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This paper reports on green chemistry approaches to the molecular design and synthesis of cheap, efficient and eco-friendly electrocatalysts of the hydrogen evolution reaction (HER). The title clathrochelates (including first those do not containing sulfur derivatives as “catalytic poisons”) were prepared using nucleophilic substitution of their chloroclathrochelate precursors and characterized by analytical, spectral and XRD methods. These complexes showed the HER 2 H+/H2electrocatalytic activity in the solutions. They form the Langmuir monolayers and possess a high physisorption on activated carbon (AC, up to 0.55 mmol·g–1) and reduced graphene oxide (RGO, up to 0.33 mmol·g–1). Contrary that on carbon paper (CP) is very low. Therefore, AC- or RGO-containing clathrochelate-immobilized components are suitable for preparation of hybrid CP-based cathodes, allowing to substantially increase a surface concentration of electrocatalytically active centers up to 0.5 μmol·m–2. Cyclic voltammetry data suggest that the electrochemically generated cobalt(I) complexes, as the catalytically active intermediates, are stable and most prospective candidates for electrocatalytic hydrogen production. Clathrochelate-based single-atom catalysts were prepared in accordance with basic principles of green chemistry. They are derivatives of abundant and cheap 3d-biometals and low-toxic α-dioximes and possess an extremely high atomic utilization efficiency matching the “economy of atoms” principle. Nowadays, the carbon-supported metallic platinum is used as HER catalyst. The reserves of this noble and expensive metal on the Earth are limited and its replacement by such cheap and abundant HER materials will accelerate the development and implementation of green hydrogen-producing technologies. The recommendations on chemical structures of optimal molecular electrocatalysts were evaluated.

The redox state of the phthalocyanine in sandwich lanthanide complexes is crucial for their applications. In this work, we demonstrate that the cation-induced supramolecular assembly of crown-substituted phthalocyanine lanthanide complexes Ln[(15C5)4Pc]2can be used to control the redox state of the ligand simultaneously with the coordination sphere of the central metal. We achieve unprecedented redox switching of phthalocyanine ligands in a double-decker Gd(III) complex, resulting from the intramolecular inclusion of potassium cations between the decks with simultaneous twisting of the ligands (the skew angle between them decreases from 44.61 to 0.21°). Such a structural change leads to an increase in the deck-to-deck distance and drastically facilitates ligand reduction. This process was shown to be anion-dependent: only potassium salts of weak acids (KOPiv and KOAc) induce intramolecular inclusion of cations with redox switching in contrast to salts of strong acids (KBr, KOPic, KSCN, and KPF6), where such a redox process does not occur. This breakthrough opens new avenues for controlling the electrochromic properties, of phthalocyanines, along with other properties, such as electrical conductivity, optics, etc.

Transmetalation of the bis{triethylantimony(V)}-capped iron(II) tris-α-dioximate with n-butylboronic acid afforded the mixed antimony, boron cross-linked clathrochelate with single reactive antimony(V)-based apical fragment. This macrobicyclic precursor easily underwent the transmetalation reactions with germanium and titanium(IV) alkoxides to give the rod-like and angular FeII2MIV-trinuclear bis-clathrochelates. Those of the aforementioned diantimony(V)-capped complex with 3- and 4-carboxyphenylboronic acids afforded the monoboron-capped iron(II) semiclathrochelates, undergoing a double-cyclization (macrobicyclization) with germanium- and titanium(IV)-based capping agents. The reactions in the low-temperature range unexpectedly gave the stable 2:1 associates, formed by the bridging of two carboxyl-terminated macrobicyclic molecules of the mixed carboxylboron, triethylantimony-capped iron(II) clathrochelate with a triethylantimony(V)-based linker fragment. The obtained complexes were characterized using elemental analysis, MALDI-TOF, 1H and 13C{1H} NMR and UV–vis spectra, and single-crystal XRD experiments. The encapsulated iron(II) ion in their 3D-molecules is situated almost in the center of its FeN6-coordination polyhedron possessing a truncated trigonal-pyramidal geometry. Fe–N distances fall in the range 1.887(7)–1.945(4) Å characteristic of the low-spin iron(II) complexes. The cross-linking titanium and germanium(IV) ions in the corresponding bis-clathrochelate molecules form the octahedral MIVO6-coordination polyhedra, the MIV–O distances of which vary from 1.946(2) to 1.964(2) Å and from 1.879(7) to 1.907(6) Å, respectively.

