Organometallics 1995, 14, 2490-2495
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ortho- and meta-(Diethynylcyclopentadieny1)tricarbonylmanganese: Building Blocks toward the Construction of Metal Fragment Supported Fullerenynes? Uwe H. F. Bunz,* Volker Enkelmann, and Frank Beer Max-Planck-Institut fur Polymerforschung, Ackermannweg 21, 55021 Mainz, FRG Received November 22, 1994@ Starting from [(trimethylsilyl)ethynyllcymantrene(l),the two isomeric 1,2- and 1,3-[bis(trimethylsily1)ethynyllcymantrenes (3a,4a)were prepared by a deprotonatiordiodinatiod coupling sequence. The coupling reaction was performed on the mixed ortho-lmetaiodo[(trimethylsilyl)ethynyllcymantrenes (2) by using Stille methodology (tin alkynes and PdC12(CH3CN)2as catalyst in ethyl ether/DMF). Separation of the isomers (3a,4a) is achieved by chromatography over flash silica gel. The ortho-diethynylcymantrene 3a is isolated in 42%, while the corresponding meta compound 4a is formed in 26%. If the deprotonation reaction of 1 in pentane/TMEDA is performed under carefully controlled conditions (-78 “C), the formation of only ortho 2 is observed in 67% yield. Coupling with trimethylstannyl(trimethylsily1)acetylene furnished 3a in 57%. Crystal structures have been carried out for complexes 3a (C2/c; a = 29.923(1), b = 15.9145(7),c = 9.327(1) A, a = 90, p = 102.920(7), y = 90”; V = 4329.1(6) Hi3; 2 = 8; 2948 reflections with F > 3dF); R = 0.071, R, = 0.074) and 4a (P212121; a = 17.027(3),b = 12.339(4),c = 10.235(2)A; a = ,8 = y = 90”; V = 2150(1) Hi3; 2 = 4; 1392 reflections with F > 3dF); R = 0.059, R, = 0.058). Removal of the alkyne-bound trimethylsilyl groups is achieved in yields of >80% by treatment of 3a and 4a with potassium carbonate in methanol. The parent diethynylcymantrenes (3b,4b) are stable compounds. Treatment of 1,2-diethynylcymantrene3b under Hay conditions gives coupled material, a polymer poly[(ortho-cymantrene)butadiynylenel ( 6 )in 68% yield ( M , = 9300). If the Hay reaction is conducted with 3b and a n added capping reagent (ethynylcymantrene), a series of oligomeric butadiynylenecymantrenes is isolated starting from the dimer up to the heptamer (dimer 7a,8.2%; trimer 7b, 12.5%; tetramer 7c, 7.7%; pentamer 7d, 5.5%;hexamer 7e, 3.6%; heptamer 7f,2.5%; E = 40%). The compounds were separated by chromatography over flash silica gel or preparative HPLC. The oligomers 7 are unstable lemon yellow powders.
Introduction Research on “all-carbon molecules”, carbon allotropes, and carbon-rich networks has exploded1” since the isolation and characterization of c60 and c 7 0 by Kratschmer, Fostiropolous, and Huffmannlbin 1990 and the observation of cyclocarbons in 1991 by Rubin and Diederich.l” Substantial progress has been made in the synthesis of segments of c60. While Scott et al. and Siegel et al. prepared corannulenelC in preparative quantities, Schliiterldwas able to synthesize belt-shaped segments of 0,coined “buckypeels”. An almost ubiquitous feature of two- and threedimensional carbon nets (with exception of the fullerenes) Abstract published in Advance ACS Abstracts, April 1, 1995. (1)(a) Bunz, U. H. F.Angew. Chem., Int. Ed. Engl. 1994,33,1073. Diederich, F. Nature 1994,369, 199. Diederich, F.; Rubin, Y. Angew. Chem., Int. Ed. Engl. 1992, 31, 1101. Gleiter, R.;Kratz, D. Angew. Chem., Int. Ed. Engl. 1993,32,842. (b) Kratschmer,W.; Lamb, L. D.; Fostiropoulos, K.; Huffmann, D. R. Nature 1990,347,354. Hammond, G. S., Kuck, V. J., Eds. Fullerenes, ACS Symposium Series 481; American Chemical Society: Washington, DC, 1992. (c) Scott, L.T.; Hashemi, M. M.; Meyer, D. T.; Warren, H. B. J . A m . Chem. SOC.1991, 113, 7082. Borchardt,A.; Fuchicello, A.; Kilway, A. V.; Baldridge, K. IC: Siegel, J. S. J . Am. Chem. Soc. 1992, 114, 1921. (d) Schliiter, A. D.; Lamer, M.; Enkelmann, V.Nature 1994,368,831. (e) Expanded pentafulvenes with a pentatetraene linkage: Haher, K. Pure Appl. Chem. 1990, 62, 531. @
Figure 1. Clso-fullerenyne consisting of five-membered Mn(CO)a-supportedrings and butadiyne units. is the alkyne unit as versatile and reactive functional group of sufficient shape stability. Very recently a novel type of “exploded fullerenes”, the fullerenynes, was proposed by the Allied-Signal group.2 These carbon allotropes can be envisioned by introducing two or four sp-hybridized carbon atoms between the original fullerene (2) Baughman, R. H.; Galvlo, D. S.; Cui, C.; Wang, Y.; TomPnek, D. Chem. Phys. Lett. 1993,204, 8.
