Molecules 2019, 24, 1502
11 of 15
3
.3. Synthesis
Synthesis of Pt-1: After degassing of DMSO (5 mL), compound L1 (180 mg, 0.5 mmol), K PtCl
2
4
(
210 mg, 0.5 mmol), and K CO (210 mg, 1.5 mmol) were added, the flask was placed under vacuum
2 3
◦
and backfilled with argon several times. Then the reaction mixture was heated to 80 C for 18 h.
The solvent was evaporated under reduced pressure at 80 C and the crude product was washed
◦
1
with water (2 × 100 mL) to give the reddish-brown product (230 mg, 83.18%). H-NMR (400 MHz,
DMSO-d6)
δ (ppm): 9.54 (s, 1H), 9.52 (s, 1H), 8.78 (s, 1H), 8.31 (d, J = 8.8 Hz, 1H), 8.04 (d, J = 8.1,
13
Hz, 1H), 7.94–7.82 (m, 2H), 7.67–7.43 (m, 2H), 7.10 (d, J = 8.3 Hz, 2H), 6.86–6.62 (m, 2H). C-NMR
101 MHz, DMSO-d6) (ppm): 164.37, 151.17, 144.79, 143.90, 136.07, 135.69, 135.37, 128.72, 122.13,
21.85, 121.22, 121.03, 120.55, 117.64, 116.29, 116.17, 115.21, 113.60, 112.19. HRMS (ESI-): m/z calcd for
(
1
δ
−
−
C H N O Pt [M − H] , 552.0522, found [M − H] , 552.0519.
21
14
2
4
Synthesis of Pt-2: The solution of compound Pt-1 (55.3 mg, 0.1 mmol) in DMF (5 mL) were
added EDC (1-(3-dimethylaminopropyl)-3-ethylcarbodiimide) (33
µ
L, 0.15 mmol) and HOBT
◦
(
1-hydroxybenzotriazole) (20.3 mg, 0.15 mmol), and the mixture was stirred at
−20 C for 3 h. Then
A
A
compound 6 -amino-6 -deoxy-β-CD (136 mg, 0.12 mmol, 1.2 equiv.) was added, and the mixture was
stirred at room temperature for another 6 h. After completion of the reaction, the mixture was dropwise
added into acetone (200 mL) to obtain the crude product as a red precipitate, which was purified by
reverse phase chromatography, using ethanol aqueous solution in gradient elution from 0–50% to afford
1
the product as red solid (45.6 mg, 27.32%). H-NMR (400 MHz, DMSO-d )
δ
(ppm): 9.51 (d, J = 6.8 Hz,
6
2
H), 8.84 (s, 1H), 8.53–8.39 (m, 2H), 7.86 (d, J = 9.1 Hz, 3H), 7.59 (d, J = 6.1 Hz, 2H), 7.12 (d, J = 8.6 Hz,
H), 6.81 (d, J = 7.0 Hz, 2H), 5.79 (d, J = 18.8 Hz, 14H), 5.14–4.68 (m, 7H), 4.49 (t, J = 36.1 Hz, 7H), 4.08
(ppm):
2
(
d, J = 7.2 Hz, 1H), 3.94–3.80 (m, 1H), 3.63 (d, J = 26.2, 40H). 13C-NMR (151 MHz, DMSO-d6)
δ
1
1
65.53, 165.26, 165.09, 152.34, 152.11, 146.86, 144.74, 136.35, 136.29, 136.12, 133.96, 127.18, 122.43, 122.35,
21.82, 121.71, 116.98, 116.63, 116.23, 102.77, 102.41, 102.03, 84.83, 82.10, 81.93, 81.76, 81.70, 73.51, 73.44,
7
2.89, 72.76, 72.62, 72.56, 72.48, 72.39, 70.35, 60.59, 60.42, 60.34, 60.23, 59.86. MALDI-TOF-HRMS: m/z
+
+
calcd for C H N O Pt M, 1668.4353, [M + H] , 1669.4431; found [M + H] , 1669.4962.
63
83
3
37
Synthesis of Pt-3: The synthesis procedure is the same as Pt-2. 1H-NMR (400 MHz, DMSO-d6)
ppm): 9.50 (s, 2H), 8.81 (s, 1H), 8.44 (d, 1H), 7.86 (d, J = 8.0 Hz, 3H), 7.56 (s, 2H), 7.11 (d, J = 8.7 Hz,
H), 6.77 (t, 2H). 13C-NMR (151 MHz, DMSO-d6)
(ppm): 165.68, 165.20, 165.04, 146.84, 144.64, 136.31,
δ
(
2
δ
1
6
33.84, 122.35, 121.72, 117.01, 116.61, 116.02, 102.86, 102.18, 101.94, 81.48, 81.04, 80.51, 73.05, 72.80, 72.56,
+
0.36, 56.43. MALDI-TOF-HRMS: m/z calcd for C H N O Pt [M], 1830.4881, [M + Na] , 1853.4779,
69
93
+
3
42
+
+
+
[M + K] , 1869.4518, found M , 1830.4833, [M + Na] , 1853.4727, [M + K] , 1869.4523.
4
. Conclusions
In conclusion, a new
driven photocatalytic supramolecular enantiodifferentiating dimerization of 2-anthracenecarboxylic acid
AC) through triplet-triplet annihilation. The photoreaction mediated with Pt-2 failed to form irregular
β
-CD based sensitizer/host Pt-2 was synthesized and was applied for visible-light-
(
0
0
chiral slipped 5, 8: 9 , 10 -cyclodimers due to aggregation of Pt-2 in water, thus hard to form the 2:2 complex
with AC. Decreasing the concentration of sensitizers/hosts significantly enhanced the enantioselectivities of
the optical photodimers 2 and 3 when employing Pt-2, and Pt-3 as the hosts as well as the sensitizers, and
was triggered by 532 nm laser, making them good candidates for organic photocatalyst. The photolysis of
AC through triplet-triplet annihilation sensitized by Pt-3 displayed significant temperature dependency,
the ee value of photodimer
2
was enhanced from 2.1% to 31.6% when increasing the temperature from
◦
◦
0
C to 30 C in the presence of 5% equivalent of the photocatalyst. This is unprecedented as for traditional
enantiodifferentiating photodimerization of AC, the enantioselectivity was deduced with the increasing
temperature. This work presents a new strategy for catalytic supramolecular photochirogenesis, and
provides a more comprehensive understanding for photochirogenesis through triplet-triplet annihilation.