Article pubs.acs.org/Organometallics
Synthesis of Diruthenium Complexes Derived from PyridylSubstituted Indenes Dawei Gong,† Bowen Hu,† Jing Shi,† Peipei Ma,† Baiquan Wang,*,‡ and Dafa Chen*,†,‡ †
MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemical Engineering & Technology, Harbin Institute of Technology, Harbin 150001, People’s Republic of China ‡ State Key Laboratory of Elemento-Organic Chemistry, College of Chemistry, and Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Nankai University, Tianjin 300071, People’s Republic of China S Supporting Information *
ABSTRACT: Thermal treatment of the trinuclear ruthenium complex {μ2-η5:η1-(C5H4N)(C9H5)}Ru3(CO)9 (1) with 1,5-heptadiene, diallyl sulfide, 1,4-hexadiene, and 1,7-octadiene respectively generated the series of diruthenium products {(C5H4N)(μ2-η5,η1-C9H5CHCH2CH2R)}Ru2(CO)x (4, R = −CH2CHCHCH3; 6, R = SCH2CHCH2; 7, R = −CHCHCH3; 8, R = −(CH2)3CHCH2) via the insertion of an terminal CC bond into the Ru−C(η1) bond of 1. When 1 was treated with diallyl ether, the complex {(C5H4N)(μ2-η5,η3-C9H5CCH2CH2OCCHCH3)}Ru2(CO)4 (5) with a five-membered oxygencontaining heterocycle was produced. Reactions of 2-methyl-3-(2-pyridyl)indene or 2,5-dimethyl-3-(2-pyridyl)indene with Ru3(CO)12 gave the cycloruthenated complexes {(C5H4N)(μ2-η5,η1-RC9H4CH2)}Ru2(CO)5 (9, R = H; 10, R = CH3) with structures similar to those of 4, 7, and 8, via C(sp3)−H activation. The molecular structures of 5−7 and 10 were determined by X-ray diffraction.
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INTRODUCTION C−C bond formation through heteroatom-directed aromatic C−H/olefin coupling catalyzed by a transition metal is regarded as an atom-economical method1−3 and has been developed rapidly since the pioneering studies of Murai and coworkers.4 For example, many ruthenium catalysts have been applied for such transformations to introduce an alkenyl or alkyl group to the ortho position of an aromatic ring.2−4 Cycloruthenation via the activation of a C−H bond is believed to be the key step in these reactions. Thus, it is important to study the reactivity toward olefins of cycloruthenated compounds. Although migratory insertion of an olefin into an M−C bond is a classical reaction in organometallic chemistry, and it exists in several catalytic transformations, such as Ziegler−Natta polymerization and Heck reactions,5,6 examples of olefin insertion into a Ru−C bond in identified cycloruthenated compounds are rare.7,8 Pfeffer’s group found that olefins could insert into the Ru−C bond of (η6-C6H6)Ru(C6H4CH2NMe2)Cl or its derivatives.7 Kakiuchi, Chatani et al. synthesized (CH3COC6H4)Ru(PPh3)2H and its derivatives and studied their reactivity with 2-propenyl boronic ester to afford a series of C−C coupling products.8 These reactions gave deep insight into such C−H/olefin coupling reactions. We have synthesized the triruthenium carbonyl complex {μ2η5:η1-(C5H4N)(C9H5)}Ru3(CO)9 (1) from the reaction of Ru3(CO)12 with 3-(2-pyridyl)indene via C(sp2)−H activation. This complex contains a five-membered ruthenacycle, and a series of monoolefins and alkynes could insert into this ruthenacycle.9 Recently, we found that it could also react with 1,5-hexadiene to produce complex 2, which could further © XXXX American Chemical Society
convert to another new dinuclear ruthenium complex 3 through intramolecular carbometalation (Scheme 1).10 The Scheme 1. Reactivity of 1 with 1,5-Hexadiene
results might guide the development of heteroatom-directed intermolecular C−H/1,5-diene coupling reactions and suggested that the CC double bond is the second directing group in transition-metal-catalyzed heteroatom-directed intramolecular C−H/olefin coupling reactions.11 As an extension of our work, herein we report the reactivity of 1 with a series of dienes. Furthermore, we synthesized two new dinuclear cycloruthenated complexes by the reaction of Ru3(CO)12 with 3-(2-pyridyl)-2-methylindene or 2,5-dimethyl-3-(2pyridyl)indene via C(sp3)−H activation.
