Studies on Catalytically Active Ruthenium Carbonyl Bipyridine

shiR reactions and in COz-reduction processes. cis-(CO),cis(Cl)-[Ru(bpy)(CO)~Clzl. (la),. Cll~ (3), and [Ru(bpy)(CO)&lH] (4) have been synthesized fro...
1 downloads 0 Views 1MB Size
Download PDF
Organometallics 1995, 14,825-833

825

Studies on Catalytically Active Ruthenium Carbonyl Bipyridine Systems. Synthesis and Structural Characterization of [Ru(bpy)(C0)&121, [Ru(bpy)(C0)&1(C(O)OCHdI, [Ru(bpy)(cO)~C112,and [Ru(bpy)(C0)2ClH] (bpy = 2,2'-Bipyridine) Matti Haukka, Jari Kiviaho,t Markku Ahlgrh, and Tapani A. Pakkanen" Department of Chemistry, University of Joensuu, P.O. Box 111, FIN-80101 Joensuu, Finland Received May 12, 1994@ The molecular structures a n d reactivity of several ruthenium mono(bipyridine) carbonyl compounds have been studied as possible model compounds for intermediates in water-gas shiR reactions and in COz-reduction processes. cis-(CO),cis(Cl)-[Ru(bpy)(CO)~Clzl (la), ~i~(CO),tr~n~(Cl)-[R~(bpy)(CO)zClzl (Ib),[Ru(bpy)(C0)2Cl(C(O)OCH3)1(2), [Ru(bpy)(CO)sC l l ~(3),a n d [Ru(bpy)(CO)&lH] (4) have been synthesized from [Ru(C0)&1212 a n d 2,2'bipyridine in T H F or alcohol solutions. The structures of these complexes have been confirmed by single-crystal X-ray crystallography: la,orthorhombic, space group Pbca, a = 12.709(4) A, b = 11.532(5) c = 18.852(5) 2 = 8; lb,triclinic, space group Pi, a = 6.536(4) b = 12.557(7) A, c = 12.595(9) a = 119.81(4)", p = 93.94(6)", y = 98.11(4)", 2 = 4; 2, monoclinic, space group P21/m, a = 7.751(4) b = 11.863(7) A, c = 9.081(6) p = 107.18(4)", 2 = 2; 3,monoclinic, space group C2/m, a = 12.681(5) A, b = 10.165(3) A, c = 10.633(4) p = 114.01(3)", 2 = 2; 4, triclinic, space group Pi, a = 6.407(3) A, b = 8.135(5) c = 12.707(8) a = 89.39(5)", p = 81.56(5)", y = 81.53(4)", 2 = 2. [Ru(bpy)(CO)2Cl(C(0)OCH3)] can be converted directly to [Ru(bpy)(C0)2C1]2under HdCO pressure. It is also possible to convert [Ru(bpy)(CO)zCl]zto [Ru(bpy)(C0)2Cl(C(O)OCH3)1in methanol under HdCO pressure a n d to [Ru(bpy)(CO)&l2] in concentrated HCl solution. [Ru(bpy)(CO)zClHI converts to [Ru(bpy)(CO)&l12 a n d may be a n intermediate in t h e preparation of [Ru(bpy)(C0)2C112. [Ru(bpy)(CO)sCl12can be seen as a model for t h e catalytically active [Ru(bpy)(CO)2], polymer in CO2 reduction. [Ru(bpy)(CO)zClHIa n d [Ru(bpy)(C0)2Cl(C(O)OCH3)1a r e possible models for proposed -Ru(bpy)H and -Ru(bpy)(C(O)OH) intermediates in WGSR. Reversible conversions between [Ru(bpy)(C0)2Cl(C(O)OCH3)1a n d [Ru(bpy)(CO)aCllnoffer also a possible model route for t h e catalytic preparation of methyl formate.

A,

A,

A,

A,

A,

A,

A,

A,

Introduction Ruthenium poly(bipyridines) have been widely studied because of their activity in the water-gas shift In reaction (WGSR)1-4and in the reduction of these processes the catalytic cycles and the structures of probable intermediates are relatively well-documented. Corresponding reactions with ruthenium carbonyl mono(bipyridines)up until now have been studied less frequently. [Ru(bpy)(CO)2C121,a mono(bipyridine) complex, is known as an excellent catalyst for the photochemical and electrochemical reduction of C02 into formate and carbon mon~xide/formate.~Both [RUB(CO)ld2,2'-bipyridinel and [Ru3(C0)12/2,2'-bipyridine/ ~

* E-mail:

A,

~~

tapQoyl.joensuu.fi. + Present address: Technical Research Center of Finland, VTT, Chemical Technology, P.O. Box 1401,FIN-02044VTT, Finland. Abstract published in Advance ACS Abstracts, December 15,1994. (1)Richmond, M. G. J . Organomet. Chem. 1993,457,121. (2)Kelly, J. M.;Vos, J. G. Angew. Chem., Znt. Ed.Engl. 1982,21, 628. (3)Haasnoot, J. G.;Hinrichs, W.; Weir, 0.; Vos, J . Znorg. Chem. 1986,25,4140. (4)Ishida, H.; Tanaka, K.; Morimoto, M.; Tanaka, T. Organometallics 1986,5,724. (5)(a) Tanaka, H.; Nagao, H.; Tanaka, K. Znorg. Chem. 1992,31, 1971.(b) Tanaka, H.; Tzeng, B.-C.; Nagao, H.; Peng, S.-H.; Tanaka, K. Organometallics 1992, 11, 3172. (c) Tanaka, H.; Tzeng, B.- C.; Nagao, H.; Peng, S.-H.; Tanaka, K. Znorg. Chem. 1993,32,1508. (6) Vlcek, A,, Jr. Chemtracts: Znorg. Chem. 1993,5, 1.

Si021 systems have been found to be active in 1-hexene hydroformylation.8 The cluster precursor system [RuQ(C0)12/2,2'-bipyridine/SiOzl is also highly active in WGSR.g The detailed structure of the active form of [Ru~(C0)12/2,2'-bipyridine]is not yet known, but it is probably a mono(bipyridine1 compound. In addition to ruthenium carbonyl bipyridines, a related [RU~(CO)IPI catalyst with a NEt3C1 promoter has proved to be active in the carbonylation of methanol to methyl formate.1° Knowledge of the structures and chemical behavior of ruthenium mono(bipyridine)complexes would be useful in understanding the catalytic properties of related systems. In the present work we introduce the synthesis, reactions, and crystal structures of [Ru(bpy)(CO)nClIz, [ R U ( ~ ~ ~ ) ( C O ) ~ C ~ ( C ( O ) O[Ru(bpy)(CO)2C1HI7 CHB)~, and [Ru(bpy)(CO)zCl21complexes (bpy = 2,2'-bipyridine),

@

(7)(a)Lehn, J.-M.; Ziesel, R. J . Organomet. Chem. 1990,382,157. (b) Ishida, M.; Fujiki, K.; Omba, T.; Ohkubo, K.; Tanaka, K.; Terarda, T.; Tanaka, T. J . Chem. Soc., Dalton Trans. 1990,2155.(c) CollombDunnand-Sauthier, M.-N.; Deronzier, A.; Ziessel, R. J. Chem. Soc., Chem. Commun. 1994, 189. (d) Collomb-Dunand-Sauthier,M.-N.; Deronzier, A.; Ziessel, R. Znorg. Chem. 1994,33, 2961. (8) Alvila, L.;Pakkanen, T. A,; Krause, 0. J . Mol. Cutul. 1993,84, 145 and references therein. (9)Kiiski, U.;Venalainen, T.; Pakkanen, T. A.; Krause, 0. J. Mol. Cutal. 1991,64,163 and references therein. (10)Choi, S. J.;Lee, J. S.; Kim, Y. G. J . Mol. Cutul. 1993,85,L109.

