@article { ISI:000300887700023, title = {Competition between gelation and crystallisation of a peculiar multicomponent liquid system based on ammonium salts}, journal = {Soft Matter}, volume = {8}, number = {12}, year = {2012}, month = {FEB}, pages = {3446-3456}, publisher = {ROYAL SOC CHEMISTRY}, type = {Article}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

An exemplar competition between gelation and crystallisation phenomena was examined with an unusual synergistic multicomponent (organo) gelator solution (MGS), which consists of a well-defined methanolic solution of (1R, 2R)-1,2-diaminocyclohexane L-tartrate containing 2.4 equiv. of concentrated hydrochloric acid. The optimal composition of the MGS was determined through meticulous solubility, gelation and structural studies, which support a transient gelation mechanism based on the kinetic self-assembly of the tartrate salt driven by hydrogen-bonding interactions, involving ammonium nitrogen donors and hydroxyl oxygen acceptors, and electrostatic interactions. The hydrochloric acid is involved in the solubilisation of the salt through an ionic dissociation-exchange process, which ends up with the formation-precipitation of (1R, 2R)-1,2-diaminocyclohexane dihydrochloride. As a consequence, an irreversible destruction of the gel takes place, which indicates the metastable nature of this phase that cannot be accessed from the thermodynamically equilibrated state. Gelation of a variety of oxygenated and nitrogenated solvents with moderate polarity occurred efficiently using extremely low MGS concentrations at low temperatures, and the gel phase was confirmed by dynamic rheological measurements. Several features make the described MGS unique: (1) it is a multicomponent solution where each component and its stoichiometry play a key role in the reproducible formation and stabilization of the gels; (2) it is formed by simple, small, and commercially available chiral building blocks (dissolved in a well-defined solvent system), which are easily amenable for further modifications; (3) the gelation phenomenon takes place efficiently at low temperature upon warming up the isotropic solution, conversely to the typical gel preparation protocol; and (4) the formed organogels are not thermoreversible despite the non-covalent interactions that characterize the 3D-network.

}, issn = {1744-683X}, doi = {10.1039/c2sm07183e}, author = {Kapoor, Iti and Schoen, Eva-Maria and Bachl, Jurgen and Kuehbeck, Dennis and Cativiela, Carlos and Saha, Subhadeep and Banerjee, Rahul and Roelens, Stefano and Juan Marrero-Tellado, Jose and Diaz, David Diaz} } @article { ISI:000321004400040, title = {Crystal structure of (2S, 4R)-2-benzyl 1-tert-butyl 4-(tosyloxy)pyrrolidine-1,2-dicarboxylate, C24H29NO7S}, journal = {Zeitschrift Fur Kristallographie-New Crystal Structures}, volume = {227}, number = {3}, year = {2012}, month = {SEP}, pages = {361-362}, publisher = {OLDENBOURG VERLAG}, address = {LEKTORAT MINT, POSTFACH 80 13 60, D-81613 MUNICH, GERMANY}, abstract = {

{C24H29NO7S, triclinic, P1 (no. 1)

}, issn = {1433-7266}, doi = {10.1524/ncrs.2012.0173}, author = {Ghosh, Munmun and Mallick, Arijit and Diaz, David Diaz} } @article { ISI:000306215900022, title = {Fine-tuning the balance between crystallization and gelation and enhancement of CO2 uptake on functionalized calcium based MOFs and metallogels}, journal = {Journal of Materials Chemistry}, volume = {22}, number = {30}, year = {2012}, month = {MAY}, pages = {14951-14963}, publisher = {ROYAL SOC CHEMISTRY}, type = {Article}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

