Formation of [11]ane-P2CNHC Macrocycles
A R T I C L E S
ppm. IR (KBr): ν ) 2029 (s, CO), 1930 (s, CO), 1897 (s, CO),
1879 cm-1 (s, CO). MS (MALDI, positive ions): m/e (%): 814 (30)
(calcd [3]+ 814.0288), 786 (100) (calcd [3 - CO]+ 786.0339).
Synthesis of [5]. A solution of [ReCl(CO)5] (720 mg, 2.0 mmol)
and H2NCH2CH2NdPPh3 (640 mg, 2.0 mmol) in THF (20 mL)
was stirred for 24 h. After removal of the solvent the crude product
was purified by column chromatography (dichloromethane, SiO2)
yielding a colorless powder. Yield: 670 mg (1.66 mmol, 83%). 1H
(400.1 MHz, CDCl3): δ ) 6.90 (s, br, 2H, NH), 3.72 ppm (s, 4H,
NCH2CH2N). 13C{1H} NMR (100.6 MHz, CDCl3): δ ) 193.6
(NCN), 186.8 (CO), 184.9 (CO), 184.7 (CO), 44.2 ppm
(NCH2CH2N). IR (KBr): ν ) 3429 (s, NH), 3265 (s, br, NH), 2107
(s, CO), 2016 (s, CO), 1993 (s, br, CO), 1924 cm-1 (s, br, CO).
MS (ES, positive ions): m/e (%): 426.9455 (100) (calcd [5 + Na]+
426.9457).
observed intensities. Isomer I (abundance 40%): 1H (400.1 MHz,
CD3CN): δ ) 7.20 (s, 2H, NH), 3.60 ppm (s, 4H, NCH2CH2N).
13C{1H} NMR (100.6 MHz, CD3CN): δ ) 203.6 (NCN), 196.6
(CO), 196.0 (CO), 192.1 (CO), 45.8 ppm (NCH2CH2N). Isomer II
(abundance 60%): 1H (400.1 MHz, CD3CN): δ ) 7.06 (s, 2H, NH),
3.56 ppm (s, 4H, NCH2CH2N). 13C{1H} NMR (100.6 MHz,
CD3CN): δ ) 208.6 (NCN), 200.0 (CO), 196.2 (CO), 45.8 ppm
(NCH2CH2N). IR (KBr): ν ) 3378 (w, br, NH), 2004 (s, CO), 1895
(s, CO), 1849 cm-1 (s, CO). MS (MALDI, negative ions): m/e (%):
411 (100) (calcd [9]- 410.9303).
Synthesis of [8]Cl. A suspension of [H2-6]Cl (280 mg, 0.31
mmol) in THF (5 mL) was treated dropwise with a solution of
KOtBu (12.5 mL of a 0.05 M solution, 0.62 mmol). A clear solution
was obtained after the addition. This solution was stirred at ambient
temperature for 5 d. During this period a solid had formed which
was isolated by filtration and dissolved in dichloromethane.
Insoluble solids were separated by filtration. Complex [8]Cl was
obtained as a pale yellow solid after removal of the solvent. Yield:
Reaction of Complex [5] with 2 in Benzene or Toluene. This
reaction afforded a mixture of compounds [H2-6]Cl, [H-7]Cl, and
[8]Cl in varying relative amounts. Typically a solution of [5] (150
mg, 0.40 mmol) and 2 (210 mg, 0.40 mmol) in benzene (20 mL)
was heated under reflux for 10 h. After cooling to ambient
temperatures, the formed white precipitate was isolated by filtration
and washed with diethyl ether (2 × 10 mL). This solid contained
a mixture of compounds. The NMR and mass spectra were collected
using this mixture of compounds. 31P{1H} NMR (162.0 MHz,
1
240 mg (0.28 mmol, 91%). H (400.1 MHz, CD3CN, assignment
of the signals see Scheme 4): δ ) 7.83 (m, 2H, Ar-H5), 7.81 (m,
2H, Ar-H4), 7.69 (m, 2H, Ar-H17), 7.66 (m, 2H, Ar-H9), 7.63
(m, 2H, Ar-H14), 7.39 (m, 2H, Ar-H16), 7.38 (m, 2H, Ar-H15),
7.37 (m, 2H, Ar-H8), 7.25 (t, 2H, Ar-H10), 6.97 (m, 2H,
Ar-H11), 4.61 (m, 2H, N-CHH-CHH-N), 3.15 ppm (m, 2H,
N-CHH-CHH-N). 13C{1H} NMR (100.6 MHz, CD3CN, assignment
of the signals see Scheme 4): δ ) 193.4 (br, COtrans-C1), 192.3 (t,
2JC,P ) 13.8 Hz, C1), 191.1 (m, 2JC,P-trans ) 46.0 Hz, COcis-C1), 164.4
3
CD3CN): δ ) 21.8 (d, JP,F ) 14.7 Hz, [H2-6]+), 20.5 and 18.2
(br, [H-7]+), 15.8 ppm (d, 3JP,F ) 16.6 Hz, [8]+). 19F NMR (376.5
MHz, CDCl3): δ ) -95 (br, Ar-F), -96 (br, Ar-F), -98 (Ar-F),
-153 ppm (BF4-). MS (ES, positive ions): m/e: 859 (calcd [H2-
6]+ 859.0909)), 839 (calcd [H-7]+ 839.0852), 819 (calcd [8]+
819.0784).
