Organometallics 1995, 14, 4594-4600
4594
Catalytic Cyclooligomerization of Thietane by Tetraosmium and Tetraruthenium Tetrahydride Carbonyl Cluster Complexes Richard D. Adams" and Stephen B. Falloon Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208 Received May 4, 1995@
OS~(CO)~~(SCHZCHZ~H~)(~-H)~, 3, O S ~ ( C O ) I I ( ~ ~ S ~ ) +4, -H)~, RU~(CO)I~(SCH~CH~CHZ)+-H)~, 5, and R~u(C0)11(12S3)+-H)4,6 (12S3 = 1,5,9-trithiacyThe new compounds
clododecane) have been obtained from the reactions of Os4(CO)11(NCMe)+-H)4and Ruq(C0)12with thietane and 12S3, respectively. The molecular structure of 4 was established by a single-crystal X-ray diffraction analysis. The molecule contains a tetrahedral cluster of four osmium atoms with four bridging hydride ligands and a 12S3 ligand coordinated to one of the metal atoms through one of its three sulfur atoms. Compounds 3 and 4 were found to be efficient catalysts for the cyclooligomerization of thietane to 12S3 and 2486 (2486 = 1,5,9,13,17,21-hexathiacyclotetracosane) with a 6/1 preference for 12S3 aRer a 24 h reaction period. A kinetic study of the catalysis by 4 showed that the formation of 12S3 is first order in the concentration of 4, which is consistent with the catalysis being produced by a tetranuclear cluster complex. Significant amounts of 12S3 and 2486 were also obtained from thietane when 5 and 6 were used as catalyst precursors; however, the selectivity for 12S3 was significantly lower, and analysis after the reactions showed that most of the cluster complexes had decomposed. Crystal data for 4: space group = C2/c, a = 29.904(6) b = 11.815(2) c = 17.633(3) ,B = 91.28(2)", 2 = 8, 3384 reflections, R = 0.058. +-H)4
A,
A,
A,
Introduction
formed from thietane in the presence of Res(CO)l&-
Polythioether macrocycles have attracted considerable interest for their potential to serve as ligands for the transition meta1s.l In the course of our recent studies of the ring opening reactions of the thietane ligands by nucleophile^,^,^ we have discovered the first examples of the formation of polythioether macrocycles by the catalytic cyclooligomerization of thietanes, eq l.4~5 The
(SCH2CH2CH2)@-H)3,4and 12S3 and 2496 are formed
HzC-CHz n l l S-CHz
rhenium clusters
in the presence of R ~ ~ ( C O ) S ( S C H ~ C H ~ C H ~ ) . ~ In previous studies of the reactions of 3,3-dimethylthietane with Osa(CO)lo(NCMe)2,we observed ringopening trimerization, but the cyclization step was preempted by reactions of the trimer at the metal atoms.6 We have now investigated the coordination and reactivity of thietane in the tetraosmium and tetra-
-
I
ruthenium tetrahydride complexes, OS~(CO)~~(SCHZ1
thietane 12S3,n-3
16S4,n-4
2456, n-6
(1) polythioether macrocycles 12S3 = 1,5,94rithiacyclododecane, 16S4 = 1,5,9,13-hexathiacyclohexadecane,and 2496 = 1,5,9,13,17,21-hexathiacyclotetracosaneare @Abstractpublished in Advance ACS Abstracts, September 1,1995. (1) (1)(a) Cooper, S. R. In Crown Compounds: Toward Future Applications, Cooper, S. R., Ed.; VCH Publishers: New York, 1992, Chapter 15. (b) Cooper, S.R.; Rawle, S. C. Struct. Bonding 1990,72, 1. (c) Blake, A. J.; Schroder, M. Adv. Inorg. Chem. 1990,35, 1. (d) Cooper, S. R. Acc. Chem. Res. 1988,21,141. (2)(a) Adams R. D. J . Cluster Sci. 1992,3, 263.(b) Adams, R. D.; Pompeo, M. P. Organometallics 1992, 11, 1460. (c) Adams, R. D.; Belinski, J. A.; Pompeo, M. P. Organometallics 1991, 10, 2539. (d) Adams, R. D.; Belinski, J. A.; Pompeo, M. P. Organometallics 1992, 11, 3129. (3)Adams, R. D.;Cortopassi, J . E.; Falloon, S. B. Organometallics 1992,11, 3794. (4)Adams, R.D.; Falloon, S. B. J . A m . Chem. SOC.1994,116,10540. (5)Adams, R. D.; Cortopassi, J . E.; Falloon, S.B. Organometallics 1995,14, 1748.
CH2CH2)@-Hh,3, and Ru~(CO)~~(SCH~CH~CH~)@-H)~, 5. These complexes also produce appreciable amounts of 12S3 and 2486 by catalytic cyclooligomerizations,but the ruthenium compound undergoes considerable decomposition and produces only small amounts of 12S3. The results of this study are reported here. Experimental Section General Data. Unless otherwise indicated all reactions were performed under a nitrogen atmosphere under normal room-li hting conditions. Reagent grade solvents were stored over 4- molecular sieves. OS~(CO)&-H)~,'1, and Ruq(CO)12@H)4,8 were prepared according to the published procedures. Trimethylamine N-oxide dihydrate (Aldrich) was dehydrated by using a Dean-Stark apparatus with benzene as the solvent prior t o use. 1,5,9-Trithiacyclododecane, 12S3, was prepared
if
(6)Adams, R.D.;Pompeo, M. P. J . Am. Chem. SOC.1991,113,1619. (7)Johnson, B. F. G.; Lewis, J.; Raithby, P. R.; Sheldrick, G . M.; Wong, K. J. Chem. SOC.,Dalton Trans. 1978,673. ( 8 ) Knox, S. A. R.; Koepke, J . W.; Andrews, M. A.; Kaesz, H. D. J . Am. Chem. SOC.1975,97,3943.