Unprecedented iron-based silsesquioxane/acetylacetonate complexes were synthesized. The intriguing cage-like structure of compounds is alkaline metal-dependent: the Fe2Li2complex includes condensed Si6-silsesquioxane and four acetylacetonate ligands; the Fe4Na4complex exhibits two cyclic Si4-silsesquioxane and eight acetylacetonate ligands, while the Fe3K3complex features two cyclic Si3-silsesquioxane and six acetylacetonate ligands. The latter case is the very first observation of small trimeric silsesquioxane ligands in the composition of cage-like metallasilsesquioxanes. The Fe4Na4-based complex exhibits a record high activity in the oxidation of inert alkanes with peroxides (55% yield of oxygenates in cyclohexane oxidation). It also acts as a catalyst in the cycloaddition of CO2with epoxides, leading to cyclic carbonates in good yields (58–96%).

The study describes a new feature in the self-assembly of cagelike manganese-based phenylsilsesquioxanes consisting of the strong influence of acetone solvates on the formation of a cage structure. By this convenient approach, a series of new tri and tetra manganese-based silsesquioxane complexes with (i) 1,10-phenanthroline, (ii) pyrazine, or (iii) 3,5-dimethylpyrazole (dmpzH) ligands were isolated and characterized. Single-crystal X-ray diffraction studies established the molecular architectures of all of the synthesized products. Several compounds represent extraordinary types of cagelike metallasilsesquioxane (CLMS) molecular architectures. Pyrazine- and dmpzH-based Mn3Na3compounds exhibit total oxidation of initial Mn(II) ions to the Mn(III) state. They present relatively weak antiferromagnetic interactions between the manganese centers. The catalytic performance of a representative precatalyst Mn–CLMS compound, [(Ph6Si6O12)2Mn3Na3(dmpzH)3(acetone)3(H2O)], was investigated for the microwave-assisted oxidation of toluene to obtain benzaldehyde, benzyl alcohol, and benzoic acid as the main products. The effects of reaction parameters were studied, and under optimized conditions, using the tBuOOH oxidant, the oxygenated products were formed with a total yield of 54%, under microwave irradiation at 100 °C after 6 h, with 70% selectivity toward the formation of benzoic acid.

This study reports a novel family of cage manganesesilsesquioxanes prepared via complexation with bathophenanthroline (4,7-diphenyl-1,10-phenanthroline). The resulting Mn4-, Mn6Li2-, and Mn4Na-compounds exhibit several unprecedented cage metallasilsesquioxane structural features, including intriguing self-assembly of silsesquioxane ligands. Complexes were tested in vitrofor fungicidal activity against seven classes of phytopathogenic fungi. The representative Mn4Na-complex acts as a catalyst in the cycloaddition of CO2to epoxides under solvent-free conditions to form cyclic carbonates in good yields.

Ten copper-based cage silsesquioxanes were prepared via convenient self-assembly synthesis employing halides of different quaternary ammonium cations, namely, Me4NBr, Et4NBr, PhMe3NCl, BzMe3NCl, and BzEt3NCl. This approach led to cages of similar Cu4M2nuclearity (M = Rb, K, or Na). Sandwich-like structures of all compounds were established by single-crystal X-ray diffraction studies using synchrotron radiation. In all products, anionic cages are based on two cyclic silsesquioxane [Ph6Si6O12] ligands, coordinating to a central hexagonal CuII4M2motif with a 2M6-1 topology. The complexes include two charge balancers, namely, quaternary N-cations located at the external (crown ether-like) positions to cage fragments. Selected compounds were tested as homogeneous multicopper(II) catalysts in a series of model reactions, such as the mild oxidation and carboxylation of alkanes, including inert gaseous C2–C4saturated hydrocarbons. This study extends the types of synthetic approaches and family of ionic metallasilsesquioxanes with promising structural features and catalytic properties.

Stabilization of different conformers of sandwich phthalocyaninates by changing the solvation environment has been demonstrated with the examples of new heteroleptic yttrium(III) and terbium(III) triple-decker complexes [(BuO)8Pc]M[(BuO)8Pc]M[(15C5)4Pc](where M = Y or Tb, [(BuO)8Pc]2–= octa-n-butoxyphthalocyaninato ligand, and [(15C5)4Pc]2–= tetra-15-crown-5-phthalocyaninato ligand). To this end, we have performed a comprehensive crystallographic characterization of two solvates formed by the Y(III) complex with either toluene or dichloromethane. In the solvate with toluene, both pairs of Pc ligands are in staggered conformations, providing both metal cations with a square-antiprismatic environment. In contrast, in the solvate with dichloromethane, only one cation between the BuO- and 15C5-substituted ligands remains in a square-antiprismatic polyhedron, while the pair of BuO-substituted ligands switches to a gauche conformation. In both solvates, the staggered conformations are stabilized by weak interactions of peripheral substituents with solvent molecules. Detailed analysis of the 1H NMR spectra of the isostructural Tb(III) complex in aliphatic and aromatic solvents demonstrates that the stabilization of the corresponding conformations by solvation is also valid in the solution state, resulting in an increase in the axial component of the magnetic susceptibility tensor as the symmetry decreases from staggered to gauche. Thus, solvation-induced conformational switching of lanthanide trisphthalocyaninates can be used as a tool to control their magnetic properties.

