Metal tellurite oxides: Lone-pair-enabled coordination chemistry, polymerized architectures, and functional materials opportunities

Metal-containing ionic liquids are expected to behave as functional materials that combine the unique properties of ionic liquids with additional magnetic, electric, catalytic or emission properties. (Abbott et al. 2008; Nockemann et al., 2006, 2009; Scheeren et al., 2006) Ionic liquids of metal complexes which contain metal ions in their molecular structures (metallo-ILs) are particularly applicable in many fields as task-specific soft materials with many possibilities for molecular design. (Lee et al., 2004; Lin et al. , 2005; Binnemans, 2007) The first systematic studies of metallo-ILs have been performed for the mixtures of 1ethylpyridinium bromide and aluminum(III) chloride (Hurley & Wier, 1951). Since then the halogenoaluminate(III) and the alkylhalogenoaluminate(III) ionic liquids have been the most extensively studied systems (Hussey, 1988). The conventional metallo-ILs can be formed by the complexation reactions of simple anionic species with neutral compounds such as: AlCl3 + EMICl ⇌ EMI+AlCl4 −, where EMI+ is 1-ethyl-3-methyl-imidazolium cation. These ionic liquids provide a useful extension to the range of solvents that are available for synthetic chemistry (Welton, 1999). Numerous transition metal chlorides have been shown to form well-defined anionic complexes in basic haloaluminate ionic liquids. When transition metals are bound to neutral ligands in ILs to form transition-metal complex cations, the salts tend to have higher melting points compared with conventional ILs. (Lee et al., 2004; Lin & Vasam, 2005) However, for such kinds of metallo-ILs there are potential applications in a wide range of fields due to their affinity for anionic surfaces which are present abundantly in nature (Israelachvili, 1992) and for carbon surfaces rich in π-electron density by virtue of cation-π interactions. (Ma & Dougherty, 1997; Fukushima et al., 2003; Zhang & Cui, 2009) On the other hand, protic ionic liquids (PILs) have recently attracted attention for their variable proton activities (Yoshizawa et al., 2003; Belieres & Angell, 2007; Angell et al., 2007; Greaves & Drummond, 2008). Although the first room-temperature ionic liquid is ethylammonium nitrate (= EAN) which is the simplest PIL, a large part of the ILs hitherto

The computationally assisted, accelerated design of inorganic functional materials often relies on the ability of a given electronic structure method to return the correct electronic ground state of the material in question. Outlining difficulties with current density functionals and wave function-based approaches, we highlight why double hybrid density functionals represent promising candidates for this purpose. In turn, we show that PBE0-DH (and PBE-QIDH) offers a significant improvement over its hybrid parent functional PBE0 [as well as B3LYP* and coupled cluster singles and doubles with perturbative triples (CCSD(T))] when computing spin-state splitting energies, using high-level diffusion Monte Carlo calculations as a reference. We refer to the opposing influence of Hartree-Fock (HF) exchange and MP2, which permits higher levels of HF exchange and a concomitant reduction in electronic density error, as the reason for the improved performance of double-hybrid functionals relative to hybrid functionals. Additionally, using 16 transition metal (Fe and Co) complexes, we show that low-spin states are stabilised by increasing contributions from MP2 within the double hybrid formulation. Furthermore, this stabilisation effect is more prominent for high field strength ligands than low field strength ligands.