1
2
2
(dd, JC,F ) 249 Hz, JC,P ) 5.0 Hz, C7), 145.8 (d, JC,P ) 11.8
Hz, C13), 139.9 (m, Ar-C3), 136.6 (d, 3JC,F ) 9.2 Hz, C9), 136.2
(m, C4), 134.7 (d, 2JC,P ) 1.6 Hz, C17), 134.6 (m, C5), 134.3 (m,
C11) 131.2 (d, 4JC,P ) 1.6 Hz, C15), 127.4 (d, 3JC,P ) 8.3 Hz, C16),
Synthesis of [H2-6]Cl. A solution of complex [5] (150 mg, 0.37
mmol) and ligand 2 (250 mg, 0.48 mmol) in acetonitrile (5 mL)
was heated under reflux for 6 h. After cooling to ambient
temperature the solvent was almost completely removed and diethyl
ether (20 mL) was added to the oily residue. Complex [H2-6]Cl
precipitated and was isolated by filtration. Yield: 330 mg (0.36
126.8 (m, C10), 125.6 (d, 3JC,P ) 6.3 Hz, C14), 123.8 (dd, 1JC,P
56.4 Hz, 4JC,F ) 4.9 Hz, C12), 117.8 (dd, 2JC,F ) 21.9 Hz, 3JC,P
)
)
4.2 Hz, C8), 115.1 (dd, 1JC,P ) 54.6 Hz, 2JC,F ) 17.7 Hz, C6), 52.4
ppm (C2). 31P{1H} NMR (162.0 MHz, CD3CN): δ ) 15.8 ppm (d,
3JP,F ) 16.6 Hz). 19F NMR (376.5 MHz, CD3CN): δ ) -97.4 ppm
(m). IR (KBr): ν ) 2031 (s, CO), 1963 (s, CO), 1937 cm-1 (s,
CO). MS (ES, positive ions): m/e (%): 819.0770 (100) (calcd [8]+
819.0784).
1
mmol, 98%). H (400.1 MHz, CD3CN, assignment of signals see
Scheme 4): δ ) 8.02 (m, 2H, Ar-H4), 7.88 (m, 2H, Ar-H5), 7.67
(m, 2H, Ar-H15), 7.44 (m, 2H, Ar-H9), 7.39 (m, 2H, Ar-H16),
7.32 (m, 2H, Ar-H17), 7.27 (m, 2H, Ar-H14), 7.16 (m, 2H,
Ar-H10), 7.10 (m, 2H, Ar-H8), 6.92 (m, 2H, Ar-H11), 6.56 (s,
2H, NH), 3.21 ppm (s, 4H, H2). 13C{1H} NMR (100.6 MHz,
CD3CN, assignment of signals see Scheme 4): δ ) 191.0 (dd, 2JC,P-
Synthesis of [10]. Complex [10] was isolated from a reaction
of [H2-6]Cl with KOtBu as described for the synthesis of [8]Cl.
After one day a solid had formed which was isolated by filtration.
The solid contained both compounds [8]Cl and [10]. This solid
was dissolved in dichloromethane and the solvent was slowly
evaporated. From this solution block shaped crystals of [8]Cl and
prisms of [10] crystallized. Attempts to separate the two compounds
led invariably to the conversion of [10] into [8]Cl.
Synthesis of [11]. A mixture of [8]Cl (340 mg, 0.40 mmol) and
Me3NO·2H2O (46 mg, 0.42 mmol) in dichloromethane (10 mL)
was stirred for 24 h. The precipitate formed was separated by
filtration and washed with ethanol (10 mL). After drying in Vacuo
complex [11] was obtained as a bright yellow solid. Yield: 245
mg (0.30 mmol, 75%). The poor solubility of [11] in common
organic solvents prevented its 1H and 13C NMR spectroscopic
characterization. 31P{1H} NMR (162.0 MHz, CD2Cl2): δ ) 30.9
(s, Cl trans to carbene), 27.9 and 25.5 ppm (m, Cl cis to carbene).