0276-733319512314-2490$09.00/0 0 1995 American Chemical Society
Organometallics, Vol. 14, No. 5, 1995 2491
(Diethynylcyclopentadieny1)tricarbonylmanganese
Scheme 1 SiMe3 Mc3Sn-Mc3
rcc.BuLilEt20/ -55°C
b
I-cH,-QI,-I. 81 40
PdCi#I13CN),/DMF
(co),&in 2
1
Me3Si \
,SiMel
I
K,CO,IMcOH
874
'1
K2C031McOH 86%
H
3b
H
carbons. Some of the proposed species consist of merely allene-type structures where every six-membered ring is blown up and the five-membered rings of (260 are still intact. Containing merely allene structures will hamper the isolation of macroscopic amounts of these species (if formed) severely, due to their expected instability toward polymerization.le Stabilization might be possible though by selective complexation of the fivemembered rings by the Mn(C0)3 group or a similar fragment (see Figure 1)to yield an isolable organometallic fullerenyne. It seemed an attractive goal to us to synthesize segments of these species. In this publication we wish t o report on the synthesis of linear segments of an organometallic fullerenyne depicted in Figure 1. When we started our investigation, only one example of a Cp ring carrying five ethynyl groups3 was known. Cp complexes with two ethynyl groups on one ring (the necessary building blocks for fullerenyne segments) were not described in the literature. This is different for the well-known 1,l'-diethynyls derived from ferr ~ c e n e the , ~ fair number of published monoethynyl substituted sandwich and half-sandwich c ~ m p l e x e s , ~ and the increasing number of diethynylated cyclobutadiene c ~ m p l e x e s . ~ , ~ Results and Discussion Synthesis of the Monomers 3b and 4b. Our strategy to build the desired monomers, the diethynyls 3 and 4,rests on a reaction sequence already employed (3)Bunz, U.H.F.; Enkelmann, V.; Rader, J. Organometallics 1993, 12,4745.
4b
H
by Stille5for the synthesis of monoethynyl cymantrenes. Compound 1,available in 10-g quantities, was treated with 1.2 equiv of sec-BuLi in ethyl ether at -55 "C (Scheme 1) and reacted with a slight excess of 1,2diiodoethane. During the course of the hctionalization a vigorous evolution of gas took place, presumably ethylene. After aqueous workup a mixture of compounds 2 was obtained as a yellow oil by filtration over flash silica gel. A proton NMR spectrum taken from a sample of this oil showed considerable broadening of the displayed signals. Attempts t o further separate the mixture by thin layer or column chromatography were not met by success, so the material was used without further characterization in the following coupling step utilizing (trimethylstannyl)(trimethylsilyl)ethyne ( 5 )as reaction partner and Beletskaya's catalysts (PdClz(CH3CN)d in a DMF/ethyl ether mixture (1h reaction time, 5 mol % catalyst, -20 "C +21 "C). After removal of the solvent the dark residue was filtered over a plug of flash silica gel to give a waxy yellow solid which was repeatedly chromatographed (flash silica gel, pentane/
-
(4)Schlogl, K.; Steyrer, W. Monatsh. Chemie, 1 M , 96, 1520. Buchmeiser, M.;Schottenberger, H. J. Organomet. Chem. 1992,441, 457. Buchmeiser, M.; Schottenberger, H. J. Organomet. Chem. 1992, 436,223.Pudelski, J. K.; Callstrom, M. R. Organometallics 1992,11, 2757. Doisneau, G.;Balvoine, G.; Fillebeen-Khan, T. J. Organomet. Chem. 1992,425,113. (5)Bunel, E. E.; Valle, L.; Jones, N. L.; Caroll, P. J.; Gonzalez, M.; Munoz, N.; Manriquez, J . M. Organometallics 1988,7, 789. Rausch, M. D.; Siegel, A.; Kleman, L. P. J. Org. Chem. 1969,31, 2703. Lo Sterzo, C.; Stille, J. K. Organometallics 1990,9, 687. (6)Altmann, M.: Bunz. U. H. F. Makromol. Chem. Rapid Commun. 1994,15,785.'B&z, U.H.F.; Enkelmann, V. Angew. Chem., Int. Ed. Engl. 1993,32, 1653. (7)Fritch, J. R.; Vollhardt, K. P. C. Organometallics 1982,1, 590. (8)Beletskaya, I. P. J. Organomet. Chem. 1983,250,551.