The synthesis, structure, gas adsorption and catalytic properties of a new 3D porous, crystalline metal-organic framework (Ca-5TIA-MOF) as well as stable viscoelastic metallogels (Ca-5TIA-Gel) are reported. Remarkably, the preparation of both types of materials can be carried out starting from the same organic ligand (i.e. 5-(1,2,4-triazoleyl) isophthalic acid (5TIA)), divalent metal ion (i.e. Ca(II)) and organic solvent (i.e. DMF). In this particular case, the presence of water in the solvent system favors the formation of a crystalline MOF, whereas a pure organic solvent induces gelation. The characterization of the materials was carried out using a series of techniques including XRD, FT-IR, TGA, TEM, SEM, SAXS and dynamic rheology. Experimental PXRD peaks of both Ca-5TIA-xerogel and Ca-5TIA-MOF matched reasonably well with simulated PXRD, suggesting the presence of, at least, some common structural elements in the 3D networks of both xerogel and crystalline phases. Moreover, the nature of the metal counteranion was found to have a critical influence on the gelation phenomenon. To the best of our knowledge, this report describes unprecedented Ca-based LMW-metallogels, as well as the first porous Ca-based MOF, which shows adsorption capacity for CO2 at 1 atm pressure. Interestingly, Ca-5TIA-xerogel presented 20\% higher CO2-uptake than the crystalline Ca-5TIA-MOF at 1 atm and 298 K. Both Ca-5TIA-MOF and Ca-5TIA-Gel also displayed a modest catalytic activity towards the hydrosilylation of benzaldehyde, with slightly better performance for the gel phase material.

}, issn = {0959-9428}, doi = {10.1039/c2jm30866e}, author = {Mallick, Arijit and Schoen, Eva-Maria and Panda, Tamas and Sreenivas, K. and Diaz, David Diaz and Banerjee, Rahul} } @article { ISI:000320024400001, title = {C-C Bond formation catalyzed by natural gelatin and collagen proteins}, journal = {Beilstein Journal of Organic Chemistry}, volume = {9}, year = {2013}, month = {JUN}, pages = {1111-1118}, publisher = {BEILSTEIN-INSTITUT}, address = {TRAKEHNER STRASSE 7-9, FRANKFURT AM MAIN, 60487, GERMANY}, abstract = {

The activity of gelatin and collagen proteins towards C-C bond formation via Henry (nitroaldol) reaction between aldehydes and nitroalkanes is demonstrated for the first time. Among other variables, protein source, physical state and chemical modification influence product yield and kinetics, affording the nitroaldol products in both aqueous and organic media under mild conditions. Significantly, the scale-up of the process between 4-nitrobenzaldehyde and nitromethane is successfully achieved at 1 g scale and in good yield. A comparative kinetic study with other biocatalysts shows an increase of the first-order rate constant in the order chitosan \< gelatin \< bovine serum albumin (BSA) \< collagen. The results of this study indicate that simple edible gelatin can promote C-C bond forming reactions under physiological conditions, which may have important implications from a metabolic perspective.

}, keywords = {biocatalysis, carbon-carbon bond formation, gelatin, Henry reaction, protein}, issn = {1860-5397}, doi = {10.3762/bjoc.9.123}, author = {Kuehbeck, Dennis and Dhar, Basab Bijayi and Schoen, Eva-Maria and Cativiela, Carlos and Gotor-Fernandez, Vicente and Diaz, David Diaz} } @article { ISI:000328437200053, title = {Hydrolytic conversion of a metal-organic polyhedron into a metal-organic framework}, journal = {Angewandte Chemie-International Edition}, volume = {52}, number = {51}, year = {2013}, month = {DEC}, pages = {13755-13759}, publisher = {WILEY-V C H VERLAG GMBH}, address = {BOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANY}, keywords = {cage compounds, crystal engineering, hydrophobic effect, metal-organic frameworks, Self-assembly}, issn = {1433-7851}, doi = {10.1002/anie.201307486}, author = {Mallick, Arijit and Garai, Bikash and Diaz, David Diaz and Banerjee, Rahul} } @article { ISI:000315968900025, title = {Organophotocatalysis in nanostructured soft gel materials as tunable reaction vessels: comparison with homogeneous and micellar solutions}, journal = {Journal of Materials Chemistry A}, volume = {1}, number = {14}, year = {2013}, month = {FEB}, pages = {4577-4588}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

