Preparation of organocobalt complexes through CF/CH bond activation of polyfluoroaryl imines

Article abstract of DOI:10.1016/j.inoche.2014.02.017

In this paper, we reported the CF and CH bond activation of polyfluoroimine ligands induced by CoMe(PMe₃)₄. The reaction of pentafluorophenylmethylidene-2,6-diisopropylaniline 1 with CoMe(PMe ₃)₄ afforded an ortho-chelated cobalt(I) complex [Co(PMe₃)₃(C₆F₄-ortho-CH = N-C ₆H₃(iso-Pr)_{2(ortho, ortho)})] (5) via CF bond activation and subsequent elimination of methyl fluoride. Under similar reaction conditions, the reactions of polyfluoroaryl imines 2-4 with CoMe(PMe ₃)₄ afforded the penta-coordinate cobalt(I) complexes 6-8 via CH bond activation and subsequent elimination of methane [Co(PMe ₃)₃(C₆H₂F _{2(meta, meta)}-ortho-(CH = N-C₆H₄Cl _para)] (6), [Co(PMe₃)₃(C₆H ₂F_{2(meta, para)}-ortho-(CH = N-C₆H ₄Cl_para)] (7), and [Co(PMe₃)₃(C ₆HF_{3(meta, meta, para)}-ortho-(CH = N-C₆H ₄Cl_para)] (8). Complexes 5-8 were characterized through IR, ¹H NMR, ³¹P NMR, ¹⁹F NMR and elemental analyses. The crystal and molecular structures of complexes 5, 6 and 8 were determined by X-ray single crystal diffraction. The reactions of 8 with MeI and EtBr afforded organic fluorides 9-10. A proposed formation mechanism of 9-10 with the oxidative addition of RX at the cobalt(I) center of 8 and reductive elimination via C,C-coupling was discussed.

Full text of DOI:10.1016/j.inoche.2014.02.017

Inorganic Chemistry Communications 43 (2014) 110–113
Contents lists available at ScienceDirect
Inorganic Chemistry Communications
journal homepage: www.elsevier.com/locate/inoche
Preparation of organocobalt complexes through C\F/C\H bond
activation of polyfluoroaryl imines
⁎
Faguan Lu, Hongjian Sun, Lin Wang, Xiaoyan Li
School of Chemistry and Chemical Engineering, Key Laboratory of Special Functional Aggregated Materials, Ministry of Education, Shandong University, Shanda Nanlu 27, 250199 Jinan, PR China
a r t i c l e i n f o
a b s t r a c t
Article history:
In this paper, we reported the C\F and C\H bond activation of polyfluoroimine ligands induced by CoMe(PMe3)4.
The reaction of pentafluorophenylmethylidene-2,6-diisopropylaniline 1 with CoMe(PMe3)4 afforded an ortho-
chelated cobalt(I) complex [Co(PMe3)3(C6F4-ortho-CH = N-C6H3(iso-Pr)2(ortho, ortho))] (5) via C\F bond activation
and subsequent elimination of methyl fluoride. Under similar reaction conditions, the reactions of polyfluoroaryl
imines 2–4 with CoMe(PMe3)4 afforded the penta-coordinate cobalt(I) complexes 6–8 via C\H bond activation
and subsequent elimination of methane [Co(PMe3)3(C6H2F2(meta, meta)-ortho-(CH = N-C6H4Clpara)] (6),
[Co(PMe3)3(C6H2F2(meta, para)-ortho-(CH = N-C6H4Clpara)] (7), and [Co(PMe3)3(C6HF3(meta, meta, para)-ortho-(CH =
N-C6H4Clpara)] (8). Complexes 5–8 were characterized through IR, 1H NMR, 31P NMR, 19F NMR and elemental
analyses. The crystal and molecular structures of complexes 5, 6 and 8 were determined by X-ray single
crystal diffraction. The reactions of 8 with MeI and EtBr afforded organic fluorides 9–10. A proposed
formation mechanism of 9–10 with the oxidative addition of RX at the cobalt(I) center of 8 and reductive
elimination via C,C-coupling was discussed.
Received 13 January 2014
Accepted 15 February 2014
Available online 22 February 2014
Keywords:
C\H activation
C\F activation
Cobalt complex
C,C-coupling
Trimethylphosphine
© 2014 Elsevier B.V. All rights reserved.