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Figure 2. ORTEP drawing of 3a with the numbering scheme. Hydrogen atoms were omitted for clarity. Selected bond lengths (A) and angles (deg): Cl-C6 1.42(1), C6-C7 1.19(1), C8-C9 1.19(1), C1-C2 1.44(1), C2-C3 1.43(1), C3-C4 1.43(l),C4-C5 1.38(1),Cl-C5 1,42(1);Cl-C6-C7 179.4(11), C2-C8-C9 179.6(1), C 2 - C l - G 106.0 (8).
Figure 3. ORTEP drawing of 4a with the numbering scheme. Hydrogen atoms were omitted for clarity. Selected bond lengths (A) and angles (deg): C6-C7 1.19(1), C8-C9 1.19 ( l ) , Cl-C6 1.42(1), C3-C8 1.40(1), Cl-C2 1.44(1), Cl-C5 1.42(1), C2-C3 1.43(1), C3-C4 1.43(1), C4-C5 1,38(1); C6-Cl-C2 126.2(8), C6-Cl-C5 127.6(8), C3-C2-C1 109.2(8), C8-C3-C2 126.9(9). The trimethylsilyl groups are rotationally disordered, and for clarity only the major occupied site (62%) is shown.
ethyl ether as eluent) leading to the isolation of two fractions from which the latter unequivocally was identified by X-ray crystallography to be 3a (Figure 2) and the forerun being a mixture of two compounds. Distillation of the forerun (0.1 mmHg) yielded as a first reaction 1, unchanged starting material, and as second fraction (130 "C bath) a compound which was identified by its nuclear magnetic resonance spectra and its IR spectrum to be the meta isomer 4a.9 This structural assignment of 4a was corroborated by a crystallographic study (see Figure 3). In a second experiment the metalation reaction was carried out in pentane a t -78 "C. After 5 min tetramethylethylenediamine (12 equiv) was introduced into the reaction mixture. After 1 h at -78 "C, addition of 1,2diiodoethane lead to vigorous evolution of ethylene. After workup and chromatography a yellow oil, ortho (9)Brandsma, L.;Hommes, H.; Verkruijsse, H. D.; de Jong, R. C. P. Red. Trav. Chim. Pays-Bas 1986,104, 226.
2, was isolated in 67% yield showing very broad resonances in the proton NMR, probably due to the occurrence of a paramagnetic trace impurity, so the palladium-catalyzed coupling with tin alkyne 5 was performed without further characterization of the obtained material (vide supra, Scheme 1). Workup and chromatography (flash silica gel, pentane removes unreacted 1;92% pentane/dichloromethane) affords light yellow crystals Of 3a (57%). No detectable amounts Of 4a were isolated. It is known for the examples of ethynylben~ene,~ ethynylthiophene,1° and tricarbonyl(ethynylcyc1obutadienelironll that deprotonation with excess KOtBuBuLi or sec-BuLi, respectively, preferably occurs in the ortho (10)Soloki, D.; Bradshaw, J. D.; Tessier, C. A.; Youngs, W. J. Organometallics 1994,13, 451. (11) (a) Wiegelmann, J. E. C.; Bunz, U. H. F.; Schiel, P. Organometallics 1994,13, 4649. Bunz, U.Organometallics 1993,12, 3594. (b)Independently Hafner and Appel discovered that the deprotonation of tricarbonyl(cyc1obutadiene)iron also takes place with lithium tetramethylpiperidide: Appel, R. Ph.D. Thesis, Darmstadt, 1991.
