More Like this

1. Recently Developed Carbohydrate Based Gelators and Their Applications

   https://doi.org/10.3390/gels7010024  

   Morris, Joedian; Bietsch, Jonathan; Bashaw, Kristen; Wang, Guijun (March 2021, Gels)

   null (Ed.)

   Carbohydrate based low molecular weight gelators have been an intense subject of study over the past decade. The self-assembling systems built from natural products have high significance as biocompatible materials and renewable resources. The versatile structures available from naturally existing monosaccharides have enriched the molecular libraries that can be used for the construction of gelators. The bottom-up strategy in designing low molecular weight gelators (LMWGs) for a variety of applications has been adopted by many researchers. Rational design, along with some serendipitous discoveries, has resulted in multiple classes of molecular gelators. This review covers the literature from 2017–2020 on monosaccharide based gelators, including common hexoses, pentoses, along with some disaccharides and their derivatives. The structure-based design and structure to gelation property relationships are reviewed first, followed by stimuli-responsive gelators. The last section focuses on the applications of the sugar based gelators, including their utilization in environmental remediation, ion sensing, catalysis, drug delivery and 3D-printing. We will also review the available LMWGs and their structure correlations to the desired properties for different applications. This review aims at elucidating the design principles and structural features that are pertinent to various applications and hope to provide certain guidelines for researchers that are working at the interface of chemistry, biochemistry, and materials science. 

   more » « less
2. Syntheses, Structural Studies, and Copper Iodide Complexes of Macrocycles Derived from Williamson Ether Syntheses Involving 2,9-Bis(4-hydroxyphenyl)-1,10-phenanthroline, α,ω-Dibromides, and Resorcinol or 2,7-Dihydroxynaphthalene

   https://doi.org/10.1071/CH16587  

   Baranová, Zuzana; Amini, Hashem; Neupane, Madhav; Garrett, Sydney C.; Ehnbom, Andreas; Bhuvanesh, Nattamai; Reibenspies, Joseph H.; Gladysz, John A. (January 2017, Australian Journal of Chemistry)

   1,3-Bis(6-bromohexyloxy)benzene, 2,7-bis(6-bromohexyloxy)naphthalene, 1,3-bis(4-bromomethylbenzyloxy)benzene, and 1,3-bis(3-bromomethylbenzyloxy)benzene were prepared via Williamson ether synthesis using resorcinol or 2,7-dihydroxynaphthalene and 1,6-dibromohexane, 1,4-bis(bromomethyl)benzene, or 1,3-bis(bromomethyl)benzene (21–47 % yield). These dibromides were condensed with 2,9-bis(4-hydroxyphenyl)-1,10-phenanthroline in the presence of K2CO3 to give the corresponding 31- to 35-membered macrocycles (3a–d, 22–63 % yield). When 3a–d were treated with CuI, mononuclear 1 : 1 complexes formed, in which the CuI chelates to the nitrogen donor atoms of the phenanthroline moiety (4a–d, 40–80 % yield). The crystal structures of 3a–c and 4a–c were determined and analyzed using density functional theory calculations and in the context of rotaxanes that could be formed by treatment of 4a–d with terminal alkynes (e.g. macrocycle dimensions, void volumes). The copper and iodide atoms in 4a–c significantly protrude from the least-squares plane of the phenanthroline moiety (0.46–0.63 Å and 1.65–2.07 Å). 

   more » « less
3. Synthesis of Carbohydrate Based Macrolactones and Their Applications as Receptors for Ion Recognition and Catalysis

   https://doi.org/10.3390/molecules26113394  

   Adhikari, Surya B.; Chen, Anji; Wang, Guijun (June 2021, Molecules)

   null (Ed.)

   Glycomacrolactones exhibit many interesting biological properties, and they are also important in molecular recognitions and for supramolecular chemistry. Therefore, it is important to be able to access glycomacrocycles with different sizes and functionality. A new series of carbohydrate-based macrocycles containing triazole and lactone moieties have been designed and synthesized. The synthesis features an intramolecular nucleophilic substitution reaction for the macrocyclization step. In this article, the effect of some common sulfonate leaving groups is evaluated for macrolactonization. Using tosylate gave good selectivity for monolactonization products with good yields. Fourteen different macrocycles have been synthesized and characterized, of which eleven macrocycles are from cyclization of the C1 to C6 positions of N-acetyl D-glucosamine derivatives and three others from C2 to C6 cyclization of functionalized D-glucosamine derivatives. These novel macrolactones have unique structures and demonstrate interesting anion binding properties, especially for chloride. The macrocycles containing two triazoles form complexes with copper sulfate, and they are effective ligands for copper sulfate mediated azide-alkyne cycloaddition reactions (CuAAC). In addition, several macrocycles show some selectivity for different alkynes. 

   more » « less
4. Inclusion Polymerization of Pyrrole and Ethylenedioxythiophene in Assembled Triphenylamine Bis -Urea Macrocycles

   https://doi.org/10.1021/acs.macromol.2c02042  

   Islam, Md Faizul; Adame-Ramirez, Emely; Williams, Eric R.; Kittikhunnatham, Preecha; Wijesekera, Andrew; Zhang, Siteng; Ge, Ting; Stefik, Morgan; Smith, Mark D.; Pellechia, Perry J.; et al (December 2022, Macromolecules)
5. Copper-Cross-Linked Alginate-Based Hydrogel Nanoparticles for Sustainable Slow-Release Fertilizer Applications

   https://doi.org/10.1021/acs.langmuir.5c00910  

   Jalomo, Catherine A; Schroeder, Adriana G; Hernandez, Ehmely M; Murphy, Catherine J (July 2025, Langmuir)

   Controlled-release materials are desirable for many delivery applications and have been used to improve the efficiency of fertilizers and pesticides in crop management. Due to their potential to reduce application of toxic chemicals while prolonging exposure to active agents, controlled-release nanomaterials are currently being investigated for increasing agricultural production and preventing overfertilization. Hydrogels are underexplored as controlled-release nanomaterials and can deliver many types of cargo, from metal ions to small molecules. Alginate-based hydrogels are biocompatible and their internal carboxylic acids coordinate agriculturally valuable micronutrients like Cu2+, Zn2+, and Ca2+. Hydrogels comprising ionic and nonionic polymers can coordinate agriculturally valuable micronutrients, and the combination of ionic and nonionic polymers results in hydrogels with tunable release profiles. Alginate, for example, contains carboxylates that ionically cross-link with divalent cations like Cu2+, Zn2+, and Ca2+, while polar moieties on chitin enable nonionic coordination. To our knowledge, soft-material copper-loaded nanoparticles have not yet been applied as controlled-release materials for foliar delivery. In this work, we present the synthesis and micronutrient release characteristics of hydrogel nanoparticles containing Cu2+, which is coordinated by ionic and nonionic polymers. Hydrogel nanoparticles (HNPs) were prepared by liquid–liquid emulsion techniques and cross-linked with Cu2+ to form double-network hydrogels made from alginate and non-cross-linking chitin. Nanoparticles (100–300 nm in diameter) were characterized by cryogenic electron microscopy, nanoparticle tracking analysis, Fourier transform infrared spectroscopy, and thermogravimetric analysis. The copper release profiles of HNPs with different polymer compositions were compared. HNPs containing both chitin and alginate released 8–20 times more copper than HNPs with alginate alone, suggesting that the presence of non-cross-linking polymers improves copper release. Thus, HNP delivery characteristics can be tuned by manipulating intraparticle bond dynamics in the hydrogel polymer matrix. 

   more » « less