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and 2,6-iPrC6H3[N=C(Cl)tBu][33] were prepared according to the liter- 0.07 [s, 18 H, SiMe3], 0.75 [s, 9 H, C(CH3)3], 1.21, 1.38 [d, 3JHH = 6.8 Hz,
3
ature procedures. PhPH2 and Ph2PH (Synor) were distilled from CaH2
both 6 H, CH(CH3)2], 1.32 [br. s., 4 H, ꢀ-CH2, thf], 3.08 [sept, JHH
=
thoroughly degassed in vacuo and stored under high purity nitro- 6.8 Hz, 2 H, CH(CH3)2], 3.56 [br. s., 4 H, α-CH2, thf], 6.56–7.08 [m, 18
gen. Rac-lactide (Alpha Aesar) was recrystallized twice from thf and
dried in vacuo. ε-Caprolactone (Alpha Aesar) was dried with CaH2
and condensed in vacuo prior to use. NMR spectra were recorded
with Bruker Avance DPX-400 and Bruker DPX-200 spectrometers in
CDCl3, C6D6 at 20 °C, unless otherwise stated. Chemical shifts for
H, Ar-H], 7.47–7.73 [m, 4 H, Ar-H]. 13C{1H} NMR (100 MHz, 20 °C,
C6D6): δ = 2.3 [SiMe3], 22.7 [CH(CH3)2], 25.3 [ꢀ-CH2, thf], 28.1
[CH(CH3)2], 31.6 [C(CH3)3], 41.5 [C(CH3)3], 67.9 [α-CH2, thf], 116.0 [d
J
J
CP = 105.8 Hz], 119.3 [d JCP = 28.6 Hz], 121.1, 122.2, 123.0, 123.4 [d
CP = 18.1 Hz], 125.7, 128.6, 129.2, 131.4, 131.6, 132.7 [d JCP = 9.7 Hz],
1H, 13C{1H} and 31P{1H} NMR spectra were referenced internally to 132.9 [d JCP = 9.4 Hz], 133.9 [d JCP = 8.2 Hz], 147.6 [d JCP = 13.0 Hz],
the residual solvent resonances and are reported relative to TMS. 149.1 [d, JCP = 7.6 Hz], 150.1, 156.4 [Ar-C], 175.3 [NCN]. 31P{1H} NMR
IR spectra were recorded as Nujol mulls with a “Bruker-Vertex 70”
instrument. The C, H, N elemental analyses were performed in the
microanalytical laboratory of the G. A. Razuvaev Institute of Organo-
metallic Chemistry using «Perkin–Elmer Series II CHNS/O Analyser
(162 MHz, 20 °C, C6D6): δ = 25.6. IR (Nujol, KBr) (ν, cm–1): 1665 (m),
˜
1589 (s), 1522 (s), 1394 (s), 1361 (s), 1315 (s), 1279 (s), 1256 (s), 1189
(s), 1154 (s), 1130 (m), 1109 (s), 1063 (s), 1027 (s), 1002 (s), 980 (s),
933 (w), 926 (w), 912 (m), 883 (s), 833 (s), 780 (s), 765 (s), 745 (s),
2400». GPC was carried out using chromatograph “Knauer Smart- 716 (s), 697 (s), 602 (s).
line” with Phenogel Phenomenex Columns 5u (300 × 7.8 mm) 104,
Synthesis of [{2-(Ph2P=NPh)}C6H4NC(tBu)N(2,6-MeC6H3)]Ca
105 Å and Security Guard Phenogel Column with RI and UV detect-
ors (254 nm). Mobile phase was thf, flow rate was 2 mL min–1. Col-
umns was calibrated by Phenomenex Medium and High Molecular
Weight Polystyrene Standard Kits with peak Mw from 2700 to
2 570 000 Da. The number average molecular masses (Mn) and
polydispersity index (Mw/Mn) of the polymers were calculated with
reference to universal calibration vs. polystyrene standards. Mn val-
ues of PLAs were corrected with a Mark–Houwink factor (0.58 for
PLA and 0.56 for PCL)[42] to account for the difference in hydro-
dynamic volumes between polystyrene and polylactide, polycapro-
lactone. Microstructures of PLAs were determined by homodecou-
pling 1H NMR spectroscopy at 25 °C in CDCl3 on a Bruker Avance
DPX-400 spectroscopy instrument.
