Preparation and spectral properties of β-bromo-substituted Mn(III) tetraphenylporphyrinates

Article abstract of DOI:10.1134/S1070363215050217

Interaction of 5,10,15,20-tetraphenylporphyrin, 2-bromo-5,10,15,20-tetraphenylporphyrin, and 2,3,12,13-tetrabromo-5,10,15,20-tetraphenylporphyrin with manganese(II) chloride in dimethylformamide has been studied by means of spectrophotometry. The corresponding chloride acido complexes of manganese(III) has been so prepared and identified. The complexes could be reduced into manganese(II) tetraphenylporphyrinates in the presence of potassium hydroxide in dimethylformamide.

Full text of DOI:10.1134/S1070363215050217

ISSN 1070-3632, Russian Journal of General Chemistry, 2015, Vol. 85, No. 5, pp. 1132–1135. © Pleiades Publishing, Ltd., 2015.
Original Russian Text © N.V. Chizhova, S.V. Zvezdina, Yu.S. Kataleva, N.Zh. Mamardashvili, 2015, published in Zhurnal Obshchei Khimii, 2015, Vol. 85,
No. 5, pp. 838–841.
Preparation and Spectral Properties of β-Bromo-Substituted
Mn(III) Tetraphenylporphyrinates
N. V. Chizhovaa, S. V. Zvezdinaa, Yu. S. Katalevab, and N. Zh. Mamardashvilia
a Krestov Institute of Solutions Chemistry, Russian Academy of Sciences,
ul. Akademicheskaya 1, Ivanovo, 153040 Russia
e-mail: nvc@isc-ras.ru
b Ivanovo State Chemical-Technological University, Ivanovo, Russia
Received January 13, 2015
Abstract—Interaction of 5,10,15,20-tetraphenylporphyrin, 2-bromo-5,10,15,20-tetraphenylporphyrin, and
2,3,12,13-tetrabromo-5,10,15,20-tetraphenylporphyrin with manganese(II) chloride in dimethylformamide has
been studied by means of spectrophotometry. The corresponding chloride acido complexes of manganese(III)
has been so prepared and identified. The complexes could be reduced into manganese(II) tetraphenyl-
porphyrinates in the presence of potassium hydroxide in dimethylformamide.
Keywords: β-bromo-substituted tetraphenylporphyrin, complex formation, metal exchange, tetraphenylpor-
phyrinate, manganese, spectral properties
DOI: 10.1134/S1070363215050217
Metal-containing porphyrins are important natural
compounds, being components of chloroplasts, hemo-
globins, myoglobin, cytochromes, and other biomole-
cules [1]. Porphyrine complexes with manganese are
known for the low redox potential of the central ion E
(Mn2+/Mn3+) and therefore act as efficient biocatalysts.
Recently, manganese porphyrinates possessing pro-
perties of molecular magnetic and capable of forming
nanoporous structures have been prepared; these
compounds can be used for development of novel
materials. Manganese complexes with tetraphenyl-
porphyrin have been described earlier [2–4].
In order to prepare manganese complexes with β-
bromo-substituted tetraphenylporphyrins and elucida-
tion of bromine effect on coordination properties of
porphyrins, in this work we studied coordination of
5,10,15,20-tetraphenylporphyrin (I), 2-bromo-5,10,15,20-
tetraphenylporphyrin (II), and 2,3,12,13-tetrabromo-
5,10,15,20-tetraphenylporphyrin (III) with MnCl2 in
Scheme 1.
R4
R4
R3
R1
R3
R1
R2
R4
R3
R2
R4
R3
R3
R4
R2
R3
R4
R2
NH
N
N
N
N
N
N
M
HN
R3
R3
R2
R2
R4
I−III
R4
IV−VI
R1 = R2 = R3 = H (I, IV); R1 = Br, R2 = R3 = H (II, V); R1 = R2= Br, R3 = H (III, VI); R4 = C6H5, M = (Cl)Mn(III).
1132

