Synthesis and Structure of Sn14Cl6(CH2SiMe3)12: Toward Nanoclusters of 4-Coordinate α-Sn.

Orange crystals of a Sn14 cluster have been isolated in up to 22% yield from a reaction between Me3SiCH2SnCl3, SnCl4, and LiAlH4. The structure determined by single crystal X-ray diffraction shows three unique Sn atoms in a 6:6:2 ratio, with all Sn atoms 4-coordinate, similar to the tetrahedral bonding in elemental gray Sn. The solid state 117Sn MAS NMR spectrum shows the three types of distinct Sn atoms in the expected 3:3:1 intensity ratio with respective chemical shifts of 87.9, -66.6, and -607.1 ppm relative to Me4Sn. The chemical shift of the two Sn atoms without ligands (bonded only to Sn), at -607.1 ppm, is the most upfield, and is the closest to the chemical shift, reported here, of bulk gray tin (-910 ppm). First-principles density functional theory calculations of the chemical shielding tensors corroborate this assignment. While the core coordination is distorted from the ideal tetrahedral arrangement in the diamond structure of gray tin, this Sn14 cluster, as the largest reported cluster with all 4-coordinate Sn, represents a major incremental step toward being able to prepare atomically precise nanoparticles of gray tin.

Tetracyanomethane under Pressure: Extended CN Polymers from Precursors with Built-in sp3 Centers.

Tetracyanomethane, C(CN)4, is a tetrahedral molecule containing a central sp3 carbon that is coordinated by reactive nitrile groups that could potentially transform to an extended CN network with a significant fraction of sp3 carbon. High-purity C(CN)4 was synthesized, and its physiochemical behavior was studied using in situ synchrotron angle-dispersive powder X-ray diffraction (PXRD) and Raman and infrared (IR) spectroscopies in a diamond anvil cell (DAC) up to 21 GPa. The pressure dependence of the fundamental vibrational modes associated with the molecular solid was determined, and some low-frequency Raman modes are reported for the first time. Crystalline molecular C(CN)4 starts to polymerize above ∼7 GPa and transforms into an interconnected disordered network, which is recoverable to ambient conditions. The results demonstrate feasibility for the pressure-induced polymerization of molecules with premeditated functionality.

High-pressure phase transition of alkali metal-transition metal deuteride Li2PdD2.

A combined theoretical and experimental study of lithium palladium deuteride (Li2PdD2) subjected to pressures up to 50 GPa reveals one structural phase transition near 10 GPa, detected by synchrotron powder x-ray diffraction, and metadynamics simulations. The ambient-pressure tetragonal phase of Li2PdD2 transforms into a monoclinic C2/m phase that is distinct from all known structures of alkali metal-transition metal hydrides/deuterides. The structure of the high-pressure phase was characterized using ab initio computational techniques and from refinement of the powder x-ray diffraction data. In the high-pressure phase, the PdD2 complexes lose molecular integrity and are fused to extended [PdD2]∞ chains. The discovered phase transition and new structure are relevant to the possible hydrogen storage application of Li2PdD2 and alkali metal-transition metal hydrides in general.

Pressure-Induced Polymerization of LiN(CN)2.

The high-pressure behavior of lithium dicyanamide (LiN(CN)2) was studied with in situ Raman and infrared (IR) spectroscopies, and synchrotron angle-dispersive powder X-ray diffraction (PXRD) in a diamond anvil cell (DAC) to 22 GPa. The fundamental vibrational modes associated with molecular units were assigned using a combination of experimental data and density functional perturbation theory. Some low-frequency modes were observed for the first time. On the basis of spectroscopic and diffraction data, we suggest a polymorphic phase transformation at ∼8 GPa, wherein dicyanamide ions remain as discrete molecular species. Above ca. 18 GPa, dicyanamide units polymerize, forming a largely disordered network, and the extent of polymerization may be increased by annealing at elevated temperature. The polymerized product consists of tricyanomelaminate-like groups containing sp2-hybidized carbon-nitrogen bonds and exhibits a visible absorption edge near 540 nm. The product is recoverable to ambient conditions but is not stable in air/moisture.