0276-7333/95/2314-4594$09.00/00 1995 American Chemical Society
Catalytic Cyclooligomerization of Thietane as described in our previous r e p ~ r t .Thietane ~ was purchased from Aldrich and was purified by vacuum distillation before use. All other reagents were purchased from Aldrich and were used as received. Infrared spectra were recorded on a Nicolet 5DXB FTIR spectrophotometer. lH NMR spectra were obtained on Bruker AM-300, WH-400, and AM-500 spectrometers operating at 300, 400, and 500 MHz, respectively. Separations were performed by TLC in air on Analtech 0.25mm silica gel 60-A F254 plates. Elemental analyses were performed by Oneida Research Services, Whitesboro, N.Y. Preparation of O S ~ ( C O ) ~ ~ ( N C M ~ ) @ A - H102.6-mg )~. amount of Os4(C0)12@-H)4,1 (0.093 mmol), was dissolved in 30 mL of methylene chloride and 20 mL of acetonitrile in a 100-mL three-neck round bottom flask equipped with a stir bar, a reflux condenser, a dropping funnel, and a nitrogen inlet. A 7.0-mg amount of Me3NO (0.094 mmol) was added t o 3 mL of CHzC12; this solution was then placed in the dropping funnel and was added over a 2-min period. The resulting solution was then allowed t o stir at 25 "C for 1 h. The volatiles were removed under vacuum, and the product was separated by TLC using a hexane/methylene chloride 3/2 solvent mixture t o yield 80.3 mg of O S ~ ( C O ) ~ ~ ( N C M ~ ) 2, C ~78%. - H ) ~Spectra , for 2: IR ( Y C O , cm-l, in hexane) 2094 (w), 2061 (vs), 2034 (m), 2023 (m), 2010 (m), 2004 (m), 1985 (m); lH NMR (6, in CDCl3) 2.48 (s, 3H), -18.26 (s,2H), -18.58 (s, 2H).
-
Organometallics, Vol. 14, No. 10, 1995 4595 minor isomer B 17% -18.86 (8,br, lH), -18.94 (s, br, lH), -20.25 ( 8 , br, lH),-22.49 (s, br, 1H)I. Anal. Calcd for 4: C, 18.54; H, 1.71. Found C, 18.60; H, 1.42. The mass spectrum of 4 showed the parent ion at m/e 1296 with an isotope distribution pattern consistent with the presence of four osmium atoms. An ion envelope at 1074 is attributed to M+ - 12S3 ligand. Additional ion envelopes at 1044, 1014, 986, 958, 930, 902, 874, 846, 818, 790, and 762 are attributed to the loss of 12S3 plus 1-11 CO ligands from the parent ion.
-
Preparation of Ru4(C0)11(SCHzCHzCHz)01-H)4,5.A 50mg amount of RIU(CO)&-H)~(0.067 mmol) was dissolved in 20 mL of methylene chloride in a 25-mL three-neck round bottom flask equipped with a stir bar, a reflux condenser, a dropping funnel, and a nitrogen inlet. A 5.0-pL amount of thietane (0.094 mmol) was added to the solution. A 5.0-mg amount of Me3NO (0.094 mmol) was dissolved in 3 mL of CH2Cl2. This solution was then placed in a dropping funnel and added to the first solution over a 2-min period. The resulting solution was stirred at 25 "C for 1 h. The volatiles were then removed under vacuum, and the product was isolated by TLC using a hexanelmethylene chloride 3/2 solvent mixture to yield I
27.0 mg of Ru~(CO)I~(SCH~CH~CH~)(~-H)~, 5, 54%. Spectra for 6: IR (YCO, cm-l in hexane) 2097 (w), 2081 (vs), 2071 (vs), 2043 (vs), 2013 (s), 1960 (w); lH NMR (6, in CDC13) 3.60 (t, 4H, JH-H = 7.8 Hz), 3.00 (9, 2H, JH-H = 7.8 Hz), -17.19 (s, Preparation of OS~(CO)~~(SCHZCH~CHZ)C~-H)~, 3. A 3H), -17.81 (8, 1H). Anal. Calcd for 5: C, 21.26; H, 1.26. 30.6-mg amount of 2 (0.027 mmol) was dissolved in 20 mL of Found C, 21.64; H, 1.02. methylene chloride in a 25-mL three-neck round bottom flask Preparation of R~(C0)11(12S3)@-H)4,6. A 51.3-mg equipped with a stir bar, a reflux condenser, and a nitrogen amount of R&(C0)12(p-H)4 (0.069 mmol) was dissolved in 20 inlet. A 10-pL amount of thietane (0.14 mmol) was added, and mL of methylene chloride in a 25-mL three-neck round bottom the resulting solution was then stirred at reflux for 2 h. The flask equipped with a stir bar, a reflux condenser, a dropping volatiles were removed in vacuo, and the products were funnel, and a nitrogen inlet. A 15.0-mg amount of 12S3 (0.068 separated by TLC using a hexane/methylene chloride 2l1 mmol) was added to the solution. A 5.0-mg amount of Meam solvent mixture to yield 22.3 mg of O ~ ~ ( C O ) I I ( S C H ~ C H ~ C H ~NO ) - (0.067 mmol) was dissolved 3 mL of CHzC12, and this solution was then added t o the first solution over a 2-min ( ~ L - H3,90% ) ~ , yield, and 6.4 mg of unreacted 2. Spectra