Synthesis and spectral properties of meso-substituted Ni2+ octaalkylporphyrinates

Article abstract of DOI:10.1134/S0036023613050069

Nickel(II) 3,7,13,17-tetramethyl-2,8,12,18-tetrabutylporphyrinate and its 5,15-diaza, -diphenyl, and -di(4-bromophenyl) derivatives have been synthesized by the reaction of nickel(II) chloride with corresponding tetrapyrrole ligands in dimethylformamide.

Full text of DOI:10.1134/S0036023613050069

ISSN 0036ꢀ0236, Russian Journal of Inorganic Chemistry, 2013, Vol. 58, No. 5, pp. 574–576. © Pleiades Publishing, Ltd., 2013.
Original Russian Text © N.V. Chizhova, O.V. Mal’tseva, N.Zh. Mamardashvili, 2013, published in Zhurnal Neorganicheskoi Khimii, 2013, Vol. 58, No. 5, pp. 650–653
.
PHYSICAL METHODS OF INVESTIGATION
Synthesis and Spectral Properties
of mesoꢀSubstituted Ni2+ Octaalkylporphyrinates
N. V. Chizhova, O. V. Mal’tseva, and N. Zh. Mamardashvili
Krestov Institute of Solution Chemistry, Russian Academy of Sciences, ul. Akademicheskaya 1, Ivanovo, 153045 Russia
eꢀmail: nvc@iscꢀras.ru
Received December 27, 2011
Abstract—Nickel(II) 3,7,13,17ꢀtetramethylꢀ2,8,12,18ꢀtetrabutylporphyrinate and its 5,15ꢀdiaza, ꢀdipheꢀ
nyl, and ꢀdi(4ꢀbromophenyl) derivatives have been synthesized by the reaction of nickel(II) chloride with
corresponding tetrapyrrole ligands in dimethylformamide.
DOI: 10.1134/S0036023613050069
Palladium and nickel complexes with porphyrins reactions of nickel(II) chloride with ligands I–IV in
are widely used as molecular thermometers, efficient
sensors, and molecular switches [1, 2].
Previously, palladium porphyrinates have been
synthesized by the complexation reaction of Pd2+ catꢀ
ion with 3,7,13,17ꢀtetramethylꢀ2,8,12,18ꢀtetrabutylporꢀ
phine (I) and its 5,15ꢀdiaza (II), ꢀdiphenyl (III), and ꢀ
di(4ꢀbromopnenyl) (IV) derivatives in dimethylforꢀ
mamide (DMF) [3].
boiling DMF have been studied. A significant differꢀ
ence between the electronic absorption spectra of the
initial porphyrin ligands and the resulting nickel porꢀ
phyrinates (figure) enabled the use of the spectrophoꢀ
tometric method for studying the reactions. Optimal
conditions for the synthesis of nickel 3,7,13,17ꢀtetꢀ
ramethylꢀ2,8,12,18ꢀtetrabutylporphinate (V) and its
5,15ꢀdiaza (VI), ꢀdiphenyl (VII), and ꢀdi(4ꢀbromopheꢀ
nyl) (VIII) derivatives have been found and spectral
The present work has focused on the development
of efficient methods of synthesis of nickel complexes
with octaalkylporphyrins I–IV. The complexation properties of the complexes have been studied.
CH3
CH3
М =Pd, X = CH (I),
X
M
X
M = Pd, X = N (II),
H9C4
H9C4
C4H9
C4H9
M = Pd, Х = СꢀС Н (III),
N
N
N
N
6
5
M = Pd, Х = Сꢀ4ꢀBrС Н (IV),
6
4
M = Ni, Х = СH (
М = Ni, Х = N (VI),
M = Ni, X = CꢀC H (VII),
V),
6
5
M = Ni, X = Cꢀ4ꢀBrC H (VIII).