0276-733319512314-Q825$Q9.QQfQ 0 1995 American Chemical Society

826 Organometallics, Vol. 14, No. 2, 1995

Haukka et al.

Scheme 1. Preparation and Reactions of [Ru(bpy)(CO)2C121t [Ru(bpy)(C0)2Cl(C(O)OCHs)l, [R~(bpy)(CO)aClla,and [Ru(bpy)(CO)&lW [R u(C O)3Clz]2t 2,2’-bipyridine

ethanol, isopropanol, 1.heplanol

1

(4)

co .................................. [ R u(bp y)( C 0 )2 C l2 ] 4 (1)

fl

d)

H CI e)

[Ru(bPY)(CO)zCllz (3)

MeOHlCO 4

CO,Hz

9)

b

[ R u(bpy ) ( C 0 )z C I (C(0)O C H3 11 (2 l

Legend: (a) refluxedkeated at 100 “C for 0.5-1 h; (b) heated at 90-100 “C for 1.5-2 h; (c) refluxed for 0.5 h; (d) solvent ethylene glycol, pco = 50 bar, T = 150 “C, t = 17 h; (e) refluxed in HCl(37S); (f) pco = 50 bar, T = 150 “C, t = 17 h; (g) solvent ethylene glycol, p~~ = 25 bar, pco = 25 bar, T = 150 “C, t = 17 h. a

ing bands, a “high frequency“ compound a t 2055-2070 and 1997-2007 cm-’ and a “low frequency” compound a t 2040 and 1980 cm-l. The former have been assigned to the cis(CO),trum(Cl)isomer of [ R ~ ( b p y ) ( C O ) z C l z l ~ ~ - ~ ~ R e s u l t s and Discussion and the latter to the cis(CO),cis(Cl)isomer.14 Ishida et al. have studied the WGSR process catalyzed We have synthesized [Ru(bpy)(COl~Cl2l fkom [Ru(CO)3by [Ru(bpy)2(CO)ClI+ and [ R ~ ( b p y M C 0 ) 2 1 ~ +They .~ C1212 in THF (Scheme la) by successive precipitations proposed that the reaction cycle includes [Ru(bpy)~(CO)(see Experimental Section). Typically, only a pale (H20)I2+, [Ru(bpy)2(CO)(C(O)OH)l+, and [Ru(bpy)zyellow product was formed, but occasionally a pink color (CO)Hl+ intermediates. [Ru(bpy)2(CO)HIf has been was also observed, especially in the first precipitate. isolated and characterized by single-crystal X-ray crysHowever, there were only two strong v(C0) peaks a t t a l l ~ g r a p h y .The ~ crystal structure of [Ru(bpy)n(CO)about 2067 and 2003 cm-l, which indicate the typical (C(O)OH)l+ is not known, but a suitable model com“high frequency” component. The ‘H NMR spectrum pound, [Ru(bpy)z(CO)(C(O)OCH3)]+, has been reported.5b,c of [Ru(bpy)(CO)zCl21proved to be informative. In the [Ru(bpy)z(CO)(C(O)OH)I+ is also a n important intermespectrum of the first precipitate (la)four triplets and diate in C02 reduction. Like the ruthenium bis(bipythree doublets were found in the aromatic region. The ridine) compounds above, [Ru(bpy)(CO)2Clzlis found to triplets and two of the doublets had comparable intensibe active in the reduction of C02.7 Ziessel et al. have ties, but one doublet (8.2 ppm) had almost a double proposed a mechanism for electrocatalytic reduction of intensity. It probably arises from two overlapping C02, which includes a highly air-sensitive, blue polydoublets. In addition to main-peak sets, a n “extra” meric [Ru(bpy)(CO)zl, catalyst and [Ru(bpy)(CO)(C(O)doublet and a triplet were found at 9.2 and 7.7 ppm. OH)] intermediate.7c,d Similar blue, air-sensitive cataTwo other extra signals at about 8.0-8.3 ppm (doublet lysts active in WGSR and 1-hexene hydroformylation and triplet) were partially covered by the main-peak have also been prepared from [RudCO)121 and 2,2’sets. The intensity of this extra peak set varied b i p y ~ i d i n e .However, ~~~ suitable model compounds for independently in different samples, and it became the intermediates in C02 reduction or WGSR catalyzed dominant in the second precipitate (lb). The lH NMR by mono(bipyridine1 compounds are not yet readily spectrum of la can be assigned to the cis(CO),cis(Cl) available. We have studied the preparation, reactions, isomer by assuming that the halves of the bpy ring are and structures of the possible model compounds [Runot equivalent. Dissimilarity can be expected, because (bpy)(CO)zClal,[ R ~ ( ~ ~ Y ) ( C ~ ) ~ C ~ ( C ( O[Ru(bpy)) O C H ~ ) I , in this isomer different ligands (CO and C1) occupy the (C0)2C112, and [Ru(bpy)(CO)2ClH]. The compounds, positions trans to bpy nitrogens. The multiple aromatic their syntheses, and reactions are summarized in peak pattern found in the l3C(lH} NMR spectrum Scheme 1. supports the lH NMR observations. It has been proposed that in the preparation of [Ru(bpy)(CO)zC12]from Preparation and Crystal Structure of [Ru(bpy)(CO)&12]. Preparation and IR studies on [Ru(bpy)(CO)2a “ruthenium red carbonyl solution” a mixture of cis,Clzl have been reported by several a ~ t h 0 r s . l l - l ~ [Rucis and cis,truns isomers are not formed, but a pure (bpy)(CO)&lz] is typically prepared from RuCl3 via yellow [Ru(bpy)(CO)2Clz]and a red-purple mixture of [Ru(CO)~C~Z(THF)I or via “the red carbonyl solution”. [Ru(bpy)(CO)2Clzland [R~(bpy)(CO)C131.~~ Formation of a very small amount of [Ru(bpy)(CO)Clalmay explain Depending on the preparation method, one or two the reddish color occasionally found in our products also. products have been found in these syntheses by IR measurements. Both compounds have two v(C0) stretchHowever, if a larger amount of the monocarbonyl compound is present, it should be observed by IR and (11)Bruce, M.I.; Stone, F. G. A. J. Chem. SOC.A 1967,1238. lH NMR spectroscopy and elemental analysis. In the (12)Kingston, J. V.;Jamieson, J . W. S.;Wilkinson, G. J.Inorg. Nucl. lH NMR and l3C(lH} NMR spectra of the second Chem. 1967,29,133. precipitate (lb)only one aromatic peak set was found (13)Black, D. St. C.; Deacon, G. B.; Thomas, N. C. Aust. J . Chem. possible model compounds for intermediates in WGSR and/or COz-reduction catalysis.

1982,35,2445. (14)Kelly, J. M.; OConnel, C. M.; Vos, J. G. Inorg. Chim. Acta 1982, 64, L75.

(15)Collomb-Dunand-Sauthier, M.-N.; Deronzier, A. J.Electroanal. Chem. Interfacial Electrochem. 1991,319, 347.

