equivalent reflections.11 No symmetry higher than triclinic was observed, and solution in the centric space group option yielded chemically reasonable and computationally stable results of refinement. The structure was solved

37、 by direct methods and refined with full-matrix least-squares procedures. For 1, two half- occupied molecules of toluene were found cocrystallized near the inversion center in the asymmetric unit. These were refined with phenyl groups idealized as rigid, flat hexagons. In addition, the PF6 counterio

38、n in 1 was restrained to have similar cis FF interatomic separations. Anisotropic refinement was performed on all non-hydrogen atoms. All hydrogen atoms were calculated. (10) Sullivan, B. P.; Calvert, J. M.; Meyer, T. J. Inorg. Chem. 1980, 19, 1404-1407. (11) Blessing, R. Acta Crystallogr. 1995, A51

39、, 33-38. Cyclometalated Ruthenium Chloro and Nitrosyl Complexes Inorganic Chemistry, Vol. 41, No. 24, 2002 6523 . 6 2 2 Table 1. Crystal Data and Structure Refinement for Complexes 1 and 2 1 2 formula fw C33H27F6ClN4PRu 761.08 C26H19F12N5OP2Ru 808.47 space group P1h P1h cryst syst Ztriclinic 2 tricl

40、inic Dc, g/cm3 1.636 1.864 a, 11.165(3) 8.9387(8) b, 11.335(3) 10.4325(9) c, 13.447(4) 16.7004(15) R, deg 68.768(2) 77.6950(10) ?, deg 78.303(3) 88.7732(2) , deg 80.274(3) 71.3870(10) V, 3 1544.7(8) 1440.2(2) temp, K 203(2) 203(2) GOF on F2 1.038 1.063 R1a 0.0518 0.0509 wR2b 0.1075 0.1494 a R1 ) |Fo

41、| - |Fc|/|Fo|. b wR2 ) (w(|Fo| - |Fc|)2/w|Fo|2)1/2 Scattering factors are contained in the SHELXTL 5.1 program library. Results and Discussion The synthetic strategy to prepare complex 1 was based on a modification of the procedure used to prepare Ru(bpy)2- (2-phpy)+.12 The latter complex was prepar

42、ed by the reaction of stoichiometric amounts of Ru(bpy)2Cl2, phe- nylpyridine, and silver(I) tetrafluoroborate in refluxing dichloromethane, without the addition of base to deprotonate 2-phenylpyridine. In this study, a similar reaction between the Ru(III) complex, Ru(trpy)Cl3, 2-phenylpyridine, and

43、 thallium hexafluorophosphate in refluxing dimethylforma- mide (eq 1), gave 1 in 51% final yield. Refluxing dimeth- Ru(trpy)Cl3 + 2TlPF6 + Hphpy f Ru(phpy)(trpy)Cl+ + 2TlClV + 2PF - + H+ (1) ylformamide was thought necessary to overcome the greater inertness of Ru(III) toward substitution reactions.

44、 Elemental analysis of 1 was entirely consistent with its proposed stoichiometry, and attempts to determine its 1H NMR spectrum showed that the complex was paramagnetic, supporting a Ru(III) oxidation state. An unambiguous determination of the stoichiometry of 1 was made by crystallography. For 1, c

45、rystal structure data can be found in Table 1 and an ORTEP is shown in Figure 1 together with selected bond lengths and bond angles. The crystal structure shows terpyridine, phenylpyridine, and chloride ligands coordinated Figure 1. ORTEP drawing of Ru(2-phpy)(trpy)ClPF6toluene 1. The counterion and

46、 solvent of crystallization have been omitted for clarity. Selected bond lengths () and bond angles (deg): Ru-N(3), 1.971(4); Ru- N(4), 2.060(4); Ru-N(2), 2.076(3); Ru-C(11), 2.024(4); Ru-N(1), 2.091- (4); Ru-Cl, 2.4431(13); N(3)-Ru-C(11), 95.43(16); N(3)-Ru-N(4), 79.70(15); C(11)-Ru-N(4), 90.93(15)

47、; N(3)-Ru-N(2), 79.05(14); C(11)- Ru-N(2), 86.23(15); N(4)-Ru-N(2), 158.19(15); N(3)-Ru-N(1), 174.54- (14); C(11)-Ru-N(1), 79.77(16); N(4)-Ru-N(1); 97.68(14); N(2)-Ru- N(1), 103.07(14); N(3)-Ru-Cl, 90.64(10); C(11)-Ru-Cl, 171.43(13); N(4)-Ru-Cl, 96.11(10); N(2)-Ru-Cl, 89.00(10); N(1)-Ru-Cl, 94.41- (

48、10). Cyclic voltammetry was performed on an acetonitrile solution of 1 with 0.1 M TBAH supporting electrolyte. Three couples were observed at +0.46, -1.32, and -1.61 V vs NHE that we assigned to the Ru(III/II) reduction couple and two terpyridine reduction couples, respectively. Terpyridines * orbit

49、als are expected to be more stable compared to anionic phenylpyridine and should be reduced first.1b The cyclic voltammogram of the Ru(III/II) couple possessed equivalent anodic and cathodic waves whose separation (60 mV) was independent of scan rate (100-450 mV/s). Figure 2 shows the spectroelectrochemistry associated with this Ru- (III/II) couple. In Figure 2, complex 1 shows low-energy bands in the visible region that, due to the