Fluorinated aromatic compounds are important components in
diverse fields of science and technology, including pharmaceuticals
and agrochemicals [1]. However, there are no identified natural
fluoroaromatic building blocks, which must be generated by synthesis
[2]. A feasible and direct approach is to functionalize aryl fluoride via
C\H or C\F bond activation by transition–metal complexes. There
have been some reports on C\F and C\H bond activation of fluorinated
compounds with Ru, Rh, Pd, Ni, and Fe complexes [3–13]. By contrast,
few publications were disclosed on cobalt mediated C\F and C\H
bond activation of polyfluoroorganic compounds. Holland provided
the research result of C\F bond activation of fluorobenzene by
low-coordinated cobalt complex [14]. Klein published the selective
ortho-(C\H) and (C\F) bond activation of arylketones at cobalt centers
[15].
In recent years, we focused our research in the field of C\F or C\H
bond activation and functionalization of polyfluoroorganic compounds
mediated by electron-rich cobalt complexes. After isolation and charac-
terization of the first cobalt(III) complex containing a [C–Co–F]
fragment through C\F bond activation of fluorinated imine with
CoMe(PMe3)4 in 2006 [16], a series of organocobalt complexes were
synthesized through C\F bond activation [17–21]. As a continuation
of our research, in this paper, we present the recent results of our study
on C\F or C\H bond activation of fluorinated imines (1–4) by
CoMe(PMe3)4. Four organocobalt complexes (5–8) were prepared and
characterized. The reactivity of complex 8 with MeI and EtBr was also
investigated.
The reactions of pentafluorophenylmethylidene-2,6-diisopropylaniline
1 [18] with CoMe(PMe3)4 afforded a penta-coordinate cobalt(I) complex
5 via C\F bond activation and subsequent elimination of methyl fluoride
(Scheme 1) [22].
Cobalt(I) complex 5 was isolated as dark brown crystals in the yield of
66% by crystallization from pentane at 4 °C. Complex 5 in the solid state is
stable for several hours at room temperature. In the infrared spectrum of
complex 5, the ν(C_N) band was recorded at 1621 cm−1. Compared
with the C_N band (1648 cm−1) of compound 1, this substantial red
shift upon coordination of the N-donor atom of the imine group indicates
a weakening of the C_N double bond after coordination to the cobalt
center. In the 1H NMR spectrum, an imine-H proton was recorded at
8.88 ppm as a singlet while the 27 protons of the three PMe3 ligands
were found at 0.84 ppm as a doublet (9H, 2JPH = 9 Hz) and at 1.13 ppm
as a singlet (18H) in the integral ratio of 1: 2. In the 31P NMR spectrum,
three broad singlets at −1.26, −15.85 and −16.07 ppm with the integral
ratio of 1:1:1 suggest that the three phosphorus atoms have different
chemical environments.
The spectroscopic information indicates that complex 5 is a penta-
coordinate compound. This was confirmed by X-ray diffraction (Fig. 1)
[23]. Complex 5 has a trigonal bipyramid geometry (TBP) with P2, P3
and N1 atoms in the equatorial plane. The three bond angles in this
⁎
Corresponding author. Tel.: +86 531 88361350; fax: +86 531 88564464.
E-mail address: xli63@sdu.edu.cn (X. Li).
http://dx.doi.org/10.1016/j.inoche.2014.02.017
1387-7003/© 2014 Elsevier B.V. All rights reserved.

F. Lu et al. / Inorganic Chemistry Communications 43 (2014) 110–113
111
F
F
F
F
F
F
F
F
F
F
+ PMe3
- MeF
N
N
N
+
CoMe(PMe3)4
- 2 PMe3
F
Co
Co
F
F
PMe3
PMe3
F
Me
Me3P
Me3P
PMe3
1
5a
5
Scheme 1. Reaction of 1 with CoMe(PMe3)4.
plane are N1–Co1–P2 118.34(7)°, N1–Co1–P3 123.23(7)° and P3–Co1–
P2 116.45(4)° with the sum of 358.2°. P1 and C6 atoms are located in the
axial positions with a bond angle of C6–Co1–P1 177.58(9)°. The
axial bond distance Co1–P1 (2.2348(9) Å) is remarkably longer
than the equatorial bond distance Co1–P2 (2.2200(9) Å) or Co1–P3
(2.2138(10) Å) due to the TBP geometry [24].
cobalt(I) complexes 6–8 via C\H bond activation and subsequent elim-
ination of methane (Eq. (2)) [22].
