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Methane (CH4) can be captured in silico with a light atom molecule containing only C, H, Si, O, and B atoms, respectively. A tripodal peri-substituted ligand system was employed, namely, [(5-Ph2B-xan-4-)3Si]H (1, xan = xanthene), which after hydride abstraction (1+) carries four Lewis acidic sites within the cationic cage structure. In a previous study, this system was shown to be able to capture noble gas atoms He–Kr (Mebs & Beckmann 2022). In the corresponding methane complex, 1+CH4, a polarized Si+⋯CH4 contact of 2.289 Å as well as series of (H3)CH⋯O/CPh hydrogen bonds enforce spatial CH4 fixation (the molecule obeys C3-symmetry) and slight activation. A trigonal-pyramidal Si–CHeq3–Hax local geometry is thereby approached with Hax–C–Heq angles decreased to 103.7°. All attempts to replace the Lews acidic –BPh2 fragments in 1 with basic –PR2 (R = Ph, tBu) fragments indeed increased intra-molecular hydrogen bonding between host molecule and CH4, and thus caused stronger activation of the latter, however ultimately resulted in the formation of energetically favorable quenched structures with short P–Si contacts, making CH4 binding hard to achieve. The electronic situation of two hypothetic methane complexes, 1+CH4 and [(5-tBu2P-xan-4-)3SiCH4]+ (2+CH4), was determined by a set of calculated real-space bonding indicators (RSBIs) including the Atoms-In-Molecules (AIM), non-covalent interactions index (NCI), and electron localizability indicator (ELI-D) methods, highlighting crucial differences in the level of activation. The proposed ligand systems serve as blueprints for a more general structural design with adjustable trigonal ligand systems in which central atom, spacer fragment, and functional peri-partner can be varied to facilitate different chemical tasks.

The Si–H bond in {(F3C)3CO}3SiH is exceptionally strong and short; yet the acidity is comparable to common organic acids. This apparent contradiction will be discussed with the aid of contemporary DFT methods.

The first essentially three-coordinated plumbylium cation [RindMe2Pb]+ was obtained with the aid of a bulky and rigid Rind substituent (Rind = dispiro[fluorene-9,3′-(1′,1′,7′,7′-tetramethyl-s-hydrindacen-4′-yl)-5′,9′′-fluorene).

Despite noteworthy charge transfer and numerous intermolecular interactions, the title complexes (chalcogen = S, Se and Te) are weakly bonded; the most important contributions to the interaction energy are of dispersion and electrostatic nature.

Intermolecular interactions of the new drug candidate sila-ibuprofen are investigated in the crystal and in the enzyme cyclooxygenase-II., Sila-ibuprofen is a new potential nonsteroidal anti-inflammatory drug which deviates from its parent ibuprofen in terms of the electrostatic potential around the carbon/silicon-switched C/Si—H group. Therefore, sila-ibuprofen is more water soluble and has a lower melting enthalpy. However, its binding and inhibition properties of cyclooxygenases appear to be very similar to regular ibuprofen. Therefore, in this study, intermolecular interactions and interaction densities of both ibuprofen and sila-ibuprofen in their biologically active forms, i.e. deprotonated and as the pure S-enantiomers are investigated. Quantum-crystallographically refined salts with argininium and 1-phenyl­ethan-1-amoninium (PEA) counter-cations as crystalline models of the interactions with the guanidine functional group of arginine inside cyclooxygenases are presented. The similarities and differences between the polarization of ibuprofen and sila-ibuprofen in the crystal, enzyme, solvent and isolated environments are discussed based on quantum-chemical calculations. For the explicit crystal and enzyme environments, specifically, molecular dynamics simulations starting from the crystal models were combined with QM/MM calculations.

Sterically encumbered bis(m-terphenyl)chalcogenides, (2,6-Mes2C6H3)E (E = S, Se, Te) were obtained by the reaction of the chalcogen tetrafluorides, EF4, with three equivalents of m-terphenyl lithium, 2,6-Mes2C6H3Li. The single electron oxidation of (2,6-Mes2C6H3)2Te using XeF2 / K[B(C6F5)4] afforded the radical cation [(2,6-Mes2C6H3)2Te][B(C6F5)4] that was isolated and fully characterized. The electrochemical oxidation of the lighter homologs (2,6-Mes2C6H3)2E (E = S, Se) was irreversible and impaired by rapid decomposition.

