Volume 86, Issue 6

Synthesis of novel solids, in a chemical sense, is one of the spearheads of innovation in materials research. However, such an undertaking is substantially impaired by lack of control and predictability. We present a concept that points the way towards rational planning of syntheses in solid state and materials chemistry. The foundation of our approach is the representation of the whole material world, i.e., the known and not-yet-known chemical compounds, on an energy landscape, which implies information about the free energies of these configurations. From this it follows at once that all chemical compounds capable of existence (both thermodynamically stable and metastable ones) are already present in virtuo in this landscape. For the first step of synthesis planning, i.e., the identification of candidates that are capable of existence, we computationally search the respective potential energy landscapes for (meta)stable structure candidates. Recently we have extended our techniques to finite temperatures and pressures and calculated phase diagrams, including metastable manifestations of matter, without resorting to any experimental pre-information. The conception developed is physically consistent, and its feasibility has been proven. Applying appropriate experimental tools has enabled us to realize, e.g., elusive Na 3 N, including almost all of its predicted polymorphs, many years after the predictions were published.

Photodynamic therapy (PDT), especially with the recent advances in photosensitizer (PS) design, has already been established as a noninvasive technique for cancer treatment. Recently, near-IR-based absorbing PSs that have a rising potency to implement light-triggered tumor ablation have attracted much attention since near-IR light in the 650–850 nm range penetrates more deeply in tissues. Up to now, numerous nanomaterials tailored to suitable sizes have been studied for effective delivery of PSs. In this study, four different types of Bodipy-based PSs were covalently attached to magnetic resonance imaging (MRI) active, biocompatible, and nontoxic nanocarriers and generation of singlet oxygen capabilities were evaluated. It was demonstrated that these core-shell nanoparticles are promising delivery vehicles of PSs for use in diagnosis and therapy.

Glycerol acetals were prepared from glycerol and aromatic aldehydes (benzaldehyde, anisaldehyde, or furfural) using a solid acid (Amberlyst-15) catalyst. The acetals show promising antioxidant activity using the DPPH test with the glycerol/anisaldehyde acetal showing the best antioxidant properties, attributed to the additional radical stabilization by the electron-releasing methoxy group. The acetals formed have a wide range of potential industrial applications particularly enabling integration of the biodiesel manufacturing chain.

This paper focuses on α-lithiated oxazolinyloxiranes and oxazolinylaziridines, their generation, reactions, and synthetic applications. The ability of the oxazoline ring in providing stabilization to such α-heterosubstituted carbanions either through electronic effects and coordinative action has been stressed as well as the contribution to the configurational stability or instability of such species. IR spectroscopic data, multinuclear NMR investigations, and ab initio calculations planned to get insights on chemical properties and structural features have been carried out. A number of new reactions including alkylations, addition reactions, hydroxyalkylations, cyclopropanations, lactonizations, and rearrangements have been discovered, giving access to a variety of substances including: aziridinolactones, epoxylactones, aryl alkanones, polysubstituted cyclopropanes, cyclopropanefused lactones, dihydro-oxazoloisoquinolines, diversely functionalized oxazolines, and products that can be derived from them by synthetic elaboration.

A series of metal triflate-catalyzed addition reactions of pyrrole to C=C and C=N bonds have been investigated to access pyrrole-based heterocyclic compounds. The addition of pyrrole to different α,β-unsaturated compounds or N -tosyl imines afforded suitable structures for the construction of [5-5] bicyclic systems or porphyrins, respectively. Intramolecular cyclization reactions were applied for the synthesis of pyrrolizine derivatives. In the other reaction mode, intermolecular cyclization reactions gave A 4 - and trans -A 2 B 2 - meso -substituted porphyrins under mild reaction conditions with low scrambling.

This paper focuses on recent advances in the chemistry of bifunctional Ru catalysts with chelate protic amine ligands effective for hydrogenation of polar carbonyl compounds. The rational design of the cooperating amine ligand that adjusts the balance of the electronic factors on the M/NH units in the bifunctional catalysts is crucial to exploit the characteristic catalytic performance with a wide scope and high practicability. These bifunctional molecular catalysts offer a great opportunity to develop new fundamental processes for the straightforward hydrogenation of carboxylic acid derivatives as a powerful alternative for classical reduction using stoichiometric amounts of metal hydride reagents.

