DALTON J. Chem. Soc., Dalton Trans., 1997, Pages 2341–2345 2341 Synthesis of novel ruthenium complexes containing bidentate imidazole-based ligands Sarah Elgafi, Leslie D. Field,* Barbara A. Messerle,* Trevor W. Hambley and Peter Turner School of Chemistry, University of Sydney, Sydney, NSW 2006, Australia Ruthenium(II) complexes containing the bidentate imidazole-based ligands (MeN2H2C3)2CO L1, (MeN2H2C3)2CHOH L2 and (MeN2H2C3)2CH2 L3 (where 1-MeN2H2C3 = 1-methylimidazol-2-yl), [Ru(PPh3)2H(CO)L1]Cl 1, [Ru(PPh3)2H(CO)L2]Cl 2 and [Ru(PPh3)2H(CO)L3]Cl 3, were synthesized by the reaction of L1–L3 with [Ru(PPh3)3H(Cl)(CO)] in toluene.The complexes were characterised by NMR spectroscopy and the crystal structures of [Ru(PPh3)2H(CO)L1]BF4 4 and [Ru(PPh3)2H(CO)L2]OH 5 determined. Transition-metal complexes with ligand systems containing nitrogen-donor atoms have been used successfully to promote the transformation of organic compounds,1 and also to act as structural mimics of metal centres in enzymes.2–5 Ruthenium complexes containing bidentate N-donor ligands with sp2- hybridised nitrogen atoms such as 2,29-bipyridyl,6 1,10- phenanthroline 6 and bis(pyrazol-1-yl)methane 7 have recently found use in catalytic hydrogenation reactions. Research into transition-metal complexes containing polyimidazole ligands has been concerned primarily with metalloenzyme mimicry, using metal complexes of zinc,2,8 iron,9,10 cobalt 2,8 and copper.11 A number of palladium,12,13 platinum14 and ruthenium 15 complexes of polyimidazole ligands have also been reported. In particular, platinum complexes of the bidentate imidazoles (MeN2H2C3)2CO L1 and (MeN2H2C3)2CHOH L2 where MeN2H2C3 = 1-methylimidazol-2-yl have been reported and show considerable cytostatic activity.16 Palladium( II) complexes of the bidentate ligand (MeN2H2C3)2CH2 L3 and closely related symmetrical and unsymmetrical bidentate N-donor ligands with pyridine, pyrazole and imidazole subunits have been investigated in detail.13 In this paper, we report the syntheses and structures of novel ruthenium(II) complexes of L1,9,13,17 L2,4 and L3.13 The complexes [Ru(PPh3)2H(CO)L1]Cl 1, [Ru(PPh3)2H(CO)L2]Cl 2 and [Ru(PPh3)2H(CO)L3]Cl 3 are readily formed by reaction of the appropriate L with [Ru(PPh3)3HCl(CO)] in toluene solvent.The complexes are charged and are of the general form [RuL- (PPh3)2H(CO)]Cl in which a single bidentate imidazole ligand L is bound to the metal centre with displacement of triphenylphosphine and Cl2 ligands from the precursor.The complexes were characterised by NMR spectroscopy and [Ru(PPh3)2- H(CO)L1]BF4 4 and [Ru(PPh3)2H(CO)L2]OH 5 were characterised by X-ray diffraction. Results and Discussion Ligand synthesis The bidentate ketone L1 was synthesized by deprotonation of N-methylimidazole and reaction with diethyl carbonate at low temperature using a modification of the procedure described by Lippard and co-workers.17 Although L1 has been synthesized using other methods,9,13,17 this route gave yields which were consistently above 60%. Bidentate ketones analogous to L1 have also been reported previously as intermediates in the synthesis of tridentate imidazoles.5,18 The bidentate alcohol L2 was synthesized by a modification of the method described by Breslow and co-workers.4 The bidentate alkane L3 was prepared following the method of Byers and Canty,13 by Wolff–Kishner reduction of L1.Synthesis of metal complexes Carbonylchlorohydridotris(triphenylphosphine)ruthenium(II) 19 [Ru(PPh3)3H(Cl)(CO)] was used as the precursor for the synthesis of ruthenium complexes. We have previously shown that tridentate imidazoles form clean products from this precursor,20 where only one tridentate ligand binds to the metal centre. The synthesis of the metal complexes containing bidentate