J. Am. Chem. SOC.1992,114, 922-930
922
Transition-Metal Complexes with Sulfur Ligands. 82.' H2S, S2, and CS2 Molecules as Ligands in Sulfur-Rich [ Ru(PPh3)'S4'] Complexes ('S4'2-= 1,2-Bis[(2-mercaptophenyl)thio]ethane(2-)) Dieter Sellmann,* Peter Lecher, Fak Knoch, and Matthias Moll Contribution from the Institut fur Anorganische Chemie der Universitat Erlangen-Nurnberg, Egerlandstrasse 1 , 0-8520 Erlangen, Federal Republic of Germany. Received June 5, 1991 Abstract: Red [Ru(PPh3)'S,'], ('S,'2- = 1,2-bis[(2-mercaptophenyl)thio]ethane(2-)) reacts in liquid HzS at -70 OC to give [Ru(SHz)(PPh3)'S4'] (1) which recrystallizes from H2S-saturated THF as 1-THF in yellow-orange single crystals. Crystals of 1-THF are monoclinic, space group P21/c, with a = 1124.7 (9) pm, b = 1378.5 (14) pm, c = 2274.0 (16) pm, 6 = 97.06 (6)O, V = 3499 ( 5 ) X lo6 pm3, Z = 4, and R, (R) = 0.056 (0.065) for 3366 reflections. 1.THF is the first of the rare and often very unstable H2S complexes that could be characterized by X-ray crystallography and shows how H2S in complexes with sulfur-dominated coordination spheres is stabilized by hydrogen bonds. 1and 1-THFare rapidly oxidized by O2 to yield deep turquoise-blue [ ( ~ - S , ) ( R U ( P P ~ ~ ) ' S(2) ~ ' which ] ~ ] has a trans v ? ' - v ~ - bridge S~ and exists in two diastereomeric forms as proved by X-ray structure determination of 2.CH2C12and 2.CS2. Crystals of 2CH2CI2are triclinic, space group Pi,with a = 999.5 ( 5 ) pm, b = 1043.7 (7) pm, c = 1672.4 (14) pm, a = 78.89 (6)O, 6 = 89.46 ( S ) ' , y = 75.43 ( S ) " , V = 1655 (2) X lo6 pm3, and Z = 1. Due to unsatisfactory crystal quality, the structure could not be fully refined. Crystals of 2.CS2 are monoclinic, space group R 1 / c , with a = 2695.6 (10) pm, b = 1289.9 (4) pm, c = 1947.7 (6) pm, 6 = 105.66 (3)O, V = 6519 (4) X lo6 pm3, Z = 4, and R, ( R ) = 0.068 (0.079) for 7754 reflections. The RuSSRu core in 2 is a chromophore and is described as delocalized 4c-6e A system. A high degree of sulfur coordination at the Ru centers is assumed to be responsible for the unusual electronic properties of 2 compared with other p-S2 complexes. Addition of CS2 to [Ru(PPh3)'Sl] fragments leads to formation of binuclear deep red [(Ru(PPh3)](p-'S,'CS2){Ru(PPh3)'S,')](3; 'S4'CSZ2-= 2-[ [2-[(2-mercaptophenyl)thio]ethyl]thio]phenyltrithimrbonate(2-)) that exists in two diastereomericpairs of enantiomers. One pair was characterized by X-ray crystallography of SCS2that contains a bridging thioxanthate ligand in an unprecedented bonding mode. Crystals of 3.CS2 are monoclinic, space group Pi,with a = 1352.9 (6), b = 1414.9 (lo), c = 1848.4 (17) pm, a = 76.79 (6)O, 6 = 68.87 ( 5 ) O , y = 85.93 ( 5 ) O , V = 321 1 (4) X lo6 pm3, Z = 2, and R , (R) = 0.082 (0.104) for 3954 reflections.
Introduction
Experimental Section General Procedures. Unless noted otherwise, all reactions and operations were carried out under nitrogen with exclusion of light at room temperature by using standard Schlenk techniques. Solvents were dried and distilled before use. [Ru(PPh3)'S,'], was prepared as described in the literature." HIS was purchased in lecture bottles from Gerling, Holz & Co., Hanau, Germany. Spectra were recorded on the following instruments: IR, Zeiss IMR 25 and Perkin-Elmer 983; NMR, JEOL JNM-GX 270 and JNM-EX 270; UV-vis-near-IR, Shimadzu UV-3101 PC; Mass spectra, Varian MAT 212. Magnetic moments of solids were determined on a Johnson Matthey magnetic susceptibility balance at room temperature.
