Organic Substituents Research Articles

New type of RNA virus replication inhibitor based on decahydro-closo-decaborate anion containing amino acid ester pendant group.

In this work, a synthetic approach to prepare an example of new class of the derivatives of the closo-decaborate anion with amino acids detached from the boron cluster by pendant group has been proposed and implemented. Compound Na2[B10H9–O(CH2)4C(O)–His–OMe] was isolated and characterized. This compound has an inorganic hydrophobic core which is the 10-vertex boron cage and the –O(CH2)4C(O)–His–OMe organic substituent. It has been shown to possess strong antiviral activity in vitro against modern strains of A/H1N1 virus at 10 and 5 µg/mL. The compound has been found to be non-cytotoxic up to 160 µg/mL. At the same time, the compound has been found to be inactive against SARS-CoV-2, indicating specific activity against RNA virus replication. Molecular docking of the target derivative of the closo-decaborate anion with a model of the transmembrane region of the M2 protein has been performed and the mechanism of its antiviral action is discussed.Graphical Supplementary InformationThe online version contains supplementary material available at 10.1007/s00775-022-01937-4.

Formation of Self-organized Structures of Hybrid Amorphous Materials Based on Polyhedral Silsesquioxanes

The formation of self-organized structures of organic-inorganic hybrid amorphous molecules based on polyhedral silsesquioxanes (POSS) is reported. The hybrid materials were synthesized using POSS as the inorganic core and cyanobiphenyl (CBP) as the organic substituent. The type of structure formed depends on the length of the alkyl spacer used to connect the POSS and CBP groups. The hybrid amorphous material with an alkyl spacer consisting of eleven methylene units resulted in Voronoi-like dot patterns, the size of which are easily controlled by varying the thickness of the initial films.

The physiology and metabolic properties of a novel, low-abundance Psychrilyobacter species isolated from the anoxic Black Sea shed light on its ecological role.

Members of the Psychrilyobacter spp. of the phylum Fusobacteria have been recently suggested to be amongst the most significant primary degraders of the detrital organic matter in sulfidic marine habitats, despite representing only a small proportion (<0.1%) of the microbial community. In this study, we have isolated a previously uncultured Psychrilyobacter species (strains SD5T and BL5; Psychrilyobacter piezotolerans sp. nov.) from the sulfidic waters (i.e., 2000 m depth) of the Black Sea and investigated its physiology and genomic capability in order to better understand potential ecological adaptation strategies. P. piezotolerans utilized a broad range of organic substituents (carbohydrates and proteins) and, remarkably, grew at sulfide concentrations up to 32 mM. These flexible physiological properties were supported by the presence of the respective metabolic pathways in the genomes of both strains. Growth at varying hydrostatic pressure (0.1-50 MPa) was sustained by modifying its membrane lipid composition. Thus, we have isolated a novel member of the 'rare biosphere', which endures the extreme conditions and may play a significant role in the degradation of detrital organic matter sinking into the sulfidic waters of the Black Sea.

From the {FeIII 2 Ln2 } Butterfly's Perspective: the Magnetic Benefits and Challenges of Cooperativity within 3 d-4 f Based Coordination Clusters.

In this Review we discuss the tuning handles which can be used to steer the magnetic properties of FeIII‐4 f “butterfly” compounds. The majority of presented compounds were produced in the context of project A3 “Di‐ to tetranuclear compounds incorporating highly anisotropic paramagnetic metal ions” within the SFB/TRR88 “3MET”. These contain {FeIII 2Ln2} cores encapsulated in ligand shells which are easy to tune in a “test‐bed” system. We identify the following advantages and variables in such systems: (i) the complexes are structurally simple usually with one crystallographically independent FeIII and LnIII, respectively. This simplifies theory and anaylsis; (ii) choosing Fe allows 57Fe Mössbauer spectroscopy to be used as an additional technique which can give information about oxidation levels and spin states, local moments at the iron nuclei and spin‐relaxation and, more importantly, about the anisotropy not only of the studied isotope, but also of elements interacting with this isotope; (iii) isostructural analogues with all the available (i. e. not Pm) 4 f ions can be synthesised, enabling a systematic survey of the influence of the 4 f ion on the electronic structure; (iv) this cluster type is obtained by reacting [FeIII 3O(O2CR)6(L)3](X) (X=anion, L=solvent such as H2O, py) with an ethanolamine‐based ligand L′ and lanthanide salts. This allows to study analogues of [FeIII 2Ln2(μ3‐OH)2(L′)2(O2CR)6] using the appropriate iron trinuclear starting materials. (v) the organic main ligand can be readily functionalised, facilitating a systematic investigation of the effect of organic substituents on the ligands on the magnetic properties of the complexes. We describe and discuss 34 {MIII 2Ln2} (M=Fe or in one case Al) butterfly compounds which have been reported up to 2020. The analysis of these gives perspectives for designing new SMM systems with specific electronic and magnetic signatures