Catalytically Active Ru-CO-bpy

Systems

Organometallics, Vol. 14, No. 2, 1995 827

bipyridine nitrogen (2.411(4)A) due to the strong trans effect of the carbonyl ligand. The Ru-N(l) bond length of 2.117(8) trans to carbonyl ligand is also slightly longer than the Ru-N(2) bond length of 2.090(8) A trans to chlorine. C-0 bond lengths are comparable with those found in [R~(bppi)(CO)2C121,~* [Ru(CO)Clz(tby)l, and [RuBr~(CO)2(tby)I.~~ Ru-C-0 angles are slightly distorted (171.1(11)-174.5(10)0) from the linear structure. Distortions of the same magnitude have been observed in [Ru(bpy)2(CO)(NOz)I+and [Ru(bpy)n(CO)CUI+ (170(1)" and 174.8(3)0,20respectively). The "bite angle" of the bipyridine is also comparable with that of other Ru-bpy c ~ m p l e x e s . ~ lWe - ~ ~did not observe any evidence of the cis(CO),trans(Cl) isomer in the crystal state. However, in the lH NMR spectrum of the pure l a crystals a trace of lb was observed. Precipitate l b was crystallized from dichloromethane only in solvated form. Crystallographic studies on l b confirmed the structure to c i s ( C O ) , t r a n s ( C l ~ - ~ R u ~ b p y ~ ( C O ~ ~ C l ~ l ~ H ~ C (Figure lb). The pale yellow crystals were highly labile and existed only under CH2Clz vapor. When the crystals were transferred in air or under a nitrogen atmosphere, they were destroyed completely within a few minutes. Unlike the use in la, the Ru-N bonds in lb are nearly equal. This is in agreement with the NMR results, which indicate symmetrical bipyridine rings. Similarly, Ru-C1 bond lengths are identical and Ru-CO bond lengths much closer to each other than in la, due to the higher symmetry of cis(CO),trans(CZ)[Ru(bpy)(CO)zClzl.In dichloromethane the IR spectrum of lb was similar to t h a t of la (Figure 2, spectrum 1). It is unlikely that both isomers truly have similar IR spectra, indicating that in solution the identities of the isomers are not proven rigorously.

A

CK3)

Figure 1. (a, top) Structure of cis(CO),cis(Cl)-[Ru(bpy)(CO)2C121(la).(b, bottom) Structure of cis(CO),trans(Cl)[ R u ( ~ ~ Y ) ( C O ) ~ C ~ ~(Ib). I.CH~C~~ (variable amounts of the component l a were also observed), which relates to the chemical equivalence of the bpy rings. lH NMR results for lb are close to those reported by Black et al.13 for the cis(CO),trans(Cl) isomer. We crystallized the pale yellow first precipitate (la) from CH2C12. The crystals were covered by a thin layer of reddish paste, which was removed by washing the crystals carefully with a small amount of CH2C12. The pure, brownish yellow crystals were used in singlecrystal X-ray diffraction studies, which confirmed the assumption of the cis(Cl),cis(CO) isomer (Figure la). Since the compound crystallizes in the centrosymmetric space group Pbca, the crystal structure contains both optical isomers. cis(CO),cis(Cl)-[Ru(bpy)(CO)~Cl~l crystallizes also in the solvated form. Crystallization from CHCl3 gave the pure optical isomer [Ru(bpy)(CO)zC121.CHC4,l6 whereas [Ru(bpy)(C0)2Clz1.CHzCl2 was again a racemic mixture.17 The coordination geometry of Ru in l a is octahedral. Both the bond lengths and the angles are quite typical €or this type of compound.lsJg The Ru-Cl(1) bond length trans to CO (2.439(3) A) is clearly longer than Ru-Cl(2) trans to (16) Crystal data for [Ru(bpy)(C0)2Clz]CHCl (la'): M , 503.56, orthorhombic, space group P212121, a = 9.192(4) b = 10.510(4)hi, c = 18.964(6)A, V = 1832(1)A3,2 = 4, D d c = 1.826 g/cm3,crystal source CHC13, c stal size 0.2 x 0.2 x 0.2 mm, yellow, Mo Ka radiation (1= 0.709 3 4 T , 28 limits 5-55", no. of unique reflections 2411, no. of observed data 1537, no. of parameters 208, p = 1.583 mm-', R = 0.0495, R, = 0.0426, GOF = 1.02. Complete structural data are available as supplementary material.

1,

Formation of [Ru(bpy)(CO)&l(C(O)OCHa)] and [Ru(bpy)(CO)zClzIin Alcohol Solution. When [Ru(CO)3C1212 was refluxed with a n excess of 2,2'bipyridine in methanol (Scheme IC),a pale yellow, nearly white precipitate was formed. Two strong IR peaks were found in the carbonyl stretching region at 2058 and 1994 cm-l (Figure 2, spectrum 2). An additional weak and broad peak was observed a t 1640 cm-l, which is typical for formyl type C - 0 stretching in metal complexes.25 The crystal structure of the product is shown in Figure 3. The [Ru(bpy)(CO)zCl(C(O)OCH3)](2) molecule consists of the symmetrical halves. The axial chlorine and the C(O)OCH3group are positioned in a mirror plane. Carbonyl ligands are (17) Crystal data for cis(CO),cis(C1)-[Ru(bpy~~CO)~C1~1CH~C1~: M, 469.12, monoclinic, space group P21/n, a = 11.446(7) A, 6 = 12.086(4) A, c = 13.204(6) A, /3 = 107.74(4)",V = 1739.7(14) A3, 2 = 4, Deale= 1.791 g/cm3,crystal source CHzClZ, crystal size 0.1 x 0.2 x 0.2 mm, pale yellow, Mo Ka radiation ( I = 0.709 34 A), 28 limits: 5-60", no. of unique reflections 5102, no. of observed data 2020, no. of parameters 199,p = 1.509 mm-l, R = 0.0790, R, = 0.0752, GOF = 1.61. Complete structural data are available as supplementary material. (18) De Munno, G.; Denti, G.; De Rosa, G.; Bruno, G. Acta CrystalZogr. 1988, C44, 1193. (19) Deacon, G. B.; Patrick, J. M.; Skelton, B. W.; Thomas, N. C.; White, B. W. Aust. J . Chem. 1984,37, 929. (20) Clear, J. M.; Kelly, J. M.; O'Connel, C. M.; Vos, J. G.; Cardin, C. J.; Costa, S. R. J. Chem. SOC.,Chem. Commun. 1980, 750. (21) Eggleston, D. S.; Goldsby, K. A.; Hodgson, D. J.; Meyer, T. J. Inorg. Chem. 1986,24,4573. (22) Greaney,M. A.; Coyle, C. L.; Harmer, M. A.; Jordan, A.; Stiefel, E. I. Inorg. Chem. 1989,28, 912. (23) Nagao, H.; Nishimura, H.; Funato, H.; Ichikawa, Y.; Howell, F. S.; Mukaida, M.; Kakihana, H. Inorg. Chem. 1989,28, 3955. (24) Durham, B.; Cox, D. I.; Cordes, A. W.; Barsoum, S. Acta Crystallogr. 1990, C46, 312. (25) Gladysz, J. A. Adv. Organomet. Chem. 1982,20, 1.

Haukka et al.