PREPARATION AND SPECTRAL PROPERTIES OF β-BROMO-SUBSTITUTED
Table 1. Electronic absorption spectra of porphyrines I–III in CH2Cl2 [λ, nm (log ε)]
1133
Comp. no.
Band I
Band II
Bands III, IV, and V
Soret band
Reference
I
II
647 (3.89)
648 (3.67)
648 (3.79)
685 (4.02)
683 (4.06)
591 (3.96)
593 (3.70)
593 (3.81)
612 (3.58)
612 (3.70)
549 (4.08), 514 (4.40)
552 (3.72), 517 (4.27)
551 (3.78), 518 (4.33)
533 (4.30)
417 (5.61)
421 (5.55)
421 (5.58)
436 (5.52)
436 (5.46)
This work
[7]
This work
[8]
III
533 (4.31)
This work
Table 2. Electronic absorption spectra of manganese porphyrinates
Complex
Solvent
λ, nm (logε)
Reference
[2]
I–Mn(II)
I–Mn(II)
II–Mn(II)
III–Mn(II)
IV
DMSO
607, 569, 530, 437
615, 575, 533, 440
620, 580, 536, 445
635. 590, 455
DMF + KОНs
DMF + KОНs
DMF + KОНs
CHCl3
616 (3.03), 582 (4.00), 524 (3.81), 478 (4.98), 402 (4.64)
536, 416
630 sh, 534 (4.54), 418 (5.50)
[2]
[3]
[4]
I–(N3)2Mn(IV)а CH2Cl2
I–(N)Mn(V)а
CHCl3
IV
СНCl3
615 (3.90), 581 (3.99), 526 (3.89),
478 (4.90), 402 (4.56), 375 (4.62)
619 (3.89), 584 (3.96), 528 (3.84), 480 (4.78), 405 (4.55), 380
(4.60)
V
СНCl3
VI
CHCl3
642 (4.04), 600 (4.07), 493 (4.88), 380 (4.77)
a N3 azide ion; N nitride ion.
boiling dimethylformamide by means of spectrophoto-
metry (Scheme 1).
with H2P, porphyrin; MX2(Solv)n–2, the solvated metal
salt; Solv, solvent; MP, metalloporphyrin.
Since the electronic absorption and 1H NMR
spectra of the starting porphyrins and the manganese
complexes were significantly different (Tables 1 and 2;
figure), those methods could be used to study the
complexes formation.
The electronic absorption spectrum of the reaction
mixture in chloroform contained the bands with maxi-
mums at λmax = 617, 582, 524, 477, 402, and 375 nm,
the bands of the starting compound I with maximums
at 647, 591, 549, 514, and 417 nm being vanished.
The complex formation of porphyrins with MnX2
(X = Cl– or CH3COO–) is generally accompanied with
instantaneous oxidation of Mn(II) of the porphyrinates
into Mn(III) to give the Mn(III)(Х)P compounds (Р
being the porphyrine dianion and Х being the acido
ligand) [5]. The reaction could not be stopped at the
stage of formation of Mn(II) porphyrinates, the
exceptions being tetraphenylporphyrins with a few
electron-accepting substituents in the macrocycle and
phenyl groups [6].
When a single bromide atom was introduced at β-
position of tetraphenylporphyrin (the +С effect thus
came into play), the corresponding (Cl)Mn(III) 2-
bromo-5,10,15,20-tetraphenylporphyrinate (V) complex
was formed 1.2 times faster as compared to the
complex IV. The electron-donating substituents
increased the electron density at tertiary nitrogen
atoms of the macrocycle and thus enhanced the
coordination interaction between the cation solvate
complex [MX2(Solv)n–2] and the porphyrin in the
transition state [9]. However, (Cl)Mn(III) 2,3,12,13-
tetrabromo-5,10,15,20-tetraphenylporphyrinate (VI)
complex was formed within 2.5 h in boiling DMF,
likely due to sterically restricted coordination of
MnCl2 with the tetrabromo derivative III.
The experiments revealed that the complex
formation of porphyrin I with MnCl2 (1 : 20 mol/mol)
in the boiling DMF occurred within 80 min to yield
(Cl)Mn(III) 5,10,15,20-tetraphenylporphyrinate (IV):
H2P + MX2(Solv)n–2 ↔ (Solv)mMP + 2НX + (n – 2 – m)Solv,
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 85 No. 5 2015

