Lanthanide complexes with acetylacetonate and 5,10,15,20-tetra[para-(4-fluorobenzoyloxy)-meta-methoxy]phenylporphyrin

Article abstract of DOI:10.1081/SIM-120003789

Lanthanide complexes of acetylacetonate and 5,10,15,20-tetra [para-(4-fluorobenzoyloxy)-meta-methoxy]phenylporphyrin having the general formula Ln[(FBOMP)₄P](acac) (where Ln=Er, Tm, Yb; FBOMP=[para-(4-fluorobenzoyloxy)-meta-methoxy]phenyl; acac=acetylacetone; P=porphyrin) have been prepared and characterized. A structure is proposed in which one 5,10,15,20-tetra[para-(4-fluorobenzoyloxy)- meta-methoxy]porphyrin molecule is coordinated to a rare earth ion in a tetradentate fashion, while one acetylacetonate molecule is coordinated to the same metal ion in a bidentate fashion.

Full text of DOI:10.1081/SIM-120003789

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LANTHANIDE COMPLEXES WITH ACETYLACETONATE AND
5,10,15,20-TETRA[PARA-(4-FLUOROBENZOYLOXY)-
META-METHOXY]PHENYLPORPHYRIN
Zhi Xin Zhao a & Guo Fa Liu b
a Department of Chemistry, Jilin University, Changchun, 130023, People's Republic of China
b Department of Chemistry, Jilin University, Changchun, 130023, People's Republic of China
Published online: 15 Feb 2007.
To cite this article: Zhi Xin Zhao & Guo Fa Liu (2002) LANTHANIDE COMPLEXES WITH ACETYLACETONATE AND 5,10,15,20-
TETRA[PARA-(4-FLUOROBENZOYLOXY)-META-METHOXY]PHENYLPORPHYRIN, Synthesis and Reactivity in Inorganic and Metal-
Organic Chemistry, 32:3, 465-473, DOI: 10.1081/SIM-120003789
To link to this article: http://dx.doi.org/10.1081/SIM-120003789
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SYNTH. REACT. INORG. MET.-ORG. CHEM., 32(3), 465–473 (2002)
LANTHANIDE COMPLEXES WITH
ACETYLACETONATE AND
5,10,15,20-TETRA[PARA-(4-
FLUOROBENZOYLOXY)-META-
METHOXY]PHENYLPORPHYRIN
Zhi Xin Zhao and Guo Fa Liu*
Department of Chemistry, Jilin University,
Changchun, 130023, People’s Republic of China
ABSTRACT
Lanthanide complexes of acetylacetonate and 5,10,15,20-tetra
[ para-(4-fluorobenzoyloxy)-meta-methoxy]phenylporphyrin
having the general formula Ln[(FBOMP)4P](acac) (where
Ln ¼ Er, Tm, Yb; FBOMP ¼ [ para-(4-fluorobenzoyloxy)-
meta-methoxy]phenyl; acac ¼ acetylacetone; P ¼ porphyrin)
have been prepared and characterized. A structure is propo-
sed in which one 5,10,15,20-tetra[ para-(4-fluorobenzoyloxy)-
meta-methoxy]porphyrin molecule is coordinated to a rare
earth ion in a tetradentate fashion, while one acetylacetonate
molecule is coordinated to the same metal ion in a bidentate
fashion.
*Corresponding author. E-mail: guofaliu@163.com
465
Copyright # 2002 by Marcel Dekker, Inc.
www.dekker.com

