Related Experiment Video
Updated: Oct 12, 2025
07:14
Author Spotlight: Experimental Approaches for the Synthesis of Low-Valent Metal-Organic Frameworks from Multitopic Phosphine Linkers
Published on: May 12, 2023
3.2K
Coordination-Induced Band Gap Reduction in a Metal-Organic Framework
Craig A Peeples1, Ahmet Çetinkaya2, Patrik Tholen3
1University of Alberta, 116 St. and 85 Ave., Edmonton, Alberta, T6G 2R3, Canada.
Chemistry (Weinheim an Der Bergstrasse, Germany)
|November 22, 2021
Summary
We synthesized TUB1, a novel phosphonate metal-organic framework (MOF) with a high surface area. Its unique structure and electronic properties, influenced by copper atoms, suggest potential applications in materials science.
Area of Science:
- Materials Science
- Inorganic Chemistry
- Crystallography
Background:
- Metal-organic frameworks (MOFs) offer tunable porosity and surface area.
- Phosphonate-based MOFs are explored for diverse applications.
- Understanding structure-property relationships in MOFs is crucial.
Purpose of the Study:
- To synthesize and characterize a novel 3D phosphonate MOF.
- To investigate the electronic properties and band gap of the MOF.
- To elucidate the role of inorganic building units in MOF properties.
Main Methods:
- Solvothermal synthesis of the MOF.
- Gas sorption analysis (BET surface area calculation).
- UV-Vis spectroscopy (Tauc plot for band gap determination).
- Density Functional Theory (DFT) calculations for electronic structure.
Main Results:
- Successful synthesis of a microporous MOF, TUB1 (Cu3(H5-MTPPA)2·2NMP).
- Achieved BET surface area of 766.2 m²/g.
- Determined indirect and direct band gaps of 2.4 eV and 2.7 eV.
- DFT revealed spin-dependent band gaps (0.48 eV and 2.60 eV) influenced by copper coordination.
Conclusions:
- TUB1 exhibits a unique 1D inorganic building unit with varied copper coordination.
- The MOF's band gap is significantly reduced by the presence of square planar copper atoms.
- The findings provide insights into MOF design for tailored electronic properties.
Related Concept Videos
02:42Valence Bond Theory
9.8K
Coordination compounds and complexes exhibit different colors, geometries, and magnetic behavior, depending on the metal atom/ion and ligands from which they are composed. In an attempt to explain the bonding and structure of coordination complexes, Linus Pauling proposed the valence bond theory, or VBT, using the concepts of hybridization and the overlapping of the atomic orbitals. According to VBT, the central metal atom or ion (Lewis acid) hybridizes to provide empty orbitals of suitable...
9.8K
02:58Crystal Field Theory - Octahedral Complexes
28.3K
Crystal Field Theory
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...
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...
28.3K
02:51Metal-Ligand Bonds
22.0K
The hemoglobin in the blood, the chlorophyll in green plants, vitamin B-12, and the catalyst used in the manufacture of polyethylene all contain coordination compounds. Ions of the metals, especially the transition metals, are likely to form complexes.
In these complexes, transition metals form coordinate covalent bonds, a kind of Lewis acid-base interaction in which both of the electrons in the bond are contributed by a donor (Lewis base) to an electron acceptor (Lewis acid). The Lewis acid in...
In these complexes, transition metals form coordinate covalent bonds, a kind of Lewis acid-base interaction in which both of the electrons in the bond are contributed by a donor (Lewis base) to an electron acceptor (Lewis acid). The Lewis acid in...
22.0K
03:02Colors and Magnetism
12.5K
Color in Coordination Complexes
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...
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...
12.5K
02:57Coordination Number and Geometry
17.0K
For transition metal complexes, the coordination number determines the geometry around the central metal ion. Table 1 compares coordination numbers to molecular geometry. The most common structures of the complexes in coordination compounds are octahedral, tetrahedral, and square planar.
17.0K
02:46Crystal Field Theory - Tetrahedral and Square Planar Complexes
45.2K
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,...
45.2K