Dorzolamide hydro­chloride: an anti­glaucoma agent

Dorzolamide hydro­chloride [systematic name: (4S)‐trans‐4‐ethyl­ammonio‐6‐methyl‐5,6‐dihydro‐4H‐thieno[2,3‐b]thio­pyran‐2‐sulfonamide 7,7‐dioxide chloride], C₁₀H₁₇N₂O₄S₂⁺·Cl⁻, belongs to a class of drugs called carbonic anhydrase inhibitors. The ethyl­ammonio side chain is in an extended conformation and is protonated at the N atom, which is hydrogen bonded to the Cl⁻ anion. The dihedral angle between the planes of the thio­phene ring and the sulfonamide group is 80.7 (1)°. A comparison is made with the dorzolamide bound in human carbonic anhydrase in the solid state. Hydrogen bonding is mediated by Cl⁻ anions, resulting in indirect connectivity between the mol­ecules.     

The iso­thio­cyanate complex of tri­phenyl­borane forms an unusual coordination polymer with [K(18‐crown‐6)]+, both in the solid state and in solution

The title salt, (1,4,7,10,13,16‐hexa­oxa­cyclo­octa­decane‐κ⁶O)[(iso­thio­cyanato)­tri­phenyl­borato‐κS]­potassium(I), [K(C₁₉H₁₅BNS)(C₁₂H₂₄O₆)] or [K(SCNBPh₃)(18‐crown‐6)], where 18‐crown‐6 is 1,4,7,10,13,16‐hexaoxa­cyclo­octa­decane and [SCNBPh₃]⁻ is the (iso­thio­cyanato)­tri­phenyl­borate anion, exhibits a supramol­ecular structure that is best described as a helical coordination polymer or molecular screw. This unusual supramolecular structure is based on a framework in which the SCN⁻ ion bridges the chelated K⁺ ion and the B atom of BPh₃ in a μ₂ fashion. The X‐ray crystal structure of the title salt has been determined at 100 (1) and 293 (2) K. The K⁺ ion exhibits axial ligation by the S atom of the [SCNBPh₃]⁻ anion, with a K—S distance of 3.2617 (17) Å (100 K). The trans‐axial ligand is an unexpected η²‐bound C=C bond of a phenyl group (meta‐ and para‐C atoms) that belongs to the BPh₃ moiety of a neighboring mol­ecule. The K—C bond distances span the range 3.099 (3)–3.310 (3) Å (100 K) and are apparently retained in CDCl₃ solution (as evidenced by ¹³C NMR spectroscopy). By virtue of the latter interaction, the supramolecular structure is a helical coordination polymer, with the helix axis parallel to the b axis of the unit cell. IR spectroscopy and semi‐empirical molecular orbital (AM1) calculations have been used to investigate further the electronic structure of the [SCNBPh₃]⁻ ion.     

1,3,5‐Triamino‐1,3,5‐trideoxy‐cis‐inositol,a Ligand with a Remarkable Versatility for Metal Ions. Part XIII

The two neutral complexes [Re(CO)₃(H₋₁taci)] ( 1 ) and [ReO₃(H₋₁taci)] ( 2 ) (taci=1,3,5‐triamino‐1,3,5‐trideoxy‐cis‐inositol) were synthesized from the conventional Re^I and Re^VII precursors (Et₄N)₂[ReBr₃(CO)₃] and [ReO₃(OSnMe₃)]. The crystal structures of 1 and 2 , which were determined by single crystal X‐ray analysis, are virtually isomorphous. Both compounds crystallize in the orthorhombic space group Pnma, Z=4; 1 : a=14.806(3), b=8.466(2), c=9.781(2) Å, 2 : a=13.050(2), b=8.732(1), c=9.061(1) Å. In both complexes, the monodeprotonated H₋₁taci ligand is bonded to the Re center in an N,O,N‐coordination mode. The resulting molecular C_s symmetry is retained in the crystal structure and confirmed by IR spectroscopy of solid‐state samples. The observed binding mode of the ligand is discussed in terms of steric and electronic effects.     

Nimustine hydrochloride: the first crystal structure determination of a 2‐chloroethyl‐N‐nitrosourea hydrochloride derivative by X‐ray powder diffraction and solid‐state NMR

Nimustine hydrochloride [systematic name: 4‐amino‐5‐({[N‐(2‐chloroethyl)‐N‐nitrosocarbamoyl]amino}methyl)‐2‐methylpyrimidin‐1‐ium chloride], C₉H₁₄ClN₆O₂⁺·Cl⁻, is a prodrug of CENU (chloroethylnitrosourea) and is used as a cytostatic agent in cancer therapy. Its crystal structure was determined from laboratory X‐ray powder diffraction data. The protonation at an N atom of the pyrimidine ring was established by solid‐state NMR spectroscopy.     

