5158
Inorg. Chem. 1992, 31, 5158-5159
Synthesis, Properties, and Crystal Structure of a Novel p-Hydrazine-Bridged Mixed-Valence Ruthenium(I1,III) Complex Stabilized by Hydrazine Hydrogen Bonds, [RUCI(TMP)~]~(~-CI)(~-N~H~) ( p - S 2 ) (TMP = P(0Me)S) Masaki Kawano, Chikara Hoshino, and Kazuko Matsumoto' Department of Chemistry, Waseda University, Tokyo 169, Japan Received July 9, 1992 Transition metal complexes with coordinated hydrazine are microcrystallineproduct" formed and was filtered. The product was recrystallized from CH2C12/ether; yield 0.18 g, 60% (0.23 currently of considerableinterest as possible intermediates in the g, 80% with the use of anhydrous hydrazine). The hydrazine chemistry of coordinated dinitrogen and its reduction to NH3 derivative RHNNHR seems to undergo the reaction shown in catalyzed by nitrogenases.1-4 Numerous complexes with coorScheme Ia and/or Scheme Ib, though we have not been able to dinated hydrazine or its derivatives have been synthesized, but obtain the reaction products, R2NNR2, RCl, and R2NNHR. The only a few complexes are known which have been characterized stoichiometriesof the reactions shown in Scheme I seem probable, by X-ray crystallography: coordinated NNH2, [Mo(NNH2)since the reaction does not proceed when only equimolar F(dpe)2](BF4).CH2C12 (dpe = Ph2PCH2CH2PPh2),4E [WC13RHNNHR is added. The reaction proceeds successfully only (NNH2)(PMe2Ph)2];Mp-N2H2,[p-N2H2(Ru(PPh3)dttdj23(dttd when the molar ratio of RHNNHR to 2 exceeds 2: 1. The overall = 2,3,8,9-dibenzo-1,4,7,lO-tetrathiadecane(2-));s q-N2H3-, stoichiometryof the reaction with NH2NH2 is shown in Scheme W(NAr) [N(NTs)2] (q-NHNH2)Cl (Ar = 2,6-Cs&-i-Pr2; I, parts c and d. Hydrazine hydrochloride salts were identified N(NTs)2 = 2,6-NCsH3(CH2NTosyl)2),WCp*Me4(q-NHNH2),7 6 by and [WCp*Me3(~NHNH2)] (S03CF3)(Cp* = V ~ - C ~ M and~ ~ ) ; ~ IR spectroscopy and elemental analysis. The molecular structure of 1is shown in Figure 1.I4 Compound p3-N2H3-, (~-H)Ru~(CO)~(~~-NHNH~).~ Coordinated N2H4 1 is a 35 electron dimer and yet lacks a direct metal-metal bond moietiesare even more scarce: to our knowledge, only [W(NPh)(Rue-Ru, 3.800 (1) A). The literature values of sulfur-sulfur Mej]2(p-ql,q1-NH2NH2)(p-q2,q2-NHNH),9a [(tripod)Co(q2distances in disulfide complexes are mostly in the range 2.01N2H4)I2+(tripod = C H S C ( C H ~ P P ~and ~ ) ~[MoFe3S4C12(C15),~~ 2.05 A.15 The S S distance of 2.002 (3) A in 1 is, therefore, cat)12(p-S)(p-N2H4)(cat = catecholate)I0 compounds contain relatively short and lies between the values of free S2(1.887 A)16 the N2H4 ligand and have been structurally elucidated by X-ray and H2S2 (2.055 &,I7 indicating the partial double-bond character diffraction, but the structures of latter two complexes have not of the pS2 unit in 1. Double-bond character is also indicated for been well determined due to the poor quality of the crystals. We the R u S bonds. They are comparatively shorter (2.266 (2) and report here the synthesis, the properties, and the crystal structure 2.296 (2) A) than the R u S bond distances as found in [(NH&of [RuCI(TMP)~]~(~-C~)(~-N~H~)(~-S~) (1) (TMP = trimethRu1'{S(CH3)(C2Hs))](PF6)2 (2.316 (1) A),I8 [(NH~)~RuII'ylphosphite), the first mixed-valenceruthenium(I1,III) complex, {S(CH3)(C,H,))] (PF6) ].s( F) l.s (2.37 11 (5) &,I9 and the S-bound in which C1-, NH2NH2 and a strong *-donor ligand, Sz2-,bridge thiophene complex [ (2-(SC4H3) CH2C5H4)Ru"( PPh3) 21 (BF4) two ruthenium centers. (2.408 A).20 The S S and R u S bond distances in 1 are longer Compound 1 was synthesized by the reaction of [RuWIthan the corresponding ones in 2 (34e; S S , 1.971 (4) A, R u S , (TMP)J2(p-C1)2(p-S2) (2)11(0.30g,0.33 mmol) with RHNNHR 2.205 (2) A, and 2.198 (2) A), while the S S and R u S distances (R = SiMe3) (145 pL, 0.67 mmol)12 or anhydrous hydrazine in 1 are, respectively, shorter and longer than those in [(NH3)5(22.2 pL, 0.68 mmol) in 10 mL of dichloromethane at 0 OC for Ru]2(p-S2)C14.2H20 (34e; S S , 2.014 (1) A, and R u S , 2.191 12 h. The color of the solution gradually changed from green to (1) and 2.195 (1) A).21.22As Rauchfuss et aL2)have suggested, yellowish-brown. When NHzNH2 was used, the reacted solution *-donation from sulfur to ruthenium is invoked in electronwas filtered in order to remove which powders of NH2NHynHCl deficient complexes, thus causing shorter R u S distances. The ( n = 1 or 2). Diethyl ether was slowly added to the solution. short R u S distances in 1 (35e dimer) are therefore caused by After the solution stood at 0 OC for 3 d, reddish-brown such strong *-donation of the coordinated S22-ligand. The mixedvalence interaction between the two metal centers is obviously Pelikan, P.; Boca, R. Coord. Chem. Rev. 1984,55,55-112, and references therein. Henderson, R. A.; Leigh, G. J.; Pickett, C. J . Adv. Inorg. Chem. Radiochem. 1983, 27, 198-291 and references therein. Chatt, J.; Dilworth, J. R.; Richards, R. L. Chem. Rev. 1978, 78, 589625. (a) Dilworth, J. R.; Richards, R. L. In Comprehensive Organometullic Chemistry; Wilkinson, G., Stone, F. G. A., Abel, E. W., Eds.; Pergamon: Oxford, England, 1982;Chapter 60,pp 1073-1106. (b) Hidai, M. In Molybdenum Enzymes; Spiro, T. G . . Ed.; J. Wiley: New York, 1985;p759. (c) Hidai, M.; Kodama, T.; Sato, M.; Harakawa, M.; Uchida, Y. Inorg. Chem. 1976,15, 2694. (d) Chatt, J.; Fakley, M. E.; Hitchcock, P. 9.; Richards, R. L.; Luong-Thi, N. T. J . Organomet. Chem. 1979, 172, C55. Sellmann, D.; Bohlen, E.; Waeber, M.; Huttner, G.; Zsolnai, L. Angew. Chem., Int. Ed. Engl. 1985, 24, 981-982. Cai, S.;Schrock, R. R. Inorg. Chem. 1991, 30, 4106-4108. Schrock, R. R.; Liu, A. H.; ORegan, M. B.; Finch, W. C.; Payack, J. F. Inorg. Chem. 1988, 27, 3574-3583. Jenke, T.;Stocckli-Evans. H.; Suss-Fink, G. J . Orgunomet. Chem. 1990, 391, 395402. (a) Blum, L.; Williams, 1. D.; Schrock, R. R. J . Am. Chem. SOC.1984, 106,8316. (b) Vogel, S.;Barth, A.; Hutter, G.; Klein, T.; Zsolnai, L.; Kremer, R. Angew. Chem., Int. Ed. Engl. 1991, 30, 303. Challen,P.R.;Sang-ManKoo;Kim,C.G.;Dunham, W. R.;Coucouvanis. D. J . Am. Chem. SOC.1990, 112, 8606-8607. Matsumoto, T.; Matsumoto, K. Chem. Lett. 1992, 559-562. Seppelt, K.; Sundermeyer, W. Chem. Eer. 1969, 102, 1247-1252.
