Volume 85, Issue 2

It is a privilege to act as the conference editor for this issue of Pure and Applied Chemistry ( PAC ) dedicated to the 12th Eurasia Conference on Chemical Sciences (EuAsC 2 S-12). The Eurasia Conferences on Chemical Sciences started in Bangkok in 1988 under the leadership of the founders, Bernd M. Rode (Austria), Hitoshi Ohtaki (Japan), and Ivano Bertini (Italy), together with Salag Dhabandana (Bangkok). During the preparation of the present issue of PAC , on 7 July 2012, Ivano Bertini, leading scientist in chemistry and biology, passed away. We will always remember him for his unselfish leadership and enormous contribution in paramagnetic NMR. The aim of the conferences is to foster friendship and exchange of knowledge between chemists in the Eurasian supercontinent as well as those in the Americas and Australia. While all previous conferences have been held in Asia or the Middle East, EuAsC 2 S-12 took place at the Hotel Corfu Chandris, on the island of Corfu, Greece, on 16-21 April 2012 with the aim of encouraging and enhancing the participation of European scientists and thus help to make them better known. EuAsC 2 S-12 was organized by the University of Ioannina on the Greek mainland with Emeritus Prof. Nick Hadjiliadis as Chair of the local organizing committee. The total number of participants was 450, with ca. 400 active delegates from 60 countries. The scientific program comprised 14 sessions, each of which was represented by invited speakers and further oral presentations on the following topics: - bioinorganic chemistry - pharmaceutical chemistry and drug design - organic synthesis and natural products - environmental and green chemistry - physical chemistry and spectroscopy - theoretical and computational chemistry - organometallic chemistry and catalysis - clinical biochemistry and molecular diagnostics - coordination chemistry and inorganic polymers - analytical and solution chemistry - supramolecular chemistry and nanomaterials - food chemistry - chemical education - polymer science The scientific program, which was accompanied by a rich social activities program, included 9 plenary lectures, 214 oral presentations, and 190 poster presentations. The collection of 13 papers in this issue of PAC is a representation of the topics related to inorganic chemistry, covered in the lectures held during EuAsC 2 S-12. The papers represent a good cross-section of major themes ranging from traditional coordination chemistry, bio inorganic chemistry, supramolecular coordination chemistry, catalysis, and inorganic materials. The 13th Eurasia conference will be held in India in December 2014 with Prof. N. Jayaraman, Bangalore as head of the organizing committee. John C. Plakatouras Conference Editor

The importance of 3d/4f-metal cluster chemistry is outlined, and the employment of 2-pyridyl ketone- and 2-pyridyl oxime-based ligands for the preparation of low-nuclearity Ni II /Ln III complexes (Ln = lanthanide) is reviewed. The synthetic utility of the “metal complexes as ligands” and “one-pot” approaches is critically discussed. The small nuclearity of the products permits the in-depth analysis of their magnetic properties.

Reaction of KVO 3 with 2-[ N , N '-(carboxymethyl)aminomethyl]-5-methylhydroquinone (H 4 mecah) in aqueous solution at pH 8.2 results in the isolation of mononuclear K 2 [V V (O) 2 {Hmecah(-3)}]·2H 2 O complex. On the other hand, reaction with the 2-[ N , N '-(carboxymethyl)aminomethyl]-5- tert- butylhydroquinone (H 4 t butcah) under the same conditions gives the tetranuclear mixed-valent complex K 6 [{V V O( μ -O)V IV O}{ μ - t butbicah(-6)}] 2 ·10.5H 2 O (H 6 t butbicah, 2,2'-({2-[bis(carboxymethyl)amino]-3,6-dihydroxy-4-methylbenzyl}azanediyl)diacetic acid). The structures of both complexes were determined by single-crystal X-ray crystallography. The coordination environment of vanadium ions in both complexes is octahedral, with four out of the six positions to be occupied by the two cis carboxylate oxygens, one hydroquinonate oxygen, and one amine nitrogen atoms of the ligands’ tripod binding sites. The importance of the chelate ring strains in the stabilization of the p -semiquinone radical is also discussed. A protonation of the ligated to vanadium(IV) ion hydroquinonate oxygen at low pH was revealed by continuous wave (cw) X-band electron paramagnetic resonance (EPR) and UV–vis spectroscopies.