imidazole ligands L involved refluxing solutions of [Ru(PPh3)3- H(Cl)(CO)] with each L in toluene solution over a period of hours, and isolation of the products.In all cases a single bidentate imidazole ligand L binds to the metal centre with displacement of PPh3 and Cl2 from the precursor. The resulting com-2342 J. Chem. Soc., Dalton Trans., 1997, Pages 2341–2345 plexes [RuL(PPh3)2H(CO)]Cl are charged and precipitate directly from the reaction mixture. Crystals of [Ru(PPh3)2H(CO)L1]1 cation containing the ligand L1 were obtained by addition of sodium tetrafluoroborate to a methanol solution of complex 1, giving the tetrafluoroborate complex 4.Crystals of the hydroxide salt, [Ru(PPh3)2- H(CO)L2]OH 5 were formed on slow crystallisation of [Ru- (PPh3)2H(CO)L2]Cl2 2 from methanol–water. Hydroxide resulted from exchange of Cl2 with water during recrystallisation. The complexes 1–3 have been analysed using NMR spectroscopy. Two-dimensional NMR techniques were used for assigning the resonances and determining the stereochemistry of the products.The structures of 4 and 5 were confirmed using single-crystal X-ray analysis. Projections of the structures of [Ru(PPh3)2H(CO)L1]BF4 4 and [Ru(PPh3)2H(CO)L2]OH 5 are shown in Fig. 1. Selected structural parameters are given in Table 1, crystallographic details in Table 2. Crystal structures The two complexes 4 and 5 have similar distorted-octahedral geometries about the metal centre. The P]Ru bonds are not collinear, with the P]Ru]P angle distorted by about 108 from linearity [171.6(4) for 4 and 168.9(6)8 for 5].The bite angle of the bidentate imidazole ligand is small, with bond angles Fig. 1 The ORTEP21 plots of (a) [Ru(PPh3)2H(CO)L1]BF4 4 and (b) [Ru(PPh3)2H(CO)L2]OH 5 with 30% thermal ellipsoids for the nonhydrogen atoms; hydrogen atoms have an arbitrary radius of 0.1 Å. Both complexes are viewed with the P]Ru]P axis lying horizontal N]Ru]N of 83.2(1)8 in 4 and 84.7(2)8 in 5. The two triphenylphosphine ligands lean towards the CO ligand and away from the imidazolyl rings of the ligand, with the angles between the P]Ru and C]Ru bonds on average less than 908 [85.9(1), 89.9(1) in 4, 88.1(2) and 92.8(2)8 in 5], and the angles between the P]Ru and N]Ru bonds larger than 908 [94.18(2) and 91.91(9) in 4, 98.3(1) and 92.4(1)8 in 5].The imidazolyl rings of complex 4 are planar to within 0.01 Å and form dihedral angles of 21.3 and 18.68 with the coordination plane defined by N(1)]N(2)]C(1) and H(Ru).The metal ion is slightly displaced from the co-ordination plane, by 0.03 Å. Atoms N(1), N(2) and C(1) reside on the least-squares plane, whereas H(1Ru) deviates from it by 0.02 Å. The imidazolyl rings of 5 are also planar to within 0.01 Å and form dihedral angles of 9.7 and 11.08 with the co-ordination plane defined by N(1), N(2), C(1) and H(Ru). The metal ion is 0.02 Å out of this plane. Atoms N(1), N(2) and C(1) of 5 reside on the least-squares plane, whereas H(Ru) deviates from it by 0.03 Å.Table 1 Selected bond distances (Å) and angles (8) for complexes [Ru(PPh3)2H(CO)L1]BF4 4 and [Ru(PPh3)2H(CO)L2]OH 5 Ru]N(1) Ru]N(2) Ru]P(1) Ru]P(2) Ru]CO Ru]H P(1)]Ru]P(2) P(1)]Ru]N(1) P(1)]Ru]N(2) P(1)]Ru]C(1) P(2)]Ru]C(1) N(1)]Ru]N(2) 4 2.176(3) 2.135(3) 2.357(1) 2.356(1) 1.829(4) 1.66(4) 171.61(4) 94.18(9) 91.91(9) 85.9(1) 89.9(1) 83.2(1) 5 2.181(5) 2.139(5) 2.336(2) 2.385(2) 1.845(7) 1.77(5) 168.96(6) 98.3(1) 92.4(1) 88.1(2) 92.8(2) 84.7(2) Table 2 Crystallographic data * for [Ru(PPh3)2H(CO)L1]BF4 4 and [Ru(PPh3)2H(CO)L2]OH 5 Empirical formula M Crystal colour, habit Crystal dimensions/mm a/Å b/Å c/Å b/8 U/Å3 Dc/g cm23 F(000) m/cm21 2qmax/8 hkl ranges No.reflections measured; total, unique (Rint) Transmission factors No. observations [I>2.50s(I)] No. variables Reflection/parameter ratio Residual R, R9 Goodness