A novel method for the production of singlet oxygen from H 2 O 2 was developed. A combination of iodoarene (ArI), methyltrioxorhenium (MTO), and H 2 O 2 in the presence of pyridine as the co-catalyst efficiently produced singlet molecular oxygen ( 1 O 2 ) under biphasic conditions. The existence of 1 O 2 was demonstrated by trapping experiments with aromatic dienes, 1,3-cyclodienes, and alkenes. The mechanism of 1 O 2 production from the iodoarene/MTO/35 % H 2 O 2 system and the reaction scope was also discussed.

A series of half-sandwich iridium-based complexes bearing 1,4-benzenebis ( N,N ′-dicyclohexylamidine) (H 2 L 1 ) or 4,4′-bisphenylbis( N,N ′ - dicyclohexylamidine) (H 2 L 2 ) has been synthesized and characterized. Treatment of [Cp*IrCl 2 ] 2 (Cp* = η 5 -pentamethyl- cyclo pentadienyl) with deprotonated H 2 L 1 or H 2 L 2 at low temperature resulted in formation of binuclear complexes [Cp*IrCl] 2 ( L 1 ) and [Cp*IrCl] 2 ( L 2 ). They were chosen as precursors to construct macrocycles and cages. Tetranuclear metallamacrocycles [(Cp*Ir) 4 ( L 1 ) 2 (pyrazine) 2 ][OTf] 4 and [(Cp*Ir) 4 ( L 2 ) 2 (pyrazine) 2 ][OTf] 4 were assembled by the reaction of complex [Cp*IrCl] 2 ( L 1 ) or [Cp*IrCl] 2 ( L 2 ) with pyrazine after the removal of chloride from the iridium centers with silver salt AgOTf (OTf = O 2 SCF 3 ). When 2,4,6-tri(4-pyridyl)-1,3,5-triazine ( tpt ) is used instead of pyrazine under the same conditions, hexanuclear metallacages [(Cp*Ir) 6 ( L 1 ) 3 (tpt) 2 ][OTf] 6 and [(Cp*Ir) 6 ( L 2 ) 3 (tpt) 2 ][OTf] 6 were formed. Single-crystal X-ray analysis indicated that the cation of complex [(Cp*Ir) 4 ( L 1 ) 2 (pyrazine) 2 ][OTf] 4 is a rectangular structure, while the cation of complex [(Cp*Ir) 4 ( L 2 ) 2 (pyrazine) 2 ][OTf] 4 is seriously distorted, nearly to a tetrahedral state. Moreover, complexes [(Cp*Ir) 6 ( L 1 ) 3 (tpt) 2 ][OTf] 6 and [(Cp*Ir) 6 ( L 2 ) 3 (tpt) 2 ][OTf] 6 are prism-like cages with large cavity size, which can be prepared in very high yield in the absence of templates. Surprisingly, solutions of multinuclear complexes are very sensitive to carbon monoxide, in which the frameworks were destroyed, giving the binuclear complexes [(Cp*Ir) 2 (CO) 2 ( L 1 )][OTf] 2 and [(Cp*Ir) 2 (CO) 2 ( L 2 )][OTf] 2 .

The aim of this study was to synthesize in high product yield of anisotropic core-shell Fe 3 O 4 @Au magnetic nanoparticles and to investigate the effect of the immunomagnetic separation (IMS) volume on the capture efficiency. For these purposes and for the first time, we synthesized polyhedral magnetic nanoparticles composed of Fe 3 O 4 core Au shell. To synthesize magnetic gold anisotropic core-shell particles, the seed-mediated synthetic method was carried out. By choosing an appropriate amount of iron particles and growth solution the fine control of the seed-mediated approach is enabled. This led to the high product yield of anisotropic nanoparticles. The magnetic separation of these nanoparticles was easily accomplished, and the resulting nanoparticles were characterized with transmission electron microscopy (TEM), ultraviolet visible spectroscopy (UV–vis), near edge absorption fine structure (NEXAFS) spectroscopy, and X-ray diffraction (XRD). Additionally, the magnetic properties of the nanoparticles were examined. The magnetic nanoparticles (MNPs) were modified with antibody and interacted with Escherichia coli ( E. coli ). The high capture efficiency between the magnetic nanoparticles and E. coli is evidenced by SEM images. The capture efficiency decreases with an increase of volumes, and the highest capture efficiency was observed for E. coli in an experiment volume of 100 μL for magnetic nanoparticles. The percentage of captured E. coli for polyhedral nanoparticles was found to be approximately 95 % and for spherical nanoparticles 88 %, respectively.