CH3
6
4
CH3
EXPERIMENTAL
Porphyrin ligands I–IV were synthesized as
room temperature. TLC analysis was carried out on
Silufol (G/UV254) plates, elution with a 1 : 1 hexane–
1
chloroform mixture. The H NMR spectra were
described in [4]. Chemically pure grade DMF and
recorded on a Bruker AV IIIꢀ500 spectrometer in deuꢀ
teriochloroform. The IR spectra were recorded on an
Avatar 360ꢀFTꢀIRꢀESP spectrophotometer as KBr
pellets. Elemental analysis was carried out on a Flash
EA 1112 analyzer.
СНСl3 were used as purchased. Chemically pure grade
nickel(II) chloride was annealed at 200 С for 4 h. The
°
course of the complexation reaction of metal cation
with the porphyrin ligand was monitored by spectroꢀ
photometry and thinꢀlayer chromatography (TLC).
The spectrophotometric study procedure was as folꢀ
lows: at definite time intervals, equal volumes of the rabutylporphyrinate (V). A mixture of 0.05 g (0.085
reaction mixture were sampled and dissolved in a defꢀ mmol) of porphyrin I and 0.11 g (0.85 mmol) of NiCl2
Nickel(II) 3,7,13,17ꢀtetramethylꢀ2,8,12,18ꢀtetꢀ
inite amount of DMF. The resulting solution was in 30 mL of DMF was heated to boiling and heated
placed in a cell. The electronic absorption spectra under reflux for 10 min, then cooled (a water–ice–salt
were recorded on a Caryꢀ100 spectrophotometer at mixture), and poured into water. The deposited preꢀ
574

SYNTHESIS AND SPECTRAL PROPERTIES
575
cipitate was filtered off, washed with water, and chroꢀ
matographed on alumina (elution with a 1 : 1 hexane–
A
1.5
chloroform mixture) The yield of complex
V was
0.025 g (0.038 mmol, 45%). Rf = 0.74.
For NiC40N4H52 anal. calcd. (%): C, 74.19; N,
8.66; H, 8.09.
2
1.0
0.5
1
Found (%): C, 74.12; N, 8.62; H, 8.04.
1H NMR (
, ppm, СDCl3): 9.79 (s, 4H, msꢀH),
δ
2.90 (s, 12H, CН3), 2.98 (t, 8Н, CH2CH2CH2CH3),
1.60 (quint, 8Н, CH2CH2CH2CH3), 1.28 (sext, 8Н,
CH2CH2CH2CH3), 0.90 (t, 12H, CH2CH2CH2CH3).
IR (cm–1): 3057 w, 2924 w, 2852 w, 1807 w, 1634 m,
1591 m, 1565 m, 1459 m, 1429 m, 1350 s, 1315 w,
1231 w, 1207 w, 1159 w, 1126 w, 1070 m, 1036 m, 1004 s,
866 w, 833 w, 797 s, 752 s, 710 m, 648 w, 486 w, 460 w.
500
550
600
650
, nm
λ
Electronic absorption spectrum of (
(2) Ni porphyrinate V in chloroform.
1
) porphyrin
I
and
2+
Porphyrinates VI, VII, and VIII were synthesized
and isolated analogously.
to boiling and heated under reflux for 3 min. The yield
was 0.04 g (0.042 mmol, 75%). Rf = 0.78.
For NiC52N4H58Br2 anal. calcd. (%): C, 65.22; N,
5.85; H, 6.10.
Nickel(II) 3,7,13,17ꢀtetramethylꢀ2,8,12,18ꢀtetꢀ
rabutylꢀ5,15ꢀdiazaporphyrinate (VI). A mixture of
0.05 g of porphyrin II and 0.11 g of NiCl2 (1 : 10 molar
ratio) in 60 mL of DMF was heated to boiling and
heated under reflux for 1 min. The yield was 0.024 g
(0.037 mmol, 44%). Rf = 0.75.
Found (%): C, 65.16; N, 5.78; H, 6.05.
1H NMR (
, ppm, CDCl3): 10.10 (s, 2H, msꢀH),
δ
For NiC38N6H50 anal. calcd. (%): C, 70.26; N,
12.94; H, 7.76.