Crystallographic characterization of the first reported crystalline form of the potent hallucinogen (R)‐2‐amino‐1‐(8‐bromobenzo[1,2‐b;5,4‐b′]difuran‐4‐yl)propane or `bromodragonfly': the 1:1 anhydrous proton‐transfer compound with 3,5‐dinitrosalicylic acid

The 1:1 proton‐transfer compound of the potent substituted amphetamine hallucinogen (R)‐2‐amino‐1‐(8‐bromobenzo[1,2‐b;5,4‐b′]difuran‐4‐yl)propane (common trivial name `bromodragonfly') with 3,5‐dinitrosalicylic acid, namely 1‐(8‐bromobenzo[1,2‐b;5,4‐b′]difuran‐4‐yl)propan‐2‐aminium 2‐carboxy‐4,6‐dinitrophenolate, C₁₃H₁₃BrNO₂⁺·C₇H₃N₂O₇⁻, forms hydrogen‐bonded cation–anion chain substructures comprising undulating head‐to‐tail anion chains formed through C(8) carboxyl–nitro O—H...O associations and incorporating the aminium groups of the cations. The intrachain cation–anion hydrogen‐bonding associations feature proximal cyclic R₃³(8) interactions involving both an N⁺—H...O_phenolate and the carboxyl–nitro O—H...O associations and aromatic π–π ring interactions [minimum ring centroid separation = 3.566 (2) Å]. A lateral hydrogen‐bonding interaction between the third aminium H atom and a carboxyl O‐atom acceptor links the chain substructures, giving a two‐dimensional sheet structure. This determination represents the first of any form of this compound and is in the (R) absolute configuration. The atypical crystal stability is attributed both to the hydrogen‐bonded chain substructures provided by the anions, which accommodate the aminium proton‐donor groups of the cations and give crosslinking, and to the presence of the cation–anion aromatic ring π–π interactions.     

A novel two‐dimensional zinc(II) coordination polymer with 6‐mercaptonicotinic acid

The novel title Zn^II coordination polymer, poly[bis(μ‐6‐thioxo‐1,6‐dihydropyridine‐3‐carboxylato‐κ²S:O)zinc(II)], [Zn(C₆H₄NO₂S)₂]_n, consists of two crystallographically independent zinc centers and two 6‐mercaptonicotinate (Hmna⁻) ligands. Each Zn^II atom is four‐coordinated and lies at the center of a distorted tetrahedral ZnS₂O₂ coordination polyhedron, bridged by four Hmna⁻ ligands to form a two‐dimensional (4,4)‐network. Each Hmna⁻ ion acts as a bridging bidentate ligand, coordinating to two Zn^II atoms through the S atom and a carboxyl O atom. The metal centers reside on twofold rotation axes. The coordination mode of the S atoms and N—H...O hydrogen‐bonding interactions between the protonated N atoms and the uncoordinated carboxyl O atoms give the extended structure a wavelike form.     

Synthesis and ab initio X‐ray powder diffraction structure of the new alkali and alkali earth metal borate NaCa(BO3)

A sodium calcium borate, NaCaBO₃, has been synthesized by the solid‐state reaction method and the structure solved from X‐ray powder diffraction data. The compound crystallizes in space group Pmmn and has a desired structure type containing isolated planar BO₃³⁻ anions. Mixed occupancy is found to exist in the Ca site, with partial replacement by Na. One Ca/Na mixed atom and one Na atom are at sites with mm2 symmetry, and a second Ca/Na mixed atom, an Na atom, two B and two O atoms are on mirror planes.     

Supramolecular framework in catena‐poly[[(nitrato‐κO)silver(I)]‐μ‐(R,S)‐2‐(pyridin‐4‐ylsulfinyl)pyrimidine‐κ3N,O:N′]

In the title complex, [Ag(NO₃)(C₉H₇N₃OS)]_n, η¹:η¹:η¹:μ₂‐bridging 2‐(pyridin‐4‐ylsulfinyl)pyrimidine (pypmSO) ligands with opposite chiralities are alternately arranged to link the Ag^I cations through two N atoms and one sulfinyl O atom of each ligand, leading to an extended zigzag coordination chain structure along the [01] direction. An FT–IR spectroscopic study shows a decreased stretching frequency for the η¹‐O‐bonded S=O group compared with that of the free ligand. The parallel chains are arranged and interconnected via O(S=O)...π(pyridine/pyrimidine) and C—H(pyridine)...O(NO₃⁻) interactions to furnish a layer almost parallel to the ac plane. Along the b axis, the layers are stacked and stabilized through anion(NO₃⁻)...π(pyrimidine) interactions to form a three‐dimensional supramolecular framework. The ligand behaviour of the new diheterocyclic sulfoxide and the unconventional O(S=O)...π(pyridine/pyrimidine) and anion(NO₃⁻)...π(pyrimidine) interactions in the supramolecular assembly of the title complex are presented.     