466
ZHAO AND LIU
INTRODUCTION
The synthesis and characterization of porphyrins and metallopor-
phyrins have been studied extensively1. As a model of hemoglobin, myo-
globin, and cytochrome P450, they have been used extensively as
oxygenation catalysts2. However, in general, this research work is limited to
transition metalporphyrin complexes. Since Wong3 synthesized the first
lanthanide porphyrin in 1974, which is tetraphenylporphyrineuropium(III),
the new field of porphyrin complexes has been developed rapidly. Owing to
the unique electronic and magnetic properties of lanthanide porphyrins,
trivalent lanthanide ions represent environmental probes which potentially
may be even more versatile than transition metal ions4. Since lanthanide
ions have characteristic spectroscopic and magnetic properties, their inser-
tion into heme proteins provides a potentially powerful new class of metal-
centered probes5. In this paper, we report the meso-substituted lanthanide
complexes of acetylacetonate-5,10,15,20-tetra[ para-(4-fluorobenzoyloxy)-
meta-methoxy]phenylporphyrin, Ln[(FBOMP)4P]acac (where Ln ¼ Er, Tm,
Yb; FBOMP ¼ [ para-(4-fluorobenzoyloxy)-meta-methoxy]phenyl; acac ¼
acetylacetone) which have been characterized by NMR, IR, UV-Vis,
molar conductances, elemental analyses. The structure of the ligand,
H2(FBOMP)4P, is shown in Fig. 1.
Figure 1. Structure of the ligand H2(FBOMP)4P.

LANTHANIOLE COMPLEXES
RESULTS AND DISCUSSION
Composition of the Complexes
467
The reaction of rare earth acetylacetonate complexes with 5,10,15,20-
tetra[para-(4-fluorobenzoyloxy)-meta-methoxy]porphyrin in 1,2,4-trichloro-
benzene may be represented by the following equation:
H2ðFBOMPÞ4P þ LnðacacÞ3 ! Ln½ðFBOMPÞ4PꢀðacacÞ þ 2Hacac
The elemental analyses for carbon, hydrogen, nitrogen, empirical
formulas, formula weights, yields and the decomposition temperatures of
the prepared complexes are given in Table I.
UV-Visible Spectra
The maximum absorption values (lmax) of the ligand and complexes
are shown in Table II. Compared with the ligand, H2(FBOMP)4P, the
number of the absorption bands of the complexes decreases and the
absorption bands exhibit small shifts to longer wave lengths. The absorption
bands in the Q-band region are designated as I, II, III, IV from red to blue.
The UV spectra of the complexes show bands characteristic of metallo-
porphyrins6,7
.
Table I. Characterization Data of the Compoundsa
Dec.
Yield temp.
Empirical Formula
(Formula Weight)
Compounds
%Ca %Ha %Na (%)
(ꢁC)
H2(FBOMP)4
C76H50N4O12F4
1286
70.88
(70.91) (3.89) (4.35)
62.68 3.54 3.65
(62.71) (3.55) (3.61)
62.61 3.56 3.64
(62.63) (3.54) (3.61)
62.45 3.52 3.62
(62.47) (3.53) (3.60)
3.88
4.37
12
65
67
62
> 300
Er[(FBOMP)P]4acac
ErC81H55N4O14F4
1550
Tm[(FBOMP)P]4acac TmC81H55N4O14F4
> 300
> 300
> 300
1552
Yb[(FBOMP)P]4acac YbC81H55N4O14F4
1556
aCalculated values are given in parentheses.

