English

• Since the discovery of the first rare‐earth metal imides in the early 1990s, the chemistry of those species has attracted intense attention due to their unique structure, bonding mode, and reactivity^[1]. For the mismatch of the orbital energy between rare‐earth metal ions and the imido groups, the RN^2- moieties of rare‐earth metal imides tended to adopt bridging modes (μ₂ ‐, μ₃ ‐, and μ₄ ‐), thus forming more stable bi‐and multi‐nuclear structures^[2-3]. The existence of a transient terminal imidoscandium species was verified by Mindiola and co‐workers in 2008^[4]. Subsequently, Chen and coworkers isolated and characterized the first scandium terminal imido complex through the methan elimination of scandium methyl‑amido mixed complex supported by monoanionic tridentate β‐diketiminato ligand^[5]. Thus far, rare‐earth metal imido complexes are generally synthesized via the following protocols: 􀃬 thermally induced alkane elimination of rare‐earth metal alkyl primary amido precursors^[6], 􀃭 deprotonation of rare‐earth metal primary amido complexes by strong bases^[7], (Ⅲ) redox reaction of divalent rare‐earth metal complexes with azido complexes^[8], 􀃯 double addition of Ln—C/H units across the nitrile^[9-10], and 􀃰 imido transfer reaction from main group metal to rare‐earth metal center^[11].

  It is particularly noteworthy that protocol Ⅰ has proved to be the most efficient approach for synthesizing the terminal rare‐earth metal imides. Meanwhile, another four strategies are viable for generating bridging species.

  The ancillary ligand and R substituent of primary amine RNH₂ are crucial for the synthesis of rare‐earth metal imides. To date, multidentate monoanionicβ‐diketiminato, phosphazene, and trispyrazolylborate ligands have successfully stabilized terminal rare‐earth imides^[12-14]. For RN^2- moiety, the substituted anilines were successfully used to synthesize terminal rare‑ earth imides, while aliphatic amines and silylamines tend to form bridging and Lewis acid complexation^[15].

  Carboranes are a class of polyhedral carbon‐boron molecular clusters featuring 3D aromaticity, which are often considered as 3D analogues of benzene. Their unique structural and electronic properties make them invaluable building blocks for applications ranging from functional materials to versatile ligands^[16-17]. In contrast to substituted aniline, the alternation of the substituted group and the steric bulk of the carborane moiety might provide appropriate steric and electronic demands for terminal rare‐earth metal imides.

  We have recently synthesized a series of rare‐earth metal dialkyl complexes supported by a neutral pyrrolyl‑functionalized amidinate ligand [2‐(2, 5‐Me₂C₄ H₂N)C₆H₄NC(Ph)=NDipp]^- (L, Dipp=2, 6‐ⁱPr₂C₆H₃), and the corresponding rare‐earth metal carboryne complexes were facilely obtained by the reaction of these dialkyl precursors with o‐carborane according to the alkane elimination protocol^[18-19]. As part of our ongoing research on the reactivity of these dialkyl complexes, we now report the reactivity of the yttrium dialkyl complex [Y(L)(CH₂SiMe₃)₂] with 2‐R‐1‐NH₂‐o‐C₂B₁₀H₁₀ (R=CH₃, Ph), and the first yttrium imido complex bearing o‐carborane moiety was obtained and their structure were characterized by single‐crystal X‐ray diffraction.

  1.   Experimental

  1.1   Materials and instruments

  All reactions were carried out in flame‑dried glassware under an atmosphere of dry argon with the exclusion of air and moisture using standard Schlenk techniques or in a drybox. All organic solvents were dried and distilled by standard methods before use. 1‐Ph‐o‐C₂B₁₀H₁₀ was prepared according to literature method^[20]. All chemicals were purchased from either Aldrich, Acros, J & K, or TCI Chemical Co. and used as received unless other noted. Infrared spectra were obtained from KBr pellets prepared in a drybox on a Perkin‐Elmer 1600 Fourier transform spectrometer. ¹H, ¹³C, and ¹¹B spectra were recorded on a Bruker DPX 400 spectrometer at 400, 100, and 128 MHz, respectively. All chemical shifts were reported with references to the residual solvent resonances of the deuterated solvents for proton and carbon chemical shifts, to external BF₃·OEt₂ (δ=0.00) for boron chemical shifts. Melting points were measured on a STUART Melting Point Apparatus SMP40 and were uncorrected. Elemental analyses were performed by the Shanghai Institute of Organic Chemistry, CAS, China.