The interaction of H2S, HS-, and S2- with transition metals is widespread in nature and responsible for the formation of ores as well as [M>J clusters in active centers of redox enzymes like ferredoxines or nitrogenases. Hence, transition-metal complexes with such sulfur ligands are of great interest with regard to model compounds for these metal enzymes2 In contrast to the numerous and often very stable complexes with S2- ligands, complexes with ligands containing SH functions could be isolated only are rare and labile.3q4a H2S in exceptional cases. They were never studied by X-ray crystallography and differ in this respect remarkably from the ho(1) Part 81: Sellmann, D.; Geck, M.; Moll, M. Z. Naturforsch., in press. (2) Sellmann, D.; Barth, I. Inorg. Chim. Acta 1989,164, 171 and literature mologous H 2 0 complexes. Reasons might be the great reactivity reported therein. of H2Sand HS- ligands leading to fast consecutive reactions as (3) (a) Miiller, A,; Jagermann, W. Inorg. Chem. 1979, 18, 2631. (b) well as the high tendency of formation of sulfide-bridged strucMiiller, A.; Diemann, E. In Comprehensive Coordination Chemistry; Wilture~.~,~~ kinson, G., Gillard, R. D., McCleverty, J. A., Eds.; Pergamon Press: Oxford, Sz units are potential oxidation products of H2S ligands. S2 1987; Vol. 2, p 531. (4) (a) [R~(NHI)s(SH~)I(BF~)~ and [Ru(isn)(NH3),(SH2)I(BF4),(isn = molecules in the free state are unstable, but S2ligands have been isonicotmamide): Kuehn, C. G.; Taube, H. J . Am. Chem. Sot. 1976,98,689. proved in a number of complexes. Bridging of metal centers by (b) [M(CO)s(SH,)] (M = W, Cr): Herberhold, M.; Siiss, G. Angew. Chem. trans ~~-77I-s~ units is relatively rare3 and could be characterized 1976, 88, 375; Angew. Chem., Int. Ed. Engl. 1976, 15, 366. (c) [Mnby X-ray crystallography only in [(p-S2){Ru(NH3)5J2]C14.2H20,5 (CO),(PPh3)(SH,)]BF4: Harris, P. J.; Knox, S.A. R.; McKinney, R. J.; Stone, F. G. A. J. Chem. SOC.,Dalton Trans. 1978, 1009. (d) [CpMo[(r-s2)IMn(CP)(Co)2J21 [(~-Sz),IRu(MeCP)(PPh3))21 ,7 and (CO)3(SH2)]BF4and [CpW(CO),(SH2)]AsF6: Urban, G.; Siinkel, K.; Beck, [ ( ~ - S , ) ( R U ( C ~ ) ( P M(BF4)2,* ~ ~ ) ~ ] ~which ] exhibit metal centers W. J . Orgunomet. Chem. 1985, 290, 329. (e) [Re(CO)s(SH2)]BF4:Raab, with abiological coordination spheres. K.; Beck, W. Chem. Ber. 1985, 118, 3830. (f) [Pt(PPh3)2(SH2)]:Morelli, Heterocumulene CS2 is also highly reactive. Its chemistry in D.; Segre, A.; Ugo,R.; La Monica, G.; Genini, S.; Conti, F.; Bonati, E.J . Chem. Soc., Chem. Commun. 1967, 524. (9) [CpRu(PPh3),(SH2)]the coordination spheres of transition-metal complexes is currently (OS02CF3):Amarasekera, J.; Rauchfuss, T. B. Inorg. Chem. 1989,28,3875. intensively investigated. Coordination, insertion, addition, and ( 5 ) (a) Brulet, C. R.; Isied, S . S.; Taube, H. J . Am. Chem. Soc. 1973,95, cleavage reactions of CS2 are of interest, also with respect to 4758. (b) Elder, R. C.; Trkula, M. Inorg. Chem. 1977, 16, 1048. (c) Kim, S.; Otterbein, E. S.; Rava, R. P.; Isied, S.S.;San Filippo, J., Jr.; Waszcyak, reactions of the structurally closely related C02.9 J. V. J. Am. Chem. SOC.1983, 105, 336. In this work we report syntheses, structures, and reactions of (6) Herberhold, M.; Reiner, D.; Zimmer-Gasser, B.; Schubert, U. 2. [Ru(SH2)(PPh3)'Sl] (1) and [(p-S2)(Ru(PPh3)'s4'),1 (2) ('S4'2Naturforsch. 1980, 356, 1281. = 1,2-bis[(2-mercaptophenyl)thio]ethane(2-)) and [(Ru(7) Amarasekera, J.; Rauchfuss, T. B. Inorg. Chem. 1987, 26, 2017. (PP~~)](~L-'S~(CSJ(RU(PP~~)'S~')] (3) ('S4'CS22- = 2-[ [2-[(2(8) Amarasekera, J.; Rauchfuss, T. B.; Wilson, S. R. Inorg. Chem. 1987, 26, 3328. mercaptophenyl) thiolethyl] thio] phenyl trithiocarbonate(2-)) . (9) C r q , V.;Daran, J.-C.; Jeannin, Y.; Eber, B.; Huttner, G. OrgunoPreliminary results were reported elsewhere.2.'0 metallics 1991, 10, 448. (10) Sellmann, D.; Lechner, P.; Knoch, F.; Moll, M. Angew. Chem. 1991, 16
To whom correspondence should be addressed.