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RESULTS AND DISCUSSION Reactions of 1 with Dienes. First, we tried the reaction of 1 with 1,5-heptadiene in refluxing toluene, and the orange product {(C 5 H 4 N)(μ 2 -η 5 ,η 1 -C 9 H 5 CHCH 2 CH 2 CH 2 CH Received: January 11, 2017
A
DOI: 10.1021/acs.organomet.7b00021 Organometallics XXXX, XXX, XXX−XXX
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Organometallics CHCH3)}Ru2(CO)5 (4) was obtained (Scheme 2). The 1H NMR exhibits one multiplet at 5.46 ppm for the two alkenyl
ppm is shown, which means no noncoordinated CC bond exists. The IR spectrum shows four absorption bands at 2002, 1958, 1929, and 1905 cm−1 for its CO ligands. Single-crystal Xray diffraction analysis revealed that complex 5 is a dinuclear complex with a five-membered oxygen-containing heterocycle (Figure 1). The Ru(1)−Ru(2) distance (2.7848(7) Å) is close
Scheme 2. Reactivity of 1 with 1,5-Heptadiene
protons, one characteristic singlet at 5.10 ppm for the Cp proton, and one triplet at 2.72 ppm for the Ru−CH proton.12 The multiplet at 5.46 ppm suggests that the remaining CC bond does not coordinate with any ruthenium atom, because coordination would result in a significant upfield chemical shift.10 The IR spectrum of 4 in CH2Cl2 shows five absorption bands at 2064, 1999, 1979, 1961, and 1907 cm−1 for its CO ligands. From the 1H NMR and IR results, 4 is assigned as a dinuclear ruthenium complex via the insertion of the terminal CC bond into the Ru−C(η1) bond of complex 1. A possible reaction mechanism is proposed in Scheme 3. After the coordination with one of the ruthenium atoms, the Figure 1. Solid-state structure of 5. The thermal ellipsoids are displayed at 50% probability. Hydrogen atoms have been omitted for clarity. Selected bond distances (Å) and angle (deg): Ru(1)−Ru(2), 2.7848(7); Ru(2)−N(1), 2.217(3); Ru(2)−C(19), 2.237(4); Ru(2)− C(22), 2.233(4); Ru(2)−C(24), 2.207(4); C(19)−C(22), 1.432(5); C(22)−C(24), 1.404(6); C(18)−C(19)−Ru(2), 91.6(2).
Scheme 3. Proposed Formation Mechanism of 4
to that of 3 (2.8344(11) Å).10 The Ru(2) is coordinated to the C19−C22−C24 fragment in an η3 mode. The C(19)−C(22) (1.432(5) Å) and C(22)−C(24) (1.404(6) Å) distances are in the range of CC bond distances. A proposed formation mechanism of 5 is shown in Scheme 5. The initial steps were similar to those shown in Scheme 3, and the intermediate A was formed. After the CC bond coordination, allylic C−H bond activation, and hydride transfer, D was generated. D then underwent CC insertion, β-H cleavage, and allylic C−H activation, giving the final product 5. The process from D to 5 is similar to that from 2 to 3,10 and it is also related to heteroatom-directed intramolecular C−H/ olefin coupling reactions, suggesting the CC bond acts as a secondary directing group.11 It should be noted that the internal CC bond in D is more electron rich than that in 4 because of the electron-donating property of the adjacent oxygen atom, and this may be the reason it could coordinate with ruthenium. The reaction of 1 with diallyl sulfide was also tested, and the complex {(C5H4N)(μ3-η5,η1,η1-C9H5CHCH2CH2SCH2CH CH2)}Ru2(CO)4 (6) was prepared (Scheme 6). 1H NMR exhibits a singlet at 4.76 ppm for the Cp proton. Similar to the case for 4, the multiplets at 5.80 and 5.32 ppm also indicate the existence of one noncoordinated CC bond.12 The IR spectrum shows four absorption bands at 2006, 1950, 1933, and 1869 cm−1 for its CO ligands. The single-crystal structure revealed that complex 6 is a dinuclear tetracarbonyl complex, with the sulfur atom coordinating with Ru (Figure 2). The coordination ability of sulfur is stronger than that of oxygen, resulting in the different reactivities of diallyl sulfide and diallyl ether with 1.
