Efficient Synthesis of First- and Second-Generation, Water-Soluble Dendronized Polymers

2008 ◽  
Vol 41 (1) ◽  
pp. 43-49 ◽  
Author(s):  
Wen Li ◽  
Afang Zhang ◽  
A. Dieter Schlüter
Keyword(s):  
Second Generation ◽  
Water Soluble ◽  
Efficient Synthesis ◽  
Dendronized Polymers ◽  
First And Second Generation

Synthesis and photophysical properties of water-soluble dendrimers bearing a phthalocyanine core

2007 ◽  
Vol 11 (06) ◽  
pp. 448-454 ◽  
Author(s):  
Masakazu Nishida ◽  
Atsuya Momotake ◽  
Yoshihiro Shinohara ◽  
Yoshinobu Nishimura ◽  
Tatsuo Arai
Keyword(s):  
Aqueous Solution ◽  
Second Generation ◽  
Photophysical Properties ◽  
Dendritic Structure ◽  
Spectroscopic Measurement ◽  
Water Soluble ◽  
Aggregation Behaviors ◽  
First And Second Generation ◽  
Deactivation Process ◽  
Self Aggregation

Aggregation behaviors of phthalocyanine derivatives which have a dendritic structure were examined in an aqueous solution. We prepared the first- and second-generation dendrimers (WG1-PC and WG2-PC), having water-soluble substituents as a peripheral group, to be resolved in water. From spectroscopic measurement, WG2-PC acted in a monomeric manner, even in an aqueous solution, in contrast to WG1-PC, which exhibited spectra attributed to aggregation. This implies that a higher generation of water-soluble dendrimers can prevent a phthalocyanine core from forming an aggregation. The introduction of the second-generation dendrons to an aggregatable core may be effective to avoid self-aggregation and an undesirable deactivation process.

scholarly journals Ozonolysis of <i>α</i>-phellandrene – Part 2: Compositional analysis of secondary organic aerosol highlights the role of stabilised Criegee intermediates

2018 ◽  
Vol 18 (7) ◽  
pp. 4673-4693 ◽  
Author(s):  
Felix A. Mackenzie-Rae ◽  
Helen J. Wallis ◽  
Andrew R. Rickard ◽  
Kelly L. Pereira ◽  
Sandra M. Saunders ◽  
...  
Keyword(s):  
Second Generation ◽  
Secondary Organic Aerosol ◽  
Indirect Evidence ◽  
Compositional Analysis ◽  
Particle Growth ◽  
Organic Aerosol ◽  
Water Soluble ◽  
Formation Mechanisms ◽  
Criegee Intermediates ◽  
First And Second Generation

Abstract. The molecular composition of the water-soluble fraction of secondary organic aerosol (SOA) generated from the ozonolysis of α-phellandrene is investigated for the first time using high-pressure liquid chromatography coupled to high-resolution quadrupole–Orbitrap tandem mass spectrometry. In total, 21 prominent products or isomeric product groups were identified using both positive and negative ionisation modes, with potential formation mechanisms discussed. The aerosol was found to be composed primarily of polyfunctional first- and second-generation species containing one or more carbonyl, acid, alcohol and hydroperoxide functionalities, with the products significantly more complex than those proposed from basic gas-phase chemistry in the companion paper (Mackenzie-Rae et al., 2017). Mass spectra show a large number of dimeric products are also formed. Both direct scavenging evidence using formic acid and indirect evidence from double bond equivalency factors suggest the dominant oligomerisation mechanism is the bimolecular reaction of stabilised Criegee intermediates (SCIs) with non-radical ozonolysis products. Saturation vapour concentration estimates suggest monomeric species cannot explain the rapid nucleation burst of fresh aerosol observed in chamber experiments; hence, dimeric species are believed to be responsible for new particle formation, with detected first- and second-generation products driving further particle growth in the system. Ultimately, identification of the major constituents and formation pathways of α-phellandrene SOA leads to a greater understanding of the atmospheric processes and implications of monoterpene emissions and SCIs, especially around eucalypt forests where α-phellandrene is primarily emitted.

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