of fit Maximum, minimum peaks in final difference map/e Å23 4 C46H41BF4N4O2P2Ru 931.68 Red, prism 0.48 × 0.20 × 0.20 22.314(5) 14.745(3) 26.887(6) 103.19(2) 8612(3) 1.437 3808.00 4.99 49.9 226 to 26, 0–17, 0–32 8046, 7906 (0.020) 0.91–0.92 5603 540 10.38 0.044, 0.041 2.12 0.55, 20.59 5 C46H42N4O4P2Ru 877.88 Colourless, prism 0.43 × 0.32 × 0.11 28.919(9) 20.550(5) 18.910(4) 119.57(2) 9774(4) 1.193 3616.00 35.51 120.5 0–32, 0–23, 221 to 18 7718, 7547 (0.032) 0.35–0.70 5760 527 10.93 0.053, 0.061 3.89 0.58, 20.86 * Details in common: monoclinic, space group C2/c (no. 15); Z = 8; 21 8C; function minimised Sw(|Fo| 2 |Fc|)2; w21 = 4Fo 2/s2(Fo); anomalous dispersion on all non-hydrogen atoms; maximum shift/error in final cycle 0.00.J. Chem.Soc., Dalton Trans., 1997, Pages 2341–2345 2343 The deviation from coplanarity of the components of the bidentate imidazole ligands of complexes 4 and 5, provides a minor extension of the limited bite of the ligand co-ordinated to the large ruthenium ion. The larger deviation from coplanarity evident in 4 is probably driven by contact between the carbonyl O(2) atom and the methyl C(4) and C(8) atoms.The distance between O(2) and C(4) is 2.801(8) Å, and that between O(2) and C(8) is 2.770(8) Å. The O(2) to C(4) and C(8) distances in 5 are 3.24(1) and 3.28(1) Å. There are several close contacts between the imidazolyl rings of the bidentate imidazole ligand and the triphenylphosphine ligands. For example in complex 4 the N(1) to C(12) distance is 3.299(5) Å, N(2) to C(40) is 3.044(5) Å, N(2) to C(24) is 3.193(5) Å, N(2) to C(35) is 3.195(5) Å and N(2) to C(23) is 3.269(5) Å.Similar contacts are found in the structure of 5. In complex 5 the OH2 counter ion is hydrogen bonded to the metal carbonyl ligand while the solvent of crystallisation (H2O) is hydrogen bonded to the OH group on the ligand backbone. The Ru]P bond lengths in complex 4 are almost identical at 2.357(1) and 2.356(1) Å, and very similar to those in 5 [2.336(2) and 2.385(2) Å]. Comparison with the other known ruthenium complexes containing polydentate nitrogen donor ligands, tridentate imidazole-based ligands,20 tris(pyrazol-1-yl)methane and tris(pyrazol-1-yl)borane complexes, reveals very similar Ru]P bond lengths ranging between 2.33 and 2.37 Å.22,23 The Ru]N bond lengths are almost identical in 4 and 5, at 2.176(3) and 2.135(3) in 4 and 2.181(5) and 2.139(5) Å in 5.In each complex that opposite the metal-bound hydride is longer [2.176(3) and 2.181(5) Å] than the one opposite the metal-bound carbonyl [2.135(3) and 2.139(5) Å].Again, other known complexes of tridentate imidazole ligands and tris(pyrazol- 1-yl)methane and tris(pyrazol-1-yl)borate complexes with Ru have very similar Ru]N bond lengths, ranging between 2.12 and 2.17 Å.22,23 NMR Assignment of complexes 1–3 The 1H, 31P and 13C NMR spectra were completely assigned for complexes 1–3, using two-dimensional methods. In each of the complexes, the two imidazolyl rings in the ligand are nonequivalent, with one (A) trans to the hydride ligand and the other (B) trans to the carbonyl ligand.The assignment of protons to the heterocyclic rings A or B was achieved using two-dimensional 1H nuclear Overhauser effect spectroscopy (NOESY). One imidazolyl ring (B) is directed towards the metal-bound hydride and a NOESY interaction between H4 B and the metal-bound hydride is observed, while the protons (H4 and H5) on the other imidazolyl ring (A) do not interact with the hydride ligand.The assignments of the resonances of the two methyl groups on nitrogen to their respective imidazolyl rings was also achieved using the 1H NOESY NMR spectrum; NOESY interactions were observed between each methyl group and the proton H5 on the same imidazolyl ring. For complexes 1 and 3 the two trans triphenylphosphine