Synthesis and Spectral and Coordination Properties of meso-Tetraarylporphyrins

Article abstract of DOI:10.1134/S107042801912011X

5,10,15,20-Tetrakis(3,5-dibromophenyl)porphyrin and 5,10,15,20-tetrakis(3-bromo-4-methoxy-phenyl)porphyrin have been synthesized, and their complexing properties with respect to Pd²⁺ ion in acetonitrile at 308–328 K have been studied by spectrophotometry. The synthesized compounds were characterized by UV-Vis, ¹H NMR, and mass spectra. The effect of substitueras in the meso-phenyl rings of the ligands on their spectral and coordination properties was estimated in comparison to 5,10,15,20-tetraphenylporphyrin.

Full text of DOI:10.1134/S107042801912011X

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2019, Vol. 55, No. 12, pp. 1878–1883. © Pleiades Publishing, Ltd., 2019.
Russian Text © The Author(s), 2019, published in Zhurnal Organicheskoi Khimii, 2019, Vol. 55, No. 12, pp. 1888–1894.
Synthesis and Spectral and Coordination Properties
of meso-Tetraarylporphyrins
Yu. B. Ivanovaa,* A. S. Semeikinb, S. G. Pukhovskayab, and N. Zh. Mamardashvilia
a Krestov Institute of Solution Chemistry, Russian Academy of Sciences, Ivanovo, 153045 Russia
b Ivanovo State University of Chemistry and Technology, Ivanovo, 153460 Russia
*e-mail: jjiv@yandex.ru
Received June 4, 2019; revised October 23, 2019; accepted October 24, 2019
Abstract—5,10,15,20-Tetrakis(3,5-dibromophenyl)porphyrin and 5,10,15,20-tetrakis(3-bromo-4-methoxy-
phenyl)porphyrin have been synthesized, and their complexing properties with respect to Pd2+ ion in acetonitrile
at 308–328 K have been studied by spectrophotometry. The synthesized compounds were characterized by
UV-Vis, 1H NMR, and mass spectra. The effect of substituents in the meso-phenyl rings of the ligands on their
spectral and coordination properties was estimated in comparison to 5,10,15,20-tetraphenylporphyrin.
Keywords: porphyrins, basic properties, metalloporphyrins, coordination properties.
DOI: 10.1134/S107042801912011X
Porphyrins constitute a huge class of natural and
synthetic tetrapyrrole compounds containing
a 16-membered aromatic macrocycle. Porphyrins are
characterized by thermal and photochemical stability,
strong absorption over a wide spectral range, and
selective and reversible complexing ability with respect
to various substrates [1–14]. Strong luminescence,
nonlinear optical, redox, semiconducting, and receptor
properties of porphyrins make it possible to use
them for selective binding and targeted delivery of
biologically active substrates, as well as materials for
high-capacity storage units and electrochromic and
photovoltaic devices [13–15].
electronic spectra and therefore can be used to convert
a primary diagnostic response into an analytical optical
sensor signal. They also exhibit phosphorescence
properties which underlie their use as photosensitizers
and markers for time-resolved luminescence immuno-
assay [17].
In this work we synthesized 5,10,15,20-tetrakis-
(3,5-dibromophenyl)porphyrin [1, H2(3,5-BrPh)P] and
5,10,15,20-tetrakis(3-bromo-4-methoxyphenyl)por-
phyrin [2, H2(3-Br-4-MeOPh)P] and studied their
complexation with palladium(II) ions in acetonitrile
at 308–328 K by spectrophotometry. The effect of
substituents in the meso-phenyl rings on the spectral
and coordination properties of porphyrins 1 and 2 was
examined using 5,10,15,20-tetraphenylporphyrin (3,
H2TPP) as reference.
Metalloporphyrins are capable of forming or-
dered structures in crystal and in solution via extra
coordination of neutral or anionic ligands [16].