828 Organometallics, Vol. 14, No. 2, 1995

Formation of the C(0)OH ligand in other alcohol solvents was not observed. When [Ru(C0)3C1212 and 2,2’-bipyridine were refluxed in ethanol, 2-propanol, or l-heptanol (Scheme l a ) , a pale yellow precipitate was formed (a reddish color was again occasionally observed). In 1H NMR and 13C{lH} NMR measurements both la and lb peak patterns were found, suggesting that both isomers of [Ru(bpy)(CO)sCldwere formed in variable proportions. In the IR spectrum two strong peaks were found a t ca. 2067 and 2003 cm-’ (in CH2Cld, a typical spectrum for [Ru(bpy)(CO)zC121. Elemental analysis corresponded also to [Ru(bpy)(CO)2Clzl.It is likely that ethanol and alcohols with larger hydrocarbon chains are sterically incapable of forming a stable M-C(0)OR group. Another reason may be that the acidity of the alcohols tends to decrease with the increasing hydrocarbon lowering the reactivity of the OH group. In larger alcohols the chlorine bridges of the [Ru(C0)&1& dimer are probably merely broken by the addition of 2,2’-bipyridine, without further reactions with the solvent.

1

Formation of [Ru(bpy)(CO)&lIgand [Ru(bpy)(C0)2Cl€Il in Ethylene Glycol. Heating of [Ru(CO)3-

2200

2100

2000

1900

1800

1700

1600

Figure 2. IR spectra of (1) cis(CO),cis(Cl)-and cis(CO~,truns(C1)-[Ru(bpy)(CO)~C123 mixture (in CHzC12), (2) [R~(bpy)(CO)zCl(C(0)0CHdl (in CH,Cld, (3)LRu(bpyXC0)zCllz (in KBr), and (4) [Ru(bpy)(CO)2ClHI(in CH2Cld with traces of 1.

O(l1a)

Figure 3. Structure of [Ru(bpy)(CO)2Cl(C(O)OCH3)3(2). again in cis positions trans t o bipyridine nitrogens a s in lb. The Ru-CO bond lengths of 1.859(13) A are comparable with those found in la and lb. The axial Ru-Cl(1) bond is unusually long (2.496(3) A), compared with the Ru-C1 bonds in la, indicating the strong trans weakening effect of the C(O)OCH3 group. The bond lengths and angles of the Ru-(C(O)OCH3) moiety found earlier in [Ru(bpy)2(CO)(C(O)OCH3)1+ 26 are comparable with those in 2.

C1212 with a n excess of 2,2’-bipyridine in ethylene glycol (Scheme l b ) gave a red, very poorly soluble, microcrystalline precipitate (3) and a greenish black solution. When the solution was cooled to room temperature, the color lightened to reddish yellow. The IR spectrum of the solid product was completely different from those of both 1 and 2 (Figure 2, spectrum 3). The elemental analysis gave a reasonably good fit with [Ru(bpy)(C0)&112. Despite the disorder in the crystal structure, the molecular structure of 3 was verified a s a [Ru(bpy)(CO)2ClI dimer (Figure 4). The Ru-Ru bond length of 2.860(1) is comparable with those found in [Ru3(CO)d (average 2.854 A) and [Ru(CO)41n (2.860(1) A) but shorter than those found in [ R U ( ~ - C ~ H ~ ) ( C O ) ~ R U ( C O ) ~ ~ (2.889(1) A) and in [Ru(SnMe3)(C0)412(2.9430) A).28In the last two compounds the CO groups are in the eclipsed positions, whereas in [Ru(CO)41, carbonyl ligands are in staggered positions. The short Ru-Ru distance in 3 suggests that the equatorial ligands in RuL5 units may also be in staggered positions (Figure 3a). However, the crystal structure revealed also the “anti-eclipsed” rotamer (Figure 3b). The complexity of the IR spectrum (Figure 2, spectrum 3) supports the coexistence of two rotamers. The Ru-N(bpy) bond lengths vary considerably (from 2.040(6) to 2.179(7) A) in 3. Typically, the variations in these types of compounds are less than 0.1 H1.3,5,20-23 Another striking feature in 3 is the exceptionally long Ru-Cl(1) bond (2.512(1)A). A comparative bond length (2.496(3)A) is found in 2. The axial Ru-C1 bond is influenced by a strong trans effect apparently due to the C(O)O(CHd group in 2 and the Ru-Ru bond in 3. Even though the trans effect of the carbonyl group is known to be strong, the Ru-C1 bond trans to CO in la (2.439(3)A) is clearly shorter than in 3 or in 2.

x

(26)(a) Tanaka, H.; Tzeng, B.-C.; Nagao, H.; Peng, S.-H.; Tanaka, K. Organometallics 1992,11,3172. (b)Tanaka, H., Tzeng, B.-C.; Nagao, H.; Peng, S.-M.; Tanaka, K. h o g . Chem. 1993,32, 1508. (27)Olmsted, W. N.; Margolin, Z.; Brodwell, F. G. J . Org. Chem. 1980,46,3295. (28)(a) Masciocchi, N.; Moret, M.; Cairati, P.; Ragaini, F.; Sironi, A. J. Chem. SOC., Dalton Trans. 1993,471.(b) Cook, N.; Smart,L. E.; Woodward, P.; Cotton, J. D. J.Chem. SOC.,Dalton T r a n ~1979, . 1032. (c) Howard, J. A. IC;Kellet, S.C.; Woodward, P. J. Chem. SOC.,Dalton Trans. 1976,332.

Catalytically Active Ru-CO-bpy Systems

Organometallics, VoZ. 14,No.2, 1995 829

W

v

O(12)

Figure 6. Structure of [Ru(bpy)(CO)zClHI(4).

W

Figure 4. Structure of staggered (a, top) and “antieclipsed” (b, bottom) [Ru(bpy)(CO)2Cll2(3). In addition to the microcrystalline 3,other ruthenium carbonyl bipyridine compounds were also present in the ethylene glycol solution. M e r filtration of the solid 3, a reddish yellow solution was extracted with CHzC12. In the IR spectrum of the yellow extract, typically, four strong peaks were observed a t 2067, 2002, 2036, and 1965 cm-l (Figure 2, spectrum 4). The spectrum seems t o consist of two components. The ratio of these components vaned from a nearly pure “high-pair” component to a nearly pure “low-pair” component in separate syntheses. The higher pair, a t 2067 and 2002 cm-l, is probably due to [Ru(bpy)(CO)2Clzl. The lH NMR spectrum revealed that both compounds l a and l b were present. The lower pair a t 2036 and 1965 cm-l resembles the IR spectrum reported by Kelly et al. for red-purple [Ru(bpy)(CO)&l2](2040(s) and 1980 (5) cm-l in KBr).14 They suggested that these frequencies were due to the cis(CO),cis(Cl)isomer, which is in disagreement with our results. We crystallized the “low-pair” component (4) directly from ethylene glycol; the crystal structure is shown in Figure 5. N(l), N(2), Ru, C(2), and C(1) are coplanar, and the chlorine atom is above this plane. The lH NMR spectrum revealed the presence of the hydride ligand (G(Ru-H) -11.3 ppm), which

