Cation-Cation Interaction in Np(V) Perchlorates and Their Electronic Absorption Spectra.

Four new Np(V) perchlorate complexes of the composition [NpO(HO)]ClO (orthorhombic) (), [(NpO)(ClO)(HO)]ClO·HO (), [(NpO)(UO)(HO)](ClO) (), and [(NpO)Cl(HO)]ClO·2HO () have been synthesized and structurally characterized. The structure of previously known monoclinic modification of NpOClO·4HO () has been determined at 100 K. The coordination environment of Np and U atoms in compounds - is pentagonal bipyramids.

Odd-Numbered Ring Cluster Tc(μ-O)Cl(OOCCCl): Synthesis, Crystal Structure, and Optical and Thermal Properties.

Herein, we report a method for the preparation of the first odd homometallic and heterovalent nine-centered Tc wheel, [Tc(μ-O)Cl(OOCCl)]. The synthesized compound represents the pioneering instance of such clusters among d elements and is the fourth instance observed across all metals. The ring was synthesized by a solvothermal method in a solution of technetium acid in trichloroacetic anhydride.

Effective self-assembly of 21- and 14-membered azamacrocycles condition-controlled cyclotrimerization or cyclodimerization of different thiosemicarbazide-based precursors.

A preparative synthesis of previously unknown 21- and 14-membered azamacrocycles acid-promoted cyclotrimerization or cyclodimerization of three readily available precursors, namely, 1-amino-6-hydroxy-4,6-dimethylhexahydropyrimidine-2-thione, 4-(4-oxopent-2-yl)thiosemicarbazide hydrazone, and 5,7-dimethyl-1,4,5,6-tetrahydro-3-1,2,4-triazepine-3-thione has been developed. A dramatic dependence of the selectivity of macrocyclization on the reaction conditions is demonstrated. The thermodynamic aspects of the reactions are discussed based on experimental data and DFT calculation results.

Crystal structure and Hirshfeld surface analysis of 1-[6-bromo-2-(3-bromo-phen-yl)-1,2,3,4-tetra-hydro-quinolin-4-yl]pyrrolidin-2-one.

This study presents the synthesis, characterization and Hirshfeld surface analysis of 1-[6-bromo-2-(3-bromo-phen-yl)-1,2,3,4-tetra-hydro-quinolin-4-yl]pyrrolidin-2-one, CHBrNO. In the title compound, the pyrrolidine ring adopts a distorted envelope configuration. In the crystal, mol-ecules are linked by inter-molecular N-H⋯O, C-H⋯O and C-H⋯Br hydrogen bonds, forming a three-dimensional network.

Synthesis of Technetium Carboxylates: Wheel-Like Octanuclear Clusters (Tc(μ-O)(RCOO), Where R = CF, CH)─Potential Nanobuilding Units for Tc-MOFs.

Herein, we studied the behavior of TcO in trifluoroacetic anhydride (TFAA) under visible light irradiation in situ by UV-vis spectroscopy. One carboxylate of Tc(VII) CFOTc () and two wheel-like carboxylate clusters of Tc(IV) Tc(μ-O)(CFCOO) (, ) and Tc(μ-O)(CHCOO) () were synthesized and analyzed using pXRD, TGA, UV-vis spectroscopy, and SCXRD techniques. According to SCXRD, it was found that Tc(IV) trifluoroacetate exists in two crystalline modifications.

Crystal structure and Hirshfeld surface analysis of 1-[6-bromo-2-(4-fluoro-phen-yl)-1,2,3,4-tetra-hydroquinolin-4-yl]pyrrolidin-2-one.

In the title compound, CHBrFNO, the pyrrolidine ring adopts an envelope conformation. In the crystal, mol-ecules are linked by inter-molecular N-H⋯O, C-H⋯O, C-H⋯F and C-H⋯Br hydrogen bonds, forming a three-dimensional network. In addition, C-H⋯π inter-actions connect mol-ecules into ribbons along the -axis direction, consolidating the mol-ecular packing.

Crystal structure and Hirshfeld surface analysis of ()-4-oxo-4-{phen-yl[(thio-phen-2-yl)meth-yl]amino}-but-2-enoic acid.