1134
CHIZHOVA et al.
The prepared compounds, similarly to (Cl)Mn(III)
A
octaphenyltetraazaporphyrinate [12], could be reduced
into the corresponding Mn(II) porphyrinates upon
shaking of the sealed solution in DMF with KOH
during 5–10 min at 20°С. Chromatographic separation
of compounds IV–VI at (alumina, Merck; eluting with
chloroform) was accompanied with their partial
reduction as well.
EXPERIMENTAL
Electronic absorption spectra were recorded using a
Cary-50 spectrophotometer at room temperature. TLC
analysis was performed on Silufol plates eluting with
chloroform. 1Н NMR spectra of the solutions in CDCl3
were recorded using a Bruker AV III-500 instrument.
Elemental analysis was performed using a Flash EA
1112 analyzer.
λ, nm
Electronic absorption spectra of porphyrine III (1) and
complex VI (2) in chloroform.
In the presence of cadmium(II) chloride (Н2Р : CdCl2 =
1 : 10 mol/mol), the manganese complexes were
formed faster (within 20 min, the unsubstituted
complex IV; within 25 min, the monobrominated
complex V; and within 45 min, the tetrabrominated
complex VI), following the scheme below:
DMF, СНCl3, hexene, tetraphenylporphyrin I
(Aldrich), and CdCl2 (“chemical pure” grade) were
used as received; MnCl2 (“chemical pure” grade) was
annealed at 200°С в during 4 h.
2-Bromo-5,10,15,20-tetraphenylporphyrin (II)
was prepared via the procedures adopted from [7, 8].
1Н NMR spectrum, δ, ppm: 8.92–8.89 m (2Н), 8.86 s
(1Н), 8.85–8.82 m (2Н), 8.79–8.77 m (2Н), 8.22 m
(6Н), 8.11 m (2Н), 7.81–7.73 m (12Н), –2.82 s (2Н).
H2P + CdX2(Solv)n–2 ↔ (Solv)mCdP + 2НX + (n – 2– m)Solv,
CdP + MX2(Solv)n–2 → CdХ2(Solv)n–2 + MP.
The accelerated complexes formation was due to
the absence of the N–H bonds cleavage in the course
of the metal exchange reaction involving labile cad-
mium complex. The observed decrease of Cd(II) tetra-
phenylporphyrinate reactivity upon introduction of
bromine atom at the pyrrole rings was due to the
strengthened N→Cd σ-bond [10].
2,3,12,13-Tetrabromo-5,10,15,20-tetraphenyl-
porphyrin (III) was prepared via the procedures
adopted from [7, 8]. 1Н NMR spectrum, δ, ppm: 8.72 s
(4Н), 8.21 d (8Н), 7.83 n (12Н), –2.80 s (2Н).
Complex formation of the porphyrins I–III with
MnCl2 was monitored by means of spectrophotometry
(the mixture was periodically sampled; the specimen
was dissolved in chloroform and analyzed) and TLC.
The complexes IV–VI were characterized by
means of elemental analysis as well as electronic
1
absorption and Н spectroscopy. A special feature of
the (Х)Mn(III)P structure the strong accepting
interaction of the metal atom with the porphyrin ligand
due to the direct (N→Mn) p(π)–d(π) interaction
collinear with the σ-bond. Introduction of the acido
ligand at the inner coordination sphere of Mn(III) tetra-
phenylporphyrinate changed the molecule geometry
leading to the appearance of the additional band at λmax
478 nm) and significant red shift of the other bands as
compared to the Mn(II) complex (Table 2). Mn(III)
5,10,15,20-Tetraphenylporphyrinatochlorido-
manganese(III) (IV). a. A mixture of 0.02 g (0.0325 mol)
of compound I in 40 mL of DMF and 0.082 g
(0.650 mol) of MnCl2 was boiled during 80 min. The
mixture was cooled down to ambient, diluted with
water, and solid NaCl was added. The precipitate was
filtered off, washed with water, and dried. Yield
0.0175 g (0.0249 mmol, 77%), Rf 0.76.
tetraphenylporphyrinates
were
paramagnetic;
b. A mixture of 0.02 g (0.0325 mmol) of compound
I and 0.06 g (0.325 mmol) of CdCl2 in 40 mL of DMF
was heated to boiling, and then 0.082 g (0.650 mmol)
of MnCl2 was added. The mixture was boiled during
20 min and then treated as described in procedure a.
1
therefore, the H NMR signals of phenyl groups of
complexes IV–VI were broadened and exhibited a
downfield shift as compared with the diamagnetic
nitride Mn(V) complexes [11].
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 85 No. 5 2015

