JP4680519B2 - Method for producing imidazole carbene metal complex - Google Patents

Description

The present invention relates to a method for producing an imidazole carbene transition metal complex which can be produced under mild conditions without using a base and the like, is excellent in reproducibility, and contains a large amount of metal as a complex formation target.

The production examples of metal complexes coordinated with carbene originated in the work of Wanzlick and Ofele et al. In 1968, and many reports have been made by Lappert et al. In the 1970s and 1980s. Since the carbene itself was isolated and identified by Arduengo et al. In 1991, more active research has been developed. Since these carbenes are singlet carbenes having a loan pair electron on carbon, they can be treated in the same way as phosphines that are trivalent phosphorus compounds, and metal complexes used as supporting ligands instead of phosphines. Research has started. Compared to phosphine complexes, metal complexes using carbene have revealed many advantages, such as an improvement in reaction activity.

These carbenes are divalent carbon species but can be isolated, so Arduengo
Although it was named “Stable Carbene”, it was extremely difficult to handle because of its high reactivity with oxygen and water. Therefore, a production method has been developed in which a carbene is generated in a reaction system by treating a salt, which is a precursor in the production of a carbene complex, with a suitable base, and is directly applied to the production of a metal complex. However, it has gradually become clear that the base for generating carbene reacts with the metal complex precursor and the desired metal complex cannot be obtained. .

A method for producing a carbene metal complex to solve this problem is to use the carbene as it is for the production of a complex, as in the production of a phosphine complex. Therefore, research on compounds that can be equivalent to carbene ligands has long been developed. Lappert et al. Have reported the production of carbene complexes by cleavage of double bonds from enetramine compounds called electron-rich olefins. However, in the carbene complex production in this method, since a high temperature condition is required to generate a carbene by cleaving a carbon-carbon double bond, the starting complex or the target complex may cause decomposition. It was.

In view of this background, research has been conducted on stable carbene equivalents that can easily generate carbene without using a base under mild conditions. Grubbs et al. Have reported a method for converting to an carbene complex using an alcohol adduct or chloroform adduct derived from an imidazolinium salt. These adducts can generate carbene species under mild conditions, and their usefulness as carbene equivalents have been reported.

However, for imidazol-2-ylidene derived from imidazolium salts, Wan
Only carbene complex production by carbene transfer from silver-carbene complexes using silver oxide reported by g and Lin has been reported.

Wang, H.M.J.Wang, I.J.B.Lin, Organometallics, (USA), American Chemical Society, 1998, Vol. 17, p. 972-975 Shawl, Dig, Lee, Grubs (M. Scholl, S. Ding, CWLee, RHGrubbs), Organic Letters, (USA), American Chemical Society, 1999, Volume 1, p. 953-956

When preparing a carbene metal complex as described above, it is necessary to treat the imidazolium salt with an appropriate base, and even those that do not require a base can cleave the carbon-carbon double bond in the enetramine compound to cleave the carbene. It required high temperature to generate.

Therefore, an object of the present invention is to provide a production method for giving an imidazole carbene metal complex under mild conditions without using a base or the like.

The method for producing an imidazole carbene metal complex represented by the general formula (3) of the present invention is characterized by using an imidazole carbene adduct represented by the general formula (1) and a metal complex represented by the general formula (2). To do.

[In the formula, n is an integer of 1 to 3, and R ¹ is a monovalent to trivalent alkyl group having 1 to 50 carbon atoms, and a monovalent to trivalent group having 1 to 50 carbon atoms. Selected from the group consisting of alkenyl groups, monovalent to trivalent alkynyl groups having 1 to 50 carbon atoms, and monovalent to trivalent aryl groups having 1 to 30 carbon atoms. Groups may include cyclic, acyclic, straight chain and / or branched groups, and at least one hydrogen may be exchanged with a functional group.
R ² is an alkyl group having 1 to 50 carbon atoms, an alkenyl group having 1 to 50 carbon atoms, an alkynyl group having 1 to 50 carbon atoms, and an aryl having 1 to 30 carbon atoms Selected from the group consisting of groups, these substituents may include cyclic, acyclic, linear and / or branched groups and at least one hydrogen may be replaced with a functional group .
R ³ and R ⁴ are the same or different and are each hydrogen, halogen, nitro group, nitroso group, alkoxyl group, aryloxy group, amide group, carboxyl group, carbonyl group, thio group, sulfonyl group, 1 to 50 carbons Selected from the group consisting of alkyl groups having atoms, alkenyl groups having 1 to 50 carbon atoms, alkynyl groups having 1 to 50 carbon atoms, and aryl groups having 1 to 30 carbon atoms, and The substituent of is cyclic,
Acyclic, straight chain and / or branched groups may be included and at least one hydrogen may be exchanged with a functional group.
E is a group 13 element such as B or Al, R ⁵ is an alkyl group having 1 to 20 carbon atoms,
Selected from the group consisting of aryl and alkoxyl groups, and at least one of these
One hydrogen may be substituted with an alkoxyl group, and n ′ is an integer of 1 to 4. ]