Two polymorphs and the diethylammonium salt of the barbiturate eldoral

Polymorph (Ia) of eldoral [5‐ethyl‐5‐(piperidin‐1‐yl)barbituric acid or 5‐ethyl‐5‐(piperidin‐1‐yl)‐1,3‐diazinane‐2,4,6‐trione], C₁₁H₁₇N₃O₃, displays a hydrogen‐bonded layer structure parallel to (100). The piperidine N atom and the barbiturate carbonyl group in the 2‐position are utilized in N—H...N and N—H...O=C hydrogen bonds, respectively. The structure of polymorph (Ib) contains pseudosymmetry elements. The two independent molecules of (Ib) are connected via N—H...O=C(4/6‐position) and N—H...N(piperidine) hydrogen bonds to give a chain structure in the [100] direction. The hydrogen‐bonded layers, parallel to (010), formed in the salt diethylammonium 5‐ethyl‐5‐(piperidin‐1‐yl)barbiturate [or diethylammonium 5‐ethyl‐2,4,6‐trioxo‐5‐(piperidin‐1‐yl)‐1,3‐diazinan‐1‐ide], C₄H₁₂N⁺·C₁₁H₁₆N₃O₃⁻, (II), closely resemble the corresponding hydrogen‐bonded structure in polymorph (Ia). Like many other 5,5‐disubstituted derivatives of barbituric acid, polymorphs (Ia) and (Ib) contain the R₂²(8) N—H...O=C hydrogen‐bond motif. However, the overall hydrogen‐bonded chain and layer structures of (Ia) and (Ib) are unique because of the involvement of the hydrogen‐bond acceptor function in the piperidine group.     

K3TaF8 from laboratory X‐ray powder data

The crystal structure of tripotassium octafluoridotantalate, K₃TaF₈, determined from laboratory powder diffraction data by the simulated annealing method and refined by total energy minimization in the solid state, is built from discrete potassium cations, fluoride anions and monocapped trigonal–prismatic [TaF₇]²⁻ ions. All six atoms in the asymmetric unit are in special positions of the P6₃mc space group: the Ta and one F atom in the 2b (3m) sites, the K and two F atoms in the 6c (m) sites, and one F atom in the 2a (3m) site. The structure consists of face‐sharing K₆ octahedra with a fluoride anion at the center of each octahedron, forming chains of composition [FK₃]²⁺ running along [001] with isolated [TaF₇]²⁻ trigonal prisms in between. The structure of the title compound is different from the reported structure of Na₃TaF₈ and represents a new structure type.     

Antidiarrhetic loperamide hydrochloride

Single crystals of the anhydrous form of the title compound {systematic name: 1‐[3‐(dimethylcarbamoyl)‐3,3‐diphenylpropyl]‐4‐hydroxy‐4‐(4‐chlorophenyl)piperidin‐1‐ium chloride}, C₂₉H₃₄ClN₂O₂⁺·Cl⁻, were obtained by diffusion of acetone into a solution in 2‐propanol. In the structure, N—H...Cl⁻ and O—H...Cl⁻ hydrogen bonds connect neighbouring molecules and chloride anions to form chains along the c‐axis direction. Neighbouring chains along the b‐axis direction are connected by intermolecular C—H...Cl⁻ contacts, defining layers parallel to the (100) planes. The layers are connected by weak intermolecular C—H...Cl interactions only, which may account for the plate‐like shape of the crystals.     