In an effort to design dinuclear Pt II compounds that maintain the target (DNA) binding profile of the trans -oriented dinuclear bifunctional Pt II complexes containing aliphatic linker chains but are less susceptible to metabolic decomposition, the new, long-chain dinuclear Pt II complexes—[{ trans -PtCl(dien)} 2 -μ-(CH 2 ) n ] 2+ ( n = 7,10,12, dien = diethylenetriamine)—were synthesized. The toxicity of these metallodrugs was examined in ovarian tumor cell lines. The results showed that the activity of these complexes increased with growing length of the linker; the activity of complex containing the longest linker ( n = 12) was comparable with that of cis -diamminedichloridoplatinum(II) (cisplatin). This observation correlated with the results of DNA binding studies performed in cell-free media. The results of these studies demonstrated that the growing length of the aliphatic bridge promoted more distorting conformational alterations induced in DNA. Attention was also paid to the reactivity of {[Pt(dien)Cl] 2 -alkane} compounds with glutathione (GSH). The results of these experiments support the thesis that the dinuclear structure of {[Pt(dien)Cl] 2 -alkane} complexes remains stable in the presence of S-containing compounds without undergoing chemical degradation as previously observed for some di/trinuclear bifunctional Pt II complexes. This enhanced stability represents a favorable property which may contribute to reduce side effects and increase therapeutic efficacy of the dinuclear {[Pt(dien)Cl] 2 -alkane} compounds.

The products obtained by forcing the reaction with nucleosides (guanosine, Guo, and adenosine, Ado) of potential anticancer drugs for nongenomic targets [PtCl( O , O' -acac)(L)] (L = dimethyl sulfoxide, DMSO; dimethyl sulfide, DMS), closely related to their very powerful organometallic analogues [Pt( O , O' -acac)(γ-acac)(L)], have been studied. [PtCl( O , O' -acac)(L)] and [Pt( O , O' -acac)(γ-acac)(L)] complexes were reported unreactive toward nucleobases. Aquo species [Pt( O , O' -acac)H 2 O(L)] + , obtained from [PtCl( O , O' -acac)(L)] by Ag + driven coordinated Cl – removal, gave access to [Pt( O , O' -acac)(L)(nucleoside)] + ([Pt( O , O' -acac)(DMSO)(Guo)] + , [Pt( O , O' -acac)(DMS)(Guo)] + , [Pt( O , O' -acac)(DMSO)(Ado)] + ). The effect of the chelate oxygen donor acac (with respect to a chelate diammine), the role of the sulfur ligand (DMSO, DMS), and the influence of the purinic nucleoside itself on the coordinated Guo or Ado dynamic motions in [Pt( O , O' -acac)(L)(nucleoside)] + complexes have been investigated by NMR spectroscopy. Interestingly, a slow rotation of nucleobase around the Pt–N(7) bond with formation of two rotamers was observed already at room temperature only in the case of [Pt( O , O' -acac)(DMSO)(Guo)] + . On the other hand, no hindered rotation at room temperature was detected in the analogous [Pt( O , O' -acac)(DMS)(Guo)] + and [Pt( O , O' -acac)(DMSO)(Ado)] + complexes. Data suggest that rotation of the nucleoside in [Pt( O , O' -acac)(L)(nucleoside)] + is very different with respect to the analogous [Pt(diammine)(L)(nucleoside)] 2+ systems, due to specific interactions between the acac chelate ligand, the DMSO, and the nucleobase.

The metal coordination complexes are known to induce cytotoxic effects on various cell lines and shown to have great potential for therapeutic interventions. Their main mechanism of action is through the mediation of enzyme activities in signaling pathways essential for cellular functioning. The overall cellular responses are dose-dependent and require high exposure levels and duration to overcome cellular defense against external toxicants. However, their effect through signal transduction components is limited due to the conferred drug resistance associated with glutathione transferase (GST)-mediated mechanisms. The GST family of enzymes is not only related to anticancer drug resistance, but also associated with cancer development where they may also contribute kinase signaling events including non-receptor protein tyrosine kinase (PTK)-related pathways. In the current study, we evaluated the effect of symmetrical and mononuclear complexes of Pd(II), Pt(II), and Ni(II) with organic ligands on cytosolic targets involved in glutathione utilization, antioxidant defense, and kinase signaling by virtue of acellular in vitro analyses.

Multicomponent coupling reactions provide a method to combine several substrates in a single reaction. When coupled with transition-metal catalysis, these reactions can be used to both activate and control the assembly of multiple simple building blocks directly into useful products. This account will describe our work in this area, with a focus on the use of palladium catalysis as a tool to couple imines and CO with other substrates into a range of heterocyclic derivatives in one-step reactions.

In this article, a brief review of the recent functionalizations of the cage-like water-soluble phosphine 1,3,5-triaza-7-phosphaadamantane (PTA), involving N -quaternization (lower rim) and introduction of a side arm in C-6 position (upper rim) will be presented, highlighting selected examples in their use as ligands for ruthenium(II), iridium(I), and rhodium(I) moieties together with applications of the related complexes in homogeneous catalysis.