[Wherein M is a transition metal element of group 6 to 10 and is a low valence (0 to 3) transition metal element, and L is a monodentate or multidentate charged or charged coordinated to the central metal. There are no multiple ligands. ]

[In the formula, n is an integer of 1 to 3, and R ¹ is a monovalent to trivalent alkyl group having 1 to 50 carbon atoms, and a monovalent to trivalent group having 1 to 50 carbon atoms. Selected from the group consisting of alkenyl groups, monovalent to trivalent alkynyl groups having 1 to 50 carbon atoms, and monovalent to trivalent aryl groups having 1 to 30 carbon atoms. Groups may include cyclic, acyclic, straight chain and / or branched groups, and at least one hydrogen may be exchanged with a functional group.
R ² is an alkyl group having 1 to 50 carbon atoms, an alkenyl group having 1 to 50 carbon atoms, an alkynyl group having 1 to 50 carbon atoms, and an aryl having 1 to 30 carbon atoms Selected from the group consisting of groups, these substituents may include cyclic, acyclic, linear and / or branched groups and at least one hydrogen may be replaced with a functional group .
R ³ and R ⁴ are the same or different and are each hydrogen, halogen, nitro group, nitroso group, alkoxyl group, aryloxy group, amide group, carboxyl group, carbonyl group, thio group, sulfonyl group, 1 to 50 carbons Selected from the group consisting of alkyl groups having atoms, alkenyl groups having 1 to 50 carbon atoms, alkynyl groups having 1 to 50 carbon atoms, and aryl groups having 1 to 30 carbon atoms, and The substituents may include cyclic, acyclic, straight chain and / or branched groups, and at least one hydrogen may be replaced with a functional group.
M is a transition metal element of group 6 to 10 and is a low valence (0 to 3 valence) transition metal element, and L is a monodentate or multidentate charged or uncharged plural coordinated to the central metal. It is a ligand. ]
Examples of the functional group in the general formula (1) and the general formula (3) include halogen, nitro group, nitroso group, alkoxyl group, aryloxy group, amide group, carboxyl group, carbonyl group, thio group, and sulfonyl group.

According to the present invention, an imidazole carbene transition metal complex can be produced under mild conditions without using a base or the like.

  Hereinafter, the present invention will be described in more detail with reference to examples.

All experiments were performed under an argon atmosphere or under vacuum conditions. All imidazolium carbene adducts were used under vacuum for about 30 minutes immediately before the reaction. THF and toluene were dried using sodium benzophenone. Other solvents were distilled using an appropriate desiccant. In addition, a commercially available product was obtained and used as it was.

[Example 1]
Synthesis of Mo (CO) ₅ ( ⁱ Pr-imidazole carbene) complex

In a Schlenk flask, 93 mg (0.37 mmol) of ⁱ Pr-imidazole carbene-BEt ₃ and 98 mg of Mo (CO) ₆
mg (0.37 mmol) was weighed and 10 ml of toluene was added using a syringe. Thereafter, a Liebig condenser was attached and heated to reflux for 2 hours. The color of the solution changed from pale yellow to brownish yellow. After allowing to cool to room temperature, the solvent was distilled off under reduced pressure, washed with hexane, and then vacuum dried to obtain the target complex as a light brown solid. Yield 112 mg (0.29 mmol, 78% yield).