Complexes 6, 7 and 8 were obtained as dark green crystals by crys-
tallization from pentane at 4 °C in the yields of 53–80%. In the infrared
spectra of complexes 6–8, the characteristic ν(C_N) bands were
recorded at 1590 (6), 1589 (7) and 1605 cm−1 (8). In the 1H NMR spec-
tra, the imine-H proton resonances are located at 9.13 (6), 9.43 (7) and
9.02 ppm (8) as a singlet. PMe3 proton resonance was recorded as a
doublet (9H) and a singlet (18H). In the 31P NMR spectra, three singlets
are registered with the integral ratio of 1:1:1. All of the spectroscopic
information indicates that complexes 6–8 have the structure as shown
in Eq. (2). This conjecture was further confirmed by X-ray single crystal
analysis (Figs. 2–3) [23].
Complexes 6 and 8 have similar structures as complex 5. Both of them
have a trigonal bipyramid geometry with two P atoms and one N atom in
the triangular plane. The third P and C atoms of the fluoroaromatic ring
are located in the axial positions. In this case, C\H bond is easier to be
activated, especially with the escape of methane. Complexes 6–8 are not
stable in the air.
According to our early report on the C\F bond activation of 2,6-
difluorinated imines with CoMe(PMe3)4 (Eq. (1)) [17], oxidative addi-
tion of the ortho-(C\F) bond at the cobalt(I) center is the first step via
cyclometalation with the imine as an anchoring group to form an inter-
mediate cobalt(III) 5a containing a [C–Co–F] fragment (Scheme 1).
However, 5a with four electron-withdrawing fluorine atoms on the
phenyl ring is not stable as the product in Eq. (1) with one fluorine
atom on the phenyl ring. This instability is probably caused by the
weaker coordination ability of the imine-N atom in 5a. In addition, the
larger steric hindrance, the iso-propyl groups close to the C_N, is ben-
eficial to the C,C-coupling reaction. Reductive elimination of 5a afforded
cobalt(I) complex 5 with the escape of MeF.
Under similar reaction conditions, the reactions of polyfluoroaryl
imines 2–4 [18] with CoMe(PMe3)4 afforded the penta-coordinate
Fig. 1. Molecular structure of 5 (all the hydrogen atoms were omitted for clarity). Selected
bond distances (Å) and angles (°): Co1–N1 1.958(2), Co1–C6 1.981(3), Co1–P3 2.214(1),
Co1–P2 2.2200(9), Co1–P1 2.2348(9), N1–C7 1.319(3); N1–Co1–C6 81.0(1), N1–Co1–P3
123.23(7), C6–Co1–P3 88.60(9), N1–Co1–P2 118.34(7), C6–Co1–P2 86.58(8), P3–Co1–
P2 116.45(4), N1–Co1–P1 96.79(7), C6–Co1–P1 177.58(9), P3–Co1–P1 93.36(4), P2–
Co1–P1 93.80(3).
Fig. 2. Molecular structure of complex 6 (all the hydrogen atoms were omitted for clarity).
Selected bond distances (Å) and angles (°): Co1–C15 1.942(2), Co1–N1 1.949(2), Co1–P2
2.1882(7), Co1–P1 2.1911(7), Co1–P3 2.2314(8), N1–C22 1.313(3); C15–Co1–N1
81.89(8), C15–Co1–P2 87.10(6), N1–Co1–P2 128.30(5), C15–Co1–P1 84.73(6), N1–Co1–
P1 112.43(5), P2–Co1–P1 116.59(3), C15–Co1–P3 178.56(6), N1–Co1–P3 96.87(6), P2–
Co1–P3 94.26(3), P1–Co1–P3 95.09(2).

112
F. Lu et al. / Inorganic Chemistry Communications 43 (2014) 110–113
Acknowledgment
We gratefully acknowledge the financial support by NSF China
(No. 21172132) and the support from Prof. Dr. Dieter Fenske and
Dr. Olaf Fuhr (Karlsruhe Nano-Micro Facility) on the determination of
the crystal structures.
