Synthesis and characterization of novel porphyrinogen-like macrocycle schiff base ligands

Article abstract of DOI:10.1081/SCC-200043208

In this paper, two novel porphyrinogen-like macrocycle ligands were synthesized and characterized with elemental analyses, ¹H NMR, FAB-Ms, and IR methods.

Full text of DOI:10.1081/SCC-200043208

SYNTHETIC COMMUNICATIONSw
Vol. 34, No. 24, pp. 4517–4520, 2004
Synthesis and Characterization of Novel
Porphyrinogen-Like Macrocycle Schiff
Base Ligands
*
Jinfu Zheng, Xugang Guo, and Zhengyin Yang
State Key Laboratory of Applied Organic Chemistry,
College of Chemistry and Chemical Engineering Lanzhou University,
Lanzhou, Gansu, P.R China
ABSTRACT
In this paper, two novel porphyrinogen-like macrocycle ligands were
synthesized and characterized with elemental analyses, 1H NMR,
FAB-Ms, and IR methods.
Key Words: Macrocycle schiff base; Porphyrinogen-like.
Novel pyrrole-containing macrocycle schiff bases have distinctive struc-
tures and properties. They are currently attracting interest because they may
*
Correspondence: Zhengyin Yang, State Key Laboratory of Applied Organic
Chemistry, College of Chemistry and Chemical Engineering Lanzhou University,
Lanzhou, Gansu 730000, P.R China; E-mail: yangzy@lzu.edu.cn.
4517
DOI: 10.1081/SCC-200043208
0039-7911 (Print); 1532-2432 (Online)
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Copyright # 2004 by Marcel Dekker, Inc.

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Zheng, Guo, and Yang
display unusual physical, chemical, or coordination properties, and play
important roles in a number of areas in chemistry and biochemistry.[1–3]
The porphyrin-like macrocycle and their rare earth metal complexes belong
to a novel family of dye molecules, absorb strongly around 760–780 nm,
and were suggested as potential photosensitizers for Photo Dynamic
Therapy.[3] As we know, the formation of macrocyclic complexes depends
significantly on the dimension of the internal cavity, on the rigidity of the
macrocycle, on the nature of its donor atoms, and on the complexing proper-
ties of the anion involved in the coordination.[4] In this article we report the
synthesis of two novel porphyrinogen-like macrocycle schiff base ligands
with different internal cavities.
EXPERIMENTAL
Elemental analyses were determined with the Elementar Vario EL
elemental analyzers. NMR spectra were obtained in CDCl3 with Me4Si as
an internal standard. All melting points were uncorrected. All yields refer to
isolated products.
3-Bromoformylbenzene (12 mmol) and 2-(ethoxycarbony1)-3,4-dimethyl-
pyrrole[4] (24 mmol) were dissolved with heating in 40mL absolute EtOH.
The reaction mixture was then heated to reflux, and 1.2 mL of 6 mol/L HCL
was added. The reaction was placed under N2 and refluxed for 1 h. Upon
cooling, the product crystallized. It was filtrated, washed with cold EtOH,
1
and dried to yield 4.57g (76%) of 2 H NMR: d 7.26 (4H, m, 4 ꢀ ArH,
2 ꢀ NH), d 5.50 (1H, s, CH), d 4.07 (4H, q, CH2CH3), d 2.23 (6H, s, CH3),
d 1.93 (6H, s, CH3), d 1.3 (12H, t, CH2CH3).
Ten mmol of 2 was suspended in 60 mL of absolute EtOH and brought to
reflux. A total of 5 mL of 5 M NaOH solution was added, and the reaction
mixture was refluxed for 20 h under N2. The EtOH was removed under
reduced pressure, and the residue was diluted with 100 mL of H2O and
filtrated. The filtrate was acidified with glacial HOAc, and the diacid was pre-
cipitated as a pink solid. The pink solid was dissolved in 60 mL of degassed
ethanolamine. The mixture was placed under N2 and refluxed for 2 h, after
which the reaction mixture was poured into 80 mL of ice H2O while still
warm. A solid soon separated, which was filtrated and dried to yield 3.11 g
1
(87%) of 3. H NMR: d 7.20 (6H, m, 4 ꢀ ArH, 2 ꢀ NH), d 6.32 (2H, s, a
H), d 5.38 (1H, s, CH), d 2.01 (6H, s, CH3), d 1.87 (6H, s, CH3).
Ten mmol of 3 was added to 30 mL of DMF. The mixture was cooled
to 258C, then 12 mL of POCl3 was added, after which, the reaction mixture
was stilled for 12 h under room temperature. The reaction mixture was
placed under 508C–608C and refluxed for 2 h, after which the reaction

