Full-Dimensional Control of Covalent Organic Frameworks Through Repulsion-Torsion Effect: Prominent 1D Above 2D and
Kaifu Yu1, Pan He1, Dong Zhang2
1College of Chemistry, Sichuan University, Chengdu, 610064, P.R. China.
Abstract:
Exploring the impact of different dimensions on the properties and functions of covalent organic frameworks (COFs) has always been a key goal, as this can provide feedback to assist in the design of advanced COFs. However, this goal has never been performed simultaneously in one-dimensional (1D), two-dimensional (2D), and three-dimensional (3D) COFs, due to the difficulty of dimensional control. Herein, for the first time, we synthesized three novel COFs with different dimensions, from similar composition by manipulating the conformation of the molecular building blocks through repulsion-torsion effect. Impressively, the strong repulsion-torsion effect transformed the planar building block into a non-planar building block, resulting in the construction of 2D and 3D COFs, respectively. Moreover, when we consciously reduced the repulsion-torsion effect, the resulting intramolecular conformation struggled to meet the requirements for the formation of 2D and 3D structures, ultimately generating a rare 1D COF. Further research indicated the charge transfer efficiency and photocatalytic performance of the resulting COFs followed a dimensional order of 1D > 3D > 2D. This phenomenon was attributed to the unique in-plane and out-of-plane double rotational restriction (IODRR) effect in the 1D structure, which stabilized the aromatic framework and thus greatly reduced the carrier recombination probability and energy loss.
Related Concept Videos
02:36Molecular Geometry and Dipole Moments
02:58Crystal Field Theory - Octahedral Complexes
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
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,...
02:40MO Theory and Covalent Bonding
02:06Newman Projections
The organic molecules rotate across the single bonds leading to numerous temporary three-dimensional structures of varying energy known as...
02:11Conformations of Cyclohexane
The chair form is the most stable and derives its name from its resemblance to the “easy chair.” In the chair conformation, two carbon atoms are arranged out-of-plane — one above and one below, minimizing the torsional strain. In the chair form, the bond angle is very close to the ideal...