Organometallics, Vol. 14, No. 5, 1995 2493
(Diethynylcyclopentadieny1)tricarbonylmanganese
Scheme 2
w
acetond2hlfO "C-
3b
position to the triple bond giving access to the corresponding ortho-substituted benzenes, thiophenes, and cyclobutadiene metal complexes. Exactly the same behavior is observed here; under suitable conditions merely ortho lithiation takes place, while at higher temperature and in ethyl ether as solvent the meta position in 1 is attacked as well. The bond lengths and bond angles in both structures are in good agreement with the expected values. In 3a the distance C7-C9 is 4.43 A, which is ca. 0.3 A more than in the parent cis-1,2-diethynylethylene,indicating that a Bergman type rearrangemenP should be possible only a t temperatures '250 "C. In 4a the angle between the two alkyne arms is 143" and additionally the two trimethylsilyl groups are rotationally disordered. The two isomers 3a, 4a do not show signs of decomposition during storage at ambient conditions for several days and are completely stable for an indefinite period of time when kept a t -18 "C. Deprotection of the silylated diethynyls is achieved in 87 and 86% yields by stirring 3a, 4a with potassium carbonate in methanol a t 20 "C for 15 min. The deprotected diethynyls 3b and 4b are obtained analytically pure and are stable under atmospheric conditions for several hours. They can be stored at -30 "C indefinitely. Hay Coupling Experiments with 3a. Synthesis of 6 and 7. In order t o gain access t o the desired fullerenyne segments, we subjected 3b to the conditions of the oxidative Hay coupling13in acetone for 2 h a t 30 "C at relatively high concentration (ca. 0.3 mol/L). To our surprise we were able to detect the formation of a polymer (Scheme 2) after double precipitation from pentane/dichloromethane (80:20)in 68% which we unequivocally can assign structure 6 by NMR and IR spectroscopy (see Figure 4). The polymer 6 should consist of stereoisomers. The 13C NMR spectrum of 6 shows six broadened lines (five between 6 70 and 90; Table 1, Figure 4) indicating that the stereoisomers have very similar spectroscopic properties. Analytical GPC suggests that the number average degree of polymerization is ca. 38.14 The small amount of formed oligomeric material consisted of a mixture of different compounds which we have not been able to separate by chromatography. The mixture was sensitive and decomposed immediately under considerable darkening. We presume that these species are cyclic oligomers. (12)Nicolaou, K. C.; Dai, W.-M.Angew. Chem.,Znt.Ed. Engl. 1991, 30, 1387. Bergman, R. G. ACC.Chem. Res. 1973, 6, 25. (13)Hay, A. S. J.Org. Chem. 1960,27,3320. Glaser, C. Chem. Ber. 1669, 2, 422.
(14) Gel permeation chromatography of 6 was performed using polystyrene as standard. The obtained molecular weights were multiplied by the factor of 2.42 to correct for the different molecular weights of the two monomers: M , = 9300; M , = 15200;M J M , = 1.58.
I
l
220
l
I
l
200
I
l
180
l
160
I
I
140 PPM
/
120
l
I
100
I
I
80
I
I
60
Figure 4. 13C NMR spectrum of polymer 6 in CDC13.
Table 1.