terminal CC bond inserted into the Ru−C(η1) bond, forming an intermediate with a new Ru−C(η1) bond. This intermediate then underwent β-H cleavage and hydride transfer to form product 4. The mechanism is similar to that of 1 with monoolefins.9a Unlike complex 2 shown in Scheme 1, the −CH3 group prevents the coordination of the internal CC bond with the Ru atom in 4. When 1 was treated with diallyl ether, the complex {(C5H4N)(μ2-η5,η3-C9H5CCH2CH2OCCHCH3)}Ru2(CO)4 (5) was produced (Scheme 4). The 1H NMR exhibits a singlet at 4.39 ppm for the Cp proton.12 No signal between 5 and 7 Scheme 4. Reactivity of 1 with Diallyl Ether
B
DOI: 10.1021/acs.organomet.7b00021 Organometallics XXXX, XXX, XXX−XXX
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Organometallics Scheme 5. Proposed Formation Mechanism of 5
During the reaction of 1 with diallyl ether to form 5, there was a double-bond-migration process (B to D in Scheme 5). Therefore, we also tested the reactions of 1 with 1,4-hexadiene and 1,7-octadiene, respectively (Scheme 7). The products
Scheme 6. Reactivity of 1 with Diallyl Sulfide
Scheme 7. Reactivity of 1 with 1,4-Hexadiene or 1,7Octadiene
{(C 5 H 4 N)(μ 2 -η 5 ,η 1 -C 9 H 5 CHCH 2 CH 2 CHCHCH 3 )}Ru2(CO)5 (7) and {(C5H4N)(μ2-η5,η1-C9H5CH(CH2)5CH CH2)}Ru2(CO)5 (8) were generated, respectively. Their 1H NMR and IR spectra are quite similar to that of 4. The 1H NMR signals of alkenyl protons (5.50 ppm for 7; 5.47 ppm for 8) reveal the noncoordinate CC bonds. The results indicate that only one terminal CC bond participated in each reaction process, and no CC bond migration occurred. The structure of 7 was further confirmed by single-crystal X-ray diffraction analysis (Figure 3). The Ru(1)−Ru(2) distance (2.7959(4) Å) is slightly longer than that of 5 (2.7848(7) Å) but shorter than that of 6 (2.8269(3) Å). Reactions of 2-Methyl-3-(2-pyridyl)indene or 2,5Dimethyl-3-(2-pyridyl)indene with Ru3(CO)12. Complex 1 was formed by the reaction of Ru3(CO)12 with 3-(2pyridyl)indene via C(sp2)−H activation, and this complex exhibited many interesting reactions with alkynes, monoolefins, and dienes, which gave important insight into related C−C coupling reactions.9,10 In comparison to C(sp2)−H activation, C(sp3)−H activation is normally more difficult because of its inherently low reactivity.13,14 We also wanted to synthesize some ruthenium complexes via C(sp3)−H activation and hoped
Figure 2. Solid-state structure of 6. The thermal ellipsoids are displayed at 30% probability. Hydrogen atoms have been omitted for clarity. Selected bond distances (Å) and angle (deg): Ru(1)−Ru(2), 2.8269(3); Ru(2)−N(1), 2.135(2); Ru(2)−C(15), 2.167(3); Ru(2)− S(1), 2.3392(8); C(19)−C(20), 1.282(5); C(1)−C(15)−Ru(2), 94.90(17). C
DOI: 10.1021/acs.organomet.7b00021 Organometallics XXXX, XXX, XXX−XXX
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Organometallics
Figure 4. Solid-state structure of 10. The thermal ellipsoids are displayed at 30% probability. Hydrogen atoms have been omitted for clarity. Selected bond distances (Å) and angle (deg): Ru(1)−Ru(2), 2.7963(5); Ru(2)−N(1), 2.169(2); Ru(2)−C(16), 2.157(3); C(7)− C(16)−Ru(2), 95.32(17).
Figure 3. Solid-state structure of 7. The thermal ellipsoids are displayed at 30% probability. Hydrogen atoms have been omitted for clarity. Selected bond distances (Å) and angle (deg): Ru(1)−Ru(2), 2.7959(4); Ru(2)−N(1), 2.176(3); Ru(2)−C(15), 2.197(3); C(18)− C(19), 1.237(6); C(14)−C(15)−Ru(2), 92.6(2).
