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Single crystals of mixed valent barium titanium(III/IV) chlorosilicate, Ba3Ti2Si4O14Cl0.91O0.09, were grown in a high temperature molten chloride flux involving an in situ reduction step. The fresnoite structure related Ba3Ti2Si4O14Cl0.91O0.09 crystallizes in the tetragonal space group P4/mbm with lattice parameters of a=8.6717(2) A, c=18.6492(5) A. The title compound exhibits a 3D structure consisting of 2D layers of fused Ti2O9 and Si4O12 groups and 2D layers of fused Ti2O9Cl2 and Si2O7 groups that are linked via barium atoms. The in situ reduction of Ti(IV) to Ti(III) is achieved via the addition of metallic Mg to the flux to function as the reducing agent. The temperature dependence of the magnetic susceptibility shows simple paramagnetism above 100 K. There is a discontinuity in the susceptibility data below 100 K, which might be due to a structural change that takes place resulting in charge ordering.

A series of monochloride-bridged, dinuclear metallacycles of the general formula [M2(μ-Cl)(μ-L)2](ClO4)3 have been prepared using the third-generation, ditopic bis(pyrazolyl)methane ligands L = m-bis[bis(1-pyrazolyl)methyl]benzene (Lm), M = Cu(II), Zn(II), and L = m-bis[bis(3,5-dimethyl-1-pyrazolyl)methyl]benzene (Lm*), M = Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II). These complexes were synthesized from the direct reactions of M(ClO4)2·6H2O, MCl2, and the ligand, Lm or Lm*, in the appropriate stoichiometric amounts. Three analogous complexes of the formula [M2(μ-Cl)(μ-L)2](BF4)3, L = Lm, M = Cu(II), and L = Lm*, M = Co(II), Cu(II), were prepared from the reaction of [M2(μ-F)(μ-L)2](BF4)3 and (CH3)3SiCl. The bromide-bridged complex [Cu2(μ-Br)(μ-Lm*)2](ClO4)3 was prepared by the first method. Three acyclic complexes, [Co2(μ-Lm)μ-Cl4], [Co2(μ-Lm*)Cl4], and [Co2(μ-Lm*)Br4], were also prepared. The structures of all [M2(μ-X)(μ-L)2]3+ (X = Cl–, Br–) complexes have two ditopic bis(pyrazolyl)methane ligands ...

The noncentrosymmetric tungstate oxide, Ce18W10O57) was synthesized for the first time as high-quality single crystals via the molten chloride flux method and structurally characterized by single-crystal X-ray diffraction. The compound is a structural analogue to the previously reported La18W10O57, which crystallizes in the hexagonal space group P (6) over bar 2c. The +3 oxidation state of cerium in Ce18W10O57 was achieved via the in situ reduction of Ce(IV) to Ce(III) using Zn metal. The structure consists of both isolated and face-shared WO6 octahedra and, surprisingly, isolated WO6 trigonal prisms. A careful analysis of the packing arrangement in the structure makes it possible to explain the unusual structural architecture of Ce18W10O57, which is described in detail. The temperature-dependent magnetic susceptibility of Ce18W10O57 indicates that the cerium(III) f(1) cations do not order magnetically and exhibit simple paramagnetic behavior. The SHG efficiency of Ln(18)W(10)O(57) (Ln = La, Ce) was measured as a function of particle size, and both compounds were found to be SHG active with efficiency approximately equal to that of alpha-SiO2.

The (POBOP)NiCl pincer complex (POBOP = 1,7-OP(i-Pr)2-m-carboranyl) was synthesized by the selective B H activation of the chelating carboranyl ligand and structurally and spectroscopically characterized. The reaction of (POBOP)NiCl and 1 equiv. of I2 at room temperature led to the selective iodination of the vicinal B H bond in the complex. The reaction of (POBOP)NiCl and 7 equiv. of I2 at room temperature led to further iodination of the ligand and dissociation of the metal from the complex.

Single crystals of two new uranyl silicates were grown from mixed alkali fluoride/alkali chloride fluxes. Polymorphism is observed in Cs2(UO2)Si2O6, where hydrothermal conditions lead to the α polymorph and flux growth favors the β polymorph. Rb2(UO2)Si2O6 crystallizes in a monoclinic distortion of the α-Cs2(UO2)Si2O6 structure type with space group I2/a and lattice parameters a = 14.9932(5) A, b = 14.8032(5) A, c = 16.2377(9) A, and β = 90.7220(10)°. β-Cs2(UO2)Si2O6 constitutes a new polymorph of Cs2(UO2)Si2O6 and crystallizes in the monoclinic space group C2 with lattice parameters a = 12.136(2) A, b = 10.0426(17) A, c = 7.7896(13) A, and β = 95.849(4)°. The two structures are compared, the driving force behind the observed polymorphism is discussed, and the luminescence properties are reported for each compound.