must occupy the axial position trans to chlorine. Unfortunately, we were not able to directly locate the hydride ligand in difference Fourier maps. The mononuclear ruthenium bidbipyridine) compound [Ru(bpy)n(CO)Hl+, with a hydride ligand, has been reported earlier by Vos et al.2,3(G(Ru-H) -11.47 ppm). The axial Ru-C1 bond in 4 is again exceptionally long (2.524(3) A) and comparable with those in 2 and 3. Compound 4 was easily converted t o 3 by refluxing, for example, in toluene. It is thus possible that 4 is an intermediate in the formation of 3. Glycerol was also tested as a solvent in the reaction of [Ru(C0)3Cl& and 2,2’-bipyridine. The reactions appeared to be very similar to ethylene glycol reactions. C o n v e r s i o n s of [Ru(bpy)(CO)~C121,[Ru(bpy)(CO)~CI(C(O)OCHLI)I, [Ru(bpy)(COhCl12, and [Ru(bpy)(CO)&lH]. When 2 was treated with HdCO in ethylene glycol (Scheme lg), a red precipitate was formed. According to the IR spectrum the solid product was identified as 3. CO (or HdCO) treatment of 1 (Scheme Id) did not produce considerable amounts of 3. However, traceable amounts of 3 were observed. In principle, the formation of dimer 3 from monomers requires a substitution of the axial C1 or C(O)OCH3 ligand by another Ru(bpy)(CO)&l unit. It is not surprising that a substitution of the C(O)OCH3group in 2 is easier than substitution of the chlorine in 1. For example, direct carbonylation of ruthenium chlorides is known to require relatively drastic conditions. We found that it is also possible to convert dimer 3 back to either monomer 2 or 1. When 3 was treated with CO in methanol (Scheme I n , red crystals disappeared and a pale yellow precipitate was formed. The IR spectrum of the precipitate was identical with that of 2. One would expect that a treatment of 3 with a suitable chlorine source (e.g. HC1 solution) would lead to formation of the cis(CO),trans(CZ)-[Ru(bpy)(C0)2C121 isomer. When 3 was refluxed with concentrated HC1 (Scheme le), a pale yellow precipitate was again formed. The product was soluble in dichloromethane, and two strong peaks found in the IR spectrum a t 2065 and 2004 cm-l are very close to those of [Ru(bpy)(CO)zClzlobtained directly in the THF synthesis (Scheme la). Furthermore, the lH NMR spectrum was identical with that of the cis(CO),trans(Cl)isomer of [Ru(bpy)(CO)nClzI. The behavior of [Ru(bpy)(CO)zClH]in HC1 was similar to that of [Ru(bpy)(CO)sC112. HC1 treatment of the hydride a t room temperature again yielded a yellow precipitate with NMR and IR spectra typical for cis(C~),trans(CZ)-[Ru(bpy)(CO)~C121. [Ru(bpy)(CO)aClHI was partially soluble in concentrated HC1, and when the

830 Organometallics, Vol. 14,No. 2, 1995

acid solution was allowed to evaporate to dryness at room temperature, a few dark red crystals were formed along with the pale yellow cis(CO),tru~s(Cl)-[Ru(bpy)(CO)2C12] which was the main product. Single-crystal X-ray studies on dark red crystals showed that they were also cis(CO),trans(CZ)-[R~(bpy)(CO)~Cl~l,~~ but in this case in a nonsolvated form. The odd color of these crystals may arise from impurities. One of the Ru-CO bonds was longer (1.961(11) A) than a typical ruthenium-carbonyl bond, whereas the C-0 bond was too short (0.907(15) A). Overestimation of the Ru-CO bond and underestimation of the C - 0 bond may be due to a coexistence of another complex where there is another ligand (for example, water) in the location of the carbonyl group. Conversion of [Ru(bpy)(CO)2ClHI to [Ru(bpy)(CO)nCld was also observed in chlorinated solvents such as CH2C12. The reactions shown in Scheme 1are related to those proposed by Ziessel et al. for electrocatalytic reduction of C02 with [Ru(bpy)(CO)2Clz]~ a t a l y s t . They ~ ~ , ~found that [Ru(bpy)(CO)&l2] can be reduced to the dark blue polymeric [Ru(bpy)(CO)zl, via electrolysis. A similar, dark blue and highly air-sensitive catalyst, active in WGSRg and hydroformylation,8 can also be prepared from RuQ(CO)~P and 2,2'-bipyridine. According to Ziessel, the polymer produces the [Ru(bpy)(CO)(C(O)OH)I intermediate during the electrocatalyhc cycle. In Scheme 1 we propose similar reversible reactions between the dimeric 3 and the monomeric 2 in methanol solution. Instead of changing the CO group to the C(0)OH group, a s in the reduction of C02, methanol/CO treatment of 3 leads to the cleavage of the Ru-Ru bond and formation of the C(O)OCH3 group. M-C(0)OH and M-H compounds have also been proposed a s intermediates in the WGSR cycle.4 Compounds 2 and 3 can be seen as a model compounds for these intermediates. It has also been found that Rus(CO)~P with a N E W 1 promoter is active in carbonylation of methanol to methyl formate.1° Even though the compounds synthesized in our work are different, the reversible conversions between 2 and 3 may offer a possible model route for this type of catalysis.

Conclusions Several mononuclear ruthenium bipyridine complexes can be prepared from [Ru(C0)3C1212and 2,2'-bipyridine in alcohol or THF solutions. Almost all of these complexes are directly interconvertible under suitable conditions. [Ru(bpyXC0)2Cl(C(O)OCH3)1,[Ru(bpyXCO)zC112, and [Ru(bpy)(CO)&lHI can be seen as model compounds for intermediates in WGSR and CO2 reduction, analogous to the known ruthenium bidbipyridine) complexes [Ru(bpy)z(CO)HI+ and [Ru(bpy)z(CO)(C(O)OCHd1.

Experimental Section Materials and Measurements. All reagents and solvents were p.A. grade. Alcohol solvents and concentrated HCl(37%) (29) Crystal data for cis(CO),trans(Cl)-[Ru(b yXCO)&123: M r384.18, monoclinic space group P21/n, a = 8.19 (4) b = 16.253(7) A, c = 10.463(5) A, j3 =101.54(4)", V = 1336.1(12) A3, 2 = 4, Dcdc = 1.868 g/cm3, crystal source HCl, crystal size 0.1 x 0.2 x 0.2 mm, dark red, Mo Ka radiation (,I = 0.709 34 A, 28 limits 5-50", no. of unique reflections 2430, no. of observed data 1307, no. of parameters 172, p = 1.517 mm-l, R = 0.0515, R, = 0.0473, GOF = 1.05. Complete structural data are available as supplementary material.