distance (2.7963(5) Å) is also close to that of 7 (2.7959(4) Å). In principle, cycloruthenation via the activation of the sp2 C(13)−H bond should also give a six-membered ring; however, no such product was found in both cases shown in Scheme 8.16 We then tried the reactions of 9 or 10 with olefins and alkynes, while no reactivity was found. This is not unexpected because, as discussed above, 9 and 10 are more similar to olefin insertion products of 1 (for instance: 4, 7, and 8) than to 1 itself, and these six-membered ruthenacycle products could no longer react with olefins and alkynes.
that these complexes would show reactivity similar to that of 1. To achieve this goal, 2-methyl-3-(2-pyridyl)indene was first chosen as a ligand precursor. A new route was developed to synthesize this compound by the reaction of 3-(2-pyridyl)indene with NBS and CH3MgBr in turn, and the total yield was 33%, much higher than that reported in the literature (10%) (Scheme 8).15 Different from the case for 3-(2-pyridyl)indene, the reaction of 2-methyl-3-(2-pyridyl)indene with Ru3(CO)12 generated the dinuclear ruthenium complex {(C5H4N)(μ2η5,η1-C9H5CH2)}Ru2(CO)5 (9) via C(sp3)−H activation. The 1 H NMR of 9 exhibits a singlet at 5.08 ppm for the Cp proton and two doublets at 2.26 and 1.97 ppm for the Ru−CH2 protons.12 The IR spectrum shows five absorption bands at 2066, 1999, 1982, 1962, and 1909 cm−1 for its CO ligands, quite similar to those of 4, 7, and 8. The reaction of 2,5-dimethyl-3-(2-pyridyl)indene with Ru3(CO)12 afforded the similar complex {(C5H4N)(μ2-η5,η1CH3C9H4CH2)}Ru2(CO)5 (10) (Scheme 8). The 1H NMR of 10 exhibits a singlet at 5.03 ppm for the Cp proton and two doublets at 2.24 and 1.94 ppm for the Ru−CH2 protons. The IR spectrum also shows five absorptions for its CO ligands. A single-crystal structure further confirmed it is a dinuclear complex with the six-membered ruthenacycle Ru(2)−N(1)− C(5)−C(6)−C(7)−C(16)−Ru(2) (Figure 4). In fact, the structure of 10 is quite similar to that of 7: both are dinuclear complexes and contain a {(C5H4N)(μ2-η5,η1-Ind-C)}Ru2(CO)5 fragment with a six-membered ruthenacycle (Ru(2)−N(1)− C(5)−C(6)−C(7)−C(16)−Ru(2) for 10 and Ru(2)−N(1)− C(5)−C(6)−C(14)−C(15)−Ru(2) for 7). The Ru(1)−Ru(2)
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SUMMARY AND CONCLUSIONS In conclusion, reactions of triruthenium complex 1 with a series of dienes were studied. For most dienes, only one terminal C C bond was reactive and inserted into the Ru−C(η1) bond to generate the series of dinuclear products 4 and 6−8. However, for diallyl ether, complex 5 with a five-membered oxygencontaining heterocycle was obtained. This complex was formed through 1,1-insertion of the first CC bond, double-bond migration of the second CC bond, and intramolecular carbometalation. The results further suggest that the CC double bond can act as the second directing group in transitionmetal-catalyzed heteroatom-directed intramolecular C−H/ olefin coupling reactions and may also provide guidance for developing heteroatom-directed intermolecular C−H/diallyl ether coupling reactions for the construction of five-membered oxygen-containing heterocycles. Furthermore, reactions of 2methyl-3-(2-pyridyl)indene/2,5-dimethyl-3-(2-pyridyl)indene with Ru3(CO)12 were studied, and the two cycloruthenated diruthenium products 9 and 10 were obtained via regioselective
Scheme 8. Synthesis and Reactivity of 2-Methyl-3-(2-pyridyl)indene and 2,5-Dimethyl-3-(2-pyridyl)indene
D
DOI: 10.1021/acs.organomet.7b00021 Organometallics XXXX, XXX, XXX−XXX
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Organometallics C(sp3)−H activation, which have structures similar to those of complexes 4 and 6−8. This gives a new route to synthesize such diruthenium complexes by direct cycloruthenation via C(sp3)−H activation.