Redox-active ligands in coordination chemistry not only modulate the reactivity of the bound metal center but also serve as electron reservoirs to store redox equivalents. Among many applications in contemporary chemistry, the scope of redox-active ligands in biology is exemplified by the porphyrin radicals in the catalytic cycles of multiple heme enzymes (e.g., cytochrome P450, catalase) and the chlorophyll radicals in photosynthetic systems. This Account reviews the discovery of two redox-active ligands inspired by oligopyrrolic fragments found in biological settings as products of heme metabolism.Linear oligopyrroles, in which pyrrole heterocycles are linked by methylene or methine bridges, are ubiquitous in nature as part of the complex, multistep biosynthesis and degradation of hemes and chlorophylls. Bile pigments, such as biliverdin and bilirubin, are common and well-studied tetrapyrroles with characteristic pyrrolin-2-one rings at both terminal positions. The coordination chemistry of these open-chain pigments is less developed than that of porphyrins and other macrocyclic oligopyrroles; nevertheless, complexes of biliverdin and its synthetic analogs have been reported, along with fluorescent zinc complexes of phytobilins employed as bioanalytical tools. Notably, linear conjugated tetrapyrroles inherit from porphyrins the ability to stabilize unpaired electrons within their π system. The isolated complexes, however, present helical structures and generally limited stability.Smaller biopyrrins, which feature three or two pyrrole rings and the characteristic oxidized termini, have been known for several decades following their initial isolation as urinary pigments and heme metabolites. Although their coordination chemistry has remained largely unexplored, these compounds are structurally similar to the well-established tripyrrin and dipyrrin ligands employed in a broad variety of metal complexes. In this context, our study of the coordination chemistry of tripyrrin-1,14-dione and dipyrrin-1,9-dione was motivated by the potential to retain on these compact, versatile platforms the reversible ligand-based redox chemistry of larger tetrapyrrolic systems.The tripyrrindione ligand coordinates several divalent transition metals (i.e., Pd(II), Ni(II) Cu(II), Zn(II)) to form neutral complexes in which an unpaired electron is delocalized over the conjugated π system. These compounds, which are stable at room temperature and exposed to air, undergo reversible one-electron processes to access different redox states of the ligand system without affecting the oxidation state and coordination geometry of the metal center. We also characterized ligand-based radicals on the dipyrrindione platform in both homoleptic and heteroleptic complexes. In addition, this study documented noncovalent interactions (e.g., interligand hydrogen bonds with the pyrrolinone carbonyls, π-stacking of ligand-centered radicals) as important aspects of this coordination chemistry. Furthermore, the fluorescence of the zinc-bound tripyrrindione radical and the redox-switchable emission of a dipyrrindione BODIPY-type fluorophore showcased the potential interplay of redox chemistry and luminescence in these compounds. Supported by computational analyses, the portfolio of properties revealed by this investigation takes the tripyrrindione and dipyrrindione motifs of heme metabolites to the field of redox-active ligands, where they are positioned to offer new opportunities for catalysis, sensing, supramolecular systems, and functional materials.

The boronyl anion (BO-) is a more polarized, isoelectronic analogue of CO, rendering it a promising ligand for expanding "carbonyl-like" coordination chemistry into realms of heightened reactivity and electronic diversity. Intrinsically, BO- differs fundamentally from CO in that its frontier molecular orbitals are shifted upward, making BO- a stronger σ donor yet a weaker π acceptor. Herein, we present a comprehensive theoretical investigation into the isomerism of monoboronyl complexes M(BO)- and M(OB)- across the 3d series (M = Sc-Zn), using DFT, CCSD(T) calculations and EDA-NOCV analyses. Geometrically, both isomers adopt a predominantly linear configuration. The B-bound isomer is favored for nearly the entire 3d series, with the exception of Sc, Ti and Mn, for which the O-bound isomer becomes the electronic ground state. EDA-NOCV calculations show that electrostatic attraction constitutes the dominant attraction (≈58-72%), with orbital interactions being governed primarily by the σ-type interaction. The subtle Sc/Ti/Mn preference for O-binding is attributed to a competitive balance between Pauli repulsion and attractive interaction. Extending our study to 4d(Pd) and 5d(Pt) congeners further amplifies the preference for B-coordination and highlights the increasing significance of π-type orbital interactions for the heavier metals. This work not only expands the isoelectronic-ligand concept beyond CO but also offers a robust theoretical foundation for developing new boronyl-based coordination motifs and functional materials.

The design of transition-metal complexes (TMCs) has drawn much attention over the years because of their important applications as metallodrugs and functional materials. In this work, we present an extension of our recently reported approach, LigandDiff [Jin et al. J. Chem. Theory Comput. 20, 4377(2024)]. The new model, which we call multi-LigandDiff, is more flexible and greatly outperforms its predecessor. This scaffold-based diffusion model allows de novo ligand design with either existing ligands or without any ligand. Moreover, it allows users to predefine the denticity of the generated ligand. Our results indicate that multi-LigandDiff can generate well-defined ligands and is transferable to multiple transition metals and coordination geometries. In terms of its application, multi-LigandDiff successfully designed 338 Fe(II) spin-crossover (SCO) complexes from only 47 experimentally validated SCO complexes. And these generated complexes are configurationally diverse and structurally reasonable. Overall, the results show that multi-LigandDiff is an ideal tool to design novel TMCs from scratch.