ligands appear as a singlet in the 31P-{1H} NMR spectrum. In the case of [Ru- (PPh3)2H(CO)L2]Cl 2 the two trans triphenylphosphine ligands are non-equivalent.The 31P-{1H} NMR resonances for 2 appear as two tented doublets with a large 2JPP coupling constant of 287 Hz, characteristic of the trans disposition of the phosphines. Although no crystal structure was obtained for [Ru(PPh3)2- H(CO)L3]Cl 3, the NMR data indicate that the structure is analogous to those of 1 and 2. In 3, the two triphenylphosphine ligands are mutually trans and equivalent, as in 1, and the two imidazolyl rings of the ligand were assigned to A and B positions using the 1H NOESY NMR spectrum. Conclusion Three new ruthenium(II) complexes containing bidentate imidazole-based ligands L1–L3 have been synthesized and characterised.Reaction of the appropriate bidentate L with [Ru- (PPh3)3H(Cl)(CO)] in toluene solvent led to the formation of [Ru(PPh3)2H(CO)L1]Cl 1, [Ru(PPh3)2H(CO)L2]Cl 2 and [Ru- (PPh3)2H(CO)L3]Cl 3, in good yields of between 65 and 88%. The complexes contain a single bidentate imidazole ligand, two triphenylphosphines, a hydride and a carbonyl.X-Ray analysis shows that they are essentially octahedral. Distortion from perfect octahedral symmetry is primarily due to steric effects of the triphenylphosphine ligands and the small bite angle of the bidentate imidazole ligands. Experimental All manipulations of metal complexes and air-sensitive reagents were carried out using standard Schlenk or vacuum techniques,24 or in a Vacuum Atmospheres argon-filled drybox.Ruthenium(III) trichloride hydrate was obtained from both Aldrich and Johnson Matthey, and used without further purifi- cation. n-Butyllithium was used as a solution in hexane (ª2.4 mol dm23) as supplied by Aldrich and was titrated immediately prior to use against 2,5-dimethoxybenzyl alcohol.25 N-Methylimidazole was obtained from Aldrich and used without further purification. Tetrahydrofuran and toluene were stored over sodium wire and distilled under nitrogen immediately prior to use from sodium–benzophenone ketyl.Light petroleum refers to the fraction with bp 60–80 8C. The mass spectra of organic compounds were recorded on a Kratos MS9/MS50 double-focusing mass spectrometer, those of organometallic complexes on a Finnigan MAT TSQ-46 mass spectrometer (San Jose, CA, USA). In the case of organometallic complexes in which the overall mass spectrum is predominantly that of the ligands, spectra were recorded by scanning mass ranges greater than that of the free L, typically m/z >250.Peaks with low intensity are not quoted unless deemed signifi- cant. Infrared spectra were recorded on a Perkin-Elmer 1600 series FTIR spectrophotometer. Melting points were determined using a Gallenkamp apparatus and are uncorrected. The 1H, 31P and 13C NMR spectra were recorded on Bruker AMX400 and AMX600 spectrometers at 300 and 303 K respectively. Chemical shifts are internally referenced to residual solvent in the case of 1H and 13C, and to external neat trimethyl phosphite (d 140.85) in the case of 31P spectra.Carbonylchlorohydridotris(triphenylphosphine)ruthenium(II) was prepared by the method of Ahmad et al.19 Crystallography A red prismatic crystal of complex 4 was attached to a thin glass fibre, and mounted on an Enraf-Nonius CAD4 diffractometer employing graphite-monochromated Mo-Ka radiation (l 0.710 93 Å). C-Centred monoclinic cell constants were obtained from a least-squares refinement using the setting angles of 25 machine-centred reflections in the range 19.6 < 2q < 24.28.Data were collected using w–q scans with a scan width of (1.50 1 1.05 tan q)8. The intensities of three representative reflections measured every 60 min decreased by 3.2%, and a linear correction was accordingly applied to