1,

Haukka et al. were obtained commercially and used without further purification. THF and CHzClz were dried by standard methods. Syntheses were performed under an inert atmosphere. [Ru(CO)3C12] was obtained from Johnsson & Matthey and 2,2'bipyridine from Aldrich Chemicals. Gases used in conversions of [Ru(bpy)(CO)zCl~I,[Ru(bpy)(CO)zCl(C(O)OCH3)1,and [Ru(bpy)(CO)zCl]z were high-purity grade CO (99%) and Hz (99.997%). High-pressure conversion reactions were performed in a 100 mL Berghof autoclave. FTIR spectra were recorded on a Nicolet Magna-IR 750 spectrometer and NMR spectra on a Bruker AMX-400 spectrometer (400 MHz). Preparation of [Ru(bpy)(CO)~Cl~](l). 1g of [(Ru(C0)3Clz] was dissolved in 80 mL of THF and refluxed for 2.5-3 h. A 0.75 g amount of 2,f'-bipyridine, dissolved in 20 mL of THF, was slowly added into [Ru(C0)&1212 solution. Refluxing was continued for a further 45 min, and the solution was allowed to cool to room temperature. Approximately half of the solvent was evaporated under vacuum, and the rest was stored overnight in a refrigerator. A pale yellow precipitate (la)was filtered, and the solution was transferred again to the refrig erator. After the solution stood overnight, a second precipitate (lb)was formed. The solid products were recrystallized from CHC13. The total yield was ca. 1 g (67%). Anal. Calcd for ClzHsNzOzClzRu (mol wt 384.18): C, 37.52; H, 2.10; N, 7.29; 0, 8.33. Found for la: C, 37.45; H, 2.07; N, 7.22; 0, 8.47. IR (CHZC12): v(C0) 2067(vs), 2003(vs) cm-'. 13C(lH}NMR for bpy (in CDCl3): 6 156.4, 156.0, 155.3, 151.0, 140.4, 139.7, 127.9,127.5,124.0,123.3ppm. 13C(lH}NMRfor CO: 6 195.4, 190.4 ppm (both singlets). lH NMR for bpy (in CDC13): 6 9.7 (d), 8.8 (d), 8.2 (two overlapped doublets), 8.1 (t),8.0 (t), 7.7 (t), 7.5 ppm (t). (Both NMR spectra included a variable amount of component lb.) Anal. Found for lb: C, 37.83; H, 1.95; N, 7.15; 0,8.35. IR (CHZC12): v(C0)2066 (vs), 2003 (VS) cm-l. 13C(lH}NMR for bpy (in CDCl3): 6 155.6, 153.8,140.1, 128.0,123.8 ppm (all singlets). 13C(lH}NMR for CO: 6 196.3 (s). lH NMR for bpy (in CDCl3): 6 9.2 (d), 8.3 (d), 8.1 (t),7.7 (t) ppm. (Both NMR spectra included a variable amount of component la.) Preparation of [Ru(bpy)(CO)~Cl(C(O)OCHs)l (2). A 1 g amount of [Ru(C0)3C1~]2 and 1.45 g of 2,2'-bipyridine were dissolved in 15 and 5 mL of methanol, respectively. The solutions were combined and refluxed for 30 min. A pale yellow precipitate was filtered and washed a few times with a small amount of methanol. The precipitate was dried under vacuum. The final yield was ca. 1.0 g (63%). Anal. Calcd for C&11N20&1Ru (mol wt 407.78): C, 41.24; H, 2.72; N, 6.87. Found: C, 41.29; H, 2.71; N, 6.84. IR (in CHzClz): v(C0) 2058 (vs), 1994 (vs) cm-l, 1640 (br, w) cm-l. 13C(lH}NMR for bpy (in CDCl3): 6 155.7, 153.4, 139.6, 127.4, 123.5 ppm (all singlets). 13C(lH}NMR for C(O)OCH3:6 198.2,51.9ppm (both singlets). 13C(lH}NMR for CO: 6 193.7 ppm (9). 'H NMR for bpy (in CDC13): 6 9.0 (d), 8.2 (d), 8.1 (t), 7.6 ppm (t). 'H NMR for C(0)OCHs: 6 3.4 ppm (s). Preparation of [Ru(bpy)(CO)zCl12(3) and [Ru(bpy)(CO)2CLH] (4). A 1g amount of [Ru(C0)3Cl~l~, 1.45g of 2,2'bipyridine, and 10-15 mL of ethylene glycol were placed in the reaction vessel. The mixture was heated to 90-100 "C for 1.5-2 h. The very poorly soluble red microcrystalline precipitate (3)was filtered and washed several times with THF and CHZC12. The final yield was ca. 0.18 g (14%). Anal. Calcd for C24H16N404C12RuZ (mol wt 697.46): C, 41.33; H, 2.31; N, 8.03, 0: 9.18. Found: C, 41.22; H, 2.28; N, 7.90, 0: 9.42. IR (in KBr): v(C0) 2019 (s), 2003 (w,m), 1980 (9, sh), 1970 (vs), 1937 (vs), 1910 (w,sh) cm-l. The ethylene glycol filtrate was allowed to stand under nitrogen at room temperature for several days. The reddish brown precipitate (4) was filtered, washed carefully with octanol and hexane, and dried under vacuum. The final yield was ca. 0.13 g (10%). Anal. Calcd for ClzHsNzOzClRu (mol wt 349.74): C, 41.21; H, 2.59; N, 8.01; 0, 9.15. Found: C, 41.15; H, 2.42; N, 8.02; 0, 9.14. IR (in CHzClz): v(C0) 2035 (vs), 1966 (vs) cm-l. 'H NMR for bpy (in CDC13): 6 9.0 (d),

Catalytically Active Ru-CO-bpy Systems

Organometallics, Vol. 14, No. 2, 1995 831

Table 1. Crystallographic Data for cis(CO)~is(Cl)-[Ru(bpy)(CO)~Cl~1 (la), cis(CO)/rans(Cl)-[Ru(bpy)(CO)zClz1.CH2C12 (lb), [ R ~ ( ~ P Y ) ( C ~ ) Z C ~ ( C ( ~ ) (21, O C [RU@PY)(CO)ZC~IZ H~)I (31, and [Ru(bpy)(COhClHI (4) fw cryst syst space group a, A b, A c, A

a,deg deg Y . deg

v, A3

Z Dcalc,g/cm3

cryst source cryst size, mm color radiation p, "-I

28 limits, deg h range k range 1 range no. of unique d n s no. of obsd datao no. of params Rb RwC goodness of fit a

I

2

2a(I).

la

lb

384.18 orthorhombic Pbca 12.709(4) 11.532(5) 18.852(5) 90 90 90 2763(2) 8 1.847 dichloromethane 0.3 x 0.4 x 0.4 brownish yellow

469.12 trislinic P1 6.536(4) 12.557(7) 12.595(9) 119.81(4) 93.94(6) 98.1 l(4) 876.3(9) 2 1.778 dichloromethane 0.1 x 0.2 x 0.3 pale yellow Mo Ka 1.498 5-50 0-7 -14 to +14 -14 to +14 3098 1888 199 0.0737 0.0896 1.75

Mo Ka 1.501 5-60 0-16 0-14 0-24 3148 1465 172 0.0566 0.0545 1.24

2

407.78 monoclinic P21lm

7.75 l(4) 11.863(7) 9.08 l(6) 90 107.18(4) 90 798(2) 2 1.697 methanol 0.2 x 0.3 x 0.3 pale yellow Mo Ka 1.148 4-50 0-9 0-14 -10 to +10 1459 843 109 0.0524 0.0498 1.15

w = ll(u2F R = x(IFol -- lFcl)E(lFol). 'RW = [Z(IFol- lFc1)2/~wlFo12]1'2;

Table 2. Atomic Coordinates ( x 104) and Temperature Factors (A2x 103) for cis(CO)~is(Cl)-[Ru(bpy)(CO)~Cl~l (la) atom X Y Z u" 5178(1) 4720(2) 3733(2) 6422(7) 5653(7) 4307(6) 6320(6) 3253(8) 2730(9) 3295( 10) 4365(9) 4853(8) 5989(8) 6672(9) 7708(9) 8043(9) 7333(8) 5995(9) 5524(8)

201 l(1) 2972(3) 2915(4) 4156(7) 995(8) 576(8) 1058(7) 450( 11) -503( 12) -1369(12) -1257(9) -246(9) 42(% -689(9) -367(11) 659(12) 1347(10) 3332(10) 1272(11)

3214(1) 4324(1) 2596(2) 2858(5) 1818(6) 3595(4) 3757(4) 3521(6) 3783(6) 4112(6) 4212(6) 3953(5) 4049(5) 4420(6) 4493(6) 4208(6) 3843(5) 2969(6) 2320(5)

"Equivalent isotropic U , defined as one-third of the trace of the orthogonalized Uu tensor.