103, 599; Angew. Chem., Int. Ed. Engl. 1991, 30, 552. (11) Sellmann, D.; Barth, I.; Moll, M. Inorg. Chem. 1990, 29, 176.
0002-7863/92/1514-922$03.00/0 0 1992 American Chemical Society
J. Am. Chem. SOC.,Vol. 114, No. 3, 1992 923
Transition- Metal Complexes with Sulfur Ligands
Table I. Selected Crystallographic Data for [Ru(SH2)(PPh3)'S,'].THF (I-THF), [(r-S2)(Ru(PPh3)'S'J21.CH2Cl2 (2.CH2C12),
[(p-S2)(Ru(PPh3)'Si)2].CS2 (2.CS2), and, [(Ru(PPh,))(r-'S,'CS2)(Ru(PPh3)'S~]].CS2 (3.CS2) "pd
formula mol wt cryst dimens, mm space gP cell dimens a, pm b, pm c, pm a,deg 6, deg 7 9 deg V, pm3
z
dab g/c"
wavelength, pm measd temp, K measd reflns unique reflns obsd reflns u criterion no. parameters R/Rw
[Ru(SH2)(PPhd'S,'l. THF (1.THF) C36H370PRUS5
I(~C-S~)IRU(PP~S)'S,'I~I. [(r-s,)(Ru(PPh,)'s')2. CH2C12 (tCH2CI2) cs2 (2.CS2) C65C12H56P2RU2S10 C65H54P2RU2S12
778.08 0.40 X 0.20 X 0.20 P2dC
1491.68 0.15 X 0.15 X 0.05 Pi
1484.03 0.30 X 0.20 P2I/C
1124.7 (9) 1378.5 (14) 2274.0 (16) 90.00 (0) 97.06 (6) 90.00 (0) 3499 (5) x 106 4 1.48 7 1.073 200 7662 6662 4759 F > 60(F) 401 0.065/0.056
999.5 (5) 1043.7 (7) 1672.4 (14) 78.89 (6) 89.46 (5) 75.43 (5) 1655 (2) X lo6 1 1.49 7 1 .a73 200 6939 6727 2227 F > 64F) 204 0.151/0.151
2695.6 (10) 1289.9 (4) 1947.7 (6) 90.00 (0) 105.66 (3) 90.00 (0) 6519 (4) X lo6 4 1.51 71.073 200 13449 12457 7754 F > 6a(F) 716 0.079/0.068
Preparation of Compounds. [Ru(SH,)(PPh,)'S'].THF (1eTHF)from [Ru(PPh3)'S,'L. All procedures were carried out in a H2S atmosphere
with strict exclusion of O2 and H 2 0 by using H2S-saturated solvents! A IO-mL portion of H2S was condensed onto [Ru(PPh,)'S,'], (830 mg, 1.24 mmol) at -196 "C in a Schlenk tube. Slow warming of the mixture to -70 "C gave a red suspension, which rapidly turned into a clear yellow solution. Concentration of volume to 1 mL at -60 OC caused precipitation of yellow 1. Careful dissolution in 30 mL of cold (-50 "C) THF and slow addition of 30 mL of pentane (-10 "C) under rapid stirring yielded microcrystalline 1.THF which was separated, washed with pentane/THF (lO:l), and dried in a stream of H2S gas for 10 h. Yield: 745 mg (77%). Anal. Calcd for C36H370PR~S5 (778.08): c , 55.57; H, 4.79; S,20.61. Found: C, 55.88; H, 4.79; S,20.45. [(~-S,)(RU(PP~,)'S~}~~CH~C~~ (2.CH2C12)from 1. A IO-mL portion of H2S was condensed onto [Ru(PPh3)'S4'], (955 mg, 1.42 mmol) at -196 "C in a Schlenk tube. The mixture was slowly warmed to -70 OC and stirred until the red suspension had turned into a yellow solution. Its volume was reduced to 1 mL by evaporation of H2Sat -60 OC, and the resulting yellow residue was cautiously dissolved by addition of 40 mL of CH2C12. A gentle stream of air was bubbled through the solution, whereupon its color rapidly turned to turquoise-green. While the mixture was stirred at room temperature for 10 h, a dark blue suspension formed, the volume of which was reduced to half. The microcrystalline product was filtered off, washed with 10 mL of CH2C12,and recrystallized from CH2CI2/MeOH. Yield: 760 mg (72%). Anal. Calcd for C65C12H56P2Ru2SI0(1491.68): C, 52.34; H, 3.78; S, 21.50. Found: C, 52.61; H, 3.82; S, 21.40. 