  1.2   Synthesis of 2‐CH₃‐1‐NH₂‐o‐C₂B₁₀H₁₀ (1a)

  Under an argon atmosphere, a portion of ⁿBuLi (1.6 mol·L^-1 in n‐hexane, 1.1 mL) was added dropwise to a solution of 1‐CH₃‐o‐C₂B₁₀H₁₀ (253 mg, 1.6 mmol) in toluene (Tol, 10 mL) at 0 ℃. The resulting white precipitate was stirred at room temperature for 3 h, after which a solution of benzyl azide (BnN₃, 300 μL, 2.4 mmol) in toluene (5 mL) was added. Upon addition, the white suspension disappeared, and the mixture became an orange solution, which was stirred at room temperature for 12 h. To the resulting solution, 10 mL of glacial acetic acid was added and heated at 90 ℃ for 2 h. After cooling to room temperature, the solvents and acetic acid were removed under reduced pressure. An orange oily residue was obtained, to which diethyl ether was added, and some white solid appeared, which was filtered and washed with diethyl ether. The combined filtrate was concentrated and chromatographed with hexane/ethyl acetate (6∶1, V/V) to give 1a as a white solid (200 mg, 72.2%). ¹H NMR (400 MHz, CDCl₃): δ 2.04 (s, 3H, CH₃), 2.99 (s, 2H, NH₂). ¹³C NMR (100 MHz, CDCl₃): δ 21.3 (CH₃), 79.3, 91.5. ¹¹B{¹H} NMR (128 MHz, CDCl₃): δ -5.9 (1B), -10.2 (3B), -11.0 (4B), -12.9 (2B). Anal. Calcd. for C₃H₁₅B₁₀N(%): C, 20.80; H, 8.73; N, 8.08. Found(%): C, 21.12; H, 9.03; N, 7.88.

  1.3   Synthesis of 2‐Ph‐1‐NH₂‐o‐C₂B₁₀H₁₀ (1b)

  Under an argon atmosphere, a portion of ⁿBuLi (1.6 mol·L^-1 in n‐hexane, 0.55 mL, 0.88 mmol) was added dropwise to a solution of 1‐Ph‐o‐C₂B₁₀H₁₀ (176 mg, 0.8 mmol) in toluene (5 mL) at 0 ℃. The resulting white precipitate was stirred at room temperature for 3 h, after which the solution of benzyl azide (150 μL, 1.2 mmol) in toluene (3 mL) was added. Upon addition, the white suspension disappeared, and the mixture became an orange solution, which was stirred at room temperature for 12 h. To the resulting solution, 5 mL of glacial acetic acid was added and heated at 90 ℃ for 2 h. After cooling to room temperature, the solvents and acetic acid were removed under reduced pressure. An orange oily residue was obtained, to which diethyl ether was added, and some white solid appeared, which was filtered and washed with diethyl ether. The combined filtrate was concentrated and chromatographed with hexane/ethyl acetate (6∶1, V/V) to give 1b as a white solid (100 mg, 53.2%). ¹H NMR (400 MHz, CDCl₃): δ 2.89 (s, 2H, NH₂), 7.39‐7.49 (m, 3H), 7.67‐7.70 (m, 2H). ¹³C NMR (100 MHz, CDCl₃): δ 128.9, 130.7, 131.0, 131.7. ¹¹B{¹H} NMR (128 MHz, CDCl₃): δ -3.4 (1B), -9.1 (1B), -10.0 (2B), -10.8 (2B), -11.5 (2B), -13.5 (2B). Anal. Calcd. for C₈H₁₇B₁₀N(%): C, 40.83; H, 7.28; N, 5.95. Found(%): C, 40.90; H, 7.46; N, 5.66.