Riboflavin tetraacetate-catalyzed aerobic photooxidation of 1-(4-methoxyphenyl)ethanol was investigated as a model reaction under blue visible light in different soft gel materials, aiming to establish their potential as reaction vessels for photochemical transformations. Three strategies involving different degrees of organization of the catalyst within the gel network were explored, and the results compared to those obtained in homogeneous and micellar solutions. In general, physical entrapment of both the catalyst and the substrate under optimized concentrations into several hydrogel matrices (including low-molecular-weight and biopolymer-based gels) allowed the photooxidation with conversions between 55 and 100\% within 120 min (TOF similar to 0.045-0.08 min(-1); k(obs) similar to 0.011-0.028 min(-1)), albeit with first-order rates ca. 1-3-fold lower than in solution under comparable non-stirred conditions. Remarkably, the organogel made of a cyclohexane-based bisamide gelator in CH3CN not only prevented the photodegradation of the catalyst but also afforded full conversion in less than 60 min (TOF similar to 0.167 min(-1); k(obs) similar to 0.073 min(-1)) without the need of additional proton transfer mediators (e. g., thiourea) as it occurs in CH3CN solutions. In general, the gelators could be recycled without detriment to their gelation ability and reaction rates. Moreover, kinetics could be fine-tuned according to the characteristics of the gel media. For instance, entangled fibrillar networks with relatively high mechanical strength were usually associated with lower reaction rates, whereas wrinkled laminated morphologies seemed to favor the reaction. In addition, the kinetics results showed in most cases a good correlation with the aeration efficiency of the gel media.

}, issn = {2050-7488}, doi = {10.1039/c3ta01109g}, author = {Bachl, Jurgen and Hohenleutner, Andreas and Dhar, Basab Bijayi and Cativiela, Carlos and Maitra, Uday and Koenig, Burkhard and Diaz, David Diaz} } @article { ISI:000321431600027, title = {Proton-conducting supramolecular metallogels from the lowest molecular weight assembler ligand: a quote for simplicity}, journal = {Chemistry-A European Journal}, volume = {19}, number = {29}, year = {2013}, month = {JUL}, pages = {9562-9568}, publisher = {WILEY-V C H VERLAG GMBH}, address = {BOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANY}, abstract = {

Oxalic acid has been proven to be the lowest molecular weight organic ligand able to form robust supramolecular metallogel networks in the presence of metal salts. In particular, two novel multifunctional metallogels were readily prepared at room temperature by simple mixing of stock solutions of Cu-II acetate monohydrate or Cu-II perchlorate hexahydrate and oxalic acid dihydrate. Formation of different polymorphs and unprecedented proton conduction under anhydrous conditions were also demonstrated with some of these materials.

}, keywords = {Copper, low-molecular-weight ligands, metallogels, proton conductivity, supramolecular chemistry}, issn = {0947-6539}, doi = {10.1002/chem.201204542}, author = {Saha, Subhadeep and Schoen, Eva-Maria and Cativiela, Carlos and Diaz, David Diaz and Banerjee, Rahul} } @article { ISI:000332027100007, title = {Amino acid-based multiresponsive low-molecular weight metallohydrogels with load-bearing and rapid self-healing abilities}, journal = {Chemical Communications}, volume = {50}, number = {23}, year = {2014}, month = {FEB}, pages = {3004-3006}, publisher = {ROYAL SOC CHEMISTRY}, type = {Article}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

A multiresponsive metallohydrogel based on an amino acid-derived low molecular weight (LMW) ligand and a Zn(II) salt was prepared. This hydrogel showed remarkable shape-persistent, self-standing, load-bearing and self-healing properties, which is uncommon in LMW hydrogels.

}, issn = {1359-7345}, author = {Saha, Subhadeep and Bachl, Jurgen and Kundu, Tanay and Diaz, David Diaz and Banerjee, Rahul} } @article { ISI:000345234900039, title = {Covalent organic framework-cadmium sulfide hybrid as a prototype photocatalyst for visible-light-driven hydrogen production}, journal = {Chemistry A-European Journal}, volume = {20}, number = {48}, year = {2014}, month = {NOV}, pages = {15961-15965}, publisher = {WILEY-V C H VERLAG GMBH}, type = {Article}, address = {BOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANY}, abstract = {