Until present, porphyrin complexes with almost all
metals of the Periodic Table have been obtained. The
complexation process can be readily and reliably
monitored by spectrophotometry, which contributes to
rapid development of studies in this field. Coordination
properties of porphyrins with respect to metal salts
strongly depend on the nature of substituents present
in the porphyrin macrocycle, which largely determine
the relation between their coordination and acid–base
properties, since protonation of ligands is a competing
process with respect to coordination.
Porphyrins 1 and 2 were synthesized in 16.5 and
23.5% yield, respectively, by condensation of the
corresponding substituted benzaldehydes with pyrrole
in xylene in the presence of chloroacetic acid on
exposure to air (Scheme 1; see Experimental). The
products were characterized by electronic absorption,
1H NMR, and mass spectra.
It is known that the nature and position of substit-
uents in the macrocycle strongly affect acid–base
properties of porphyrins. As we showed previously
[18], introduction of bromine atoms and methoxy
group into the meso-phenyl rings reduce the basicity
of the tetrapyrrole macrocycle in the series: H2TPP <
Of particular interest are porphyrin complexes
with palladium, which show high absorbance in the
1878

SYNTHESIS AND SPECTRAL AND COORDINATION PROPERTIES
1879
Scheme 1.
R2
Br
R1
R2
R1
Br
Br
CHO
N
N
ClCH2COOH
xylene
+
NH
HN
R1
N
H
R2
R2
R1
Br
R1
R2
Br
1 2
,
1, R1 = H, R2 = Br; 2, R1 = OMe, R2 = H.
H2(3-Br-4-MeOPh)P < H2(3,5-BrPh)P. Due to negative
inductive (–I) and weak mesomeric (+M) effects of
bromine atoms, the basicity of H2(3-Br-4-MeOPh)P is
lower by more than an order of magnitude than the
basicity of H2TPP [19]; in the case of H2(3,5-BrPh)P,
the difference is more than two orders of magnitude.
Geometry optimization of porphyrins 1–3 by the PM3
quantum chemical method (HyperChem, version
7.02) showed that their molecules have almost planar
structure with a slight puckering [18]. The dissociation
constants of protonated porphyrins agree well with the
classical views on the substituent effects [17].
icant differences in the electronic absorption spectra of
the free ligands and their complexes. The complexation
of porphyrins with palladium(II) acetate in a pure
solvent follows Eq. (1):
H2P + [Pd(OAc)2(Solv)n–2
]
→ PdP + 2AcOH + (n – 2)Solv,
where H2P stands for porphyrin 1–3, Solv is a solvent
molecule, and n is the metal coordination number.
In all cases, spectrophotometric monitoring of the
complex formation process showed distinct isosbestic
points, and the reactions were of first order with respect
to porphyrin 1–3, as evidenced by the linear plots of
log(c0H P/cH P) versus time τ (s) (Figs. 1–3). The rates
The kinetics of the complex formation of porphyrins
1–3 with palladium in acetonitrile were studied by
spectrophotometry [18–20], taking into account signif-
2
2
(a)
(b)
A
log c0/c0.8
3
0.8
2.1
2
0.6
0.4
0.2
1.4
0.7
1
0.0
0
500
1000 1500
2000 τ, s
0.0
400
500
600
700 λ, nm
Fig. 1. (a) Variation of the electronic absorption spectrum
and (b) log(c0/c)—τ plot (λ 417 nm) for the complexation of
5,10,15,20-tetrakis(3-bromo-4-methoxyphenyl)porphyrin (1)
with palladium(II) acetate in acetonitrile; c1 = 1.8×10–5 M;
cPd = 4.5×10–3 M; temperature, K: (1) 308, (2) 318, (3) 328.
Fig. 2. (a) Variation of the electronic absorption spectrum
and (b) log(c0/c)—τ plot (λ 417 nm) for the complexation of
5,10,15,20-tetrakis(3,5-dibromophenyl)porphyrin (2) with
palladium(II) acetate in acetonitrile; c2 = 1.90×10–5 M; cPd
4.5×10–3 M; temperature, K: (1) 308, (2) 318, (3) 328.