468
ZHAO AND LIU
Table II. UV-Vis Spectra of the Ligand and Complexes
Max. absorption peaks (lmax nm); Emax(l molꢂ1 cmꢂ1 a
Soret IV III II
)
Compounds
I
H2(FBOMP)4P
421
516
551
590.5
646.5
(3.45 ꢄ 105) (2.64 ꢄ 104) (1.47 ꢄ 103) (7.26 ꢄ 103) (4.13 ꢄ 103)
Er[(FBOMP)4P]acac 427
519
555
594
(3.15 ꢄ 105) (5.54 ꢄ 103) (2.12 ꢄ 104) (9.38 ꢄ 103)
Tm[(FBOMP)4P]acac 425
519
556
594
(3.51 ꢄ 105) (5.48 ꢄ 103) (2.35 ꢄ 104) (9.59 ꢄ 103)
Yb[(FBOMP)4P]acac 424
518.5
555
594
(3.91 ꢄ 105) (5.27 ꢄ 103) (2.53 ꢄ 104) (9.17 ꢄ 103)
aMolar extinction coefficient values are given in parentheses.
Infrared Spectra
The important band frequencies and assignments of the ligand and
complexes are presented in Table III. The bands at 3317 and 976 cmꢂ1 in the
free porphyrin, H2(FBOMP)4P, are due to the N-H stretching and bending
vibration of the porphyrin core. The N-H stretching and bending vibration
bands are absent in the complexes, since the hydrogen atoms are replaced by
the lanthanide ion to form Ln-N bonds. The bands of the complexes in the
range 4127415 cmꢂ1 are assigned to the Ln-O stretching vibration8. The
bands at 1510 cmꢂ1 in the complexes which do not exist in the free por-
phyrin and transition metalporphyrin complexes are assigned to the C-C
stretching vibration of the coordinated acetylacetonate ring9. The appear-
ance of the C-C band and the formation of Ln-O bonds in the acet-
ylacetonate ring indicate that an acetylacetonate ring is coordinated to the
lanthanide ion. Assignments of other absorption bands are also presented in
Table III.
Molar Conductances
The molar conductance values of the Tb, Ho, Er, Tm complexes and
the ligand H2(FBOMP)4P are 1.50, 1.67, 1.82 and 0.15 Oꢂ1ꢃcm2ꢃmolꢂ1
,
respectively. It is clear that all of the complexes and ligand show non-
electrolytic behaviour10.

LANTHANIOLE COMPLEXES
469

470
ZHAO AND LIU
1H NMR Spectra
The 1H NMR chemical shift values in deuterated chloroform (d, ppm)
for the ligand H2(FBOMP)4P are at 9.01 (8H, pyrrole ring); 7.89, 8.44 (12H,
meso-phenyl protons); 7.56 (8H, fluorophenyl-2,6 protons); 7.26 (8H,
fluorophenyl-3,5 protons); 4.36, 4.40 (12H, phenylmethoxy protons) and
ꢂ2.78 (2H, pyrrole N-H). In the complex Er[(FBOMP)4P]acac, the signal at
ꢂ2.78 (2H, pyrrole N-H) disappears, since the hydrogen atom in the N-H
bond is replaced by the rare earth Er ion, and the signal at 2.47 (6H,
acetylacetonate CH3) appears, the latter being due to methyl groups of the
coordinated acetylacetonate ring. The disappearance of the signal at
ꢂ2.78 ppm and the appearance of the signal peak at 2.47 ppm indicate that
the ligands, porphyrin and acetylacetone, are all coordinated to the lan-
thanide ion. Other peaks of the complex Lu[(FBOMP)4P]acac are broad-
enced as compared to those of the ligand H2(FBOMP)4P.
Conclusions
From the above results, we may draw the following conclusions: One
molecule of the ligand porphyrin, H2(FBOMP)4P, is coordinated to a rare
earth ion in a tetradentate fashion and one acetylacetone, acac, is coordi-
nated to the same rare earth ion in a bidentate fashion. Therefore, the
coordination number of the central rare earth ion is six and the general
formula of the complexes may be represented as Ln[(FBOMP)4P](acac). The
lanthanide ion is expected to lie above the porphyrin plane of the ring
(Fig. 2)3.
EXPERIMENTAL
Reagents and Materials
Pyrrole (C.P. chemical purity), 4-hydroxy-3-methoxybenzaldehyde
(A.R. analytical reagent), 1,2,4,-trichlorobenzene (A.R.), chloroform
(A.R.), absolute ethanol (A.R.), ethyl acetate (A.R.), 4-fluorobenzoic acid
(A.R.), thionyl chloride (A.R.), neutral aluminum oxide (807200 mesh), rare
earth oxide (99.90%799.95%), acetylacetone (A.R.), triethylamine (A.R.).
The lanthanide acetylacetonate complexes Ln(acac)3 (Ln ¼ Er, Tm, Yb;
Hacac¼ acetylacetone) were prepared and purified according to the litera-
ture11. The 5,10,15,20-tetra(para-hydroxy-meta-methoxy)phenylporphyrin,