  1.4   Synthesis of [Y(L)(2‐CH₃‐1‐NH‐o‐C₂B₁₀H₁₀)₂] (3a)

  To a solution of [Y(L)(CH₂SiMe₃)₂] (142.4 mg, 0.2 mmol) dissolved in 3 mL toluene, a toluene solution containing 1a (69.2 mg, 0.4 mmol) was added at room temperature. The reaction mixture was stirred for about 2 h, after which the volatile components of the mixture were removed under vacuum. The residue was washed with hexane (2×2 mL), and a white solid was obtained (138 mg, 78.4%). Colorless needle crystals suitable for X‐ray diffraction were obtained after storing the toluene solution at -30 ℃ for several days. ¹H NMR (400 MHz, C₆D₆): δ 0.97 (d, J=8.0 Hz, 6H, CHMe₂), 1.23 (d, J=8.0 Hz, 6H, CHMe₂), 1.65 (s, 6H, CH₃), 1.85 (s, 6H, CH₃), 3.15 (m, J=8.0 Hz, 2H, CHMe₂), 3.38 (s, 2H, NH), 6.04 (d, J=8.0 Hz, ¹H), 6.17 (s, 2H), 6.51‐6.59 (m, 3H), 6.69‐6.74 (m, 3H), 6.85‐6.93 (m, 5H). ¹³C NMR (C₆D₆, 100 MHz): δ 13.6, 21.1, 23.8, 25.9, 28.4, 82.4, 107.8, 109.2, 121.6, 123.2, 124.2, 126.0, 126.6, 130.2, 130.3, 137.7, 140.5, 142.0, 144.2, 174.4. ¹¹B{¹H} NMR (C₆D₆, 128 MHz): δ -5.5 (1B), -10.3 (3B), -11.0 (2B), -12.7 (1B), -14.0 (3B). Anal. Calcd. for C₃₇H₆₃B₂₀N₅Y·C₆H₁₄(%): C, 53.29; H, 8.01; N, 7.23. Found(%): C, 53.52; H, 7.83; N, 6.82. IR (KBr pellets, cm^-1): 2 572 (B—H), 3 307 (N—H). m.p. 223 ℃.

  1.5   X‐ray structure determination

  Single crystals were immersed in Paraton‐N oil and sealed under argon in thin‐walled glass capillaries. All data were collected at 173(2) or 250(2) K on a Bruker Kappa Apex Ⅱ Duo Diffractometer using Mo Kα radiation (λ=0.071 073 nm). An empirical absorption correction was applied using the SADABS program. All structures were solved by direct methods and subsequent Fourier difference techniques and refined anisotropically for all non‐hydrogen atoms by full‐matrix least squares calculations on F² using the SHELXTL program package. All hydrogen atoms were geometrically fixed using the riding model. The crystallographic data and refinement specifics of the structural analyses were comprehensively summarized in Table 1 and 2.

  Table 1

  

  Table 1.  Crystallographic data for complexes 3a and 4a

  下载: 导出CSV

  Parameter	3a	4a
  Formula	C43H76B20N5Y	C82H110B20N8Y2
  Formula weight	968.19	1 601.79
  Space group	P21/n	P1
  Crystal system	Monoclinic	Triclinic
  a / nm	1.470 0(5)	1.091 56(6)
  b / nm	1.278 5(4)	1.171 33(7)
  c / nm	3.096 0(10)	1.778 64(11)
  α / (°)		71.166(2)
  β / (°)	102.670(12)	82.074(2)
  γ / (°)		86.487(2)
  Z	4	1
  V / nm3	5.677(3)	2.131 5(2)
  Dc / (Mg·m-3)	1.133	1.248
  μ / mm-1	1.062	1.403
  F(000)	2 032.0	836.0
  Reflection collected	75 345	80 001
  Unique reflection	13 690	10 200
  Number of parameters	955	663
  Goodness of fit	1.017	1.040
  θ range / (°)	1.73‐28.186	2.439‐27.949
  R1 [I > 2σ(I)]	0.051 7	0.033 1
  wR2 [I > 2σ(I)]	0.130 0	0.083 9
  Rint	0.068 3	0.040 5
  Largest diff. peak and hole / (e·nm-3)	520 and -420	810 and -550