Amorphous Molecular Materials for Directed Supercontinuum Generation

AbstractMolecular compounds of the general formula [(RT)4E6] (R=organic or organometallic substituent; T=C, Si, Ge, Sn; E=CH2, S, Se), hence adamantane derivatives and inorganic‐organic hybrid compounds based on a heteroadamantane structure exhibit a non‐linear optical response upon radiation with a continuous‐wave near‐infrared laser. The effect depends on the compounds’ habitus, which itself depends on the elemental composition of the cluster core, and on the nature of the organic substituents. A combination of these parameters that cause the material to be intrinsically amorphous leads to supercontinuum generation and thus to the emission of a broad spectrum, potentially appearing as white light. Notably, the emission essentially retains the driving laser's directionality. For crystalline samples, second harmonic generation is observed instead, which points to a close relationship of the optical properties and the intermolecular order. Variation of R, T, and E allows further fine‐tuning of the emitted spectra. We present all studies made in regards to these effects and our overarching conclusions derived from them.

Generation of non-stabilized alkyl radicals from thianthrenium salts for C\u2013B and C\u2013C bond formation

Sulfonium salts bearing a positively charged sulfur atom with three organic substituents have intrigued chemists for more than a century for their unusual structures and high chemical reactivity. These compounds are known to undergo facile single-electron reduction to emerge as a valuable and alternative source of aryl radicals for organic synthesis. However, the generation of non-stabilized alkyl radicals from sulfonium salts has been a challenge for several decades. Here we report the treatment of S-(alkyl) thianthrenium salts to generate non-stabilized alkyl radicals as key intermediates granting the controlled and selective outcome of the ensuing reactions under mild photoredox conditions. The value of these reagents has been demonstrated through the efficient construction of alkylboronates and other transformations, including heteroarylation, alkylation, alkenylation, and alkynylation. The developed method is practical, and provides the opportunity to convert C–OH bond to C–B and C–C bonds.

Study of the impurities in technical-grade 1,3,5-trimethyl-1,3,5-triphenylcyclotrisiloxane by gas chromatography-mass spectrometry

Polymerization of 1,3,5-trimethyl-1,3,5-triphenylcyclotrisiloxane is the main method for manufacturing methylphenylsiloxane rubbers, and copolymerization of octamethylcyclotetrasiloxane and 1,3,5-trimethyl-1,3,5-triphenylcyclotrisiloxane is the main method for production of high- and low-molecular weight dimethylmethylphenylsiloxane rubbers. The molecular weight, viscosity, and other properties of the obtained polymers depend on the purity of cyclosiloxanes. The technology of 1,3,5-trimethyl-1,3,5-triphenylcyclotrisiloxane production by thermocatalytic decomposition of methylphenylsiloxanes in the presence of lithium hydroxide or lithium silanolate, followed by vacuum rectification, makes it possible to obtain a product containing 1,3,5,7-tetramethyl-1,3,5,7-tetraphenylcyclotetrasiloxanes, tetraphenyldimethyldisiloxane as impurities and trace amounts of phenyl-containing siloxanes of cyclic and linear structure. The impurities of polycyclic and polyhedral structures have not been previously described. In this study, the method of gas chromatography-mass spectrometry is used to analyze compounds that can be present as impurities in technical-grade 1,3,5-trimethyl-1,3,5-triphenylcyclotrisiloxane. The use of the previously described regularities of the fragmentation of siloxanes of different structures made it possible to identify a number of siloxanes which are absent in the NIST 11 mass spectra library. It is shown that polycyclic and polyhedral compounds containing methylsilsesquioxane units have a short fragmentation path. They are characterized by ionization with the elimination of the methyl group and benzene in case of two phenyl groups in the molecule. The siloxane skeleton of such cations is rather stable, so they more readily lose another methyl group thus transforming into double-charged cations. The impact of electron ionization on the molecules with siloxane units containing different organic substituents at silicon leads to randomization of those substituents and rearrangement of the siloxane skeleton. Analysis of the results revealed that silanes, siloxanes of linear, cyclic, polycyclic and polyhedral structures are present in technical grade 1,3,5-trimethyl-1,3,5-triphenylcyclotrisiloxane.