Structure of Hexakis(imidazole)nickel(II) Nitrate Water Solvate:[Ni(Im)_6] (NO_3)_2·4H_2O

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Metal Oxide Nanostructures Generated from In Situ Sacrifice of Zinc in Bimetallic Textures as Flexible Ni/Fe Fast Battery Electrodes

An “in situ sacrifice” process was devised in this work as a room‐temperature, all‐solution processed electrochemical method to synthesize nanostructured NiO_x and FeO_x directly on current collectors. After electrodepositing NiZn/FeZn bimetallic textures on a copper net, the zinc component is etched and the remnant nickel/iron are evolved into NiO_x and FeO_x by the “in situ sacrifice” activation we propose. As‐prepared electrodes exhibit high areal capacities of 0.47 mA h cm⁻² and 0.32 mA h cm⁻², respectively. By integrating NiO_x as the cathode, FeO_x as the anode, and poly(vinyl alcohol) (PVA)‐KOH gel as the separator/solid‐state electrolyte, the assembled quasi‐solid‐state flexible battery delivers a volumetric capacity of 6.91 mA h cm⁻³ at 5 mA cm⁻², along with a maximum energy density of 7.40 mWh cm⁻³ under a power density of 0.27 W cm⁻³ and a maximum tested power density of 3.13 W cm⁻³ with a 2.17 mW h cm⁻³ energy density retention. Our room‐temperature synthesis, which only consumes minute electricity, makes it a promising approach for large‐scale production. We also emphasize the in situ sacrifice zinc etching process used in this work as a general strategy for metal‐based nanostructure growth for high‐performance battery materials.     

Hydrogen‐Bonding in Cyclic 2‐(3‐Oxo‐3‐phenylpropyl)‐Substituted 1,3‐Diketones: 17O‐NMR Spectra and X‐Ray Structure Determination

Structures of cyclic 2‐(3‐oxo‐3‐phenylpropyl)‐substituted 1,3‐diketones 4a – c were determined by ¹⁷O‐NMR spectroscopy and X‐ray crystallography. In CDCl₃ solution, compounds 4a – c form an eight‐membered‐ring with intramolecular H‐bonding between the enolic OH and the carbonyl O(11)‐atom of the phenylpropyl group, as demonstrated by increased shielding of specifically labeled 4a – c in the ¹⁷O‐NMR spectra (Δδ(¹⁷O(11))=36 ppm). In solid state, intermolecular H‐bonding was observed instead of intramolecular H‐bonding, as evidenced by the X‐ray crystal‐structure analysis of compound 4b . Crystals of compound 4b at 293 K are monoclinic with a=11.7927 (12) Å, b=13.6230 (14) Å, c=9.8900 (10) Å, β=107.192 (2)°, and the space group is P2₁/c with Z=4 (refinement to R=0.0557 on 2154 independent reflections).     

rac‐3‐Benzoyl‐2‐methylpropionic acid and its organic salts: possibilities of Yang photocyclization in crystals

The analysis of the crystal structures of rac‐3‐benzoyl‐2‐methylpropionic acid, C₁₁H₁₂O₃, (I), morpholinium rac‐3‐benzoyl‐2‐methylpropionate monohydrate, C₄H₁₀NO⁺·C₁₁H₁₁O₃⁻·H₂O, (II), pyridinium [hydrogen bis(rac‐3‐benzoyl‐2‐methylpropionate)], C₅H₆N⁺·(H⁺·2C₁₁H₁₁O₃⁻), (III), and pyrrolidinium rac‐3‐benzoyl‐2‐methylpropionate rac‐3‐benzoyl‐2‐methylpropionic acid, C₄H₁₀N⁺·C₁₁H₁₁O₃⁻·C₁₁H₁₂O₃, (IV), has enabled us to predict and understand the behaviour of these compounds in Yang photocyclization. Molecules containing the Ar—CO—C—C—CH fragment can undergo Yang photocyclization in solvents but they can be photoinert in the crystalline state. In the case of the compounds studied here, the long distances between the O atom of the carbonyl group and the γ‐H atom, and between the C atom of the carbonyl group and the γ‐C atom preclude Yang photocyclization in the crystals. Molecules of (I) are deprotonated in a different manner depending on the kind of organic base used. In the crystal structure of (III), strong centrosymmetric O...H...O hydrogen bonds are observed.     

Highly Active Hydrogen-rich Photothermal Reverse Water Gas Shift Reaction on Ni/LaInO3 Perovskite Catalysts with Near-unity Selectivity

Photo-assisted reverse water gas shift (RWGS) reaction is regarded green and promising in controlling the reaction gas ratio in Fischer Tropsch synthesis. But it is inclined to produce more byproducts in high H₂ concentration condition. Herein, LaInO₃ loaded with Ni-nanoparticles (Ni NPs) was designed to obtain an efficient photothermal RWGS reaction rate, where LaInO₃ was enriched with oxygen vacancies to roundly adsorbing CO₂ and the strong interaction with Ni NPs endowed the catalysts with powerful H₂ activity. The optimized catalyst performed a large CO yield rate (1314 mmol g_Ni⁻¹ h⁻¹) and ≈100 % selectivity. In situ characterizations demonstrated a COOH* pathway of the reaction and photoinduced charge transfer process for reducing the RWGS reaction active energy. Our work provides valuable insights on the construction of catalysts concerning products selectivity and photoelectronic activating mechanism on CO₂ hydrogenation.     