for 3: period via the dropping funnel. The resulting solution was IR (VCO, cm-l, in hexane) 2100 (w), 2076 (s), 2061 (vs), 2022 stirred at 25 "C for 1h. The volatiles were then removed under (vs), 2010 (s), 2000 (w); lH NMR (6, in CDC13 at 25 "C) 3.81 (t, vacuum, and the product was separated by TLC using a 4H, JH-H = 8.0 Hz), 2.99 (quintet, br, 2H), -18.76 (s, br, 2H), hexanelmethylene chloride 1/1 solvent mixture. This was -20.39 (9, br, 2H); IH NMR (6, in CDzClz at -55 "C) 3.88 (m, recrystallized from hexane/acetone 2/1 t o yield 32.8 mg of Ru4br), 3.58 (m, br), 3.08 (m, br), 2.96 (m, br), 2.64 (m, br); the (C0)11(12S3)(jL-H)4,6,55%. Spectra for 6: IR ( V C O , cm-', in hydride region can be interpreted in terms of three isomers: hexane) 2097 (w), 2072 (vs), 2059 (vs), 2028 (vs), 2013 (s), 1958 the major isomer [43%based on integration, -18.39 (s, br, 2H), (w); lH NMR (6, in CDC13) 3.01 (t, 4H, JH-H= 6.9 Hz), 2.67 -20.51 (s, br, 2H), minor isomer A [36%), -18.98 (s, lH), (m, 8H), 2.02 (9, 4H, JH-H = 6.5 Hz), 1.80 (9, 2H, JH-H = 6.4 -19.39 (s, 2H), -20.96 (s, lH)], and minor isomer B [21%, Hz), -17.16 (9, lH), -17.21 (9, 3H). Anal. Calcd for -18.63 (s, br, lH), -19.08 (s, br, lH), -19.97 (8, br, lH), &l.O(CH3)2CO: C, 27.71; H, 2.81. Found C, 27.15; H, 2.44. -22.25 (s,br, lH)]. The mass spectrum of 3 showed the parent ion at m/e = 1148 with an isotope distribution pattern Catalytic Cyclooligomerizations. All catalytic reactions consistent with the presence of four osmium atoms. An ion were performed under nitrogen in 25-mL three-neck round envelope at 1074 is attributed to Mf - thietane ligand. bottom flasks equipped with a stir bar, a reflux condenser, and Additional ion envelopes at 1044, 1014, 986, 958, 930, 902, a nitrogen inlet by using preweighed amounts of catalyst and 874, 846, and 818 are attributed to the loss of thietane plus thietane in the absence of an added solvent at the reflux 1-9 CO ligands from the parent ion. temperature of the thietane (94 "C). Results of the experiPreparation of O S ~ ( C O ) I ~ ( ~ ~ S ~ )4.@A- H 32-mg ) ~ , amount ments are listed in Table 1. of 2 (0.029 mmol) was dissolved in 20 mL of methylene chloride A typical procedure was as follows: a 6.0-mL amount of in a 25-mL three-neck round bottom flask equipped with a stir thietane (81 mmol) and a 14.0-mg amount (0.012 mmol) of 3 bar, a reflux condenser, and a nitrogen inlet. A 6.0-mg amount were added to the 25-mL three-neck round bottom flask. The of 12S3 (0.027 mmol) was added, and the resulting solution reaction was heated t o reflux and was stirred under nitrogen was then stirred a t reflux for 2 h. The volatiles were removed at this temperature for 24 h. After cooling, the excess thietane under vacuum, and the products were separated by TLC using was removed in vacuo. The resulting residue weighed 402 mg. a hexane/acetone 3/2 solvent mixture to yield 16.2 mg of 0 5 4 An lH NMR spectrum was taken of a portion of the residue (C0)11(12S3)h-H)4,4, 91% yield, and 16.8 mg of 2. Spectra and showed only two products: 1,5,9-trithiacyclododecane, for 4: IR ( Y C O , cm-l in hexane) 2097 (w), 2081 (s), 2072 (vs), 12S39[(6, in CDC13) 2.67 (t, 12H, J H - H = 6.7 Hz), 1.87 (q, 6H, 2026 (vs), 2013 (s), 1956 (w); lH NMR (6, in CDC13 at 25 "C): JH-H = 6.7 Hz)] and 1,5,9,13,17,21-hexathiacyclotetracosane, 3.20 (t,br, 4H), 2.74 (t, 4H, JH-H = 6.2 Hz), 2.64 (t, 4H, JH-H 24S6lo[(6, in CDCl3) 2.60 (t,24H, JH-H = 7.2 Hz), 1.84 (9, 12H, = 6.0 Hz), 2.02 (q,4H, JH-H = 6.2 Hz), 1.80 (q,2H, JH-H = 6.3 JH-H = 7.2 Hz)]. The mole ratio of 12S3/24S6 was 6/1, as Hz), -18.83 (s, br, 2H), -20.47 (s, br, 2H); lH NMR (6, in CD2determined by NMR integration of their resonances in the C12at -66 "C) 3.6-2.9 (m, br), 2.76, (m, br), 2.61 (m, br), 1.95, (m, br), 1.71, (m, br); the hydride region can be interpreted in (9)Rawle, S. C.; Admans, G . A,; Cooper, S. R. J. Chem. Soc., Dalton terms of three isomers: the major isomer [66% of total based Trans. 1988,93. on integration, -18.60 (s, 2H), -20.45 (s, 2H)1, minor isomer (10) Ochrymowycz, L. A.; Mak, C.-P.;Michna, J. D. J. Org. Chem. 1974,14,2079. A [17%, -19.08 (s, lH), -19.99 (8,2H), -21.37 (s, lH)], and
A d a m and Falloon
4596 Organometallics, Vol. 14,No. 10,1995
Table 2. Crystallographic Data for Compound 4