Highly Soluble Supertetrahedra upon Selective Partial Butylation of Chalcogenido Metalate Clusters in Ionic Liquids

AbstractSupertetrahedral clusters have been reported in two generally different types so far: one type possessing an organic ligand shell, no or low charges, and high solubility, while the other cluster type is ligand‐free with usually high charges and low or no solubility in common solvents. The latter is a tremendous disadvantage regarding further use of the clusters in solution. However, as organic substituents usually broaden the HOMO–LUMO gaps, which cannot be overcompensated by the (limited) cluster sizes, a full organic shielding comes along with drawbacks regarding opto‐electronic properties. We therefore sought to find a way of generating soluble clusters with a minimum number of organic substituents. Here, we present the synthesis and full characterization of two salts of [Sn10O4S16(SBu)4]4− that are high soluble in CH2Cl2 or CH3CN, which includes first NMR and mass spectra obtained from solutions of such salts with mostly inorganic supertetrahedral clusters. The optical absorption properties of this new class of compounds indicates nearly unaffected band gaps. The synthetic approach and the spectroscopic findings were rationalized and explained by means of high‐level quantum chemical studies.

Hybrid Xerogels: Study of the Sol-Gel Process and Local Structure by Vibrational Spectroscopy.

The properties of hybrid silica xerogels obtained by the sol-gel method are highly dependent on the precursor and the synthesis conditions. This study examines the influence of organic substituents of the precursor on the sol-gel process and determines the structure of the final materials in xerogels containing tetraethyl orthosilicate (TEOS) and alkyltriethoxysilane or chloroalkyltriethoxysilane at different molar percentages (RTEOS and ClRTEOS, R = methyl [M], ethyl [E], or propyl [P]). The intermolecular forces exerted by the organic moiety and the chlorine atom of the precursors were elucidated by comparing the sol-gel process between alkyl and chloroalkyl series. The microstructure of the resulting xerogels was explored in a structural theoretical study using Fourier transformed infrared spectroscopy and deconvolution methods, revealing the distribution of (SiO)4 and (SiO)6 rings in the silicon matrix of the hybrid xerogels. The results demonstrate that the alkyl chain and the chlorine atom of the precursor in these materials determines their inductive and steric effects on the sol-gel process and, therefore, their gelation times. Furthermore, the distribution of (SiO)4 and (SiO)6 rings was found to be consistent with the data from the X-ray diffraction spectra, which confirm that the local periodicity associated with four-fold rings increases with higher percentage of precursor. Both the sol-gel process and the ordered domains formed determine the final structure of these hybrid materials and, therefore, their properties and potential applications.

Deep-red circularly polarised luminescent C70 derivatives

Optically active fullerenes, including C60 and C70 derivatives carrying organic substituents, are used in a range of applications because of their unique spectroscopic, catalytic, and chiral recognition properties. However, their inherent photoexcited chirality is yet to be elucidated because of their very poor fluorescence quantum yield (Φf). We synthesised a new chiral C70 derivative, X70A, with 20% yield, by reacting bis-borylated xanthene with C70 in a one-step double addition reaction, followed by a successful optical resolution. The isolation of two separate X70A enantiomers was confirmed by mirror-image circular dichroism spectroscopy in the range of 300–750 nm. In toluene, the enantiomeric pair of X70A clearly revealed mirror-image circularly polarised luminescence (CPL) spectra with a high |glum| value of 7.0 × 10−3 at 690 nm. The first fullerene-based deep-red CPL of X70A should provide a new guideline for the design of chiral nanocarbon materials.