Columnar assembled pyridyl bis-urea macrocycles 1 provide a strong 1D supramolecular synthon to construct hierarchical assemblies. These 1D pillars contain ditopic symmetrical acceptors in the form of basic oxygen lone pairs. Herein, we probe this synthon with a series of activated halogen bond donors, the regio-isomers of diiodotetrafluorobenzenes, which vary the relative orientation of the halogen bond formers. Irrespective of the initial stoichiometry, each donor only formed one type of co-crystal with 1. In each case, similar strong pillars of assembled 1 were observed that organize the donors through the CO⋯I interaction, which were significantly shorter than the sum of the van der Waals radii of the atoms involved and among the shortest reported for neutral organic molecules. X-ray photoelectron spectroscopy characteristic core level shifts strongly indicated the formation of halogen bonding interactions. These studies suggest that this synthon can utilize both hydrogen and halogen bonding orthogonally to build complex structures.

Photophysics and dynamics of chromophores with a benzylidene imidazolinone core, responsible for emission of green fluorescent protein variants, were studied as a function of host topology by three approaches. Coordinative, non-coordinative, and “fastened” immobilization were utilized to study chromophore emission. Variable-temperature quadrupolar spin-echo 2H NMR spectra are reported.

Rapid and significant transformation is occurring within the private sector of the health care system with consolidation, integration and the formation of new organizational structures such as Accountable Care Organizations. However, the safety-net systems upon which many patients rely, have remained largely in silos. To focus a spotlight on this issue at a community level we have compared the safety net in Alameda County, California and Denver, Colorado, the former with a safety net largely in silos and the latter an integrated safety net. We have discussed the policy implications and have delineated some of the levers that could be utilized to facilitate greater safety-net integration.

High quality single crystals of the monoclinic phase K5U5O17(OH) were synthesized via a hydrothermal method utilizing the supercritical regime of water. The structure of K5U5O17(OH) is isotypic with the Na phase, Na5U5O17(OH), however crystallizes in a slightly different space group due to size effects. K5U5O17(OH) has the same sheet-anion structure as the Na analog, whose topology is analyzed here for the first time. K5U5O17(OH) shows fluorescence typical for uranyl species.

Single crystals of five transition metal uranium fluorides were obtained via the use of a mild hydrothermal route. Uranyl acetate was used as both the uranium source and the reducing agent for an in situ reduction of U(VI) to U(IV). The synthesized materials are present as both two- and three-dimensional structures and contain uranium in 9-fold coordination environments. Magnetic susceptibility measurements indicate that the reported materials remain paramagnetic down to 2 K, with no evidence for the existence of long-range magnetic ordering. Thermogravimetric analysis studies of the reported materials are also presented.

Ru6(μ6-C)(CO)17, 1, has been shown to react with C2H2 when activated by Me3NO to yield the complexes Ru6C(CO)15(μ–η2-C2H2NMe3), 2, and Ru6C(CO)14(μ3–η4-C4H4NMe3), 3, containing a bridging 2-trimeth...

Wild pigs are recognized as one of the greatest vertebrate modifiers of natural plant communities in existence and are frequently considered to be ecosystem engineers. Their diet is predominately comprised of plant materials despite being classified as a generalist and omnivore. Direct and indirect consequences of competition between wild pigs and native wildlife may manifest in several forms. Manifestations occur through interactions known as exploitative, interference, and apparent competition. Wild pig morphology, coupled with a highly plastic and opportunistic diet, allows access to a wide variety of animal prey. Generally, nearly all animals spending at least a portion of their lives on the ground are candidates for predation by wild pigs. Damage to forests is common where wild pigs occur in North America. Activity of wild pigs inhibits germination, and thus regeneration of numerous fruiting species, including conifer and deciduous taxa.

A series of lanthanide tungsten oxychlorides with compositions of La

The effect of donor (D)-acceptor (A) alignment on the materials electronic structure was probed for the first time using novel purely organic porous crystalline materials with covalently bound two- and three-dimensional acceptors. The first studies towards estimation of charge transfer rates as a function of acceptor stacking are in line with the experimentally observed drastic, eight-fold conductivity enhancement. The first evaluation of redox behavior of buckyball- or tetracyanoquinodimethane-integrated crystalline was conducted. In parallel with tailoring the D-A alignment responsible for "static" changes in materials properties, an external stimulus was applied for "dynamic" control of the electronic profiles. Overall, the presented D-A strategic design, with stimuli-controlled electronic behavior, redox activity, and modularity could be used as a blueprint for the development of electroactive and conductive multidimensional and multifunctional crystalline porous materials.

As part of the mm-Wave Interferometric Survey of Dark Object Masses (WISDOM), we present a measurement of the mass of the supermassive black hole (SMBH) in the nearby early-type galaxy NGC 0383 (radio source 3C 031). This measurement is based on Atacama Large Millimeter/sub-milimeter Array (ALMA) cycle 4 and 5 observations of the 12CO(2-1) emission line with a spatial resolution of 58x32pc2 (0."18x0."1). This resolution, combined with a channel width of 10 km/s, allows us to well resolve the radius of the black hole sphere of influence (measured as R_SOI = 316pc = 0."98), where we detect a clear Keplerian increase of the rotation velocities. NGC 0383 has a kinematically-relaxed, smooth nuclear molecular gas disc with weak ring/spiral features. We forward-model the ALMA data cube with the Kinematic Molecular Simulation (KinMS) tool and a Bayesian Markov Chain Monte Carlo method to measure a SMBH mass of (4.2+/-0.7)x10^9 Msun, a F160W-band stellar mass-to-light ratio that varies from 2.8+/-0.6 Msun/Lsun in the centre to 2.4+/-0.3 Msun/Lsun at the outer edge of the disc and a molecular gas velocity dispersion of 8.3+/-2.1 km/s (all 3-sigma uncertainties). We also detect unresolved continuum emission across the full bandwidth, consistent with synchrotron emission from an active galactic nucleus. This work demonstrates that low-J CO emission can resolve gas very close to the SMBH (~140,000 Schwarzschild radii) and hence that the molecular gas method is highly complimentary to megamaser observations as it can probe the same emitting material., 13 pages, 12 figures, accepted for publication in MNRAS 4th September 2019