Synthesis of Novel Porphyrinogen-Like Macrocycle Schiff Base Ligands
4519
mixture was poured into 100 mL of ice H2O while still warm. The filtrate was
basified with 5 M NaOH to pH ¼ 9, a brown solid separated, which was fil-
1
trated and dried to yield 2.02 g (49%) of 4. H NMR: d 9.30 (2H, s, CHO),
d 7.20 (6H, m, 4 ꢀ ArH, 2 ꢀ NH), d 5.25 (1H, s, CH), d 2.25 (6H, s, CH3),
d 1.90 (6H, S, CH3).
One mmol of 4 was dissolved with heating in 50mL CH3OH. The reaction
mixture was then heated to reflux, 50mL NH2–R–NH2(R1 ¼ –CH2CH2CH2–,
R2 ¼ –CH2CH2NHCH2CH2–) of CH3OH solution (2.0 ꢀ 1022 mol/L) was
then added tardily. The reaction mixture was refluxed for 4 h. The CH3OH
was removed under reduced pressure. The residue was filtrated and recrystal-
lized with CH3OH, dried to yield 0.37g (82%) of H4L1 and 0.41g (81%) of
H4L2. H4L1, C48H54N8Br2, [Found: C, 63.87 (63.86), H, 5.85 (6.03), N, 12.24
(12.41)] 1H NMR: d 8.01 (4H,s, HC55N) d 7.11 (12H, m, 8 ꢀ ArH,
4 ꢀ NH), d 5.50 (2H, s, CH), d 3.50 (8H, t, CH2), d 2.09 (12H, s, CH3),
d 2.01 (12H, s, CH3), d 1.22 (4H, tt, CH2). FAB-MS m/z: 905 [H4L1 þ H]þ.
The melting point of H4L1 is 267–2688C.

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Zheng, Guo, and Yang
H4L2, C50H60N10Br2, [Found: C, 62.87 (62.50), H, 6.18 (6.25), N, 14.06
(14.58)]. 1H NMR: d 8.05 (4H, s, HC55N) d 7.16 (12H, m, 8 ꢀ ArH, 4 ꢀ NH),
d 5.53 (2H, s, CH), d 4.82 (2H, t, NH), d 3.53 (8H, t, CH2), d 2.30 (8H, t, CH2),
d 2.06 (12H, s, CH3), d 1.98 (12H, s, CH3). FAB-MS m/z: 963 [H4L2 þ H]þ.
TG-DTG shows that H4L2 begins to decompose at 2548C; the melting point of
the ligand is not found.
ACKNOWLEDGMENT
Project supported by the National Natural Science Foundation
(29975012).
REFERENCES
1. Lehn, J.M. Supramolecular Chemistry; V.C.H.: Weinheim, Germany, 1995.
2. Ragunathan, K.G.; Bharadwaj, P.K. Template synthesis of a cryptand with
hetero-ditopic receptor sites. Tetrahedron Lett. 1992, 33 (49), 7581.
3. Sessler, J.L. Synthesis and crystal structure of a novel tripyrrane-contain-
ing porphyrinogen-like macrocycle. J. Org. Chem. 1987, 52 (19),
4394–4397.
4. Helms, A.; Heiler, D.; McLendon, G. Electron transfer in bis-porphyrin
donor-acceptor compounds with polyphenylene spacers shows a weak
distance dependence. J. Am. Chem. Soc. 1992, 114 (15), 6227.
Received in Japan April 22, 2004