  Table 2

  

  Table 2.  Selected bond lengths (nm) and angles (°) for complexes 3a and 4a

  下载: 导出CSV

  3a
  Y1—N1	0.220 3(2)	Y1—N2	0.222 4(2)	Y1—C37	0.290 6(3)
  Y1—C38	0.275 7(3)	Y1—C39	0.285 5(3)	Y1—C40	0.307 2(2)
  Y1—N3	0.238 8(2)	Y1—N4	0.233 1(2)	Y1—N5	0.306 7(2)
  Y1…Pyrcent*	0.268 8(2)
  N1—Y1—N2	101.79(10)	N3—Y1—N4	55.71(7)	Pyrcent…Y1—N4	78.90(10)
  Pyrcent…Y1—N3	124.75(10)	Pyrcent…Y1—N1	122.20(10)	Pyrcent…Y1—N2	113.49(10)
  4a
  Y1—C4	0.279 88(19)	Y1—C5	0.286 0(2)	Y1—N2	0.242 67(13)
  Y1—N3	0.243 4(13)	Y1—N4	0.224 1(14)	Y1—N4i	0.226 4(14)
  Y1…Pyrcent	0.289 3(3)
  N2—Y1—N3	55.02(4)	N4—Y1—N4i	76.51(5)	Y1—N4—Y1i	103.49(5)
  Pyrcent…Y1—N2	68.626(33)	Pyrcent…Y1—N3	109.211(34)	Pyrcent…Y1—N4	105.859(38)
  Pyrcent…Y1—N4i	127.830(37)
  *Pyrcent=the pyrrolyl ring centroid; Symmetry code: i 1-x, 1-y, 1-z for 4a.

  2.   Results and discussion

  2.1   Synthesis of compounds 1a and 1b

  The compounds 1a and 1b were prepared by lithiation of the corresponding 1‐substituted‐o‐carborane and then reacted with 1.5 equivalents of benzyl azide, followed by treatment of the mixture with acetic acid (Scheme 1). These complexes were characterized by NMR spectroscopy. In their ¹H NMR spectra, the singlets at δ of 2.99 and 2.89 are assigned to the amino groups of 1a and 1b, respectively, which are comparable to that in 1‐amino‐o‐carborane (δ=3.00)^[21]. Their ¹¹B NMR spectra displayed distinct patterns: 1∶3∶4∶2 for 1a and 1∶1∶2∶2∶2∶2 for 1b in a δ range of -2 to -14.

  Scheme 1

  

  Scheme 1.  Synthesis of 2‐R‐1‐NH₂‐o‐C₂B₁₀H₁₀

  下载: 全尺寸图片 幻灯片

  2.2   Reactivity of [Y(L)(CH₂SiMe₃)₂] with 2‐R‐1‐NH₂‐o‐C₂B₁₀H₁₀ (R=CH₃, Ph)

  In light of the rare‐earth metal imido complex that can be generated by thermally induced alkane elimination of alkyl‐anilido complex, the reaction of [Y(L)(CH₂SiMe₃)₂] with an equivalent of 1a was monitored using ¹H NMR spectroscopy. The anticipated protonation indeed occurred with the release of tetramethyl silane, however, a mixture of yttrium alkyl‐amido complex 2a and the bis(amido) complex 3a was obtained in C₆D₆ or THF‐d₈ at ambient temperature (Scheme 2). The reaction of [Y(L)(CH₂SiMe₃)₂] with an equivalent of 1b, which bears more bulky phenyl groups, also gave a mixture of 2b and 3b. To verify whether the yttrium bis(amido) complex 3 was formed by the disproportionation of the yttrium alkyl‐amido complex 2, the reaction mixture was heated at 55 ℃ for 12 h, resulting in the formation of the yttrium imido complex 4a. Complex 4a was formed through the alkane elimination from complex 2a (Scheme 3). These results suggest that the formation of yttrium bis(amido) complex 3 might for the greater Brønsted acidity of precursor 1 compared to substituted aniline. Attempts to isolate the pure amido‐alkyl complex were unsuccessful even when the reaction was performed at -30 ℃.