2.CS2 from [Ru(PPh,)'S,'L. To a solution of [Ru(PPh3)'S4'], (560 mg, 0.82 mmol) in 20 mL of CS2was added elemental sulfur (105 mg, 0.41 mmol). The color of the solution rapidly turned from red to dark green, and microcrystalline black-blue 2.CS2 precipitated. After the mixture was stirred for another 10 h, 2.CS2 was separated, washed with 30 mL of CS2, and dried in vacuum for 1 day. Yield: 540 mg (89%). Anal. Calcd for C65H54P2R~2S12 (1484.03): C, 52.61; H, 3.67. Found: C, 52.30; H, 3.58. [(Ru(PPh,)~(p-'S,'CS2)(Ru(PPh,)'S4()].CS2 (343,) from [Ru(PPh3)S;L From a clear red solution of [Ru(PPh,)'S,'], (520 mg, 0.77 mmol) in 25 mL of CS2,deep red 3CS2precipitated within 3 h. It was filtered off, washed with 15 mL of CS2, and dried in vacuum for 1 day. Yield: 510 mg (88%). Anal. Calcd for C66H54P2R~2S12 (1496.04): C, 52.30; H, 3.58; S,25.72. Found: C, 51.88; H, 3.61; S, 24.95. X-ray Structure Determinations. Yellow-orange cubes of 1-THFwere obtained from a saturated solution of freshly synthesized 1 in H2S-saturated THF that was layered with the same volume of H2S-saturated pentane for 3 days at 0 "C. Single crystals of 2.CH2CI2could so far be obtained only when saturated solutions of 2 were layered with MeOH at -60 OC and subsequently slowly warmed to room temperature. After 2-3 weeks the turquoise-blue solutions and also the precipitated crystals started decomposing under decolorization. Accordingly, the single crystals that could be obtained were small and of poor quality, and the crystallographic data allowed solution of the structure of 2.CH2Cl2but not a satisfactory refinement.
X
0.10
[IR~(~~~J))(~-'~~'CS~)IRU(PP~,)'S,')~.
cs2 (3.Cs2)
C66H54P2RU2S12
1496.04 0.30 X 0.20 Pi
X
0.05
1352.9 (6) 1414.9 (10) 1848.4 (17) 76.79 (6) 68.87 (5) 85.93 (5) 3211 (4) X lo6 2 1.55 71.073 200 9241 9033 3954 F>6 4 9 725 0.104/0.082
In the presence of air, very slow evaporation of deep red solutions of [Ru(PPh3)'S,'], in CS2 yielded black cubes of 2.CS2. Deep red single crystals of 3CS2were obtained from CS2solutions of [Ru(PPh3)'S,'], that were stored in Schlenk tubes closed by rubber stoppers. In the course of ca. 14 days, the solvent evaporated through the rubber stoppers and the remaining crystals were separated and washed with ether/ CHIC12 (311). The single crystals of 1-THF, 2.CH2Cl2,2-CS2,and 3CS2were sealed under N2 in glass capillaries. The structures were solved by direct methods (SHELXTL PLUS).Only in the case of 2.CH2Cl2were the carbon atoms refined isotropically; in all other cases, non-hydrogen atoms were refined anisotropically. The aromatic hydrogen atoms were calculated for ideal geometry and restricted during refinement; the methyl hydrogen atoms were calculated for ideal tetrahedra and rotated around their central carbon atom during refinement; the isotropic hydrogen atoms were refined with common temperature factors. The H2S hydrogen atoms of &THF were located by difference Fourier synthesis and fixed during refinement. Due to inferior refinement, hydrogen atom of 3CS2 were not calculated. Table I summarizes crystallographic data of the complexes. Results
Synthesis and Characterizationof [Ru(SHz)(PPh3)'S4'] (l), [(~-s~)(Ru(PPb,)'S4')21 (3,and [ ( R ~ ( P P ~ , ) ) ( ~ - ' S ~ ' C S Z ) ( R ~ (PPh,)'S;)] (3). Red [Ru(PPh3)'S4)Ix1'formally contains a five-coordinate Ru center and reacts with thioethers or disulfides, e.g., SPhz, SPhMe, SMez," and CH3SSCH3,lZin MeOH suspensions a t room temperature (eq 1).