A series of new Hf(IV)-containing fluorides with three different compositions, Cs

A series of N-arylimide molecular balances were developed to study and measure carbonyl–aromatic (CO−π) interactions. Carbonyl oxygens were observed to form repulsive interactions with unsubstituted arenes and attractive interactions with electron-deficient arenes with multiple electron-withdrawing groups. The repulsive and attractive CO−π aromatic interactions were well-correlated to electrostatic parameters, which allowed accurate predictions of the interaction energies based on the electrostatic potentials of the carbonyl and arene surfaces. Due to the pronounced electrostatic polarization of the C═O bond, the CO−π aromatic interaction was stronger than the previously studied oxygen−π and halogen−π aromatic interactions.

Ru5(μ5-C)(CO)15, 1, has been found to activate CH bonds in the vinyl group of polar vinyl olefins, methyl acrylate (MA), and vinyl acetate (VAc), through a cluster opening process to yield the complexes Ru5(μ5-C)(CO)14[η2-O═C(OMe)CH═CH](μ-H), 2, and Ru5(μ5-C)(CO)14[η2-(MeCO2)C═CH2](μ-H), 4, respectively. The site of CH activation is dependent on the olefin substituent. In 2, the site of CH activation is the β-carbon atom of the vinyl group, while in 4 the CH activation has occurred exclusively at the α-carbon atom of the vinyl group. Compound 2 can be further decarbonylated to yield the complex Ru5(μ5-C)(CO)13[μ-η3-O═C(OMe)CHCH](μ-H), 3, which contains a η3-bridging acryloyl ligand. Compound 2 reacts with ethylene in the presence of Me3NO to yield three new Ru5 products: Ru5(μ5-C)(CO)13[η4-1- anti,3- syn-{O═C(OMe)}C(H)C(H)C(H)Me](μ-H), 5, Ru5(μ5-C)(CO)12(C2H4)[μ-η3- O═C(OMe)C(H)C(H)](μ-H), 6, and Ru5(μ5-C)(CO)13[η4- anti-O═C(OMe)H2CHCHCH2](μ-H), 7. Compounds 5 and 7 are isomers containing substituted η3-allyl ligands formed by the coupling of the ethylene to the CH-activated β-carbon atom of the acryloyl ligand accompanied by some metal-mediated H-shifts. Compound 6 contains an uncoupled π-coordinated ethylene ligand. Compound 7 was isomerized to 5 thermally at 80 °C. Compound 4 reacts with ethylene in the presence of Me3NO to yield two new Ru5 products: Ru5(μ5-C)(CO)13[η4-1,1- anti- syn-[(O2CMe)C(Me)CHCH2](μ-H), 8, and Ru5(μ5-C)(CO)13[η4-1- anti-CH(Me)C(O2CMe)(CH2)](μ-H), 9. Compounds 8 and 9 both contain substituted η3-allyl ligands formed by the coupling of the ethylene to the CH-activated α-carbon atom of the vinyl acetyl ligand. Compound 8 was isomerized to 9 thermally at 80 °C. All new products were characterized structurally by single-crystal X-ray diffraction analyses.

The reaction of Re2(CO)8(μ-C6H5)(μ-H) (1) with furan in CH2Cl2 at 40 °C yielded two new isomeric dirhenium compounds, Re2(CO)8(μ-η2-2,3-C4H3O)(μ-H) (2) and Re2(CO)8(μ-η2-3,2-C4H3O)(μ-H) (3), which contain a bridging (σ + π)-coordinated furyl ligand formed by activation of the C–H bond at the 2 and 3 positions of furan, respectively. Compound 3 is the first example of a compound formed by C–H bond activation at the 3 position of a furan ring. Compound 3 was isomerized to 2 by heating to 80 °C for 7 days. The reaction of compound 2 with a second 1 equiv of 1 in CH2Cl2 at 40 °C yielded the doubly metalated furan-bis[Re2(CO)8(μ-H)] product [Re2(CO)8(μ-H)]2(μ-η2-2,3-μ-η2-5,4-C4H2O) (4) containing a 2,5-furdiyl ligand that is (σ + π)-coordinated to two Re2(CO)8(μ-H) groups by activation of the C–H bond at the 5 position of the furyl ligand in 2. Compound 2 can also be formed as the major isomer, together with a small quantity of 4 by heating furan with Re2(CO)8(μ-H)[μ-η2-C(H)═C(H)Bun] in toluene to reflux. An i...