Within the sweeping research on the design of new coordination polymers and related metal–organic architectures, the use of silsesquioxane derivatives as important organosilicon building blocks has been poorly explored, despite a number of unique structural and functional characteristics of the resulting products. The present study thus describes an extended series (eight examples) of heterometallic Cu4Cs4and Cu4Rb4coordination polymers with the common formula [(PhSiO1.5)12(CuO)4(AO0.5)4(Solv)x]n·nSolv (A is Cs or Rb; Solv refers to ligands and/or solvate molecules including H2O, EtOH, BuOH, DMF, and DMSO in various combinations), which are based on cagelike coppersilsesquioxanes as nontrivial secondary building units. The concept of supramolecular design was implemented in a straightforward way by the assembly of coppersilsesquioxane cages using large and coordination-versatile cesium or rubidium cations. The structures of all products were established by single-crystal X-ray diffraction studies mainly using synchrotron radiation. The resulting Cu4Cs4- and Cu4Rb4-silsesquioxanes exhibit an extracage location of the alkali-metal cations, which enables the interconnectivity of neighboring cages into 1D, 2D, or 3D coordination polymer architectures. The unique feature of such architectures is a realization of metallocene Cs···π (Rb···π) joints, providing tightly connected nonporous coordination polymers. A topological classification of cages and coordination polymer networks was performed. Some of the obtained compounds also represent the first examples of Rb-containing silsesquioxanes. The selected products were also tested as homogeneous catalysts in the oxidation and hydrocarboxylation of C5–C8cycloalkanes. This study extends the structural types of heterometallic silsesquioxane cages that can be efficiently applied to the design of functional coordination polymers.

A series of heteroleptic square-planar Pt and Pd complexes with bis(diisopropylphenyl) iminoacenaphtene (dpp-Bian) and Cl, 1,3-dithia-2-thione-4,5-dithiolate (dmit), or 1,3-dithia-2-thione-4,5-diselenolate (dsit) ligands have been prepared and characterized by spectroscopic techniques, elemental analysis, X-ray diffraction analysis, and cyclic voltammetry (CV). The intermolecular noncovalent interactions in the crystal structures were assessed by density functional theory (DFT) calculations. The anticancer activity of Pd complexes in breast cancer cell lines was limited by their solubility. Pd(dpp-Bian) complexes with dmit and dsit ligands as well as an uncoordinated dpp-Bian ligand were devoid of cytotoxicity, while the [Pd(dpp-Bian)Cl2] complex was cytotoxic. On the contrary, all Pt(dpp-Bian) complexes demonstrated anticancer activity in a low micromolar concentration range, which was 8–20 times higher than the activity of cisplatin, and up to 2.5-fold selectivity toward cancer cells over healthy fibroblasts. The presence of a redox-active dpp-Bian ligand in Pt and Pd complexes resulted in the induction of reactive oxygen species (ROS) in cancer cells. In addition, these complexes were able to intercalate into DNA, indicating the dual mechanism of action.

This study reports intriguing features in the self-assembly of cage copper(II) silsesquioxanes in the presence of air. Despite the wide variation of solvates used, a series of prismatic hexanuclear Cu6cages (1–5) were assembled under mild conditions. In turn, syntheses at higher temperatures are accompanied by side reactions, leading to the oxidation of solvates (methanol, 1-butanol, and tetrahydrofuran). The oxidized solvent derivatives then specifically participate in the formation of copper silsesquioxane cages, allowing the isolation of several unusual Cu8-based (6and 7) and Cu6-based (8) complexes. When 1,4-dioxane was applied as a reaction medium, deep rearrangements occurred (with a total elimination of silsesquioxane ligands), causing the formation of mononuclear copper(II) compounds bearing oxidized dioxane fragments (9and 11) or a formate-driven 1D coordination polymer (10). Finally, a “directed” self-assembly of sil- and germsesquioxanes from copper acetate (or formate) resulted in the corresponding acetate (or formate) containing Cu6cages (12and 13) that were isolated in high yields. The structures of all of the products 1–13were established by single-crystal X-ray diffraction, mainly based on the use of synchrotron radiation. Moreover, the catalytic activity of compounds 12and 13was evaluated toward the mild homogeneous oxidation of C5–C8cycloalkanes with hydrogen peroxide to form a mixture of the corresponding cyclic alcohols and ketones.