7.84 (d, 4H, Arylꢀortho), 7.75 (d, 4H, Arylꢀmeta), 2.96
(s, 12H, CH3), 2.88 (t, 8H, CH2CH2CH2CH3), 1.27
(quint, 8H, CH2CH2CH2CH3), 1.09 (sext, 8H,
CH2CH2CH2CH3), 0.86 (t, 12H, CH2CH2CH2CH3).
IR (cm–1): 2923 m, 2853 w, 1634 m, 1604 m, 1570
m, 1485 m, 1409 s, 1351 s, 1287 w, 1244 m, 1210 w, 1180
m, 1140 w, 1067 s, 1009 m, 941 m, 927 w, 880 w, 821 m,
808 m, 795 m, 714 m, 695 m, 569 w, 532 w, 482 w.
Found (%): C, 70.20; N, 12.89; H, 7.71.
1H NMR (
, ppm, СDCl3): 9.79 (s, 4H, msꢀH),
δ
3.54 (s, 12H, CH3), 3.96 (t, 8H, CH2CH2CH2CH3),
1.84 (quint, 8Н, CH2CH2CH2CH3), 1.75 (sext, 8Н,
CH2CH2CH2CH3), 0.92 (t, 12H, CH2CH2CH2CH3).
IR (cm–1: 3032 w, 2999 w, 2927 w, 2833 w, 1607 s,
1574 w, 1549 w, 1507 s, 1463 m, 1438 m, 1409 w, 1353 s,
1288 m, 1248 s, 1175 s, 1106 w, 1075 w, 1027 m, 1003 s,
849 w, 802 m, 786 w, 714 w, 639 w, 608 w, 540 w.
Nickel(II) 3,7,13,17ꢀtetramethylꢀ2,8,12,18ꢀtetꢀ
rabutylꢀ5,15ꢀdiphenylporphyrinate (VII). A mixture of
0.05 g of porphyrin III and 0.087 g of NiCl2 (1 :
10 molar ratio) in 50 mL of DMF was heated to boilꢀ
ing and heated under reflux for 1 min. The yield was
0.044 g (0.055 mmol, 82%). Rf = 0.78.
RESULTS AND DISCUSSION
As is known [5], formation of metal porphyrins in
solution is a result of the bimolecular collision of a
porphyrin ligand and a solvated salt (M(Solv)4Cl2).
The complexation reaction rate depends on the coorꢀ
dination interaction of the metal cation with the porꢀ
phyrin nitrogen atoms and the strength of the N–
H bonds of the porphyrin reaction site. The effect of
these factors can vary depending on the porphyrin and
solvent nature. In the interaction of porphyrin ligands
For NiC52N4H60 anal. calcd. (%): C, 78.09; N,
7.01; H, 7.56.
Found (%): C, 78.02; N, 6.96; H, 7.53.
I, III, and IV with NiCl2 in DMF, the transition state
1H NMR (
, ppm, СDCl3): 10.17 (s, 2H, msꢀH),
δ
energy is dominated by the coordination interaction of
the metal cation with the porphyrin nitrogen atoms.
Electronꢀdonor aryl substituents in the 5,15ꢀpositions
of the porphyrin macrocyclic ring enhance the coordiꢀ
nation interaction of the solvate complex cation with
porphyrin in the transition state. As a result, the forꢀ
mation of Ni2+ porphyrinate VII is about one order of
magnitude faster than that of mesoꢀunsubstituted Ni2+
8.04 (d, 4H, Arylꢀortho), 7.93 (t, 4H, Arylꢀmeta), 7.69
(t, Arylꢀpara), 2.98 (s, 12H, CH3), 2.90 (t, 8H,
CH2CH2CH2CH3)
,
1.16
(quint,
8H,
CH2CH2CH2CH3), 1.12 (sext, 8Н, CH2CH2CH2CH3),
0.89 (t, 12H, CH2CH2CH2CH3).
