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The molecular structure of tert -butyl 3,6-diiodocarbazole-9-carboxylate, C 17 H 15 I 2 NO 2 , features a nearly planar 13-membered carbazole ring with C—I bond lengths of 2.092 (4) and 2.104 (4) Å. The carbamate group has key bond lengths of 1.404 (6) Å (N—C), 1.330 (5) Å (O—C), and 1.201 (6) Å (C=O). The crystal contains intermolecular π–π interactions, as well as both type I and type II intermolecular I...I interactions. 

This paper compares variations on a structure model derived from an X-ray diffraction data set from a solid solution of chalcogenide derivatives of cis -1,2-bis(diphenylphosphanyl)ethylene, namely, 1,2-(ethene-1,2-diyl)bis(diphenylphoshpine sulfide/selenide), C 26 H 22 P 2 S 1.13 Se 0.87 . A sequence of processes are presented to ascertain the composition of the crystal, along with strategies for which aspects of the model to inspect to ensure a chemically and crystallographically realistic structure. Criteria include mis-matches between F obs 2 and F calc 2 , plots of | F obs | vs | F calc |, residual electron density, checkCIF alerts, pitfalls of the OMIT command used to suppress ill-fitting data, comparative size of displacement ellipsoids, and critical inspection of interatomic distances. Since the structure is quite small, solves easily, and presents a number of readily expressible refinement concepts, we feel that it would make a straightforward and concise instructional piece for students learning how to determine if their model provides the best fit for the data and show students how to critically assess their structures. 

A novel synthesis of diphenyl(2-thienyl)phosphine, along with its’ oxide, sulfide and selenide derivatives, is reported here. These phosphines have been characterized by NMR, IR, MS and X-Ray crystallography. The phosphine oxide derivative was reacted with a selection of lanthanide( iii ) nitrates and triflates, LnX 3 , to give the resultant metal–ligand complexes. These complexes have also been characterized by NMR, IR, MS and X-Ray crystallography. Single crystal X-Ray diffraction data shows a difference in metal–ligand complex stoichiometry and stereochemistry depending on the counteranion (nitrate vs. triflate). The [Ln(Ar 3 PO) 3 (NO 3 ) 3 ] ligand–nitrate complexes are nine-coordinate to the metal in the solid state (bidentate nitrate), featuring a 1 : 3 lanthanide–ligand ratio and bear an overall octahedral arrangement of the six, coordinated ligands. Our [Ln(Ar 3 PO) 3 (NO 3 ) 3 ] ligand–nitrate complexes gave three examples of fac -stereochemistry, where mer -stereochemistry is almost universally observed in the literature of highly related [Ln(Ar 3 PO) 3 (NO 3 ) 3 ] complexes. For the Tb complexes, two different arrangements of the ligands around the metal were observed in the solid state for [Tb(Ar 3 PO) 3 (NO 3 ) 3 ] and [Tb(Ar 3 PO) 4 (OTf) 2 ] [OTf]. [Tb(Ar 3 PO) 3 (NO 3 ) 3 ] is strictly nine-coordinate, ligand mer -stereochemistry in the solid state, and [Tb(Ar 3 PO) 4 (OTf) 2 ] [OTf] is strictly octahedral, six-coordinate, with a square-planar stereochemical arrangement of the phosphine oxide ligands around the metal. 

The synthesis of the title compound, C 13 H 21 NO 2 S, is reported here along with its crystal structure. This compound crystallizes with two molecules in the asymmetric unit. The sulfonamide functional group of this structure features S=O bond lengths ranging from 1.433 (3) to 1.439 (3) Å, S—C bond lengths of 1.777 (3) and 1.773 (4) Å, and S—N bond lengths of 1.622 (3) and 1.624 (3) Å. When viewing the molecules down the S—N bond, the isopropyl groups are gauche to the aromatic ring. On each molecule, two methyl hydrogen atoms of one isopropyl group are engaged in intramolecular C—H...O hydrogen bonds with a nearby sulfonamide oxygen atom. Intermolecular C—H...O hydrogen bonds and C—H...π interactions link molecules of the title compound in the solid state. 