The first [4]radialene complex of zirconocene 1Zr-Phwas obtained by the reaction of Negishi’s reagent with 1,4-diphenylbutadiyne. The structure of 1Zr-Phhas been determined by X-ray diffraction. In addition, organometallic [4]radialenes of group 4 metallocenes were also studied with Raman spectroscopy and density functional theory calculations. The theoretical study illustrates the thermodynamic stability, electronic structure, and conjugation/aromaticity of organometallic radialenes with Ti, Zr, Hf, and various substituents.

AbstractThe bonds between lysozyme molecules and precipitant ions in single crystals grown with chlorides of several metals are analysed on the basis of crystal structure data. Crystals of tetragonal hen egg lysozyme (HEWL) were grown with chlorides of several alkali and transition metals (LiCl, NaCl, KCl, NiCl2and CuCl2) as precipitants and the three-dimensional structures were determined at 1.35 Å resolution by X-ray diffraction method. The positions of metal and chloride ions attached to the protein were located, divided into three groups and analysed. Some of them, in accordance with the recently proposed and experimentally confirmed crystal growth model, provide connections in protein dimers and octamers that are precursor clusters in the crystallization lysozyme solution. The first group, including Cu+2, Ni+2and Na+1cations, binds specifically to the protein molecule. The second group consists of metal and chloride ions bound inside the dimers and octamers. The third group of ions can participate in connections between the octamers that are suggested as building units during the crystal growth. The arrangement of chloride and metal ions associated with lysozyme molecule at all stages of the crystallization solution formation and crystal growth is discussed.Communicated by Ramaswamy H. Sarma

A complete screening of compositions of crystallizing products of hybrid perovskites in the most popular dimethylformamide (DMF)/dimethyl sulfoxide (DMSO) solvents is performed for various cations (FA+/MA+) and anions (I–/Br–). We found four new solvate phases of formamidinium hybrid perovskites, (FA)2Pb3I8·4DMF, FAPbI3·2DMF, (FA)5Pb2I9·0.5DMSO, and even the bromide solvate (FA)2PbBr4·DMSO. These compounds are observed for the first time, and their refined crystal structures showed large cells of unique types dependent on solvent and perovskite compositions. We also monitored crystallization pathways of multicompositional thin films and identified phases that are able to crystallize from mixed cation and anion solutions. Based on the obtained data, we performed a deep analysis of the structural peculiarities of all the solvate phases observed in the screened compositional space and discussed how the solution composition would predetermine the early stages of crystallization of target perovskite films.

An unusual skeletal rearrangement of piperazine into ethylenediamine has been observed for the first time as a result of an attempt to synthesize a piperazine-linked metal–organic framework (MOF) using cage Cu(II),Na-phenylsilsequixane as a potential building block. Instead of the expected “metallasilsesquioxane-based MOF”, a Cu6complex 1coordinated both by silsesquioxane and ethylenediamine ligands was isolated. An effort to reproduce this result via direct interaction of Cu-phenylsilsequioxane and ethylenediamine surprisingly afforded two other types of complexes, copper–sodium 2and copper 3ionic products. Cationic components in both products 2and 3are represented by (i) copper and sodium ions (in the case of 2) or (ii) copper ions exclusively (in the case of 3) coordinated by ethylenediamine ligands. Both complexes 2and 3include Si6-based condensed silsesquioxane fragments serving as anionic components of the products. Symptomatically, the types of the Si6-frameworks in 2and 3are drastically different. More specifically, the Si6unit in 2is an unprecedented distorted silsesquioxane skeleton consisting of two condensed tetramembered rings. Structural features of compounds 1–3were established by single crystal X-ray diffraction. Compound 2was found to catalyze the oxidation of cyclohexane to cyclohexanol and cyclohexanone with H2O2(a mixture of these products was obtained after adding PPh3to the reaction solution) as well as the transformation of cyclohexanol to cyclohexanone under the action of tert-butyl hydroperoxide.

Spiro[imidazol-5-one-4,1′-cyclopropanes] behave as donor–acceptor (D–A) cyclopropanes in a formal cycloaddition reaction with aldehydes. The activation of such type of cyclopropanes is achieved with an equivalent of Brønsted acid. The reaction proceeds in high yields of 51–92% and demonstrates moderate diastereoselectivity at the quaternary stereocenter, which is determined by the electron-donating nature of the aldehyde partner. The ease of separation of stereoisomers allowed the creation of a library of 44 spiroannulated tetrahydrofurans with various substitution patterns.