IR (cm–1): 3230 w, 3068 w, 2959 s, 2918 s, 2868 m,
2849 m, 1738 w, 1667 w, 1569 w, 1537 w, 1453 m,
1393 m, 1311 w, 1263 m, 1232 m, 1147 m, 1108 m,
1058 m, 1024 m, 988 m, 934 w, 831 m, 756 w, 729 m,
709 m, 612 w, 515 w, 424 w.
porphyrinate
V. The formation of nickel porphyriꢀ
nates is about 10 times slower than that of palladium
porphyrinates [3]. A similar trend was observed in the
Nickel(II) 3,7,13,17ꢀtetramethylꢀ2,8,12,18ꢀtetꢀ complexation reaction of NiCl2 and PdCl2 with tetraꢀ
rabutylꢀ5,15ꢀbis(4ꢀbromophenyl)porphyrinate (VIII). benzoporphine in DMF [6]. Under comparable conꢀ
A mixture of 0.05 g of porphyrin IV and 0.072 g of ditions, Ni2+ tetrabenzoporphyrinate forms ~5 times
NiCl2 (1 : 10 molar ratio) in 60 mL of DMF was heated as slow as Pd2+ tetrabenzoporphyrinate [6]. This can
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 58 No. 5 2013

576
CHIZHOVA et al.
Electronic absorption spectra of Ni(II) and Pd(II) porphyꢀ
rinates in chloroform
the appearance of band I at 553 nm (table). The
change in the geometry of the porphyrin molecule
upon complexation with Ni2+ ions is clearly maniꢀ
fested in IR spectra: the number of bands decreases
because of the degeneracy of odd inꢀplane vibrations.
Band I
, nm (log
Band II
, nm (log
Soret band
, nm (log )
Compound
λ
ε
)
λ
ε
)
λ
ε
Ni2+
Ni2+
Ni2+
Ni2+
Pd2+
Pd2+
Pd2+
Pd2+
–
–
–
–
I (V)
558 (3.79) 527 (4.11)
552 (4.38) 517 (4.06)
525 (4.10)
412 (5.21)
392 (5.19)
418 (5.10)
414 (5.41)
415 (5.43)
393 (5.40)
420 (5.40)
415 (5.53)
As compared with octaalkylporphyrin
I [11], in the IR
spectra of Ni2+ porphyrinates
V–VIII, the bands of
II
(
VI
VII
VIII
)
N–H stretching and bending vibrations at 3320 and
965 and 685 cm–1 disappear, and strong “metalꢀsensiꢀ
tive” bands at 1004–1024 cm–1 appear. In the
1H NMR spectra, the substitution of nitrogen atoms
III
IV
(
)
(
)
553 (3.60) 528 (4.31)
555 (3.85) 523 (4.35)
546 (4.69) 513 (4.30)
525 (4.25)
–
I
for two mesoꢀcarbon atoms (compounds
V and VI)
–
–
–
II
III
IV
leads to a downfield displacement of the signals of
methyl and butyl groups. The aryl and bromoaryl subꢀ
stituents in the 5,15ꢀpositions (compounds VII and
VIII) leads to an upfield shift of the signals of С4Н9
substituents as compared with unsubstituted Ni2+ porꢀ
553 (3.80) 523 (4.50)
be evidence that the ionic radius of the Ni(Solv)4Cl2
solvate complex matches the size of the porphyrin
reaction site to a lesser extent than the Pd(Solv)4Cl2
ionic radius.
phyrinate V.
ACKNOWLEDGMENTS
This work was supported by the Russian Foundaꢀ
tion for Basic Research (project no. 11ꢀ03ꢀ00003ꢀa),
the Seventh Framework Program of the European
Community for Research, Technological Developꢀ
ment and Demonstration Activities (IRSESꢀGAꢀ
2009ꢀ247260), and the Federal Target Program “Sciꢀ
entific and ScientificꢀPedagogical Personnel of Innoꢀ
vative Russia” for 2009–2013 (State Contract
no. 02.740.11.0857).
The opposite pattern is observed of porphyrazines.