Table 1. Results of the Catalytic Cyclooligomerizations of Thietane by Tetraosmium and Tetraruthenium Cluster Complexes catalyst reagent wt of amount amount productsb ratioc of rctn catalyst" (mg) (mL) (mg) 12S3124S6 time (h) 3 14.0 6.0 373 611 24 3 12.2 6.0 458 411 48 4 12.0 6.0 287 611 24 4' 14.8 6.0 332 811 24 51 14.0 6.0 188 0.711 24 6f 15.0 6.0 110 0.711 24 none 6.0 299 211 24
compd empirical formula fw cryst syst lattice param
TOF for
12S3d 4.6 3.0
c, A
A deg
v, A 3
space group 2 ecalcd dcm3 p(Mo Ka), cm-I temp, ( " 0 2&.,, (deg) no. obsd used (I > 3dI)) no. of variables residuals:" R, R , goodness of fit indicator max shift in final cycle largest peak in final diff map, e/A3 abs coir
0.44
All reactions were performed at the boiling point of thietane, 94 "C in the absence of solvent. Only two products were formed, 12S3 and 2486. This is the combined weight of both products. These weights were corrected for the noncatalyzed decomposition of thietane. These are mole ratios. The NMR integration ratios are half these values, since the molecular weight of 2486 is twice that of 12S3. TOF = (moles of 12S3)/(molesof catalysthr). e This reaction was performed under irradiation from a tungsten lamp. f Substantial decomposition of the cluster complexes occurred during these reactions. g Contains a mixture of several products including 12S3 and 2496.
R
to a 25-mL three-neck round bottom flask equipped with a stir bar, a reflux condenser, a nitrogen inlet, and 14.8 mg (0.011 mmol) of 4. The reaction was heated to reflux and was stirred under nitrogen at this temperature for 24 h with a 100-W tungsten lamp placed 6 in from the reaction flask. After the
29.904(6) 11.815(2) 17.633(3) 91.28(2) 2526(1) C2/c (No. 15) 8 2.76 165.1 20 48.0 3384 326 0.058; 0.055 2.76
b, A
4.7 0.62
Catalytic Cyclooligomerization by 4 in the Presence of Light. A 6.0-mL amount of thietane (81 mmol) was added
1259.37 monoclinic
a, A
4.7
reaction mixture. The products were separated by TLC (on AVICEL F microcrystalline cellulose) using a hexandchloroform/ ethyl acetate 2/1/1 solvent mixture as the eluent to give two bands. The first band contained the macrocycle 12S3,4and the second band contained the macrocycle 24S6.5 In general, the nonvolatile residues are completely soluble in methylene chloride, which indicates the near absence of polymer formation. The results of these tests are listed in Table l. The results are corrected for the noncatalytic decomposition of thietane, see below. Reactions performed with the rigorous exclusion of light or under irradiation by a 100-W tungsten lamp produced similar results, see below. Catalytic Cyclooligomerizationof Thietane by 3, "Long Term"Test. Under a nitrogen atmosphere was added 6.0 mL (81.0 mmol) of thietane to a 25-mL three-neck round bottom flask equipped with a stir bar, a reflux condenser, a nitrogen inlet, and 12.0 mg (0.010 mmol) of 3. The thietane itself served as the solvent in this reaction. The solution was heated to reflux and was stirred under nitrogen at this temperature for 48 h. After the solution had been cooled, the unreacted thietane was removed in vacuo. The resulting residue weighed 516 mg. An 'H NMR spectrum was taken of a portion of the residue. It showed the presence of only two organic products: the mole/mole ratio of 12S3/24S6 was 4/1 as determined by an NMR integration of the resonances. Study of the Dependence of the Rate of Catalysis on the Concentration of 4. In a typical procedure a 6.0-mL amount of thietane (81 mmol) was added to a 25-mL threeneck round bottom flask equipped with a stir bar, a reflux condenser, and a nitrogen inlet. An appropriate amount of the catalyst 4 was added under nitrogen. All measurements were made a t 93.0 f 0.1 "C for a period of 1 h and were performed in duplicate. At the end of 1h, the excess thietane was removed under vacuum, and the amount of product was then determined by weighing the resulting residue and subtracting the preweighed weight of the catalyst. At this short reaction time, the NMR spectra of the residues showed the presence of only one organic product, 12S3. An NMR spectrum recorded in the hydride region at -55 "C could be explained completely as a mixture of 4 (>97% total) and 3 (13% total).
