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Reaction of thorium(IV) nitrate with 2-[(4-phenyl-1H-1,2,3-triazol-1-yl)meth­yl]pyridine (L) yielded (LH)2[Th(NO3)6] or (C14H13N4)2[Th(NO3)6] (1), instead of the expected mixed-ligand complex [Th(NO3)4L2], which was detected in the mass spectrum of 1. In the structure, the [Th(NO3)6]2− anions display an icosa­hedral coordination geometry and are connected by LH+ cations through C—H⋯O hydrogen bonds. The LH+ cations inter­act via N—H⋯N hydrogen bonds. Hirshfeld surface analysis indicates that the most important inter­actions are O⋯H/H⋯O hydrogen-bonding inter­actions, which represent a 55.2% contribution. [ABSTRACT FROM AUTHOR]

Reaction of thorium(IV) nitrate with 2-[(4-phenyl-1H-1,2,3-triazol-1-yl)meth­yl]pyridine (L) yielded (LH)2[Th(NO3)6] or (C14H13N4)2[Th(NO3)6] (1), instead of the expected mixed-ligand complex [Th(NO3)4L2], which was detected in the mass spectrum of 1. In the structure, the [Th(NO3)6]2- anions display an icosa­hedral coordination geometry and are connected by LH+ cations through C--H...O hydrogen bonds. The LH+ cations inter­act via N--H...N hydrogen bonds. Hirshfeld surface analysis indicates that the most important inter­actions are O...H/H...O hydrogen-bonding inter­actions, which represent a 55.2% contribution. [ABSTRACT FROM AUTHOR]

Effective thermal insulation materials rely on the fabrication of dense, ultra‐high‐temperature ceramics that can withstand harsh environments. Hafnium carbide‐based ceramics are one of the leading materials that have the potential to perform relatively well in high‐temperature oxidizing environments under mechanical loading due to their thermal and mechanical stability. In this study, we explore the effects of processing conditions to create dense, ablation‐resistant HfC–SiC composites with a fixed composition of HfC–20 wt.% SiC using a hot‐pressing method. Sintering pressure, temperature, and time were varied and the material's relative density, phase composition, morphology, microstructure, and hardness were investigated. Composite ceramics with 99% relative density relative to a theoretical value were created by hot pressing at 2100°C for 1 h at 50 MPa and displayed a fine microstructure with an average grain size of ∼5 µm and a Vickers hardness of 22.9 ±.8 GPa. The mass loss was determined using an oxyacetylene torch with cross‐section investigations of oxide surface formations and subsurface microstructural changes. These HfC–SiC samples developed a 410 nm hafnium oxide layer on the surface upon torch exposure and had an average calculated recession rate of.028 µm/s. [ABSTRACT FROM AUTHOR]

Herein, we report on a series of homoleptic [GaL3] and heteroleptic organometallic [GaMe2L] complexes of inactive quinolone antibiotics; nalidixic acid, oxolinic acid and norfloxacin with their antibacterial activity (MIC 0.024–0.781 μM) towards four multi-drug resistant strains of Klebsiella pneumoniae through complexation to gallium. [ABSTRACT FROM AUTHOR]