CdS nanoparticles were deposited on a highly stable, two-dimensional (2D) covalent organic framework (COF) matrix and the hybrid was tested for photocatalytic hydrogen production. The efficiency of CdS-COF hybrid was investigated by varying the COF content. On the introduction of just 1 wt\% of COF, a dramatic tenfold increase in the overall photocatalytic activity of the hybrid was observed. Among the various hybrids synthesized, that with 10 wt\% COF, named CdS-COF (90: 10), was found to exhibit a steep H2 production amounting to 3678 mmolh(-1) g(-1), which is significantly higher than that of bulk CdS particles (124 mmolh(-1)g(-1)). The presence of a p-conjugated backbone, high surface area, and occurrence of abundant 2D hetero-interface highlight the usage of COF as an effective support for stabilizing the generated photoelectrons, thereby resulting in an efficient and high photocatalytic activity.

}, keywords = {charge transfer, covalent organic frameworks, hybrid materials, hydrogen production, Photocatalysis}, issn = {0947-6539}, doi = {10.1002/chem.201403800}, author = {Thote, Jayshri and Aiyappa, Harshitha Barike and Deshpande, Aparna and Diaz, David Diaz and Kurungot, Sreekumar and Banerjee, Rahul} } @article { ISI:000337101800021, title = {Dissolvable metallohydrogels for controlled release: evidence of a kinetic supramolecular gel phase intermediate}, journal = {Chemical Communications}, volume = {50}, number = {53}, year = {2014}, month = {MAY}, pages = {7032-7035}, publisher = {ROYAL SOC CHEMISTRY}, type = {Article}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

Two metallohydrogels based on an amino acid-based ligand and Zn(II) salts were synthesized. These hydrogels show an uncommon, reversible, time-dependent transformation from the opaque to transparent state. These hydrogels also exhibit gradual dissolution in water (pH \<= 7) over time. A water-soluble stimulant, caffeine, could be in situ loaded into the hydrogels and slowly released during dissolution.

}, issn = {1359-7345}, doi = {10.1039/c4cc02771j}, author = {Saha, Subhadeep and Bachl, Jurgen and Kundu, Tanay and Diaz, David Diaz and Banerjee, Rahul} } @article {PACHFULE, title = {Highly stable covalent organic framework-Au nanoparticles hybrids for enhanced activity for nitrophenol reduction}, journal = {Chemical Communications}, volume = {50}, number = {24}, year = {2014}, month = {JAN}, pages = {3169-3172}, publisher = {ROYAL SOC CHEMISTRY}, type = {Article}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

{Gold [

}, issn = {1359-7345}, doi = {10.1039/c3cc49176e}, author = {Pachfule, Pradip and Kandambeth, Sharath and Diaz, David Diaz and Banerjee, Rahul} } @article { ISI:000341226000019, title = {Homogeneous photochemical water oxidation by biuret-modified Fe-TAML: evidence of Fe-V(O) intermediate}, journal = {Journal of the American Chemical Society}, volume = {136}, number = {35}, year = {2014}, month = {SEP}, pages = {12273-12282}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

{Water splitting, leading to hydrogen and oxygen in a process that mimics natural photosynthesis, is extremely important for devising a sustainable solar energy conversion system. Development of earth-abundant, transition metal-based catalysts that mimic the oxygen-evolving complex of photosystem II, which is involved in oxidation of water to O-2 during natural photosynthesis, represents a major challenge. Further, understanding the exact mechanism, including elucidation of the role of active metal-oxo intermediates during water oxidation (WO), is critical to the development of more efficient catalysts. Herein, we report Fe-III complexes of biuret-modified tetra-amidomacrocyclic ligands (Fe-TAML; 1a and 1b) that catalyze fast, homogeneous, photochemical WO to give OD with moderate efficiency (maximum TON = 220

}, issn = {0002-7863}, doi = {10.1021/ja503753k}, author = {Panda, Chakadola and Debgupta, Joyashish and Diaz, David Diaz and Singh, Kundan K. and Gupta, Sayam Sen and Dhar, Basab B.} } @article { ISI:000336942100020, title = {Investigation of C-C bond formation mediated by bombyx mori silk fibroin materials}, journal = {ACS Sustainable Chemistry \& Engineering}, volume = {2}, number = {6}, year = {2014}, month = {JUN}, pages = {1510-1517}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

