Related Experiment Video
Updated: Jun 5, 2026
14:11
Synthesis of pH Dependent Pyrazole, Imidazole, and Isoindolone Dipyrrinone Fluorophores using a Claisen-Schmidt Condensation Approach
Published on: June 10, 2021
A triclinic modification of 5,5'-dinitro-2,2'-dithio-dipyridine
Acta Crystallographica. Section E, Structure Reports Online
|January 5, 2011
Summary
This study reveals a new triclinic crystal structure for C(10)H(6)N(4)O(4)S(2), differing from a previously reported monoclinic form. Key differences include distinct C-S-S-C torsion angles and intramolecular interactions.
Area of Science:
- Crystallography
- Solid-state chemistry
- Materials science
Background:
- Polymorphism, the ability of a solid material to exist in more than one crystal form, is crucial in materials science.
- Previous research reported a monoclinic crystal structure for C(10)H(6)N(4)O(4)S(2).
- Understanding structural variations in crystalline compounds is essential for predicting and controlling their properties.
Purpose of the Study:
- To characterize a newly identified triclinic polymorph of C(10)H(6)N(4)O(4)S(2).
- To compare the structural features of the triclinic polymorph with the previously reported monoclinic form.
- To investigate the influence of crystal packing on molecular conformation and intermolecular interactions.
Main Methods:
- Single-crystal X-ray diffraction was employed to determine the crystal structure of the triclinic polymorph.
- The crystal structure was analyzed to identify key geometric parameters, including bond lengths, bond angles, and torsion angles.
- Comparisons were made with the published crystallographic data of the monoclinic polymorph.
Main Results:
- The asymmetric unit of the triclinic polymorph contains two independent, similar molecules.
- A significant difference was observed in the C-S-S-C torsion angle between the two polymorphs (-80.13° and -79.8° for the triclinic form vs. 0° for the monoclinic form).
- The triclinic polymorph exhibits two intramolecular C-H⋯S interactions, which are not present in the monoclinic form.
Conclusions:
- The study successfully identified and characterized a new triclinic polymorph of C(10)H(6)N(4)O(4)S(2).
- The observed structural differences, particularly the C-S-S-C torsion angle and the presence of intramolecular C-H⋯S interactions, highlight the conformational flexibility and packing variations possible for this compound.
- These findings contribute to the understanding of polymorphism and its impact on molecular structure and interactions in crystalline organic compounds.
Related Concept Videos
02:46Crystal Field Theory - Tetrahedral and Square Planar Complexes
Tetrahedral Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
01:18Aromatic Hydrocarbon Cations: Structural Overview
Cycloheptatriene is a neutral monocyclic unsaturated hydrocarbon that consists of an odd number of carbon atoms and an intervening sp3 carbon in the ring. The three double bonds in the ring correspond to 6 π electrons, which is a Huckel number, and therefore satisfies the criteria of 4n + 2 π electrons. However, the intervening sp3 carbon disrupts the continuous overlap of p orbitals. As a result, cycloheptatriene is not aromatic.
Removing one hydrogen from the intervening CH2 group with both...
Removing one hydrogen from the intervening CH2 group with both...
![[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2Ffiles%2Fmedia%2Fscience-education%2Fscience-education-thumbs%2F12417.jpg&w=3840&q=75)
01:16[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction
The Diels–Alder reaction is an example of a thermal pericyclic reaction between a conjugated diene and an alkene or alkyne, commonly referred to as a dienophile. The reaction involves a concerted movement of six π electrons, four from the diene and two from the dienophile, forming an unsaturated six-membered ring. As a result, these reactions are classified as [4+2] cycloadditions.
01:29Diels–Alder Reaction: Characteristics of Dienes
The Diels–Alder reaction brings together a diene and a dienophile to form a six-membered ring. Both components have unique characteristics that influence the rate of the reaction.
Characteristics of the diene
Conformation
The simplest example of a diene is 1,3-butadiene, an acyclic conjugated π system. At room temperature, the molecule exists as a mixture of s-cis and s-trans conformers by virtue of rotation around the carbon–carbon single bond. Although the s-trans isomer is more stable, the...
Characteristics of the diene
Conformation
The simplest example of a diene is 1,3-butadiene, an acyclic conjugated π system. At room temperature, the molecule exists as a mixture of s-cis and s-trans conformers by virtue of rotation around the carbon–carbon single bond. Although the s-trans isomer is more stable, the...
01:25Basicity of Heterocyclic Aromatic Amines
Heterocyclic amines, where the N atom is a part of an alicyclic system, are similar in basicity to alkylamines. Interestingly, the heterocyclic amine having a nitrogen atom as part of an aromatic ring has much less basicity than its corresponding alicyclic counterpart. For this reason, as presented in Figure 1, piperidine (pKb = 2.8) is significantly more basic than pyridine (pKb = 8.8).
01:57Preparation of Diols and Pinacol Rearrangement
Compounds bearing two hydroxyl groups are known as diols. When the hydroxyl groups are located on adjacent carbon atoms, the diols are called vicinal diols or glycols. Under acidic conditions, vicinal diols undergo a specific reaction called pinacol rearrangement.
The reaction begins with transferring a proton from the acid catalyst to one of the hydroxyl groups, producing an oxonium ion.
The reaction begins with transferring a proton from the acid catalyst to one of the hydroxyl groups, producing an oxonium ion.