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quently cooled to room temperature. Deionized H O (5 mL) and
sure and the residue recrystallized from cold DCM/MeOH to give
2
1
one drop of conc. H SO was added, such that the aqueous layer
cis-[Pt(h -N C(O)PhN-benzotriazene-4-one)(Cl)(PPh ) ] (cis-5) as an
2
4
2
3 2
1
was acidic by litmus. The organic layer was separated and the
aqueous layer was washed with ethyl acetate until almost color-
less. The organic extracts were combined, dried with brine and an-
off-white solid (30.4 mg, 0.030 mmol, 70%). H NMR (400 MHz,
CDCl ): d=11.08 (s, NH), 8.47 (d, 1H, J=8.4 Hz), 8.37 (d, 1H, J=
3
7.6 Hz), 8.06 (t, 1H, 7.6 Hz), 7.86 (t, 1H, J=7.6 Hz), 7.76 (t, 1H, J=
hydrous MgSO , and the solvent removed under reduced pressure
6.8 Hz), 7.60–7.49 (m, 4H), 7.48–7.39 (m, 4H), 7.24–7.10 (m, 12H),
4
3
1
to give red-orange solids. The solids were washed with 20 mL
6.95 (t, 1H, J=6.8 Hz), 6.70 ppm (t, 1H, J=7.6 Hz); P NMR
(162 MHz, CDCl3): d=20.73 (d,J(P,P)=16.2 Hz; Pt satellites, d,
J(Pt,P)=1722 Hz), 15.24 ppm (d, J(P,P)=16.2 Hz; Pt satellites, d,
J(Pt,P)=4484 Hz); IR (KBr): n˜ =3053 (m), 2920 (w), 1717 (svs), 1687
(s), 1644 (m), 1603 (w), 1577 (m), 1481 (m), 1458 (m), 1435 (vs),
1326 (w), 1305 (m), 1264 (m), 1228 (m), 1181 (w), 1153 (w), 1096 (s),
1060 (m), 1024 (m), 919 (w), 886 (w), 776 (m), 736 (s), 693 (vs), 544
1
EtOH to give 3 as an insoluble orange solid (0.0327 g). H NMR
(
500 MHz, [D ]DMF): d=16.22 (sbr, NH), 12.79 (sbr, NH), 8.57 (d,
7
1
1
H, J=8 Hz), 8.51 (d, 1H, J=8 Hz), 8.43 (d, 1H, J=7.5 Hz), 8.39 (d,
H, J=8 Hz), 8.32–8.27 (m, 2H), 8.12 (t, 1H, J=7.5 Hz), 7.93–7.89
(
(
[
m, 2H), 7.74 (d, 1H, J=7.5 Hz), 7.64 (t, 1H, J=7.5 Hz), 7.54–7.48
m, 2H), 6.66 ppm (d, 1H, J=9.5 Hz); H NMR (500 MHz,
D ]DMSO): d=16.07 (s, NH), 12.72 (s, NH), 8.59 (d, 1H, 12.5 Hz),
6
1
À1
(m), 524 (vs), 498 cm (m).
8
(
.41–8.38 (m, 3H), 8.24 (t, 1H, J=8 Hz), 8.14 (d, 1H, J=7 Hz), 8.08
t, 1H, J=7.5 Hz), 7.89–7.84 (m, 2H), 7.70 (d, 1H, 7.5 Hz), 7.60 (t,
Thermodynamic product trans-5:
1
H, J=7 Hz), 7.50–7.46 (m, 2H), 6.62 ppm (d, 1H, J=9.5 Hz);
1
3
2
C NMR (126 MHz, [D ]DMF): d=176.76, 166.70, 153.36, 44.69,
Pt(h -N
C(O)PhN-benzotriazene-4-one)(PPh
2
) (42 mg, 0.043 mmol)
3 2
7
1
1
1
43.72, 142.08, 136.20, 134.20, 133.72, 133.59, 131.10, 129.47,
29.25, 129.15, 128.96, 128.80, 126.99, 126.22, 125.41, 125.26,
was dissolved in dry CHCl
3
(5 mL) and DMA·HCl (6 mg,
0.049 mmol) was added. A white suspension formed immediately,
which dissolved when the reaction was heated at reflux for 1 h to
give a yellow solution. The solvent was removed under reduced
1
3
22.34, 120.99, 119.11, 117.23 ppm; C NMR (126 MHz, [D ]DMSO):
6
d=177.30, 166.66, 153.50, 144.25, 143.63, 142.80, 136.87, 134.80,
1
1
34.29, 133.52, 131.09, 130.02, 129.69, 129.49, 129.27, 128.74,
27.53, 126.51, 125.80, 125.67, 122.59, 120.80, 118.69, 117.48 ppm;
pressure and the residue recrystallized from DCM/MeOH to give
1
trans-[Pt(h -N
C(O)PhN-benzotriazene-4-one)(Cl)(PPh
)
] (trans-5) as
2
3
2
1
IR (KBr): n˜ =3432 (vs), 2964 (m), 1691 (s), 1657 (s), 1623 (s), 1573
a pale yellow solid (37 mg, 0.036 mmol, 85% yield). H NMR
(400 MHz, CDCl ): d=12.66 (s, NH), 8.27 (d, 1H, J=8 Hz), 8.20 (d,
1H, J=7.6 Hz), 8.02 (t, 1H, J=7.2 Hz), 7.82 (t, 1H, J=7.6 Hz), 7.75–
7.63 (m, 12H, PPh ) 7.42 (d, 1H, J=8 Hz), 7.36 (t, 1H, J=7.2 Hz),
7.34–7.22 (m, 18H, PPh ), 6.54 (t, 1H, J=7.2 Hz), 6.37 ppm (t, 1H,
J=7.2 Hz); P NMR (162 MHz, CDCl ): d=22.79 ppm (s; Pt satel-
lites, d, J(Pt,P)=2884 Hz); IR (KBr): n˜ =3052 (m), 1966 (vw), 1890
vw), 1809 (vw), 1711 (s), 1687 (s), 1640 (m), 1627 (m), 1579 (m),
481 (m), 1459 (m), 1435 (vs), 1329 (m), 1256 (m), 1222 (m), 1186
(
(
(
m), 1495 (s), 1480 (s), 1445 (s), 1400 (m), 1320 (m), 1293 (w), 1260
vs), 1195 (s), 1093 (vs), 1024 (vs), 841 (m), 798 (vs), 747s, 685 cm
w); MS (ESI): 475.09108 [M+K] ; elemental analysis calcd (%) for
3
À1
+
3
C H N O (436.43): C 65.98, H 3.67, N 19.24; found: C 60.41, H
3
3
24
16
6
3
31
.80, N 16.97.