L = monodentate sulfur ligand The analogous HIS complex, [Ru(SHz)(PPh3)'S~] (l),could not be obtained under these conditions. According to eq 2 only a mixture of [(p-Sz)(Ru(PPh3)'S4')z](2)2and other noncharacterized compounds formed.
+
[(~-S,){RU(PP~,)'S,')~]other compounds (2) L
The synthesis of 1 finally succeeded in liquid HIS at -70 OC according to eq 3.
(12) Sellmann,D.; Lechner, P.; Moll, M. 2.Naturforsch.1991,46b, 1459.
924 J. Am. Chem. SOC.,Vol. I 1 4, No. 3, 1992
Sellmann et al.
Table 11. Selected Spectroscopic Data for [Ru(SH,)(PPh,)'S,'].THF (IeTHF), [(cl-S2)(Ru(PPh3)'S,')2] (Z),and [lRu(pphj))(cl-'s,'Cs,)lRu(PPh,)'S,')l (3) IR (KBr): UV-vis-near-IR:b FD-MS: NMR:" 6, ppm compound v, cm+ A, nm (e, io-' L mol-' cm-I) m/e 2410 v(S-H...O) 'H 7.67-6.40 (23 H, m, CnHd,PPh$ 706 2.85-2.35 (4 H, m, c2H,j 1.96 (2 . H,. s,. SH) 42.2c 41.0d 8.00-6.30 (23 H, m, C6H4. PPhj)d 708 2.32-1.59 (4 H, m, C2H4) 41.0d 7.64-6.63 (46 H, m, C6H4, PPh$ 645 (O.9).si 1408 3.97-2.14 (8 H, m, C2H4) 1049 (13.7) 3 4.0'3'" 34.4'"/32. 1 d.' 7.87-6.43 (46 H, m, C6H4, PPhj)' 510 (13.6). 3.18-1.40 (8 H, m, C2H4) 38.513 1.2sd 38.7133.4 38.5/30.8c*k 39,3133.7 "270 MHz. bSolutions 1 X lo4 M. CInCD2C12/THF-d8 (1:2). C6D6. 'In CD2C12. 'In CS2/CD2C12(3:l). EIn CS2. *Resonance Raman spectrum at h = 647.1 nm. 'Identical for both diastereomers. 'From reaction solution. 'From the isolated substance. 'Noncentrosymmetric RR/SS ,
pair of enantiomers.
'"
Centrosymmetric RS isomer.
Under an atmosphere of HIS, 1 precipitates in yellow-orange crystals as 1.THF on recrystallization from H2S-saturated THF. In contrast to the highly labile solvent-free 1,the solvated 1.THF is stable at 25 O C , loses H2Sslowly in vacuum only, and can be ionized in the mass spectrometer without decomposition. 1 shows one single broad u(SH) at 2300 cm-l (KBr), whereas 1.THF exhibits two u(SH) at 2410 and 2290 cm-I. 'H N M R spectroscopicevidence for S H protons in 1is obtained only with solutions of freshly prepared 1 in H2S-containing mixtures of CD2C12/THF-ds (1:2). They exhibit the signal of free H2S (6 = 1.00 ppm) and, in addition, the slightly broadened signal for the protons of the HIS ligand at 6 = 1.96 ppm. The 'H N M R spectrum of the corresponding D2S complex [Ru(SD2)(PPh3)'S4'] does not show such a re~0nance.l~When the sample is slowly oxidized by air, the signal for the H2S ligand decreases and simultaneously splits into two signals, until it finally disappears. The splitting may be traced to the intermediate formation of two diastereomers of the p-S2H2 complex [(MS2H2)(R~(PPh3)'S4'}2] that, however, could not be isolated or further characterized. The final product is always turquoise-blue [(fi-S2)(Ru(PPh3)'S,'}2] (2) (eq 4). 2 is also obtained when both 1 and 1.THF are oxidized in the solid state by 02. +02
~ [ R ~ ( S H Z ) ( P P ~ ~-2H,O ) ' S ~ ' ] [(ML-~z)~RU(Pph3)'~4,),1(4) 1 2 We recently reported syntheses for 2 using s8 and NBu4SH as the sources of S2 unit$ oxidation of 1 is another possibility to obtain 2, whose formation is easily observed due to its characteristic color. 2 was further identified by 3'P(1H]N M R spectra. Two signals at 34.4 and 32.1 ppm (c6D6) in the spectra of 2, formed according to eq 4, showed that 2 can exist in two diastereomeric forms (see below). Also CS2 can act as source of S2units. We observed this when we attempted to obtain single crystals of the so far only unsatisfactorily characterized [Ru(PPh3)'S,'], by recrystallizing it from CS2. Single crystals of [Ru(PPh3)'S4'Ix were not obtained, but in the presence of air slow evaporation of the solvent yielded black crystals of 2.CS2 (eq 5). [Ru(PPh3)'S4'],
CSdOl
2.CS2
+ other products
(5)
It remains uncertain so far whether 2 is formed by direct addition of sulfur originating from oxidation of CS2or by oxidation (13) The D2S required for the synthesis of [Ru(SD,)(PPh,)'S,']
was pre-
pared from Na2S and D2SO4 (50% in D20), condensed into a Schlenk tube at -78
OC,
and dried over 4-A molecular sieves.
