Organometallics
Article
MHz spectrometer at 135 °C, with o-C6D4Cl2 as a solvent. Mass
spectra were obtained using electron impact (EI-MS). The 19F NMR
spectra of the complexes were recorded on a Bruker 400 MHz
spectrometer. 19F NMR spectra of the complexes were recorded with
fluorobenzene as the internal standard (δF = −112.6 ppm). UV−vis
spectra were taken on a Shimadzu UV-2450 UV−vis spectropho-
tometer. Magnetic susceptibilities were measured with a SQUID
magnetometer (Quantum Design, MPMS-LS). Elemental analyses
were recorded on an elemental Vario EL spectrometer. The IR spectra
of complexes were recorded on a Bio-Rad FTS-135 spectropho-
tometer. The weight-average molecular weights (Mw) and the
polydispersity indices (PDIs) of polymer samples were determined
at 150 °C by a PL-GPC 220 type high-temperature chromatograph
equipped with three Plgel 10-μm Mixed-B LS type columns. 1,2,4-
Trichlorobenzene (TCB) was employed as the solvent at a flow rate of
1.0 mL/min. The calibration was made by polystyrene standard
EasiCal PS-1 (PL Ltd.). The 2.20 M n-butyllithium solution in hexane
was purchased from Acros. Modified methylaluminoxane (MMAO, 7%
aluminum in heptane solution) was purchased from Akzo Nobel
Chemical Inc. Commercial ethylene was directly used for polymer-
ization without further purification.
= 484 [M+]. Anal. Calcd for C27H27ClCrOP: C, 66.74; H, 5.60. Found:
C, 66.61; H, 5.65. UV−vis (hexane): 265, 306 nm. Magnetic
measurement: μeff (300 K) = 3.24 μB.
Synthesis of Chromium Complex 3d Cp[O-2,4-tBu2-6-(Ph2P)-
C6H2]CrCl. The complex was carried out according to the same
procedure as that of 3a, except that 2,4-tBu2-6-(Ph2P)C6H2OH (0.78
g, 2.0 mmol) was used in place of 6-(Ph2P)C6H4OH. Pure products
were obtained as dark green crystals (0.76 g, 70%). FT-IR (KBr,
cm−1): 3055, 2951, 2867, 1954, 1480, 1463, 1436, 1427, 1385, 1361,
1298, 1251, 1203, 1138, 1111, 1096, 1020, 1008, 998, 916, 879, 835,
814, 771, 744, 698, 654. EI-MS (70 eV): m/z = 541 [M+]. Anal. Calcd
for C31H35ClCrOP: C, 68.69; H, 6.51. Found: C, 68.54; H, 6.55. UV−
vis (hexane): 265, 306 nm. Magnetic measurement: μeff (300 K) = 3.28
μB.
Synthesis of Chromium Complex 3e Cp[O-2-F-6-(Ph2P)C6H3]CrCl.
The complex was carried out according to the same procedure as that
of 3a, except that 2-F-6-(Ph2P)C6H3OH (0.59 g, 2.0 mmol) was used
in place of 6-(Ph2P)C6H4OH. Pure products were obtained as green
crystals (0.72 g, 75%). 19F NMR (376.5 MHz, CDCl3): δ −138.6. FT-
IR (KBr, cm−1): 3055, 1596, 1464, 1438, 1315, 1296, 1256, 1232,
1179, 1095, 1063, 1020, 899, 844, 827, 776, 745, 737, 691. EI-MS (70
eV): m/z = 446 [M+]. Anal. Calcd for C23H18ClCrFOP: C, 61.69; H,
4.05. Found: C, 61.81; H, 4.01. UV−vis (hexane): 259, 349 nm.
Magnetic measurement: μeff (300 K) = 3.18 μB.