=
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 55 No. 12 2019

IVANOVA et al.
1880
Fig. 3. (a) Variation of the electronic absorption spectrum
and (b) log(c0/c)—τ plot (λ 413 nm) for the complexation
of 5,10,15,20-tetraphenylporphyrin (3) with palladium(II)
acetate in acetonitrile; c3 = 1.97×10–5 M; cPd = 4.5×10–3 M;
temperature, K: (1) 308, (2) 318, (3) 328.
Fig. 4. Temperature dependence of the rate constant of
complex formation for porphyrin 1.
of formation of palladium complexes were low even
at elevated temperature (308–318 K); therefore, the
rate constant at standard temperature was determined
by extrapolation (an example is shown in Fig. 4.). The
order of reactions with respect to the metal salt was
electronic effects of the substituents and deformation of
the macrocycle. The activity of ligands in such systems
is also determined by the structure of acid–base
complexes formed in solution, whose ionizing ability
depends on the degree of proton transfer from the
acid to the base molecule (solvent). The complexation
rate constant may also depend on the nature of the
central metal ion. Analysis of the data in Table 2 and
our previous data on the formation of zinc complexes
of the same porphyrins [18] shows that the rates of
formation of palladium complexes with unsubstituted
tetraphenylporphyrin 3 and octabromo derivative 2 are
more than 500 times lower than the rates of formation
determined as the slope of the log kef—log cZn(OAc)
2
dependence (an example is shown in Fig. 5). Tables 1
and 2 contain characteristics of the electronic absorp-
tion spectra of porphyrins 1–3 and their palladium
complexes, as well as the kinetic parameters of the
complexation reaction. It is seen that substitution in
the meso-phenyl rings affects the coordination and
acid–base properties of porphyrins, obviously due to
H2(3,5-BrPh)P
H2(3-Br-4-MeOPh)P
H2(3-Br-4-MeOPh)P
H2TPP
H2(3,5-BrPh)P
H2TPP
Fig. 5. Correlation between log kef and log cPd(OAc) for the
2
complexation of paladium(II) acetate with porphyrin 2 in
acetonitrile at 328 K; slope 1.1, correlation coefficient 0.999.
Fig. 6. Correlations between ∆H and ΔS for the complexation
of tetraphenylporphyrins 1–3 with (1) Zn2+ and (2) Pd2+.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 55 No. 12 2019

SYNTHESIS AND SPECTRAL AND COORDINATION PROPERTIES
1881
Table 1. Electronic absorption spectra of tetraphenylporphyrins 1–3 and their palladium complexes in acetonitrile and overall
protonation constants pKb1,2
λ, nm (logε)
Compound
H2TPP
pKb1,2
Soret band
413 (5.02)
λ4
λ3
λ2
λ1
19.8 [19]
(18.61)[18]
512 (3.56)
546 (3.12)
589 (2.92)
646 (2.96)
PdTPP
H2(3,5-BrPh)P
412 (5.14)
417 (5.01)
375 sh (4.43)
416 (4.66)
418 (5.03)
426 (5.12)
508 (4.06)
546 (3.67)
544 (3.76)
649 (4.59)
513 (3.91)
511 (4.05)
588 (3.66)
593 (3.97)
17.50
18.09
Pd(3,5-BrPh)P
654 (3.96)
H2(3-Br-4-MeOPh)P
Pd(3-Br-4-MeOPh)P
515 (3.84)
559 (3.90)
552 (3.70)
–
593 (3.62)
–
651 (3.750
600 (3.75)
of the corresponding zinc complexes; furthermore,
the complexation with palladium is a more energy-
consuming process. In the case of bromomethoxy
derivative 1, the difference in the reaction rates is more
than 800 times.
processing were reported in [23, 24]. The kinetic
measurements were carried out using cells with ground-
joint caps at three temperatures in the range from 308
to 328 K; each experiment was run in triplicate; the
temperature was maintained with an accuracy of
1
±0.1 K. The H NMR spectra were recorded on a
Presumably, the transition state in the examined
reaction is more polar than the initial state. This is
confirmed by the negative entropies of reaction, as
well as by the Ea—ΔS≠ correlations which showed
the kinetic compensation effect due to solvation of the
metal salt and N–H coordination site of porphyrin in the
transition state [20]. Godd correlations between Ea and
ΔS≠ were observed (Fig. 6) for both zinc and palladium
complexes of tetraphenylporphyrins 1–3.