3

4

697.46 monoclinic C21m 12.681(5) 10.165(3) 10.633(4) 90 114.01(3) 90 1252.0(9) 2 1.850 ethylene glycol 0.1 x 0.2 x 0.3 red

349.74 triclinic pi 6.407(3) 8.135(5) 12.707(8) 89.39(5) 81.56(5) 81.53(4) 647.4(3) 2 1.797 ethylene glycol 0.1 x 0.2 x 0.4 reddish brown Mo K a 1.389

Mo Ka 1.437 4-60 0-17 0-14 -14 to +13 1936 1393 157 0.0350 0.0341 1.05

5-55

0-8 -10 to +10 -16 to +16 3006 2321 163 0.0539 0.0609 1.03

+ 0.0005P).

Table 3. Atomic Coordinates ( x 104) and Temperature Factors (Azx 103) for cis(CO)~Uns(Cl)-[RU(bpy)(CO)zClzl.CHzClz(lb) atom

X

3212(2) 1079(6) 5387(6) -180(11) 4134(13) 936(20) 6309(20) 1161(16) 4427(15) -466( 20) -1655(22) - 1176(23) 494(24) 1606(21) 3404(20) 3994(24) 5680(23) 6751(21) 6135(19) 1832(26) 5140(24) 2239(28)

Y

z

3632(1) 1963(4) 5203(3) 1431(6) 1458(10) 5455(12) 4088( 13) 3214(10) 2254(9) 3748(12) 3509( 14) 2645(16) 2070( 15) 2365( 13) 1797(12) 830(13) 347(14) 829(12) 1776(12) 478 1( 15) 3904(15) 2315(17)

1938(1) 2008(3) 1742(4) 4857(6) 5051(7) 3715(11) 403 1(11) 350(10) 483(9) 320(13) -7 17(14) -1838(17) - 1852(14) -754( 13) -674( 12) -1679(14) - 1537(14) -384( 14) 598(13) 305 1(14) 3222(14) 5 102(16)

Ua

8.1 (d), 8.0 (t), 7.5 ppm (t) (signals of l a and lb were also occasionally found). lH NMR for H: 6 -11.3 ppm (9). Reactions of [Ru(C0)&1~1~ and 2,2'-Bipyridine in Ethanol, 2-Propanol,and 1-Heptanol. In a typical experi-

aEquivalent isotropic U , defined as one-thiid of the trace of the orthogonalized Uij tensor. Population parameter for all atoms is 0.5.

ment 500 mg of [Ru(C0)3C1~1~ and 675 mg of 2,Y-bipyridine were weighed into a 100 mL reaction vessel. A 10-20 mL amount of alcohol was added, and the mixture was deoxygenated. In the ethanol and 2-propanol reactions the mixture was refluxed for 30-45 min, and in the 1-heptanol reaction the mixture was heated to 100 "C for lh. The reaction mixture was cooled slowly to room temperature, and the yellow precipitate was filtered. The precipitates were washed a few times with small amounts of THF and dried under vacuum. The products (la and lb) were identified by IR and 'H NMR spectroscopy and elemental analysis. Conversions of [Ru(bpy)(CO)2Clzl,[Ru(bpy)(CO)zCl(C(O)OCHdI, and [Ru(bpy)(CO)zCl12in Alcohol and Acid

carried out in the 100 mL Berghof autoclave with a Teflon liner. The ruthenium monomer (100 mg) was placed in the autoclave in a nitrogen box. 1.5 mL of deoxygenated ethylene glycol, 25 bar of H2, and 25 bar of CO or 50 bar of pure CO were introduced into the autoclave. The autoclave was heated to 150 "C, and the temperature was maintained for 17 h. The red [Ru(bpy)(CO)zCl]2precipitate was filtered and washed with THF and dichloromethane. Reaction of 50 mg of [Ru(bpy)(CO)zCl]zwith 5 mL of methanol under CO was carried out under conditions similar to those above. Conversion of [Ru(bpy)(CO)zCl]zto [Ru(bpy)(C0)&12] was carried out either by refluxing [Ru(bpy)(COhCl]2 with concentrated HCl (37%) or by treating [Ru(bpy)-

Solutions. Conversionsof [Ru(bpy)(CO)zClzlor [Ru(bpy)(CO)zCl(C(O)OCH3)]monomers t o the [Ru(bpy)(CO)zCl12dimer were

832 Organometallics, Vol. 14, No. 2, 1995 Table 4. Atomic Coordinates ( x 10") and Temperature Factors (A2x 103) for [Ru(bpy)(CO)~Cl(C0oCH3)](2) atom

X

Y

Z

ua

Ru C1( 1) O(11) O(31) O(32) N(1) (31) C(2) C(3) (24) C(5) C(11) C(31) C(32)

6258(2) 8265(4) 8434(12) 4682(14) 2772(16) 4579(10) 462 1(14) 3519(16) 2352(15) 2281(11) 3412(11) 7598(14) 4438(19) 1340(24)

2500 2500 728(9) 2500 2500 3607(7) 4739( 10) 5415(8) 4936(9) 3755(10) 31 16(7) 1411(11) 2500 2500

1816(1) 4530(3) 767(9) -1548(11) -304(11) 2604(7) 2570( 10) 31 12(11) 3775(11) 383 l(9) 3246(8) 1168(10) -330(15) -1666(17)

46(1) 49(1) 120(5) 107(6) 151(8) 48(3) 6U4) 66(4) 68(5) 59(4) 44(3) 72(3 536) 154(13)

OEquivalent isotropic U , defined as one-third of the trace of the orthogonalized UOtensor.

Table 5. Atomic Coordinates (x104) and Temperature Factors (A2x 103) for [Ru(bpy)(CO)zCl]z(3) atom

X

Y

Z

Ru CK1) O(11) O(12) NU) N(2) C(1) C(2) (33) C(4) C(5) C(6) C(7) C(8) C(9) C(10) C( 11) C(12)

4056( 1) 2474(1) 3600(5) 2515(5) 4520(5) 5157(5) 4123(6) 4345(7) 5006(8) 54 13(7) 5125(10) 5525(5) 6222(6) 6496(7) 6090(7) 5462(10) 3769(6) 3128(5)

0 0 -2856(6) 839(6) 1776(6) -588(6) 2948(7) 4123(8) 4090(9) 2915(9) 1826(23) 444(7) 226(35) -1031(11) -2088(9) -1759(26) -1801(8) 487(7)

3 6 7 3 1) 1292(1) 4349(6) 5017(6) 3163(6) 2647(6) 3390(8) 2902(9) 2139(10) 1884(8) 2334(23) 2144(6) 1404(7) 1204(8) 1697(8) 2479(24) 4095(7) 4521(6)

'

ua 38(1) 5 ~ 1 ) 6W) 64m 43(2) 4 w 51(3)

64(4) 73(4) 57(3) 34(4) 43(3) 54@) 59(3) 61(3) 43(5) 460) 45(2)

"Equivalent isotropic U defined as one-third of the trace of the orthogonalized Ui, tensor. Population parameter for all atoms is 0.5.

Table 6. Atomic Coordinates ( x 10") and Temperature Factors (A2x 103) for [Ru(bpy)(CO)zClH](4) atom

X

Y

Z

Ua

1322(1) -432(2) -252(7) 3472(7) 4096(9) - 1774(9) 3043(11) -64 1( 11) -2165( 10) -3060(11) -1988(11) -75(11) 789(9) 2848(9) 4087(11) 6020(12) 6687(10) 5376(9)

1329(1) 2428(2) -777(6) -270(6) 3934(8) 3174(8) 2964(9) 2493(8) -956(8) -2397(9) -3672(8) -3481(8) -2030(7) - 1723(7) -2846(9) -2483(10) -1021(9)

3119(1) 1548(1) 3056(4) 2019(4) 3289(6) 4880(5) 3194(6) 4192(6) 3630(5) 3587(6) 2927(7) 2313(6) 2396(5) 1804(5) 1074(6) 554(6) 798(5) 1520(5)

38(1) 46(1) 40(1) 38(1) 95(3) 78(2) 58(2) 53(2) 50(2) 57(2) 61(3) 56(2) 41(2) 43(2) 60(2) 62(2) 52(2) 45(2)

aEquivi nt isotropic orthogonalized U, tensor.

