Narrow Results

A chiral bisporphyrin containing hydroxy groups in the linker H₄(L-TABis) was designed and synthesized. The CD spectra show that the intensity of the CD signal increases approximately 12-fold upon metalation with Zn${}^{2+}$ (up to 1450 cm${}^{-1}$M${}^{-1})$. Our investigation suggests that the Zn-OH coordination interactions lead to enhanced CD in [Zn₂(L-TABis)]. The DFT-optimized structure of [Zn₂(L-TABis)] indicates that the chirality of L-tartaric acid is transferred to the bisporphyrin to form an M configuration with a shorter Zn$\cdots$Zn distance and a negative C15-C5-C5^′-C15^′ torsional angle, which is consistent with the experimental results. This work presents a useful example of enhancing CD by adjusting the interactions between the substituents in the linker and the center metal ions.

Spinel LiMn₂O₄ was synthesized by a modified solid state reaction. We pretreated the reactants using tartaric acid as complexing agent through a grinding process to obtain uniform distribution of metal ions at atomic level. The structures, morphologies and electrochemical properties of the products were studied by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and galvanostatic charge-discharge test. The results show that adding tartaric acid during the chemical pretreatment plays an important role in the formation of regular and uniform particles, which is beneficial to the electrochemical performance of LiMn₂O₄. At the current density of 100 mA g^-1, the discharge capacity is 118 mAh g^-1 after 50 cycles with the capacity retention of 97%.

The chirality (of Greek χείρ, ch[e]ir: hand) is a fundamental symmetry property of three-dimensional objects. Your two hands are not superimposable. They are mirror images of each other. They are therefore chiral (Figure 10.1). The chirality of your right hand can be seen by trying to put it in a glove for your left hand. The same can be seen by trying to put your left hand into a glove for your right hand. The same experience can be done while putting on shoes. Normally you are not comfortable after exchanging the shoe for the left foot with the one for the right foot…

New derivatives of L-(+)-tartaric acid have been synthesized from the monomethyl-2,3-O-isopropylidene (R,R)-(+)-tartrate by visible light photolysis of its N-hydroxy-2-thiopyridone ester derivative in presence of activated alkenes. The carbon radical generated at the dioxolane ring adds stereoselectively to olefins to give the addition products with retention of configuration.