With the current advances in our understanding of molecular components in the solid-state world, the relation between energy and geometry remains controversial. In this study, we deliver a concise account for supramolecular chemistry, and in order to illustrate some of its concepts we describe some structural and theoretical analyses for two unique cases of our work. We elaborate on a supramolecular model of controlled “one-pot” host–guest metal-mediated self-assembly reaction inside iron coordination polymer grid architecture, and we review halogen bonding by specifically observing M–Cl···Cl–M intermolecular interactions using Cambridge Structural Database (CSD) hit analyses with theoretical calculations.

While isotropic metal–carboxylate clusters as secondary building blocks have enabled the rational design of porous coordination polymers (PCPs) with predictable topologies, augmented metal–carboxylate–pyridyl clusters can be used as anisotropic secondary building blocks to facilitate the construction of higher-connectivity frameworks and control over structural directionality in self-assembly.

Single-crystalline anatase TiO 2 nanorods (TiO 2 -SANRs) were synthesized through a facile solvothermal method and successfully applied as the photoanodes for efficient dye-sensitized solar cells (DSCs). The prepared samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). The power conversion efficiencies of TiO 2 -SANRs decorated Degussa P25 nanoparticle solar cells increased by 13.5 % compared with commercial Degussa P25 TiO 2 solar cells under standard illumination conditions (AM 1.5G, 100 mW/cm –2 ). The improved performance of the TiO 2 -SANRs decorated Degussa P25 nanoparticle solar cells was primarily ascribed to the enhanced short-circuit photocurrent density ( J sc ) despite a declined dye-loading capacity. The light-scattering effect in the long-wavelength region, as evidenced from the incident photon-to-current conversion efficiency (IPCE) response and the diffuse reflectance spectroscopy was recognized as the main reason for the photocurrent enrichment.

The change of the primary energy source from fossil fuels to the so-called renewable energies, such as solar and wind energy, is a major and necessary trend. The use of these energies needs efficient methods of energy storing and restoring, and hydrogen can serve for an effective conversion between the electricity and the chemical energy. This paper describes the ion-conducting materials applicable to the so-called “hydrogen energy system”. Since hydrogen works as an energy medium in this system, hydrogen-ion-transporting materials are beneficial. Proton-conducting oxides will work for this purpose and will be introduced here, viewing from material designing and working mechanism. Application of the proton-conducting oxide materials to water electrolysis is another topic, and how the materials work in principle for conversion between electricity and chemical energy and how their performances could/can be improved will be described.

Energy has emerged as a strategic priority not only in research but also in all aspects of human lives. Most worldwide problems could be solved if energy were plentiful. In order to solve the energy problem, the following methods could be applicable: the creation of electricity from renewable energy resources, increase in conversion efficiency from fossil fuels to electricity, recovery of electricity from exhaust heat energy, and reduction of energy consumption. Nanotechnologies have already shown good promise in addressing and offering solutions in these priority areas. Here, we have demonstrated the application of metal nanoparticles (NPs) to electrocatalysts for the polyelectrolyte fuel cell (increase in conversion efficiency) and to additives to form hybrids with organic thermoelectric materials of conducting polymers (recovery of energy from exhaust heat). Thus, Pt monometallic and AuPt bimetallic NPs were used for electrocatalysts with high performance, and Pt and Au NPs were applied to hybrid thermoelectric materials to fabricate hybrid films with increasing thermoelectric performance for conversion of the exhaust heat near room temperature.

In the present study, the impact of sintering temperature on the phase composition and antibacterial properties of silver-doped hydroxyapatite (HAp/Ag) samples was investigated. HAp/Ag containing 0.2 and 1.2 % silver was prepared using a modified wet chemical precipitation method. The surface morphology and inner structure of the sintered samples were discussed. X-ray powder diffraction (XRD) and scanning electron microscopy (SEM) studies showed that, after the sintering process, HAp/Ag contained a silver oxide phase, which was not observed in raw materials. Phase composition changes at different sintering temperatures were studied, and it was found that silver oxide undergoes phase changes during the sintering process. In vitro antibacterial properties approved the excellent antimicrobial activity of HAp/Ag against the bacterial strains Staphylococcus epidermidis and Pseudomonas aeruginosa . The HAp/Ag sample with 1.2 % silver content, sintered at 1150 °C, showed the highest antibacterial activity.

In the past, aggregation and self-assembly have been associated principally with micellar and colloidal systems of molecules; however, with the advent of supramolecular chemistry, molecular self-assembly has been opened to a much wider understanding that has facilitated access to a variety of different shapes and sizes, along with the construction of new and fascinating molecular topologies. This document aims at defining more than 150 terms related to aggregation and self-assembly in the particular case of macromolecules. The list is restricted to the most commonly encountered terms.