8 - Thin Film MEMS

At the onset of the nanotechnology age, molecular designing of materials and single molecule studies are opening wide possibilities of using molecular systems in electronic and photonic devices, as well as in technological applications based on molecular switching or molecular recognition. In this sense, inorganic chemists are privileged by the possibility of using the basic strategies of coordination chemistry to build up functional supramolecular materials, conveying the remarkable chemical properties of the metal centers and the characteristics of the ancillary ligands. Coordination chemistry also provides effective self-assembly strategies based on specific metal-ligand affinity and stereochemistry. Several molecular based materials, derived from inorganic and metal-organic compounds are focused on this article, with emphasis on new supramolecular porphyrins and porphyrazines, metal-clusters and metal-polyimine complexes. Such systems are also discussed in terms of their applications in catalysis, sensors and molecular devices.

For Abstract see ChemInform Abstract in Full Text.

This chapter focuses on the advances made in the chemistry of metal–metal quadruply bonded complexes over the last 5 years and is split into three main themes: electron transfer, reactivity and coordination chemistry. The question of electron (de)localisation is examined through the study of ground-state mixed valence complexes and their photo-excited state dynamics. Fundamental studies of metal–metal bonding allow the exploration of new modes of reactivity and low-coordinate compounds which are finding use in catalysis. Additionally, coordination chemistry allows the tuning of molecular properties and this can have profound effects on the electronic structures of functional molecular materials.

Despite being attractive targets for functional materials, the discovery of transition metal complexes with high-throughput computational screening is challenged by the amount of feasible coordination numbers, spin states, or oxidation states and the potentially large sizes of ligands. To overcome these limitations, we take inspiration from organic chemistry where full enumeration of neutral, closed shell molecules under the constraint of size has enriched discovery efforts. We design monodentate and bidentate ligands from scratch for the construction of mononuclear, octahedral transition metal complexes with up to 13 heavy atoms (i.e., metal, C, N, O, P, or S). From > 11,000 theoretical ligands, we develop a heuristic score for ranking a chemically feasible 2,500 ligand subset, only 71 of which were previously included in common organic molecule databases. We characterize the top 20% of scored ligands with density functional theory (DFT) in an octahedral homoleptic ligand database (OHLDB). The OHLDB contains i) the geometry optimized structures of 1,250 homoleptic octahedral complexes obtained from the enumerated pool of ligands and an open-shell transition metal (M(II)/M(III), M = Cr, Mn, Fe, or Co), and ii) the resulting high-spin/low-spin adiabatic electronic energies (ΔEH-L) obtained with hybrid DFT. Over the OHLDB, we observe structure–property (i.e., ΔEH-L) relationships different from those expected on the basis of ligand field arguments or from our prior data sets. Finally, we demonstrate how incorporating OHLDB data into artificial neural network (ANN) training improves ANN out-of-sample performance on much larger transition metal complexes.

Elaborated molecular architectures, specifically those containing a 2-aminophenoxazinone scaffold, belong to one of the most ubiquitous and prominent classes of heterocyclic frameworks, going from natural products to biologically active pharmaceutical molecules and from agrochemicals to functional materials and polymers. Therefore, efficient synthetic strategies for the assembly of 2-aminophenoxazinone frameworks are always in demand and have gained attention in academic and industrial communities. Methodologies that involve cascade reactions generally catalyzed by transition metal complexes, such as iron, cobalt, manganese, copper, and zinc complexes, have stood out as a representative approach. Over the past few decades, a great deal of versatile, atom-economic, and straightforward protocols have been reported for the generation of value-added 2-aminophenoxazinone frameworks in a sustainable, powerful, and applicable manner. The state-of-the-art methodologies toward the construction of 2-aminophenoxazinone skeletons are summarized in this review, which could be divided into four categories: (1) construction of 2-aminophenoxazinone compounds catalyzed by transition metal complexes; (2) construction of 2-aminophenoxazinone compounds catalyzed by biosynthetic enzymes; (3) synthetic process routes of 2-aminophenoxazinone compounds; and (4) construction of 2-aminophenoxazinone compounds via other innovative methods.