Treatment of 2,4-dinitrophenol with sulfonyl chlorides in the presence of pyridine results in the formation of undesired pyridinium salts. In non-aqueous environments, the formation of the insoluble pyridinium salt greatly affects the formation of the desired product. A facile method of producing the desired sulfonate involves the use of an aqueous base with a water-miscible solvent. Herein, we present the optimization of methods for the formation of sulfonates and its application in the production of desired x-substituted 2,4-dinitrophenyl-4′-phenylbenzenesulfonates. This strategy is environmentally benign and supports a wide range of starting materials. Additionally, the intermolecular interactions of these sulfonate compounds were investigated using single-crystal x-ray diffraction data. 

This paper describes the synthesis of two beta-phosphorylamide ligands and their coordination chemistry with the Ln ions Tb3+, Eu3+, and Sm3+. Both the ligands and Ln complexes were characterized by IR, NMR, MS, and X-ray crystallography. The luminescence properties of the Tb3+ and Eu3+ complexes were also characterized, including the acquisition of lifetime decay curves. In the solid state, the Tb3+ and Sm3+ ligand complexes were found to have a 2:2 stoichiometry when analyzed by X-ray diffraction. In these structures, the Ln ion was bound by both oxygen atoms of each beta-phosphorylamide moiety of the ligands. The Tb3+ and Eu3+ complexes were modestly emissive as solutions in acetonitrile, with lifetime values that fell within typical ranges. 

The molecular structure of the title compound, C 11 H 15 NO 2 S, features a sulfonamide group with S=O bond lengths of 1.4357 (16) and 1.4349 (16) Å, an S—N bond length of 1.625 (2) Å, and an S—C bond length of 1.770 (2) Å. When viewing the molecule down the S—N bond, both N—C bonds of the pyrrolidine ring are oriented gauche to the S—C bond with torsion angles of −65.6 (2)° and 76.2 (2)°. The crystal structure features both intra- and intermolecular C—H...O hydrogen bonds, as well as intermolecular C—H...π and π–π interactions, leading to the formation of sheets parallel to the ac plane. 

The crystal structure of the title sulfonamide, C 10 H 15 NO 2 S, comprises two molecules in the asymmetric unit. The S=O bond lengths of the sulfonamide functional group range from 1.428 (2) to 1.441 (2) Å, with S—C bond lengths of 1.766 (3) Å (for both molecules in the asymmetric unit), and S—N bond lengths of 1.618 (2) and 1.622 (3) Å, respectively. When both molecules are viewed down the N—S bond, the propyl group is gauche to the toluene moiety. In the crystal structure, molecules of the title compound are arranged in an intricate three-dimensional network that is formed via intermolecular C—H...O and N—H...O hydrogen bonds. The crystal structure was refined from a crystal twinned by inversion. 

The title compound, C 15 H 17 NO 2 S, was synthesized via a substitution reaction between 4-methylbenzylamine and p -toluenesulfonyl chloride. In the crystal, N—H...O hydrogen bonds link the molecules, forming ribbons running along the b -axis direction. One of the aromatic rings hosts two intermolecular C—H...π interactions that link these hydrogen-bonded ribbons into a three-dimensional network. 

The syntheses and crystal structures of the two title compounds, C 11 H 10 O 3 ( I ) and C 17 H 14 BrNO 2 ( II ), both containing the bicyclo[2.2.2]octene ring system, are reported here [the structure of I has been reported previously: White & Goh (2014). Private Communication (refcode HOKRIK). CCDC, Cambridge, England]. The bond lengths and angles of the bicyclo[2.2.2]octene ring system are similar for both structures. The imide functional group of II features carbonyl C=O bond lengths of 1.209 (2) and 1.210 (2) Å, with C—N bond lengths of 1.393 (2) and 1.397 (2) Å. The five-membered imide ring is nearly planar, and it is positioned exo relative to the alkene bridgehead carbon atoms of the bicyclo[2.2.2]octene ring system. Non-covalent interactions present in the crystal structure of II include a number of C—H...O interactions. The extended structure of II also features C—H...O hydrogen bonds as well as C—H...π and lone pair–π interactions, which combine together to create supramolecular sheets.