4 0~4S30iiC2oHzz
0.00
2.57 empirical
-
-
Chkl(IlFobsd1 l F c a l c d l I ~ h k l l F o b s d l ; R w = &klW(/Fobsdl l ~ c a l ~ d 1 ~ ) ~ h k l W F a b s dW ~ ] "=~ ,l/U2(Fobsd); = %kl( IFobsdl lFcalcd// 'J(Fobsd)y(ndata &aril.
=
-
GOF
-
solution had been cooled, the excess thietane was removed in vacuo. The resulting residue weighed 361 mg. A 'H NMR spectrum was taken of a portion of the residue and showed that it consisted entirely of 1283 and 2486 in a mole ratio of 8/1. Catalytic Cyclooligomerizationof Thietane with 5 for 1 h. Under a nitrogen atmosphere was added 6.0 mL (81.0 mmol) of thietane to a 25-mL three-neck rouns borrom flask equipped with a stir bar, a reflux condenser, a nitrogen inlet, and 15.0 mg (0.019 mmol) of 5. The thietane itself served as the solvent in this reaction. The solution was heated to reflux and was stirred under nitrogen at this temperature for 1 h. After cooling, the unreacted thietane was removed in vacuo. The resulting residue weighed 45 mg. An 'H NMR spectrum was taken of the entire residue. The spectrum showed the presence of only two organic products, 1283 and 2486 in a mole ratio of 0.7/1 as determined by an NMR integration of the resonances. It was also noted that no hydride resonances remained, indicating that there were no hydride-containing clusters present in solution. The products of the reaction were separated by TLC using a hexanelmethylene chloride 211 solvent mixture to yield 3.0 mg of 5. No other carbonyl containing products could be identified.
Noncatalyzed Thermal Transformationsof Thietane. A 6.0-mL amount of thietane (81 mmol) was added t o a 25mL round bottom flask equipped with a stir bar, a reflux condenser, and a nitrogen inlet. The liquid was brought to reflux and was maintained at this temperature with stirring for 24 h. After cooling, the volatiles were removed in vacuo at room temperature. The residue weighed 29 mg. A 'H NMR spectrum of the residue exhibited the following resonances ( 6 , in CDCl3): 5.79 (m, unknown), 5.10 (m, unknown), 3.66 (m, unknown), 3.08 (t, unknown), 2.64 (t, 12831, 2.57 (t, 24361, 1.84 (quintet, 12S3+2486), 1.26 (m, unknown), 0.94 (t, unknown), and 0.02 (s, silicone grease). The mole ratio of 1283/ 2486 was 2/1 as determined by NMR integration. The products were separated by TLC using hexane/CHzClZ 2/1 solvent mixture 3s the eluent to give three bands: the first band contained silicone grease (4.8 mg) from the joints of the reaction equipment, the second band contained the macrocycle 1283 (4 mg), and the third band (9 mg) consisted of a mixture 2486 and some of the unidentifiable organic products. Crystallographic Analyses. Light yellow crystals of 4 suitable for X-ray diffraction analysis were grown from solution in a 2/1 CHzClz/hexane solvent mixture by slow evaporation
Organometallics, Vol. 14, No. 10, 1995 4597
Catalytic Cyclooligomerization of Thietane
Table 3. Positional Parameters and B(eq) Values (As>for 4 atom
X
Y
z
B(eq)
Os(1) Os(2) Os(3) Os(4)
0.68705(4) 0.65259(4) 0.62431(3) 0.58932(3) 0.5791(2) 0.6302(4) 0.5552(3) 0.729(1) 0.699(1) 0.7756(7) 0.6814(9) 0.5967(9) 0.737(1) 0.5928(6) 0.5430(7) 0.6815(7) 0.5485(8) 0.5037(7)0.568(1) 0.612(1) 0.650(1) 0.659(1) 0.633(1) 0.587(1) 0.547(1) 0.522(1) 0.528(1) 0.713(1) 0.694(1) 0.741(1) 0.669(1) 0.6164(9) 0.706(1) 0.6041(9) 0.5735(9) 0.658(1) 0.567(1) 0.536(1)
0.07705(7) -0.04221(7) -0.11109(6) 0.08826(7) 0.2569(4) 0.5849(5) 0.4370(6) 0.259(2) 0.192(2) -0.055(2) 0.139(2) -0.183(1) -0.176(2) -0.052(1) -0.250(1) -0.316(1) 0.192(2) -0.027(2) 0.380(2) 0.421(2) 0.459(2) 0.568(2) 0.495(2) 0.534(2) 0.317(2) 0.340(2) 0.251(2) 0.191(2) 0.154(2) -0.006(2) 0.072(2) -0.130(2) -0.128(2) -0.074(2) -0.199(2) -0.240(2) 0.150(2) 0.015(2)