Spectroscopic Data (6) for the Compounds 6 and 7
13C NMR
CD
end
inner
quaternary butadiyne C
co
73.36 75.73 222.49 80.96 87.50 83.82 7a 82.07 88.13 78.60 72.67 73.95 223.47 7b 82.10 88.33 80.86 86.91 78.14 84.35 71.91 72.57 222.63 75.29 75.82 223.47 7c 82.10 88.29 80.88 87.03 78.30 84.51 71.91 72.64 222.56 87.28 83.90 83.95 73.29 75.38 223.43 75.74 75.97 7d 82.09 88.34 80.81 87.06 78.20 83.98 71.87 72.60 223.43 87.35 87.44 84.44 73.20 73.30 222.55 75.36 75.71 75.79 75.94 7e 82.13 88.35 80.84 87.07 78.15 83.90 71.89 72.56 223.46 87.46 84.41 73.28 75.40 222.54 75.79 75.94 7f 82.13 88.36 80.84 87.07 78.16 83.96 71.89 72.59 222.52 87.46 84.43 73.29 75.40 223.47 75.71 75.81 75.94 6
Surprisingly the same experiment conducted at a much lower concentration of monomer did not seem to favor the formation of cycles either. In order to gain access to linear oligomers, we performed a co-oligomerization of 3b with ethynylcymantrene5J5(Scheme 3). Aqueous workup resulted in the isolation of a 85%yield of coupled products. TLC of the raw product with ethyl ether as eluent showed that a whole series of compounds 7 must have formed in this reaction. Repeated chromatography and preparative HPLC made 7a-f accessible in relatively low yields (7a,8.2%; b, 12.5%;c, 7.7%; d, 5.5%; e, 3.6%; f, 2.5%; C = 40%). While it was possible to purify 7a-d by chromatography over flash silica gel with 70:30 pentanelethyl ether, the higher oligomers had t o be separated by preparative HPLC. The low yields of the purified products in comparison to the 85% yield of the raw products is due t o heavy losses during chromatography. While in the case of 7a,b the occurrence of only one isomer is possible, the higher oligomers 7c-f should form mixtures of stereoisomers which we have been able to resolve neither by column chromatography nor by HPLC. The I3C NMR spectra of 7b-f do not show a split of the lines (Table 1);the same behavior is observed here as it is in polymer 6 (exception is observed in 7c),but some of the signals of the oligomers are considerably broadened (Table 1) indicating the (expected) formation of mixtures of stereoisomers. (15)Lo Sterzo, C.; Miller, M. M.; Stille, J. K. Organometallics 1989,
8, 2331.
~
2494 Organometallics, Vol. 14, No.5, 1995
Bunz et al.
Scheme 3
7b
Conclusions In conclusion we have been able to show that the facile preparation of the hitherto unknown tricarbonyl(diethynylcyclopentadieny1)manganese complexes 3 and 4 can be achieved utilizing Stille-Beletskaya methodology. Diethynyl3b can be used in a Hay-type reaction to either polymerize to 6 or by addition of an end capping reagent oligomerize this novel building block to 7a-f. The formed linear oligomers 7 represent tricarbonylmanganese-supportedlinear segments out of a hitherto unknown member of the fullerenyne family.
Experimental Section
7e
Ortho Metalation Experiment with TMEDA in Pentane at 78 "C. An amount of 2.00 g (6.66 mmol) of 1 in 50 mL of pentane is cooled to -78 "C; sec-BuLi (5.0 mL, 7.0 mmol) is added by syringe, and the formed solution is stirred for 5 min. A precooled solution of TMEDA (9.76 g, 84.0 mmol, -78 "C) in 20 mL of pentane is added slowly. The resulting solution is stirred for 1 h at -78 "C whereupon a thick suspension forms. To this suspension l,2-diiodoethane (2.11 g, 7.49 mmol) dissolved in the minimum amount of pentane is added quickly. Warming to 21 "C, aqueous workup, and filtration (flash silica gel, 3 cm x 2 cm, pentane) yields 1.56 g (55%)of ortho 2 which shows very broad resonances in the NMR and is used without further purification and characterization. Metalation Experiment in Ethyl Ether at -55 "C. An amount of 5.00 g (16.7 mmol) of 1 in 200 mL of ethyl ether is treated with 15.0 mL (21.0 mmol) sec-BuLi at -55 "C for 20 min. Diiodoethane (6.00 g, 21.3 mmol) in ca. 20 mL of ethyl ether is added. Workup (vide supra) yields 5.84 g (81%)of 2 as a yellow oil.