the data. The crystal faces were indexed and an analytical absorption correction was applied to the data. A colourless prismatic crystal of complex 5 was attached to a thin glass fibre and mounted on a Rigaku AFC7R diffractometer employing graphite-monochromated Cu-Ka radiation (l 1.541 78 Å) from a 12 kW direct drive rotating-anode generator.C-Centred monoclinic cell constants were obtained from a least-squares refinement using the setting angles of 25 automatically centred reflections in the range 90.42 < 2q < 97.638. Omega scans of several intense reflections made prior to data collection had an average width at half-height of 0.248.Data were collected using w–2q scans with a scan width of (1.68 1 0.35 tan q)8. The intensities of three representative2344 J. Chem. Soc., Dalton Trans., 1997, Pages 2341–2345 reflections measured every 150 decreased by 3.3% during the data collection, and a linear correction was applied to the data. Other details as for 4. All calculations were performed using the TEXSAN26 crystallographic software package. The data were corrected for Lorentz-polarisation effects. The data obtained from both complexes 4 and 5 showed systematic absences of hkl (h 1 k � 2n) and h0l (l � 2n), and the structures were solved in the space group C2/c (no. 15). The structures were solved by direct methods27 and expanded using Fourier-difference maps.28 The non-hydrogen atoms were refined anisotropically, and the hydrides were refined isotropically. The remaining hydrogen atoms were included in the full-matrix least-squares refinements at calculated positions with group thermal parameters.The tetrafluoroborate anion of 4 proved to be disordered and was refined with eight fluorine sites of equal occupancy. After several cycles of refinement the positions of the fluorine atoms were fixed. The crystal structure for complex 5 was modelled as [Ru(PPh3)2H(CO)L2]OH?H2O, with no hydrogens attached to the oxygen atoms, and the water oxygen equally distributed between two lattice sites. The residual weighting scheme was based on counting statistics and included a statistical uncertainty factor (p = 0.001 for 4 and 0.003 for 5).Neutral atom scattering factors were taken from Cromer and Waber.29 Anomalous dispersion effects were included in the structure-factor calculation,30 and the values for Df 9 and Df 0 were those of Creagh and McAuley.31 The values for the massattenuation coefficients were those of Creagh and Hubbell.32 Atomic coordinates, thermal parameters, and bond lengths and angles have been deposited at the Cambridge Crystallographic Data Centre (CCDC).See Instructions for Authors, J. Chem. Soc., Dalton Trans., 1997, Issue 1. Any request to the CCDC for this material should quote the full literature citation and the reference number 186/495. Synthesis of bidentate imidazoles Bis(1-methylimidazol-2-yl) ketone L1. There have been several reports of the synthesis of compound L1,9,13,17 a modification of the method described by Lippard and co-workers.17 was used. n-Butyllithium (110 mmol) was added to a solution of 1- methylimidazole (10 cm3, 125 mmol) in tetrahydrofuran (thf ) (150 cm3) at 278 8C under nitrogen.The solution was stirred for 1 h at 278 8C after which time diethyl carbonate (6 cm3, 50 mmol) was added. The solution changed from pale yellow to purple and thickened. It was allowed to warm to 240 8C over several hours, quenched by addition of solid carbon dioxide and then allowed to warm to room temperature. Water (100 cm3) was added and the product obtained by continuous liquid– liquid extraction into ethyl acetate (600 cm3) for 10–12 h.The ethyl acetate solvent was removed and the residue recrystallised from acetone. The product L1 was obtained as a colourless crystalline solid (6.6 g, 63%), m.p. 154–155.5 8C (lit.,13 145–148 8C). dH(400 MHz, CDCl3) 7.31 (s, 1 H, H4), 7.09 (s, 1 H, H5) and 4.02 (s, 3 H, NCH3); dC-{H}(100 MHz, CDCl3) 174.4 (C]] O), 143.4 (C2), 130.7 (C4), 127.2 (C5) and 36.6 (NCH3); m/z 191 (11, [M 1 1]1), 190 (88, M1), 162 (19), 161 (70), 109 (100), 96 (22), 95 (32), 82 (60), 54 (30), 53 (10), 52 (11), 42 (17) and 40 (14%).High-resolution mass spectrum (M1): m/z 190.0845; C9H10N4O requires 190.0855. Bis(1-methylimidazol-2-yl)methanol L2. This compound was synthesized using a modification of the procedure described by Breslow and co-workers.4 n-Butyllithium (40 mmol) was added to 1-methylimidazole (6.6 cm3, 83 mmol) in thf (200 cm3) at 278 8C under nitrogen. The solution was stirred for 1.5 h after which time ethyl formate (3 cm3) was added.The solution was allowed to warm to 10–20 8C over several hours, quenched with water (100 cm3) followed by continuous liquid–liquid extraction into ethyl acetate (400 cm3) for 10–12 h. The ethyl acetate solvent was removed and the residue recrystallised from acetone to yield L2 as a white crystalline solid (2.7 g, 70%), m.p. 199– 202 8C (lit.,4 188–189.5 8C). dH(400 MHz, CDCl3) 6.90 [d, 2 H, 3J(H4H5) = 1.2 , H4], 6.82 [d, 2 H, 3J(H4H5) = 1.2 Hz, H5), 6.02 (s, 1 H, CHOH) and 3.59 (s, 6 H, NCH3); dC-{H}(100 MHz, CDCl3) 146.6 (C2), 127.4 (C4), 123.3 (C5), 65.1 (COH) and 33.9 (NCH3); m/z 193 (10, [M 1 1]1), 192 (51, M1), 191 (39), 175 (8), 163 (10), 111 (42), 109 (35), 96 (100), 95 (22), 83 (100), 82 (39), 81 (27), 56 (17), 55 (11), 54 (17), 52 (10), 42 (51) and 41 (10%).Bis(1-methylimidazol-2-yl)methane L3. This compound was prepared using a modification of the method described by Byers and Canty.13 The ketone L1 (3.50 g, 18 mmol) was placed in a glass-sleeved stainless-steel reaction bomb (600 cm3) with hydrazine hydrate 33 (10.0 cm3, 194 mmol) and sodium hydroxide (1.50 g, 37.5 mmol). The vessel was sealed and heated to 150 8C for 4 h after which it was cooled to room temperature and opened carefully.The product was extracted into acetone and the solvent removed under vacuum. Compound L3 was recrystallised from acetone as a cream solid (1.27 g, 39%), m.p 152–154 8C (lit.,7 143–148 8C). dH(400 MHz, CDCl3) 6.84 [d, 1 H, 3J(H4H5) = 1.2 , H4], 7.09 [d, 1 H, 3J(H4H5) = 1.2 Hz, H5], 4.16 (s, 1 H, CH2) and 3.59 (s, 3 H, NCH3); dC-{H}(400 MHz, CDCl3) 144.2 (C2), 127.9 (C4), 122.1 (C5), 33.8 (NCH3) and 27.5 (CH2); m/z 177 (10, [M 1 1]1), 176 (75), 175 (27), 161 (20), 134 (10), 107 (13), 96 (65), 95 (100), 81 (23), 55 (12), 54 (38), 53 (10) and 52 (14%).High-resolution mass spectrum (M1): m/z 176.1062; C9H12N4 requires 176.1062.Synthesis of ruthenium complexes [Ru(PPh3)2H(CO)L1]Cl 1. A mixture of [Ru(PPh3)3H(Cl)- (CO)] (0.61 g, 0.64 mmol) and L1 (0.16 g, 0.82 mmol) in toluene (40 cm3) was refluxed for 2 h. The orange solution was allowed to cool to room temperature and the yellow precipitate which formed was filtered off and washed with hexane (20 cm3). The crude product was recrystallised from methanol to give [Ru(PPh3) 2H(CO)L1]Cl 1 as orange plates (0.50 g, 88%), m.p. 107 8C (decomposed without melting).dH(600 MHz, CDCl3) 7.71 (s, 1 H, H5 A), 7.36–7.23 (m, 31 H, PPh3 and H4 A), 7.09 (s, 1 H, H5 B), 6.50 (s, 1 H, H4 B), 3.97 (s, 3 H, NCH3A), 3.84 (s, 3 H, NCH3B) and 211.63 [t, 1 H, 2J(H]Ru]P) = 18.7 Hz, RuH]; dC-{H, P}(100 MHz, CDCl3) 204.9 (RuCO), 166.7 (CO of L1), 140.0, 139.4 (C2 A,B), 136.6 (C4 B), 134.6 (C4 A), 133.8 (PPh3), 132.4 (PPh3), 131.0 (PPh3), 130.7 (C5 B), 129.5 (C5 A), 128.9 (PPh3) and 39.9 (NCH3A,B); dP(162 MHz, CDCl3) 47.11 (s); FAB mass spectrum m/z 847 (15, [M 1 2]1), 846 (13, [M 1 1]1), 845 (22, M1), 844 (19), 843 (13), 842 (14), 586 (12), 585 (33), 584 (35), 583 (100), 582 (35), 581 (89), 580 (60), 579 (38), 578 (34), 577 (12), 575 (13), 556 (11), 555 (19), 554 (19), 553 (23), 552 (17) and 551 (14%); n& max/cm21 (Nujol) 1929m (Ru]C]] ] O), stretch corresponding to Ru]H not observed.Crystals of the complex [Ru(PPh3)2H(CO)L1]BF4 4 suitable for structure analysis were obtained by addition of a methanol solution of NaBF4 to a methanol solution of 1 followed by slow evaporation of the solvent.