Crystal structure of 9,9-diethyl-9H-fluorene-2,4,7-tricarbaldehyde

The title compound, C20H18O3, crystallizes in the space group P21/c with one molecule in the asymmetric unit of the cell. The fluorene skeleton is nearly planar and the crystal structure is composed of molecular layers extending parallel to the (302) plane. Within a layer, one formyl oxygen atom participates in the formation of a Carene—H...O bond, which is responsible for the formation of an inversion symmetric supramolecular motif of graph set R 2 2(10). A second oxygen atom is involved in an intramolecular Carene—H...O hydrogen bond and is further connected with a formyl hydrogen atom of an adjacent molecule. A Hirshfeld surface analysis indicated that the most important contributions to the overall surface are from H...H (46.9%), O...H (27.9%) and C...H (17.8%) interactions.

1,4-Dibromo-2,5-bis(phenylalkoxy)benzene Derivatives: C–Br...π(arene) Versus C–H...Br and Br...Br Interactions in the Solid State

We have prepared and characterized 1,4-dibromo-2,5-bis(2-phenylethoxy)benzene (1) and 1,4-dibromo-2,5-bis(3-phenylpropoxy)benzene (2). Their single-crystal structures confirm that, at the molecular level, they are similar with the phenylalkoxy chains in extended conformations. However, there are significant differences in packing interactions. The packing in 1 is dominated by C–Br...π(arene) interactions, with each Br located over one C–C bond of the central arene ring of an adjacent molecule. In contrast, the packing of molecules of 2 involves a combination of C–H...Br hydrogen bonds, Br...Br interactions, and arene–arene π-stacking. The single-crystal structures of both orthorhombic and triclinic polymorphs of 1 have been determined and the packing interactions are shown to be essentially identical.

C—H...O contacts in the crystal structure of 1,3-dithiane 1,1,3,3-tetraoxide

The crystal structure of 1,3-dithiane 1,1,3,3-tetraoxide, C4H8O4S2, has been determined to examine the intermolecular C—H...O hydrogen bonds in a small molecule with highly polarized hydrogen atoms. The crystals are monoclinic, space group Pn, with a = 4.9472 (5), b = 9.9021 (10), c = 7.1002 (7) Å and β = 91.464 (3)° with Z = 2. The molecules form two stacks parallel to the a axis with the molecules being one a translation distance from each other. This stacking involves axial hydrogen atoms on one molecule and the axial oxygen atoms on the adjacent molecule in the stack. None of these C—H...O contacts is particularly short (all are > 2.4 Å). The many C—H...O contacts between the two stacks involve at least one equatorial hydrogen or oxygen atom. Again, no unusually short contacts are found. The whole crystal structure basically consists of a complex network of C—H...O contacts with no single, linear C—H...O contacts, only contacts that involve two (bifurcated), and mostly three or four neighbors.

Tetrel Bonding and Other Non-Covalent Interactions Assisted Supramolecular Aggregation in a New Pb(II) Complex of an Isonicotinohydrazide

A new supramolecular Pb(II) complex [PbL(NO2)]n was synthesized from Pb(NO3)2, N’-(1-(pyridin-2-yl)ethylidene)isonicotinohydrazide (HL) and NaNO2. [PbL(NO2)]n is constructed from discrete [PbL(NO2)] units with an almost ideal N2O3 square pyramidal coordination environment around Pb(II). The ligand L− is coordinated through the 2-pyridyl N-atom, one aza N-atom, and the carbonyl O-atom. The nitrite ligand binds in a κ2-O,O coordination mode through both O-atoms. The Pb(II) center exhibits a hemidirected coordination geometry with a pronounced coordination gap, which allows a close approach of two additional N-atoms arising from the N=C(O) N-atom of an adjacent molecule and from the 4-pyridyl N-atom from the another adjacent molecule, yielding a N4O3 coordination, constructed from two Pb–N and three Pb–O covalent bonds, and two Pb⋯N tetrel bonds. Dimeric units in the structure of [PbL(NO2)]n are formed by the Pb⋯N=C(O) tetrel bonds and intermolecular electrostatically enforced π+⋯π− stacking interactions between the 2- and 4-pyridyl rings and further stabilized by C–H⋯π intermolecular interactions, formed by one of the methyl H-atoms and the 4-pyridyl ring. These dimers are embedded in a 2D network representing a simplified uninodal 3-connected fes (Shubnikov plane net) topology defined by the point symbol (4∙82). The Hirshfeld surface analysis of [PbL(NO2)] revealed that the intermolecular H⋯X (X = H, C, N, O) contacts occupy an overwhelming majority of the molecular surface of the [PbL(NO2)] coordination unit. Furthermore, the structure is characterized by intermolecular C⋯C and C⋯N interactions, corresponding to the intermolecular π⋯π stacking interactions. Notably, intermolecular Pb⋯N and, most interestingly, Pb⋯H interactions are remarkable contributors to the molecular surface of [PbL(NO2)]. While the former contacts are due to the Pb⋯N tetrel bonds, the latter contacts are mainly due to the interaction with the methyl H-atoms in the π⋯π stacked [PbL(NO2)] molecules. Molecular electrostatic potential (MEP) surface calculations showed marked electrostatic contributions to both the Pb⋯N tetrel bonds and the dimer forming π+⋯π− stacking interactions. Quantum theory of atoms in molecules (QTAIM) analyses underlined the tetrel bonding character of the Pb⋯N interactions. The manifold non-covalent interactions found in this supramolecular assembly are the result of the proper combination of the polyfunctional multidentate pyridine-hydrazide ligand and the small nitrito auxiliary ligand.