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Synthesis of 2-Bromo-5-methyl-3-(2-pyridyl)indene. By using a similar procedure as described for 2-bromo-3-(2-pyridyl)indene, 2bromo-5-methyl-3-(2-pyridyl)indene was obtained in 90% yield as white solid. 1H NMR (400 MHz, CDCl3):δ 8.81 (d, J = 4.8 Hz, 1H, Py-H) [7.83 (t, J = 8.0 Hz, 1H), 7.72 (d, J = 8.0 Hz, 1H), 7.37 (s, 1H), 7.32 (m, 2H), 7.04 (d, J = 8.0 Hz, 1H) (Py-H and Ar-H)], 3.77 (s, 2H, Cp-H), 2.37 (s, 3H, CH3). 13C NMR (100 MHz, CDCl3, ppm): 153.1, 149.5, 143.3, 141.3, 139.0, 136.4, 126.1, 124.7, 123.7, 122.9, 122.6, 121.3, 45.7, 21.5. HR-MS (ESI): calcd for C15H12BrN + H, 286.0231; found, 286.0233. Synthesis of 2,5-Dimethyl-3-(2-pyridyl)indene. By using a procedure similar to that described for 2-methyl-3-(2-pyridyl)indene, 2,5-dimethyl-3-(2-pyridyl)indene was obtained in 78% yield as a light yellow solid. 1H NMR (400 MHz, CDCl3):δ 8.86 (d, J = 4.4 Hz, 1H, Py-H) [7.77 (t, J = 8.0 Hz, 1H), 7.43 (d, J = 8.0 Hz, 1H), 7.29 (d, J = 8.0 Hz, 1H), 7.24 (m, 2H), 6.97 (d, J = 8.0 Hz, 1H) (Py-H and ArH)], 3.44 (s, 2H, Cp-H), 2.35 (s, 3H, CH3), 2.23 (s, 3H, CH3). 13C NMR (100 MHz, CDCl3, ppm): 155.0, 149.6, 145.4, 144.0, 139.2, 137.7, 136.2, 135.7, 124.9, 124.2, 122.9, 121.6, 120.4, 43.2, 21.6, 15.2. HR-MS (ESI): calcd for C16H15N + H, 222.1282; found, 222.1282. Synthesis of Complex 4. A solution of 0.200 g (0.27 mmol) of 1 and 0.265 g (2.7 mmol) of 1,5-heptadiene in 10 mL of toluene was refluxed for 12 h. The solvent was removed under reduced pressure, and the residue was placed in an Al2O3 column. Elution with EtOAc/ petroleum ether gave 0.070 g (41%) of 4 as orange crystals. 1H NMR (400 MHz, CDCl3): δ 8.34 (d, J = 5.6 Hz, 1H, Py-H) [7.74 (t, J = 8.0 Hz, 1H), 7.60 (d, J = 8.0 Hz, 1H), 7.53 (d, J = 8.0 Hz, 1H), 7.36 (d, J = 8.0 Hz, 1H), 7.26 (m, 1H), 7.15 (t, J = 8.0 Hz, 1H), 7.06 (t, J = 5.6 Hz, 1H) (Py-H and Ar-H)], 5.46 (m, 2H, CHCH), 5.10 (s, 1H, CpH), 2.72 (t, J = 8.0 Hz, 1H, Ru-CH), 2.19−1.68 (m, 6H, CH2CH2CH2), 1.65 (d, J = 4.0 Hz, 3H, CH3). 13C NMR (100 MHz, CDCl3, ppm): 206.3, 204.1, 198.9, 196.9, 187.3, 157.2, 153.3, 137.8, 125.6, 122.2, 122.0, 121.0, 120.5, 116.1, 111.1, 107.8, 101.8, 78.0, 70.3, 65.2, 62.5, 34.4, 14.2, 11.6. IR (νCO, cm−1, CH2Cl2): 2064 (s), 1999 (s), 1979 (s), 1961 (m), 1907 (s). Anal. Calcd for C26H21NO5Ru2: C, 49.6; H, 3.4; N, 2.2. Found: C, 49.7; H, 3.5; N, 2.1. Synthesis of Complex 5. By using a procedure similar to that described above, reaction of 0.200 g (0.27 mmol) of 1 and 0.265 g (2.7 mmol) of diallyl ether in 10 mL of toluene generated 0.034 g of complex 5 in 21% yield as orange crystals. 1H NMR (400 MHz, CDCl3): δ 8.53 (d, J = 5.6 Hz, 1H, Py-H) [7.74 (t, J = 8.0 Hz, 1H), 7.57 (d, J = 8.0 Hz, 1H), 7.46 (d, J = 8.0 Hz, 1H), 7.32 (d, J = 8.0 Hz, 1H), 7.22 (t, J = 8.0 Hz, 1H), 7.11 (t, J = 8.0 Hz, 1H), 7.04 (t, J = 5.6 Hz, 1H) (Py-H and Ar-H)], 4.64 (dt, J = 2.4, 5.6 Hz, 1H, CH2CH2), 4.45 (m, 1H, CH2CH2), 4.39 (s, 1H, Cp-H), 3.39 (q, J = 5.6 Hz, 1H, CHMe) [2.98 (m, 1H), 2.07 (m, 1H) (CH2CH2)], 1.50 (d, J = 5.6 Hz, 3H, CH3). 13C NMR (100 MHz, CDCl3, ppm): 208.1, 205.1, 203.0, 192.2, 156.5, 155.1, 136.6, 125.4, 122.0, 121.1, 121.0, 120.2, 116.7, 109.8, 101.1, 94.5, 80.3, 73.8, 61.4, 36.7, 33.7, 24.7, 19.5. IR (νCO, cm−1, CH2Cl2): 2002 (s), 1958 (s), 1929 (m), 1905 (s). Anal. Calcd for C24H17NO5Ru2: C, 47.9; H, 2.9; N, 2.3. Found: C, 48.0; H, 3.0; N, 2.2. Synthesis of Complex 6. By using a procedure similar to that described above, reaction of 0.200 g (0.27 mmol) of 1 and 0.308 g (2.7 mmol) of diallyl sulfide in 10 mL of toluene generated 0.150 g of complex 6 in 89% yield as orange crystals. 1H NMR (400 MHz, CDCl3): δ 8.41 (d, J = 5.2 Hz, 1H, Py-H) [7.61 (t, J = 8.0 Hz, 1H), 7.52 (d, J = 8.0 Hz, 1H), 7.39 (d, J = 8.0 Hz, 1H), 7.28 (m, 1H), 7.16 (t, J = 8.0 Hz, 1H), 7.08 (t, J = 8.0 Hz, 1H), 6.94 (t, J = 5.2 Hz, 1H) (Py-H and Ar-H)], [5.80 (m, 1H), 5.32 (m, 2H) (CH2CH)], 4.76 (s, 1H, Cp-H) [3.57 (d, J = 5.6 Hz, 1H), 3.13−3.07 (m, 2H), 2.85 (dd, J = 6.4, 14 Hz, 1H), 2.73 (dt, J = 5.2, 14 Hz, 1H), 2.61 (dd, J = 4.8, 14 Hz, 1H), 2.18 (m, 1H) (RuCHCH2CH2SCH2)]. 