Di-aqua-bis-(2-ethyl-5-methyl-imidazole-4-sulfonato-κ(2) N (3),O)nickel(II) dihydrate.

In the title complex, [Ni(C6H9N2O3S)2(H2O)2]·2H2O, the Ni(II) atom lies on an inversion center and is chelated by N and O atoms of two symmetry-equivalent imidazole-sulfonate ligands in the basal plane, and two water O atoms in axial positions in an overall octa-hedral configuration. The crystal structure displays O-H⋯O and N-H⋯O hydrogen bonds, which connect the components into an extended three-dimensional network.

Poly[tetrakis(µ-1,1,1,3,3,3-hexafluoropropan-2-olato)iron(II)dipotassium].

The title compound, [K2Fe{OCH(CF3)2}4] n , was formed from the reaction of potassium hexa-fluoro-isopropoxide with iron(II) chloride in toluene. The Fe(II) atom has a highly distorted tetra-hedral coordination environment. All four of the non-equivalent hexa-fluoro-isoprop-oxy O atoms link the Fe(II) atoms to one of the K(+) atoms in an alternating chain of Fe-O-K-O fused four-membered rings, with K-Fe distances of 3.715 (2) and 3.717 (2) Å. This K(+) atom is also bridged to eight of the F atoms. The other K(+) atom is bonded to only two of the O atoms, but has seven short K⋯F contacts, one of which links the chains into a three-dimensional arrangement. Weak hydrogen bonding between the lone H atoms on the hexa-fluoro-isoprop-oxy groups and F atoms is also present. The crystal studied was refined as an inversion twin.

Bis(η(5)-penta-methyl-cyclo-penta-dien-yl)aluminium tetra-bromido-aluminate.

The title compound, [Al(C10H15)2][AlBr4], was formed during the reduction of a mixture of Cp*AlBr2 and AlBr3. The Al(III) atoms of the two crystallographically independent cations each lie on an inversion center, and the [AlBr4](-) anions are on general positions. At 123 K, the structure exhibits disorder in two of the Br atoms of the [AlBr4](-) ion, with a ratio occupancy of 0.733 (6): 0.267 (3). In the crystal, there is possible weak hydrogen bonding between some methyl groups and Br atoms. The interactions link the moieties in a three-dimensional array.

Cefiderocol: early clinical experience for multi-drug resistant gram-negative infections.

Multi-drug resistant gram-negative bacteria present a significant global health threat. Cefiderocol (CFDC), a siderophore cephalosporin, has shown potential in combating this threat, but with the currently available data, its role in therapy remains poorly defined. This multi-center, retrospective cohort study evaluated the real-world application of CFDC across six U.S. medical centers from January 2018 to May 2023. Patients aged ≥18 years and who had received ≥72 hours of CFDC were included. The primary outcome was a composite of clinical success: survival at 30 days, absence of symptomatic microbiologic recurrence at 30 days following CFDC treatment initiation, and resolution of signs and symptoms. Secondary outcomes included time to CFDC therapy and on-treatment non-susceptibility to CFDC. A total of 112 patients were included, with median (interquartile range [IQR]) APACHE II scores of 15 (19-18). Clinical success was observed in 68.8% of patients, with a mortality rate of 16.1% and comparable success rates across patients infected with carbapenem-resistant gram-negative infections. The most common isolated organisms were Pseudomonas aeruginosa (61/112, 54.5%, of which 55/61 were carbapenem-resistant) and carbapenem-resistant Acinetobacter baumannii (32/112, 28.6%). Median (IQR) time to CFDC therapy was 77 (14-141) hours. Two patients experienced a non-anaphylactic rash as an adverse drug reaction. On-treatment non-susceptibility to CFDC was found in six patients, notably due to P. aeruginosa and A. baumannii.IMPORTANCECFDC was safe and clinically effective as a monotherapy or in combination in treating a variety of carbapenem-resistant gram-negative infections. Further prospective studies are warranted to confirm these findings.

Thermodynamic and kinetic stabilities of CO2 oligomers.