¹ H NMR (in CDCl ₃ ) δ 1.44 (d, J = 6.8 Hz, 12H, ⁱ Pr—CH ₃ ), 5.19 (sept, J = 6.8 Hz, 2H, ⁱ Pr—CH), 7.04 (s, 2H, CH = CH). ¹³ C { ¹ H} NMR (in C ₆ D ₆ ) δ 23.5 ( ⁱ Pr—CH ₃ ), 53.3 ( ⁱ Pr—CH), 118.0 (CH═CH), 184.0 (br) , NCN), 206.6 (cis-CO), 212.1 (trans-CO). IR (KBr): νCO; 1971, 1925, 1909, 1888 cm ⁻¹ . Anal. _{Calcd for C 14 H 16 MoN 2} O 5. C: 43.31, H: 4.15, N: 7.22. Found. C: 43.39, H: 4.40, N: 7.28.

From the above, the structure of the Mo (CO) ₅ ( ⁱ Pr-imidazole carbene) complex was determined.

[Example 2]
Synthesis of Mo (CO) ₅ (Mes-imidazole carbene) complex

In a Schlenk flask, add 220 mg (0.55 mmol) of Mes-imidazole carbene-BEt ₃ and 1 Mo (CO) ₆
42 mg (0.54 mmol) was weighed and 15 ml of toluene was added. The mixture was heated to reflux for 3 hours. Thereafter, the target complex was obtained as a light brown solid by the same operation as the synthesis of the Mo (CO) ₅ ( ⁱ Pr-imidazole carbene) complex. Yield 194 mg (0.36 mmol, 67% yield).

¹ H NMR (in CDCl ₃ ) δ 2.08 (s, 12H, Mes-o-CH ₃ ), 2.36 (s, 6H, Mes-p-CH ₃ ), 7.03 (s, 4H, Mes -M-H), 7.05 (s, 2H, CH = CH). ¹³ C { ¹ H} NMR (in CDCl ₃ ) δ 17.7 (Mes-o-CH ₃ ), 21.2 (Mes-p-CH ₃ ), 123.4 (CH═CH), 129.3 135.4, 137.7, 139.5 (Mes-Ph), 193.2 (br, NCN), 205.0 (cis-CO), 211.1 (trans-CO). IR (KBr) νCO; 1972, 1915, 1877 cm ⁻¹ . Anal. Calcd for C ₂₆ H ₂₄ MoN ₂ O ₅ C: 57.78, H: 4.48, N: 5.18. Found. C: 57.66, H: 4.49, N: 5.28.

As described above, the structure of the Mo (CO) ₅ (Mes-imidazole carbene) complex was determined.

[Example 3]
Synthesis of [Mo (η ³ -allyl) (amidinato) (CO) ₂ ( ⁱ Pr-imidazol carbene)] complex

First, the [Mo (η ³ -allyl) Cl (CO) ₂ (pyridine) ₂ ] complex was converted from the literature (DJ Bevan, RJ Mawby, J
Chem. Soc., Dalton Trans. (1980) 1904) (pre-precursor synthesis), [Mo (η ³ -allyl) (amidinato) (CO) ₂ ( ⁱ Pr-imidazole carbene) ] [Mo (
[eta] ^3- allyl) (amidinato) (CO) ₂ (pyridine)] complex was synthesized as follows.

After a solution of [Mo (η ³ -allyl) Cl (CO) ₂ (pyridine) ₂ ] complex (295 mg, 0.76 mmol) in THF (10 ml) was cooled to −78 ° C., formamidine (N (C ₆ H ₅ ) = C (H) N (H) C ₆ H ₅ , 150 mg, 0.67 mmol) and ⁿ BuLi (1.50 mol dm ^-3 in hexane, 0.52 ml, 0.78 mmol) and Li [(PhN) ₂ CH The mixture was heated to room temperature with stirring. After stirring for several hours, the solvent was distilled off under reduced pressure and washed several times with hexane. The residue was extracted with toluene, and the solvent was distilled off under reduced pressure to obtain the target complex [Mo (η ³ -allyl) (amidinato) (CO) ₂ (pyridine)] as a yellow powder (325 mg, 0.70 mmol, 92% yield). This complex could be obtained as yellow crystals containing 0.25 molecules of toluene by recrystallization from toluene / hexane.