IR (KBr): ν ) 1941 (s, CO), 1878 cm-1 (s, CO). MS (MALDI,
positive ions): m/e (%): 826 (100) (calcd [11]+ 826.0520), 770 (57)
(calcd [11 - 2CO]+ 770.0621).
2
trans ) 50.4 Hz, JC,P-cis ) 8.2 Hz, COcis-C1), 190.0 (m, br, COtrans-
2
1
C1), 189.8 (t, JC,P ) 9.8 Hz, C1), 164.5 (d, JC,F ) 249 Hz, C13),
1
2
1
163.4 (dd, JC,F ) 247 Hz, JCP ) 4.9 Hz, C7), 139.2 (dd, JC,P
48.5 Hz, 2JC,P ) 33.4 Hz, C3), 136.8 (dd, 2JC,P ) 14.0 Hz, 3JC,P
)
)
2.5 Hz, C4), 136.8 (m, C17), 136.6 (dd, 3JC,F ) 9.5 Hz, 4JC,P ) 2.0
3
4
Hz, C15), 134.9 (dd, JC,F ) 8.5 Hz, JC,P ) 1.6 Hz, C9), 134.8
3
4
(dd, JC,P ) 6.2 Hz, JC,P ) 2.2 Hz, C5), 133.0 (m, C11), 126.5
3
4
3
(dd, JC,P ) 11.2 Hz, JC,F ) 3.0 Hz, C16), 125.6 (dd, JC,P ) 8.3
4
1
2
Hz, JC,F ) 3.0 Hz, C10), 122.2 (ddd, JC,P ) 53 Hz, JC,F ) 17
4
2
3
Hz, JC,P ) 2.0 Hz, C6), 118.2 (dd, JC,F ) 23.8 Hz, JC,P
)
)
1
2
4
3.4 Hz, C14), 117.3 (ddd, JC,P ) 45 Hz, JC,F ) 16.4 Hz, JC,P
2.8 Hz, C12), 117.0 (dd, 2JC,F ) 23.0 Hz, 3JC,P ) 3.7 Hz, C8), 45.9
ppm (C2). 31P{1H} NMR (162.0 MHz, CD3CN): δ ) 21.8 ppm (d,
3JP,F ) 14.7 Hz). 19F NMR (376.5 MHz, CD3CN): δ ) -97.6,
-100.3 ppm. IR (KBr): ν ) 3460 (w, NH), 2043 (s, CO), 1971 (s,
CO), 1949 (s, CO). MS (ES, positive ions): m/e (%): 859.0893
(100) (calcd [H2-6]+ 859.0909).
Synthesis of [12]. Complex [12] was prepared as described
for [5]14,16b from [MnBr(CO)5] (550 mg, 2.0 mmol) and
H2NCH2CH2NdPPh3 (640 mg, 2.0 mmol) in THF (20 mL) and
was obtained as a yellow solid. Yield: 65%. 1H (400.1 MHz,
CDCl3): δ ) 6.95 (s, br, 2H, NH), 3.80 ppm (s, 4H, NCH2CH2N).
13C{1H} NMR (100.6 MHz, CDCl3): δ ) 219.7 (NCN), 212.6 (CO),
212.1 (CO), 210.8 (CO), 45.7 ppm (NCH2CH2N). IR (KBr): ν )
3451 (w, NH), 3388 (m, NH), 3363 (m, NH), 2092 (m, CO), 1993
(s, CO), 1949 (s, br, CO), 1935 cm-1 (s, br, CO).
Synthesis of [H2-6][9]. A solution of [5] (165 mg, 0.41 mmol)
and 2 (275 mg, 0.53 mmol) in tetrahydrofuran (5 mL) was heated
under reflux for 2 h. After cooling to ambient temperature the
mixture was concentrated and diethyl ether (20 mL) was added.
Compound [H2-6][9] was subsequently isolated by filtration. Yield:
240 mg (0.19 mmol, 92%). Notice the spectroscopic data of [H2-
6]+ are identical in both salts [H2-6]Cl reported above and [H2-
6][9]. Reported here are only the data for the two isomers (fac and
mer,cis) of the anion [9]-. The assignment was based on the
9
J. AM. CHEM. SOC. VOL. 131, NO. 1, 2009 315