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The molecular structure of the tripodal carbamoylmethylphosphine oxide compound diethyl {[(5-[2-(diethoxyphosphoryl)acetamido]-3-{2-[2-(diethoxyphosphoryl)acetamido]ethyl}pentyl)carbamoyl]methyl}phosphonate, C₂₅H₅₂N₃O₁₂P₃, features six intramolecular hydrogen-bonding interactions. The phosphonate groups have key bond lengths ranging from 1.4696 (12) to 1.4729 (12) Å (P=O), 1.5681 (11) to 1.5811 (12) Å (P—O) and 1.7881 (16) to 1.7936 (16) Å (P—C). Each amide group adopts a nearly perfecttransgeometry, and the geometry around each phophorus atom resembles a slightly distorted tetrahedron. 

The title compound, C₈H₁₈NO₂⁺·Br⁻·C₈H₁₇NO₂, crystallizes as the bromide salt of a 50:50 mixture of (triethylazaniumyl)carboxylic acid and the zwitterionic (triethylazaniumyl)carboxylate. The two organic entities are linked by a half-occupied bridging carboxylic acid hydrogen atom that is hydrogen-bonded to the carboxylate group of the second molecule. The tetralkylammonium group adopts a nearly perfect tetrahedral shape around the nitrogen atom with bond lengths that agree with known values. The carboxylic acid/carboxylate group is orientedantito one of the ethyl groups on the ammonium group, and the carbonyl oxygen atom is engaged in intramolecular C—H...O hydrogen bonds. 

Four β-carbonylphosphine oxide compounds were complexed with four Ln(NO₃)₃salts (Ln = Sm, Eu, Tb, Dy). The Ln–ligand complexes were characterized in the solid state (IR, CHN) and as solutions in acetonitrile (NMR, LR-MS, photophysical properties). 

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. 

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.