This paper describes a novel and simple method – direct reaction of lanthanoid metals with equimolar amounts of iodine and a formamidine under ultrasonication as an effective, metal‐based route to lanthanoid(III) diiodide formamidinates, namely I. N,N′‐Bis(2,6‐diisopropylphenyl)formamidinatodiiodidolanthanoid(III) complexes [Ln(DippForm)I2(thf)3] (Ln=La, 1, Ce, 2, Tb, 3, Ho, 4, Er, 5, Tm, 6); II. N,N′‐Bis(2,6‐diethylphenyl)formamidinatodiiodidolanthanoid(III) complexes [Ln(EtForm)I2(thf)3] (Ln=Ce, 7, Nd, 8, Gd, 9, Tb, 10, Dy, 11, Ho, 12, Er, 13, Lu, 14). III. N,N′‐bis(2,6‐dimethylphenyl)formamidinatodiiodidolanthanoid(III) complexes [Ln(XylForm)I2(thf)3] (Ln=Ce, 15, Nd, 16, Gd, 17, Tm, 18, Lu 19); IV. N,N′‐bis(phenyl)formamidinatodiiodidolanthanoid complexes [Ln(PhForm)I2(thf)3] (Ln=Nd, 20, Gd, 21, Er, 22). Compound [Ce(XylForm)2I(thf)2] (23) was also synthesized by the same method except the ratio of I2 to XylFormH was 1 : 4. Divalent N,N′‐bis(2,6‐diisopropylphenyl)formamidinato‐iodido‐lanthanoid(II) complexes [Eu(DippForm)I(thf)4] ⋅ thf (24), [Yb(DippForm)I(thf)3] ⋅ 2DippFormH (25), [Sm(DippForm)I(thf)4] ⋅ thf (26) have also been synthesized by direct reactions of the free metals, iodine and DippFormH. Interestingly, [Sm(DippForm)I2(thf)3] (27) was obtained by the oxidation of [Sm(DippForm)I(thf)4] ⋅ thf (26) on exposure to air. N,N′‐Bis(2,6‐dimethylphenyl)formamidinatoiodidosamarium(II) [Sm(XylForm)I(thf)3]n (28) was also prepared by direct reaction of Sm, iodine and XylFormH (mole ratio of I2: XylFormH=1 : 2). All products have been identified by X‐ray crystallography and all the trivalent complexes [Ln(Form)nI3‐n] (n=1 or 2) are stable to rearrangement. [ABSTRACT FROM AUTHOR]

Dinuclear silver formamidinates, [Ag2(DFForm)2(py)2] (1) (DFForm, N , N ′-bis(2,6-difluorophenyl)formamidinate, py = pyridine), [Ag2(m HForm)2(py)3] (2) and [Ag2(m HForm)2(CH3CN)2] (2a) (m HForm, N , N ′-bis(2,3,4,6-tetrafluorophenyl)formamidinate), [Ag2(p HForm)2(py)3] (3) (p HForm, N , N ′-bis(2,3,5,6-tetrafluorophenyl)formamidinate), [Ag2(PFForm)2(py)3] (4) (PFForm, N , N ′-bis(2,3,4,5,6-pentafluorophenyl)formamidinate) and [Ag2(DippForm)2]·1.25CH2Cl2 (5) (DippForm, N , N ′-bis(2,6-diisopropylphenyl)formamidinate), and polynuclear, mainly trinuclear, silver pyrazolates, [Ag3(Ph2pz)3]2 (6) (Ph2pz, 3,5-diphenylpyrazolate), [Ag(t Bu2pz)]4 (7) (t Bu2pz, 3,5-di- tert -butylpyrazolate), [Ag3(PhMepz)3] (8) (PhMepz, 3-methyl-5-phenylpyrazolate), [Ag3(Phtpz)3] (9) (Phtpz, 3-phenyl-5-(2-thienyl)pyrazolate), [Ag3(ttfpz)3] (10) (ttfpz, 3-(2-thienyl)-5-trifluoromethylpyrazolate) and [Ag2(Me2pz)(PPh3)4Cl] (11) (Me2pz, 3,5-dimethylpyrazolate) were successfully synthesized in good yield by treating silver(i) oxide with the corresponding formamidines (FormH) or pyrazoles (pzH) either in pyridine or acetonitrile. These rapid, easily handled and economical reactions are readily monitored by consumption of black silver oxide. All compounds are potential precursors in redox transmetallation reactions in the synthesis of lanthanoid and alkaline earth pyrazolate and formamidinate complexes. Dinuclear silver formamidinates and polynuclear, mainly trinuclear, silver pyrazolates were successfully synthesized in good yield by treating silver(i) oxide with the corresponding formamidines (FormH) or pyrazoles (pzH) either in pyridine or acetonitrile. [ABSTRACT FROM AUTHOR]