Appendix A. Supplementary material
CCDC 927670 (5), 927669 (6) and 974818 (8) contain the supple-
mentary crystallographic data for this paper. These data can be obtained
free of charge via http://www.ccdc.cam.ac.uk/conts/retrieving.html,
or from the Cambridge Crystallographic Data Centre, 12 Union
Road, Cambridge CB2 1EZ, UK; fax: (+44) 1223-336-033; or e-mail:
deposit@ccdc.cam.ac.uk. Supplementary data associated with this
article can be found, in the online version, at http://dx.doi.org/10.
1016/j.inoche.2014.02.017.
Fig. 3. Molecular structure of complex 8 (all the hydrogen atoms were omitted for clarity).
Selected bond distances (Å) and angles (°): Co1–N1 1.959(2), Co1–C6 1.960(3), Co1–P1
2.2146(7), Co1–P1A 2.2146(7), Co1–P2 2.2462(9), N1–C12 1.317(4); N1–Co1–C6
81.4(1), N1–Co1–P1 121.33(2), C6–Co1–P1 87.99(5), N1–Co1–P1A 121.33(2), C6–Co1–
P1A 87.99(5), P1–Co1–P1A 115.67(4), N1–Co1–P2 95.93(8), C6–Co1–P2 177.31(9), P1–
Co1–P2 93.44(3), P1A–Co1–P2 93.44(3).
References
[1] K. Müller, C. Faeh, F. Diederich, Science 317 (2007) 1881–1886.
[2] T. Furuya, J.E.M.N. Klein, T. Ritter, Synthesis 11 (2010) 1804–1821.
[3] J.L. Kiplinger, T.G. Richmond, J. Am. Chem. Soc. 118 (1996) 1805–1806.
[4] J.L. Kiplinger, T.G. Richmond, C.E. Osterberg, Chem. Rev. 94 (1994) 373–431.
[5] M. Crespo, Organometallics 14 (1995) 355–364.
[6] H. Amii, K. Uneyama, Chem. Rev. 109 (2009) 2119–2183.
[7] E.F. Murphy, R. Murugavel, H.W. Roesky, Chem. Rev. 97 (1997) 3425–3468.
[8] M. Aizenberg, D. Milstein, Science 265 (1994) 359–361.
[9] M. Weydert, R.A. Andersen, R.G. Bergman, J. Am. Chem. Soc. 115 (1993) 8837–8838.
[10] B.L. Edelbach, W.D. Jones, J. Am. Chem. Soc. 119 (1997) 7734–7742.
[11] B.M. Kraft, R.J. Lachicotte, W.D. Jones, J. Am. Chem. Soc. 123 (2001) 10973–10979.
[12] R.J. Young Jr., V.V. Grushin, Organometallics 18 (1999) 294–296.
[13] M. Aizenberg, D. Milstein, J. Am. Chem. Soc. 117 (1995) 8674–8675.
[14] T.R. Dugan, J.M. Goldberg, W.W. Brennessel, P.L. Holland, Organometallics 31 (2012)
1349–1360.
Among organic halides, MeI and EtBr are normally used as oxidants
because of their good chemical activity. The pentane solution of com-
plex 8 was reacted with MeI and EtBr (Eq. (3)). After work-up, column
chromatographic separation using petroleum ether/triethylamine
(200:1) as developing agent led to organic fluorides 9–10 in the yield
of ca. 90%. Compounds 9 and 10 were characterized by 1H, 19F, and 13
C
NMR spectra and mass spectrum. As byproducts, CoCl(PMe3)3 and
CoBr(PMe3)3 were confirmed by IR spectrum [25].
[15] S. Camadanli, R. Beck, U. Flörke, H.-F. Klein, Dalton Trans. 42 (2008) 5701–5704.
[16] X. Li, H. Sun, F. Yu, U. Flörke, H.-F. Klein, Organometallics 25 (2006) 4695–4697.
[17] T. Zheng, H. Sun, Y. Chen, X. Li, S. Dürr, U. Radius, K. Harms, Organometallics 28
(2009) 5771–5776.
[18] Z. Lian, X. Xu, H. Sun, Y. Chen, T. Zheng, X. Li, Dalton Trans. 39 (2010) 9523–9529.
[19] T. Zheng, H. Sun, J. Ding, Y. Zhang, X. Li, J. Organomet. Chem. 695 (2010) 1873–1877.
[20] J. Li, T. Zheng, H. Sun, W. Xu, X. Li, Dalton Trans. 42 (2013) 5740–5748.