The reaction of (5-Ph2P-Ace-6-)Li (I) with InCl3 provided (6-Ph2P-Ace-5-)3In (1), which proved to be a remarkably mild transmetalation reagent. The reaction of 1 with NiCl2, originally aimed to all...

Protocols for the synthesis of the bulky polyfluorinated triarylboranes 2,6‐(C6F5)2C6F3B(C6F5)2 (1), 2,6‐(C6F5)2C6F3B[3,5‐(CF3)2C6H3] (2), 2,4,6‐(C6F5)3C6H2B(C6F5)2 (3), 2,4,6‐(C6F5)3C6H2B[3,5‐(CF3)2C6H3] (4) were developed. All boranes are water tolerant and according to the Gutmann‐Beckett method, 1–3 display Lewis acidities larger than that of the prominent B(C6F5)3., Water tolerant boranes: The synthesis and characterization of bulky polyfluorinated triarylboranes 2,6‐(C6F5)2C6F3B(C6F5)2 (1), 2,6‐(C6F5)2C6F3B[3,5‐(CF3)2C6H3] (2), 2,4,6‐(C6F5)3C6H2B(C6F5)2 (3), 2,4,6‐(C6F5)3C6H2B[3,5‐(CF3)2C6H3] (4) is presented. Unlike the prominent B(C6F5) („BCF“), 1–4 are water tolerant and 1–3 even show larger Lewis acidities, as determined by the Gutmann‐Beckett method.

2-Methyl-9H-thioxanthene-9-one (1) and its S,S-dioxide (2) are the precursors of pendant groups that determine the reduction potentials of electro-active polyimides, which exhibit electrochromic behavior and are used in organic electronics. Electrochemical reduction of 1 and 2 leads to the formation of the corresponding persistent radical anions and dianion (for S,S-dioxide). Using 3D spectroelectrochemistry, all anions have been shown to exhibit strong absorption in the UV-VIS-NIR wavelength region. Electronic absorption spectra of 1 and 2 and their negative ions were interpreted using time-dependent DFT. According to the calculations, the most intense electronic transitions of the dianions 12 and 22- in the visible region exhibit hypsochromic shift compared to the intense transitions of the corresponding radical anions and have much higher oscillator strengths, which was confirmed experimentally for 2. An empirical kinetic model was proposed based on the analysis of the total charge passed through the cell during electrolysis and on the established mechanism of electrochemical reduction. This model perfectly described the UV-VIS-NIR optical density time dependences observed on 3D spectroelectrochemical surfaces for both compounds 1 and 2. This made it possible to explain the differences in the electrochromic behaviour of ambibolar electro-active polyimides with pendant groups based on 1, 2.

The synthesis and reactivity of the heavier group 13 phosphaketene complexes (2,6-Mes

The cocrystallization of 1,2,5-chalcogenadiazoles (chalcogen E = S, Se and Te) with cyclic polyethers 18-crown-6 (18-c-6) and dibenzo-18-crown-6 (db-18-c-6) yielded the molecular complexes characte...

Transiente, aus Bis(m-terphenyl)fluorpniktogenendurch Fluorid-Abstraktion gebildete Phosphenium- und Ar-senium-Ionen vollzogen einen intramolekularen elektrophilenAngriff, gefolgt von einer Methylgruppenwanderung und bil-deten isolierbare 9-Phospha- und 9-Arsena-Fluorenium-Ionen.

Herein, we report a semiconductive, proton-conductive, microporous hydrogen-bonded organic framework (HOF) derived from phenylphosphonic acid and 5,10,15,20‐tetrakis[p‐phenylphosphonic acid] porphyrin (GTUB5). The structure of GTUB5 was characterized using single crystal X-ray diffraction. A narrow band gap of 1.56 eV was extracted from a UV-Vis spectrum of pure GTUB5 crystals, in excellent agreement with the 1.65 eV band gap obtained from DFT calculations. The same band gap was also measured for GTUB5 in DMSO. The proton conductivity of GTUB5 was measured to be 3.00 × 10−6 S cm−1 at 75 °C and 75% relative humidity. The surface area was estimated to be 422 m2 g−1 from grand canonical Monte Carlo simulations. XRD showed that GTUB5 is thermally stable under relative humidities of up to 90% at 90 °C. These findings pave the way for a new family of organic, microporous, and semiconducting materials with high surface areas and high thermal stabilities., Research in hydrogen-bonded organic frameworks (HOFs) has gained interest in recent years due to their facile design and synthesis but no semiconducting HOF has been reported to date. Here the authors report a thermally stable and proton-conductive organic semiconductor based on a porphyrin HOF.