Unique outcomes have emerged from the redox transmetallation/ protolysis (RTP) reactions of europium metal with [Ag(C6F5)(py)] (py=pyridine) and pyrazoles (RR′pzH). In pyridine, a solvent not normally used for RTP reactions, the products were mainly EuII complexes, [Eu(RR′pz)2(py)4] (RR′pz=3,5‐diphenylpyrazolate (Ph2pz) 1; 3‐(2‐thienyl)‐5‐trifluoromethylpyrazolate (ttfpz) 2; 3‐methyl‐5‐phenylpyrazolate (PhMepz) 3). However, use of 3,5‐di‐tert‐butylpyrazole (tBu2pzH) gave trivalent [Eu(tBu2pz)3(py)2] 4, whereas the bulkier N,N′‐bis(2,6‐difluorophenyl)formamidine (DFFormH) gave divalent [Eu(DFForm)2(py)3] 5. In tetrahydrofuran (thf), the usual solvent for RTP reactions, C−F activation was observed for the first time with [Ag(C6F5)(py)] in such reactions. Thus trivalent [{Eu2(Ph2pz)4(py)4(thf)2(μ‐F)2}{Eu2(Ph2pz)4(py)2(thf)4(μ‐F)2}] (6), [Eu2(ttfpz)4(py)2(dme)2(μ‐F)2] (7), [Eu2(tBu2pz)4(dme)2(μ‐F)2] (8) were obtained from the appropriate pyrazoles, the last two after crystallization from 1,2‐dimethoxyethane (dme). Surprisingly 3,5‐dimethylpyrazole (Me2pzH) gave the divalent cage [Eu6(Me2pz)10(thf)6(μ‐F)2] (9). This has a compact ovoid core held together by bridging fluoride, thf, and pyrazolate ligands, the last including the rare μ4‐1η5(N2C3): 2η2(N,N′): 3κ(N): 4κ(N′) pyrazolate binding mode. With the bulky N,N′‐bis(2,6‐diisopropylphenyl)formamidine (DippFormH), which often favours C−F activation in RTP reactions, neither oxidation to EuIII nor C−F activation was observed and [Eu(DippForm)2(thf)2] (10) was isolated. By contrast, Eu reacted with Bi(C6F5)3 and Ph2pzH or tBu2pzH in thf without C−F activation, to give [Eu(Ph2pz)2(thf)4] (11) and [Eu(tBu2pz)3(thf)2] (12) respectively, the oxidation state outcomes corresponding to that for use of [Ag(C6F5)(py)] in pyridine. [ABSTRACT FROM AUTHOR]

Main‐group‐metal‐mediated transformations of imines have earned a valued place in the synthetic chemist's toolbox. Their versatility allows the simple preparation of various nitrogen containing compounds. This review will outline the early discoveries including metallation, addition/cyclisation and metathesis pathways, followed by the modern‐day use of imines in synthetic methodology. Recent advances in imine C−F activation protocols are discussed, alongside revisiting "classic" imine reactivity from a sustainable perspective. Developments in catalytic methods for hydroelementation of imines have been reviewed, highlighting the importance of s‐block metals in the catalytic arena. Whilst stoichiometric transformations in alternative reaction media such as deep eutectic solvents or water have been summarised. The incorporation of imines into flow chemistry has received recent attention and is summarised within. [ABSTRACT FROM AUTHOR]

The investigation of a novel gel‐casting system using a water‐soluble co‐polymer of isobutylene and maleic anhydride (trade name ISOBAM) to elucidate its nontraditional gelling mechanism is described. This system enables ceramic slurries to gel at low binder concentrations (0.3‐0.5 wt%), producing a dense, near‐net shaped green body with high solids loading, low organic content, low shrinkage, and moderate strength. The nature of the stabilizing bonds formed during gelation were investigated using Fourier‐transform infrared spectroscopy (FTIR), zeta potential, and rheological measurements which revealed that no covalent network was formed during gelation. It was concluded that the mechanism was based solely on weak interactions. As such, the ISOBAM casting system, and polymeric additive systems that behave similarly, represent a new class of near net‐shaped ceramic processing which could benefit a variety of applications, including ceramic additive manufacturing. [ABSTRACT FROM AUTHOR]