Electronic structure modulation of metal-organic frameworks (MOFs) through the connection of linker "wires" as a function of an external stimulus is reported for the first time. The established correlation between MOF electronic properties and photoisomerization kinetics as well as changes in an absorption profile is unprecedented for extended well-defined structures containing coordinatively integrated photoresponsive linkers. The presented studies were carried out on both single crystal and bulk powder with preservation of framework integrity. An LED-containing electric circuit, in which the switching behavior was driven by the changes in MOF electronic profile, was built for visualization of experimental findings. The demonstrated concept could be used as a blueprint for development of stimuli-responsive materials with dynamically controlled electronic behavior.

We present high angular resolution (0.3" or 37 pc) Atacama Large Millimeter/sub-millimeter Array (ALMA) observations of the CO(2-1) line emission from a central disc in the early-type galaxy NGC 524. This disc is shown to be dynamically relaxed, exhibiting ordered rotation about a compact 1.3mm continuum source, which we identify as emission from an active supermassive black hole (SMBH). There is a hole at the centre of the disc slightly larger than the SMBH sphere of influence. An azimuthal distortion of the observed velocity field is found to be due to either a position angle warp or radial gas flow over the inner 2.5". By forward-modelling the observations, we obtain an estimate of the SMBH mass of $4.0^{+3.5}_{-2.0}\times10^8\,\mathrm{M_\odot}$, where the uncertainties are at the $3\sigma$ level. The uncertainties are dominated by the poorly constrained inclination and the stellar mass-to-light ratio of this galaxy, and our measurement is consistent with the established correlation between SMBH mass and stellar velocity dispersion. Our result is roughly half that of the previous stellar dynamical measurement, but is consistent within the uncertainties of both. We also present and apply a new tool for modelling complex molecular gas distributions., Comment: 17 pages, 9 figures, accepted for publication in MNRAS

We report the synthesis of a new flexible multimodal macrocyclic ligand, protected pyridyl bis-urea macrocycle 1, and two of its coordination polymers Cu2I2(1)2·(CH3CN)1.63 (2) and [Ag(1)](NO3).(H2O)2.49 (3). The ligand possesses conformational flexibility and adopts different conformations and binding modes depending on the metal ions. The crystal structure of 2 shows a 2D coordination network constructed from rhomboidal Cu2I2 dimer units and 1 as a bridging ligand binding through the pyridyl N atoms. 3 forms a sophisticated 3D structure with 1D chains formed by N-Ag-N links between pyridyl N atoms of two adjacent macrocyclic ligands and Ag(I) ions. These chains form 2D layers through longer Ag-O interactions and the chains are linked together into a 3D network by hydrogen bonding involving interstitial water molecules. These results indicate the potential of ligand 1 in the self-assembly of coordination polymers with diverse topology and functional applications.

The chloro-bridged carbene-substituted dicopper salt [{(IPr)Cu}2(µ-Cl)][PF6], 1, IPr = [N,N′-bis(2,6-diisopropylphenyl)imidazolin-2- ylidene], was synthesized by the reaction of (IPr)CuCl with Tl[PF6]. Reaction of 1 with the anion, [HOs3(CO)11]− of the salt [PPN][HOs3(CO)11], 2 yielded the Cu - Os heterometallic cluster complex, HOs3(CO)11[µ-Cu(IPr)], 3, the first example of Cu - Os bimetallic cluster complex containing a N-heterocyclic carbene ligand. Compounds 1 and 3 were characterized by IR, 1H NMR and structurally by single-crystal X-ray diffraction analysis. Compound 3 contains a triosmium carbonyl cluster with a bridging Cu(IPr) group on one edge of the cluster and a terminally-coordinated hydrido ligand on one of the Cu-bridged osmium atoms.

One new oxovanadium(IV) phosphate material, [H2en]4[V7P8O35(OH)6(H2O)]·3H2O was prepared utilizing a one step, mild hydrothermal route involving ethylenediamine as the reducing agent. The compound was structurally characterized by single crystal and powder X-ray diffraction methods and found to crystallize in the monoclinic space group C2/c. The temperature dependence of the magnetic susceptibility of was measured and found to be paramagnetic down to 2 K. The compound was further characterized by IR and UV–Vis spectroscopies.

Chirality transmission from point chirality to helical chirality was explored using triarylsilyl ethers. Circular dichroism (CD) spectroscopy was employed to show that the alcohol stereocenter of silylated, enantiopure secondary alcohols can transmit chirality to the aryl groups on the silicon resulting in a higher population of one helical conformation over another. Cotton effects characteristic of the aryl groups organized into one preferred conformation were observed for all of the compounds examined, which included both triphenyl- and trinaphthylsilyl groups. Alcohols with an R configuration typically induced a PMP helical twist, while an S configuration induced a MPM helical twist. Molecular modeling combined with solid-state structures also gave evidence signifying that point chirality adjacent to triphenylsilyl groups could bias the conformation of the phenyl groups. This work helps in our understanding of the origin of selectivity in our silylation-based kinetic resolutions and a role the phenyl groups play in that selectivity.