Ethyl ether and tetrahydrofuran (THF) were distilled from benzophenondpotassium under nitrogen. Dimethylfomamide was distilled from calcium hydride in uacuo. Pentane and methanol were used as received from Riedel de Haen. N,N,","-Tetramethylethylenediamine (TMEDA), l,2-diiodeTricarbonyl{ 1,2-bis[ (trimethylsilyl)ethynyl]cythane, triphenylarsine, PdC12(CH&N)2, tris(dibenzylidene1clopentadieny1)manganese (3a). An amount of 1.56 g (3.62 dipalladium, and sec-BuLi were purchased from Aldrich. mmol) ofortho 2, 1.60 g (6.13 mmol) of 5, and 20 mg (77 pmol) (Trimethylsilyl)(trimethylstannyl)acetylene (5) was prepared of PdC12(CH&N)2 are dissolved at -20 "C in 2 mL of DMF by deprotonation of (trimethylsily1)acetylenewith BuLi in ethyl and ca. 10 mL of ethyl ether. After removal of the cooling bath, ether and functionalization with trimethyltin chloride. All the reaction mixture is stirred for 0.5 h. An additional 20 mg reactions were carried out under an atmosphere of nitrogen (77 pmol) of catalyst is added at 21 "C, and the stirring is in flame-dried glassware using standard inert-gas and Schlenk continued for another 0.5 h. The solvent is removed at 0.1 techniques. lH NMR spectra are recorded at 300 MHz, and mm/Hg at 21 "C. Repeated chromatography of the residue I3C N M R spectra, at 75 MHz at ambient temperature. For (flash silica gel, 18 cm x 2 cm; 19:l pentane/dichloromethane) preparative HPLC a Gilson Abimed 305 with a Merck yields as first fraction 247 mg of 1 and as second fraction 821 LiCroSorb CN (10 pm) column (21 cm x 5 cm) was used with mg (57%,mp 82 "C) of sa. IR (KBr, cm-'1: v 3122,3114,2962, pure ethyl ether (Riedel de Haen, pa quality) as eluent (flow 2169, 2027, 1950, 1454. 'H NMR (CDC13): 6 0.24 (s, 18 H), rate 20 mumin). 4.56 (t, 1H, J = 2.8 Hz),4.91 (d, 2 H, J = 2.8 Hz).I3C NMR T r i c a r b o n y l [ ( ~ ~ e ~ ~ ~ y l ) e ~ ~ l ~ e t h y n y l (CDCl3): ) c y c l -6 -0.27, 80.33, 84.75, 86.20, 95.54, 97.75, 223.53. MS (EI; mlz (relative intensity)): 396 (M+,l%), 312 (M - 3C0, manganese (1). A 20.0 g (60.6 mmol) amount of iodocyman100%). Anal. Calcd: C, 54.52; H, 5.33. Found: C, 54.44; H, trene,Is 17.0 g (65.1 mmol) of 5, and 500 mg (1.93 m o l ) of 5.10. PdCl2(CH&N)2 are stirred at 0 "C in ca. 50 mL of DMF for 2 h. The reaction mixture is allowed t o warm to 21 "C and is Tricarbonyl{ 1,3-bis[(trimethylsilyl)ethynyl]cystirred at this temperature for another 14 h. Removal of DMF clopentadieny1)manganese (4a). An amount of 5.84 g (13.6 (oil pump vacuum, 21 "C) and sublimation of the dark residue mmol) of 2 (ortho-para mixture), 5.00 g (19.1 mmol) of 5, and (50 "ClO.05 mmHg) yields 13.7 g (75%,mp 55 "C) of 1 as yellow 2 x 90 mg (2 x 347 pmol) of PdClz(CH&N)2 in 5 mL of DMF crystals. IR (KBr, cm-'1: Y 3119,2963,2161,2025,1938,1468, and 25 mL of ethyl ether are treated as described for 3a. 1251. 'H (CDC13): 0.21 (s,9 H), 4.66 (t, J = 2.1 Hz; 2 H), 4.97 Repeated chromatography (vide supra; 20 cm x 4 cm) yields (t, J = 2.1 Hz; 2 HI. 13CNMR (CDC13): S 0.30, 81.92, 82.80, as first fraction a mixture of 4a and 1. Short path distillation 86.21, 94.88, 96.94, 224.01. MS (EI; mlz (relative intensity)): of this mixture leads to the isolation of 432 mg of 1 (80 "C1 300 (M+, 12%),244 (M+ - 2C0,20%), 216 (M+ - 3C0,100%). 0.01 mmHg) and 1.38 g (26%; 130-150 "C/O.Ol mmHg; mp 51 Anal. Calcd: C, 52.01; H, 4.36. Found: C, 52.05; H, 4.33. "C) of 4a as a light yellow solid. The second fraction of the
Organometallics,Vol.14,No.5, 1995 2495
