Synthesis, Structural Analysis and Antibacterial Effect of a Novel Heteronuclear-Coordination Polymer

The crystal complex was crystallised the triclinic space group. The smallest repeating unit of the complex contains an [Fe(TPT)Ag2(H2O)2](ClO4)3 unit. The Fe atom is coordinated by three nitrogen of terpyridine moiety from one TPT ligand and by three nitrogen of terpyridine moiety from another TPT ligand in an octahedral geometry fashion. While one Ag atom is coordinated by two nitrogen atoms of one pyrazolyl moiety from a TPT ligand and two nitrogen atoms of adjacent pyrazolyl moiety from another TPT ligand to generate a linear coordination polymer in a tetragedral geometry. The third nitrogen atom of the last pyrazolyl part is also coordinated to a silver ion which was itself coordinated to two water molecules through their oxygen atoms in a trigonal planar geometry. In vitro study of the complex against some bacterial pathogens were also investigated.

The synthesis and crystal structure of a novel polymeric silver(I)-Iron(II) complex containing bridging ligand 4’-(4-(2,2,2-tris(1H-pyrazol-1-ido)ethoxymethyl)phenyl-2,2’:6’,2”-terpyridine (TPT) are described. The reaction of TPT with FeCl2.6H2O afforded a complex [Fe(TPT)2]Cl2 which in turn reacted with a range of silver salts such as AgNO3, AgClO4 resulted in the formation of heterometal complexes which were characterised using 1H NMR and ES-MS techniques. The reaction solution of the [Fe(TPT)2]Cl2 complex with molar eqiuvalnet of AgClO4 resulted in a solution with gace needdle-like crystals suitable for single X-ray crystallography.

There has been extensive studies of binding of chiral Ru(II) complexes to DNA backbone structures. J. K. Barton has studies the cationic coordination of a variety of chiral poly-pyridine Ru(II) complexes to demonstrate chiral discrimination in binding to different forms of DNA. Many experimental techniques have been applied to study the interaction of tris(phenanthroline)ruthenium(II) with DNA, but despite this, its binding mode and its effect on the DNA structure are uncertain and have been the subject of much controversy. In this study, bis[4'-(4-methylphenyl)-2,2':6',2"-terpyridine]Co(III) tris(nitrate) complex was synthesized and characterized using conventional method such as 1H NMR, ES-MS, UV-vis spectrophotometry. The Co ion was six coordinated, but the geometry was significantly distorted from that of an ideal octahedral. In this study, the terpyridine type ligand fragment appealed because the ligand structure ensures a meridional arrangement of the donor atoms, which reduces the number of possible isomers. Co(III) ion was attracted because of its higher positive charge compared to Ru(II) which will have more affinity towards the negatively charged DNA structure.

Absorbance and fluorescence methods, and circular dichroism, were used to study the interaction of the Co(III) complex solution in water with DNA.

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Program Manager | Crystallography Congress 2018

Email: crystallography@enggmeeet.com

Advanced Materials for Protein Crystallization

The crystallization of proteins, nucleic acids, biological complexes, will depend on the creation of a solution that is supersaturated in the macro molecule. Since 60 years, X-ray crystallography provides structural details of protein molecules, information that is crucial to unravel biological mechanisms at molecular level. Crystallography requires that sample is in crystal form. Getting such crystals at acceptable quality for crystallographic analysis is not trivial and strategies to make this process less expensive and time consuming are not available, still now.

Technologies that assist with Protein crystallization

·         High throughput crystallization screening

·         Protein engineering

Advanced materials represent a turning point in this field because they can be exploited to control nucleation and growth step making more effective the crystallization process. Researchers are developing membrane-based materials able to trigger protein crystallization also in conditions that are not fruitful by standard methods.  Such materials have a great impact both in industry and academic studies because significantly reduce cost and time of the protein purification and crystallization process. Then they developed membrane-materials functionalized by hydro-gel that proved ability in getting very stress-resistant crystals, which are suitable for structure-based drug design studies that require very harsh soaking conditions. This material, similarly to our metal oxide nano particle-functionalized membrane, significantly widens crystallization window and produce crystals having good diffraction quality. 

Methods of protein crystallization

·         Vapor diffusion

·         Micro batch

·         Micro-dialysis

·         Free-interface diffusion

Membrane based materials are showing very effective in protein crystallization and to produce crystals having specific features. Our efforts are focusing now in functionalizing such materials by Nano template to crystallize very challenging proteins such as intact antibodies, and to develop membrane able to promote bio mineralization and to enable poly-morphs selection. 

Attend our upcoming conference “4th International Conference on Crystallography & Novel Materials”, during November 19-20, 2018 at Bucharest, Romania and share your knowledge and latest updates regarding smart materials and material science.

Contact:

Jessica Mark

Program Manager | Crystallography Congress 2018

Mail us:  crystallography@enggmeet.com