2D Bipyrimidine silver(I) nitrate: Synthesis, X-ray structure, solution chemistry and anti-microbial activit

Synthesis and X-ray single crystal structure analysis of the compound {[Ag₂(μ₂-bpym)(μ-O-NO₃)₂]}_n, (1), (where bpym = 2,2′-bipyrimidine) are presented. Compound (1) has a (6,3)-2D honeycomb structure with a tetrahedral coordination geometry around the Ag(I) ion. In contrary to the solid state structural investigation, ESI-MS for (1) in solution shows a strong peak at m/z 423.0269 which indicates that the [Ag(bpym)₂]⁺ cation is dominating instead of [Ag₂(bpym)]²⁺. The anti-microbial activity of (1) was screened against 15 multi-drug resistant bacteria in comparison to silver(I) sulphadiazine and it showed a high activity against Burkholderia mallei which causes glanders; with a MIC value of 4 μg/ml

INVESTIGATION OF BIOLOGICAL ACTIVITIES OF 4-HYDROXY-3-(2-HYDROXY-5-METHYLBENZYLIDEAMINO) BENZENESULPHONIC ACID

In this study, the antimicrobial activity, DNA cleavage, DNA binding and antioxidant properties of a sulfonic acid-based imine compound were investigated. The antimicrobial activity of the compound was investigated for minimum inhibitory concentration (MIC) against  some bacteria and yeast cultures.  The DNA cleavage activity of the compound was investigated as hydrolytic and oxidative with the gel electrophoresis method. H2O2 was used as an oxidizing agent for detection of the cleavage activity mechanism. The Ultraviolet-Visible (UV-Vis) field absorption spectroscopy method was used to determine the binding effect to DNA. The sulfonic acid-based imine compound reacted with Calf Thymus DNA (CT-DNA) which was examined by UV-Vis absorption spectroscopy. The free radical scavenging activity was determined using the 2,2-Diphenyl-1-picrylhydrazyl (DPPH) method. The studied compound was found to be effective on yeast and bacteria at different concentrations. The compound was found to be more effective on Staphylococcus aureus ATCC 25923 and Enterococcus faecalis ATCC 29212 bacteria. DNA cleavage study showed that the compound cleaved DNA without any external agents in hydrolytic and oxidative manner. UV-Vis spectroscopy studies of the interactions between the compound and CT-DNA showed that the compound interacts with CT-DNA via electrostatic binding. The compound to be tested was compared with the butylated hydroxytoluene (BHT) solution used as standard. It was found that the compound exhibits good antioxidant activity

A panchromatic, near infrared Ir(III) emitter bearing a tripodal C^N^C ligand as a dye for dye-sensitized solar cells

C.H. acknowledges the Région Bretagne, France for funding. EZ-C acknowledges the University of St Andrews and EPSRC (EP/M02105X/1) for financial support. EAG and HVF thank the ERC for a Starting Grant (p-TYPE, 715354).The synthesis of a new complex of the form [Ir(C^N^C)(N^N)Cl] [where C^N^C = 2-(bis(4-(tert-butyl)phenyl)methyl)pyridinato (dtBubnpy, L1 ) and N^N is diethyl [2,2'-bipyridine]-4,4'-dicarboxylate (deeb)] is reported. The crystal structure reveals an unusual tripodal tridentate C^N^C ligand forming three six-membered rings around the iridium center. The photophysical and electrochemical properties suggest the use of this complex as a dye in dye-sensitized solar cells. Time-Dependent Density Functional Theory (TD-DFT) calculations have been used to reveal the nature of the excited-states.PostprintPeer reviewe

Speciation of precious metal anti-cancer complexes by NMR spectroscopy

Understanding the mechanism of action of anti-cancer agents is of paramount importance for drug development. NMR spectroscopy can provide insights into the kinetics and thermodynamics of the binding of metallodrugs to biomolecules. NMR is most sensitive for highly abundant I = 1/2 nuclei with large magnetic moments. Polarization transfer can enhance NMR signals of insensitive nuclei at physiologically-relevant concentrations. This paper reviews NMR methods for speciation of precious metal anti-cancer complexes, including platinum-group and gold-based anti-cancer agents. Examples of NMR studies involving interactions with DNA and proteins in particular are highlighted

Supramolecular iridium(III) assemblies

EZ-C acknowledges the University of St Andrews for financial support and the Engineering and Physical Sciences Research Council for financial support (EP/M02105X/1)Iridium(III) complexes exhibit remarkable photophysical properties such as high photoluminescence quantum yields, wide color tunability and high chemical stability. They have featured prominently in diverse applications such as sensing, bio-imaging, photoredox catalysis, solar fuels and solid-state lighting. In the vast majority of these reports the iridium complex is mononuclear in nature. The use of iridium complexes as components of self- assembled systems has garnered increasing attention and this review aims to comprehensively document the advances made in this area. Special emphasis will be devoted to describing the photophysical properties and applications of such photo-active supramolecular materials. Soft materials such as soft salts, liquid crystals, gels, colloids incorporating iridium are described as are hydrogen bonding- and π-π staking-directed assemblies, coordination-driven self- assembled materials such as coordination polymers and metal organic frameworks, macrocycles, capsules and cages. Finally, guest Ir(III) complexes encapsulated within the cavities of cage-type structures are presented.PostprintPeer reviewe

From pyrene to large polycyclic aromatic hydrocarbons

Studies of polycyclic aromatic hydrocarbons have shown that the overall size, periphery, and functionalization of PAHs are crucial parameters which significantly alter their electronic structure and chemical reactivity. Therefore, the major direction of this thesis is the synthesis and characterization of extended PAHs: (i) with different functional groups improving their processability, (ii) with different periphery changing their chemical reactivity, (iii) with inclusions of different metal ions, which influence their physical properties. • The cyclodehydrogenation reaction has been proposed for to synthesise polyphenylene ribbons with preplanarized (dibenzo[e,l]pyrene) moieties in the aromatic core with up to 10 nm linear size. The synthetic strategy employed is discussed in Chapter 2 and is based on stoichiometrically controlled DIELS-ALDER cycloaddition. All molecules possessed very good solubility in common organic solvents allowing their characterization by standard analytical techniques. • A new concept was developed to extend PAH’s core. Here the introduction of “zigzag” sites, discussed in Chpater 3 was shown to lower the HOMO-LUMO gap and to result in higher chemical reactivities. This allowed, in Chapters 3, 4 and 5, further functionalization of PAH and enlargement of their aromatic cores up to 224 atoms. Despite the size of these novel molecules, extraordinary solubilities in common organic solvents were obtained due to distortions from planarity of the aromatic cores by bulky tert-butyl groups, which hampered the usually very pronounced aggregation tendency of extended π-systems. All extended PAHs posses the small HOMO-LUMO gap together with good electron affinities making them potential candidates for application in organic FETs. • Another alternative synthetic route has been proposed to obtain extended the metal-PAH complexes. Using the quinoxaline methodology in Chapter 5 three new phenanthroline ligands (up to 60 skeletal atoms) have been synthesized and characterized. Four different (Ru(II), Cu(II) and Pt(II)) complexes were synthesized, allowing to construct a range of large metal complexes by varying the metal as well as the number and nature of ligands