(Diethynylcyclopentadieny1)tricarbonylmanganese chromatography yields 2.27 g (42%)of 3a. Data for 4a are as follows. IR (KBr, cm-'): v 3118,2968,2169,2020,1944,1250. 'H NMR (CDC13): 6 0.17 (s, 18 H), 4.85 (d, 2 H, J = 1.7 Hz), 5.14 (t, 1 H, J = 1.7 Hz). I3C NMR (CDCl3): 6 -0.33, 81.92, 85.19, 88.93, 95.28, 96.22, 223.47. MS (EI; mlz (relative intensity)): 396 (M+6%),340 (M - 2C0,20%),312 (M - 3C0, 80%). Anal. Calcd: C, 54.52; H, 5.34. Found: C, 54.72; H, 5.33. Tricarbonyl( 1,2-diethynylcyclopentadienyl)manganese (3b). An amount of 974 mg (2.44 mmol) of 3a and 500 mg (5.00 mmol) of KzC03 are dissolved in 20 mL of methanol, and the solution is stirred for 15 min. Partition between pentane and water yields 535 mg (87%; yellow powder, mp 51 "C) of analytically pure 3b. IR (KBr, cm-l): v 3294, 3136, 3112, 2123, 2019,1939,1913. 'H NMR (CDC13): 6 3.04 (s, 2 H), 4.62 (t, 1 H, J = 2.8 Hz), 4.98 (d, 2 H, J = 2.8 Hz). 13C NMR (CDC13): 6 74.60, 79.93, 80.58, 84.80, 85.63, 223.20. MS (FD; mlz): 252 (M+). Anal. Calcd: C, 57.17; H, 1.99. Found: C, 57.06; H, 1.94. TricarbonyU1,3-diethynylcyclopentadienyl)manganese (4b). An amount of 991 mg (2.49 mmol) of 4a is treated as described for 3b to give 543 mg (86%;yellow powder, mp 53 "C) of analytically pure 4b. IR (KBr, cm-'1: v 3300, 2124, 2028, 1937. 'H NMR (CDC13): 6 2.83 (s,2 H), 4.96 (d, 2H, J = 1.5 Hz), 5.29 (t, lH, J = 1.5 Hz). I3C NMR (CDCl3): 6 75.33, 77.56, 79.69, 85.83, 90.37, 223.12. Anal. Calcd: C, 57.17; H, 1.99. Found: C, 57.03; H, 1.78. Poly{tricarbonyl(1,2-diethyndiylcyclopentadienyl)manganese} (6). An amount of 1.12 g (4.44 mmol) of 3b,500 mg of CuCl (5.05 mmol), and 600 mg (5.16 mmol) of TMEDA are dissolved in ca. 50 mL of acetone, and the solution is warmed to 30 "C. Under stirring, oxygen is bubbled through the solution for 2.5 h. After removal of the acetone in uacuo the residue is dissolved in dichloromethane and washed thoroughly with water t o remove copper salts and amine. After evaporation of the solvent the crude product is dissolved in the minimum amount of dichloromethane and precipitated twice into a 85:15 mixture of pentane and dichloromethane to remove oligomers. Polymer 6 is isolated in 68%yield (767 mg) as a sensitive brownish film-forming and transparent material which decomposes in the laboratory atmosphere during several hours under darkening. IR (KBr, cm-l): v 3124,2227,2163, 2028, 1945, 1938. 'H NMR (CDC13j: 6 4.75 (bs, 2 Hj, 5.08 (bs, 1 H). Hay-Coupling of Ethynylcymantrene with 3b in Acetone. An amount of 1.62 g (6.42 mmol) of 3b,0.910 g (3.99 mmol) of ethynylcymantrene, 2.00 g (20.2 mmol) of CuC1, and 2.00 g (17.2mmol) of TMEDA in 100 mL of acetone are treated as described for the synthesis of 6 t o isolate 2.11 g (84%)of the crude coupling product. Chromatography over flash silica with a pentane/ethyl ether gradient (0%-100% ethyl ether) yields two fractions (I, 497 mg; 11, 1.05 g). MethanoUethyl ether (1:l)yields 558 mg of a third fraction. We were able t o separate 7a-d from fraction I after repeated chromatography (pentane/ethyl ether variable ratio) involving heavy losses. Fraction I1 was separated by preparative HPLC and shown to contain 7a-f. The HPLC-separated oligomers were dissolved in the minimum amount of dichloromethane and precipitated into pentane to remove traces of stabilizer added to the used eluent ethyl ether. The combined yields from I and I1 were as follows. 1,4-Bis(cymantrenyl)butadiyne(7a): 194 mg, 8.2%,retention time 16.1 min; mp 151 "C; lH NMR (CDC13) 6 4.10 (bs, 4 H), 5.11 (bs, 4 H).
