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Article: The effects of microenvironment polarity and dendritic branching of aliphatic hydrocarbon dendrons on the self-assembly of 2-ureido-4-pyrimidinones

TitleThe effects of microenvironment polarity and dendritic branching of aliphatic hydrocarbon dendrons on the self-assembly of 2-ureido-4-pyrimidinones
Authors
KeywordsDendrimers
Dimerization
Self-assembly
Solvatochromism
Tautomerism
Issue Date2010
PublisherWiley - V C H Verlag GmbH & Co. KGaA. The Journal's web site is located at http://www.wiley-vch.de/publish/en/journals/alphabeticIndex/2451
Citation
Chemistry - An Asian Journal, 2010, v. 5 n. 10, p. 2249-2257 How to Cite?
AbstractTwo series of aliphatic hydrocarbon-based G1-G3 dendritic 2-ureido-4-pyrimidinones (UPy) (S-Gn)2 and (L-Gn)2, differing from one another by the distance between the branching juncture to the urea end, were prepared and characterized. These hydrocarbon dendrons were also appended to a p-aminonitrobenzene solvatochromic chromophore in order to probe their microenvironment polarity. While positive solvatochromism was observed which indicated the chromophore was solvent accessible, there was no significant difference between the microenvironment polarities on going from the G1 to the G3 dendrons. The self-assembling behavior and tautomeric preference of the dendritic UPy derviatives were examined by 1H NMR spectroscopy. The dimerization constants (Kdim*) of the DDAA tautomers were unchanged at 107m-1 in CDCl3 at both 25 and 50 °C, which were comparable to those of UPy compounds bearing other nonpolar substitutents. Furthermore, the lower limits on the K′dim* of the DADA tautomeric forms of the (S-Gn)2 and (L-Gn)2 series were determined to be 106 and 105m-1 in CDCl 3, respectively. It was found that a closer proximity of the dendron branching juncture to the UPy unit could lead to a destabilization effect on the dimeric states. Hence, the (L-Gn)2 dimers are more stable than those of (S-Gn)2 in the DDAA form, but the latter are more stable than the former in the tautomeric DADA state. This study showed that both the highly nonpolar microenvironment and the proximity of the dendritic branching juncture to the UPy motif could alter the strength and profile of the hydrogen bond-mediated self-assembling process. © 2010 Wiley-VCH Verlag GmbH&Co. KGaA, Weinheim.
Persistent Identifierhttp://hdl.handle.net/10722/133606
ISSN
2015 Impact Factor: 4.592
2015 SCImago Journal Rankings: 1.833
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorWong, CHen_HK
dc.contributor.authorChoi, LSen_HK
dc.contributor.authorYim, SLen_HK
dc.contributor.authorLau, KNen_HK
dc.contributor.authorChow, HFen_HK
dc.contributor.authorHui, SKen_HK
dc.contributor.authorSze, KHen_HK
dc.date.accessioned2011-05-24T02:11:39Z-
dc.date.available2011-05-24T02:11:39Z-
dc.date.issued2010en_HK
dc.identifier.citationChemistry - An Asian Journal, 2010, v. 5 n. 10, p. 2249-2257en_HK
dc.identifier.issn1861-4728en_HK
dc.identifier.urihttp://hdl.handle.net/10722/133606-
dc.description.abstractTwo series of aliphatic hydrocarbon-based G1-G3 dendritic 2-ureido-4-pyrimidinones (UPy) (S-Gn)2 and (L-Gn)2, differing from one another by the distance between the branching juncture to the urea end, were prepared and characterized. These hydrocarbon dendrons were also appended to a p-aminonitrobenzene solvatochromic chromophore in order to probe their microenvironment polarity. While positive solvatochromism was observed which indicated the chromophore was solvent accessible, there was no significant difference between the microenvironment polarities on going from the G1 to the G3 dendrons. The self-assembling behavior and tautomeric preference of the dendritic UPy derviatives were examined by 1H NMR spectroscopy. The dimerization constants (Kdim*) of the DDAA tautomers were unchanged at 107m-1 in CDCl3 at both 25 and 50 °C, which were comparable to those of UPy compounds bearing other nonpolar substitutents. Furthermore, the lower limits on the K′dim* of the DADA tautomeric forms of the (S-Gn)2 and (L-Gn)2 series were determined to be 106 and 105m-1 in CDCl 3, respectively. It was found that a closer proximity of the dendron branching juncture to the UPy unit could lead to a destabilization effect on the dimeric states. Hence, the (L-Gn)2 dimers are more stable than those of (S-Gn)2 in the DDAA form, but the latter are more stable than the former in the tautomeric DADA state. This study showed that both the highly nonpolar microenvironment and the proximity of the dendritic branching juncture to the UPy motif could alter the strength and profile of the hydrogen bond-mediated self-assembling process. © 2010 Wiley-VCH Verlag GmbH&Co. KGaA, Weinheim.en_HK
dc.languageengen_US
dc.publisherWiley - V C H Verlag GmbH & Co. KGaA. The Journal's web site is located at http://www.wiley-vch.de/publish/en/journals/alphabeticIndex/2451en_HK
dc.relation.ispartofChemistry - An Asian Journalen_HK
dc.subjectDendrimersen_HK
dc.subjectDimerizationen_HK
dc.subjectSelf-assemblyen_HK
dc.subjectSolvatochromismen_HK
dc.subjectTautomerismen_HK
dc.titleThe effects of microenvironment polarity and dendritic branching of aliphatic hydrocarbon dendrons on the self-assembly of 2-ureido-4-pyrimidinonesen_HK
dc.typeArticleen_HK
dc.identifier.openurlhttp://library.hku.hk:4550/resserv?sid=HKU:IR&issn=1861-4728&volume=5&issue=10&spage=2249&epage=2257&date=2010&atitle=The+effects+of+microenvironment+polarity+and+dendritic+branching+of+aliphatic+hydrocarbon+dendrons+on+the+self-assembly+of+2-ureido-4-pyrimidinones-
dc.identifier.emailSze, KH:khsze@hku.hken_HK
dc.identifier.authoritySze, KH=rp00785en_HK
dc.description.naturelink_to_subscribed_fulltext-
dc.identifier.doi10.1002/asia.201000359en_HK
dc.identifier.pmid20677322-
dc.identifier.scopuseid_2-s2.0-77957592198en_HK
dc.identifier.hkuros185370en_US
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-77957592198&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume5en_HK
dc.identifier.issue10en_HK
dc.identifier.spage2249en_HK
dc.identifier.epage2257en_HK
dc.identifier.isiWOS:000283272000015-
dc.publisher.placeGermanyen_HK
dc.identifier.scopusauthoridWong, CH=36571167200en_HK
dc.identifier.scopusauthoridChoi, LS=36570144000en_HK
dc.identifier.scopusauthoridYim, SL=36571293100en_HK
dc.identifier.scopusauthoridLau, KN=25221872700en_HK
dc.identifier.scopusauthoridChow, HF=7102303384en_HK
dc.identifier.scopusauthoridHui, SK=13406279000en_HK
dc.identifier.scopusauthoridSze, KH=7006735061en_HK

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