  Scheme 2

  

  Scheme 2.  Reaction of yttrium dialkyl complex with one equivalent of compound 1

  下载: 全尺寸图片 幻灯片

  Scheme 3

  

  Scheme 3.  Synthesis of complex 4a

  下载: 全尺寸图片 幻灯片

  The yttrium bis(amido) complex 3a was independently prepared by treatment of [Y(L)(CH₂SiMe₃)₂] with two equivalents of 1a in toluene (Scheme 4). Complex 3a was fully characterized by spectroscopic techniques. The NH moiety was observed at δ of 3.38 in the ¹NMR spectrum, and a stretching vibration was detected at 3 307 cm^-1 in the IR spectrum. The ¹¹B NMR spectrum exhibited a 1∶3∶2∶1∶3 pattern, different from complex 1a.

  Scheme 4

  

  Scheme 4.  Reaction of yttrium dialkyl complex with two equivalents of compound 1a

  下载: 全尺寸图片 幻灯片

  2.3   Crystal structure analysis of complexes 3a and 4a

  Crystal structures of complexes 3a and 4a with atom numbering are shown in Fig. 1 and 2, respectively. Single‐crystal X‐ray diffraction revealed that 3a crystallizes in the monomeric structure with monoclinic P2₁/n space group and 4a in the dimeric structure with triclinic P1 space group. In these complexes, the ligand coordinates to the yttrium center through both the neutral pyrrolyl ring and amidinate moieties, similar to their parent complex [Y(L)(CH₂SiMe₃)₂]. The coordination sphere of the yttrium center is further completed by two nitrogen atoms from the amido group for 3a and the imido group for 4a. The geometry of these complexes is best described as a four‐legged piano stool. The distance between the yttrium ion and the pyrrolyl ring centroid of 0.268 8(2) nm in 3a is comparable to that detected in [Y(L)(CH₂SiMe₃)₂] [0.268 9(8) nm] and slightly shorter than in 4a [0.289 3(3) nm]. The Y—N amidinato bond lengths of 0.238 8(2) and 0.233 1(2) nm in 3a are also shorted than in 4a [0.2426 7(13)‐0.243 4(13) nm]. The Y—N amido bond lengths of 0.220 3(2) and 0.222 4(2) nm in 3a are comparable to those in the five‐coordinated yttrium bis(amido) complex [Ph₂PNC₆H₃(ⁱPr₂)₂]₂NY[NHC₆H₃(ⁱPr)₂]₂ [0.221 1(3)‐0.220 6(3) nm] but shorter than in Cp*Y(NHC₆H₃ (CF₃)₂)₂(thf)₂ and Cp*Y(NHC₆H₃ⁱPr₂)₂(thf)₂ (Cp*=C₅Me₅) [0.229 3(3)‐0.229 4(3) nm/0.227 1(1)‐0.225 8(1) nm]^[22]. The Y—N imido bond lengths of 0.224 1(14) and 0.226 4(14) nm in 4a are comparable to the distances in the seven‑coordinated yttrium imide complex [Cp*Y(NC₆H₃(CF₃)₂(thf)₂]₂ (Cp*=C₅Me₅) [0.222 2(4)‐0.230 4(4) nm]^[22].

  Figure 1

  

  Figure 1.  Molecular structure of complex 3a

  All atoms are represented by ellipsoid probability at 30%; Solvent molecule, hydrogen atoms except for those of N—H, and the disorder in 2‐methyl‐ o‐carboryl groups are omitted for clarity.

  下载: 全尺寸图片 幻灯片

  Figure 2

  

  Figure 2.  Molecular structure of complex 4a

  All atoms are represented by ellipsoid probability at 30%; Solvent molecule, hydrogen atoms, and the disorder in phenyl, isopropyl, and 2‐methyl‐o‐carboryl groups are omitted for clarity; Symmetry code: ⁱ 1-x, 1-y, 1-z.

