Ligand substitution in chromium(III)-aqua complexes by l-histidine: kinetic resolution of two long-lived intermediates

On the structural, electronic, and optical properties of L-histidine crystal: a DFT study

CONTEXT

The monoclinic L-histidine crystal is critical for protein structure and function and is also found in the myelin of brain nerve cells. This study numerically examines its structural, electronic, and optical properties. Our findings indicate that the L-histidine crystal has an insulating band gap of approximately 4.38 eV. Additionally, electron and hole effective masses range between 3.92[Formula: see text]-15.33[Formula: see text] and 4.16[Formula: see text]-7.53[Formula: see text], respectively. Furthermore, our investigation suggests that the L-histidine crystal is an excellent UV collector due to its strong optical absorption activity for photon energies exceeding 3.5 eV.

METHODS

To investigate the structural, electronic, and optical properties of L-histidine crystals, we used the Biovia Materials Studio software to conduct Density Functional Theory (DFT) simulations as implemented in the CASTEP code. Our DFT calculations were performed using the generalized gradient approximation (GGA) as parameterized by the Perdew-Burke-Ernzerhof (PBE) exchange-correlation functional, with an additional dispersion energy correction (PBE [Formula: see text] TS) based on the model proposed by Tkatchenko and Scheffler to describe van der Waals interactions. Additionally, we employed the norm-conserving pseudopotential to treat core electrons.

Solvothermal preparation of luminescent zinc(II) and cadmium(II) coordination complexes based on the new bi-functional building block and photo-luminescent sensing for Cu2+, Al3+ and L-lysine

In industry, over usage of Cu²⁺ and Al³⁺ will lead to toxic wastewater, which further to give serious pollution for the environment. On the other hand, L-lysine can enhance serotonin release in the amygdala, with subsequent changes in psychobehavioral responses to stress. Therefore it is the urgent problem to design a method for detecting the amount of Cu²⁺, Al³⁺, and L-lysine. In this work, through the solvothermal synthesis method, two new coordination complexes based on the new bifunctional building block 4'-(1H-1,2,4-triazole-1-yl)- [1,1'-biphenyl]-4-carboxylic acid (HL) have been synthesized, namely, [Zn(L)₂·4H₂O] (complex 1) and [Cd(L)₂·4H₂O] (complex 2). X-ray single-crystal diffractometer was used to analyze its structure, powder X-ray diffraction (PXRD) patterns confirmed that 1 and 2 powder's purity and 1 can keep stable during the detection process of Cu²⁺, Al³⁺, and L-lysine, respectively. Elemental analysis, thermogravimetric analysis, infrared analysis, ultraviolet analysis and fluorescent spectrum have been used to characterize these complexes. The photo-luminescent test showed that 1 can accurately recognize Al³⁺ and Cu²⁺ among various cations. On the other hand, 1 can distinguish L-lysine among amino acid molecules. Therefore, 1 can be utilized as a multifunctional fluorescent probe for Al³⁺(K_sv = 1.5570 × 10⁴ [M]^-1), Cu²⁺(K_sv = 1.4948 × 10⁴ [M]^-1) and L-lysine (K_sv = 4.9118 × 10⁴ [M]^-1) with low detection limits (17.5 μM, 18.2 μM, 5.6 μM) respectively.

Dual-emission CdTe quantum dot@ZIF-365 ratiometric fluorescent sensor and application for highly sensitive detection of l-histidine and Cu2

l-histidine acts as a semi-essential amino acid, which is medically used in the treatment of gastric ulcer, anemia, allergies. However, the overuse of l-histidine will result in terrible damage to heart disease, slow growth of animals and water pollution in the environment. In addition, Cu²⁺ pollution is common environmental pollution in the industry. It has the characteristics of high accumulation, migration, and persistence. Given this, through the post-synthesis strategy, CdTe quantum dots (QDs) were the first time to introduce into zeolitic imidazolate framework-ZIF-365 to synthesis dual-emission hybrid material CdTe@ZIF-365 with high quantum yield. TEM mappings and N₂ absorption tests are applied to confirm the combination mode between CdTe quantum dots and ZIF-365. It should be noted that CdTe@ZIF-365 can be successfully utilized as a bi-functional ratiometric sensor for highly sensitive discrimination of l-histidine and Cu²⁺. Firstly, CdTe@ZIF-365 is applied to a fluorescent ratiometric sensor for Cu²⁺ with high sensitivity (the K_sv value is 2.7417✕10⁷ [M^-1]) and selectivity in the mixed cation ions' solution. On the other hand, CdTe@ZIF-365 also behaved as the first example for an excellent ratiometric fluorescent senor for l-histidine with high sensitivity (the K_sv value is 6.0507✕10⁸ [M^-1]) and selectivity in the mixed amino acids' solutions.

Cascade transformations of (±)-citronellal to menthol over extruded Ru-MCM-41 catalysts in a continuous reactor

Catalytic cascade transformations of (±)-citronellal in a continuous mode over bifunctional ruthenium/MCM-41/binder extrudates with different metal location.