13C NMR (100 MHz, CDCl3, ppm): 206.7, 204.4, 199.2, 187.8, 157.4, 153.3, 137.6, 135.5, 124.9, 121.8, 120.8, 120.5, 114.6, 111.5, 106.2, 103.1, 77.5, 62.3, 21.4, 20.0, 8.9. IR (νCO, cm−1, KBr): 2006 (s), 1950 (s), 1933 (s), 1869 (s). Anal. Calcd for C24H19NO4Ru2S: C, 46.5; H, 3.1; N, 2.3. Found: C, 46.2; H, 3.3; N, 2.2. Synthesis of Complex 7. By using a procedure similar to that described above, reaction of 0.200 g (0.27 mmol) of 1 and 0.227 g (2.7
EXPERIMENTAL SECTION
General Considerations. All manipulations were carried out under an inert N2(g) atmosphere using a Schlenk line. Solvents were distilled from appropriate drying agents under N2 before use. All reagents were purchased from commercial sources. Liquid compounds were degassed by standard freeze−pump−thaw procedures prior to use. The 1H NMR spectra were recorded on a Bruker Avance 400 spectrometer. 1H NMR chemical shifts were referenced to residual solvent as determined relative to Me4Si (δ 0 ppm). IR spectra were recorded on a Nicolet iS5 FT-IR spectrometer. Elemental analyses were performed on a PerkinElmer 240C analyzer. Complex 1 was prepared as described previously.9a Synthesis of 2-Bromo-3-(2-pyridyl)indene. A solution of 3.00 g (15.5 mmol) of 3-(2-pyridyl)indene and 2.75 g (15.5 mmol) of NBS in 50 mL of CHCl3 was refluxed for 1 h. The solvent was removed under reduced pressure, and to the residue were added EtOAc (50 mL) and H2O (50 mL), respectively. The aqueous phase was extracted with EtOAc (30 mL × 3). The combined organic phase was dried with Na2SO4. After concentration, the residue was placed on a silica gel column. Elution with EtOAc/petroleum ether gave 3.70 g (88%) of 2bromo-3-(2-pyridyl)indene as a white solid. 1H NMR (400 MHz, CDCl3): δ 8.80 (d, J = 2.8 Hz, 1H, Py-H) [7.84 (t, J = 8.0 Hz, 1H), 7.74 (d, J = 8.0 Hz, 1H), 7.57 (d, J = 8.0 Hz, 1H), 7.43 (d, J = 8.0 Hz, 1H), 7.33 (d, J = 5.2 Hz, 1H), 7.26 (m, 2H) (Py-H and Ar-H)], 3.82 (s, 2H, CH2). 13C NMR (100 MHz, CDCl3, ppm): 152.8, 149.4, 143.1, 141.8, 141.2, 136.3, 126.6, 125.2, 124.6, 123.5, 123.1, 122.6, 120.8, 46.0. HR-MS (ESI): calcd for C14H10BrN+H, 272.0075; Found, 272.0077. Synthesis of 2-Methyl-3-(2-pyridyl)indene. A solution of 7.70 g (28.4 mmol) of 2-bromo-3-(2-pyridyl)indene and 0.127 g (0.568 mmol) of Pd(OAc)2 in 50 mL THF was added 9.98 mL (3M, 29.9 mmol) of CH3MgBr drop by drop. The resulting solution was left for 12 h at room temperature, followed by adding H2O slowly. The resulting solution was extracted by EtOAc (30 mL × 4). The combined organic phase was dried with Na2SO4. After concentrated, the residue was placed in silica gel column. Elution with EtOAc/ petroleum ether to give 2.20 g (37%) of 2-methyl-3-(2-pyridyl)indene as a yellow oil. The 1H NMR and 13C NMR spectra are consistent with that reported in the literature.15 Synthesis of 5-Methyl-3-(2-pyridyl)indene. This complex was synthesized similar to the procedure to synthesize 3-(2-pyridyl)indene as described in the literature.17 A solution of 12.8 g (81.0 mmol) of 2bromopyridine in 50 mL of diethyl ether was added dropwise at −60 °C to 48.0 mL (81.0 mmol) of n-butyllithium (1.6 M in n-hexane). The resulting reaction mixture was stirred for 20 min at this temperature. Thereafter, 11.8 g (81.0 mmol) of 6-methyl-1-indanone dissolved in 70 mL of diethyl ether was added to the stirred solution within 20 min. After a reaction time of 2 h at −40 to −60 °C, the solution was left at room temperature for 2 h. The reaction was then hydrolyzed with 50 mL of saturated ammonium chloride solution. After extraction with EtOAc (50 mL × 4), the combined organic phase was concentrated, and the residue was treated at 0 °C dropwise with 100 mL of sulfuric acid (85%). The dark red solution was stirred for 2 h at this temperature and then poured into 150 g of ice. The resulting reaction mixture was neutralized with solid sodium hydroxide and then washed with diethyl ether. After organic workup and recrystallization, 11.7 g (70%) of light yellow oil 5-methyl-3-(2-pyridyl)indene was obtained. 