  下载: 全尺寸图片 幻灯片

  3.   Conclusions

  2‐Substituted‐1‐amino‐o‐carboranes were synthesized, and their reactivity with the yttrium dialkyl complex [Y(L)(CH₂SiMe₃)₂] (L=[2‐(2, 5‐Me₂C₄H₂N)C₆H₄NC(Ph)=NDipp]^-, Dipp=2, 6‐ⁱPr₂C₆H₃) was investigated. The formation of the reaction is highly dependent on the stoichiometry of the reactants. When one equivalent of the amine was employed, a mixture of the yttrium bis(amido) complex [Y(L)(2‐R‐1‐NH‐o‐C₂B₁₀H₁₀)₂] and the alkyl‐amido complex [Y(L)(2‐R‐1‐NH‐o‐C₂B₁₀H₁₀)(CH₂SiMe₃)] (R=CH₃, Ph) was obtained. The reaction of [Y(L)(CH₂SiMe₃)₂] with two equivalents of 2‐CH₃‐1‐NH₂‐o‐C₂B₁₀H₁₀ resulted only in the isolation of the bis(amido) complex. Furthermore, the bridging imido complex [Y(L)(2‐CH₃‐1‐N‐o‐C₂B₁₀H₁₀)]₂ was formed, and its structure was characterized through the alkane elimination of the corresponding alkyl‐amido complex.

  
  Supporting information is available at http://www.wjhxxb.cn
  
• 1. [1]

     TRIFONOV A A, BOCHKAREV M N, SCHUMANN H, LOEBEL J. Reduction of azobenzene by naphthaleneytterbium: A tetranuclear ytterbium(Ⅲ) complex combining 1, 2‐diphenylhydrazido(2-) and phenylimido ligands[J]. Angew. Chem.‒Int. Edit., 1991, 30(9):  1149-1151. doi: 10.1002/anie.199111491

  2. [2]

     LIU Z X, CHEN Y F. One frontier of the rare‐earth organometallic chemistry: The chemistry of rare‐earth metal alkylidene, imido and phosphinidene complexes[J]. Sci. China Chem., 2011, 41(2):  304-313.

  3. [3]

     SCHÄDLE D, ANWANDER R. Rare‐earth metal and actinide organoimide chemistry[J]. Chem. Soc. Rev., 2019, 48(24):  5752-5805. doi: 10.1039/C8CS00932E

  4. [4]

     SCOTT J, BASULI F, FOUT A R, HUFFMAN J C, MINDIOLA D J. Evidence for the existence of a terminal imidoscandium compound: Intermolecular C—H activation and complexation reactions with the transient Sc=NAr species[J]. Angew. Chem.‒Int. Edit., 2008, 47(44):  8502-8505. doi: 10.1002/anie.200803325

  5. [5]

     LU E L, LI Y X, CHEN Y F. A scandium terminal imido complex: Synthesis, structure and DFT studies[J]. Chem. Commun., 2010, 46(25):  4469-4471. doi: 10.1039/c002870c

  6. [6]

     LU E L, CHU J X, CHEN Y F. Scandium terminal imido chemistry[J]. Acc. Chem. Res., 2018, 51(2):  557-566. doi: 10.1021/acs.accounts.7b00605

  7. [7]

     CHAN H S, LI H W, XIE Z W. Synthesis and structural characterization of imido‐lanthanide complexes with a metal‐nitrogen multiple bond[J]. Chem. Commun., 2002, (6):  652-653. doi: 10.1039/b110793c

  8. [8]

     PAN C L, CHEN W, SONG S Y, ZHANG H J, LI X W. Stabilization of imidosamarium(Ⅲ) cubane by amidinates[J]. Inorg. Chem., 2009, 48(14):  6344-6346. doi: 10.1021/ic900808f

  9. [9]

     BEETSTRA D J, MEETSMA A, HESSEN B, TEUBEN J H. (Cyclo-pentadienylamine)scandium(2, 3‐dimethyl‐1, 3‐butadiene): A 1, 3‐diene complex of scandium with Sc􀃬‐and Sc(Ⅲ)‐like reactivity[J]. Organometallics, 2003, 22(22):  4372-4374. doi: 10.1021/om030267h

  10. [10]

      CUI D M, TARDIF O, HOU Z M. Tetranuclear rare earth metal polyhydrido complexes composed of "(C₅Me₄SiMe₃)LnH₂" units. Unique reactivities toward unsaturated C—C, C—N, and C—O bonds[J]. J. Am. Chem. Soc., 2004, 126(5):  1312-1313. doi: 10.1021/ja039324o

  11. [11]

      BERTHET J C, THUÉRY P, EPHRITIKHINE M. Polyimido clusters of neodymium and uranium, including a cluster with an M₆(μ₃‐N)₈ Core[J]. Eur. J. Inorg. Chem., 2008, (35):  5455-5459.

