Related Experiment Video
Updated: Jan 17, 2026
Construction and Systematical Symmetric Studies of a Series of Supramolecular Clusters with Binary or Ternary Ammonium Triphenylacetates
Published on: February 15, 2016
Siamese Twin Homocarbaporphyrin Dimer: Nonplanar Architecture, Localized Conjugation and Bis-BIII Complex
Rampal Vishwakarma1, Prakhar Gupta2, Ashutosh Behera1
1School of Chemical Sciences, National Institute of Science Education and Research (NISER), An OCC of Homi Bhabha National Institute, Bhubaneswar, Odisha, 752050, India.
Abstract:
Architecturally complex π-systems that defy planarity are increasingly sought for their unconventional electronic behaviour and functional adaptability. Among macrocyclic scaffolds, those capable of sustaining nonplanar yet stable conformations prompt to explore novel regimes of conjugation and stimuli-responsive behaviour. In this study, we present a structurally rigid, double-looped homocarbaporphyrin dimer that adopts a figure-eight conformation, generated by fusing two ortho-benzannulated monomeric units through their C2-bridges. This macrocycle features a Siamese twin molecular architecture wherein the flanking p-phenylene moieties introduce a twist that precludes macrocyclic π-delocalization, rendering the system globally nonaromatic. Notably, the overall geometry of homocarbaporphyrin dimer remains intact upon protonation and BIII coordination, demonstrating exceptional shape persistence under external perturbations. These findings are strongly supported by both spectroscopic and theoretical studies and are unequivocally validated by single-crystal X-ray diffraction analyses. This work advances the design of shape - persistent, nonaromatic macrocyclic systems, offering a blueprint for constructing unconventional π-architectures with tailored electronic properties.
More Related Videos
07:20Amide Coupling Reaction for the Synthesis of Bispyridine-based Ligands and Their Complexation to Platinum as Dinuclear Anticancer Agents
Published on: May 28, 2014
05:32Author Spotlight: Characterizing DNA G-Quadruplex by Bis-3-Chloropiperidine Based Chemical Mapping
Published on: May 12, 2023
Related Concept Videos
02:52Stereoisomerism
Isomers are different chemical species that have the same chemical formula.
Transition metal complexes often exist as geometric isomers, in which the same atoms are connected through the same types of bonds but with differences in their orientation in space. Coordination complexes with two different ligands in the cis and trans positions from a ligand of interest form isomers. For example, the octahedral [Co(NH3)4Cl2]+ ion has two isomers (Figure 1) In the cis...
02:34Structural Isomerism
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can...
02:42Valence Bond Theory
02:46Crystal Field Theory - Tetrahedral and Square Planar 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,...
03:35Hybridization of Atomic Orbitals II
03:02Colors and Magnetism
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...