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Yields of a rotaxane can be improved by employing a two-step capture protocol. Cooling a solution of the linear and macrocyclic components required for the rotaxane increases the population of the target pseudorotaxane, which is then captured by a rapid capping reaction between an azide and PPh(3). The resulting iminophosphorane rotaxane can then be manipulated synthetically at elevated temperatures.

A tri-enzyme system consisting of choline kinase/choline oxidase/horseradish peroxidase was used in the rapid and specific determination of the biomarker for bacterial sepsis infection, secretory phospholipase Group 2-IIA (sPLA2-IIA). These enzymes were individually immobilized onto the acrylic microspheres via succinimide groups for the preparation of an electrochemical biosensor. The reaction of sPLA2-IIA with its substrate initiated a cascading enzymatic reaction in the tri-enzyme system that led to the final production of hydrogen peroxide, which presence was indicated by the redox characteristics of potassium ferricyanide, K3Fe(CN)6. An amperometric biosensor based on enzyme conjugated acrylic microspheres and gold nanoparticles composite coated onto a carbon-paste screen printed electrode (SPE) was fabricated and the current measurement was performed at a low potential of 0.20 V. This enzymatic biosensor gave a linear range 0.01–100 ng/mL (R2 = 0.98304) with a detection limit recorded at 5 × 10−3 ng/mL towards sPLA2-IIA. Moreover, the biosensor showed good reproducibility (relative standard deviation (RSD) of 3.04% (n = 5). The biosensor response was reliable up to 25 days of storage at 4 °C. Analysis of human serum samples for sPLA2-IIA indicated that the biosensor has potential for rapid bacterial sepsis diagnosis in hospital emergency department.

The tetradentate ligand with four donor atoms OONN was synthesized. Bis(phenoxy)bipyridine ligand was prepared by Suzuki coupling reaction between 6,6’-dibromo-2,2’-bipyridyl and 2-hydroxyphenylboronic acid with presence of palladium (II) acetate. Bis(phenoxy)bipyridine ligand was also synthesized by demethylating of 6,6’-bis(2-methoxyphenyl)-2,2’-bipyridyl ligand through solvent free reaction using pyridine hydrocloride. The formation of both phenoxy and methoxy ligands was confirmed by 1H, 2D cosy and 13C NMR spectroscopy, ESI-MS spectrometry, FTIR spectroscopy. The purity of the ligand was confirmed by melting point. Binding studies of small molecules with DNA are useful to understand the reaction mechanism and to provide guidance for the application and design of new and more efficient drugs targeted to DNA. In this study, the binding interaction between the synthesized ligand with calf thymus-DNA (ct-DNA) has been investigated by UV/Vis DNA titration study. From the UV/Vis DNA study, it shows that bis(phenoxy)bipyridine ligand bind with ct-DNA via outside binding with binding contant Kb = 1.19 × 103 ± 0.08 M−1.

Synthesis of imine compounds usually results in moderate yield due its reversibility characteristic and prone to hydrolysis. Hence, to increase the formation of imine compound, self-replicating catalyst was introduced. The self-replicating catalyst is the imine product itself. The first imine compound, 4-{[4-(3,5-Dimethyl-phenylcarbamoyl)-benzylidene]-amino}-phenyl)-acetic acid has been synthesized from 4-Amino-N-(3,5-dimethyl-phenyl)-benzamide and (4-formyl-phenyl)-acetic acid. Simultaneously, 4-formylbenzoic acid was reacted with thionyl chloride to produce 4-formylbenzoyl chloride, which was then reacted with 2-amino-4,6-dimethylpyridine in the presence of triethylamine to afford N-(4,6-dimethyl-pyridin-2-yl)-4-formyl-benzamide. N-(4,6-dimethyl-pyridin-2-yl)-4-formyl-benzamide formed then reacted with 4-amino-2-methylbenzoic acid to form the second imine derivative, 4-{[4-(4,6-dimethyl-pyridin-2-ylcarbamoyl)-benzylidene]-amino}-2-methyl-benzoic acid. The concentration time profile for the synthesis of self-replicating imine 1 reveals the classic sigmoidal shape characteristics of an autocatalytic process and the rate of the reaction are higher than that observed in the absence of recognition. In order to demonstrate the nature of self-replicating catalyst, a preformed imine 1 was doped into the reaction mixture of amine 1 and the corresponding aldehyde, 4-formylbenzoic acid. The insertion of substoichiometric amounts (15 mol%) of imine 1 at the start of the reaction has accelerated the rate formation of imine 1.

A novel symmetrical macrocycle has been synthesised via oxidative homocoupling of bisalkyne, diprop-2-ynyl pyridine-2,6-dicarboxylate mediated by copper (I) iodide (CuI) and 4-dimethylaminopyridine (DMAP). The precursor compound was synthesised from 2,6-pyridine dicarbonyl dichloride and propargyl alcohol in the presence of triethylamine. The reaction mixture was stirred overnight and further purified via column chromatograpy with 76% yield. Single crystal for X-ray study was obtained by recrystallization from acetone. Subsequently, a symmetrical macrocycle was synthesised from oxidative homocoupling of precursor compound in open atmosphere. The crude product was purified by column chromatography to furnish macrocycle compound with 5% yield. Both compounds were characterised by IR, 1H and 13C NMR and mass spectral techniques. The unusual conformation of the bisalkyne and twisted conformation of designed macrocycle has influence the percentage yield. This has been studied thoroughly by X-ray crystallograph...

The complete title molecule, C23H19N3O2, is generated by a twofold axis passing through the central ring. The two oxymethylbenzonitrile arms are attached at themetapositions of the central pyridine ring. The dihedral angle between the pyridine ring and benzene ring of both arms is 84.55 (6)° while the benzene rings make a dihedral angle of 46.07 (7)°. In the crystal, weak C—H...π interactions link the molecules sheets parallel to theacplane.