The formation rate of Ni2+ octaphenyltetraazaporꢀ
phyrinates is higher than that of Pd2+ octaphenyltetꢀ
raazaporphyrinates [9]. The complexation reaction
rate of tetraazaporphyrins with metal salts in strongly
coordinating basic solvents is determined by the
strength of the N–H bonds of the reaction site [8].
Electronꢀdonor substituents in the porphyrazine molꢀ
ecule enhance the polarization of the N–H bonds
and, thus, promote its coordination to NiCl2 in DMF.
Under comparable conditions, Ni2+ octaphenylporꢀ
phyrinate is formed in DMF upon heating under
reflux for 1 min, whereas Ni2+ octa(4ꢀnitrophenyl)tetꢀ
raazaprophyrinate is formed at room temperature in
20 min [7]. The nitrogen mesoꢀatoms in tetraazaporꢀ
phyrins have electronꢀwithdrawing properties; thereꢀ
fore, Ni2+ 5,15ꢀdiazaporphyrinate VI is formed about
a order of magnitude faster than mesoꢀunsubstituted
REFERENCES
1. Porphyrins: Spectroscopy, Electrochemistry, Application,
Ed. by N. S. Enikolopyan (Nauka, Moscow, 1987) [in
Russian].
2. M. Engeser, L. Fabbrizzi, M. Licchelli, and D. Sacchi,
J. Chem. Soc., Chem. Commun. 18, 1191 (1999).
3. N. V. Chizhova, O. V. Toldina, and N. Zh. Mamarꢀ
dashvili, Russ. J. Inorg. Chem. 53, 1401 (2008).
4. N. Zh. Mamardashvili, A. S. Semeikin, O. A. Golubꢀ
chikov, and B. D. Berezin, Zh. Org. Khim. 29, 1213
(1993).
5. B. D. Berezin, Coordination Compounds of Porphyrins
and Phthalocyanines (Wiley, New York, 1981).
6. N. V. Chizhova and A. O. Romanova, Russ. J. Inorg.
Chem. 52, 1713 (2007).
7. N. V. Chizhova, O. G. Khelevina, and B. D. Berezin,
Russ. J. Gen. Chem. 73, 1645 (2003).
Ni2+ porphyrinate
Compounds V–VIII were identified by elemental
V.
1
analysis, UV and IR spectroscopy, and H NMR.
Going from nickel porphyrinates to palladium porꢀ
phyrinates is accompanied by a hypsochromic shift of
absorption bands I and II in the UV spectrum (a specꢀ
tral criterion of strength indicating the strengthening
of the M
←
N
σ
bond and M
→
N
π
donation) [9].
However, the Soret bands of palladium porphyrinates
are bathochromically shifted by 1–3 nm as compared
8. B. D. Berezin and O. G. Khelevina, Porphyrins: Strucꢀ
ture, Properties, and Synthesis (Nauka, Moscow, 1985)
[in Russian].
with corresponding nickel porphyrinates
V–VIII
(table). Previously [10], anomalous spectral properties
have been observed for Ni2+ tetrabenzoporphyrinate in
a mixed sulfuric acid–dimethyl sulfoxide solvent. The
substitution of nitrogen atoms for two mesoꢀcarbon
atoms leads to the hypsochromic shift of the bands in
the UV spectrum of nickel porphyrinates (compounds
9. B. D. Berezin and N. S. Enikolopyan, Metalloporphyꢀ
rins (Nauka, Moscow, 1988) [in Russian].
10. B. D. Berezin, T. I. Potapova, R. A. Petrova, and
Z. A. Tepikina, Izv. Vyssh. Uchebn. Zaved., Khim.
Khim. Tekhnol. 30 (1), 52 (1987).
11. A. S. Semeikin, N. Zh. Mamardashvili, A. V. Glaꢀ
zunov, et al., Izv. Vyssh. Uchebn. Zaved., Khim.
Khim. Tekhnol. 33 (9), 12 (1990).
V
and VI). The introduction of bromine atoms in the
para positions of the phenyl rings (compounds VII and
VIII) leads to a bathochromic shift of band II and to
Translated by G. Kirakosyan
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 58 No. 5 2013