Synthesis of novel linear exo-bidentate bispyridine ligands and their complexes with silver(I) tetrafluoroborate

Article abstract of DOI:10.1023/A:1021337526344

Novel exo-bidentate ligands containing two γ-pyridyl fragments and their complexes with silver(I) tetrafluoroborate were synthesized.

Full text of DOI:10.1023/A:1021337526344

Russian Chemical Bulletin, International Edition, Vol. 51, No. 10, pp. 1957—1958, October, 2002
1957
Synthesis of novel linear exoꢀbidentate bispyridine ligands
and their complexes with silver(I) tetrafluoroborate
ꢀ
S. Z. Vatsadze, V. N. Nuriev, A. V. Chernikov, and N. V. Zyk
Department of Chemistry, M. V. Lomonosov Moscow State University,
Leninskie Gory, 119992 Moscow, Russian Federation.
Fax: +7 (095) 939 0290. Eꢀmail: nvn@org.chem.msu.ru
Novel exoꢀbidentate ligands containing two γꢀpyridyl fragments and their complexes with
silver(I) tetrafluoroborate were synthesized.
Key words: supramolecular chemistry, pyridine, 4ꢀsubstituted anilines, 1,4ꢀphenylenediꢀ
amine, crossꢀcoupling, silver tetrafluoroborate, organic ligands.
Scheme 1
The supramolecular chemistry of polymeric systems
based on organic ligands and nontransition metal salts is
under intense development. Ligands containing two
γꢀpyridyl residues linked to the ethylidene or arylidene
fragment become the most important building blocks for
supramolecular systems.1 Such exoꢀbidentate pyridine
ligands as transꢀ1,2ꢀbis(4ꢀpyridyl)ethylene2 (stilbazole)
and 1,4ꢀbis(4ꢀpyridyl)ꢀ2,3ꢀdiazaꢀ1,3ꢀbutadiene3 react
with silver(I) tetrafluoroborate and nickel(II) nitrate to
form polymeric compounds (MLXn)m and (ML2Xn)m, reꢀ
spectively, where M is the complexꢀforming metal, L is
the organic ligand, and X is the anion. At the same time,
complex compounds containing exoꢀdipyridyl ligands with
the arylenediethylene bridging group remain virtually unꢀ
studied.4
We synthesized 1,4ꢀbis[2ꢀ(4ꢀpyridyl)ethenyl]benzene
(1) and its azomethine analogs 2 and 3 (Scheme 1). Comꢀ
pound 1 was prepared using a standard procedure. Comꢀ
pounds 2 and 3 were synthesized for the first time. Comꢀ
pound 2 was synthesized by the condensation of pꢀpheꢀ
nylenediamine with two equivalents of pyridineꢀ4ꢀcarbꢀ
aldehyde in toluene. Compound 3 was synthesized by the
condensation of 4ꢀbromaniline with pyrididineꢀ4ꢀcarbꢀ
aldehyde followed by crossꢀcoupling of imine 4 that
formed with 4ꢀvinylpyridine in the presence of bis(triꢀ
phenylphosphine)palladium dichloride. The structures of
these compounds were confirmed by the 1H and 13С NMR
spectroscopic and elemental analysis data.
Compounds 1, 2, and 3 were used as ligands in the
reaction with silver(I) tetrafluoroborate to afford comꢀ
plexes 5—7, whose composition corresponds to the
AgBF4•L formula according to the elemental analysis
data. The IR spectra of complexes 5—7 exhibit an absorpꢀ
tion band at 1050 cm–1 corresponding to the tetrafluoroꢀ
borate anion. The powder Xꢀray diffraction analysis of the
complexes indicated that all of them were crystalline with
Reagents and conditions: i. 4ꢀvinylpyridine, Et3N,
[Pd(PPh3)2]Cl2, 100 °С; ii. pꢀphenylenediamine, piperidine,
toluene, boiling; iii. 4ꢀbromaniline, piperidine, toluene, boiling;
iv. 4ꢀvinylpyridine, Et3N, [Pd(PPh3)2]Cl2.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1804—1805, October, 2002.
1066ꢀ5285/02/5110ꢀ1957 $27.00 © 2002 Plenum Publishing Corporation