1H NMR (400 MHz, CDCl3):δ 8.81 (d, J = 4.8 Hz, 1H, PyH) [8.10 (s, 1H), 7.70 (m, 2H), 7.47 (d, J = 8.0 Hz, 1H), 7.24 (m, 1H), 7.18 (d, J = 8.0 Hz, 1H), 6.98 (t, J = 6.0 Hz, 1H) (Py-H and ArH)], 3.54 (d, J = 8.0 Hz, 2H, Cp-H), 2.54 (s, 3H, CH3). 13C NMR (100 MHz, CDCl3, ppm): 154.8, 149.0, 143.7, 142.8, 141.4, 135.9, 135.4, 133.7, 125.6, 123.2, 122.4, 121.7, 121.7, 37.5, 21.4. HR-MS (ESI): calcd for C15H13N+H, 208.1126; Found, 208.1125. E
DOI: 10.1021/acs.organomet.7b00021 Organometallics XXXX, XXX, XXX−XXX
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Organometallics Table 1. Crystal Data and Summary of X-ray Data Collection for 5−7 and 10 formula fw T, K radiation (λ, Å) cryst syst space group a, Å b, Å c, Å α, deg β, deg γ, deg V, Å3 Z Dcalc, g cm−3 μ, mm−1 F(000) cryst size, mm 2θ range, deg no. of rflns collected no. of indep rflns/Rint no. of params goodness of fit on F2 R1, wR2 (I > 2σ(I)) R1, wR2 (all data)
5
6
7
10
C24H17NO5Ru2 601.53 113(2) Mo Kα (0.71073) monoclinic P21/n 8.0115(16) 15.292(3) 17.322(4) 90 102.42(3) 90 2072.5(7) 4 1.928 1.496 1184 0.16 × 0.14 × 0.10 1.80−25.02 15154 3669/0.0596 290 1.018 0.0321, 0.0671 0.0446, 0.0727
C24H19NO4Ru2S 619.60 293(2) Mo Kα (0.71073) monoclinic P21/c 13.9658(3) 9.8578(2) 17.6649(3) 90 106.671(2) 90 2329.74(8) 4 1.767 1.416 1224 0.7 × 0.6 × 0.5 3.6740−28.4920 9684 4100/0.0223 289 1.103 0.0263, 0.0554 0.0347, 0.0603
C25H19NO5Ru2 615.55 293(2) Mo Kα (0.71073) triclinic P1̅ 8.5870(4) 10.6283(5) 13.9652(7) 109.174(4) 101.890(4) 91.156(4) 1172.67(10) 2 1.743 1.324 608 0.1 × 0.08 × 0.06 2.98−25.00 8794 4128/0.0261 298 1.039 0.0307, 0.0625 0.0431, 0.0702
C21H13NO5Ru2 561.46 296(2) Mo Kα (0.71073) orthorhombic Pbcn 15.946(3) 16.474(3) 15.387(3) 90 90 90 4042.2(13) 8 1.845 1.526 2192 0.32 × 0.30 × 0.26 2.22−28.33 34947 5039/0.0287 263 1.088 0.0282, 0.0330 0.0694, 0.0730
mmol) of 1,4-hexadiene in 10 mL of toluene generated 0.130 g of 7 in 78% yield as orange crystals. 1H NMR (400 MHz, CDCl3): δ 8.34 (d, J = 5.2 Hz, 1H, Py-H) [7.74 (t, J = 8.0 Hz, 1H), 7.60 (d, J = 8.0 Hz, 1H), 7.54 (d, J = 8.0 Hz, 1H), 7.36 (d, J = 8.0 Hz, 1H), 7.26 (m, 1H), 7.16 (t, J = 8.0 Hz, 1H), 7.06 (t, J = 8.0 Hz, 1H) (Py-H and Ar-H)], 5.50 (m, 2H, CHCH), 5.11 (s, 1H, Cp-H), 2.73 (t, J = 8.0 Hz, 1H, Ru-CH) [2.40 (m, 1H), 2.44−2.23 (m, 1H), 2.10−2.01 (m, 2H) (CH2CH2)], 1.65 (d, J = 4.0 Hz, 3H, CH3). 13C NMR (100 MHz, CDCl3, ppm): 206.4, 204.3, 198.9, 196.9, 187.6, 157.1, 153.2, 137.8, 130.1, 125.5, 124.1, 122.2, 122.0, 121.0, 120.5, 116.1, 111.1, 107.8, 101.7, 78.0, 62.4, 35.1, 33.4, 17.0. IR (νCO, cm−1, CH2Cl2): 2064 (s), 1999 (s), 1979 (s), 1962 (m), 1908 (s). Anal. Calcd for C25H19NO5Ru2: C, 48.8; H, 3.1; N, 2.3; Found: C, 48.9; H, 3.2; N, 2.3. Synthesis of Complex 8. By using a similar procedure as described above, reaction of 0.200 g (0.27 mmol) of 1 and 0.297 g (2.7 mmol) of 1,7-octadiene in 10 mL toluene generated 0.120 g of 7 in 69% yield as orange crystals. 1H NMR (400 MHz, CDCl3):δ 8.36 (d, J = 5.2 Hz, 1H, Py-H) [7.76 (t, J = 8.0 Hz, 1H), 7.63 (d, J = 8.0 Hz, 1H), 7.56 (d, J = 8.0 Hz, 1H), 7.39 (d, J = 8.0 Hz, 1H), 7.26 (m, 1H), 7.19 (t, J = 8.0 Hz, 1H), 7.08 (t, J = 5.2 Hz, 1H) (Py-H and Ar-H)], 5.47 (m, 3H, CHCH2), 5.13 (s, 1H, Cp-H), 2.76 (t, J = 8.0 Hz, 1H, Ru-CH), 2.16−0.87 (m, 10H, (CH2)5). 