Synthesis of Chromium Complex 3f Cp[O-2-C6F5-6-(Ph2P)C6H3]-
CrCl. The complex was carried out according to the same procedure as
that of 3a, except that 2-C6F5-6-(Ph2P)C6H3OH (0.89 g, 2.0 mmol)
was used in place of 6-(Ph2P)C6H4OH. Pure products were obtained
as blue crystals (0.91 g, 76%). 19F NMR (376.5 MHz, CDCl3): δ
−162.2, −153.8. FT-IR (KBr, cm−1): 3087, 1582, 1557, 1518, 1493,
1468, 1436, 1413, 1323, 1281, 1263, 1228, 1181, 1098, 1069, 1019,
988, 904, 850, 822, 767, 755, 749, 739, 694, 654. EI-MS (70 eV): m/z
= 594 [M+]. Anal. Calcd for C29H18ClCrF5OP: C, 58.45; H, 3.04.
Found: C, 58.62; H, 2.98. UV−vis (hexane): 268, 304 nm. Magnetic
measurement: μeff (300 K) = 3.22 μB.
Synthesis of Chromium Complex 4b Cp[O-2-Ph-6-(Ph2PO)-
C6H3]CrCl. The complex was carried out according to the same
procedure as that of 3a, except that 2-Ph-6-(Ph2PO)C6H3OH (0.74
g, 2.0 mmol) was used in place of 6-(Ph2P)C6H4OH. Pure products
were obtained as blue crystals (0.76 g, 73%). FT-IR (KBr, cm−1):
3054, 2956, 1768, 1581, 1554, 1494, 1484, 1447, 1438, 1411, 1313,
1297, 1261, 1204, 1123, 1065, 1050, 1022, 998, 861, 814, 752, 726,
696. EI-MS (70 eV): m/z = 520 [M+]. Anal. Calcd for
C29H23ClCrO2P: C, 66.74; H, 4.44. Found: C, 66.91; H, 4.49. UV−
vis (hexane): 265, 334 nm. Magnetic measurement: μeff (300 K) = 3.27
μB.
Synthesis of Compounds 1a−1f and 2b−2e. Various phenoxy-
phosphine [O,P] ligands and phenoxy-phosphine oxide [O,PO]
ligands bearing different substituents on R1 and R2 positions, 2-R1-4-
R2-6-(Ph2P)C6H2OH (3a: R1 = R2 = H; 3b: R1 = Ph, R2 = H; 3c: R1 =
tBu, R2 = H; 3d: R1 = R2 = tBu; 3e: R1 = F, R2 = H; 3f: R1 = C6F5, R2 =
H) and 2-R1-4-R2-6-(Ph2PO)C6H2OH (4b: R1 = Ph, R2 = H; 4c: R1
= tBu, R2 = H; 4d: R1 = R2 = tBu; 4e: R1 = F, R2 = H) were prepared
according to literature procedures.31
Synthesis of Complexes 3a−3f and 4b−4c. Synthesis of
Chromium Complex 3a Cp[O-6-(Ph2P)C6H4]CrCl. A suspension of
CpLi (0.15 g, 2.00 mmol) in THF (10 mL) was slowly added to a
purple suspension of CrCl3(THF)3 (0.75 g, 2.00 mmol) in THF (20
mL) at 0 °C. The mixture was warmed to room temperature and
stirred overnight to get a blue solution. In another flask, a solution of
n-BuLi (2.20 M, 2.00 mmol) in hexane was added to a solution of 1a
(0.56 g, 2.00 mmol) in dried THF (20 mL) at −78 °C. The reaction
mixture was allowed to warm to room temperature and stirred for 2.5
h and then added slowly to the above reaction mixture at −78 °C. The
obtained reaction mixture was allowed to warm to room temperature
and was stirred overnight. During the reaction, the color of the
reaction mixture changes from blue to green. Next, the reaction
mixture was filtered by cannula filtration, and the filtrate was
concentrated in vacuo to about 5 mL. Then, hexane (20 mL) was
added into the system at room temperature. Green solids were
precipitated from the solution, which were isolated via filtration and
washed several times by cold hexane to yield 0.57g (66%) of complex
3a. Compounds 3b−3f and 4b−4c were prepared in similar methods.
FT-IR (KBr, cm−1): 3050, 1582, 1548, 1480, 1453, 1440, 1303, 1263,
1243, 1185, 1155, 1125, 1096, 1058, 1026, 850, 813, 744, 693. EI-MS
(70 eV): m/z = 428 [M+]. Anal. Calcd for C23H19ClCrOP: C, 64.27;
H, 4.46. Found: C, 64.13; H, 4.50. UV−vis (hexane): 267, 298 nm.