In the title compound, CHNOS, the mol-ecular conformation is stable with the intra-molecular O-H⋯O hydrogen bond forming a (7) ring motif. In the crystal, mol-ecules are connected by C-H⋯O hydrogen bonds, forming (8) chains running along the -axis direction. Cohesion of the packing is provided by weak van der Waals inter-actions between the chains.

Crystal structure and Hirshfeld surface analysis of ()-4-({[2-(benzo[]thio-phen-3-yl)cyclo-pent-1-en-1-yl]meth-yl}(phen-yl)amino)-4-oxobut-2-enoic acid.

In the title compound, CHNOS, the cyclopentene ring adopts an envelope conformation. In the crystal, mol-ecules are linked by C-H⋯π inter-actions, forming ribbons along the axis. Inter-molecular C-H⋯O hydrogen bonds connect these ribbons to each other, forming layers parallel to the (01) plane.

Application of the intramolecular Diels-Alder vinylarene (IMDAV) reaction for the synthesis of benzo-, carbocyclo-, thienothiopheneisoindolecarboxylic acids and its limitations.

Thienylallylamines, readily accessible from the corresponding thienyl aldehydes, react with maleic and trifluoromethylmaleic anhydrides leading to the formation of acids with a thieno[2,3-]isoindole core. The reaction sequence involves two successive steps: acylation of the nitrogen atom of the initial allylamine and the intramolecular Diels-Alder vinylarene (IMDAV) reaction. The scope and limitations of the proposed method were thoroughly investigated.

Crystal structure and Hirshfeld surface analysis of 10-hy-droxy-2-(4-meth-oxy-phen-yl)-3-oxo-2,3,3a,4,10,10a-hexa-hydro-1-9-thia-2-aza-cyclo-penta-[]fluorene-4-carb-oxy-lic acid dimethyl sulfoxide- monosolvate.

In the title compound, CHNOS·CDOS, the central six-membered ring has a slightly distorted boat conformation, while the fused pyrrolidine ring adopts an envelope conformation. These conformations are stabilized by O-H⋯O hydrogen bonds between the main compound and solvent mol-ecules. In addition, intra-molecular C-H⋯O hydrogen bonds in the main mol-ecule form two (6) rings.

Crystal structure of [1,3-bis-(2,4,6-tri-methyl-phen-yl)imidazolidin-2-yl-idene]di-chlorido-(2-{[(2-methoxyeth-yl)(meth-yl)amino]-meth-yl}benzyl-idene)ruth-en-ium.

The title compound, [RuCl(CHNO)], is an example of a new generation of ,-dialkyl ruthenium catalysts with an N-Ru coordination bond as part of a six-membered chelate ring. The Ru atom has an Addison τ parameter of 0.244, which indicates a geometry inter-mediate between square-based pyramidal and trigonal-bipyramidal.

Influence of the organic cation on the formation of hexahalotechnetates: X-ray, thermal and comparative analyses of non-covalent interactions.

In this work, we have reviewed non-covalent interactions in technetium hexahalide compounds and obtained eight new compounds of the CatTcHal type, where Cat = dimethylammonium, tetramethylammonium, caffeinium, benzothiazolium, nicotinamidium, and pyrazolium, and Hal = Cl, Br. SCXRD studies were carried out for new compounds. In some compounds, halide anions and/or crystallization water were present.

Domino Three-Component -Acylation/[4 + 2] Cycloaddition/Alder-ene Synthesis of Polysubstituted Benzo[]isoindole-4-carboxylic Acids.

Diversely substituted, partially saturated benzo[]isoindole-4-carboxylic acids were synthesized by a new three-component reaction (3CR) starting from cinnamic amines (3-arylallylamines), maleimides, and maleic anhydride. The process consists of -acylation of the amines by maleic anhydride, intramolecular [4 + 2] cycloaddition in vinylarenes (the IMDAV reaction), and the concluding Alder-ene reaction between Diels-Alder intermediates and maleimides. All of the reaction steps proceed in a highly regio- and stereoselective manner, furnishing five adjacent chiral centers and leading to a single diastereoisomer of the title compound.