PREPARATION AND SPECTRAL PROPERTIES OF β-BROMO-SUBSTITUTED
1135
1
Yield 0.018 g (0.0256 mmol, 80%), Rf 0.76. Н NMR
ACKNOWLEDGMENTS
spectrum, δ, ppm: 8.30 br.s (16Н, Нo,m, С6Н5), 7.75
br.s (4Н, Нp, С6Н5). Found, %: С 74.95; Н 3.94; N
7.88. C44H28ClMnN4. Calculated, %: С 75.16; Н 4.01;
N 7.97.
This work was financially supported by Russian
Scientific Foundation, project no. 14-13-00232.
REFERENCES
(Cl)Mn(III) porphyrinates V and VI were prepared
similarly.
1. Rumyantsev, E.V., Antina, E.V., and Chistyakov, Yu.V.,
Khimicheskie osnovy zhizni (The Chemical Basis of
Life), Moscow: Khimiya, Koloss, 2007.
2. Valentine, J.S. and Quinn, A.E., Inorg. Chem.
Commun., 1976, vol. 15, no. 8, p. 1997.
3. Сamerzind, M.J., Hollander, F.J., and Hill, C.L., Inorg.
Chem., 1983, vol. 22, no. 25, p. 3776.
4. Stuzhin, P.A., Repina, N.V., Klyueva, M.E., and
Fedotova, E.V., Russ. J. Phys. Chem., 2004, vol. 78,
no. 6, p. 864.
2-Bromo-5,10,15,20-tetraphenylporphyrinato-
chloridomanganese(III) (V). a. Prepared from 0.02 g
(0.0288 mmol) of compound II and 0.072 g (0.576 mmol)
of MnCl2; reaction duration 65 min. Yield 0.0176 g
(0.0225 mmol, 78%), Rf 0.78.
b. Prepared from 0.02 g (0.0288 mmol) of com-
pound II, 0.053 g (0.288 mmol) of CdCl2, and 0.072 g
(0.576 mmol) of MnCl2; reaction duration 25 min.
5. Boucher, L.J., Coord. Chem. Rev., 1972, vol. 7, no. 3,
p. 289. DOI: 10.1016/S0010-8545(00)80024-7.
1
Yield 0.018 g (0.0230 mmol, 80%), Rf 0.78. Н NMR
6. Doro, F.G., Lindsay Smith, J.R., Ferreira, A.G., and
Assis, M.D., J. Mol. Catal. (A), 2000, vol. 164, p. 97.
DOI: 10.1016/S1381-1169(00)00352-6.
7. Lembo, A., Tagliatesta, P., and Guldi, D.M., J. Phys.
Chem. (A), 2006, vol. 110, no. 40, p. 11424. DOI:
10.1021/jp062735h.
spectrum, δ, ppm: 8.20 br.s (16Н, Нo,m, С6Н5), 7.55
br.s (4Н, Нp, С6Н5). Found, %: С 67.41; H 3.42; N
10.15. C44H27BrСlMnN4. Calculated, %: C 67.58; H
3.48; N 10.22.
8. Kumar, P.K., Bhyrappa, P., and Varghese, B., Tetra-
hedron Lett., 2003, vol. 44, p. 4849. DOI: 10.1016/
S004039(03)01143-2.
9. Koordinatsionnye soedineniya porfirinov i ftalotsianina
(Coordination Compounds of Porphyrin and Phthalo-
cyanine), Moscow: Nauka, 1978.
2,3,12,13-Tetrabromo-5,10,15,20-tetraphenyl-
porphyrinatochloridomanganese(III) (VI). a.
Prepared from 0.02 g (0.0215 mmol) of compound III
and 0.054 g (0.430 mmol) of MnCl2; reaction duration
2.5 h. Yield 0.0166 g (0.0163 mmol, 76%), Rf 0.82.
10. Zvezdina, S.V., Kulikova, O.M., and Mamardashvili, N.Zh.,
Russ. J. Gen. Chem., 2013, vol. 83, no. 11, p. 2103.
DOI: 10.1134/S107036213110248.
11. Buchler, J.W., Drecher, C., and Lay, K.L., Z. Natur-
forsch. (В), 1982, vol. 37, p. 1155.
12. Zvezdina, S.V. Chizhova, N.V., and Mamardashvili, N.Zh.,
Russ J. Gen. Chem., 2014, vol. 84, no. 7, p. 1389. DOI:
10.1134/S1070363214070251.
b. Prepared from 0.02 g (0.0215 mmol) of comound
III, 0.039 g (0.215 mmol) of CdCl2, and 0.054 g
(0.430 mmol) of MnCl2; reaction duration 45 min.
1
Yield 0.017 g (0.0167 mmol, 79%), Rf 0.72. Н NMR
spectrum, δ, ppm: 8.67 br.s (16Н, Нo,m, С6Н5), 8.05
br.s (4Н, Нp, С6Н5). Found, %: С 51.72; Н 2.34; N 5.41.
C44Н24N4СlBr4Mn. Calculated, %: С 51.88; Н 2.38; N 5.50.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 85 No. 5 2015