LANTHANIOLE COMPLEXES
471
Figure 2. Suggested structure of the complex Ln[(FBOMP)4P](acac).
H2(THMP)4P, [THMP ¼ ( para-hydroxy-meta-methoxy)phenyl; P ¼ porphy-
rin] was prepared by the literature method12. 4-Fluorobenzoyl chloride was
prepared by the reaction of the 4-fluorobenzoic acid and thionyl chloride.
5,10,15,20-tetra[para-(4-fluorobenzoyloxy)-meta-methoxy]porphyrin, H2(FB-
OMP)4P, [FBOMP ¼ ( para-hydroxy-meta-methoxy)phenyl; P ¼ porphyrin],
was prepared by the reaction of tetra( para-hydroxy-meta-methoxy)phenyl-
porphyrin, H2(THMP)4P, and 4-fluorobenzoyl chloride.
Apparatus and Measurements
Elemental analyses were measured by a Perkin7Elmer 240 C auto
elementary analyser. Infrared spectra were recorded on a Nicolet 5PC-FT-
IR spectrometer using KBr pellets in the region 20074000 cmꢂ1. UV-Visible
spectra were recorded on a Shimadzu UV-240 spectrophotometer using
chloroform (for the ligand) and ethanol (for the complexes) as solvents.
Molar conductances of 10ꢂ3molꢃLꢂ1 solutions in chloroform (for the ligand)
and ethanol (for the complexes) at 25 ꢁC were measured on a DDX-111A
1
conductometer. The H NMR spectra were recorded in deuterated chloro-
form using a Varian-Unity-400 NMR spectrometer and employing tetra-
methylsilane as internal reference.

472
ZHAO AND LIU
Synthesis of the 5,10,15,20-Tetra[ para-(4-fluorobenzoyloxy)-meta-
methoxy]phenylporphyrin H2(FBOMP)4P
H2(THMP)4P (2.00 g, 1.56 mmol) was dissolved in 150 mL of hot
benzene and triethylamine (2.74 mL, 15.6 mmol) was added. A solution of 4-
fluorobenzoyl chloride (2.94 mL, 24.8 mmol) in 50 mL benzene was added
dropwise to the above solution in the course of two hours with stirring at
70 ꢁC. The reaction solution then was refluxed for eight hours and cooled to
room temperature. Benzene was removed under reduced pressure. Then
distilled water (200 mL) was added to the reaction mixture and extracted
three times with freshly distilled chloroform (200 mL). The extract was
washed three times with distilled water (200 mL). The chloroform solution
was concentrated and applied to a neutral aluminum oxide column
(2.5 ꢄ 15 cm). The first band containing H2(FBOMP)4P was eluted by
chloroform. The chloroform fraction was concentrated and cooled. The
precipitated product was dried in vacuo. The yield was 1.81 g. (90%)
Synthesis of the Lanthanide Acetylacetonate-5,10,15,20-tetra[ para-
(4-fluorobenzoyloxy)-meta-methoxy]phenylporphyrin Complexes
Ln[(FBOMP)4P](acac)
The
lanthanide
acetylacetonate-5,10,15,20-tetra[ para-(4-fluoro-
benzoyloxy)-meta-methoxy]phenylporphyrin complexes Ln[(FBOMP)4P]-
(acac) (Ln ¼ Er, Tm, Yb) were prepared by the reaction of lanthanide
acetylacetonate complexes Ln(acac)3 (0.60 g, 1.2571.27 mmol) with the
ligand H2(FBOMP)4P (0.30 g, 0.233 mmol) in 1,2,4-trichlorobenzene
(40 mL) at 215 ꢁC with stirring under the protection of a dry nitrogen stream
for about four hours. The progress of the reaction was followed by mea-
suring the UV-Visible spectrum of the reaction solution every hour. The
reaction mixture then was chromatographed on a neutral aluminum oxide
column (1.5 ꢄ 15 cm). The first band containing a small amount of
H2(FBOMP)4P was eluted by chloroform. The second band eluted by ethyl
acetate contained the desired complexes, Ln[(FBOMP)4P]acac. The ethyl
acetate fraction was concentrated and dried under vacuo. The purple crude
products were recrystallized from absolute ethanol.
ACKNOWLEDGMENT
We thank the National Natural Science Foundation of China for
financial support of this work.