Density-functional and coupled cluster calculations suggest that the stability, against unimolecular dissociation, of the cyclic D(3h) trimer of CO2, 1,3,5-trioxetanetrione, is greater than all but one other chemically bound oligomer of CO2. It requires far less energy to produce, on a per CO2 basis, than the low-symmetry cyclic 1,2 dioxetanedione dimer, but its kinetic stability against unimolecular dissociation is much lower. The extreme stability of the dimer, which makes it an excellent intermediate in chemiluminescence, is caused by an extreme range of geometric change to its transition state leading to a trapezoidal potential energy surface. The thermodynamically more stable trimer affords a low pressure pathway from molecular carbon dioxide to the extended covalent structure at high pressure.

catena-Poly[[(tetra-hydro-furan-κO)potas-sium]-di-µ-dimethyl-amido-κ(4) N:N-aluminium-di-µ-dimethyl-amido-κ(4) N:N-potassium-di-µ-dimethyl-amido-κ(4) N:N-aluminium-di-µ-dimethyl-amido-κ(4) N:N].

The title compound, [Al2K2(C2H6N)8(C4H8O)] n , formed during the sonochemical reaction between Al(NMe2)3 and sodium-potassium alloy in the presence of tetra-hydro-furan (THF). Its asymmetric unit has two inequivalent K(+) sites. One site is coordinated by a THF ligand, and crystallizes as a one-dimensional polymer with a backbone of catenated AlN2K rings. A twofold rotation axis bis-ects one K(+) site and the THF ligand; the second K(+) site is situated on an inversion centre, resulting in a planar four-coordination by N atoms. The latter symmetry operation generates the second half of the THF mol-ecule and fills out the coordination sphere of the potassium sites. The chains extend along the c-axis direction and zigzag at the THF-coordinated K(+) sites by an angle of 106.02 (5)°.

3,3'-(1-Oxopropane-1,3-di-yl)bis-(1,3-thia-zolidine-2-thione) chloro-benzene hemisolvate.

The title compound, C9H12N2OS4·0.5C6H5Cl, which contains two 1,3-thia-zolidine-2-thione rings, is a by-product of the synthesis of 3-acryloyl-1,3-thia-zolidine-2-thione. The dihedral angle between these rings is 79.95 (9)°, with both rings displaying a twisted conformation. The twist angle of the amide group is 5.6 (1)°. In the crystal, the molecules are linked into [001] chains by C-H⋯O interactions. The chloro-benzene solvent mol-ecule was found to show unresolvable disorder about a centre of inversion and its contribution to the scattering was removed with the SQUEEZE option in PLATON [Spek (2009 ▶). Acta Cryst. D65, 148-155].

Triclinic polymorph of bis-(triphenyl-sil-yl) oxide toluene disolvate.

A new polymorph of the title compound, C(36)H(30)OSi(2)·2C(7)H(8), is reported, which is triclinic (P-1) instead of possessing the previously reported rhombohedral symmetry [Hönle et al. (1990). Acta Cryst. C46, 1982-1984]. Each of the -SiPh(3) units are related by the inversion center. The Si-O-Si moiety is linear with the O atom sitting on an inversion center, and the O-Si-(toluene ring centroid) angle is 3.69 (15)°. Each toluene mol-ecule is 5.622 (2) Šfrom the Si atom and has its closest contacts with the phenyl rings outside of the van der Waals radii.

2-Ethyl-4-methyl-1H-imidazol-3-ium bromide.

In the title mol-ecular salt, C6H11N2 +·Br-, the components are linked by N-H⋯Br⋯H-N hydrogen bonds into C(8)chains of alternating cations and anions propagating in the b-axis direction; these chains are cross-linked in the c-axis direction by weak C-H⋯Br hydrogen bonds.

Surface- and Structural-Dependent Reactivity of Titanium Oxide Nanostructures with 2-Chloroethyl Ethyl Sulfide under Ambient Conditions.