Synthesis of Tetrahedranes Containing the Unique Bridging Hetero-Dipnictogen Ligand EE' (E ≠ E'=P, As, Sb, Bi).

In order to improve and extend the rare class of tetrahedral mixed main group transition metal compounds, a new synthetic route for the complexes [{CpMo(CO)2}2(μ,η2:η2‐PE)] (E=As (1), Sb (2)) is described leading to higher yields and a decrease in reaction steps. Via this route, also the so far unknown heavier analogues containing AsSb (3 a), AsBi (4) and SbBi (5) ligands, respectively, are accessible. Single crystal X‐ray diffraction experiments and DFT calculations reveal that they represent very rare examples of compounds comprising covalent bonds between two different heavy pnictogen atoms, which show multiple bond character and are stabilised without any organic substituents. A simple one‐pot reaction of [CpMo(CO)2]2 with ME(SiMe3)2 (M=Li, K; E=P, As, Sb, Bi) and the subsequent addition of PCl3, AsCl3, SbCl3 or BiCl3, respectively, give the complexes 1–5. This synthesis is also transferable to the already known homo‐dipnictogen complexes [{CpMo(CO)2}2(μ,η2:η2‐E2)] (E=P, As, Sb, Bi) resulting in higher yields comparable to those in the literature reported procedures and allows the introduction of the bulkier and better soluble Cp′ (Cp′=tert butylcyclopentadienyl) ligand.

Coordination Properties of Non-Rigid Phosphinoyldithioformate Complexes of the [Mo2O2(µ-S)2]2+ Cation in Catalytic Sulfur Transfer Reactions with Thiiranes

Two “Mo2O2S2”-based complexes with phosphinoyldithioformate ligands were synthesized from the metathesis reaction of [R2P(O)CS2]− with (Me4N)2[Mo2O2(µ-S)2(Cl)4] to give [Mo2O2(µ-S)2{R2P(O)CS2}2] (1; R = Ph, 2; R = Bn). The complexes were fully characterized, including the X-ray crystal structure for 1. Variable temperatures 31P NMR of 1 and 2 exhibit non-rigid behavior in solution where three and two coordination isomers were present, respectively. The organic substituent on the P atom greatly impacts the complex non-rigid properties and behavior. The catalytic activity of 1 and 2 towards sulfur atom transfer (SAT) using propylene sulfide and cyclohexene sulfide was explored, employing homogeneous reaction conditions at an ambient temperature on the NMR scale. The complexes showed distinctly different properties along with high conversions in short reaction times. A catalytic cycle consistent with the results is proposed.

Arylarsonate- and Phosphonate-Capped Polyoxomolybdates, [(RC6H4As)2Mo6O24]n− and [(R′C6H4P)2Mo5O21]n−

We report on the synthesis and structural characterization of four arylarsonate- and phosphonate-capped polyoxomolybdates that exhibit different organic substituents in the para position of the phenyl group. The reaction of arylarsonates (RAsO3, wherein R = 4-BrC6H4 or 4-N3C6H4) with molybdate in aqueous pH 3.5 media resulted in the cyclic hexamolybdates [(BrC6H4As)2Mo6O24]4- (Mo6As2La) and [(N3C6H4As)2Mo6O24]4- (Mo6As2Lb), whereas the reaction of arylphosphonates (R'PO3, wherein R' = 4-O2CC6H4 or 4-O2CC6H4CH2) with molybdate in aqueous pH 3 media resulted in the cyclic pentamolybdates [(O2CC6H4P)2Mo5O21]6- (Mo5P2Lc) and [(HO2CC6H4CH2P)2Mo5O21]4- (Mo5P2Ld), respectively. Polyanions Mo6As2La and Mo6As2Lb comprise a ring of six MoO6 octahedra that is capped on either side by an organoarsonate group, whereas Mo5P2Lc and Mo5P2Ld consist of a ring of five MoO6 octahedra that is capped on either side by an organophosphonate group, with the organic arms protruding away from the metal-oxo core of the polyanions. All four polyanions Mo6As2La, Mo6As2Lb, Mo5P2Lc, and Mo5P2Ld have been characterized in the solid state by single-crystal X-ray diffraction, IR spectroscopy, and thermogravimetric and elemental analysis and in solution by multinuclear NMR (31P, 13C, and 1H). The synthetic procedure of (4-bromophenyl)arsonic acid, BrC6H4AsO3H2, is reported here for the first time.