0.20287(5) 0.07589(5) 0.22866(4) 0.16731(4) 0.0911(3) 0.0789(4) -0.1490(3) 0.108(1) 0.356(1) 0.210(1) -0.038(1) -0.036(1) 0.062(1) 0.3861(8) 0.190(1) 0.278(1) 0.3076(9) 0.120(1) 0.150(1) 0.186(1) 0.130(1) -0.010(1) -0.065(1) -0.090(1) -0.086(1) -0.019(1) 0.038(1) 0.142( 1) 0.303(1) 0.207(1) 0.003(1) 0.007(1) 0.064( 1) 0.327(1) 0.204(1) 0.263(1) 0.255(1) 0.139(1)
3.23(4) 3.01(4) 2.62(4) 2.61(4) 3.8(3) 6.9(5) 6.7(5) lO(2) 15(2) 9(1) 11(2) 9(1) 15(2) 5(1) 7(1) 7(1) 7(1) 9(1) 5(1) 7(2) 6(2) 6(2) 5(1) 7(2) 4(1) 50) 5(1) 5.7(6) 5.1(6) 5.4(6) 4.9(6) 3.8(5) 5.7(6) 4.2(5) 3.9(5) 4.2(5) 4.8(6) 5.4(6)
S(1)
c4
S(2) S(3) s2 O(11) O(12) O(13) O(21) O(22) O(23) O(31) O(32) O(33) O(41) O(42) C(1) C(2) W C(3) Figure 1. ORTEP diagram of O S ~ ( C O ) ~ ~ ( ~ ~ S ~ )4, O L - H )C(4) ~, C(5) showing 50%probability thermal ellipsoids. C(6) C(7) of solvent at 25 "C. The crystal used in intensity measureC(8) ments was mounted in a thin-walled glass capillary. DiffracC(9) tion measurements were made on a Rigaku AFC6S fully C(11) automated four-circle difiactometer using graphite-monochroC(12) mated Mo K a radiation. The unit cells were determined and C(13) C(21) refined from 15 randomly selected reflections obtained by using C(22) the AF'C6S automatic search, center, index, and least-squares C(23) routines. Crystal data, data collection parameters, and results C(31) of these analyses are listed in Table 2. All data processing C(32) was performed on a Digital Equipment Corp. VAXstation 3520 C(33) computer by using the TEXSAN structure-solving program C(41) library obtained from the Molecular Structure Corp., The C(42)
Woodlands, TX. Neutral atom scattering factors were calculated by the standard procedures.lla Anomalous dispersion corrections were applied to all non-hydrogen atoms.llb Lorentzpolarization (Lp) and absorption corrections were applied in each analysis. Full matrix least-squares refinements minimized the function: &lW(lFol - IFc1)2,where w = l/df12, u(F)= dF,2)/2Fo, and dFo2) = [d1,,,)2 + (0.02 (1n,t)211'2/Lp. Compound 4 crystallized in the monoclinic crystal system. The space group P21In was established on the basis of the patterns of systematic absences observed during the collection of data. The structure was solved by a combination of direct methods (MITHRIL) and difference Fourier syntheses. All atoms heavier than carbon were refined with anisotropic thermal parameters. The carbon atoms in the 12S3 ring were also refined anisotropically. The positions of the hydrogen atoms on the 12S3 ligand were calculated by assuming idealized geometries and C-H = 0.95 A. Their contributions were added t o the structure factor calculations, but their positions were not refined. The hydride ligands were not located in the analysis and were ignored.
Results Treatment of t h e compound Os4(CO)ll(NCMe)@-H)4 with t h i e t a n e a n d 12S3 produced t h e compounds
OS~(CO)~~(SCH~CH~CH~)@-H)~, 3,and 0~4(CO)11(12S3)@-H)4,4, in t h e yields 90% and 91%, respectively. Both compounds were characterized by a combination of IR and lH NMR spectroscopy. Compound 4 w a s also characterized by a single-crystal X-ray diffraction analy~
(11)(a) International Tables for X-ray Crystallography; Kynoch Press: Birmingham, England, 1975; Vol. IV,Table 2.2B, pp 99-101. (b)Ibid., Table 2.3.1,pp 149-150.
Table 4. Intramolecular Distances for 4= Os(l)-Os(2) 0~(1)-0~(3) 0~(1)-0~(4) Os(l)-C(ll) Os(l)-C(12) Os(l)-C(13) 0~(2)-0~(3) 0~(2)-0~(4) Os(2)-C(21) Os(2)-C(22) 0~(2)-C(23) 0~(3)-0~(4) 0~(3)-C(31) 0~(3)-C(32) 0~(3)-C(33) Os(4)- S( 1)
2.821(1) 2.951(1) 2.978(1) 1.89(3) 2.00(2) 1.89(3) 2.956(1) 2.948( 1) 1.94(2) 1.92(2) 1.90(3) 1.786(1) 1.90(2) 1.88(2) 1.92(2) 2.419(5)
0~(4)-C(41) 0~(4)-C(42) S(l)-C(l) S(l)-C(9) S(2)-C(3) S(2)-C(4) S(3)-C(6) S(3)-C(7)
0-C(av) C(l)-C(2) C(2)-C(3) C(4)-C(5) C(5)-C(6) C(7)-C(8) C(8)-C(9)
1.84(2) 1.88(3) 1.82(2) 1.78(3) 1.82(3) 1.81(3) 1.80(3) 1.81(2) 1.14(3) 1.54(5) 1.57(4) 1.51(4) 1.50(4) 1.44(3) 1.47(3)
a Distances are in angstroms. Estimated standard deviations in the least significant figure are given in parentheses.