5X8)

defined as one-i-ird of the trace of the

(C0)2Cl~l with HCl in an autoclave using elevated temperature (200 "C for 2 h). The solid products were identified with IR spectroscopy and elemental analysis. X-ray Data Collection and Structure Solution for cie(CO),cie(CZ)-[Ru(bpy)(CO)~C121 (la), cis(CO),trane(CZ)[R~(bpy)(CO)zClzl.CHzClz (lb), [Ru(bpy)(CO)2Cl(C(O)OC&)I (2), [Ru(bpy)(CO)~Cll~ (31,and [Ru(bpy)(CO)2ClHl

la Ru-Cl(1) 2.439(3) R U - C ~ ( ~ ) ~ 2.41 l(4) Ru-N(l) 2.117(8) Ru-N(2) 2.090(8) Ru-C(l1) 1.899(11) Ru-C( 12) 1.841( 16) Ru-C(31) 1.938(10) C( 11)-O( 11) 1.115(14) C( 12)-O( 12) 1.123(20) C(31)-0(31) 1.012(15) C(3 1)-O(32) 1.299(20) 0(32)-C(32) 1.397(17) Ru-Ru 2.860( 1) L2

lb

2

3

4

2.391(5) 2.390(5) 2.112(12) 2.102(9) 1.835(17) 1.817(8) 2.041(12) 1.133(22) 1.159(11) 1.175(18)

2.496(3)

2.512(1)

2.524(2)

2.117(8) 2.040(6) 2.179(7) 2.120(5) 1.859(13) 1.953(8) 1.860(8)

2.118(4) 1.874(6)

1.161(16) 1.148(10) 1.142(8) 1.130(10)

Cl(2) = Cl(3) for lb.

Table 8. Selected Bond Angles (deg) for cis(CO),cis(Cl)-[Ru(bpy)(CO)~Cl~l (la), ~ i s ( C 0 ) ~ ~ n ~ ( C l ) - [ R ~ ( b p y ) ( C O ) z C l z ] ~(lb), H~Clz [Ru(~PY)(CO)ZC~(COOCH~)I (2), [RuO~PY)(CO)ZC~IZ (317 and [Ru(bp~)(CO)zClHl(4) la Cl( l)-Ru-C1(2)* 92.1(1) Cl(l)-Ru-N(l) 86.5(2) C1( l)-Ru-N(2) 89.1(2) Cl(l)-Ru-C(ll) 88.5(3) Cl( l)-Ru-C( 12) 95.0(2) C1( 1)-Ru-C(3 1) 178.8(3) 96.0(2) N(l)-R~-c1(2)~ 77.6(3) N(l)-Ru-N(2)" 174.1(4) N(l)-Ru-C(ll) 95.0(6) N(l)-Ru-C(12)" 94.0(4) N(l)-Ru-C(31) N ( ~ ) - R u - C ~ ( ~ ) ~ 89.1(2) 99.3(4) N(2)-Ru-C(11) 172.1(6) N(2)-Ru-C( 12) 92.1(4) N(2)-Ru-C(31) 88.5(3) C(ll)-R~-C1(2)~ 90.2(7) C(ll)-Ru-C(12)" 91.0(5) C(ll)-R~-C(31) C(12)-Ru-C(31) 174.5(10) Ru-C(ll)-O(ll) Ru-C(12)-0(12) 177.9(13) 171.1(11) Ru-C(31)-0(31) Ru-C(31)-0(32) 113.2(10) C(31)-0(32)-C(32) 117.0(11) Ru-Ru(A)-Cl( 1) 177.0(1)

lb

2

3

176.3(1) 89.4(4) 87.3(3) 91.0(6) 98.4(2) 175.2(5) 88.9(4) 77.2(4) 174.8(6) 97.7(5) 90.1(4) 89.2(3) 97.6(6) 179.6(2)

94.3(3) 171.9(2)

97.2(3)

88.0(8)

85.6(3)

87.8(3)

86.1(2) 84.6(1) 94.0(3)

86.0(1) 87.3(1) 94.8(2)

4

86.6(1) 97.9(2)

76.6(5) 78.2(2) 77.0(2) 174.3(5) 172.3(3) 172.5(2) 101.9(3) 97.5(2)

89.5(4) 178.6(15) 179.7(8) 179.6(8) 176.7(7) 177.0(6) 176.7(7) 129.8(11)

"N(2) = N(1a) and C(12) = C(l1a) for (2). bC1(2) = Cl(3) for (lb).

(4). Suitable crystals of la, 2, 3, and 4 were mounted on a glass fiber, whereas a crystal of l b was sealed into the glass capillary to prevent decomposition. Data were collected at 20 "C on a Nicolet R3m diffractometer using the 0-scan data collection mode and Mo Ka radiation (1= 0.710 73 A, graphite monochromatized). Accurate cell parameters were obtained from 25 automatically centered reflections. Intensities were corrected for background, polarization, and Lorentz factors. Absorption correction was made from +scan data for 3,the maximum and minimum transmission factors being 0.3764 and 0.4365, respectively. All structures were refined in centrosymmetric space groups, which led t o satisfactory results. Originally, structure 2 was solved in space group P21 and structure 3 in space group C2. However, in both cases the refinement of the structures in these space groups led to unsatisfactory results. Moreover, in 3 disorder was found in space group C2 equal to that in C2lm. The refinement of 3 did not succeed at all in space group Cm. In structure 2 the (30) Sheldrick, G. M. SHELXTL PLUS, release 4.11N Siemens Analytical X-ray Instruments: Madison, WI, 1990.

Catalytically Active Ru-CO-bpy

Organometallics, Vol. 14, No. 2, 1995 833

Systems

anisotropic thermal parameters of O W ) , 0(31), 0(32), and C(32) remained large in the final refinement because of the displacement of the atoms perpendicular to the mirror plane (Figure 3). However, no disorder across the mirror plane was observed. After final refinement of structure 3,all atoms not located in the mirror plane were found in two positions with equal occupation parameters (0.5),due to disorder. When both possible atom positions were chosen separately, two rotamers were obtained, as shown in parts a and b of Figure 4. The structures of l a and 3 were solved by direct methods and those of 2 and 4 by Patterson synthesis with subsequent Fourier synthesis with use of the SHEIXTL program package.30 All non-hydrogen atoms were refined anisotropically. Aromatic hydrogens were placed in idealized positions (C-H = 0.96 A,

U = 0.08 k ) and not refined. Crystallographic data are summarized in Table 1. Supplementary Material Available: Tables of bond lengths and angles, anisotropic displacement coefficients, and H-atom coordinates for la,b and 2-4, tables of crystallographic data, atomic coordinates, bond lengths and angles, and anisotropic displacement coefficients for [Ru(bpy)(CO)zClzICHC13,[Ru(bpy)(CO)zClzlCHzClz,and [Ru(bpy)(CO)zClz], and figures giving the structures of l b and the last three compounds mentioned (26 pages). Ordering information is given on any current masthead page.

OM9403636