Background: Quinoxaline 1,4-dioxides have a broad range of biological activity that causes a growing interest in their derivatives for drug discovery. Recent studies demonstrated that quinoxaline 1,4- dioxides have a promising anticancer activity and good hypoxia-selectivity. Objective: The preparation, isolation, structure characterization, and screening for anticancer activity of the first representatives of 6-substituted quinoxaline-2-carbonitrile 1,4-dioxides have been described. Materials and Methods: A series of 7- and 6-halogeno-3-phenylquinoxaline-2-carbonitrile 1,4-dioxides was synthesized by the Beirut reaction. The cytotoxicity was assessed by MTT test (72 h incubation) in normoxia (21% O2) and hypoxia (1% O2) conditions. Results: We found that during the Beirut reaction between a benzofuroxan bearing an electron withdrawing group and benzoylacetonitrile in the presence of triethylamine, in addition to well-known 7-substituted quinoxaline-2-carbonitrile 1,4-dioxides 7-11a, the 6-isomers 7-11b are formed. Moreover, the yield of the 6- isomers increased with the increase in the electron-withdrawing character of the substituent. For benzofuroxans with CO2Me and CF3 groups, 6-substituted quinoxaline-2-carbonitrile 1,4-dioxides 10-11b were the major products. Despite similarities in physicochemical and spectroscopic properties, the obtained isomers exhibit considerable differences in their anticancer activity and hypoxia selectivity. Conclusion: Substituents and their electronic effects play a key role in the formation of 7- and 6-substituted quinoxaline-2-carbonitrile 1,4-dioxides in the Beirut reaction and in the cytotoxicity properties of the obtained isomers.

A new family of bi-, tetra-, penta-, and hexanickel cagelike phenylsilsesquioxanes 1–6was obtained by self-assembly and transmetalation procedures. Their crystal structures were established by single-crystal X-ray analysis, and features of crystal packing relevant to the network formation were studied by a topological analysis. Compounds 1, 2, and 4are isolated architectures, while 3, 5, and 6present extended 1D and 3D networks. The investigation of magnetic properties revealed the presence of ferro- (1and 3–5) or antiferromagnetic (2and 6) interactions between Ni(II) ions, giving rise in the most cases (1, 2, and 4–6) to the presence of a slow relaxation of the magnetization, which can originate from the spin frustration.

A series of new zinc(II)–thiophene-2,5-dicarboxylate (tdc) MOFs based on novel dodecanuclear wheel-shaped building blocks has been synthesized in almost quantative yields. Single-crystal X-ray diffraction analyses reveal 3D porous frameworks with a complex composition [Zn12(tdc)6(glycolate)6(dabco)3] where glycolate is a deprotonated polyatomic alcohol (ethylene glycol, EgO2, 1; 1,2-propanediol, PrO2, 2; 1,2-butanediol, BuO2, 3; 1,2-pentanediol, PeO2, 4; glycerol, GlO2, 5) and dabco is 1,4-diazo[2.2.2.]bicyclooctane. All compounds 1–5are isostructural except for pendant groups of the diols decorating the surface of channels. The adsorption of small gases (N2, CO2, CH4, C2H2, C2H4, C2H6) and larger hydrocarbons (benzene, cyclohexane) both in liquid and vapor phases was thoroughly investigated for all compounds. The zero-coverage adsorption enthalpies, Henry constants, and selectivity factors by various models are calculated and discussed. The versatile adsorption functionality of the title series results from the variable nature of the diol and could be tailored for a specific adsorbate system. For example, 1shows excellent selectivity of benzene over cyclohexane (20:1 for vapors, 92:1 for liquid phase), while 4demonstrates unprecedented adsorption preference of cyclohexane over benzene (selectivity up to 5:1). The compound 5demonstrates great adsorption selectivity for CO2/N2(up to 75.1), CO2/CH4(up to 7.7), C2H2/CH4(up to 14.2), and C2H4/CH4(up to 9.4). Also, due to polar nature of the pores, 5features size-selective sorption of alkaline metal cations in order Li+> Na+> K+> Cs+as well as a notable luminescent response for cesium(I) ions and urea.

The facile chemical precipitation method and subsequent thermal treatment were shown to be suitable for preparation of crystalline ThO2nanoparticles (NPs) in a wide range of particle sizes (from 2.5 to 34.3 nm). The obtained NPs were investigated with X-ray diffraction, high-resolution transmission electron microscopy, and X-ray absorption techniques to find out the possible size effects associated with nanocrystalline thoria. For 2.5 nm NPs, the lattice parameter of ThO2was found to increase by up to 1.1%, in comparison with the bulk material. The decrease in the particle size was also accompanied by a significant decrease in the Th–Th coordination number.