Synthesis, crystal structure and Hirshfeld surface analysis of bis-(caffeinium) hexa-chlorido-platinum(IV) in comparison with some related compounds.

The mol-ecular and crystal structure of the title compound, (CHNO)[PtCl], synthesized from hexa-chloro-platinic acid and caffeine in methanol, was studied by single-crystal X-ray diffraction. The caffeinium cations form a double layer hydrogen bonds and π-stacking inter-actions. The Hirshfeld surface analysis showed that the largest contribution to the crystal packing is made by H⋯H (31.

Crystal structures and Hirshfeld surface analyses of ,-di-methyl-acetamide-1-(dimethyl-λ-aza-nyl-idene)ethan-1-ol tribromide (1/1), ,-di-methyl-acetamide-1-(dimethyl-λ-aza-nyl-idene)ethan-1-ol di-bromido-iodate (1/1) and ,-di-methyl-acetamide-1-(dimethyl-λ-aza-nyl-idene)ethan-1-ol di-chlorido-iodate (1/1).

In the title compounds, ,-di-methyl-acetamide-1-(dimethyl-λ-aza-nyl-idene)ethan-1-ol tribromide (1/1), CHNO·CHNO·Br or [(CHNO)·(CHNO)](Br), (), ,-di-methyl-acetamide-1-(dimethyl-λ-aza-nyl-idene)ethan-1-ol di-bromido-iodate (1/1), CHNO·CHNO·BrI or [(CHNO)·(CHNO)](BrI), (), and ,-di-methyl-acetamide-1-(dimethyl-λ-aza-nyl-idene)ethan-1-ol di-chlorido-iodate (1/1), CHNO·CHNO·ClI or [(CHNO)·(CHNO)]·(ClI), (), all the anions are almost linear in geometry and all the cations, except for the methyl H atoms, are essentially planar. In the crystal structure of (), the cations are linked by pairs of C-H⋯O hydrogen bonds, forming inversion dimers with an (8) ring motif. These dimers also exhibit O-H⋯O hydrogen bonding.

Intramolecular Re···O Nonvalent Interactions as a Stabilizer of the Polyoxorhenate(VII).

The first polyoxorhenate(VII) compound, pyrazolium polyoxorhenate ((CNH)ReO), and two new rhenium(VII) and technetium(VII) salts have been synthesized and studied. The structure of TcO has been reinvestigated. The [ReO] polyoxoanion contains four Re(VII) atoms: one with an octahedral environment and three with a tetrahedral environment.

Mixed-Valence Np/An Molybdate Complexes with Single-Charge Outer-Sphere Cations.

Five new mixed-valence Np/An molybdates of the composition [C(NH)][(NpO)(NpO)(MoO)(HO)]·HO (), [C(NH)][(NpO)(NpO)(MoO)(HO)]·3HO (), Na[(NpO)(PuO)(MoO)(HO)]·HO (), Na[(NpO)(UO)(MoO)]·13HO (), and LiNa[(NpO)(NpO)(MoO)(HO)]·4HO () have been synthesized and structurally characterized. The coordination polyhedra of the Np and An atoms in compounds - are pentagonal bipyramids. The basis of structures - is anionic layers of the composition [(NpO)(AnO)(MoO)(HO)].

Crystal structure and Hirshfeld surface analysis of (2 ,2 ,2 ,2 )-2,2,5-trimethyl-2-(2,2,2-tri-fluoro-acet-yl)-5-aza-2(2,6)-piperidina-1,3(2,5)-di-furana-cyclo-hexa-phan-2-one.

The title compound, CHFNO, features a main twelve-membered difuryl ring with which the furan rings make dihedral angles of 76.14 (5) and 33.81 (5)°.

Microbial methane cycling in sediments of Arctic thermokarst lagoons.