This review is divided into three different parts. In the introduction, the current applications of metal‐organic frameworks (MOFs) are shown. Furthermore, the overall stability, a comparison of phosphonate MOFs with carboxylate MOFs, the structural richness of phosphonate MOFs with the challenge in synthesis and different linker geometries is discussed. In the second part, several phosphonate MOFs with Y‐shaped planar, X‐shaped planar, and X‐shaped tetrahedral linker systems are described. The final part discusses different structures of inorganic building units (IBUs) with different metal atoms and a comparison of the formed MOF structures.

The reaction of 2-(tBuNCH)C6H4TeCl with silver salts of weakly coordinating anions, AgX {X = O3SCF3, SbF6, or Al[OC(CF3)3]4}, provided the aryltellurenyl salts [2-(tBuNCH)C6H4Te](O3SCF3) (1), [2-(t...

Reduction of 2,1,3-benzotelluradiazole (3) yielded a crystalline solid that features a trimeric dianion formally composed of two [3]˙− and one 3 bridged by unusually asymmetric Te⋯N chalcogen bonds. The solid is diamagnetic due to strong antiferromagnetic coupling, as revealed by CASSCF/CASPT2 and BS-DFT.

The new bidentate bisphosphino ligand (5-Ph2P-Ace-6-SiMe2)2 (1) binds rhodium(I) chloride and brings it into close proximity to a strong unpolar σ-Si–Si bond, in which it immediately inserts. In the spirocyclic Rh(III) product of the oxidative addition, (5-Ph2P-Ace-6-SiMe2)2RhCl (2), the two Si atoms are still close enough to engage in weak non-covalent interactions.

New electro-active polyimides (PI) with pendant groups based on 9H-thioxanthene-9-one (Th(O)S) and its S,S-dioxide derivative (Th(O)SO2) have been synthesized on the basis of 2-{bis(4-aminophenyl)aminomethyl}-9H-Th(O)S/Th(O)SO2 by the route including the synthesis of the corresponding polyamidoacids followed by their chemical imidization. The synthesized polyimides demonstrated thermal stability up to 400 °C without a noticeable weight loss. Thin-layer cyclic voltammetry showed the polyimides to be capable of reversible electron transfer at low negative potentials, their values depending on the nature of the pendant groups. The electrochromic behavior of the polyimides showed absorption bands at 363, 409, 683 nm for the PI with the Th(O)S pendant group and 355, 644 nm for the PI with the Th(O)SO2 in the potential sweep range 0 > E > −2.1 V. Optical absorption bands under electrochemical reduction conditions are associated with the formation of radical anion states of the pendant groups inside the PI layer as well as reversible electron transfer to the electron-acceptor moiety of the polymer chain. It was confirmed by comparison with 3D UV-VIS-NIR spectroelectrochemical studies of the corresponding 2-methyl-9H-thioxanthene-9-ones used as precursors of the pendant groups.

Herein, we report on the synthesis of a microporous, three-dimensional phosphonate metal-organic framework (MOF) with the composition Cu 3 (H 5 -MTPPA) 2 ·2 NMP (H 8 -MTPPA = methane tetra- p -phenylphosphonic acid and NMP = N-methyl-2-pyrrolidone). This MOF, termed TUB1, has a unique one-dimensional inorganic building unit composed of square planar and distorted trigonal bipyramidal copper atoms. It possesses a (calculated) BET surface area of 766.2 m 2 /g after removal of the solvents from the voids. The Tauc plot for TUB1 yields indirect and direct band gaps of 2.4 eV and 2.7 eV, respectively. DFT calculations reveal the existence of two spin-dependent gaps of 2.60 eV and 0.48 eV for the alpha and beta spins, respectively, with the lowest unoccupied crystal orbital for both gaps predominantly residing on the square planar copper atoms. The projected density of states suggests that the presence of the square planar copper atoms reduces the overall band gap of TUB1, as the beta-gap for the trigonal bipyramidal copper atoms is 3.72 eV.