Bruker AV III-500 spectrometer using TMS as internal
standard. The mass spectra were recorded obtained on
a Shimadzu Axima Confidence spectrometer (MALDI-
TOF). 5,10,15,20-Tetraphenylporphyrin (3) was com-
mercial product (Porphychem). Ligands 1 and 2 were
purified by chromatography on alumina of Brockmann
activity grade III using methylene chloride as eluent
[22]. Their purity was checked by TLC on Silufol plates
with a sorbent layer thickness of 0.5 mm (Merck) using
methylene chloride as eluent. Acetonitrile used as
solvent contained less than 0.03% of water.
Thus, the results of our study showed that chemical
modification of the porphyrin macrocycle alters its
acid–base and coordination properties, which may be
useful for controlled change of the reactivity of por-
phyrin ligands for certain purposes.
5,10,15,20-Tetrakis(3,5-dibromophenyl)por-
phyrin (1). A flask equipped with a reflux condenser
and a Dean–Stark trap was charged with a solution
of 5.0 g of chloroacetic acid in 150 mL of xylene
(isomer mixture). The solution was heated to the
boiling point, a solution of 8.7 g (33.0 mmol) of
3,5-dibromobenzaldehyde and 2.3 mL (33.2 mmol)
of pyrrole in 50 mL of xylene was gradually added,
and the mixture was refluxed for 0.5 h and then for
EXPERIMENTAL
Spectrophotometric titration with solutions of
perchloric acid in acetonitrile was performed using
Varian Cary 100 and SPEK SSP-715 spectrophotom-
eters. Details of the experimental procedure and data
Table 2. Kinetic parameters of the complex formation of porphyrins 1–3 with zinc(II) and palladium(II) acetates in acetonitrile
Porphyrin
c
M(OAc) ×103, M
k298×103, L mol–1 s–1
Ea, kJ/mol
ΔS≠, J mol–1 K–1
2
M = Zn
302 ± 1
88 ± 1
91 ± 1
M = Pd
56 ± 1
10 ± 1
17 ± 2
H2TPP [28]
H2(3,5-BrPh)P
H2(3-Br-4-MeOPh)P
1.84
4.5
4.5
70 ± 2
78 ± 2
80 ± 1
–28 ± 2
–11 ± 1
–5 ± 1
H2TPP [20]
H2(3,5-BrPh)P
H2(3-Br-4-MeOPhPh)P
4.5
4.5
4.5
81 ± 2
92 ± 2
88 ± 2
–43 ± 2
–20 ± 2
–29 ± 2
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 55 No. 12 2019

IVANOVA et al.
1882
an additional 1 h while bubbling air. The solvent was
removed by steam distillation, and the precipitate was
filtered off, washed with water, and air-dried at 70°C.
It was dissolved in chloroform, and the product was
filtered off. The product was dissolved in chloroform–
trifluoroacetic acid (100:1 by volume), the solution was
filtered, the filtrate was neutralized with diethylamine
until its originally green color changed to red, and the
precipitate was filtered off, washed with chloroform,
and dried to isolate 1.5 g of 1. The filtrate was com-
bined with the washings and subjected to alumina
chromatography. The eluate was concentrated, and
the product was precipitated with methanol to isolate
an additional 0.2 g of 1. Overall yield 1.7 g (16.5%),
Rf 0.87 (benzene–hexane, 2:1). Electronic absorption
spectrum, λ, nm (log ε): 648 (3.73), 590 (3.91), 550
REFERENCES
1. Bazanov, M.I., etal., Uspekhikhimiiporfirinov(Advances
in Porphyrin Chemistry), St. Petersburg: Nauch.-Issled.