IR (KBr): ν (CO) 1928, 1913, 1829 cm ⁻¹ . ¹ H NMR (toluene-d ₈ , at 30 ° C.): δ 1.46 (d, J = 9.2 Hz, 2H, allyl-C H ₂ ), 3.52 (br, 2H, allyl-C H ₂ ) , 3.70 (tt, J = 9.6, 6.6 Hz, 1H, allyl-C H ), 6.14 (m, 2H, m-C ₅ H ₅ N), 6.54 (m, 1H, _{p-C 5 H 5 N)} , 7.02 (m, 10H, C 6 H 5), 8.26 (s, 1H, amidinato-C H), 8.34 (d, J = 4.0Hz, 2H _{, o-C 5 H 5 N} ). (Toluene-d ₈ , at 60 ° C.): δ 1.44 (d, J = 9.6 Hz, 2H, allyl-C H ₂ ), 3.47 (d, J = 6.3 Hz, 2H, allyl-C _{H 2), 3.70 (tt,} J = 9.6,6.6Hz, 1H, allyl-C H), 6.23 (t, J = 6.6Hz, 2H, m-C 5 H 5 N) _{, 6.64 (t, J = 7.6Hz} , 1H, p-C 5 H 5 N), 7.00 (m, 10H, C 6 H 5), 8.26 (s, 1H, amidinato-C H ), 8.35 (d, J = 4.9 Hz, 2H, o-C ₅ H ₅ N). (Toluene-d ₈ , at −60 ° C.): δ 1.59 (d, J = 9.9 Hz, 2H, allyl-C H ₂ ), 3.65 (tt, J = 9.6, 6.6 Hz, 1H, allyl-C H ), 3.85 (d, J = 6.6 Hz, 2H, allyl-C H ₂ ), 5.84 (t, J = 6.9 Hz, 2H, m-C ₅ H ₅ N ), 6.15 (t, J = 7.6 Hz, 1 H, p-C ₅ H ₅ N), 7.07 (m, 10 H , C ₆ H ₅ ), 8.44 (s, 1 H, amidinato-C H), 8.45 (d, J = 5.9Hz, 2H, o-C 5 H 5 N). _{^{13 C {1 H} NMR (}} CDCl 3, at 55 ℃): δ 57.7 (s, allyl- C H 2), 75.7 (s, allyl- C H), 118.2,122.0, _{129.4,146.8 (s, C 6 H 5} ), 124.5,137.5,151.2 (s, C 5 H 5 N), 156.2 (s, amidinato- C H), 227 .9 (s, C 2 O). Anal. _{Calcd for C 23 H 21 MoN 3} O 2 · 0.25C 7 H 8: C, 60.62; H, 4.73; N, 8.57. Found: C, 60.40; H, 5.02; N, 8.75.

As described above, the structure of [Mo (η ³ -allyl) (amidinato) (CO) ₂ (pyridine)] was determined.

[Mo (η ³ -allyl) (amidinato) (CO) ₂ (pyridine)] (57 mg, 0.12 mmol) and ⁱ Pr-imidazole carbene · BEt ₃ (38 mg, 0.15 mmol) obtained by the above in a Schlenk flask Was measured, toluene (5 ml) was added, and the mixture was heated under reflux for 3 hours. After leaving to cool to room temperature, the solvent was distilled off under reduced pressure, washed with hexane (3 x 5 ml), and then vacuum dried to obtain the target complex [Mo (η ³ -allyl) (amidinato) (CO) ₂ ( ⁱ Pr-imidazol carbene)] complex was obtained as a yellow powder (62 mg, 0.11 mmol, 92% yield). Since the title compound could be recrystallized from CH ₂ Cl _{2, a} single crystal could be obtained, and its structure was confirmed by X-ray structural analysis.

¹ H NMR (in CDCl ₃ ) δ 0.99 (br, 12H, ⁱ Pr—CH ₃ ), 1.70 (d, J = 9.9 Hz, 2H, allyl-CH ₂ ), 4.09 (m, 1H, allyl-CH), 4.17 (d, J = 7.3 Hz, 2H, allyl-CH ₂ ), 4.58 (sept, J = 6.6 Hz, 2H, ⁱ Pr—CH), 6.85 ˜7.25 (m, 12H, Ph and HC═CH), 8.73 (s, 1H, amidinato-CH). ¹³ C { ¹ H} NMR (in CDCl ₃ , at 55 ° C.) δ 23.7 ( ⁱ Pr—CH ₃ ), 52.3 ( ⁱ Pr—CH), 60.6 (allyl-CH ₂ ), 86. 1 (allyl-CH), 117.4 (CH = CH), 117.8, 121.1, 129.1, 147.4 (Ph), 153.9 (amidinato-NCN), 189.4 (carbene- NCN), 228.6 (CO). IR (KBr) νCO; 1913, 1829 cm ⁻¹ . Anal. _{Calcd for C 27 H 32 MoN 4} O 2. C, 60.00; H, 5.97; N, 10.37. Found. C, 59.68; H, 6.12; N, 10.1.

