Dihedral angle

About: Dihedral angle is a research topic. Over the lifetime, 15718 publications have been published within this topic receiving 174904 citations.

Preparation of Cocrystals of 2-Amino-3-nitropyridine with Benzenesulfonic Acids for Second-Order Nonlinear Optical Materials

Abstract: Noncentrosymmetic and chiral cocrystals were prepared from 2-amino-3-nitropyridine (2A3NP) and achiral benzenesulfonic acids (Ar-SO3H), which were designed for second-order nonlinear optical materials. Both components are commonly crystallized in 1:1 ionic forms of 2A3NPH+·Ar-SO3-. The molecular packings of cocrystals are controlled by the aromatic−aromatic interactions as well as multidirectional ionic and hydrogen bonds between the 2A3NPH+ cations and the sulfonate anions. The crystal of 2A3NP with p-toluenesulfonic acid belongs to acentric space group Pna21, in which 2A3NPH+ cations and anions are alternately stacked with some dihedral angle due to the large sulfonate anions to form two independent column structures in a perpendicular direction to each other. The crystal of 2A3NP with p-nitrobenzenesulfonic acid crystallizes into chiral space group P212121. The 2A3NPH+ cations and the anions are also alternately stacked to give herringbone network of 2A3NPH+ cations. The crystal of 2A3NP with 2,5-dimet...

Intermolecular interactions in crystalline 1-(adamantane-1-carbonyl)-3-substituted thioureas with Hirshfeld surface analysis

Abstract: The conformationally congested species 1-(adamantane-1-carbonyl)-3-(2,4,6-trimethylphenyl)thiourea has been prepared and fully characterized by elemental analyses, FTIR, 1H NMR, 13C NMR and mass spectrometry. Its crystal structure was determined by single-crystal X-ray diffraction. The dihedral angle between the plane of the 2,4,6-trimethylphenyl group and the plane of the thiourea fragment was optimized by theoretical calculations applying the B3LYP/6-311++G(d,p) level for the purpose of investigating the conformational effects on the stabilization of the crystal packing. A detailed analysis of the intermolecular interactions in a series of six closely related phenylthiourea species bearing the 1-(adamantane-1-carbonyl) group has been performed based on the Hirshfeld surfaces and their associated two-dimensional fingerprint plots. The relative contributions of the main intermolecular contacts as well as the enrichment ratios derived from the Hirshfeld surface analysis establish the 1-acyl thiourea synthon to be a widespread contributor.

A stable doubly hydrogen-bridged butterfly-shaped diborane(4) compound.

Abstract: In contrast to the common multiple bonding between carbon atoms, multiply bonded boron compounds have still been a synthetic challenge due to the electron deficiency of boron. We now report that a stable doubly hydrogen-bridged diborane(4), EindB(μ-H)2BEind, is produced by the two-electron oxidation of a hydrogen-substituted diborane(4) dianion [Li+(thf)]2[Eind(H)BB(H)Eind]2−, where Eind denotes the 1,1,3,3,5,5,7,7-octaethyl-s-hydrindacen-4-yl. The X-ray crystallography reveals a short B−B distance of 1.4879(7) A in comparison with the normal B−B single bond length (1.72 A), the presence of two hydrogen atoms bridged perpendicular to the B−B bond with a butterfly shape having a dihedral angle of the two BHB triangles of 113(1)°, and a linear geometry around the B−B bond with a C−B−B bond angle of 178.92(4)°. These structural data, experimental electron density analysis, and computational studies confirm the 3-fold bonding (a σ and two π-like bonds) between the two boron atoms incorporating the two bridgin...