Inst. Khimii Sankt-Peterb. Gos. Univ., 1999, vol. 2.
2. Andrianov, V.G., et al., Uspekhi khimii porfirinov
(Advances in Porphyrin Chemistry), St. Petersburg:
Nauch.-Issled. Inst. Khimii Sankt-Peterb. Gos. Univ.,
2001, vol. 3.
3. Avlasevich, Yu.A., et al., Uspekhi khimii porfirinov
(Advances in Porphyrin Chemistry), St. Petersburg:
VVM, 2004, vol. 4.
4. Antipin, I.S., et al., Uspekhi khimii porfirinov (Advances
in Porphyrin Chemistry), St. Petersburg: Nauch.-Issled.
Inst. Khimii Sankt-Peterb. Gos. Univ., 2007, vol. 5.
5. Sheinin, V.B., Mamardashvili, N.Z., and Ratkova, E.L.,
J. Porphyrins Phthalocyanines, 2008, vol. 12, p. 1211.
https://doi.org/10.1142/S1088424608000595
6. Kruk, M.M., Starukhin, A.S., Mamardashvili, N.Z.,
Mamardashvili, G.M., Ivanova, Y.B., and Maltseva, O.V.,
J. Porphyrins Phthalocyanines, 2009, vol. 13, p. 1148.
https://doi.org/10.1142/S1088424609001492
7. Mamardashvili, N.Zh., Maltseva, O.V., Ivanova, Y.B.,
and Mamardashvili, G.M., Tetrahedron Lett., 2008,
vol. 49, p. 3752.
1
(3.93), 516 (4.33), 421 (5.64). H NMR spectrum
(CDCl3–TFA), δ, ppm: –1.14 s (4H, NH), 8.40 t (4H,
4′-H, J = 1.6 Hz), 8.64 d (8H, 2′-H, 6′-H, J = 1.6 Hz),
8.87 s (8H, β-H). Mass spectrum, m/z (Irel, %): 1167.38
[M – Br + H]+, 1246.64 [M + H]+. C44H22Br8N4.
Calculated: M 1246.96.
5,10,15,20-Tetrakis(3-bromo-4-methoxyphenyl)-
porphyrin (2) was synthesized in a similar way from
7.1 g (33 mmol) of 3-bromo-4-methoxybenzaldehyde.
Yield 2.0 g (23.5%), Rf 0.63 (benzene). Electronic
absorption spectrum (CHCl3), λ, nm (logε): 651 (3.90),
594 (3.90), 555 (4.10), 519 (4.31), 423 (5.69). 1H NMR
spectrum (CDCl3), δ, ppm: –2.84 s (2H, NH), 4.22 s
(12H, OCH3), 7.31 d (4H, 5′-H, J = 8.2 Hz), 8.13 d
(4H, 6-H, J = 8.2 Hz), 8.44 s (4H, 2-H), 8.90 s
https://doi.org/10.1016/j.tetlet.2008.04.029
8. Ivanova, Yu.B., Semeikin, A.S., Glazunov, A.V., and
Mamardashvili, N.Zh., Russ. J. Org. Chem., 2010,
vol. 46, p. 917.
https://doi.org/10.1134/S1070428010060230
9. Kruk, N.N., Starukhin, A.S., Mamardashvili, N.Zh.,
Sheinin, V.B., and Ivanova, Yu.B., RU Patent
no. 2345352, 2007.