[21] F. Lu, H. Sun, X. Li, Chin. J. Chem. 31 (2013) 927–932.
[22] Synthesis of complex 5: A solution of 1 (0.53 g, 1.50 mmol) in diethyl ether (30 mL)
was added to a solution of CoMe(PMe3)4 (0.68 g, 1.80 mmol) in diethyl ether (20 mL)
at −78 °C under N2 atmosphere. The reaction mixture was warmed to ambient tem-
perature and stirred for 12 h. During this period, the red reaction mixture turned dark
brown in color. After filtering, crystallization from ether at 4 °C afforded brown single
crystals of 5 (0.61 g, 66 %) suitable for X-ray analysis. Anal. calc. for C28H45CoF4NP3
(623.51 g mol−1): C, 53.94; H, 7.27; N, 2.25%. Found: C, 53.52; H, 7.48; N, 2.46%.
Dec. N127 °C. IR (Nujol mull): 1621 ν(C_N), 943 ν(PMe3) cm−1. NMR data: 1H
NMR (300 MHz, C6D6, 298 K): δ 8.88 (s, 1H, CH = N), 7.35–7.31 (m, 3H, Ar-H),
3.46–3.37 (m, 2H, Ar-CH-Me), 1.36 (d, J = 6.0 Hz, 6H, CH3), 1.18 (d, J = 6.0 Hz, 6H,
CH3), 1.13 (s, 18H, PCH3), 0.84 (d, J = 9.0 Hz, 9H, PCH3), 31P NMR (121 MHz, C6D6,
298 K): δ −1.3 (s, 1P, PMe3), −15.8 (s, 1P, PMe3), −16.1 (s, 1P, PMe3), 19F NMR
(282 MHz, C6D6, 298 K), δ −112.0 (s, 1F), −115.9 (s, 1F), −150.9 (s, 1F), −166.4
(s, 1F). Complexes 6–8 were synthesized according to the similar method as that for
complex 5. Synthesis of 6: Complex 6 as green crystals was obtained in the yield of
71%. Anal. calc. for C22H34ClCoF2NP3 (537.82 g mol−1): C, 49.13; H, 6.37; N, 2.60%.
Found: C, 49.22; H, 6.48; N, 2.54. Dec. N102 °C. IR (Nujol mull): 1590 ν(C_N),
938 ν(PMe3) cm−1. NMR data: 1H NMR (300 MHz, C6D6, 298 K): δ 9.13
(s, 1H, CH = N), 7.82 (d, J = 9Hz, 1H, Ar-H), 7.04 (d, J = 6Hz, 2H, Ar-H), 6.82
(d, J = 9.0 Hz, 2H, Ar-H), 6.59 (t, J = 9.0 Hz, 1H, Ar-H), 0.79 (s, 27H, PCH3),
31P NMR (121 MHz, C6D6, 298 K): δ −0.9 (s, 1P, PMe3), −15.8 (s, 2P, PMe3),
19F NMR (282 MHz, C6D6, 298 K), δ −115.3 (s, 1F), −116.8 (s, 1F). Synthesis
Based upon these experimental results, a proposed mechanism for
reaction (3) is described in Scheme 2. The first step should be the
oxidative addition of RX at the cobalt(I) center of complex 8 to afford
a hexa-coordinate cobalt(III) intermediate 8a. The unstable 8a delivered
8b through reductive elimination with C,C-coupling. CoX(PMe3)3 was
formed in the presence of trimethylphosphine in the solution to afford
the novel fluorinated imine as the final products 9 and 10.
In summary, we reported the C\F and C\H bond activation of
polyfluoroimine ligands induced by CoMe(PMe3)4. Four organocobalt(I)
complexes (5–8) were synthesized and characterized. The reactions of 8
with MeI and EtBr afforded organic fluorides 9–10 as C–C coupling
products. The crystal and molecular structures of complexes 5, 6 and 8
were determined by X-ray single crystal diffraction.
of 7: Complex
7 as green crystals was obtained in the yield of 53%.
Dec. N98 °C. Anal. Calc. for C22H34ClCoF2NP3 (537.82 g mol−1): C, 49.13; H,
Cl
F
Cl
Cl
Cl
F
F
F
F
N
+
RX
X
+ PMe3
N
N
N
Co PMe3
F
PMe3
PMe3
PMe3
PMe3
- PMe3
- CoX(PMe3)3
Co
F
R
Co
F
F
R
F
R
PMe3
F
F
X
Me3P
8
8a
8b
9 - 10
Scheme 2. A proposed mechanism of demetallation of complex 8.