As the use of free electron laser (FEL) sources increases, so do the findings mentioning non-linear phenomena occurring at these experiments, such as saturable absorption, induced transparency and scattering breakdowns. These are well known among the laser community, but are still rarely understood and expected among the X-ray community and to date lack tools and theories to accurately predict the respective experimental parameters and results. We present a simple theoretical framework to access short X-ray pulse induced light–matter interactions which occur at intense short X-ray pulses as available at FEL sources. Our approach allows to investigate effects such as saturable absorption, induced transparency and scattering suppression, stimulated emission, and transmission spectra, while including the density of state influence relevant to soft X-ray spectroscopy in, for example, transition metal complexes or functional materials. This computationally efficient rate model based approach is intuitively adaptable to most solid state sample systems in the soft X-ray spectrum with the potential to be extended for liquid and gas sample systems as well. The feasibility of the model to estimate the named effects and the influence of the density of state is demonstrated using the example of CoPd transition metal systems at the Co edge. We believe this work is an important contribution for the preparation, performance, and understanding of FEL based high intensity and short pulse experiments, especially on functional materials in the soft X-ray spectrum.

Preface from the editorsThe energy requirement increases exponentially and becomes an important issue for the entire world due to its significant impact on environmental damage and human health. Therefore, it is an urgent priority for the researchers to design new materials that can fulfill the energy requirements and to reduce the environmental risks and health problems in the same time. Functionalization of materials can be a potential response to the growing challenges in the energy, environment and health applications. Materials with improved functional has not only attracted more attention from researchers, but also be required in a wide range of advanced technology fields. This demand leads to the rapid global development of the new and novel materials.The International Conference on Current Progress in Functional Materials 2016 (ISCPFM 2016) is the first international conference in functional materials organized by the Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Indonesia. It was held in Bali (Indonesia) and accommodated two days of intense discussion regarding the current progress in the functional material for energy, environment and health applications. Three plenary speakers from Japan and UK have featured the fascinating results in experimental works, while the other three from US, Japan, and China gave compelling presentations from the theoretical point of views. Concurrent sessions were covered a more wide range of topics and issues, including low-dimensional, nano and 2D materials, metals, metal oxides, organometals and coordination chemistry, polymers, ceramics and composite materials, biomaterials as well as computation and simulation of materials. After a peer review process, 62 papers have been accepted to be published in the conference proceeding.We would like to thank all of the reviewers for their time and effort to review and select the papers and also express our heartfelt appreciation to the faculty’s conference proceeding teams to finalize the articles to be included in the proceeding. It would be difficult for us to finish the proceeding without the commitment and the willpower from the researchers and technical teams to involve in all processes. We have enjoyed working hand in hand with the reviewers and the faculty’s proceedings teams. It has been an honor for us to have the chance to become the editors of the proceeding.We are very grateful and highly appreciate the contribution of various parties who have been involved directly and indirectly- the international advisory board, the steering committee, the organizing committee, the scientific committee, the program committee and financial support from Universitas Indonesia- for helping to execute the conference and the proceedings. Finally, we thank all participants and authors for their contributions.Depok, March 2017EditorsIvandini Tribidasari A.Djoko Triyono

Functional materials containing luminescent octahedral halide clusters of molybdenum and tungsten: Diversity of synthetic approaches and binding modes

Metal-catalyzed cyclization reactions have become a powerful and efficient approach for the stereoselective construction of both carbocyclic and heterocyclic ring systems. Transition metal complexes, with their ability to activate and selectively functionalize organic substrates, have revolutionized various areas of synthetic chemistry. This review highlights recent advancements in metal-catalyzed cyclization reactions, especially in the synthesis of nitrogen-containing heterocycles like imidazoles, pyridines, pyrimidines, and indoles. These advancements have significantly impacted fields such as natural product synthesis, pharmaceuticals, functional materials, and organic electronics. Novel catalytic systems, ligand designs, and reaction conditions continue to expand the capabilities of these reactions, driving further the progress made in synthetic organic chemistry. This review provides a comprehensive overview of recent research.