The formation of C-C bonds is a prerequisite for all life on earth. Understanding the role of proteins in mediating the formation of these bonds is important for understanding biological mechanisms in evolution, as well as for designing {\textquoteleft}{\textquoteleft}green catalysts{\textquoteright}{\textquoteright}. In this work, the ability of silk fibroin (SF) proteins to mediate selective C-C bond formation under mild conditions was comprehensively evaluated and compared between different SF-based materials and other proteins. Aqueous SF solution (ASFS), freeze-dried SF (FDSF), mesoporous SF (MPSF), and SF hydrogel (SFHG) materials were prepared and characterized by a variety of techniques including, among others, FE-SEM, ICP-OES, FT-IR, and TGA. The nitroaldol (Henry) reaction, Knoevenagel condensation, and direct aldol reaction were used as models for this study, in which the recovery and reusability of the protein was also evaluated.

}, keywords = {Aldol-like reactions, C-C Bond formation, Knoevenagel condensation, Proteins, Silk fibroin}, issn = {2168-0485}, doi = {10.1021/sc500184r}, author = {Kuehbeck, Dennis and Ghosh, Munmun and Sen Gupta, Sayam and Diaz, David Diaz} } @article { ISI:000340469800044, title = {Mechanical downsizing of a gadolinium(iii)-based metal-organic framework for anticancer drug delivery}, journal = {Chemistry-A European Journal}, volume = {20}, number = {33}, year = {2014}, month = {AUG}, pages = {10514-10518}, publisher = {WILEY-V C H VERLAG GMBH}, address = {BOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANY}, abstract = {

A Gd-III-based porous metal-organic framework (MOF), Gd-pDBI, has been synthesized using fluorescent linker pDBI (pDBI=(1,4-bis(5-carboxy-1H-benzimidazole-2-yl)benzene)), resulting in a three-dimensional interpenetrated structure with a one-dimensional open channel (1.9x1.2nm) filled with hydrogen-bonded water assemblies. Gd-pDBI exhibits high thermal stability, porosity, excellent water stability, along with organic-solvent and mild acid and base stability with retention of crystallinity. Gd-pDBI was transformed to the nanoscale regime (ca. 140nm) by mechanical grinding to yield MG-Gd-pDBI with excellent water dispersibility (\>90min), maintaining its porosity and crystallinity. In vitro and in vivo studies on MG-Gd-pDBI revealed its low blood toxicity and highest drug loading (12wt\%) of anticancer drug doxorubicin in MOFs reported to date with pH-responsive cancer-cell-specific drug release.

}, keywords = {ball-milling, doxorubicin, drug delivery, metal-organic frameworks, nanocarriers}, issn = {0947-6539}, doi = {10.1002/chem.201402244}, author = {Kundu, Tanay and Mitra, Shouvik and Patra, Prasun and Goswami, Arunava and Diaz, David Diaz and Banerjee, Rahul} } @article { ISI:000335924100043, title = {Multifunctional and robust covalent organic framework-nanoparticle hybrids}, journal = {Journal of Materials Chemistry A}, volume = {2}, number = {21}, year = {2014}, month = {MAR}, pages = {7944-7952}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

Highly dispersed Pd(0) nanoparticles were successfully immobilized into a stable, crystalline and porous covalent organic framework (COF), TpPa-1, by a solution infiltration method using NABH(4) as a reducing agent. High resolution and dark field TEM images confirmed the uniform loading of the Pd(0) nanoparticles into the TpPa-1 matrix without aggregation. This hybrid material exhibited excellent catalytic activity towards the Cu free Sonogashira, Heck and sequential one pot Heck-Sonogashira cross-coupling reactions under basic conditions, and with superior performance compared to commercially available Pd supported on activated charcoal (i.e., 1, 5 and 10 wt\%). Additionally, the precursor Pd(II)-doped COF also displayed competitive catalytic activity for the intramolecular oxidative biaryl synthesis under acidic conditions. Both catalysts were found to be highly stable under the reaction conditions showing negligible metal leaching, non-sintering behavior, and good recyclability. To the best of our knowledge, the organic support used in this work, TpPa-1, constitutes the first COF matrix that can hold both Pd(0) nanoparticles and Pd(II) complex without aggregation for catalytic purposes under both highly acidic and basic conditions.