Single crystals of La0.516(3)Na0.484(3)MoO4, Ce0.512(2)Na0.488(2)MoO4, Pr0.502(2)Na0.498(2)MoO4, Nd0.501(2)Na0.499(2)MoO4, Sm0.509(2)Na0.491(2)MoO4, and Eu0.603(2)Na0.397(2)MoO4 were grown for the first time out of an alkali metal halide eutectic flux. All compounds crystallize in the tetragonal space group I41/a. UV/Vis measurements show the presence of an absorption edge for all compounds except Eu0.603(2)Na0.397(2)MoO4. The temperature dependence of the magnetic susceptibility was measured for all compounds and found to be paramagnetic across the entire 2–300 K temperature range measured.

Four new reduced lanthanide molybdenum oxides containing mixed valent Mo(V/VI)O4 tetrahedra were prepared in single crystal form by utilizing a high temperature molten salt flux synthesis involving an in situ reduction step. Calculations support the experimentally observed result that large alkali metal cations such as cesium are superior compared to the smaller alkali metal cations such as sodium in solvating O2– to facilitate oxide crystal growth in halide melts. All four compounds were structurally characterized by single crystal and powder X-ray diffraction methods and were found to crystallize in the cubic space group Pn3n. The temperature dependence of the magnetic susceptibility of these compounds was measured, and all were found to exhibit simple paramagnetism.

Crystals of Na5Pr4F[GeO4]4 and Na5Nd4F[GeO4]4 were synthesized using a eutectic sodium fluoride, sodium chloride flux. Both compounds crystallize in the tetragonal space group I-4 with lattice parameters of a=12.1173(4) A and c=5.6795(2) A (Pr) and of a=12.0642(17) A and c=5.6674(11) A (Nd). The structure of the reported compounds is three-dimensional with face and corner sharing lanthanide polyhedra which edge and corner share with isolated germanium tetrahedra. These novel compositions represent the first example of quaternary germanium containing oxyfluorides.

A series of six anti-perovskite fluorides of the type [Cu(H2O)4]3(M1-xM'xF6)2 (where M and M' = V, Cr, Mn, Fe as well as M = Fe and M' = V and Cr) was synthesized as high-quality single crystals via a mild hydrothermal route. These materials belong to a class of perovskite-based structures in which the anions and cations of the regular ABX3 perovskite structure have exchanged positions. Two complex anions, MF6(3-) and M'F6(3-), occupy the normal A and B cation positions, while three complex cations, [Cu(H2O)4](2+), occupy the normally anionic X positions. As in the ABX3 compositions, the A and B positions can be occupied by different complex anions, allowing for the preparation of a wide range of compositions. Magnetic property measurements were performed on all six phases, and complex magnetic behavior was observed at low temperatures in the Mn, Fe, and bimetallic Fe/V and Fe/Cr phases.

Engineering of novel systems capable of efficient energy capture and transfer in a predesigned pathway could potentially boost applications varying from organic photovoltaics to catalytic platforms and have implications for energy sustainability and green chemistry. While light-harvesting properties of different materials have been studied for decades, recently, there has been great progress in the understanding and modeling of short- and long-range energy transfer processes through utilization of metal-organic frameworks (MOFs). In this Forum Article, the recent advances in efficient multiple-chromophore coupling in well-defined metal-organic materials through mimicking a protein system possessing near 100% energy transfer are discussed. Utilization of a MOF as an efficient replica of a protein β-barrel to maintain chromophore emission was also demonstrated. Furthermore, we established a novel dependence of a photophysical response on an electronic configuration for chromophores with the benzylidene imidazolinone core. For that, we prepared 16 chromophores, in which the benzylidene imidazolinone core was modified with electron-donating and electron-withdrawing substituents. To establish the structure-dependent photophysical properties of the prepared chromophores, 11 novel molecular structures were determined by single-crystal X-ray diffraction. These findings allow one to predict the chromophore emission profile inside a rigid framework as a function of the substituent, a key parameter for achieving the spectral overlap necessary to study and increase resonance energy transfer efficiency in MOF-based materials.

Salt-inclusion compounds (SICs) are known for their structural diversity and their potential applications, including luminescence and radioactive waste storage forms. Currently, the majority of salt-inclusion phases are grown serendipitously and the targeted growth of SICs has met with only moderate success. We report an enhanced flux growth method for the targeted growth of SICs. Specifically, the use of (1) metal halide reagents and (2) reactions with small surface area to volume ratios are found to favor the growth of salt-inclusion compounds over pure oxides and thus enable a more targeted synthetic route for their preparation. The Cs-X-U-Si-O (X = F, Cl) pentanary phase space is used as a model system to demonstrate the generality of this enhanced flux method approach. Single crystals of four new salt-inclusion uranyl silicates, [Cs3F][(UO2)(Si4O10)], [Cs2Cs5F][(UO2)2(Si6O17)], [Cs9Cs6Cl][(UO2)7(Si6O17)2(Si4O12)], and [Cs2Cs5F][(UO2)3(Si2O7)2], were grown using this enhanced flux growth method. A detailed discussion of the factors that favor salt-inclusion phases during synthesis and why specifically uranyl silicates make excellent frameworks for salt-inclusion phases is given.