Unusual high-cluster (Cu9) cage phenylsilsesquioxanes were obtained via complexation of in situ CuII,Na-silsesquioxane species formed with phenanthroline and neocuproine. In the first case, phenanthroline, acting as “a silent ligand” (not participating in the composition of the final product), favors the formation of an unprecedented cagelike phenylsilsesquioxane of Cu9Na6nuclearity, 1. In the second case, neocuproine ligands withdraws two Cu ions from the metallasilsesquioxane matrix, producing two cationic fragments Cu+(neocuproine)2. The remaining metallasilsesquioxane is rearranged into an anionic cage of Cu9Na4nuclearity, finalizing the formation of a specific ionic complex, 2. The impressive molecular architecture of both types of complexes, e.g., the presence of different (cyclic/acyclic) types of silsesquioxane ligands, was established by single-crystal X-ray diffraction studies. Compound 1was revealed to be highly active in the oxidative amidation of benzylic alcohol and the catalyst loading could be reduced down to 100 ppm of Cu. Catalytic studies of compound 1demonstrated its high activity in hydroperoxidation of alkanes with H2O2and oxidation of alcohols to ketones with tert-BuOOH.

A series of three unprecedented heterometallic copper(II) sodium silsesquioxanes were isolated (i) via the unusual rearrangement process during synthesis of coordination polymers or (ii) via the self-assembly reaction using 2,2′-bipyridine. The unique type of these products’ molecular topology consists of an unusual fusion of two sandwich-like components (each including five copper and one sodium sites) via a central copper ion. These compounds correspond to the highest nuclearity among Cu(II)-based cage silsesquioxanes reported to date.

The chemical origin of solvents typically used for preparation of hybrid lead halide perovskites—dimethyl sulfoxide (DMSO), dimethylformamide (DMF), and γ-butyrolactone (GBL)—strongly influences the process of perovskite crystallization because of the formation of intermediate adducts with different structures and morphology. The composition and crystal structures of the adducts depend on the coordination and binding ability of the solvents and the ratio of the precursors. New adducts of perovskite and GBL with either an unusual cluster structure, (MA)8(GBL)x[Pb18I44], or an adduct, (MA)2(GBL)2Pb3I8, similar to those observed for DMF and DMSO are described for the first time. Complex equilibriums between chemical species existing in perovskite solutions are revealed by Raman spectroscopy. As a result, new features of the perovskite crystallization through intermediate adduct phases are discussed, and effective perovskite deposition pathways are suggested.

In this investigation, the synthesis and photophysical properties of a series of new chromophores featuring Pt(II) σ-bonded to perylenediimide (PDI) cores are reported. A Pt(PPh3)2X (X = Cl, Br) moiety was attached to PDI in either the orthoor the bay position (2- or 1-positions respectively) or a Pt(PPh3)2subunit was used to bridge two bay positions (1- and 12-positions) forming a Pt(II) cyclometalate. Through a combination of steady-state and transient absorption and photoluminescence spectroscopy, the excited-state dynamics of these molecules were revealed, indicating that the Pt atom location on the PDI has a substantial impact on observed intersystem crossing (ISC) rates. The ISC time constants for the bay-substituted and cyclometalated PDIs are between 2.67 and 1.29 ns, respectively, determined by the singlet fluorescence decays from the initially populated singlet excited states. In the case of the ortho-substituted PDI, ISC to the triplet state occurs on the ultrafast time scale with a time constant of 345 fs, determined through ultrafast transient absorption spectroscopy. In all instances, the measured PDI-based fluorescence quantum yields quantitatively correlate with the measured ISC rates leaving little doubt that variation in the Pt(II) substitution position(s) markedly influence the resultant photophysics. Electronic structure calculations suggest differing amounts of metal-based contributions in the lowest excited states as a function of substitution position, supporting the trend of the observed ISC rates.

The synthesis, composition, and catalytic properties of a new family of hexanuclear Cu(II)-based phenylsilsesquioxanes are described here. Structural studies of 17 synthesized compounds revealed the general principle underlying their molecular topology: viz., a central metal oxide layer consisting of two Cu3trimers is coordinated by two cyclic [PhSiO1.5]5siloxanolate ligands to form a skewed sandwich architecture with the composition [(PhSiO1.5)10(CuO)6]2+. In addition to this O ligation by the siloxanolate rings, two opposite copper ions are additionally coordinated by the nitrogen atoms of corresponding N ligand(s), such as 2,2′-bipyridine (compounds 1–9), 1,10-phenanthroline (compounds 10–13), mixed 1,10-phenanthroline/2,2′-bipyridine (compound 14), or bathophenanthroline (compounds 15–17). Finally, the charge balance is maintained by two HO–(compounds 1–7, 10–13, and 15–17), two H3CO–(compound 8), or two CH3COO–(compounds 9and 14) anions. Complexes 1and 10exhibited a high activity in the oxidative amidation oxidation of alcohols. Compounds 1, 10, and 15are very efficient homogeneous catalysts in the oxidation of alkanes and alcohols with peroxides.