}, issn = {2050-7488}, doi = {10.1039/c4ta00284a}, author = {Pachfule, Pradip and Panda, Manas K. and Kandambeth, Sharath and Shivaprasad, S. M. and Diaz, David Diaz and Banerjee, Rahul} } @article { ISI:000375810400037, title = {Supramolecular metallogel that imparts self-healing properties to other gel networks}, journal = {Chemistry of Materials}, volume = {28}, number = {9}, year = {2016}, month = {MAY}, pages = {3210-3217}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

A unique proton conductive and moldable supramolecular metallogel (CuA-Ox-gel) made upon mixing at room temperature well-defined stock solutions of Cu(OAc)(2). H2O and oxalic acid dehydrate was found to have self-healing properties. Remarkably, the system also displayed an unprecedented ability to impart self-healing properties to other gel networks lacking this capacity. A self-healed CuA-Ox metallogel was found to have essentially the same nanofibrillar morphology, thermal stability, rheological properties, and conductivity as the freshly prepared sample. The discovery also allowed the fabrication of self-healing conductive composites containing conductive carbonaceous materials. Overall, this work serves as a proof of concept for the transfer of self-healing properties between completely different gel networks.

}, issn = {0897-4756}, doi = {10.1021/acs.chemmater.6b01144}, author = {Feldner, Tobias and Haering, Marleen and Saha, Subhadeep and Esquena, Jordi and Banerjee, Rahul and Diaz, David Diaz} } @article {43560, title = {Catalytic macroporous biohydrogels made of ferritin-encapsulated gold nanoparticles}, journal = {Chempluschem}, volume = {82}, year = {2017}, month = {FEB}, pages = {225-232}, abstract = {Reported is a modular approach for the incorporation and stabilization of gold nanoparticles inside a three-dimensional macroporous hydrogel made of ferritin. The strategy, which involves the dynamic templating of surfactant H-1 domains, demineralization, and remineralization helps to overcome aggregation and degradation issues usually associated with bare-metal-based nanocatalysts. The catalytic activity of the so-synthesized bionanocomposite hydrogel was demonstrated in both nitroaldol (Henry) and nitroreduction model reactions in aqueous solution at room temperature. An interesting synergistic effect between basic residues of the protein and the gold nanoparticles was found in the nitroaldol reaction when carried out in water in the presence of a phase-transfer catalyst. Furthermore, the reduction of 4-nitrophenol and 4-nitroaniline catalyzed by the nanocomposite scaffold in the presence of NaBH4 proceeded significantly faster than that using other known Au- and Ag-based catalysts under similar conditions.}, doi = {10.1002/cplu.201600454}, author = {Kumari, Sushma and Haring, Marleen and Sen Gupta, Sayam and Diaz, David Diaz} } @article {46419, title = {Biopolymer/glycopolypeptide-blended scaffolds: synthesis, characterization and cellular interactions}, journal = {Chemistry-An Asian Journal}, year = {2019}, month = {DEC}, type = {Article; Early Access}, abstract = {

Three-dimensional (3D) scaffolds formed from natural biopolymers gelatin and chitosan that are chemically modified by galactose have shown improved hepatocyte adhesion, spheroid geometry and functions of the hepatocytes. Galactose specifically binds to the hepatocytes via the asialoglycoprotein receptor (ASGPR) and an increase in galactose density further improves the hepatocyte proliferation and functions. In this work, we aimed to increase the galactose density within the biopolymeric scaffold by physically blending the biopolymers chitosan and gelatin with an amphiphlic beta-galactose polypeptide (PPO-GP). PPO-GP, is a di-block copolymer with PPO and beta-galactose polypeptide, exhibits lower critical solution temperature and is entrapped within the scaffold through hydrophobic interactions. The uniform distribution of PPO-GP within the scaffold was confirmed by fluorescence microscopy. SEM and mechanical testing of the hybrid scaffolds indicated pore size, inter connectivity and compression modulus similar to the scaffolds made from 100 \% biopolymer. The presence of the PPO-GP on the surface of the scaffold was tested monitoring the interaction of an analogous mannose containing PPO-GP scaffold and the mannose binding lectin Con-A. In vitro cell culture experiments with HepG2 cells were performed on GLN-GP and CTS-GP and their cellular response was compared with GLN and CTS scaffolds for a period of seven days. Within three days of culture the Hep G2 cells formed multicellular spheroids on GLN-GP and CTS-GP more efficiently than on the GLN and CTS scaffolds. The multicellular spheroids were also found to infiltrate more in GLN-GP and CTS-GP scaffolds and able to maintain their round morphology as observed by live/dead and SEM imaging.