The structure of the [Mo (η ³ -allyl) (amidinato) (CO) ₂ ( ⁱ Pr-imidazole carbene)] complex was determined as described above.

[Example 4]
Synthesis of [W (η ³ -allyl) (amidinato) (CO) ₂ ( ⁱ Pr-imidazolcarbene)] complex

First, the [W (η ³ -allyl) Cl (CO) ₂ (pyridine) ₂ ] complex is described in the literature (DJ Bevan, RJ Mawby, J.
Chem. Soc., Dalton Trans. (1980) 1904). (Pre-precursor synthesis)
, [W (η ³ -allyl) (amidinato) (CO) ₂ ( ⁱ Pr-imidazol carbene)] complex precursor [W (η ³
-allyl) (amidinato) (CO) ₂ (pyridine)] complex was synthesized as follows.
[W (η ³ -allyl) (amidinato) (CO) ₂ (pyridine)] complex is represented by [W (η ³ -allyl) Cl (CO) ₂ (pyridine) ₂
] Complex (805 mg, 1.70 mmol) and formamidine (N (C ₆ H ₅ ) = C (H) N (H) C ₆ H ₅ , 335 mg, 1.71 m
mol) and ⁿ BuLi (1.30 mol dm ^-3 in hexane, 1.4 ml, 1.82 mmol)
N) ₂ CH] was synthesized by the same method as in the case of the molybdenum complex. As a result, the target complex was obtained as a yellow powder (618 mg, 1.11 mmol, yield 65%). This complex could be obtained as yellow crystals containing 0.25 molecules of toluene by recrystallization from toluene / hexane.

IR (KBr): ν (CO) 1919, 1905, 1816 cm ⁻¹ . ¹ H NMR (toluene-d ₈ , at 27 ° C.): δ 1.82 (d, J = 7.3 Hz, 2H, allyl-C H ₂ ), 2.90 (tt, J = 9.2, 6. 6 Hz, 1H, allyl-C H ), 3.44 (br, 2H, allyl-C H ₂ ), 6.10 (m, 2H, m-C ₅ H ₅ N), 6.50 (t, J = _{7.6Hz, 1H, p-C 5} H 5 N), 7.01 (m, 10H, C 6 H 5), 8.35 (br, 2H, o-C 5 H 5 N), 8.89 ( br, 1H, amidinato-C H ). (Toluene-d ₈ , at 70 ° C.): δ 1.77 (d, J = 8.9 Hz, 2H, allyl-C H ₂ ), 2.89 (tt, J = 8.9, 6.6 Hz, 1H) , Allyl-C H ), 3.33 (d, J = 6.3 Hz, 2H, allyl-C H ₂ ), 6.22 (t, J = 7.3 Hz, 2H, m-C ₅ H ₅ N) , 6.63 (t, J = 7.6 Hz, 1H, p-C ₅ H ₅ N), 7.00 (m, 10H, C ₆ H ₅ ), 8.37 (d, J = 5.3 Hz, _{2H, o-C 5 H 5} N), 8.88 (s, 1H, amidinato-C H). (Toluene-d ₈ , at −45 ° C.): δ 1.99 (d, J = 9.2 Hz, 2H, allyl-C H ₂ ), 2.88 (tt, J = 8.9, 6.9 Hz, 1H, allyl-C H ), 3.74 (d, J = 6.6 Hz, 2H, allyl-C H ₂ ), 5.85 (t, J = 7.3 Hz, 2H, m-C ₅ H ₅ N ), 6.17 (t, J = 7.9 Hz, 1H, p-C ₅ H ₅ N), 7.04 (m, 10 H , C ₆ H ₅ ), 8.42 (d, J = 5.3 Hz) , 2H, o-C ₅ H ₅ N), 9.05 (s, 1H, amidinato-C H ). _{^{13 C {1 H} NMR (}} C 6 D 6, at 75 ℃): δ 50.0 (s, allyl- C H 2), 68.6 (s, allyl- C H), 118.7,122. _{9,129.7,146.2 (s, C 6 H 5} ), 124.5,137.1,151.0 (s, C 5 H 5 N), 156.7 (s, amidinato- C H) 220.9 (s, C 2 O). Anal. _{Calcd for C 23 H 21 N 3} O 2 W · 0.25C 7 H 8: C, 51.40; H, 4.01; N, 7.27. Found: C, 51.27; H, 4.09; N, 7.19.