Uniaxial tension accompanied by the orientation and crystallization of polymer chains is one of the powerful methods for the improvement of mechanical properties. Crystallization of amorphous isotropic polylactide (PLA) at room temperature is studied for the first time during the drawing of films in the presence of liquid adsorption-active media (ethanol, water–ethanol mixtures, and n-heptane) by the solvent crazing mechanism. The crystalline structure arises only under simultaneous actions of a liquid medium and a tensile stress and does not depend on the nature of the environment. The degree of polymer crystallinity increases nearly linearly with the growth in the fraction of the fibrillar material and reaches a maximum value of 42–45%. It has been stated that polymer crystallization happens in crazes involving nanofibrils with a diameter of about 10–20 nm without affecting the bulk polymer parts. Wide-angle X-ray scattering has been used to confirm that the crazing-induced crystallization is accompanied by the formation of the α′-crystalline phase with crystallite sizes (X-ray coherent scattering region) of 3–5 nm, depending on the nature of the liquid medium. After stretching in liquid media to a high tensile strain, the strength of a PLA film has increased to 200 MPa.

We found for the first time a new origin of selection of perovskite crystallization pathways from DMF solutions containing MAI and PbI2to present here a comprehensive study of a full set of essential intermediate phases determining the perovskite’s morphology. For all three discovered structurally different intermediate phases forming at a given precursor ratio, we refined their crystal structures by synchrotron X-ray radiation and investigated dynamics and phase assemblage in the course of decomposition. As a result, we revealed a clear correlation between the composition of the intermediate phases, peculiarities of their crystal structure, and the morphology of the final perovskite films. Using the DFT method we calculated formation enthalpies of these intermediate phases and explained the preferential precipitation of DMSO-adduct rather than DMF-adduct in an antisolvent approach. This finding opens up a possibility of design-on-demand of perovskite materials using simple soft chemistry approaches.

Three types of unusual cagelike copper(II) methylsilsesquioxanes, namely, nona- [(MeSiO1.5)18(CuO)9] 1, hexa- [(MeSiO1.5)10(HO0.5)2(CuO)6(C12H8N2)2(MeSiO1.5)10(HO0.5)1.33(CH3COO0.5)0.67(CuO)6(C12H8N2)2] 2, [(MeSiO1.5)10(CuO)6(MeO0.5)2(C10H8N2)2] 3, and trinuclear [(MeSiO1.5)8(CuO)3(C10H8N2)2] 4, were obtained in 44%, 27%, 20%, and 16% yields, respectively. Nuclearity and structural fashion of products was controlled by the choice of solvent system and ligand, specifically assisting the assembling of cage. Structures of 1–4were determined by single-crystal X-ray diffraction analysis. Compounds 1and 4are the first cage metallasilsesquioxanes, containing nine and three Cu ions, respectively. Product 1is the first observation of nonanuclear metallasilsesquioxane ever. Unique architecture of 4represents early unknown type of molecular geometry, based on two condensed pentamembered siloxane cycles. Topological analysis of metal clusters in products 1–4is provided. Complex 1efficiently catalyzes oxidation of alcohols with tert-butylhydroperoxide TBHP to ketones or alkanes with H2O2to alkyl hydroperoxides in acetonitrile.

C21H25NO8, P21/n, (no. 14), a= 12.905(3) Å, b= 13.370(3) Å, c= 13.090(3) Å, β= 118.19(3)°, V= 1990.5(8) Å3, Z= 4, Rgt(F) = 0.0629, wRref(F2) = 0.1966, T= 100(2) K.

The series of bimetallic complexes (tBuPXCYP)Pd(μ-OC)M(CO)2L (X, Y = CH2, O; M = W, Mo; L = Cp, Tp) catalyzes formic acid decomposition into H2/CO2in fairly mild conditions (25–50 °C, toluene) without any organic base additives. The catalytic activity of bimetallic complexes increases with CH2-substitution of the O-bridges in the (PXCYP)-frame as well as with the proton-donating ability of the Mo/W hydride. The best result was obtained with (tBuPCP)Pd(μ-OC)Mo(CO)2Cp (3), which gives complete conversion at 2 mol % loading in 30 min at 50 °C (TOF = 100 h–1). During the catalysis, LM(CO)3H and (tBuPXCYP)Pd(OCHO) form as visible intermediates, while the palladium hydride species are also involved in the catalytic cycle. The experimental data show that hydride abstraction/CO2release from palladium formates (tBuPXCYP)Pd(OCHO) is assisted by −OCHO···H–A hydrogen bonding with excess formic acid or acidic hydride LM(CO)3H. These findings highlight the pivotal role of the formate interaction with Brönsted or Lewis acids at the hydride abstraction/CO2release step and unify the mechanisms suggested for different catalytic systems.