The stabilizing and destabilizing effects of alkyl groups on an aromatic stacking interaction were experimentally measured in solution. The size (Me, Et, iPr, and tBu) and position (meta and para) of the alkyl groups were varied in a molecular balance model system designed to measure the strength of an intramolecular aromatic interaction. Opposite stability trends were observed for alkyl substituents at different positions on the aromatic rings. At the closer meta-position, smaller groups were stabilizing and larger groups were destabilizing. Conversely, at the farther para-position, the larger alkyl groups were systematically more stabilizing with the bulky tBu group forming the strongest stabilizing interaction. X-ray crystal structures showed that the stabilizing interactions of the small meta-alkyl and large para-alkyl groups were due to their similar distances and van der Waals contact areas with the edge of opposing aromatic ring.

Two new uranium(IV) fluorides, Na 3.13 Mg 1.43 U 6 F 30 ( 1 ) and Na 2.50 Mn 1.75 U 6 F 30 ( 2 ), were synthesized through an in situ mild hydrothermal route, and were structurally characterized by single crystal X-ray diffraction. The compounds exhibit complex crystal structures composed of corner- or edge-shared UF 9 and M F 6 ( M =Mg, Mn) polyhedra, forming hexagonal channels in the three-dimensional framework, in which ordered or disordered divalent metal and sodium atoms reside. The large hexagonal voids contain the nearly regular M(II)F 6 octahedra and sodium ions, whereas the small hexagonal cavities include M(II) and sodium ions on a mixed-occupied site. Magnetic susceptibility measurements yielded effective magnetic moments of 8.36 and 11.6 µ B for 1 and 2 , respectively, confirming the presence and oxidation states of U(IV) and Mn(II). The large negative Weiss constants indicate the spin gap between a triplet and a singlet state in the U(IV). Magnetization data as a function of applied fields revealed that 2 exhibits paramagnetic behavior due to the nonmagnetic singlet ground state of U(IV) at low temperature. UV–vis diffuse reflectance and X-ray photoelectron spectroscopy data were also analyzed.

Here, we compare structures determined by X-ray diffraction and subsequent Hirshfeld surface analysis to identify and understand the non-covalent interactions within the lattices of chromone, 6-methylchromone, 6-methoxychromone, 6-fluorochromone, and 6-chlorochromone with reported 6-bromochromone. In chromone, H-bonds and CH–л interactions predominate. H-bonds and aryl-stacking interactions are distinct in 6-methylchromone and 6-methoxychromone. The 6-fluorochromone, showed two types of H-bonds with O···H bonds having a greater contribution than F···H. In contrast, 6-chlorochromone and 6-bromochromone, the halogen contributes the larger percentage of stabilizing H-bonding with Cl···H and Br···H predominating over the O···H bonds. Compound 1 crystallizes in the monoclinic space group P21 /n with a = 8.1546(8) A, b = 7.8364(7) A, c = 11.1424(11) A, β = 108.506(2)° and Z = 4. Compound 2 crystallizes in the triclinic space group P-1 with a = 7.0461(3) A, b = 10.2108(5) A, c = 10.7083(5) A, α = 89.884(2)°, β = 77.679(2)°, γ = 87.367(2)° and Z = 4. Compound 3 crystallizes in the monoclinic space group P21/n with a = 8.1923(4) A, b = 7.0431(3) A, c = 15.3943(8) A, β = 92.819(2)° and Z = 4. Compound 4 crystallizes in the triclinic space group P1 with a = 3.7059(2) A, b = 6.1265(4) A, c = 7.6161(5) A, α = 84.085(3)°, β = 87.070(3)°, γ = 83.390(3)° and Z = 1. Compound 5 crystallizes in the monoclinic space group P2 1 with a = 3.8220(2) A, b = 5.6985(2) A, c = 16.9107(7) A, β = 95.8256(18)° and Z = 2. The effect of substituents at the 6-position on chromone on their crystal structures using Hirshfeld surface and fingerprint analysis.

Four new members of the A3LnSi2O7 family, K3SmSi2O7, Na3HoSi2O7, and two polymorphs of Na3YbSi2O7, are reported. K3SmSi2O7 crystallizes in the hexagonal space group P63/mcm, Na3HoSi2O7 and Na3YbSi2O7 crystallize in the hexagonal space group P63/m, and Na3YbSi2O7 crystallizes in the trigonal space group P31c. The Na3YbSi2O7 composition that crystallizes in P31c is a new structure type. The magnetic properties for the Ho and Yb analogs are reported.

We report the synthesis of the chelating phosphinite-arm carboranyl POBOP-H (POBOP = 1,7-OP(i-Pr)2-m-carboranyl) ligand precursor, preparation of its rhodium complexes, and their reactivity in oxidative addition/reductive elimination reactions. The oxidative addition of iodobenzene to the low-valent (POBOP)Rh(PPh3) resulted in the selective formation of the 16-electron complex (POBOP)Rh(Ph)(I), featuring a highly strained exohedral rhodium–boron bond. The complex (POBOP)Rh(Ph)(I) is the first example of a B-carboranyl aryl metal complex, which is a proposed intermediate in metal-promoted B–C coupling reactions. The complex (POBOP)Rh(Ph)(I) was selectively and directly converted, in the presence of acetonitrile, to (POB(BPh)OP)Rh(H)(I)(CH3CN) (POB(BPh)OP = 1,7-OP(i-Pr)2-2-Ph-m-carboranyl) through unprecedented cascade reductive elimination of the phenyl-B-carboranyl and the oxidative addition of a vicinal B–H bond of the boron cluster to the metal center, exhibiting both metal- and cluster-centered reactivity.