The structure of the [W (η ³ -allyl) (amidinato) (CO) ₂ (pyridine)] complex was determined as described above.

[W (η ³ -allyl) (amidinato) (CO) ₂ (pyridine)] obtained by Schlenk flask as above
(72 mg, 0.13 mmol) and ⁱ Pr-imidazole carbene · BEt ₃ (35 mg, 0.14 mmol) were weighed, toluene (10 ml) was added, and the mixture was heated to reflux for 4 hours. After allowing to cool to room temperature, the solvent was distilled off under reduced pressure, washed with hexane (3 × 5 ml), and then vacuum dried to obtain the target complex [W (η ³ -allyl) (amidinato) (CO) ₂ ( ⁱ Pr-imidazol carbene)] complex was obtained as a yellow powder (76 mg, 0.12 mmol, 92% yield).

¹ H NMR (in CDCl ₃ , at 50 ° C.) δ 0.99 (br, 12H, ⁱ Pr—CH ₃ ), 1.88 (d, J = 9.9 Hz, 2H, allyl-CH ₂ ), 3. 18 (tt, J = 9.9, 6.6 Hz, 1H, allyl-CH), 4.13 (d, J = 6.6 Hz, 2H, allyl-CH ₂ ), 4.61 (sept, J = 6 .6 Hz, 2H, ⁱ Pr-CH), 6.87-7.25 (m, 12H, Ph and HC = CH), 9.33 (s, 1H, amidinato-CH). ¹³ C { ¹ H} NMR (in CDCl ₃ , at 55 ° C.) δ 23.3 ( ⁱ Pr—CH ₃ ), 52.6 ( ⁱ Pr—CH), 53.1 (allyl-CH ₂ ), 80. 3 (allyl-CH), 117.4 (CH = CH), 117.8, 121.6, 129.1, 146.2 (Ph), 154.3 (amidinato-NCN), 191.3 (carbene- NCN), 220.7 (CO). IR (KBr) νCO; 1904, 1818 cm ⁻¹ . Anal. _{Calcd for C 27 H 32 N 4} O 2 W. C, 51.60; H, 5.13; N, 8.92. Found. C, 51.89; H, 4.95; N, 9.07.

The structure of the [W (η ³ -allyl) (amidinato) (CO) ₂ ( ⁱ Pr-imidazole carbene)] complex was determined as described above.

[Example 5]
Synthesis of Mo (CO) ₄ (xylyl bridged bidentate imidazole carbene) complex

In a Schlenk flask, 162 mg (0.3 t) of xylyl-bridged bidentate imidazole carbene (BEt ₃ ) ₂ was added.
5 mmol) and 91 mg (0.34 mmol) of Mo (CO) ₆ and weigh about 10 ml of heptane at -78 ° C under vacuum.
added. After raising the temperature to room temperature, a Liebig condenser was attached and heated to reflux for 6 hours.
After completion of the reaction, the mixture was allowed to cool to room temperature, the colorless supernatant was removed, washed with hexane (3 × 10 ml), and then vacuum dried to obtain the target complex as a yellow powder. Yield 138 mg (0.29 m
mol, 84% yield).