Synthesis and characterization of linear multi-functional phosphazene structures for polymer cross-linking

Phosphazenes are a well-studied class of organometallic compounds with perspective characteristics, already tested in various applications. However, until now, three-dimensionally crosslinked structures based on them are primarily obtained by irradiation (that is UV and Cobalt-60). It is generally accepted that such processes proceed via the mechanism of the cleavage of C-H bonds present in the organic substituents, which clearly indicates the lack of selectivity and the impossibility to control the crosslinking degree and distribution. Within this article, multifunctional organosubstituted structures based on the short-chain penta-functional trichlorophosphazodichlorophosphonyl with eugenol and methacrylic fragments were obtained. All products were characterized by1H and31P NMR spectroscopy and MALDI-TOF mass spectrometry. The tendency of compounds with linear methacrylic substituents to undergo the phosphazene-phosphazane rearrangement, so that the dominant reaction product turns to the tetrasubstituted derivative, has been shown. All the obtained compounds can be used as the independent monomers to obtain rigid hybrid organo-inorganic matrices, as well as polyfunctional crosslinking agents for various polymers.

Study of Crystallization and Composition on Silicon Oxycarbide (SiOC) and Silicon Boron Oxycarbide (SiBOC) Ceramics Obtained from Alkoxysilanes Precursors

This work deals on the preparation of silicon oxycarbide (SiOC) and silicon boron oxycarbide (SiBOC) ceramics from pyrolysis involving alkoxysilanes with different organic groups. Boron content, organic substituent and annealing time were evaluated on crystallization and composition of resulting ceramics. B-free precursors composed of methyltriethoxysilane (MTES), phenyltriethoxysilane (PTES) and vinyltrimethoxysilane (VTMS) were obtained by the sol-gel method, whilst B-containing precursors were prepared by adding to each alkoxysilane a proper amount of boric acid resulting in B/Si atomic ratios of 0.1 and 0.5. Precursors were pyrolyzed at 1500 °C for 1 and 3 h to produce respective SiOC and SiBOC ceramics. X-ray diffraction (XRD) patterns revealed enhanced SiC phase crystallization for PTES-derived ceramics, followed by those containing vinyl and methyl groups, which was also confirmed by X-ray photoelectron spectroscopy (XPS) from percentages of Si-C and Si-O bonds. Csp2 and Csp3 amounts varied among ceramics, indicating direct influence of organic substituent on conductive carbon phase development. Boron addition induced the growth of SiC crystallites, having more evident effect in matrices with higher proportions of amorphous fraction and lower residual carbon amounts. Organic group nature, boron content and annealing time played an important role for production and evolution of SiC and C phases into ceramics.

Theoretical Study to Predict the Ability to Use Different Organic Substituents as Carrier Linkages for Diclofenac

The research includes unrestricted (UDFT) and (UPM3) quantum mechanical calculations for studying the reaction path of bonds rupture energies of (O-R) and (C-OAr) in twelve diclofenac derivatives containing different substituted organic groups. All the calculations were performed at the optimize geometries in vacuum phase by using Gaussian 09 program. Comparison was done between the studied diclofenac derivatives and the standard ionic diclofenac of sodium and potassium included geometrical structures, physical properties, total energies of the reactants and products, activation energies and transition states. The results showed that some substituted organic groups could be used to form good carrier bonds for the acidic drug diclofenac, while others were less efficient depending on the nature of the substituted carrier, and that there is a preference for carriers of the type (–R) over the carriers of the type (–Ar).

Synthesis of Boron Analogues of Enamines via Hydroamination of a Boron-Boron Triple Bond.

An N‐heterocyclic‐carbene‐stabilized diboryne undergoes rapid, high‐yielding and catalyst‐free hydroamination reactions with primary amines, yielding 1‐amino‐2‐hydrodiborenes, which can be considered boron analogues of enamines. The electronics of the organic substituent at nitrogen influence the structure and further reactivity of the diborene product. With electron‐rich anilines, a second hydroamination can occur at the diborene to generate 1,1‐diamino‐2,2‐dihydrodiboranes. With isopropylamine, the electronic influence of the alkyl substituent upon the diborene leads to an unprecedented boron‐mediated intramolecular N‐dearylation reaction of an N‐heterocyclic carbene unit.