F. Lu et al. / Inorganic Chemistry Communications 43 (2014) 110–113
113
6.37; N, 2.60%. Found: C, 49.02; H, 6.28; N, 2.74. IR (Nujol mull): 1589 ν(C_N),
945 ν(PMe3) cm−1. NMR data: 1H NMR (300 MHz, C6D6, 298 K): δ 9.43 (s, 1H,
CH = N), 7.13 (d, J = 6.0 Hz, 2H, Ar-H), 7.05 (s, 1H, Ar-H), 6.95 (d, J = 6.0 Hz,
(0.55 g, 1.00 mmol) in diethyl ether (40 mL) at −78 °C under N2 atmosphere.
The reaction mixture was warmed to ambient temperature and stirred for 24 h.
During this period, the dark green reaction mixture turned light red in color. After
filtering, crystallization from diethyl ether at 4 °C afforded blue crystals of
Co(PMe3)3Br (0.30 g, 81%) identified by IR spectra [25]. After isolation of
Co(PMe3)3Br, the solution of diethyl ether was concentrated by rotary evaporation
to provide the crude product. Further column separation provided final products
(SiO2, petroleum ether:triethylamine (200:1) as eluant). Isolated yield: 0.27 g (91
%). NMR data: 1H NMR (300 MHz, CDCl3, 298 K): δ 8.67 (s, 1H, CH = N), 7.34 (d,
J = 9.0 Hz, 2H, Ar-H), 7.11 (d, J = 9.0 Hz, 2H, Ar-H), 6.88–6.79 (m, 1H, Ar-H),
3.26–3.17 (m, 2H, CH2), 1.25 (t, J = 9.0 Hz, 3H, CH3), 19F NMR (282 MHz, CDCl3,
298 K), δ −118.4 (dd, J = 5.6, 19.7 Hz, 1F), −128.7 (dd, J = 5.6, 22.6 Hz, 1F),
−147.1 (dd, J = 14.1, 22.6 Hz, 1F). 13C NMR (75 MHz, CDCl3, 298 K): δ 158.7 (ddd,
J = 250.5, 10.5, 3.0 Hz), 154.8 (d, J = 6.0 Hz), 151.5 (dt, J = 15.0, 255.0 Hz), 150.4
(s), 145.9 (ddd, J = 3.8, 12.0, 240.0 Hz), 135.7 (d, J = 15.0 Hz), 132.0 (s), 129.3 (d,
J = 15.8 Hz), 122.0 (s), 118.5–118.4 (m), 103.2–102.6 (m), 19.2 (s), 14.3 (s). HRMS
(EI) m/z calculated for C15H11F3NCl: 297.707
2H, Ar-H), 6.73 (s, 1H, Ar-H), 1.07 (s, 18H, PCH3), 0.86 (d, J = 6.0 Hz, 9 H, PCH3), 31
P
NMR (121 MHz, C6D6, 298 K): δ −1.6 (s, 1P, PMe3), −15.5 (s, 2P, PMe3), 19F NMR
(282 MHz, C6D6, 298 K), δ −90.5 (d, J = 14.1 Hz, 1F), −124.7 (d, J = 22.6 Hz, 1F).
Synthesis of 8: Complex 8 as green crystals was obtained in the yield of 80%. Anal.