Magnetic measurement: μeff (300 K) = 3.15 μB.
Synthesis of Chromium Complex 3b Cp[O-2-Ph-6-(Ph2P)C6H3]-
CrCl. The complex was carried out according to the same procedure as
that of 3a, except that 2-Ph-6-(Ph2P)C6H3OH (0.71 g, 2.0 mmol) was
used in place of 6-(Ph2P)C6H4OH. Pure products were obtained as
dark green crystals (0.74 g, 73%). FT-IR (KBr, cm−1): 3055, 1577,
1553, 1496, 1480, 1448, 1434, 1400, 1290, 1251, 1201, 1182, 1159,
1095, 1021, 1007, 851, 822, 749, 694, 627. EI-MS (70 eV): m/z = 504
[M+]. Anal. Calcd for C29H23ClCrOP: C, 68.85; H, 4.58. Found: C,
68.98; H, 4.54. UV−vis (hexane): 253, 291 nm. Magnetic measure-
ment: μeff (300 K) = 3.12 μB.
Synthesis of Chromium Complex 4c Cp[O-2-tBu-6-(Ph2P
O)C6H3]CrCl. The complex was carried out according to the same
procedure as that for 3a, except that 2-tBu-6(Ph2PO)C6H3OH (0.70
g, 2.0 mmol) was use in place of 6-(Ph2P)C6H4OH. Pure products
were obtained as dark blue crystals (0.75 g, 75%). FT-IR (KBr, cm−1):
3088, 3058, 2978, 2939, 2897, 1575, 1552, 1483, 1460, 1437, 1407,
1386, 1350, 1291, 1264, 1198, 1185, 1166, 1121, 1051, 1022, 1010,
997, 876, 854, 813, 799, 766, 755, 730, 693. EI-MS (70 eV): m/z =
500 [M+]. Anal. Calcd for C27H27ClCrO2P: C, 64.61; H, 5.42. Found:
C, 64.77; H, 5.48. UV−vis (hexane): 266, 294 nm. Magnetic
measurement: μeff (300 K) = 3.18 μB.
Synthesis of Chromium Complex 4d Cp[O-2,4-tBu2-6-(Ph2P
O)C6H2]CrCl. The complex carried out according to the same
procedure as that for 3a, except that 2,4-tBu2-6(Ph2PO)C6H3OH
(0.81 g, 2.0 mmol) was used in place of 6(Ph2PO)C6H4OH. Pure
products were obtained as blue solids (0.88 g, 79%). FT-IR (KBr,
cm−1): 3078, 3058, 2954, 2904, 2867, 1770, 1594, 1536, 1406, 1438,
1426, 1385, 1361, 1301, 1253, 1202, 1120, 1059, 1021, 1011, 998, 916,
884, 871, 839, 807, 787, 775, 755, 726, 692. EI-MS (70 eV): m/z =
557 [M+]. Anal. Calcd for C31H35ClCrO2P: C, 66.72; H, 6.32. Found:
C, 66.54; H, 6.27. UV−vis (hexane): 266, 306 nm. Magnetic
measurement: μeff (300 K) = 3.21 μB.
Synthesis of Chromium Complex 3c Cp[O-2-tBu-6-(Ph2P)C6H3]-
CrCl. The complex was carried out according to the same procedure as
that of 3a, except that 2-tBu-6-(Ph2P)C6H3OH (0.67 g, 2.0 mmol) was
used in place of 6-(Ph2P)C6H4OH. Pure products were obtained as
dark green crystals (0.66 g, 68%). FT-IR (KBr, cm−1): 3050, 2952,
1577, 1549, 1483, 1457, 1436, 1402, 1382, 1353, 1294, 1260, 1251,
1191, 1110, 1096, 1081, 871, 844, 755, 741, 693. EI-MS (70 eV): m/z
Synthesis of Chromium Complex 4e Cp[O-2-F-6-(Ph2PO)C6H3]-
CrCl. The complex was carried out according to the same procedure as
4810
dx.doi.org/10.1021/om400517t | Organometallics 2013, 32, 4805−4812