Conversion of dimethyl ether to liquid hydrocarbons on zeolite catalysts: Influence of a base admixture in the zeolite

This paper presents comparative data on the selectivity and gasoline fraction composition for commercial catalysts based on Zn- and Pd-modified zeolites with the same MFI structural type, but produced by different manufacturers. The data are obtained in the operation of a two-reactor micropilot unit in a flow circulation mode. The relationship and differences between the character and type of Brønsted acid site were investigated using in situ high-temperature diffuse reflectance IR spectroscopy during annealing of the catalysts in dry argon, hydrogen, and dimethyl ether flows. It was found that catalysts contain organic ammonium cations with different structures of organic substituents, which decompose to give a very strong nitrogen-containing acid site. This site can promote the formation of branched paraffins and light aromatics from dimethyl ether. Under the action of these sites, methanol can be rapidly converted to DME, which is more reactive towards the production of gasoline fraction.

Synthesis of high surface area aluminophosphate and -phosphonate xerogels by non-hydrolytic sol-gel reactions

We disclose the preparation of high-surface-area mesoporous aluminophosphates and aluminophosphonates by the non-hydrolytic sol-gel reactions (NHSG) of Al(NMe 2 ) 3 with trimethylsilylated phosphate OP(OSiMe 3 ) 3 , phosphonates RP(O)(OSiMe 3 ) 2 (R = Me, t Bu, Ph), and bis-phosphonates (Me 3 SiO) 2 (O)P–X–P(O)(OSiMe 3 ) 2 (X = C 6 H 4 , (C 6 H 4 ) 2 ) in dry toluene. The reactions proceed by silylamine elimination of Me 3 SiNMe 2 to provide organic-inorganic hybrid xerogels with properties influenced by organic substituents and the Al:P ratio of the precursors. Dried xerogels exhibit large surface areas (up to 1000 m 2 g −1 ) and matrices based on condensed Al–O–P networks. They stay stable under relatively harsh thermal conditions. 27 Al, 13 C, and 29 Si solid-state NMR spectroscopy was employed to characterize the aluminum coordination and the residual amido and trimethylsilyl groups. The catalytic performance of NHSG prepared material was examined in gas-phase dehydration of ethanol to ethylene exhibiting conversion and selectivity comparable to weak solid acid benchmark catalysts. The number of unreacted surface groups was determined by gravimetric measurements and by thermal analysis (TG-DSC). These residual groups have the potential to be used in post-synthetic grafting of catalytically active metal centers. • Aluminophosphates and aluminophosphonates are prepared by non-hydrolytic sol-gel synthesis. • Mesoporous xerogels with large surface areas (1030 m 2 g -1 ). • Gas-phase dehydration of ethanol to ethylene with good conversion and selectivity.

Criteria pollutant impacts of volatile chemical products informed by near-field modeling.

Consumer, industrial, and commercial product usage is a source of exposure to potentially hazardous chemicals. In addition, cleaning agents, personal care products, coatings, and other volatile chemical products (VCPs), evaporate and react in the atmosphere producing secondary pollutants. Here, we show high air emissions from VCP usage (≥ 14 kg person−1 yr−1, at least 1.7× higher than current operational estimates) are supported by multiple estimation methods and constraints imposed by ambient levels of ozone, hydroxyl radical (OH) reactivity, and the organic component of fine particulate matter (PM2.5) in Pasadena, California. A near-field model, which estimates human chemical exposure during or in the vicinity of product use, indicates these high air emissions are consistent with organic product usage up to ~75 kg person−1 yr−1, and inhalation of consumer products could be a non-negligible exposure pathway. After constraining the PM2.5 yield to 5% by mass, VCPs produce ~41% of the photochemical organic PM2.5 (1.1 ± 0.3 μg m−3) and ~17% of maximum daily 8-hr average ozone (9 ± 2 ppb) in summer Los Angeles. Therefore, both toxicity and ambient criteria pollutant formation should be considered when organic substituents are developed for VCPs in pursuit of safer and sustainable products and cleaner air.