Robust materials capable of heterogeneous reactivity are valuable for addressing toxic chemical clean up. Synthetic manipulations for generating titanium oxide nanomaterials have been utilized to alter both photochemical (1000 nm > λ > 400 nm) and chemical heterogeneous reactivity with 2-chloroethyl ethyl sulfide (2-CEES). Synthesizing TiO2 nanomaterials in the presence of long-chain alkylphosphonic acids enhanced the visible light-driven oxidation of the thioether sulfur of 2-CEES. Photooxidation reaction rates of 99 and 168 µmol/g/h (quantum yields of 5.07 × 10-4 and 8.58 × 10-4 molecules/photon, respectively) were observed for samples made with two different alkylphosphonic acids (C14H29PO3H2 and C9H19PO3H2, respectively). These observations are correlated with (i) generation of new surface defects/states (i.e., oxygen vacancies) as a result of TiO2 grafting by alkylphosphonic acid that may serve as reaction active sites, (ii) better light absorption by assemblies of nanorods and nanowires in comparison to individual nanorods, (iii) surface area differences, and (iv) the exclusion of OH groups due to the surface functionalization with alkylphosphonic acids via Ti-O-P bonds on the TiO2. Alternatively, nanowire-form H2Ti2O5·H2O was produced and found to be capable of highly efficient hydrolysis of the carbon-chlorine (C-Cl) bond of 2-CEES in the dark with a reaction rate of 279.2 µmol/g/h due to the high surface area and chemical nature of the titanate structure.

Sulfonated 1,3-bis-(4-pyrid-yl)propane.

In the title compound, 4-[3-(3-sulfonato-pyridin-1-ium-4-yl)prop-yl]pyridin-1-ium-3-sulfonate, C(13)H(14)N(2)O(6)S(2), the mol-ecule is zwitterionic, with the sulfonic acid proton transfered to the basic pyridine N atom. Also, the structure adopts a butterfly-like conformation with the sulfonate groups on opposite sides of the 'wings'. The dihedral angle between the two pyridinium rings is 83.56 (7)°, and this results in the mol-ecule having a chiral conformation and packing. There is strong inter-molecular hydrogen bonding between the pyridinium H and sulfonate O atoms of adjoining mol-ecules. In addition, there are weaker inter-molecular C-H⋯O inter-actions.

catena-Poly[copper(II)-bis-(µ-2-ethyl-5-methyl-imidazole-4-sulfonato-κN,O:O)].

In the title compound, [Cu(C(6)H(9)N(2)O(3)S)(2)](n), the copper(II) ion sits on an inversion center and is chelated by the imidazole N and sulfonate O atoms of two ligands in equatorial positions. O atoms of adjacent mol-ecules coordinate in the axial positions. Jahn-Teller tetra-gonal distortion is evident in the coordination geometry [Cu-N and Cu-O equatorial distances of 1.971 (3) and 2.045 (2) Å, respectively, with a Cu-O axial distance of 2.433 (3) Å]. The structure is propagated by an infinite chain of eight-membered (Cu-O-S-O)(2) ring systems along the a axis. Only N-H⋯O hydrogen bonding exists between the chains.

The crystal structure of the deca-aluminum alkoxide cluster Al10O4(OH)8 L 14 (L = 1,1,1,3,3,3-hexa-fluoro-propan-2-olate).

In the title centrosymmetric cluster compound, hexa-kis-(µ2-1,1,1,3,3,3-hexa-fluoro-propan-2-olato)octa-kis-(1,1,1,3,3,3-hexa-fluoro-propan-2-olato)octa-µ2-hydroxido-di-µ4-oxido-di-µ3-oxido-deca-aluminium, [Al10(C3HF6O)14(OH)8O4] (C42H22Al10F84O26), there is a central µ4-OAl4 moiety, which has six edges of which three contain µ(O)-1,1,1,3,3,3-hexa-fluoro-propan-2-olate (L) ligands and two contain µ-OH groups each bridging two Al atoms along an edge. The sixth edge is occupied by a group containing a fifth aluminium atom [bis-µ(OH)-, µ3(O)-AlL]. This last µ3(O) group generates a centrosymmetric Al2O2 dimer, thus the µ3(O) atom is linked to two Al atoms in the asymmetric unit as well as a third Al atom through a center of inversion. Three of the hexa-fluoro-propyl groups of the C3HF6O- ligands are disordered and each was refined with two conformations with occupancies of 0.770 (3)/0.230 (3), 0.772 (3)/0.228 (3) and 0.775 (3)/0.225 (3). The five unique Al centers have coordination numbers varying from four to six with bond angles that show considerable distortions from regular geometry: for the four-coordinate atom, τ4' = 0.886, while three Al atoms are five-coordinate (τ5 values = 0.098, 1.028, and 0.338) and one is distorted six-coordinate with O-Al-O bond angles ranging from 74.22 (9) to 171.59 (12)°. The geometry about the central O atom in the OAl4 block is significantly distorted tetra-hedral (τ4' = 0.630) with Al-O-Al angles ranging from 95.50 (9) to 147.74 (13)°. The extended structure features numerous O-H⋯O, O-H⋯F, C-H⋯O and C-H⋯F hydrogen bonds and short F⋯F contacts.