calc. for C22H33ClCoF3NP3 (555.78 g mol−1): C, 47.54; H, 5.98; N, 2.52%. Found:
C, 47.70; H, 6.07; N, 2.54. Dec. N115 °C. IR (Nujol mull): 1605 ν(C_N), 945
ν(PMe3) cm−1. NMR data: 1H NMR (300 MHz, C6D6, 298 K): δ 9.02 (s, 1H,
CH = N), 6.92 (d, J = 9.0 Hz, 2H, Ar-H), 6.70 (d, J = 9.0 Hz, 2H, Ar-H), 6.55–6.47
(m, 1H, Ar-H), 0.82 (s, 18H, PCH3), 0.60 (d, J = 6.0 Hz, 9H, PCH3), 31P NMR
(121 MHz, C6D6, 298 K): δ −1.0 (s, 1P, PMe3), −17.0 (s, 1P, PMe3), −17.2 (s, 1P,
PMe3), 19F NMR (282 MHz, C6D6, 298 K), δ −115.7 (m, 1F), −120.7 (d, J = 19.7 Hz,
1F), −140.5 (d, J = 28.2Hz, 1F). Synthesis of complex 9: A solution of MeI (0.22 g,
1.50 mmol) in diethyl ether (10 mL) was added to a solution of 8 (0.55 g,
1.00 mmol) in diethyl ether (40 mL) at −78 °C under N2 atmosphere. The reaction
mixture was warmed to ambient temperature and stirred for 24 h. During this period,
the dark green reaction mixture turned light red in color. After filtering, crystallization
from diethyl ether at 4 °C afforded violet-blue crystals of Co(PMe3)3I (0. 34 g, 82%)
identified through IR spectra [25]. After isolation of Co(PMe3)3I, the solution was
concentrated by rotary evaporation to provide the crude product. Further column
separation provided final product (SiO2, petroleum ether:triethylamine (200:1) as
eluant). Isolated yield: 0.25 g (88 %). NMR data: 1H NMR (300 MHz, CDCl3, 298 K): δ
8.70 (s, 1H, CH = N), 7.36 (d, J = 9 Hz, 2H, Ar-H), 7.12 (d, J = 9 Hz, 2H, Ar-H),
6.90–6.82 (m, 1H, Ar-H), 2.66 (d, J = 3.0 Hz, 3H, CH3), 19F NMR (282 MHz, CDCl3,
298 K), δ −119.2 (dd, J = 5.6, 14.1 Hz, 1F), −128.8 (dd, J = 5.6, 22.6 Hz, 1F),
−144.7 (dd, J = 14.1, 22.6 Hz, 1F). 13C NMR (75 MHz, CDCl3, 298 K): δ 158.6 (dd,
J = 247.5, 9.0 Hz), 154.4 (d, J = 6.0 Hz), 151.1 (dt, J = 15.0, 270.0 Hz), 150.4 (s),
146.0 (dd, J = 16.5, 240.0 Hz), 132.0 (s), 129.5 (d, J = 15.8 Hz), 129.3 (s), 122.0 (s),
118.9 (d, J = 9.0 Hz), 103.1–102.4 (m), 12.7 (s). HRMS (EI) m/z calculated for
C14H9F3NCl: 283.6802; found: 284.0456. Synthesis of complex 10: A solution of
C2H5Br (0.g, 1.50 mmol) in diethyl ether (10 mL) was added to a solution of 8
[23] Crystallographic data for 5: C28H45CoF4NP3, 623.49 g mol−1, monoclinic, space
group Pbca, a = 18.239(4) Å, b = 18.423(4) Å, c = 18.885(4) Å, V = 6346(2) Å3,
T = 293 K, Z = 8, Dc = 1.305 mg cm−3, μ = 0.733 mm−1. A total of 35691 reflec-
tions were collected, 7185 unique (Rint = 0.0718), R1 = 0.0471 (for 7185 reflec-
tions), wR2 = 0.1048(all data). Crystallographic data for 6: C22H34ClCoF2NP3,
537.79 g mol−1, orthorhombic, space group P21/n, a = 11.388(2) Å, b = 10.070(2) Å,
c = 22.960(5) Å, β = 103.10°, V = 2564.5(9) Å3, T = 293 K, Z = 4, Dc =
1.393 mg cm−3, μ = 0.985 mm−1. A total of 14799 reflections were collected, 5801
unique (Rint = 0.0239), R1 = 0.0340 (for 5801 reflections), wR2 = 0.0848
(all data). Crystallographic data for 8: C22H33ClCoF3NP3, 555.78
orthorhombic, space group P21/m, a = 11.503(2) Å, b = 10.226(2) Å, c = 11.725(2)
g ,
mol−1
Å, β = 106.24(3)°, V = 1324.2(5) Å3, T = 293 K, Z = 2, Dc = 1.394 mg cm−3
,
μ = 0.961 mm−1. A total of 7805 reflections were collected, 3154 unique
(Rint = 0.0196), R1 = 0.0354 (for 3154 reflections), wR2 = 0.0933(all data).
[24] A.R. Rossi, R. Hoffmann, Inorg. Chem. 14 (1975) 365–374.
[25] H.-F. Klein, H.H. Karsch, Inorg. Chem. 14 (1975) 473–477.