Anal. Calcd for C I ~ C I ~ H ~ ~ N ~ O(MW ~ ~ P=~900.97): R U ~ SC, I 16.00; H, 4.48;N , 3.12. Found: C, 15.88;H, 4.46;N , 3.12. Crystal data for C12CI,H,oN2OI2P4Ru2S2 a t 23 OC: monoclinic, space group P21/c, u = 17.850 (3) A, b = 12.468 (2) A, c = 16.497 (4)A, B = 115.07 (I)', Z = 4,palE = 1.800 g cm-I, p = 14.88 cm-I. A total of 7889 reflections were collected in the range 5O< 28 < 5 5 O ( a h , k , l ) . Of these, 5296 were unique and 3897 with F, > 5.00a(F0)were used in the structure solution. R(F) = 0.057,R(FJ = 0.062 (w = l/(u(F)2 + 0.001922P)). All non-hydrogen atoms were anisotropically refined. The positions of the N H 2 N H 2hydrogen atoms were located by difference Fourier synthesis in the final step and were not refined. Muller, A,; Jagermann, W.; Enemark, J. H. Coord. Chem. Reo. 1982, 46, 245. Meyer, B. Chem. Rev. 1976, 76, 367. Winnewisser, G.; Winnewisser, H.; Gordy, W. J . Chem. Phys. 1968,49, 3465. Krogh-Jespersen, K.; Zhang, X.;Ding, Y.; Westbrock, J. D.; Potenza, J. A.; Schugar, H. J. J. Am. Chem. SOC.1992, 114,4345. Krogh-Jespersen, K.; Zhang, X.;Westbrock, J. D.; Fikar, R.; Nayak, K.;Kwik, W-L.;Potenza, J.A.;Schugar, H. J.J. Am.Chem.Soc.1989, I l l , 4082. Draganjac, M.; Ruffing, C. J.; Rauchfuss, T. B. Orgunometullics 1985, 4, 1909. Kuehn, C. G.;Taube, H. J . Am. Chem. SOC.1976, 98, 689. Elder, R. C.; Trkula, M. Inorg. Chem. 1977, 16, 1048. Amarasekera, J.; Rauchfuss, T. B.; Wilson, S.R. Inorg. Chem. 1987, 26, 3328-3332.
0020-166919211331-5158%03.00/0 0 1992 American Chemical Society
Communications
Inorganic Chemistry, Vol. 31, No. 25, 1992 5159
Scheme I
0 .
a
P4
?
t 1.75Nt!=$dH2
2.25Nt!=$dH2
(1) + 0.5NzH,-2HCI + 0.25Nzf
(1) + N,H,-HCI
+ 0.25Nzt
(C)
(d)
Figure 2. Association of two enantiomers via N-H-CI hydrogen bonds (methoxy groups omitted for clarity).
error, the border value of 2.89 (2) A suggested by Kuleshova et al.2*as indicative of a hydrogen bonding. In the unit cell, two enantiomers of 1 are related by a center of symmetry and are associated via two NH-Cl hydrogen bonds to give a cyclic centrosymmetric tetramer (Figure 2). The C5 N1-4212 distance is 3.237 (7) A, which is comparable to the NH-Cl bond distance of 3.23 A, which is in ref 29 reported as the border value of a hydrogen bond. The visible spectrum is dominated by an absorption at 8 12 nm (t = 3.35 X lo3 M-I cm-I), which can possibly be attributed to Figure 1. Molecular structure of [RuCI(TMP)~]~(~-CI)(~-NZH~)(~Sz) (H atoms omitted for clarity except hydrazine hydrogen atoms). intervalence charge transfer.30 The replacement of C1- in 2 (A, = 737 nm, t = 5.82 X 103M-' cm-I) by N2H4 results in a red-shift of 75 nm. The EPR spectrum in dichloromethane at 77 K shows mediated by the disulfideligand. The Ru-P distances in 1,2.223 a rhombic pattern (gl = 2.12, g2 = 2.07, g3 = 1.989). No signal (3) (trans to Cll), 2.221 (2) (trans to Nl), 2.223 (3) (trans to was observed at room temperature. N2), and 2.210 (3) A (trans to Cll), are 0.02-0.03 A shorter The cyclic voltammetry of 1 revealed a single reversible redox than those (all trans to bridging chloride) in 2,2.242 (3), 2.248 wavecorrespondingto Ru( 11)-Ru(III)/Ru(III)-Ru(111) at -0.09 (3), 2.258 (2), and 2.252 (2) A. The decrease of Ru-P distances V vs Ag/AgCl (Fco/+ = 0.45 V),31 The reversible half-wave is ascribed to the increase of back-donation of Ru(tZg) to P(A), potential of the starting material for 2, tr~ns-RuCl~(TMP)~, is since the electron density on the ruthenium atoms is increased 0,77VvsAg/AgCland thatof2is4.21 V. Theselargecathodic by le reduction. Both Rul-P and Ru2-Pdistances are