  12. [12]

      LU E L, CHU J X, CHEN Y F. Scandium terminal imido complex induced C—H bond selenation and formation of an Sc—Se bond[J]. Chem. Commun., 2011, 47(2):  743-745. doi: 10.1039/C0CC03212C

  13. [13]

      RONG W F, CHENG J H, MOU Z H, XIE H Y, CUI D M. Facile preparation of a scandium terminal imido complex supported by a phosphazene ligand[J]. Organometallics, 2013, 32(19):  5523-5529. doi: 10.1021/om400803q

  14. [14]

      SCHÄDLE D, MEERMANN ‐ ZIMMERMANN M, SCHÄDLE C, MAICHLE‐ MÖSSMER C, ANWANDER R. Rare‐earth metal complexes with terminal imido ligands[J]. Eur. J. Inorg. Chem., 2015, (8):  1334-1339.

  15. [15]

      HONG J Q, ZHANG L X, WANG K, ZHANG Y, WENG L H, ZHOU X G. Methylidene rare‐earth‐metal complex mediated transformations of C=N, N=N and N—H bonds: New routes to imido rare‐earth‐metal clusters[J]. Chem.‒Eur. J., 2013, 19(24):  7865-7873. doi: 10.1002/chem.201300440

  16. [16]

      李欢欢, 燕红, 芦昌盛. 碳硼烷硼氢键选择性官能团化的研究进展[J]. 无机化学学报, 2017,33,(8): 1313-1329. LI H H, YAN H, LU C S. Progress in selective B—H bond functionalization of carborane[J]. Chinese J. Inorg. Chem., 2017, 33(8):  1313-1329.

  17. [17]

      ZHANG X L, YAN H. Transition metal‐induced B—H functionalization of o‐carborane[J]. Coord. Chem. Rev., 2019, 378:  466-482. doi: 10.1016/j.ccr.2017.11.006

  18. [18]

      GUO L P, GUO C J, PENG S Q, SONG R Y. Synthesis, structure, and coordination chemistry of a neutral pyrrolyl‐functionalized amidinate ligand[J]. New J. Chem., 2022, 46(5):  2465-2471. doi: 10.1039/D1NJ05548H

  19. [19]

      GUO L P, WANG S W, XIE Z W. Synthesis, structure, and reactivity of rare‐earth metal carboryne complexes[J]. Organometallics, 2023, 42(7):  581-587. doi: 10.1021/acs.organomet.3c00002

  20. [20]

      TANG C, XIE Z W. Nickel‐catalyzed cross‐coupling reactions of o‐carboranyl with aryl iodides: Facile synthesis of 1‐aryl‐o‐carboranes and 1, 2‐diaryl‐o‐carboranes[J]. Angew. Chem.‒Int. Edit., 2015, 54(26):  7662-7665. doi: 10.1002/anie.201502502

  21. [21]

      NIE Y, WANG Y F, MIAO J L, LI Y X, ZHANG Z W. Synthesis and characterization of carboranyl Schiff base compounds from 1‐amino‐o‐carborane[J]. J. Organomet. Chem., 2015, 798:  182-188. doi: 10.1016/j.jorganchem.2015.05.046

  22. [22]

      THIM R, DIETRICH H M, BONATH M, MAICHLE‐MÖSSMER C, ANWANDER R. Pentamethylcyclopentadienyl‐supported rare‐earth‐metal benzyl, amide, and imide complexes[J]. Organometallics, 2018, 37(16):  2769-2777. doi: 10.1021/acs.organomet.8b00420