¹ H NMR (in CDCl ₃ ): δ 4.09 (s, 6H, NCH ₃ ), 4.48 (d, J = 14.5 Hz, 2H, NCH ₂ Ar), 5.72 (d, J = 14 .5 Hz, 2H, NCH ₂ Ar), 6.62 (d, J = 1.3 Hz, 2H, HC = CH), 6.87 (d, J = 1.3 Hz, 2H, HC = CH), 7. 33 (m, 4H, Ar-H). (In DMSO-d ₆ ): δ 3.96 (s, 6H, NCH ₃ ), 4.71 (d, J = 13.9 Hz, 2H, NCH ₂ Ar), 5.42 (d, J = 13. 9 Hz, 2H, NCH ₂ Ar), 6.90 (d, J = 1.3 Hz, 2H, HC = CH), 7.29 (d, J = 1.3 Hz, 2H, HC = CH), 7.34 (M, 2H, Ar-H), 7.48 (m, 2H, Ar-H). ¹³ C { ¹ H} NMR (in DMSO-d ₆ ): δ 51.5 (NCH ₂ Ar), 120.1, 124.1, 128.2, 131.1, 136.3 (HC = CH and Ar ), 191.5 (NCN), 210.3 (CO), 218.8 (C)
. The signal attributed to the methyl carbon of NCH ₃ seemed to overlap with the solvent signal and could not be confirmed. IR (KBr) νCO; 1999, 1932, 1896, 1847, 1788 cm ⁻¹ . Anal. _{Calcd for C 20 H 18 MoN 4} O 4. C, 50.64; H, 3.83; N, 11.81. Found. C, 50.86; H, 4.02; N, 11.66.

The structure of the Mo (CO) ₄ (xylyl bridged bidentate imidazole carbene) complex was determined as described above.

[Example 6]
ⁱ Synthesis of Pr-imidazolecarbene and BH ₃ complexes

In a Schlenk flask, weigh 155 mg (0.62 mmol) of ⁱ Pr-imidazole carbene · BEt ₃ ,
About 10 ml of THF was added at -78 ° C under vacuum. After heating to room temperature, BH ₃ • THF complex (1.07 M
0.60 ml (0.64 mmol) of THF solution was added, and the mixture was stirred at room temperature for 1 hour. The reaction solution changed from pale yellow to colorless and transparent. Then, the solvent was distilled off under reduced pressure, and the target compound was obtained as a white solid by washing with pentane. Yield 32 mg (0.19 mmol, 31% yield). Although the reaction progressed quantitatively, the yield decreased because the product was soluble in pentane.

¹ H NMR (in C ₆ D ₆ ) δ 0.93 (d, J = 7.3 Hz, 12H, ⁱ Pr—CH ₃ ), 2.11 (q, J = 87.7 Hz, 3H, BH ₃ ) 5 .26 (sept, J = 6.6 Hz, 2H, ⁱ Pr-CH), 6.17 (s, 2H, CH = CH). ¹³ C { ¹ H} NMR (in C ₆ D ₆ ) δ 22.2 ( ⁱ Pr—CH ₃ ), 49.1 ( ⁱ Pr—CH), 114.5 (CH═CH). A signal attributed to the carbene carbon could not be confirmed. ¹¹ B NMR (in C ₆ D ₆ ) δ-36.4 (q, J = 88.0 Hz, BH ₃ ). IR (KBr): 3125, 2979, 2386, 2291, 2224, 1442, 1227, 1213. Anal. _{Calcd for C 9 H 19 BN 2} : C, 65.09; H, 11.53; N, 16.87. Found: C, 64.86; H, 11.94; N, 16.59.

As described above, the structure of the ⁱ Pr-imidazole carbene / BH ₃ complex was determined.

[Example 7]
Synthesis of Mes-imidazole carbene and BH ₃ complex

Mes-imidazole carbene ・ BEt ₃ 76 mg (0.19 mmol) and BH ₃・ THF complex 0.18 ml (0.19 mmol)
Were stirred in THF (ca. 10 ml) for 1 h at room temperature. Then ⁱ Pr-Imidazolecarbene / BH
_The target compound was isolated as a white solid by the same operation as in the synthesis of the _3- adduct. Yield 73 mg (0
.18 mmol, 93% yield).

^{_{1 H NMR (in C 6 D}} 6) δ 2.05 (s, 12H, Mes-o-CH 3), 2.09 (s, 6H, Mes-p-CH 3), 5.99 (s, 2H , CH = CH), 6.74 (s, 4H, Mes-m-H). No signal attributed to BH ₃ could be observed. ¹¹ B NMR (in C ₆ D ₆ ) δ-36.8 (q, J = 88.0 Hz, BH ₃ ).

The structure of the Mes-imidazole carbene / BH ₃ complex was determined as described above.