sis. An ORTEP diagram of the molecular stucture of 3 is shown in Figure 1. Final atomic positional parameters are listed in Table 3. Selected intramolecular distances and angles a r e listed in Tables 4 and 5 , respectively. The molecule is structurally similar t o t h e compound OS~(CO)~~[P(OM~)~]@-H)~, 7 , which has been characterized structurally both by X-ray and neutron diffraction analysis.12 Both compounds contain closed tetrahedral clusters of four osmium atoms. In 7 t h e hydride ligands were structurally located a n d refined. In 4 t h e hydride ligands were not located, b u t four of (12) Wei, C.-Y.; Garlaschelli, L.; Bau, R. J.Organomet. Chem. 1981, 213, 63.
Adams and Falloon
4598 Organometallics, Vol. 14, No. 10, 1995 Table 6. Intramolecular Bond Angles for 4a 0 ~ ( 2 ) - 0 ~ ( 1 ) - 0 ~ ( 3 ) 61.56(3) 0 ~ ( 2 ) - 0 ~ ( 1 ) - 0 ~ ( 4 ) 61.04(4) 0 ~ ( 3 ) - 0 ~ ( 1 ) - 0 ~ ( 4 ) 56.06(3) O s ( l ) - O ~ ( 2 ) - 0 ~ ( 3 ) 61.38(3) 0 ~ ( 1 ) - 0 ~ ( 2 ) - 0 ~ ( 4 ) 62.12(4) 0 ~ ( 3 ) - 0 ~ ( 2 ) - 0 ~ ( 4 ) 56.32(3) 0 ~ ( 1 ) - 0 ~ ( 3 ) - 0 ~ ( 2 ) 57.06(3) OS(l)-Os(3)-0~(4) 62.48(4) 0 ~ ( 2 ) - 0 ~ ( 3 ) - 0 ~ ( 4 ) 61.71(3) 0 ~ ( 1 ) - 0 ~ ( 4 ) - 0 ~ ( 2 ) 56.84(3) O ~ ( l ) - O s ( 4 ) - 0 ~ ( 3 ) 61.47(3) 0 ~ ( 1 ) - 0 ~ ( 4 ) - S ( l ) 105.3(2) 0 ~ ( 2 ) - 0 s ( 4 ) - 0 ~ ( 3 ) 61.98(3) Os(2)-Os(4)-S(l) 101.6(2) Os(3)-0s(4)-S(l) 162.5(2) S(l)-Os(4)-C(41) 95.7(8)
S(1)-0~(4)-C(42) 0~(4)-S(l)-C(l) 0~(4)-S(l)-C(9) C(l)-S(l)-C(9) C(3)-S(2)-C(4) C(6)-S(3)-C(7) S(l)-C(l)-C(2) C(l)-C(2)-C(3) S(2)-C(3)-C(2) S(2)-C(4)-C(5) C(4)-C(5)-C(6) S(3)-C(6)-C(5) S(3)-C(7)-C(8) C(7)-C(8)-C(9) S(l)-C(9)-C(8) Os-C-O(av)
97.9(8) 111.1(8) 110.7(8) lOO(1) lOl(2) 103(1) 109(2) 117(2) 109(2) 112(2) 118(3) 116(2) 116(2) 112(2) 115(2) 175(2)
a Angles are in degrees. Estimated standard deviations in the least significant. figure are given in parentheses.
the osmium-osmium bonds are significantly longer than the other two: Os(l)-Os(3) = 2.951(1) A, Os(1)Os(4) = 2.978(1) A, 0 ~ ( 2 ) - 0 ~ ( = 3 )2.956(1) A, and OS(2)-Os(4) = 2.948(1) A versus Os(l)-Os(2) = 2.821(1) A and Os(3)-Os(4) = 2.786(1) A. These long bonds exhibit the same disposition as the hydride-bridged metal-metal bonds in 7 which are also similarly elongated.12 Accordingly, it is assumed that the hydride ligands in 4 bridge the four long metal-metal bonds.