1958
Russ.Chem.Bull., Int.Ed., Vol. 51, No. 10, October, 2002
Vatsadze et al.
—CH=N—); 8.75 (d, 2 H, Py(2), Py(6), J = 6.0 Hz). 13C NMR,
δ: 120.5, 122.2, 122.6, 132.3, 142.4, 149.7, 150.6, 158.2.
Synthesis of complexes 5—7 (general procedure). The comꢀ
plexes were synthesized according to a described procedure2
using a slow diffusion of solutions of the ligand (2 equiv.) in
anhydrous methylene chloride and silver(I) tetrafluoroborate
(1 equiv.) in dry acetonitrile. The finely crystalline precipitate
that formed was filtered off, thoroughly washed with a fivefold
excess of methylene chloride and acetonitrile to remove possible
admixtures of the initial reactants, and dried in vacuo with weak
heating.
similar main reflection sets. This suggests that the comꢀ
pounds possess similar unit cell systems.
Thus, the novel exoꢀbidentate ligands containing two
γꢀpyridyl fragments and their complexes with AgBF4 were
synthesized.
Experimental
1
H and 13C NMR spectra (δ, ppm, J/Hz) were recorded on
a Varian VXRꢀ400 instrument with working frequencies of 400
and 100 MHz, respectively, at 28 °С in CDCl3. IR spectra
(ν/cm–1) were recorded on a URꢀ20 instrument in Nujol. Xꢀray
diffraction analysis was carried out on a Dronꢀ3M diffractometer
(λ(Cu—Kα) = 1.5418 Å, θ/2θ scan mode: 5.5—65 with the
0.05 increment), and dn reflections were presented (1000•I/Imax).
Melting points of substances were determined in an open capilꢀ
lary and were uncorrected. All reagents were commercial
(Acros®, Lancaster®) and used without additional purification.
1,4ꢀBis[(E )ꢀ2ꢀ(4ꢀpyridyl)ethenyl]benzene (1) was syntheꢀ
sized using a described procedure5 in 62% yield with m.p. 250 °С.
1H NMR, δ: 7.05 (d, 2 Н, CH=CH—Ar, J = 16.3 Hz); 7.29 (d,
2 H, Py—CH=CH, J = 16.3 Hz); 7.37 (d, 4 H, Py(3), Py(5), J =
6.2 Hz); 7.55 (s, 4 H, Ar(2), Ar(3), Ar(5), Ar(6)); 8.58 (d, 4 H,
Py(2), Py(6), J = 6.2 Hz). 13C NMR, δ: 120.9, 127.1, 128.8,
129.3, 130.4, 135.3, 144.3, 150.3. IR, cm–1: 1620—1600 (br,
С=С, C=N).
Condensation of anilines with 4ꢀpyridinecarbaldehyde (genꢀ
eral procedure). A mixture of aldehyde (20 mmol) and aniline
(20 mmol) in toluene (50 mL) containing piperidine (0.1 mL)
was boiled for 2 h with a Dean—Stark trap. The solvent was
evaporated, and the residue was recrystallized from 2ꢀpropanol
or ethanol.
N,N´ꢀBis[(E )ꢀ4ꢀpyridylmethylidene]ꢀ1,4ꢀphenylenediamine
(2). The yield was 92%, m.p. 165 °С (from 2ꢀpropanol).
1H NMR, δ: 7.04 (d, 4 H, Py(3), Py(5), J = 5.5 Hz); 8.02 (s,
4 H, Ar(2), Ar(3), Ar(5), Ar(6)); 8.44 (s, 2 H, —CH=N—); 8.56
(d, 4 H, Py(2), Py(6), J = 5.5 Hz). 13C NMR, δ: 121.8, 123.7,
134.7, 150.8, 151.2, 156.5. IR, cm–1: 1630 (C=C), 1600 (C=N),
1580 (Py). Found (%): C, 75.26; H, 5.01; N, 19.39. C18H14N4.
Calculated (%): C, 75.51; H, 4.93; N, 19.57.