Living organisms in Thailand are very diverse due to the unique geographical location of Thailand. The diversity of Thai bioresources has proven to be a rich source of biologically active compounds. The present review covers bioactive substances from Thai endophytic, marine-derived, insect pathogenic fungi and medicinal plants. Many new compounds isolated from Thai bioresources have diverse skeletons belonging to various classes of natural products. These compounds exhibited an array of biological activities, and some are of pharmaceutical interest. Bioactive compounds from Thai bioresources have not only attracted organic chemists to develop strategies for total synthesis, but also attracted (chemical) biologists to investigate the mechanisms of action. The chemistry and biology of some selected compounds are also discussed in this review.

Some species of nudibranchs (Mollusca) protect themselves from predatory attacks by storing defensive terpene chemicals acquired from dietary sponges (Porifera) in specialized body parts called MDFs (mantle dermal formations), often advertising their unpalatability to potential predators by means of bright coloration patterns. Consequently, the survival of these trophic specialist species is closely related to the possibility of obtaining the defensive tools from sponges that live in their immediate vicinity; therefore, it is important to determine as precisely as possible the chemical composition of nudibranch extracts prior to any ecological studies addressing issues that involve their alimentary behavior and their defensive strategies, including the significance of their color patterns. Some of our recent studies on the chemical composition of terpene extracts from nudibranchs belonging to the genera Chromodoris and Hypselodoris are summarized. We also report the development of a method to assay extracts and purified metabolites for their feeding deterrent activity against co-occurring generalist predators. In a recent chemoecological study, showing that repugnant terpene chemicals are accumulated at extremely high concentrations in exposed parts of the nudibranchs’ bodies, the feeding deterrence assays were carried out on the generalist marine shrimp Palaemon elegans , very common in the Mediterranean. We have modified this assay for use with the Australian shrimp species P. serenus , and confirmed the ecological validity of the assay by analysis of extracts from species of sponges and mollusks that live in the same habitat as P. serenus . The deterrent properties of haliclonacyclamine alkaloids isolated from the sponge Haliclona sp. were demonstrated, with the alkaloid mixture demonstrating palatability deterrence at concentrations as low as 0.05 mg/mL, and complete deterrence at 0.75 mg/mL. In contrast, the diterpene thuridillin metabolites from the sacoglossan mollusk Thuridilla splendens did not deter feeding by P . serenus .

This document provides some basic rules and guidelines regarding the use and creation of abbreviations for the names of polymers. An extended list of currently used abbreviations for polymers and polymeric materials is appended.

A generic definition of oxidation state (OS) is formulated: “ The OS of a bonded atom equals its charge after ionic approximation ”. In the ionic approximation, the atom that contributes more to the bonding molecular orbital (MO) becomes negative. This sign can also be estimated by comparing Allen electronegativities of the two bonded atoms, but this simplification carries an exception when the more electronegative atom is bonded as a Lewis acid. Two principal algorithms are outlined for OS determination of an atom in a compound; one based on composition, the other on topology. Both provide the same generic OS because both the ionic approximation and structural formula obey rules of stable electron configurations. A sufficiently simple empirical formula yields OS via the algorithm of direct ionic approximation (DIA) by these rules. The topological algorithm works on a Lewis formula (for a molecule) or a bond graph (for an extended solid) and has two variants. One assigns bonding electrons to more electronegative bond partners, the other sums an atom’s formal charge with bond orders (or bond valences) of sign defined by the ionic approximation of each particular bond at the atom. A glossary of terms and auxiliary rules needed for determination of OS are provided, illustrated with examples, and the origins of ambiguous OS values are pointed out. An electrochemical OS is suggested with a nominal value equal to the average OS for atoms of the same element in a moiety that is charged or otherwise electrochemically relevant.