Kinetic stabilization using bulky m-terphenyl substituents is the key to the isolation of the diarylantimony and diarylbismuth phosphaethynolates (2,6-Mes2C6H3)2EPCO and the related N-heterocyclic carbene complexes (2,6-Mes2C6H3)2EP(O)C(IMe4) (E=Sb, Bi; IMe4=1,3,4,5-tetramethylimidazol-2-ylidene), which have been fully characterized crystallographically and spectroscopically. The experimental characterization was augmented by a DFT based real space bond indicator analysis of the electron density, including AIM, NCI, and ELI-D methods., Zeitschrift für anorganische und allgemeine Chemie, 648 (19), ISSN:1521-3749, ISSN:0044-2313

The N[triple bond, length as m-dash]N triple bond can be cleaved in silico with a light atom molecule containing only the earth abundant elements C, H, Si, and P. Extensive density functional theory (DFT) computations on various classes of peri-substituted scaffolds containing Lewis acidic and basic sites in the framework of frustrated Lewis pairs (FLP) indicate that the presence of two silyl cations and two P atoms in a flexible but not too flexible arrangement is essential for energy efficient N2-activation. The non-bonding lone-pair electrons of the P atoms thereby serve as donors towards N2, whereas the lone-pairs of N2 donate into the silyl cations. Newly formed lone-pair basins in the N2-adducts balance surplus charge. Thereby, the N–N bond distance is increased by astonishing 0.3 Å, from 1.1 Å in N2 gas to 1.4 Å in the adduct, which makes this bond prone to subsequent addition of hydride ions and protonation, forming two secondary amine sites in the process and eventually breaking the N[triple bond, length as m-dash]N triple bond. Potential formation of dead-end states, in which the dications (“active states”) aversively form a Lewis acid (LA)–Lewis base (LB) bond, or in which the LA and LB sites are too far away from each other to be able to capture N2, are problematic but might be circumvented by proper choice of spacer molecules, such as acenaphthalene or biphenylene, and the ligands attached to the LA and LB atoms, such as phenyl or mesityl, and by purging the reaction solutions with gaseous N2 in the initial reaction steps. Charge redistributions via N2-activation and splitting were monitored by a variety of real-space bonding indicators (RSBIs) derived from the calculated electron and electron pair densities, which provided valuable insight into the bonding situation within the different reaction steps.

Noble gas atoms (Ng = He, Ne, Ar, and Kr) can be captured in silico with a light atom molecule containing only C, H, Si, O, and B atoms. Extensive density functional theory (DFT) calculations on series of peri-substituted scaffolds indicate that confined spaces (voids) capable to energy efficiently encapsulate and bind Ng atoms are accessible by design of a tripodal peri-substituted ligand, namely, [(5-Ph2B-xan-4-)3Si]H (xan = xanthene) comprising (after hydride abstraction) four Lewis acidic sites within the cationic structure [(5-Ph2B-xan-4-)3Si]+. The host (ligand system) thereby provides an adoptive environment for the guest (Ng atom) to accommodate for its particular size. Whereas considerable chemical interactions are detectable between the ligand system and the heavier Ng atoms Kr and Ar in the host guest complex [(5-Ph2B-xan-4-)3Si·Ng]+, the lighter Ng atoms Ne and He are rather tolerated by the ligand system instead of being chemically bound to it, nicely highlighting the gradual onset of (weak) chemical bonding along the series He to Kr. A variety of real-space bonding indicators (RSBIs) derived from the calculated electron and pair densities provides valuable insight to the situation of an “isolated atom in a molecule” in case of He, uncovering its size and shape, whereas minute charge rearrangements caused by polarization of the outer electron shell of the larger Ng atoms results in formation of polarized interactions for Ar and Kr with non-negligible covalent bond contributions for Kr. The present study shows that noble gas atoms can be trapped by small light-atom molecules without the forceful conditions necessary using cage structures such as fullerenes, boranes and related compounds or by using super-electrophilic sites like [B12(CN)11]− if the chelating effect of several Lewis acidic sites within one molecule is employed.

The bis(ferrocenyl)phosphenium ion, [Fc2P]+, reported by Cowley et al. (J. Am. Chem. Soc. 1981, 103, 714–715), was the only claimed donor‐free divalent phosphenium ion. Our examination of the molecular and electronic structure reveals that [Fc2P]+ possesses significant intramolecular Fe⋅⋅⋅P contacts, which are predominantly electrostatic and moderate the Lewis acidity. Nonetheless, [Fc2P]+ undergoes complex formation with the Lewis bases PPh3 and IPr to give the donor–acceptor complexes [Fc2P(PPh3)]+ and [Fc2P(IPr)]+ (IPr=1,3‐bis(2,6‐diisopropylphenyl)imidazole‐2‐ylidene)., Lineup of suspects: Interest in kinetically stabilized pnictogenium ions prompted the re‐investigation of the bis(ferrocenyl)phosphenium ion, the only claimed donor‐free divalent phosphenium ion. Iron was found guilty of charge compensation.