shortened shifts from the mononuclear to binuclear compounds are due to to an approximately equal degree. This fact suggests that the a strong *-donating contribution of the S22- ligand. A similar unpaired electron delocalizes over the Ru& core. The shortest largecathodicshift was reported for [(CpRu(PPh3))2(r-S~)](BF4)2 Ru-Cl (bridging) distance, 2.477 (2) A, is longer than both (-0.875 V vs Ag/AgCl) compared to CpRU(PPh3)2C1(0.597V terminal Ru-Cl bonds, 2.454 (2) and 2.430 (2) A, as expected. vs. Ag/AgC1).23 As expected from the redox potential, the The R u S S - R u torsion angle in 2 is 0.4 (2)O, whereas that in yellowish-brown solution of 1is readily oxidized in air and turns 1 is 16.1 (2)O. The increased torsional distortion in 1 is due to greenish-blue. The isolation of theoxidized complex is in progress. the staggered conformation of Rul-N1 and Ru2-N2 (the RuThe present study indicates the capability of the Ruz(pC1)N-N-Ru torsion angle is 56.5 (7)O). ( ~ 4 2 )core to capture a hydrazine molecule and the existence of The N-N distance of 1.442 (1) A is comparable to those of significant inter- and intramolecular hydrogen bonds of the [W(NP~)M~~IZ(~-~~,~~-NHZNH~)(~-~~~,~~-NHNH) (NHrNH2, coordinated hydrazine in 1. The reactivities of the complex and 1.434 (14) A; cf. NH-NH, 1.391 (15) A)9a and [(tripod)Cothe coordinated hydrazine are now under investigation and will (a2-N2H4)]2+(1.446 (17) A)9band falls in the range found for be reported separately. 7-coordinated organohydrazinesR,N2H(em) (m= 1, 2).24325 The Ru-NH2 bond distances of 2.170 (7) and 2.172 (7) A in 1 are Acknowledgment. The present study is financially supported slightly longer than a Ru-N bond of 2.12 A which is a sum of by a Grant-in-Aid for Scientific Research on Priority Area of the covalent radii of Ru and N, 1.4226 and 0.70 A,Z7respectively. 'Activation of Small Molecules" (04241225) from the Ministry This is probably due to the trans influence of P(OMe)3. In the of Education, Science, and Culture, Japan. IR spectrum of a CH2C12 solution, two NH symmetric and Supplementary Material Available: Tables of crystal data and data antisymmetric stretches are observed ( v = 3316, 3244 cm-1) as collection and refinement detail, positional parameters, anisotropic thermal expected for symmetric NzH4. However, the IR spectrum (KBr parameters, and bond distances and angles for 1 and a figure showing pellet) showed four bands (v = 3304,3240,3204,3132 cm-I) in the ESR spectrum of 1 (8 pages). Ordering information is given on any theNH stretchrange. N1.-01 andN2-.012distancesare 2.765 current masthead page. (10) and 2.936 (10) A, respectively. The close approaches of N1 (28) Kuleshova, L. N.; Zorkii, P. M. Acta Crystallogr. 1981, E37, 1363to 0 1 and N2 to 012 are comparable to, within experimental
c2
c11
(24) Bailey, N. A.; Frisch, P. D.; McCleverty, J. A.; Walker, N. W.; Williams, J. J. Chem. SOC.,Chem. Commun. 1975, 350. (25) Bultitude, J.; Larkworthy, L.F.; Povey, D. C.; Smith, G. W.; Dilworth, J. R.; Leigh, G. J. J. Chem. SOC.,Chem. Commun. 1986, 1748. (26) Howard, J.; Woodward, P. J. Chem. Soc., Dalton Trans. 1975, 59. (27) Bennett, M. J.; Mason, R. Nature 1965, 205,760.
1366. (29) Pimentel, G.C.; McClellan, A. L. The Hydrogen Bond; Freeman: San Francisco, CA, 1960. (30) SchrMer, M.;Stephenson, A. In ComprehensiueCoordinationChemistry, Wilkinson, G., Gillard, R.D., McCleverty, J. A., Eds.; Pergamon: Oxford, England, 1987; Chapter 45, pp 31 1-320. (31) The cyclic voltammetry was measured in dichloromethane with a Pt
working electrode and n-BulNCIO, supporting electrolyte.