13C NMR (100 MHz, CDCl3, ppm): 210.4, 205.9, 203.6, 197.4, 186.6, 157.4, 153.4, 138.0, 125.7, 122.5, 121.6, 121.4, 120.0, 116.1, 110.7, 108.5, 103.1, 79.1, 65.2, 43.8, 35.2, 30.5, 28.7, 13.8, 6.7. IR (νCO, cm−1, CH2Cl2): 2063 (s), 1999 (s), 1979 (s), 1962 (m), 1908 (m). Anal. Calcd for C27H23NO5Ru2: C, 50.4; H, 3.6; N, 2.2. Found: C, 50.7; H, 3.7; N, 2.2. Synthesis of Complex 9. A solution of 0.200 g (0.31 mmol) of Ru3(CO)12 and 0.193 g (0.93 mmol) of 2-methyl-3-(2-pyridyl)indene in 20 mL of toluene was refluxed for 3 h. The solvent was removed under reduced pressure, and the residue was placed on an Al2O3 column. Elution with EtOAc/petroleum ether gave 0.143 g (56%) of 9 as an orange solid. 1H NMR (400 MHz, CDCl3): δ 8.36 (d, J = 5.6 Hz, 1H, Py-H) [7.75 (t, J = 8.0 Hz, 1H), 7.55 (m, 2H), 7.36 (d, J = 8.0 Hz, 1H), 7.23 (d, J = 8.0 Hz, 1H), 7.14 (t, J = 8.0 Hz, 1H), 7.07 (t, J = 5.6 Hz, 1H) (Py-H and Ar-H)], 5.08 (s, 1H, Cp-H), 2.26 (d, J = 8.0 Hz, 1H, Ru-CH2), 1.97 (d, J = 8.0 Hz, 1H, Ru-CH2). 13C NMR (100 MHz, CDCl3, ppm): 207.6, 205.1, 200.1, 198.1, 187.9, 158.2, 154.5, 138.8,
126.5, 123.2, 122.8, 122.1, 121.5, 117.7, 109.3, 109.2, 103.2, 80.5, 66.0. IR (νCO, cm−1, CH2Cl2): 2066 (s), 1999 (s), 1982 (s), 1962 (m), 1909 (m). Anal. Calcd for C20H11NO5Ru2: C, 43.9; H, 2.0; N, 2.6. Found: C, 44.2; H, 2.1; N, 2.4. Synthesis of Complex 10. By using a procedure similar to that described above, reaction of 0.200 g (0.31 mmol) of Ru3(CO)12 and 0.206 g (0.93 mmol) of 2,5-dimethyl-3-(2-pyridyl)indene in 20 mL of toluene generated 0.167 g of 10 in 64% yield as orange crystals. 1H NMR (400 MHz, CDCl3): δ 8.35 (d, J = 5.6 Hz, 1H, Py-H) [7.74 (t, J = 8.0 Hz, 1H), 7.54 (d, J = 8.0 Hz, 1H), 7.46 (d, J = 8.0 Hz, 1H), 7.08 (s, 1H), 7.05 (t, J = 8.0 Hz, 1H), 6.99 (d, J = 8.0 Hz, 1H) (Py-H and Ar-H)], 5.03 (s, 1H, Cp-H), 2.41 (s, 3H, Me), 2.24 (d, J = 8.0 Hz, 1H, Ru-CH2), 1.94 (d, J = 8.0 Hz, 1H, Ru-CH2). 13C NMR (100 MHz, CDCl3, ppm): 206.8, 204.2, 199.3, 197.1, 186.9, 157.3, 153.4, 137.6, 135.4, 124.9, 121.6, 120.9, 120.5, 114.5, 107.4, 106.4, 103.4, 79.1, 64.7, 21.3. IR (νCO, cm−1, CH2Cl2): 2066 (s), 2000 (s), 1983 (s), 1963 (m), 1909 (m). Anal. Calcd for C21H13NO5Ru2: C, 44.9; H, 2.3; N, 2.5. Found: C, 45.1; H, 2.4; N, 2.4. Crystallographic Studies. Single crystals of complexes 5−7 and 10 suitable for X-ray diffraction were obtained from hexane/CH2Cl2 solution. X-ray diffraction studies were carried out with a Rigaku Saturn or SuperNova X-ray single-crystal diffractometer. Data collections were performed using four-circle κ diffractometers equipped with CCD detectors. Data were reduced and then corrected for absorption.18 Solution, refinement, and geometrical calculations for all crystal structures were performed with SHELXTL.19 The crystal data and summary of X-ray data collection are given in Table 1.
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ASSOCIATED CONTENT
* Supporting Information S
The Supporting Information is available free of charge on the ACS Publications Web site. The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.organomet.7b00021. IR and NMR spectra of the new compounds (PDF) Crystallographic data for complexes 5−7 and 10 (CIF) F
DOI: 10.1021/acs.organomet.7b00021 Organometallics XXXX, XXX, XXX−XXX
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AUTHOR INFORMATION
Corresponding Authors
*E-mail for B.W.:
[email protected]. *E-mail for D.C.:
[email protected]. ORCID
Dafa Chen: 0000-0002-7650-4024 Notes
The authors declare no competing financial interest.
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ACKNOWLEDGMENTS This work was supported by the National Natural Science Foundation of China (Nos. 21672045, 21302028, 21372122, and 21201049) and the China Postdoctoral Science Foundation (No. 2016M591519).
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