LANTHANIOLE COMPLEXES
REFERENCES
473
1. Gouterman, M. In The Porphyrins; Dolphin, D. Ed.; Academic Press:
New York, 1978, 3, 17165.
2. Montellano, O.D.P. Cytochrome P-450: Structure, Mechanism and
Biochemistry; Plenum: New York, 1986.
3. Wong, C.P.; Venteicher, R.F.; Horrocks, W. DeW. Jr. Lanthanide
Porphyrin Complexes. A Potential New Class of Nuclear Magnetic
Dipolar Probe. J. Am. Soc. 1974, 96, 714977150.
4. Horrocks, W. Dew. Jr.; Venteicher, T.F.; Spilburg, C.A.; Vallee, B.L.
Lanthanide Porphyrin Probes of Heme Proteins. Insertion of Ytter-
bium(III) Mesoporphyrin IX into Apomyoglobin. Biochem. Biophys.
Res. Commun. 1975, 64, 3177322.
5. Horrocks, W. DeW. Jr.; Wong, C.P. Lanthanide Porphyrin Com-
plexes. Evaluation of Nuclear Magnetic Resonance Dipolar Probe and
Shift Reagent Capabilities. J. Am. Chem. Soc. 1976, 98, 715777162.
6. Liu, G.F.; Shi, T.S.; Liu, X.X. Lanthanide Complexes of Acetylace-
tonate-meso-5-(4-hydroxyphenyl)-10,15,20-tri(4-methoxyphenyl)por-
phyrin. Synth. React. Inorg. Met.-Org. Chem. 1993, 23, 114571153.
7. Liu, G.F.; Shi, T.S.; Liu, X.X. Lanthanide Complexes of Acetyl-
acetonate-meso-tetra(1-naphthyl)tetrabenzoporphyrin. Synth. React.
Inorg. Met.-Org. Chem. 1994, 24, 112771137.
8. Liu, G.F.; Shi, T.S.; Liu, X.X. Lanthanide Complexes with
Acetylancetonate and 5-(4-Hydroxyphenyl)-10,15,20-triphenylpor-
phyrin Ligands. Polyhedron 1994, 13, 225572258.
9. Liu, G.F.; Zhang, Y.F. Infrared and Raman Spectra of Lanthanide
Acetylacetonate-a-b-g-d-tetraphenylporphyrin Complexes. Chem. J.
Chin. Univ. 1984, 5, 7137717; Chem. Abstr. 101, 237537x.
10. Geary, W.J. The Use of Conductivity Measurements in Organic Sol-
vents for the Characterization of Coordination Compounds. Coord.
Chem. Rev. 1974, 7, 817122.
11. Pope, G.W.; Steinbach, J.F.; Wagner, W.F. Characteristics of the
Solvates of the Rare-Earth Acetylacetonates. J. Inorg. Nucl. Chem.
1961, 20, 3047313.
12. Shi, T.S.; Liu, W.; Liu, G.F. Synthesis of Tetra(4-hydroxy-
phenyl)porphyrin Complex. Chinese J. Apll. Chem. 1998, 15, 73775;
Chem. Abstr. 128, 210866v.
Received November 14, 2000
Accepted December 1, 2001
Referee I: J. W. Owens
Referee II: J. E. Bradshaw