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D.S. Kopchuk et al. / Polyhedron 110 (2016) 235–240
Table 1
Elemental analysis (calcd): C 86.68; H 5.24; N 8.09. Found: C,
86.52; H, 5.11; N, 7.88 (see Tables 2 and 3).
Selected bond lengths for cadmium complexes 1–3.
1
2
3
2.2.1. Complex 2
Bond
Å
Bond
Å
Bond
Å
A crystal sample of cadmium complex 3 suitable for X-ray
structural analysis was obtained by slow evaporation of solution
of ligand (20 mg) and CdI2 (21 mg, 1 eq.) in acetonitrile (5 ml).
Off-white crystals. C52H36Cd2I4N4. Elemental analysis (calcd): C,
43.09; H, 2.50; N, 3.87. Found: C, 42.99; H, 2.69; N, 3.77. CCDC
1438670 contains the supplementary crystallographic data for this
complex.
Cd1 N1
Cd1 N2
Cd1 N3
Cd2 I1
Cd2 I2
Cd2 I3
2.277(5)
2.427(5)
2.358(6)
2.8581(8)
2.7195(8)
2.7004(8)
Cd1 N2
Cd1 N1
Cd1 I2
Cd2 I2
I1 Cd2
2.287(6)
2.491(5)
3.0585(7)
2.8486(7)
2.7372(8)
Cd1 N1
Cd1 N3
Cd1 N2
Cd1 N4
Cd1 I1
Cd1 I2
I1 Cd2
Cd2 I3
Cd2 I4
2.318(6)
2.321(6)
2.481(6)
2.484(6)
2.9831(11)
2.9837(10)
2.774(4)
2.763(5)
2.619(9)
2.2.2. 3,4-Diphenyl-1-(2-pyridyl)isoquinoline 6
Yield 68%. C26H18N2. M.p. 182–184 °C. NMR 1H (CDCl3, d, ppm):
7.07–7.24 (m, 3H), 7.26–7.34 (m, 2H), 7.35–7.51 (m, 6H), 7.59 (m,
2H), 7.71 (m, 1H), 7.91 (ddd, 1H, 3J 7.8, 7.8 Hz, 4J 1.8 Hz, H-40), 8.16
(d, 1H, 3J 7.8 Hz), 8.72 (m, 1H), 8.81 (dd, 1H, 3J 4.8 Hz, 4J 1.6 Hz, H-
60). NMR 13C (CDCl3, d, ppm): 123.2, 125.4, 125.6, 126.0, 127.1,
127.4, 127.5, 127.6, 127.7, 128.3, 130.1, 130.5, 131.1, 131.3,
137.0, 137.3, 137.5, 140.9, 148.5, 149.4, 156.7, 158.7. ESI-MS, m/
z: found 359.15, calculated 359.15 (M+H)+. Elemental analysis
(calcd): C 87.12, H 5.06, N 7.82. Found, %: C 86.92, H 4.88, N 7.51.
2.1. General procedure for the preparation of isoquinolines 4,6
Mixture of corresponding 5,6,7,8-tetrahydroisoquinoline [13]
(0.5 mmol), DDQ (114 mg, 0.5 mmol) and o-xylene (40 ml) was
refluxed for 3 h. Second portion of DDQ (114 mg, 0.5 mmol) was
added and the resulting mixture was refluxed for 3 h. Then third
portion of DDQ (114 mg, 0.5 mmol) was added and the resulting
mixture was refluxed for 4 h. Solvent was removed under reduced
pressure, the residue was purified by column chromatography
(neutral Al2O3, chloroform).
2.2.3. Complex 3
A crystal sample of cadmium complex 2 suitable for X-ray
structural analysis was obtained by slow evaporation of solution
of ligand (20 mg) and CdI2 (26 mg, 1 eq.) in acetonitrile (5 ml).
Off-white crystals. C50H36Cd2I4N4. Elemental analysis (calcd): C,
42.13; H, 2.55; N, 3.93. Found: C, 42.21; H, 2.33; N, 3.78. CCDC
1438669 contains the supplementary crystallographic data for this
complex.
2.1.1. 3-Phenyl-1-(2-pyridyl)isoquinoline 4
Yield 51%. C20H14N2. M.p. 107–109 °C. NMR 1H (CDCl3, d, ppm):
7.43 (m, 3H, Ph), 7.52 (m, 2H, isoquin.), 7.58 (v, 1H, isoquin.), 7.69
(m, 1H, isoquin.), 7.94 (m, 2H, Ph), 8.15 (s, 1H, H-4), 8.22 (m, 2H,
py), 8.75 (d, 1H, 3J = 8.4 Hz, py), 8.81 (d, 1H, 3J = 4.8 Hz, H-6’