• 

  Scheme 1  Synthesis of 2‐R‐1‐NH₂‐o‐C₂B₁₀H₁₀

  下载: 全尺寸图片 幻灯片
  

  Scheme 2  Reaction of yttrium dialkyl complex with one equivalent of compound 1

  下载: 全尺寸图片 幻灯片
  

  Scheme 3  Synthesis of complex 4a

  下载: 全尺寸图片 幻灯片
  

  Scheme 4  Reaction of yttrium dialkyl complex with two equivalents of compound 1a

  下载: 全尺寸图片 幻灯片
  

  Figure 1  Molecular structure of complex 3a

  All atoms are represented by ellipsoid probability at 30%; Solvent molecule, hydrogen atoms except for those of N—H, and the disorder in 2‐methyl‐ o‐carboryl groups are omitted for clarity.

  下载: 全尺寸图片 幻灯片
  

  Figure 2  Molecular structure of complex 4a

  All atoms are represented by ellipsoid probability at 30%; Solvent molecule, hydrogen atoms, and the disorder in phenyl, isopropyl, and 2‐methyl‐o‐carboryl groups are omitted for clarity; Symmetry code: ⁱ 1-x, 1-y, 1-z.

  下载: 全尺寸图片 幻灯片

  Table 1.  Crystallographic data for complexes 3a and 4a

  Parameter	3a	4a
  Formula	C43H76B20N5Y	C82H110B20N8Y2
  Formula weight	968.19	1 601.79
  Space group	P21/n	P1
  Crystal system	Monoclinic	Triclinic
  a / nm	1.470 0(5)	1.091 56(6)
  b / nm	1.278 5(4)	1.171 33(7)
  c / nm	3.096 0(10)	1.778 64(11)
  α / (°)		71.166(2)
  β / (°)	102.670(12)	82.074(2)
  γ / (°)		86.487(2)
  Z	4	1
  V / nm3	5.677(3)	2.131 5(2)
  Dc / (Mg·m-3)	1.133	1.248
  μ / mm-1	1.062	1.403
  F(000)	2 032.0	836.0
  Reflection collected	75 345	80 001
  Unique reflection	13 690	10 200
  Number of parameters	955	663
  Goodness of fit	1.017	1.040
  θ range / (°)	1.73‐28.186	2.439‐27.949
  R1 [I > 2σ(I)]	0.051 7	0.033 1
  wR2 [I > 2σ(I)]	0.130 0	0.083 9
  Rint	0.068 3	0.040 5
  Largest diff. peak and hole / (e·nm-3)	520 and -420	810 and -550

  下载: 导出CSV

  Table 2.  Selected bond lengths (nm) and angles (°) for complexes 3a and 4a

  3a
  Y1—N1	0.220 3(2)	Y1—N2	0.222 4(2)	Y1—C37	0.290 6(3)
  Y1—C38	0.275 7(3)	Y1—C39	0.285 5(3)	Y1—C40	0.307 2(2)
  Y1—N3	0.238 8(2)	Y1—N4	0.233 1(2)	Y1—N5	0.306 7(2)
  Y1…Pyrcent*	0.268 8(2)
  N1—Y1—N2	101.79(10)	N3—Y1—N4	55.71(7)	Pyrcent…Y1—N4	78.90(10)
  Pyrcent…Y1—N3	124.75(10)	Pyrcent…Y1—N1	122.20(10)	Pyrcent…Y1—N2	113.49(10)
  4a
  Y1—C4	0.279 88(19)	Y1—C5	0.286 0(2)	Y1—N2	0.242 67(13)
  Y1—N3	0.243 4(13)	Y1—N4	0.224 1(14)	Y1—N4i	0.226 4(14)
  Y1…Pyrcent	0.289 3(3)
  N2—Y1—N3	55.02(4)	N4—Y1—N4i	76.51(5)	Y1—N4—Y1i	103.49(5)
  Pyrcent…Y1—N2	68.626(33)	Pyrcent…Y1—N3	109.211(34)	Pyrcent…Y1—N4	105.859(38)
  Pyrcent…Y1—N4i	127.830(37)
  *Pyrcent=the pyrrolyl ring centroid; Symmetry code: i 1-x, 1-y, 1-z for 4a.

  下载: 导出CSV
•