of the binuclear thioxanthate complex [(Ru(PPh3))(p'S4'CS2)IRu(PPh3"'JI (3). Dissolution of [Ru(PPh,)'S,'], in CS2 yields deep red solutions. They do not contain [Ru(PPhs)'S,'],, but deep red 3 (kx = 510 nm) formed according to eq 6 by addition of CS2to mononuclear [Ru(PPh3)'Si] fragments. 2[RU(PPhd(S4)1 + c%
Cs, 7
Ld' 3
It is to be expected that formation of 3 from racemic [Ru(PPh3)'S4'] fragments leads to two diastereomeric pairs of enantiomers (seebelow). They give rise to four signals in the 31P(1H) N M R spectrum of the reaction solution (Figure 1) that exhibit approximately pairwise equal intensities. One pair of enantiomers of 3 could be isolated from these solutions as 3CS2 and characterized by X-ray crystallography. The addition of CS2 to [Ru(PPh3)'Si] fragments according to eq 6 is likely reversible because addition of elemental sulfur to the CS2solutions leads again to rapid formation of the p-S2 complex 2 (eq 7).
Table I1 is a listing of selected spectroscopic data of 1-3. X-rayStructure Determinations. The molecular structures of 1.THF (Figure 2a), 2CH2CI2(Figure 3a), 2 C S 2 (Figure 3b), and 3CS2(Figure 4) were determined by X-ray crystallography. 2.CH2C12 and 2-CS2contain diastereomeric forms of 2. For this reason, the structure of 2CH2C12will be included although its refinement stopped at an unsatisfactory R = 0.15 1, not allowing discussion of bond distances and angles. Table I11 lists selected distances and angles of the complexes. In all complexes the R u atoms are found in sulfur-dominated coordination spheres. The R u centers are pseudooctahedrally coordinated by one phosphorus and five sulfur donors; angles as well as Ru-S and Ru-P distances within the coordination polyhedra show no anomalies. In the unit cell of l.THF, enantiomers of 1 are associated via two S-H-S bridges to give a cyclic centrosymmetric dimer. In addition, a THF molecule is bound to each H2S ligand via one S-H-0 bridge (Figure 2b).
Transition- Metal Complexes with Sulfur Ligands
Isomer 1
J . Am. Chem. SOC.,Vol. 114, No. 3, 1992 925 Table 111. Selected Interatomic Distances (pm) and Angles (deg) for 1-THF, 2.CS2, and 3CS2 [Ru(SH2) (PPh,)'S,'].THF (1.THF) 239.7 ( 5 ) S(5)-H(5A)
Ru(1)-S(1) Ru(l)-S(2) Ru(l)-S(3) Ru(l)-S(4) Ru(l)-S(5) Ru(l)-P(l) S(l)-Ru(l)-S(2) S(l)-Ru(l)-S(3) S(l)-Ru(l)-S(4) S(l)-Ru(l)-S(S) S(2)-Ru(l)-S(3) S(2)-Ru(l)-S(4) S(2)-Ru(l)-S(5) S(3)-Ru(l)-S(4) S(3)-Ru(l)-S(5) S(4)-Ru(l)-S(5)
r
AJ
Figure 1. 31P(lH)NMR spectrum of the deep red solution of 3 in CS2.