The activation of O-H bonds of water at room temperature driven by the cage-opening rearrangement of a biscarborane-based cluster is reported. The reaction of the 12-vertex-closo-12-vertex-nido biscarborane cluster with water led to the quantitative and selective two-vertex decapitation of a carborane cluster and formation of the pendent boronic acid hydride B(H)(OH) group. Remarkably, this transformation can be quantitatively reversed with the release of water and re-formation of the starting biscarborane cage. The flexibility of cage decapitation/expansion and its influence on the reactivity of an exohedral substituent represent a new approach to cluster-induced organic transformations.

Crystals of Na 2 ScSiO 4 (OH) and Na 2 YbSiO 4 (OH) were synthesized at low temperatures using a sodium hydroxide based hydroflux, while crystals of NaLaSiO 4 and NaYbSiO 4 were grown at high temperatures using a sodium fluoride/sodium chloride eutectic flux. Both structure types were crystallized under reaction conditions that, when used for medium sized rare earths (RE = Pr, Nd, Sm – Tm) yield the Na 5 RE 4 X[SiO 4 ] 4 structure type, where X is OH in the hydroflux conditions and F in the eutectic flux conditions. Herein, we report the synthesis, structure, size effect, and magnetic properties of these compositions and introduce the new structure type of Na 2 RESiO 4 (OH), which crystallizes in the orthorhombic space group Pca 2 1 , of NaLaSiO 4 , which crystallizes in the orthorhombic space group Pna 2 1 , and of NaYbSiO 4 , which crystallizes in the orthorhombic space group Pnma , where both NaRESiO 4 compounds have one silicon structural analog.

In this paper, a rigid scaffold imposes the photophysics of chromophores with a benzylidene imidazolidinone core by mimicking the β-barrel structure of the green fluorescent protein (GFP) and its analogs. The designed artificial frameworks maintain fluorescence responses and, therefore, conformational rigidity of typically non-emissive GFP-related chromophores. To replicate a small weight percent of the chromophore inside the natural GFP, two synthetic approaches were utilized: coordinative immobilization and non-coordinative inclusion. Despite low chromophore loading in the rigid matrix, both approaches resulted in formation of photoluminescent hybrid materials. Furthermore, the rigid scaffold dictates chromophore fluorescence by replicating its behavior in solution or the solid state. The presented results open an avenue for utilization of rigid scaffolds in the engineering of materials with tunable photoluminescence profiles for a variety of practical applications.

Porous organic crystalline materials were obtained by the self-assembly of pyridyl-phenylethynylene bis-urea macrocycles (1). In contrast to the typical columnar assembly of other bis-urea macrocycles, 1 assembled into interdigitated layers to afford a host with small 1D channels with a pore diameter of ∼4.5 A. Herein, we discuss the origin between the expected and observed assembly and demonstrate the utility of these activated organic crystals to absorb a guest and maintain crystallinity during the reaction of the encapsulated guest and subsequent product isolation. Isoprene was chosen as a model monomer due to the small channel diameter of 1. The activated crystals were able to absorb isoprene and facilitate a photoinitiated and stereoselective oligomerization to produce trans-1,4-polyisoprene with low dispersity. The products were readily extracted from the crystals and analysis of the microstructure of the oligomer showed 97% trans-1,4 content and a dispersity (Đ) of 1.39. Despite the altered assembly pattern of this bis-urea macrocycle, powder X-ray diffraction studies demonstrated that the crystalline host was remarkably robust and stable throughout the activation, isoprene absorption, photoinduced polymerization, and product recovery processes. Our future investigations are focused on assessing the stability of the isoprene radicals within the host and evaluating the loading and reaction of other monomers.

Two polymorphs of K3YSi2O7, crystallizing in the space groups P63/mmc (1) and P63/mcm (2) can be synthesized by high temperature flux crystal growth. The flux growth conditions can be fine-tuned to yield a phase pure sample of polymorph (2), however, not of polymorph (1), which always co-crystallizes with polymorph (2). Polymorph (2) was found to exhibit intrinsic bluish-white light emission. Further studies determined that doping europium and dysprosium onto the yttrium site of this polymorph could readily tune the luminescence, with the purest white light emission found for the K3YSi2O7: 10% Dy, 0.1% Eu composition (K3Y0.899Dy0.1Eu0.001Si2O7) (2-Dy,Eu).