[Ru(PPh3)2H(CO)L2]Cl 2. A mixture of [Ru(PPh3)3H(Cl)- (CO)] (0.36 g, 0.38 mmol) and L2 (0.13 g, 0.68 mmol) in toluene (40 cm3) was refluxed for 2 h. The clear solution was allowed to cool to room temperature, the solvent removed and the residue dissolved in acetone. Light petroleum was added causing the precipitation of a white solid which was filtered off. The crude product was recrystallised from methanol to give [Ru(PPh3)2- H(CO)L2]Cl 2 as colourless needles (0.22 g, 65%), m.p. 140 8C (decomposed without melting). dH(400 MHz, CDCl3) 7.42–7.11 (m, 30 H, PPh3), 6.69 (s, 1 H, H4 A), 6.59 (s, 1 H, H5 A), 5.95 (s, 1 H, H5 B), 5.83 (s, 1 H, H4 B), 5.31 (s, 1 H, CHOH), 3.74 (s, 3 H, NCH3A), 3.69 (s, 3 H, NCH3B) and 211.91 [dd, 1 H, 2J(H]Ru]P) = 17.4, 22.0 Hz, RuH]; dC-{H,P}(100 MHz, CDCl3)J. Chem. Soc., Dalton Trans., 1997, Pages 2341–2345 2345 205.7 (RuCO), 145.1, 144.7 (C2 A,B), 134.5 (PPh3), 134.0 (PPh3), 133.7 (C4 B), 133.4 (C4 A), 128.6 (PPh3), 128.4 (PPh3), 123.2 (C5 A), 122.2 (C5 B) 5(COH) and 36.3 (NCH3A,B); dP(162 Hz, CDCl3) 47.7 [d, 2J(P]Ru]P) = 287] and 44.3 [d, 2J(P]Ru]P) = 287 Hz]; FAB mass spectrum m/z 849 (12, [M 1 2]1), 848 (11, [M 1 1]1), 847 (32, M1), 845 (17), 587 (24), 586 (28), 585 (80), 584 (56), 583 (100), 582 (67), 581 (47), 580 (37), 579 (13), 577 (16), 569 (17), 568 (16), 567 (21), 566 (18), 565 (13), 564 (10), 557 (15), 556 (14), 555 (29), 554 (21), 553 (20), 552 (14), 540 (11), 539 (15), 538 (13), 537 (14) and 536 (11%); n& max/cm21 (Nujol) 2014w (Ru]H), 1927m (Ru]C]] ] O).Crystals of the complex [Ru(PPh3)2H(CO)L2]OH 5 suitable for structure analysis were obtained by slow evaporation of a methanol–water (99 : 1) solution of 2. [Ru(PPh3)2H(CO)L3]Cl 3. A mixture of [Ru(PPh3)3H(Cl)- (CO)] (0.50 g, 0.52 mmol) and L3 (0.12 g, 0.68 mmol) in toluene (30 cm3) was refluxed for 3 h during which time a precipitate formed.The mixture was cooled to room temperature and the precipitate filtered off and washed with hexane (10 cm3). Complex 3 was obtained as a white solid (0.39 g, 86%), m.p. 215 8C (decomposed without melting). dH(400 MHz, CDCl3) 7.38–7.25 (m, 30 H, PPh3), 6.66 [d, 1 H, 3J(H4 AH5 A) = 1.7, H5 A], 6.58 [d, 1 H, 3J(H4 AH5 A) = 1.7, H4 A], 6.12 [d, 1 H, 3J(H4 BH5 B) = 1.7, H4 B), 6.08 [d, 1 H, 3J(H4 BH5 B) = 1.7, H5 B], 3.83 (s, 3 H, NCH3A), 3.68 (s, 2 H, CH2), 3.66 (s, 3 H, NCH3B) and 211.82 [t, 1 H, 2J(H] Ru]P) = 19.5 Hz, RuH]; dC-{H,P}(100 MHz, CDCl3) 205.2 (RuCO), 142.1, 142.0 (C2 A,B), 134.2 (PPh3), 133.9 (PPh3), 133.6 (C4 B), 132.74 (C4 A), 130.5 (PPh3), 128.7 (PPh3), 122.6 (C5 A), 121.4 (C5 B), 35.9 (NCH3A,B) and 24.5 (CH2); dP(162 MHz, CDCl3) 45.1 (s); FAB mass spectrum m/z 831 (3, M1), 657 (14), 655 (25), 654 (14), 640 (25), 638 (15), 607 (16), 606 (27), 605 (70), 604 (49), 603 (100), 602 (69), 601 (49), 600 (39), 599 (14), 597 (15), 569 (22), 568 (16), 567 (30), 566 (24), 565 (14), 564 (12), 525 (28), 524 (30), 519 (15), 518 (44), 517 (34), 516 (77), 515 (51), 514 (43), 513 (31) and 512 (15%); n& max/cm21 (Nujol); 1919m (Ru]C]] ] O), stretch corresponding to Ru]H not observed (Found: C, 61.4; H, 5.4; N, 6.2.Calc. for C46H43ClN4OP2Ru? 2H2O: C, 61.23; H, 5.25; N, 6.21%). Acknowledgements We gratefully acknowledge financial support from the Australian Research Council and thank Johnson-Matthey Pty.Ltd. for a generous loan of ruthenium salts. References 1 A. Togni and C. M. Venanzi, Angew. Chem., Int. Ed. Engl., 1994, 33, 497 and refs. therein. 