Organic light-emitting diodes (OLEDs) are revolutionizing display applications. In this aspect, luminescent complexes of precious metals such as iridium, platinum, or ruthenium still playing a significant role. Emissive compounds of earth-abundant copper with equivalent performance are desired for practical, large-scale applications such as solid-state lighting and displays. Copper(I)-based emitters are well-known to suffer from weak spin-orbit coupling and a high reorganization energy upon photoexcitation. Here we report a cationic organo-copper cluster [Cu4(PCP)3]+ (PCP = 2,6-(PPh2)2C6H3) that features suppressed nonradiative decays, giving rise to a robust narrow-band green luminophore with a photoluminescent (PL) efficiency up to 93%. PL decay kinetics corroborated by DFT calculations reveal a complex emission mechanism involving contributions of both thermally activated delayed fluorescence and phosphorescence. This robust compound was solution-processed into a thin film in prototype OLEDs with external quantum efficiency up to 11% and a narrow emission bandwidth (65 nm fwhm).

A stable ionic κ2Sn,P-coordinated Ru complex shows excellent catalytic activity in aerobic oxidations of benzylamine and benzyl alcohol. This complex is stabilized by a stannylene-phosphine peri-substituted naphthalene ligand, which can act as either a reducing agent for a Ru(III) complex or as a κ2Sn,P-chelating ligand for Ru(II) compounds.

The reaction of the polyfluorinated lithium triarylmethanolates Ar3COLi (Ar = C6F5, 3,5-(CF3)2C6H3) with SiCl4 provided the monosubstituted products Ar3COSiCl3 (1a, Ar = C6F5; 1b, Ar = 3,5-(CF3)2C6H3). The hydrolysis of 1a and 1b produced the silanetriols Ar3COSi(OH)3 (2a, Ar = C6F5; 2b, Ar = 3,5-(CF3)2C6H3) without the aid of an HCl scavenger. The reaction of two equivalents of (C6F5)3COH with (Cl3Si)2O afforded the disubstituted product [(C6F5)3COSiCl2]2O (3a), the hydrolysis of which gave the corresponding disiloxanetetraol [(C6F5)3COSi(OH)2]2O (4a). At high concentrations, 2b undergoes condensation to yield the related [(3,5-(CF3)2C6H3)3COSi(OH)2]2O (4b). In the solid-state, 2a, 4a and 4b are mainly associated by hydrogen bonds of the type SiO-H···O(H)Si whereas the competing SiO-H···O(C)Si type was not observed.

Herein, we report on the synthesis of a microporous, three-dimensional phosphonate metal-organic framework (MOF) of the composition Cu3(H5-MTPPA)2·2 NMP (H8-MTPPA = methane tetra-p-phenylphosphonic acid and NMP = N-methyl-2-pyrrolidone). This MOF, termed TUB1, has a unique one-dimensional inorganic building unit composed of square planar and distorted trigonal bipyramidal copper atoms. It possesses a (calculated) BET surface area of 766.2 m2/g after removal of the solvents from the voids. The Tauc plot for TUB1 yields indirect and direct band gaps of 2.4 eV and 2.7 eV, respectively. DFT calculations reveal the existence of two spin-dependent gaps of 2.60 eV and 0.48 eV for the alpha and beta spins, respectively, with the lowest unoccupied crystal orbital for both gaps predominantly residing on the square planar copper atoms. The projected density of states suggests that the presence of the square planar copper atoms reduces the overall band gap of TUB1, as the beta-gap for the trigonal bipyramidal copper atoms is 3.72 eV.

The condensation of 4,4’-dimethyldiphenylether with tellurium tetrachloride yielded 2,8-dimethyl-10,10-dichlorophenoxatellurine (3), which was characterized by X-ray diffraction. Unlike the parent phenoxatellurine (1) and the 10,10,-dichlorophenoxatellurine (2) showing butterfly conformations, 3 reveals a planar ring structure.