This compound is a known compound in the literature. T. Ramnial, H. Jong, ID McKenzie, M. Jennin
gs, JAC Clyburne, Chem. Commun., 2003, 1722.

DISCUSSION As is clear from the above examples, it has been found that according to the production method of the present invention, a carbene complex can be synthesized without using a base such as KO ^t Bu and under mild conditions.

Claims (2)

An imidazole carbene adduct represented by the general formula (1);

[In the formula, n is an integer of 1 to 3, and R ¹ is a monovalent to trivalent alkyl group having 1 to 50 carbon atoms, and a monovalent to trivalent group having 1 to 50 carbon atoms. Selected from the group consisting of alkenyl groups, monovalent to trivalent alkynyl groups having 1 to 50 carbon atoms, and monovalent to trivalent aryl groups having 1 to 30 carbon atoms. Groups may include cyclic, acyclic, straight chain and / or branched groups, and at least one hydrogen may be exchanged with a functional group.
R ² is an alkyl group having 1 to 50 carbon atoms, an alkenyl group having 1 to 50 carbon atoms, an alkynyl group having 1 to 50 carbon atoms, and an aryl having 1 to 30 carbon atoms Selected from the group consisting of groups, these substituents may include cyclic, acyclic, linear and / or branched groups and at least one hydrogen may be replaced with a functional group .
R ³ and R ⁴ are the same or different and are each hydrogen, halogen, nitro group, nitroso group, alkoxyl group, aryloxy group, amide group, carboxyl group, carbonyl group, thio group, sulfonyl group, 1 to 50 carbons Selected from the group consisting of alkyl groups having atoms, alkenyl groups having 1 to 50 carbon atoms, alkynyl groups having 1 to 50 carbon atoms, and aryl groups having 1 to 30 carbon atoms, and The substituents may include cyclic, acyclic, straight chain and / or branched groups, and at least one hydrogen may be replaced with a functional group.
E is a Group 13 element, R ⁵ is selected from the group consisting of an alkyl group having 1 to 20 carbon atoms, an aryl group, and an alkoxyl group, and at least one of these hydrogens is substituted with an alkoxyl group. N ′ is an integer from 1 to 4. ]
Using a metal complex represented by the general formula (2),

[Wherein M is a transition metal element of group 6 to 10 and is a low valence (0 to 3) transition metal element, and L is a monodentate or multidentate charged or charged coordinated to the central metal. There are no multiple ligands. ]
The manufacturing method of the imidazole carbene metal complex shown by General formula (3).

[In the formula, n is an integer of 1 to 3, and R ¹ is a monovalent to trivalent alkyl group having 1 to 50 carbon atoms, and a monovalent to trivalent group having 1 to 50 carbon atoms. Selected from the group consisting of alkenyl groups, monovalent to trivalent alkynyl groups having 1 to 50 carbon atoms, and monovalent to trivalent aryl groups having 1 to 30 carbon atoms. Groups may include cyclic, acyclic, straight chain and / or branched groups, and at least one hydrogen may be exchanged with a functional group.
R ² is an alkyl group having 1 to 50 carbon atoms, an alkenyl group having 1 to 50 carbon atoms, an alkynyl group having 1 to 50 carbon atoms, and an aryl having 1 to 30 carbon atoms Selected from the group consisting of groups, these substituents may include cyclic, acyclic, linear and / or branched groups and at least one hydrogen may be replaced with a functional group .
R ³ and R ⁴ are the same or different and are each hydrogen, halogen, nitro group, nitroso group, alkoxyl group, aryloxy group, amide group, carboxyl group, carbonyl group, thio group, sulfonyl group, 1 to 50 carbons Selected from the group consisting of alkyl groups having atoms, alkenyl groups having 1 to 50 carbon atoms, alkynyl groups having 1 to 50 carbon atoms, and aryl groups having 1 to 30 carbon atoms, and The substituents may include cyclic, acyclic, straight chain and / or branched groups, and at least one hydrogen may be replaced with a functional group.
M is a transition metal element of group 6 to 10 and is a low valence (0 to 3 valence) transition metal element, and L is a monodentate or multidentate charged or uncharged plural coordinated to the central metal. It is a ligand. ]   The method for producing an imidazole carbene metal complex according to claim 1, wherein n 'in the general formula (1) is an integer of 1.