2 R. S. Brown, N. J. Curtis and J. Huguet, J. Am. Chem. Soc., 1981, 103, 6953. 3 See, for example, T. N. Sorrell and A. S. Borovik, J. Am. Chem. Soc., 1987, 109, 4255; R. S. Brown, D. Solmom, N. J. Curtis and S. Kusuma, J. Am. Chem. Soc., 1982, 104, 3188; F. Chu, J. Smith, V. M. Lynch and S. J. Lippard, Inorg.Chem., 1995, 34, 5689. 4 C. C. Tang, D. Davilian, P. Huang and R. Breslow, J. Am. Chem. Soc., 1978, 100, 3918. 5 R. Breslow, J. T. Hunt, R. Smiley and T. Tarnowski, J. Am. Chem. Soc., 1983, 105, 5337. 6 P. Frediani, M. Bianchi, A. Salvini, R. Guanducci, L. C. Carluccio and F. Piancenti, J. Organomet. Chem., 1995, 498, 187. 7 F. A. Jalón, A. Otero, A. Rodríguez and M. Pérez-Manrique, J. Organomet. Chem., 1996, 508, 69. 8 L. K. Thompson, B. S. Ramaswamy and E. A. Seymour, Can.J. Chem., 1977, 55, 878. 9 X.-M. Chen, Z.-T. Xu and T. C. W. Mak, Polyhedron, 1995, 14, 319. 10 W. B. Tolman, S. Liu, J. G. Bensten and S. J. Lippard, J. Am. Chem. Soc., 1991, 113, 152. 11 T. N. Sorrell, W. E. Allen and P. S. White, Inorg. Chem., 1995, 34, 952; N. Wei, N. N. Murthy, Z. Tyeklár and K. D. Karlin, Inorg. Chem., 1994, 33, 1177. 12 P. K. Byers, A. J. Canty and R. T. Honeyman, J. Organomet. Chem., 1990, 385, 417; P. K. Byers and A. J. Canty, J. Chem. Soc., Chem. Commun., 1988, 639; P.K. Byers, A. J. Canty, B. W. Skelton and A. H. White, Organometallics, 1990, 9, 826; G. B. Brown, P. K. Byers and A. J. Canty, Organometallics, 1990, 9, 1231. 13 P. K. Byers and A. J. Canty, Organometallics, 1990, 9, 210. 14 M. J. Bloemink, H. Engelking, S. Karentzopoulos, B. Krebs and J. Reedijk, Inorg. Chem., 1996, 35, 619. 15 A. J. Canty, P. R. Traill, B. W. Skelton and A. H. White, Inorg. Chim. Acta, 1996, in the press. 16 M. Grebl and B. Krebs, Inorg.Chem., 1994, 33, 3877. 17 S. M. Gorun, G. C. Papaefthmiou, R. B. Frankel and S. J. Lippard, J. Am. Chem. Soc., 1987, 109, 4244. 18 R. J. Brown and J. Huguet, Can. J. Chem., 1980, 58, 889. 19 N. Ahmad, J. J. Levison, S. D. Robinson and M. F. Uttley, Inorg. Synth., 1974, 15, 45. 20 S. Elgafi, B. A. Messerle, L. D. Field, I. E. Buys and T. W. Hambley, J. Organomet. Chem., in the press. 21 C. K. Johnson, ORTEP, Report ORNL-5138, Oak Ridge National Laboratory, Oak Ridge, TN, 1976. 22 L. P. Soler, B. A. Messerle, L. D. Field, I. E. Buys and T. W. Hambley, unpublished work. 23 N. W. Alcock, I. D. Burns, K. S. Claire and A. F. Hill, Inorg. Chem., 1992, 31, 2906. 24 D. F. Shriver and M. A. Drezdzon, The Manipulation of Air Sensitive Compounds, Wiley, New York, 1986. 25 M. R. Winkle, J. M. Lansinger and R. C. Ronald, J. Chem. Soc., Chem. Commun., 1980, 87. 26 TEXSAN, Crystal Structure Analysis Package, Molecular Structure Corporation, The Woodlands, TX, 1985 and 1992. 27 G. M. Sheldrick, SHELXS 86, Crystallographic Computing 3, eds. G. M. Sheldrick, C. Kruger and R. Goddard, Oxford University Press, 1985, pp. 175–189. 28 DIRDIF 94, P. T. Beurskens, G. Admiraal, G. Beurskens, W. P. Bosman, R. de Gelder, R. Israel and J. M. M. Smits, The DIRDIF 94 program system, Technical Report of the Crystallography Laboratory, University of Nijmegen, 1994. 29 D. T. Cromer and J. T. Waber, International Tables for X-Ray Crystallography, Kynoch Press, Birmingham, 1974, vol. 4, Table 2.2 A. 30 J. A. Ibers and W. C. Hamilton, Acta Crystallogr., 1964, 17, 781. 31 D. C. Creagh and W. J. McAuley, International Tables for Crystallography, ed. A. J. C. Wilson, Kluwer, Academic Publishers, Boston, 1992, vol. C, Table 4.2.6.8, pp. 219–222. 32 D. C. Creagh and J. H. Hubbell, International Tables for Crystallography, ed. A. J. C. Wilson, Kluwer, Academic Publishers, Boston, 1992, vol. C, Table 4.2.4.3, pp. 200–206. 33 Hazards in the Chemical Laboratory, ed. S. G. Luxon, 5th edn., The Royal Society of Chemistry, Cambridge, 1992, p. 419. Received 21st January 1997; Paper 7/00474E