A highly efficient synthetic approach was developed for the synthesis of unsymmetrical 1,10-phenanthroline-2,9-diamides with two different substituents in the fourth and seventh positions of the phenanthroline core. The structures of these ligands were confirmed using various spectral methods including 2D-NMR and X-ray analysis. Quantum chemical calculations supported the presence of tautomeric forms of these ligands. Furthermore, it was discovered that these compounds exhibit polydentate ligand behavior toward lanthanide nitrates. The structural characteristics of the complexes formed between these ligands and lanthanide nitrates were investigated both in the solid state and in solution. To further understand the binding properties of these novel unsymmetrical ligands, the binding constants for potential complexes were quantitatively measured by using UV–vis spectrophotometric titration. This allowed for a comprehensive analysis of the binding affinity and stability of these complexes. Extraction experiments of f-elements were performed for symmetrical and unsymmetrical diamides. Overall, this study presents significant advancement in the synthesis and characterization of unsymmetrical 1,10-phenanthroline-2,9-diamides and provides valuable insights into their potential applications as polydentate ligands for lanthanide nitrates.

C16H16O7, monoclinic, P21/n(no. 14), a= 12.830(3) Å, b= 8.1101(16) Å, c= 14.900(3) Å, β= 114.88(3)°, V= 1406.5(6) Å3, Z= 4, Rgt(F) = 0.0578, wRref(F2) = 0.1799, T= 100(2) K.

The present study describes a new feature in the self-assembly of cagelike copperphenylsilsesquioxanes: the strong influence of acetone solvates on cage structure formation. By this simple approach, a series of novel tetra-, hexa-, or nonacoppersilsesquioxanes were isolated and characterized. In addition, several new complexes of Cu4or Cu6nuclearity bearing additional nitrogen-based ligands (ethylenediamine, 2,2′-bipyridine, phenanthroline, bathophenanthroline, or neocuproine) were produced. Single-crystal X-ray diffraction studies established molecular architectures of all of the synthesized products. Several coppersilsesquioxanes represent a novel feature of cagelike metallasilsesquioxane (CLMS) in terms of molecular topology. A Cu4–silsesquioxane complex with ethylenediamine (En) ligands was isolated via the unprecedented self-assembly of a partly condensed framework of silsesquioxane ligands, followed by the formation of a sandwich-like cage. Two prismatic Cu6complexes represent the different conformers─regular and elliptical hexagonal prisms, “cylinders”, determined by the different orientations of the coordinated acetone ligands (“shape-switcheffect”). A heterometallic Cu4Na4-sandwich-like derivative represents the first example of a metallasilsesquioxane complex with diacetone alcohol ligands formed in situ due to acetone condensation reaction. As a selected example, the compound [(Ph6Si6O11)2Cu4En2]·(acetone)2was explored in homogeneous oxidation catalysis. It catalyzes the oxidation of alkanes to alkyl hydroperoxides with hydrogen peroxide and the oxidation of alcohols to ketones with tert-butyl hydroperoxide. Radical species take part in the oxidation of alkanes. Besides, [(Ph6Si6O11)2Cu4En2]·(acetone)2catalyzes the mild oxidative functionalization of gaseous alkanes (ethane, propane, n-butane, and i-butane). Two different model reactions were investigated: (1) the oxidation of gaseous alkanes with hydrogen peroxide to give a mixture of oxygenates (alcohols, ketones, or aldehydes) and (2) the carboxylation of Cngaseous alkanes with carbon monoxide, water, and potassium peroxodisulfate to give Cn+1carboxylic acids (main products), along with the corresponding Cnoxygenates. For these reactions, the effects of acid promoter, reaction time, and substrate scope were explored. As expected for free-radical-type reactions, the alkane reactivity follows the trend C2H6< C3H8< n-C4H10< i-C4H10. The highest total product yields were observed in the carboxylation of i-butane (up to 61% based on i-C4H10). The product yields and catalyst turnover numbers (TONs) are remarkable, given an inertness of gaseous alkanes and very mild reaction conditions applied (low pressures, 50–60 °C temperatures).

This study presents a methodology for the synthesis of the ionic cyclopropenium-derived triplatinum cluster complex [(Ph3C3)2Pt3(MeCN)4]2+(BF4–)2and its analogue with the replacement of one of the BF4–anions with a Cl–anion, which represents a chain coordination polymer in crystalline form. The structures of the complexes were studied by several physicochemical methods, primarily X-ray diffraction using synchrotron radiation and 195Pt NMR spectroscopy in solution with measurement and analysis of the 195Pt–195Pt and 13C–195Pt spin–spin coupling constants. In addition, a high catalytic activity of the synthesized Pt3complex was observed in hydrosilylation reactions. The catalytic efficiency of the complex was found to be comparable to that of Karstedt’s catalyst and in some cases even higher.