Complex of 1,4ꢀbis[(E )ꢀ2ꢀ(4ꢀpyridyl)ethenyl]benzene with
AgBF4 (5). The reaction of compound 1 (0.568 g, 2 mmol)
with AgBF4 (0.192 g, 1 mmol) afforded a yellow powder
(150 mg, 32%) with m.p. 353 °С (decomp.). IR, cm–1: 1615 (br,
C=C, C=N), 1050 (br, BF4). Found (%): C, 50.40; H, 3.36;
N, 5.86. C18H14N4•AgBF4. Calculated (%): C, 50.15; H, 3.37;
N, 5.85. Xꢀray diffraction pattern: 9.0416 (563), 4.5387 (1000),
3.3650 (486).
Complex of N,N´ꢀbis[(E )ꢀ4ꢀpyridylmethylidene]ꢀ1,4ꢀpheꢀ
nylenediamine with AgBF4 (6). The reaction of compound 2
(0.568 g, 2 mmol) with AgBF4 (0.192 g, 1 mmol) afforded a
yellow powder (130 mg, 29%) with m.p. 381 °С (decomp.).
IR, cm–1: 1615 (br, C=N); 1050 (br, BF4). Found (%): C, 44.62;
H, 2.78; N, 11.48. C19H15N3•AgBF4. Calculated (%): C, 44.95;
H, 2.93; N, 11.65. Xꢀray diffraction pattern: 9.0484 (475), 4.5064
(1000), 3.3648 (350).
Complex of Nꢀ[(E )ꢀ4ꢀpyridylmethylidene]ꢀ4ꢀ[(E)ꢀ2ꢀ(4ꢀpyriꢀ
dyl)ethenyl]aniline with AgBF4 (7). The reaction of compound 3
(0.568 g, 2 mmol) with AgBF4 (0.192 g, 1 mmol) afforded a dark
yellow powder (130 mg, 29%) with m.p. 376 °С (decomp.).
IR, cm–1: 1615, 1590 (C=С, C=N), 1050 (br, BF4). Found (%):
C, 48.02; H, 3.15; N, 9.21. C18H14N4•AgBF4. Calculated (%):
C, 47.54; H, 3.13; N, 8.75. Xꢀray diffraction pattern: 9.2979
(760), 4.5062 (1000), 3.3837 (686).
The authors thank F. M. Spiridonov (Department of
Chemistry, Moscow State University) for help in Xꢀray
diffraction analysis. This work was financially supported
by the Russian Foundation for Basic Research (Project
No. 99ꢀ03ꢀ33094).
Nꢀ[(E )ꢀ4ꢀPyridylmethylidene]ꢀ4ꢀ[(E)ꢀ2ꢀ(4ꢀpyridyl)etheꢀ
nyl]aniline (3) was synthesized similarly to compound 1 in 70%
yield with m.p. 193 °С. 1H NMR (protons of the 4ꢀpyridylꢀ
carbimine fragment are marked by stroke), δ: 7.00 (d, 1 H,
ArꢀСH=CH, J = 16.4 Hz); 7.26 (d, 2 H, Ar(2), Ar(6), J =
7.2 Hz); 7.29 (d, 1 H, СH=CH—Py, J = 16.4 Hz); 7.36 (d, 2 H,
Ar(3), Ar(5), J = 7.2 Hz); 7.57 (d, 2 H, Py(3), Py(5), J =
6.0 Hz), 7.74 (d, 2 H, Py(3´), Py(5´), J = 6.0 Hz); 8.46 (s, 1 H,
—CH=N—); 8.57 (d, 2 H, Py(2), Py(6), J = 6.0 Hz); 8.67 (d,
2 H, Py(2´), Py(6´), J = 6.0 Hz). 13C NMR, δ: 120.7, 121.5,
122.2, 126.0, 131.8, 132.5, 135.6, 142.5, 144.4, 150.1, 150.5,
150.9, 157.8. IR, cm–1: 1615 (C=C), 1590 (C=N). Found (%):
C, 78.31; H, 5.53; N, 12.52. C19H15N3. Calculated (%): C, 79.98;
H, 5.30; N, 14.73.
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Nꢀ[(E )ꢀ4ꢀPyridylmethylidene]ꢀ4ꢀbromaniline (4). The yield
1
was 81%, m.p. 74 °С (cf. Ref. 6: m.p. 81 °С). H NMR, δ: 7.10
(d, 2 H, Ar(3), Ar(5), J = 8.5 Hz); 7.51 (d, 2 H, Ar(2), Ar(6), J =
8.5 Hz); 7.71 (d, 2 H, Py(3), Py(5), J = 6.0 Hz); 8.40 (s, 1 H,
Received March 15, 2002;
in revised form July 1, 2002