}, keywords = {adhesion, Aggregates, Cellular infiltration, Spheroids}, issn = {1861-4728}, doi = {10.1002/asia.201901227}, author = {Dhaware, Vinita and Diaz, David Diaz and Sen Gupta, Sayam} } @article {48832, title = {Synthesis, characterization, crystal structure, in silico and computational studies on a novel Schiff base derived from α-chlorocinnamaldehyde and 4-aminoantipyrine}, journal = {Journal of Molecular Structure}, volume = {1289}, year = {2023}, month = {OCT}, pages = {135928}, type = {Article}, abstract = {

Schiff base, 4-(((1E,2Z)-2-chloro-3-phenylallylidene)amino)-1,5-dimethyl-2-phenyl-1,2 -dihydro-3H-pyrazol-3-one (1) was synthesized by condensation reaction of 4-aminoantipyrine and \& alpha;-chlorocinnamaldehyde. The compound was characterized using Fourier-transform infrared spectroscopy (FT-IR), ultraviolet (UV)-visible spectroscopy, proton and carbon nuclear magnetic resonance spectroscopy (1H/13C NMR) and single-crystal X-ray diffraction analysis (SC-XRD). Density functional theory (DFT) was used to compute molecular parameters and also compared them with experimental data. The X-ray diffraction data revealed that the compound crys-tallizes as a monoclinic crystal system with a space group of C2/c and Z = 8, and is stabilized by C12-H12MIDLINE HORIZONTAL ELLIPSISO1, and C8-H8AMIDLINE HORIZONTAL ELLIPSISO1 intramolecular hydrogen bonds. The presence of a distinctive azomethine C = N bond length N3-C12 of 1.283(3) \& ANGS;, and 1640 cm-1 stretching vibration in the FT-IR spectrum are evidence of the formation of a Schiff base. The computational result indicates that the ionization energy (IE), and electron affinity (EA) values for the molecule are 4.025 and 2.110 eV, respectively. The positive value of EA suggests that the addition of an electron to the molecule would be an exothermic process. The evaluated energy is relatively low and is an expression of the ease of electron transfer from the highest occupied molecular orbital (HOMO) to the lowest unoccupied molecular orbital (LUMO). Hirsfeld surface map over dnorm and curvedness surface indicated the presence of 7C-7C stacking while the shape factor index suggests donor and acceptor intermolecular C-H-7C. Analysis of Hirsfeld surfaces concerning the fingerprint indicated a minimal contribution from the de -di pair and reveals H{\textendash}H as a major contribution to the Hirsfeld surface. However, the molecular packing did not confirm H{\textendash}H as a significant contributor the packing. Docking calculations on the compound showed average theoretical binding energies toward aromatase (-5.99 \& PLUSMN; 0.34 kcal/mol) and fibroblast growth factor receptor (FGFR) (-17.57 \& PLUSMN; 6.85 kcal/mol), indicating binding interactions with both protein targets.

}, keywords = {Computational studies, molecular modeling, Schiff base, X-ray crystallography}, issn = {0022-2860}, doi = {10.1016/j.molstruc.2023.135928}, author = {Adimudo, Hillary Chijioke and Agu, Chidike Justus and Okenyeka, Obinna U. and Eddy, Nnabuk O. and Dim, Ebubechukwu Nnamdi and Dege, Necmi and Bonardd, Sebastian and Vanka, Kumar and Ibezim, Akachukwu and Idika, Digbo Iku and Diaz, David Diaz and Obasi, Nnamdi Lawrence} }