The S-H-8 bridges in 1.THF (Figure 5 ) form angles of 153'; the sum of the distances S(5)-H(5A) and H(5A).-S(4A) is 378 pm and the distance S(5)-.S(4A) is 369 pm. The S-H--0 bridges possess angles of 159', and the S--O distance is 333 pm. The very short S-S and S--O distances indicate that these hydrogen bridges must be strong. The Ru(1)-S(3) distance (229.3 (5) pm) in 1.THF in trans position to the HzS ligand is distinctly shorter than the other Ru-S distances (236.1 (5)-239.7 ( 5 ) pm); comparison with related [Ru(L)(PPh,)'S,'] complexes14suggests that this effect is due to a strong Ru+S(thioether) ?r-acceptor bond. The structure of 2.CHZClz (Figure 3b) could be solved but, as mentioned above, not satisfactorily refined. In 2-CH2Cl2,two enantiochiral [Ru(PPh3)'S4)] fragments are centrosymmetrically bridged via the ~ l - 7 l - S ligand; ~ the inversion center is located in the middle of the p-Sz unit. The RuSSRu core forms a plane toward which the [Ru(PPh3)'S4'] fragments are slightly twisted such that the Ru-P bonds form an angle of 47' with the RuSSRu plane. Both [Ru(PPh3)'S4'] fragments are eclipsed; the Ru-P bonds lie in a plane and stand in trans position with regard to the RuSSRu plane. The structure of 2 C S Zcould be fully refined (Figure 3b). In 2.CSz, the 7 1 ~ 1 - Sligand z bridges two [Ru(PPh3)'S4'] fragments that are formally homochiral; distances and angles in both fragments, however, are slightly different. Accordingly, the whole molecule has CIsymmetry only. The [Ru(PPh3)'S,'] fragments are somewhat gauche configurated; the Ru-P bonds include an angle of 23' and accept cisoid positions with regard to the RuSSRu plane. The RuSSRu core has again trans configuration; it is, however, not exactly planar, and the Ru( 1)-S(5) and Ru(2)-S(10) bonds form a dihedral angle of 5.1'. The S-S distance of 199.1 (4) pmI5 is relatively short and lies between the values of free S2(188.7 ~ m ) and ~ " H2S2(205.5 pm)I6 such that partial double-bond character for the p-S2 unit is indicated. Other $3, complexes usually show longer S-S distances between 201 and 205 ~ m and , a~ shorter S-S distance than in ~~)~]~] 2-CSz has been found only in [ ( ~ - S , ) ( R U ( C ~ ) ( P M(BF4)2 (14) Sellmann, D.; Barth, I.; Knoch, F.;Moll, M.Inorg. Chem. 1990, 29, 1822 and literature reported therein. (1 5) The S-S distances of the RS and SR isomers of 2 in 2-CH2C12also lie in this area. But owing to the insufficient refinement of crystallographic data, exact statements about the S-S distances cannot be made. (16) Winnewisser, G.; Winnewisser, H.; Gordy, W. J . Chem. Phys. 1968, 49, 3465.
Ru(l)-S(l) Ru(l)-S(2) Ru(l)-S(3) Ru(l)-S(4) Ru(l)-S(5) Ru(l)-P(l) S(5)-S(l0)
236.1 (5) 229.3 ( 5 ) 239.3 (5) 239.9 (5) 232.4 ( 5 ) 86.2 (1) 88.0 (1) 171.3 (1) 87.4 (1) 88.2 (1) 86.8 (1) 87.9 (1) 86.6 (1) 174.1 (1) 97.6 (1)