(Py)). NMR 13C (CDCl3, d, ppm): 117.0, 123.2, 125.6, 127.0, 127.4,
127.5, 128.0, 128.5, 128.6, 128.8, 130.1, 137.0, 138.2, 139.5,
148.3, 149.8, 157.0, 158.8. ESI-MS, m/z: found 283.12, required
283.12 (M+H)+. Elemental analysis (calcd): C 85.08, H 5.00, N
9.92. Found, %: C 84.81, H 4.80, N 9.61.
3. Results and discussions
The ligands used for the preparation of cadmium complexes
were synthesized according to the previously reported [13,14]
‘‘1,2,4-triazine” methodology (Scheme 1). Thus, the aza-Diels–
Alder reaction between 1,2,4-triazines and 1-morpholinocy-
cloalkenes allows to obtain corresponding cycloalkene-annelated
2,20-bipyridine ligands. For the synthesis of ligands 4 and 6 the
aromatization of cyclohexane cycle was carried out by means of
DDQ, and cyclopentane-anneleted ligand 5 has been used as is.
Looking at the structures of the ligands 4–6 one can suggest that
the main differences between these ligands implies the phenyl ring
in position 3 in the isoquinoline ring or, in case of ligand 5, in an
alpha-position with reference to a nitrogen atom: in ligand 4 this
phenyl ring is free to rotate; in ligand 5 the phenyl ring is fused
to the one in position 4; and in ligand 6 it may show a preferred
disposition due to the presence of the phenyl ring in position 4.
One can suggest that these structural features of the herein
reported ligands would affect their chelating properties toward
metal cations, for instance Zn(II) or Cd(II) cations, as well as the
geometry of the coordination node.
To confirm our suggestion, at the next step Cd(II) complexes
1–3 of poly(aza)annelated analogs of 2,20-bipyridine ligands 4–6
were prepared according to reported procedures (See Section 2).
According to X-ray data, compound 1 with the [Cd(Het)2
(C2H3N)2]2+[Cd2I6]2ꢁ composition crystallizes in the centrosym-
metric system space group C2/c (Fig. 1). The chelated cation is
located in a special position with cadmium atom on the axis of
order 2 (Fig. 1). The ball-and-stick model was selected for the
graphical representation of the structure of complex 1, because
of the strong overlapping in case of the atomic thermal
ellipsoids plot structure viewing. In this ball-and-stick model
the hydrogen atoms are omitted for the simplicity of perception.
2.1.2. Complex 1
A crystal sample of cadmium complex 1 suitable for X-ray
structural analysis was obtained by slow evaporation of solution
of ligand (20 mg) and CdI2 (26 mg, 1 eq.) in acetonitrile (5 ml).
Off-white crystals. C44H34Cd3I6N6. Elemental analysis (calcd): C,
30.28; H, 1.96; N, 4.81. Found, %: C 30.21, H 2.07, N 5.01. CCDC
1438668 contains the supplementary crystallographic data for this
complex.
2.2. Synthesis of 10-(pyridin-2-yl)-12,13-dihydro-11H-dibenzo[f,
h]cyclopenta[c]quinoline 5 (monoazatriphenylene) 5
A mixture of triazatriphenylene [14] (0.4 g, 1.3 mmol) and the
1-morpholinocyclopentene (1.04 ml, 6.49 mmol) was stirred under
an argon atmosphere at 200 °C for 2 h. An additional portion of the
1-morpholinocyclopentene (0.52 ml, 3.25 mmol) was added, and
the mixture was stirred at 200 °C for a further 1 h. The reaction
mixture was cooled to room temperature, acetonitrile (30 ml)
was added, and stirring continued for 3 h. The precipitate formed
was filtered off, washed with acetonitrile, and dried. Yield 0.35 g
(1.01 mmol, 78%). C25H18N2. M.p. 181–183 °C. NMR 1H (CDCl3, d,
ppm): 2.25 (2H, m, CH2), 3.63 (2H, t, 3J = 7.2 Hz, CH2), 3.73 (2H, t,
3J = 7.2 Hz, CH2), 7.33 (1H, m, H-50(Py)), 7.62–7.74 (4H, m, CHarom.),
7.92 (1H, ddd, 3J = 7.5 Hz, J = 1.8 Hz, H-40(Py)), 8.60 (1H, m, H-30
4
(Py)), 8.63–8.77 (4H, m, H-6’(Py)+ CHarom.), 9.51 (1H, m, H-8).
NMR 13C (CDCl3, d, ppm): 26.1, 33.2, 37.4, 122.4, 122.9, 123.1,
123.3, 123.7, 126.1, 126.6, 127.2, 127.3, 127.7, 128.3, 130.1,
130.8, 131.1, 131.8, 136.4, 138.9, 144.9, 148.5, 150.3, 151.9,
158.9. ESI-MS, m/z: found 347.15, calculated 347.15 (M+H)+.