Thermokarst lagoons represent the transition state from a freshwater lacustrine to a marine environment, and receive little attention regarding their role for greenhouse gas production and release in Arctic permafrost landscapes. We studied the fate of methane (CH ) in sediments of a thermokarst lagoon in comparison to two thermokarst lakes on the Bykovsky Peninsula in northeastern Siberia through the analysis of sediment CH concentrations and isotopic signature, methane-cycling microbial taxa, sediment geochemistry, lipid biomarkers, and network analysis. We assessed how differences in geochemistry between thermokarst lakes and thermokarst lagoons, caused by the infiltration of sulfate-rich marine water, altered the microbial methane-cycling community.

Influence of Substituents in a Six-Membered Chelate Ring of HG-Type Complexes Containing an N→Ru Bond on Their Stability and Catalytic Activity.

An efficient approach to the synthesis of olefin metathesis HG-type catalysts containing an N→Ru bond in a six-membered chelate ring was proposed. For the most part, these ruthenium chelates can be prepared easily and in high yields based on the interaction between 2-vinylbenzylamines and (the common precursor for Ru-complex synthesis). It was demonstrated that the increase of the steric volume of substituents attached to the nitrogen atom and in the α-position of the benzylidene fragment leads to a dramatic decrease in the stability of the target ruthenium complexes.

New Preparative Approach to Purer Technetium-99 Samples-Tetramethylammonium Pertechnetate: Deep Understanding and Application of Crystal Structure, Solubility, and Its Conversion to Technetium Zero Valent Matrix.

Tc is one of the predominant fission products of U and an important component of nuclear industry wastes. The long half-life and specific activity of Tc (212,000 y, 0.63 GBq g) makes Tc a hazardous material.

Thiourea as a Stabilizer of Reduced Forms of Technetium─Tc(III) and Tc(IV): Experimental and Theoretical Studies of Complexes.

This paper presents synthetic methods for the preparation of Tc(III) and Tc(IV) coordination compounds with thiourea. We have shown that the main product of the synthesis is the complex [TcTuX]X, (Tu = (NH)CS, X = Cl, Br) and not [TcTu]Cl·4HO, as previously thought. Tu[TcX]X·3HO is the main technetium-containing byproduct of the reaction.

Different Modes of Acid-Promoted Cyclooligomerization of 4-(4-Thiosemicarbazido)butan-2-one Hydrazone: 14-Membered versus 28-Membered Polyazamacrocycle Formation.

Unprecedented self-assembly of a novel 14-membered cyclic bis-thiosemicarbazone or/and a 28-membered cyclic tetrakis-thiosemicarbazone upon acid-promoted cyclooligomerization of 4-(4-thiosemicarbazido)butan-2-one hydrazone has been discovered. A thorough study of the influence of various factors on the direction of macrocyclization provided the optimal conditions for the highly selective formation of each of the macrocycles in excellent yields. Plausible pathways for macrocyclizations have been discussed.

Novel Synthesis Methods of New Imidazole-Containing Coordination Compounds Tc(IV, V, VII)-Reaction Mechanism, Xrd and Hirshfeld Surface Analysis.

In this work, we have proposed two new methods for the synthesis of [TcOL] (where L = imidazole (Im), methylimidazole (MeIm)) complexes using thiourea (Tu) and Sn(II) as the reducing agents. The main and by-products of the reactions were determined, and possible reaction mechanisms were proposed. We have shown that the reduction of Tc(VII) with thiourea is accompanied by the formation of the Tc(III) intermediate and further oxidation to Tc(V).

Nucleophilic Substitution Reactions in the [BH] Anion in the Presence of Lewis Acids.

As a result of our study on the interaction between the octahydrotriborate anion with nucleophiles (Nu = THF, PhP, PhP-(CH)-PPh (dppe), PhAs, EtN, PhNH, CHN, CHCN, PhCHCN)) in the presence of a wide range of Lewis acids (Ti(IV), Hf(IV), Zr(IV), Al, Cu(I), Zn, Mn(II), Co(II) halides and iodine), a number of substituted derivatives of the octahydrotriborate anion [BHNu] are obtained. It is found that the use of TiCl, AlCl, ZrCl, HfCl, CuCl and iodine leads to the highest product yields. In this case, it is most likely that the reaction proceeds through the formation of an intermediate [BH-HMXn], which was detected by NMR spectroscopy.