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A zinc(II) complex‐conjugated polymer for selective recognition and separation of phosphates
Author(s) -
Aoki Shin,
Jikiba Akiko,
Takeda Kei,
Kimura Eiichi
Publication year - 2004
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.773
Subject(s) - cyclen , chemistry , zinc , aqueous solution , copolymer , polymer , polymer chemistry , polymerization , ethylene glycol , nuclear chemistry , inorganic chemistry , stereochemistry , organic chemistry
A new polymer, Zn 2+ –cyclen complex‐conjugated polymer 4 (cyclen = 1,4,7,10‐tetraazacyclododecane), was synthesized by copolymerization of a Zn 2+ –(4‐vinyl)benzylcyclen complex ( 3 , ZnL 2 ) with ethylene glycol dimethacrylate (EGDMA). The contents of the zinc(II) ions in Zn 2+ –cyclen polymer 4 were determined as 36–42 μmol g −1 , utilizing a Zn 2+ ‐selective fluorophore, dansylamidoethylcyclen 10 (L 3 ). It was found that 31% of deoxyadenosine 5′‐monophosphate (5′‐dAMP) (50 μ M ) is adsorbed on 4 (corresponding to 50 μ M ) in 20 m M HEPES (pH 7.0) with I = 0.1 (NaNO 3 ) at 25°C. The apparent complexation constants for the 1:1 complex of ZnL 2 on 4 with 5′‐dAMP and 4‐NPP, log K app (ZnL–S 2− ) (S 2− denotes a phosphomonoester dianion), at pH 7.0 and 25°C were determined as 4.1±0.1, which was larger than that (3.5) for the 1:1 complex of 3 (ZnL 2 ) with 5′‐dAMP in homogeneous aqueous solution at pH 7.0 and 25°C. Deoxyadenosine (dA) and adenosine 3′,5′‐cyclic‐monophosphate (3′,5′‐cAMP), a cyclic phosphodiester monoanion, were negligibly adsorbed on Zn 2+ –cyclen polymer 4 , implying that 4 interacts selectively with phosphomonoester dianions. For reference, Zn 2+ ‐free polymer 8 (prepared from 4 ) and control polymer 9 (prepared by copolymerization of styrene with EGDMA) hardly adsorbed 5′‐dAMP, dA and 3′,5′‐cAMP. High‐performance liquid chromatography (HPLC) of mononucleotides such as 5′‐dAMP, cytidine 5′‐monophosphate (5′‐CMP), guanosine 5′‐monophosphate (5′‐GMP), and thymidine 5′‐monophosphate (5′‐dTMP) was achieved using 4 as a stationary phase and continuous gradient elution with 10:90 MeOH–1 m M HEPES (pH 7.0) and 10:90 MeOH–1 m M HEPES+10 m M (NH 4 ) 2 HPO 4 (pH 7.0). As expected, the retention times of mononucleotides were larger than those of the corresponding nucleosides, owing to the Zn 2+ ‐phosphate interactions. These results indicated that Zn 2+ –cyclen‐conjugated polymer 4 affords a strong methodology to detect and separate biologically important phosphates. Copyright © 2004 John Wiley & Sons, Ltd.