Positional and compositional disorder in a ruthenium(II) piano‐stool complex

In (η⁶‐p‐cymene)(difluorophosphinato‐κO){2‐[(1H‐pyrazol‐1‐yl)methyl‐κN²]pyridine‐κN}ruthenium(II) 0.85‐hexafluorophosphate 0.15‐tetrafluoroborate, [Ru(PO₂F₂)(C₁₀H₁₄)(C₉H₉N₃)](PF₆)_0.85(BF₄)_0.15, (I), the [PO₂F₂]⁻ ligand exhibits positional disorder due to one F atom and one O atom sharing the same two positions related by a mirror reflection across the O—P—F plane. The correct composition of this coordinated anion was successfully determined to be [PO₂F₂]⁻ by refining the complex with various tetrahedral anions in which terminal atoms have similar atomic form factors. The noncoordinated counter‐ion is compositionally disordered between [PF₆]⁻ and [BF₄]⁻. The difficulty in determining the correct composition of this anion illustrates the importance of a crystallographer remaining impartial and open to encountering unexpected moieties in the process of elucidating a structure.     

Poly[bis(μ3‐5′‐carboxy‐2,2′‐bipyridine‐5‐carboxylato‐κ4O:N,N′:O′)lead(II)]

The title compound, [Pb(C₁₂H₇N₂O₄)₂]_n, obtained by reaction of Pb(NO₃)₂ and 2,2′‐bipyridine‐5,5′‐dicarboxylic acid (H₂bptc) under hydrothermal conditions, has a structure in which the unique Pb^II cation sits on a twofold axis and is octa‐coordinated by four O‐atom donors from four Hbptc⁻ ligands and four N‐atom donors from two Hbptc⁻ ligands in a distorted dodecahedral geometry. With each Pb^II cation connected to six Hbptc⁻ ligands and each Hbptc⁻ ligand bridging three Pb^II cations, a three‐dimensional polymeric structure is formed. From a topological point of view, the three‐dimensional net is binodal, with six‐connected (the Pb^II cation) and three‐connected (the Hbptc⁻ ligand) nodes, resulting in a distorted rutile (4².8)₂(4⁴8⁹12²) topology.     

Synthesis and Crystal Structure of α‐ThTe3

The binary thorium tritelluride, α‐ThTe₃, was synthesized by solid‐state methods at 1223 K. From a single‐crystal X‐ray diffraction study the material crystallizes in the TiS₃ structure type with two formula units in space group C²_2h–P2₁/m of the monoclinic system in a cell with lattice constants a = 6.1730 (4) Å, b = 4.3625(3) Å, c = 10.4161(6) Å, and β = 97.756(3)° (at 100 K). The asymmetric unit of this compound comprises one Th atom and three Te atoms each with site symmetry m. Each Th atom is coordinated to eight Te atoms in a bicapped trigonal‐pyramidal arrangement. Th–Te distances range from 3.1708(4) Å to 3.2496(6) Å. The structure features a Te–Te interaction 2.7631(8) Å in length, which is typical for a Te–Te single bond. Thus α‐ThTe₃ may be charge balanced and formulated as Th⁴⁺Te^2–Te₂^2–.     

l‐Prolinium picrate and 2‐methyl­pyridinium picrate

In the structure of l ‐prolinium picrate, C₅H₁₀NO₂⁺·C₆H₂N₃O₇⁻, the C^γ atom of the pyrrolidine ring has conformational disorder. Both the major and minor conformers of the pyrrolidine ring adopt conformations inter­mediate between a half‐chair and an envelope. Both the cation and anion are packed through chelated three‐centred N—H⋯O hydrogen bonds. The prolinium cation connects two different picrate anions, leading to an infinite chain running along the b axis. In 2‐methyl­pyridinium picrate, C₆H₈N⁺·C₆H₂N₃O₇⁻, the cations and anions are packed separately along the a axis and are inter­connected by N—H⋯O hydrogen bonds. Intra­molecular contacts between phenolate O atoms and adjacent nitro groups are identified in both structures. A graph‐set motif of R₁²(6) is observed in both structures.