6-[(tert-Butyldimethylsilyl)oxy]-3-ethenyl-7-methoxy-4-[(trimethylsilyl)ethynyl]naphtho[2,3-c]furan-1(3H)-one

The tricyclic core in the title compound, C26H34O4Si2, shows disorder of the furan ring and deviates slightly from planarity, with the largest displacement from the least-squares plane [0.166 (2) Å] for the major disordered part of the methine C atom. To this C atom the likewise disordered vinyl group is attached, lying nearly perpendicular to the tricyclic core. In the crystal, mutual C—H...π interactions between the methine group of the furan ring and the central ring of the tricyclic core of an adjacent molecule lead to inversion-related dimers.

Crystal structure of 4-[(1R,2S,5R)-2-isopropyl-5-methylcyclohexyl] 2-methyl (2S,4S,5R)-1-[(2S,3R,5R)-5-methoxycarbonyl-2-(2-methylphenyl)pyrrolidine-3-carbonyl]-5-(2-methylphenyl)pyrrolidine-2,4-dicarboxylate

The title compound, C38H50N2O7, represents a chiral β-proline dipeptide. Corresponding stereogenic centres of constituting pyrrolidine units have opposite absolute configurations. The central amide fragment is planar within 0.1 Å and adopts a Z configuration along the N—CO bond. In the crystal, the hydrogen atoms of the methylene groups form several short intermolecular C—H...O contacts with the carbonyl oxygen atoms of an adjacent molecule. The only active amino hydrogen atom is not involved in hydrogen bonding.

Crystal structure of (2-acetylferrocen-1-yl)boronic acid

(2-Acetylferrocen-1-yl)boronic acid, [Fe(C5H5)(C7H8BO3)] or 2-C(O)CH3-1-B(OH)2–Fc [Fc = Fe(η5-C5H3)(η5-C5H5)], crystallizes in the centrosymmetric space group P21/n. The boronic acid functionality interacts via intramolecular hydrogen bonds with the acetyl group and with the –B(OH)2 functionality of an adjacent molecule. The resulting centrosymmetric dimer exhibits an anti-positioning of the ferrocenyl moieties towards the central B2O4 plane. Consequently, an (Rp ,Sp )-, i.e. a meso configuration is present for this dimer. In the crystal, weak C—H...O hydrogen bonds consolidate the molecular packing.

Crystal structures of two 1,3-thiazolidin-4-one derivatives featuring sulfide and sulfone functional groups

The crystal structures of two closely related compounds, 1-cyclohexyl-2-(2-nitrophenyl)-1,3-thiazolidin-4-one, C15H18N2O3S, (1) and 1-cyclohexyl-2-(2-nitrophenyl)-1,3-thiazolidin-4-one 1,1-dioxide, C15H18N2O5S, (2), are presented. These compounds are comprised of three types of rings: thiazolidinone, nitrophenyl and cyclohexyl. In both structures, the rings are close to mutually perpendicular, with interplanar dihedral angles greater than 80° in each case. The thiazolidinone rings in both structures exhibit envelope puckering with the S atom as flap and the cyclohexyl rings are in their expected chair conformations. The two structures superpose fairly well, except for the orientation of the nitro groups with respect to their host phenyl ring, with a difference of about 10° between 1 and 2. The extended structure of 1 has two kinds of weak C—H...O interactions, giving rise to a closed ring formation involving three symmetry-related molecules. Structure 2 has four C—H...O interactions, two of which are exclusively between symmetry-related thiazolidinone dioxide moieties and have a parallel `give-and-take-fashion' counterpart. In the other two interactions, the nitrophenyl ring and the cyclohexane ring each offer an H atom to the two O atoms on the sulfone group. Additionally, a C—H...π interaction between a C—H group of the cyclohexane ring and the nitrophenyl ring of an adjacent molecule helps to consolidate the structure.

Crystal structure of (−)-(S)-4-[(2S,3S,4S,Z)-3-hydroxy-4-methylhept-5-en-2-yl]-1,3-dioxolan-2-one

The title compound, C11H18O4, consists of ananti,anti,anti-stereotetrad with a 1,2-carbonate and an alkene motif. The molecule displays a common zigzag conformation. The five-membered ring has a twisted conformation on the C—C bond. In the crystal, a strong intermolecular hydrogen bond between the hydroxy group and the carboxylate moiety from an adjacent molecule forms chains propagating along theb-axis direction. The absolute structure of the molecule in the crystal was determined by resonant scattering [Flack parameter = 0.05 (6)].

Crystal structure of tetraaquabis(pyrimidin-1-ium-4,6-diolato-κO4)manganese(II)

The MnIIion in the structure of the mononuclear title compound, [Mn(C4H3N2O2)2(H2O)4], is situated on an inversion center and is coordinated by two O atoms from two deprotonated 4,6-dihydroxypyrimidine ligands and by four O atoms from water molecules giving rise to a slightly distorted octahedral coordination sphere. The complex includes an intramolecular hydrogen bond between an aqua ligand and the non-protonated N ring atom. The extended structure is stabilized by intermolecular hydrogen bonds between aqua ligands, by hydrogen bonds between N and O atoms of the ligands of adjacent molecules, and by hydrogen bonds between aqua ligands and the non-coordinating O atom of an adjacent molecule.