is attributed to the isomer as observed in the solid state. There are minor isomers A (17% of total), which exhibits three resonances [-19.08 (lH), -19.99 (2H), -21.37 (lH)], and B (17% of total), which exhibits four resonances [-18.86 (5, br, lH), -18.94 (s, br, lH), -20.25 (s,br, lH), -22.49 (s,br, 1H)I. Without additional data it is not possible to identify these isomers uniquely, but it is believed that they are formed by different arrangements hydride ligands about the six metal-metal bonds. These isomers are dynamically averaged at room temperature as a result of rapid hydride ligand shifts between the different metal-metal bonds. Facile hydride ligand shifts in related tetraruthenium tetrahydride carbonyl cluster complexes have been observed previ0us1y.l~ The IR spectrum and lH NMR spectrum of 3 in the hydride ligand region are very similar to those of 4. Accordingly, it is proposed that the structure of 3 is
Ti L') 4'
/os-
-0rC
08'
'I\
3
4
7
analogous to that of 4 with the substitution of a thietane ligand in the position of the 1253 ligand. Compound 3 also exists in solution as a mixture of isomers similar to those found for 4. This was confirmed by examining the lH NMR a t -55 "C, which indicated three isomers: the major isomer 43%, with resonances at -18.39 and -20.51 ppml and two lessor isomers, A 36%, -18.98 (lH), -19.39 (2H), and -20.96 (1H) ppml and B [(21%, -18.63 (lH), -19.08 (lH), -19.97 (lH), -22.25 (1H) PPmI. The reaction of Ru(CO)&-H)4 with thietane and 12S3 in the presence of Me3NO t o assist in decarbony-
The 12S3 ligand is coordinated t o only one metal atom of the cluster using only one of its three sulfur atoms, S(1),Os(4)-S(l) = 2.419(5)A. The conformation of the I 12S3 ligand is similar to that observed for the free lation provided the new compounds Ru4(CO)11(SCHz1 molecule9 and other complexes in which only one of the sulfur atoms serves as a site for metal b i n d h ~ g . ~ ~ ~ J ~CH&Hz)b-H)4, 5, 54%, and Ru4(C0)11(12S3)b-H)4,6, 55%, respectively. On the basis of the strong similariAt 25 "C the lH NMR spectrum of 4 exhibits two very ties of the IR spectra of these compounds t o the osmium broad strongly shielded resonances a t 6 = -18.83 (s, 3 and 4 and to known monophosphine- and compounds 2H) and 6 -20.47 (9, 2H) due to the hydride ligands. monophosphite-substituted derivatives of RUq(CO)d,uThis is consistent with the solid state structure. The H)4,16 it can be safely concluded that all of these resonances displayed by the 12S3 ligand are also compounds have structures about the clusters that are consistent with the solid state structure: 3.20 (t,br, 4H), analogous to that of 4. 2.74 (t,4H, JH-H= 6.2 Hz), 2.64 (t,4H, JH-H= 6.0 Hz), Catalytic Cyclooligomerization of Thietane. 2.02 (q,4H, JH-H= 6.2 Hz), 1.80 (q,2H, JH-H= 6.3Hz). When solutions of 3 or 4 were dissolved in thietane in Interestingly, when the temperature is lowered, the of solvent and then heated to reflux, the the absence hydride resonances broaden and then resolve into a new macrocycles 12S3 and 2486 were formed catalytically. pattern, which indicates that the molecule exists in No other cyclooligomers were formed. The results are solution as a mixture of at least three isomers. For example, the spectrum of 4 a t -66 "C exhibits nine (14)(a) Churchill, M.R.; Lashewycz, R. A.; Shapley, J. R.; Richter, resonances in the hydride region. The major isomer S. I. Znorg. Chem. 1980,19, 1277. (b) Shapley, J . R.; Richter, S. I.; Churchill, M. R.; Lashewycz, R. A. J . Am. Chem. Soc. 1977,99,7384. (66% of total based on integration) exhibits two reso(c) &ox, S. A. R.; Kaesz, H. D. J . Am. Chem. SOC.1971,93,4594. nances, -18.60 and -20.45 ppm, of equal intensity and (15)Laine, R. M. J. Mol. Cutul. 1982,14,137.(b) Hilal, H. S.; Jondi, (13)(a) Edwards, A. J.; Johnson, B. F. G.; Khan, F. IC; Lewis, J.; Raithby, P. R. J. Orgunomet. Chem. 1992,426,C44. (b) Blower, P. J.; Clarkson, J. A.; Rawle, S. C.; Hartman, J. R.; Wolf, R. E.; Yagbasan, R.; Bott, S. G . ; Cooper, S. R. J . Chem. Soc., Dalton Trans. 1989,28, 4040.
W.; Khalaf, S.; Abu-Halawa, R. J . Orgunomet. Chem. 1993,452,161. (c) Hilal, H. S.; Khalaf, S.; Jondi, W. J. Orgunomet. Chem. 1993,452, 167. (16)Bruce, M.I. Comprehensive Organometallic Chemistry; Wilkinson, G . , Stone, F. G. A., Abel, E., Eds.; Pergamon, Oxford, 1982; Chapter 32.6,Table 2,p 894.
Catalytic Cyclooligomerization of Thietane
Organometallics, Vol.14,No.10,1995 4599
0.2
f
c)
fn
2
-
0.1
0
E
E
0
1
;
;
-
1
4
Concentratlon of 4 mmol/L
Figure 2. Plot of the rate of formation of 12S3 as a function of the concentration of 2. Rates were determined after the first 1 h of reaction time. listed in Table 1. After a period of 1 h, only 12S3 was observed. After a period of 24 h, both 12S3 and 2486 were observed, but the amount of 12S3 was greater than six times the amount of 2486. After a period of 48 h, the mole ratio 12S3/24S6 was about 4/1; thus, it appears that the amount of 2496 does increase relative to that of the 12S3 as the reaction progresses. The catalytic activity and selectivity for 12S3 and 2486 formation are virtually the same for 3 and 4. The average turnover frequency (TOF)for the formation of 12S3 is about 4 . 7 k in the 24-h reaction period. A study of the rate of reaction as a function of the concentration of 4 showed a linear dependence in the concentration range (0.73.2) x M, see Figure 2. This is consistent with the catalyst being a tetranuclear species and argues against a process involving cluster fragmentation.15 After one of the 1h tests, the thietane solvent was removed under vacuum and an lH NMR spectrum of the residue was recorded in the hydride region at -55 "C. All of the observed resonances could be explained in terms of the presence of two compounds: 3 (