3
(
1
Reaction of 2 with [Pt(PPh ) ]
3
4
[
(
Pt(PPh ) ] (100 mg, 0.08 mmol) and bis(benzotriazene-4-one)
(w), 1156 (w), 1096 (s), 1129 (m), 999 (m), 920 (m), 891 (w), 787 (m),
774 (m), 743 (m), 708 (s), 693 (vs), 619 (w), 540 (w), 499 cm (s); el-
3
4
À1
23.5 mg, 0.12 mmol) were charged into a 50 mL flask under N at-
2
mosphere. Dry CH CN (10 mL) was added and the reaction mixture
emental analysis calcd (%) for C H N O P ClPt·0.7CH Cl (1079.83)
3
50 39
4
2
2
2
2
protected from light and heated at reflux for 2 h. The solvent was
removed under reduced pressure and the reaction residue recrys-
tallized from dichloromethane/methanol mixture to give [Pt(h -
C 56.39, H 3.77, N 5.19; found: C 56.16, H 3.61, N 5.54.
2
Theoretical calculations
N C(O)PhN-benzotriazene-4-one)(PPh ) ] (4) as a very pale yellow
2
3 2
1
solid (60 mg, 0.061 mmol, 76%). H NMR (400 MHz, CDCl ): d=8.47
DFT calculations were performed with the Gaussian 03 program by
using the B3LYP functional and 6-311+ +G** basis sets. The C
2
ground-state structure corresponds to a local minimum with all-
positive vibrational modes; the C2v and C2h transition states were
located by the quadratic synchronous transit algorithm, which was
then checked with an internal reaction coordinate calculation to
3
(
7
d, 1H, J=7.2 Hz), 8.32 (d, 1H, J=7.6 Hz), 8.09 (t, 1H, J=7.2 Hz),
.95 (t, 1H, J=8 Hz), 7.93 (t, 1H, J=7.6 Hz), 7.75–7.60 (m, 8H,
PPh ), 7.49 (t, 1H, J=8 Hz), 7.36–7.27 (m, 3H, PPh ), 7.23–7.09 (m,
3
3
1
0H, PPh ), 7.00–6.91 (m, 4H, PPh ), 6.91–6.80 (m, 5H, PPh ), 6.72
3 3 3
3
1
(
m, 1H), 6.58 ppm (m, 1H); P NMR (162 MHz, CDCl ): d=21.34 (d,
3
J(P,P)=15.4 Hz; Pt satellites, d, J(Pt,P)=2042 Hz), 18.49 ppm (d,
J(P,P)=15.4 Hz; Pt satellites, d, J(Pt,P)=3894 Hz); IR (KBr): n˜ =3052
ensure that the transition state led to the two racemic C products.
2
For crystallographic information and details of the theoretical cal-
culations, see the Supporting Information
(
w), 2924 (vw), 1704 (s), 1644 (vs), 1583 (m), 1480 (m), 1461 (m),
1
1
435 (s), 1315 (m), 1291 (m), 1263 (m), 1185 (w), 1125 (w), 1093 (s),
027 (m), 998 (m), 921 (w), 774 (m), 738 (s), 696 (vs), 541 (s), 510
À1
(
s), 501 cm
(s); elemental analysis calcd (%) for Acknowledgements
C H N O P Pt·0.65CH Cl (1079.83): C 58.55, H 3.81, N 5.39; found:
50
38
4
2
2
2
2
C 58.22, H 3.96, N 5.72.
We gratefully acknowledge NSERC and the CRC for support of
this research.
2
Reaction of Pt(h -N C(O)PhN-benzotriazene-4-one)(PPh ) (4)
2
3 2
with DMA·HCl Kinetic product cis-5:
Keywords: azo compounds
rearrangement · nitrogen · ring opening
·
catenation
·
Dimroth
2
Pt(h -N C(O)PhN-benzotriazene-4-one)(PPh ) (21 mg, 0.022 mmol)
2
3 2
and DMA.HCl (3 mg, 0.025 mmol) was dissolved in cold, dry CH Cl2
2
(
8 mL) at À788C and stirred for 10 min before allowing the reac-
[
1] F. R. Benson, The High Nitrogen Compounds, John Wiley and Sons, New
York, 1984.
tion mixture to reach room temperature. A white suspension
formed initially, which dissolved gradually when the reaction tem-
perature increased. The solvent was removed under reduced pres-
[2] F. A. Cotton, G. Wilkinson, Advanced Inorganic Chemistry, 4th ed., Wiley
Interscience, New York, 1980.
Chem. Eur. J. 2015, 21, 13739 – 13747
13746
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