[N(SiMe3)2](thf) (2): A solution of [(Me3Si)2N]2Ca(thf)2 (0.28 g,
0.55 mmol) in 30 mL of toluene was added to L2H (0.30 g,
0.55 mmol). The reaction mixture was stirred at 25 °C for 12 h. The
volatiles were removed in vacuo. After recrystallization of the solid
residue from a thf/hexane mixture complex 2 was isolated as col-
ourless crystals in 72 % yield (0.33 g). C47H63CaN4OPSi2: calcd. C
68.24, H 7.68, N 6.77; found C 68.47, H 7.43, N 6.91. 1H NMR
(400 MHz, 20 °C, C6D6): δ = 0.07 [s, 18 H, SiMe3], 0.83 [c, 9 H,
C(CH3)3], 1.37 [m, 4 H, ꢀ-CH2, thf], 2.41, 2.59 [s, both 3 H,
C6H3(CH3)2], 3.54 [m, 4 H, α-CH2, thf], 6.43–7.05 [m, 21 H, Ar-H],
7.93–8.02 [m, 1 H, Ar-H]. 13C{1H} NMR (100 MHz, 20 °C, C6D6): δ =
2.3 [SiMe3], 21.5, 22.1 [C6H3(CH3)2], 25.4 [ꢀ-CH2, thf], 29.8 [C(CH3)3],
42.5 [C(CH3)3], 67.5 [α-CH2, thf], 113.0 [d, JCP = 125.0 Hz], 112.7 [d,
Synthesis of 2-(Ph2P=NPh)C6H4NHC(tBu)=N(2,6-iPr2C6H3) (L1H):
A solution of 2,6-iPrC6H3[N=C(Cl)tBu] (3.79 g, 13.58 mmol) and Et3N
(1.37 g, 13.58 mmol) in 30 mL of toluene was added to a suspension
of 2-[Ph2P=NPh]C6H4NH2 (5.00 g, 13.58 mmol) in 20 mL of toluene.
The reaction mixture was stirred at 120 °C for 72 h and the volatiles
were removed in vacuo. White solid residue was dissolved in 200 mL
of diethyl ether and washed with aqueous solution of Na2CO3 (1 %,
3 × 100 mL). Organic layer was thoroughly separated and dried with
MgSO4. Slow concentration of the solution afforded L1H as colorless
crystals in 61 % yield (5.05 g). C41H46N3P: calcd. C 80.73, H 7.39, N,
6.95; found C 80.49, H 7.58, N, 6.87. MS (EI, 70 eV), m/z: 610.59 [M]+.
JCP = 14.8 Hz], 118.3, 120.2 [d, JCP = 8.7 Hz], 121.4, 124.7 [d, JCP
15.3 Hz], 129.0 [d, JCP = 17.0 Hz], 129.5, 130.7, 131.9 [d, JCP
=
=
12.3 Hz], 132.2, 133.7 [d, JCP = 10.6 Hz], 134.4 [d, JCP = 8.0 Hz], 148.1,
150.7 [d, JCP = 6.1 Hz], 156.8 [d, JCP = 4.1 Hz] Ar-C, 179.3 [NCN].
31P{1H} NMR (162 MHz, 20 °C, C6D6), δ: 26.4. IR (Nujol, KBr)
(ν, cm–1): 1644 (s), 1590 (s), 1542 (s), 1524 (s), 1317 (s), 1309 (s),
˜
1277 (m), 1251 (s), 1223 (m), 1182 (m), 1156 (s), 1127 (m), 1105 (s),
1078 (m), 1061 (m), 1024 (s), 989 (s), 977 (s), 930 (s), 919 (s), 881 (s),
831 (s), 819 (s), 782 (s), 765 (s).
General Procedure for Hydrophosphination Reactions: In a glass
flask in an inert atmosphere 10 mg of the complex were placed, the
calculated amount of styrene [C6H5C(Me)=CH2, PhCCH, 1,4-CH2=CH-
C6H4] and PhPH2 (Ph2PH) was added. The ampule was sealed under
vacuum and heated in an oil bath at 70 °C for 24–72 h. CDCl3
was added to the reaction mixture and poured into an NMR tube.