S(5)-H(5B) H(5A).-.S(4A) H(SB)..*O(l) S(5)..*S(4A) S(l)-RU(l)-P(l) S(Z)-Ru(l)-P(l) S(3)-Ru(l)-P(l) S(4)-Ru(l)-P(l) S(S)-Ru(l)-P(l) Ru(l)-S(S)-H(SA) Ru(l)-S(S)-H(SB) H(5A)-S(5)-H(5B) S(5)-H(5A)-S(4A) Ru(l)-S(4)-H(SAA) S(S)-H(5B)-0(1)
119 121 258 216 369 97.7 (1) 174.8 (1) 95.4 (1) 89.6 (1) 88.9 (1) 102 121 77 153 129 159
[(P-S~)IR~(PP~~)'S,')~~.CSI (2.CS2)
S(l)-Ru(l)-S(2) S(l)-Ru(l)-S(3) S(l)-Ru(l)-S(4) S(l)-Ru(l)-S(S) S(2)-Ru(l)-S(3) S(2)-Ru(l)-S(4) S(2)-Ru(l)-S(5) S(3)-Ru(l)-S(4) S(3)-Ru(l)-S(5) S(4)-Ru(l)-S(5) S(l)-Ru(l)-P(l) S(2)-Ru(l)-P(l) S(3)-Ru(l)-P(l) S(4)-Ru(l)-P(l) S(S)-Ru(l)-P(l) Ru(l)-S(S)-S(lO)
235.7 (3) 236.5 (3) 239.1 (3) 242.1 (3) 224.5 (3) 234.1 (3) 199.1 (4)
86.9 (1) 87.5 (1) 169.3 (1) 93.0 (1) 86.9 (1) 86.2 (1) 92.2 (1) 84.0 (1) 179.0 (1) 95.4 (1) 93.8 (1) 179.4 (1) 93.0 (1) 93.2 (1) 87.9 (1) 110.3 (1)
Ru(2)-S(6) 236.0 (3) Ru(2)-S(7) 236.2 (3) Ru(Z)-S(8) 239.8 (3) Ru(2)-S(9) 242.0 (3) Ru(2)-S(lO) 224.2 (3) Ru(2)-P(2) 235.2 (3) S(4)*-*S(12) 355 S(5).**S(ll) 385 S ( ~ ) - R U ( ~ ) - S ( ~ ) 87.1 (1) S(6)-Ru(2)-S(8) 86.6 (1) S ( ~ ) - R U ( ~ ) - S ( ~ )170.1 (1) S(6)-Ru(2)-S(lO) 95.7 (1) S(7)-Ru(Z)-S(8) 86.4 (1) S(7)-Ru(Z)-S(9) 87.0 (1) S(7)-Ru(Z)-S(lO) 91.9 (1) S(8)-Ru(Z)-S(9) 85.1 (1) S(8)-R~(2)-S(10) 177.0 (1) S(9)-R~(2)-S(10) 92.3 (1) S ( ~ ) - R U ( ~ ) - P ( ~ ) 92.7 (1) S ( ~ ) - R U ( ~ ) - P ( ~ )178.7 (1) S ( ~ ) - R U ( ~ ) - P ( ~ ) 92.3 (1) S ( ~ ) - R U ( ~ ) - P ( ~ )93.0 (1) S(lO)-Ru(2)-P(2) 89.4 (1) Ru(2)-S(lO)-S(5) 111.4 (1)
[(Ru(PP~~)J(~.'S,'CS~)(RU(PP~~)'S~')].CS~ (3.CS2) Ru( 1)-S( 1) Ru(l)-S(2) ~u(ij-s(3j Ru(l)-S(4) Ru(l)-S(5) Ru(1)-P(1) C(l)-S(5) S(l)-Ru( 1)-S(2) S( 1)-Ru( 1)-S( 3) S( l)-Ru( 1)-S(4) S( l)-Ru( 1)-S(5) S(2)-Ru( 1)-S(3) S(2)-Ru( 1)-S(4) S(2)-Ru( 1)-S(5) S(3)-Ru( 1)-S(4) S(3)-Ru( 1)-S(5) S(4)-Ru( 1)-S(5) S( 1)-Ru(l)-P(l) S(2)-Ru( 1)-P(l) S(3)-Ru( 1)-P( 1) S(4)-Ru( 1)-P(l) S(S)-Ru( 1)-P( 1) Ru(l)-S(S)C( 1) S(5)*(1)-S(9) S(5)-C( 1)-S( 10) S(9)-C(l)-S(lO)
239.6 (8) 232.7 (8) 236.0 (6j 240.0 (7) 236.3 (9) 234.2 ( 6 ) 159.3 (30) 87.4 (3) 85.8 (2) 169.4 (3) 105.4 (3) 87.8 (3) 84.9 (3) 164.9 (3) 86.8 (2) 85.1 (3) 81.4 (3) 92.4 (2) 90.7 (3) 177.7 (3) 94.9 (2) 96.6 (3) 123.9 (10) 114.9 (13) 141.8 (17) 103.1 (15)
R~l2)-S(6) - 23912 (8) Ru(2)-S(7) 230.0 (9) Ru(2)-S(8) 240.0 (7) Ru(2)-S(9) 235.0 (9) Ru(2)-S(lO) 244.6 (9) Ru(2)-P(2) 234.1 (8) C(l)-S(9) 189.1 (28) C(1)-S(l0) 173.4 (26) S ( ~ ) - R U ( ~ ) - S ( ~ ) 86.4 (3) S(6)-Ru(2)-S(8) 84.9 (3) S(6)-Ru(2)-S(9) 170.0 (3) S(6)-Ru(2)-S(lO) 102.1 (3) S ( ~ ) - R U ( ~ ) - S ( ~ ) 88.0 (3) S ( ~ ) - R U ( ~ ) - S ( ~ ) 98.5 (3) S(7)-Ru(2)-S(lO) 170.9 (3) S(8)-Ru(2)-S(9) 86.5 (3) S(8)-R~(2)-S(10) 89.6 (3) S(9)-Ru(Z)-S(lO) 72.6 (3) S(6)-Ru(Z)-P(2) 94.8 (3) S ( ~ ) - R U ( ~ ) - P ( ~ ) 91.6 (3) S ( ~ ) - R U ( ~ ) - P ( ~ )179.5 (4) S(9)-Ru(2)-P(2) 93.8 (3) S(lO)-Ru(2)-P(2) 90.7 (3) Ru(2)-S(9)