This manuscript reports on the modulation of the photoreactivity of a series of chromones, also known as benzo-γ-pyrones, by absorption into a porous self-assembled host formed from phenylethynylene bis-urea macrocycles. Chromone and four derivatives namely 6-fluorochromone, 6-bromochromone, 7-hydroxy-4-chromone, and 3-cyanochromone are unreactive in the solid-state. Each of these derivatives was loaded into the nanochannels of self-assembled phenylethynylene bis-urea macrocycles to form solid host·guest complexes, which were subsequently UV-irradiated at room temperature under argon atmosphere. We observed that chromone and 6-fluorochromone underwent selective [2 + 2] photodimerization reactions to produce anti-HT dimers in high selectivity and conversion. The 6-bromochromone also reacted in high selectivity and conversion to afford an aryl coupling adduct. In each case, the products were extracted, and the crystalline host recovered. In comparison, 7-hydroxy-4-chromone, and 3-cyanochromone were unreactive within the complex. Simple GCMC simulation studies suggest that chromone, 6-fluorochromone, and 6-bromochromone were loaded in orientations that facilitate photoreaction, and correctly predicted that the anti-HT dimer would be favored in the chromone case. In contrast, syn-HH dimers were predicted by GCMC simulations for the halogen containing derivatives but were not observed. The simulations with 7-hydroxy-4-chromone were in agreement with the observed reactivity. We compare these computational and experimental findings and suggest future methods for optimizing simulation parameters. Our goal is to expand the scope and accuracy of the simulations to be able to predict the reactivity of guests encapsulated within columnar nanotubes.

Single crystals of Rb0.74Ga6.62Ti0·38O11 (RGTO) were grown from a mixed RbCl–RbF flux at 850 °C. The compound crystallizes in the RbGa7O11 structure type, which is reminiscent of the hollandite and β-Ga2O3 structure types. RGTO crystallizes in the monoclinic space group P2/m with lattice parameters a = 8.3355 (8) A, b = 3.0286 (3) A, c = 9.5028 (9) A, and β = 114.620 (3)°. The crystal structure of RGTO is comprised of GaO6 and mixed (Ga/Ti)O6 octahedra and GaO4 tetrahedra connected in a complex three-dimensional, anionic framework exhibiting eight-sided channels that are occupied by disordered Rb cations required for charge balance. First-principles calculations in the form of density functional theory were performed, which indicated the complex to be a charge transfer semiconductor.

A family of new compounds with a general formula MIIMIIIF5(H2O)7 (MII = Co2+ and Ni2+, MIII = Mn3+, Ga3+, and In3+), along with a related compound [Ni(H2O)6][InF4(H2O)2]2, was obtained via hydrothermal crystal growth and characterized using single crystal X-ray diffraction. All compounds adopt related structural motifs and differ in slight symmetry distortions rather than overall change in packing. No direct relationships between the cation size and symmetry of the crystals were found, moreover, [Co(H2O)6]2[MnF4(H2O)2][MnF6] that exhibits Jahn-Teller distortions of the Mn octahedra adopts the same structure as [Ni(H2O)6]2[InF4(H2O)2][InF6], which is lacking such distortions. Magnetic and spectroscopic properties of the former compound are also reported.

Correction for ‘Multiple cluster CH activations and transformations of furan by triosmium carbonyl complexes’ by Richard D. Adams et al., Chem. Commun., 2018, 54, 3464–3467.

A comprehensive experimental survey consisting of 36 molecular balances was conducted to compare 18 pairs of S-π versus O-π interactions over a wide range of structural, geometric, and solvent parameters. A strong linear correlation was observed between the folding energies of the sulfur and oxygen balances across the entire library of balance pairs. The more stable interaction systematically switched from the O-π to S-π interaction. Computational studies of bimolecular PhSCH3-arene and PhOCH3-arene complexes were able to replicate the experimental trends in the molecular balances. The change in preference for the O-π to S-π interaction was due to the interplay of stabilizing (dispersion and solvophobic) and destabilizing (exchange-repulsion) terms arising from the differences in size and polarizability of the oxygen and sulfur atoms.

Single crystals of 13 new uranyl germanate salt-inclusion materials were grown from alkali halide fluxes: [Cs2Cs5F][(UO2)3(Ge2O7)2] (1), [Cs6Ag2Cl2][(UO2)3(Ge2O7)2] (2), [Cs6Ag0.3Na1.7Cl2][(UO2)3(Ge2O7)2] (3), [Cs6Ag0.4Na1.6Cl2][(UO2)3(Ge2O7)2] (4), [Cs6K2Cl2][(UO2)3(Ge2O7)2] (5), [Cs6K1.9Ag0.1Cl2][(UO2)3(Ge2O7)2] (6), [KK6Cl][(UO2)3(Ge2O7)2] (7), [KK6Br0.6F0.4][(UO2)3(Ge2O7)2] (8), [Na0.9Rb6.1F][(UO2)3(Ge2O7)2] (9), [K0.6Na0.4K5CsCl0.5F0.5][(UO2)3(Ge2O7)2] (10), [K0.8Na0.2K4.8Cs1.2Cl0.5F0.5][(UO2)3(Ge2O7)2] (11), [KK1.8Cs4.2F][(UO2)3(Ge2O7)2] (12), and [Cs6Cs0.71Cl0.71][(UO2)3O3(Ge2O7)] (13). Structures 1–12 contain the same [(UO2)3(Ge2O7)2]6– framework whose pores are filled with varied salt species selected by the choice of the specific alkali halide flux used for crystal growth. The size and identity of the salt species also influence whether the [(UO2)3(Ge2O7)2]6– framework adopts a monoclinic or orthorhombic symmetry. The 13th composition, [Cs6Cs0.71Cl0.71][(UO2)3O3(Ge2O7)] (13), crystallizes in a n...