µ-Methyl-ene-bis-[di-bromido(diethyl ether-κO)aluminium(III)]: crystal structure and chemical exchange in solution.

In the title compound, [Al2Br4(CH2)(C4H10O)2], the mol-ecule lies on a crystallographic twofold axis passing through the bridging C atom. Each AlIII atom is four-coordinate, being bonded to two bromide ions, bridging the CH2 group as well as the oxygen atom of a diethyl ether ligand in a slightly distorted tetra-hedral arrangement with angles ranging from 101.52 (8) to 116.44 (5)°. The Al-CH2-Al angle, 118.4 (2)°, is the smallest observed for a structure where this moiety is not part of a ring. In the crystal, weak C-H⋯Br inter-actions, characterized as R 2 2(12) rings, link the mol-ecules into ribbons in the [101] direction. The title compound is monomeric and coordinatively saturated in the solid state, as each aluminum is four-coordinate, but in solution the ether mol-ecules from either or both Al atoms can dissociate, and would be expected to rapidly exchange, and this is supported by NMR data.

Tetra-kis[µ2-1,1,1,3,3,3-hexa-fluoro-2-(tri-fluoro-meth-yl)propan-2-olato]tetra-kis-(µ3-2-methyl-propan-2-olato)octa-copper(I).

The title compound, [Cu8(C4H9O)4(C4F9O)4], crystallizes in the monoclinic space group, P21/n and contains a self-assembly of two C16H18Cu4F18O4 units linked by bridging tert-butyl groups [Cu-O bonds of length 2.3779 (15) and 2.4248 (15) Å], generating a centrosymmetric dimer. The asymmetrical unit, C16H18Cu4F18O4, contains an almost square-planar arrangement of the four Cu atoms linked by bridging tert-butyl and perfluorinated tert-butyl groups with Cu-Cu distances ranging from 2.7108 (4) to 2.7612 (4) Šand Cu -Cu-Cu angle values close to 90° [ranging from 89.459 (10)° to 90.025 (11)°]. These dimers are further linked by weak C-H⋯F and F⋯F inter-actions. As is commonly encountered in perfluorinated tert-butyl groups, one of the CF3 groups is disordered and was refined with two equivalent conformations with occupancies of 0.74 (3) and 0.26 (3).

Tetra-methyl-ammonium (Z)-N'-cyano-carbamimidate.

In the structure of the tetra-methyl ammonium salt of cyano-urea, C4H12N+·C2H2N3O-, the N-C and O-C bond distances in the cyano and keto groups are in the normal range for such a moieties at 1.1641 (18) and 1.2550 (16) Å. However, the bonds about the central C and N atoms are much shorter than would be expected for single bonds and indicate that there is considerable electron delocalization in the anion as was also found in the silver salt. The NH2 group is coplanar with the central N2CO core, in contrast with the nitrile group where the dihedral angle between the N-C-N and N2CO planes is 36.5 (3)°. The packing of the cations and anions in the unit cell involves N-H⋯O hydrogen bonds between anions characterized by an R 2 2(8) motif, as well as N-H⋯O hydrogen bonds between anions and C-H⋯O inter-actions between both cations and anions, forming an R 3 3(14) pattern.