10. Dougherty, T.J., Gomer, C.J., Henderson, B.W., Jori, G.,
Kessel, D., Korbelik, M., Moan, J., and Peng, Q.,
J. Natl. Cancer Inst., 1998, vol. 90, p. 889.
1
(8H, β-H). H NMR spectrum (CDCl3–TFA), δ, ppm:
–0.99 s (4H, NH), 4.26 s (12H, OCH3), 7.57 d (4H,
5-H), 8.41 d (4H, 6-H), 8.77 s (4H, 2-H), 8.64 s (8H,
β-H). C48H34Br4N4O4 M 1050.44.
https://doi.org/10.1093/jnci/90.12.889
11. Barth, R.F., Soloway, A.H., Goodman, J.H.,
Gahbauer, R.A., Gupta, N., Blue, T.E., Yang, W., and
Tjarks, W., Neurosurgery, 1999, vol. 44, p. 433.
https://doi.org/10.1097/00006123-199903000-00001
ACKNOWLEDGMENTS
12. Vicente, M.G.H., Curr. Med. Chem.: Anti-Cancer Agents,
2001, vol. 1, 175.
https://doi.org/10.2174/1568011013354769
13. Fukuzumi, S., Org. Biomol. Chem., 2003, vol. 1, p. 609.
https://doi.org/10.1039/B300053B
14. Gust, D., Moore, T.A., and Moore, A.L., Acc. Chem.
Res., 2001, vol. 34, p. 40.
This study was performed using the equipment of the
“Upper Volga Regional Center for Physicochemical Srudies”
joint center at the Krestov Institute of Solution Chemistry,
Russian Academy of Sciences.
FUNDING
https://doi.org/10.1021/ar9801301
15. Konovalova, N.V., Kirienko, E.V., and Luzgina, V.N.,
Vestn. Mosk. Inst. Tonk. Khim. Tekhnol., 2006,
no. 1, p. 38.
This study was financially support by the Russian
Foundation for Basic Research (project no. 19-03-00078A).
16. Mamardashvili, G.M., Uspekhi khimii porphyrinov
(Advances in Porphyrin Chemistry), St. Petersburg:
Nauch.-Issled. Inst. Khimii Sankt-Peterb. Gos. Univ.,
2007, vol. 5, p. 168.
CONFLICT OF INTERESTS
The authors declare the absence of conflict of interests.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 55 No. 12 2019

SYNTHESIS AND SPECTRAL AND COORDINATION PROPERTIES
1883
17. Strachan, J.P., Gentemann, S., Seth, J., Kalsbeck, W.A.,
Lindsey, J.S., Holten, D., and Bocian, D.F., J. Am. Chem.
Soc., 1997, vol. 119, p. 11191.
21. Mironov, A.F., Itogi Nauki Tekh., Sovr. Probl. Laz. Fiz.,
Moscow: VINITI, 1990, vol. 3, p. 5.
22. Karyakin, Yu.V. and Angelov, I.I., Chistye khimicheskie
reaktivy (Pure Chemicals), Moscow: Khimiya. 1974.
https://doi.org/10.1021/ja971678q
18. Ivanova, Yu.B., Pukhovskaya, S.G., Semeikin, A.S.,
and Mamardashvili, N.Zh., Abstracts of Papers,
XIII Mezhdunarodnaya Nauchnaya Konferentsiya
23. Ivanova,
Yu.B.,
Churakhina,
Yu.I.,
and
Mamardashvili, N.Zh., Russ. J. Gen. Chem., 2008,
vol. 78, p. 673.
https://doi.org/10.1134/S1070363208040269
“Poblemy sol’vatatsii
i kompleksoobrazovaniya v
rastvorakh” (XIIIth Int. Scientific Conf. “Solvation and
Complex Formation Problems in Solution”), Suzdal’,
Russia, 2018, p. 129.
24. Ivanova, Yu.B., Sheinin, V.B., and Mamardashvili, N.Zh.,
Russ. J. Gen. Chem., 2007, vol. 77, p. 1458.
https://doi.org/10.1134/S1070363207080270
19. Andrianov, V.G. and Malkova, O.V., Makrogeterotsikly,
2009, vol. 2, p. 130.
20. Berezin, B.D., Coordination Compounds of Porphyrins
and Phthalocyanines, New York: Wiley, 1981.
25. Ivanova, Y.B. and Mamardashvili, N.Zh., J. Fluoresc.,
2017, vol. 27, p. 303.
https://doi.org/10.1007/s10895-016-1958-1
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 55 No. 12 2019