(a-Cymantrenylbutadiynyl)-w-cyman~nyl[l9-cym~trenylene(4,l-butadiynediyl)] (7b): 306 mg, 12.5%,retention time 17.5 min; mp 169 "C; IR (KBr, cm-l) v 3124, 2226, 2162, 2024, 1940, 836; 'H NMR (CDCl3) 6 4.63 (bs, 1 H), 4.70 (bs, 4 H), 5.04 (bs, 2 H), 5.12 (bs, 4 H); MS (FD; mlz) 705 (M+). (a-Cymantrenylbutadiyny1)-w-cymantrenylbis[1,242~mantrenylene(4,l-butadiynediyl)] (7c): 192 mg, 7.7%, retention time 19.2 min; dec 115 "C; IR (KBr, cm-') v 3123, 2228,2162,2026, 1941, 848, 836; 'H NMR (CDCl3) 6 4.66 (bs, 2 H), 4.71 (bs, 4 H), 5.08 (m, 4 H), 5.12 (bs, 4 H); MS (FD; mlz) 955 (M+). (a-Cymantrenylbutadiynyl)-w-cymantrenyltris[l,2-cymantrenylene(4,l-butadiynediyl)](7d): 139 mg, 5.5%, retention time 20.5 min; dec 123 "C; IR (KBr, cm-l) v 3124, 2227,2162,2025,1939,848,834; 'H NMR (CDC13) 6 4.64 (bs, 3 H), 4.70 (bs, 4 H), 5.05 (bs, 2 H), 5.10 (bs, 4 HI, 5.13 (s, 4 H); MS (FD; mlz) 1205 (M+). (a-Cymantrenylbutadiyny1)-ocymantrenyltetrakis[l~-cyman~nylene(4,l-butadiynediyl)l Vel: 93 mg, 3.6%, retention time 22.5 min; 'H NMR (CDC13) 6 4.64 (bs, 4 H), 4.71 (bs, 4 H), 5.08 (bs, 12 H). (a-Cymantrenylbutadiyny1)-w-cymantrenylpentakis[l~cymantrenylene(4,l-butadiyne-diyl)l (70: 65 mg, 2.5%, retention time 25.0 min; lH NMR (CDCl3) 6 4.64 (bs, 5 H), 4.71 (bs, 4 H), 5.05 (bs, 2 H), 5.06 (bs, 8 H), 5.15 (bs, 4 H). Crystallographic Data for 3a. ClsHzlO~SizMn: M = 396.4; light yellow, air stable blocks (0.30 x 0.25 x 0.40 mm3); space group C2lc; a = 29.923(1),b = 15.9145(7),c = 9.327(1) A; a = 90, ,9 = 102.920(7),y = 90";V = 4329.1(6) A3;2 = 8; D, = 1.217 g cm-3; ,u = 61.65 cm-'; 3150 reflections, 2948 observed (F > 3dF)); R = 0.071, R, = 0.074. Crystallographic Data for 4a. C~HzlOsSizMn: M = 396.4; light yellow, air stable blocks (0.20 x 0.25 x 0.50 mm3); space group P212~21; a = 17.027(3), b = 12.339(4), c = 10.235(2) A; a = ,6 = y = 90"; V = 2150(1) A3; 2 = 4; D,= 1.225 g ~ m - p~ = ; 62.06 cm-l; 1585 reflections, 1392 observed (F > 3dF)); R = 0.059, R, = 0.058. Data collection was carried out in both cases at 298 K with a n Enraf-Nonius-CAD4 automatic diffractometer (Cu Ka radiation, , I= 1.5405 A). The structures were solved by the heavy atom method (Patterson), and the non-hydrogen atoms were refined anisotropically. Programs used were CRYSTALS and MOLEN. An empirical absorption correction was applied. Refinement was done by full matrix least squares analyses with anisotropic temperature factors for all non-hydrogen atoms. The hydrogen atoms were refined with fixed isotropic temperature factors in the riding mode.
Acknowledgment. U.H.F.B. is a Liebig scholar (1992-1994) and DFG scholar (1994-1996) and wishes to thank Prof. K. Mullen and Mrs. Addy Bunz for generous support and the Fonds der Chemischen Industrie, the Stiftung Volkswagenwerk, the Deutsche Forschungsgemeinschaft, and the BASF for financial aid. We thank also Jutta Wiegelmann for helpful discussions. Supplementary Material Available: Tables of crystallographic parameters, positional and thermal parameters, and bond distances and angles for 3a and 4a (11 pages). Ordering information is given on any current masthead page. OM940890P