Conversion, chemo-, regio- and stereoselectivity was determined by
1H and 31P NMR spectroscopy.
1
M.p. 142–145 °C. H NMR (400 MHz, 20 °C, CDCl3): δ = 1.01 [m, 15
3
H, C(CH3)3, CH(CH3)2], 1.16 [d, JHH = 6.8 Hz, 6 H, CH(CH3)2], 2.71
3
3
[sept, JHH = 6.8 Hz, 2 H, CH(CH3)2], 6.70 [t, JHH = 7.1 Hz, 1 H, Ar-
3
H], 6.80–6.96 [m, 7 H, Ar-H], 7.05 [t, JHH = 7.4 Hz, 2 H, Ar-H], 7.28–
3
7.35 [m, 1 H, Ar-H], 7.45–7.54 [m, 5 H, Ar-H], 7.59 [t, JHH = 6.7 Hz,
2 H, Ar-H], 7.65–7.70 [m, 4 H, Ar-H], 10.27 [br. s, 1 H, NH]. 13C{1H}
NMR (100 MHz, 20 °C, CDCl3): δ = 21.8, 24.0 [CH(CH3)2], 28.3
General Procedure for Polymerization of rac-Lactide: In a typical
experiment (Table 6, entry 1), in a glovebox, a Schlenk flask was
charged with a solution of 1 (10 μmol) in toluene (1.0 mL). To this
solution, rac-lactide (0.144 g, 1.0 mmol, 100 equiv.) was added rap-
idly. The mixture was immediately stirred with a magnetic stir bar
at 20 °C for 12 h. After an aliquot of the crude material was sampled
by pipette for determining monomer conversion by 1H NMR, the
reaction was quenched by adding of 1.0 mL of a 10 % H2O solution
in thf, and the polymer was precipitated from CH2Cl2/pentane (ca.
2:100 mL) five times. The polymer was dried in vacuo to a constant
weight.
[CH(CH3)2], 29.1 [C(CH3)2], 41.3 [C(CH3)2], 117.6, 120.5 [d, JCP
=
24.6 Hz], 122.1, 123.2 [d, JCP = 17.8 Hz], 128.8 [d, JCP = 11.5 Hz],
132.0, 132.8 [d, JCP = 9.9 Hz] Ar-C, 135.2, 144.9, 146.0, 150.5 tert.
Ar-C, 153.4 [NCN]. 31P{1H} NMR (162 MHz, 20 °C, CDCl3): δ = 12.7. IR
(Nujol, KBr) (ν, cm–1) = 3261 (m) (N-H), 1639 (m) (C=N), 1590 (m),
˜
1570 (m), 1529 (m), 1332 (m), 1297 (m), 1262 (m), 1238 (m), 1148
(m), 1107 (m), 1078 (m), 1038 (m), 1014 (m), 997 (m), 933 (m), 889
(w), 858 (w), 823 (w), 797 (w), 782 (w), 755 (m), 708 (m), 694 (m).
Synthesis
of
[2-(Ph2P=NPh)C6H4NC(tBu)N(2,6-iPr2C6H3)]Ca
[N(SiMe3)2](thf) (1): L1H (0.28 g, 0.45 mmol) was added to a solu-
tion of [(Me3Si)2N]2Ca(thf)2 (0.23 g, 0.45 mmol) in 30 mL of toluene.
The reaction mixture was stirred at 25 °C for 12 h. The volatiles were
removed in vacuo. After recrystallization of the solid residue from a
thf/hexane mixture complex 1 was isolated as colourless crystals in
68 % yield (0.27 g). C51H71CaN4OPSi2: calcd. C 69.34, H 8.10, N 6.34;
General Procedure for Polymerization of ε-Caprolactone: In a
typical experiment (Table 5, entry 1), in a glovebox, a Schlenk flask
was charged with a solution of 1 (10 μmol) in toluene (1.0 mL). To
this solution, ε-caprolactone (0.11 mL, 1.0 mmol, 100 equiv.) was
added rapidly. The mixture was immediately stirred with a magnetic
1
found C 69.51, H 8.32, N 6.17. H NMR (400 MHz, 20 °C, C6D6): δ =
Eur. J. Inorg. Chem. 0000, 0–0
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