Investigation of the substituted-titanium nanocages using computational chemistry

We are investigated substitution effects of titanium heteroatoms on band gap, charge and local reactivity of C_20-nTi_n heterofullerenes (n = 1-5), at different levels and basis sets. The C₁₈Ti_2-2 nanocage is considered as the most kinetically stable species with the widest band gap of 2.86 eV, in which two carbon atoms are substituted by two Ti atoms in equatorial position, individually. The charges on carbon atoms of C₂₀ are roughly zero, while high positive charge (1.256) on the surface of C₁₉Ti₁ prompts this heteofullerene for hydrogen storage. The positive atomic charge on Ti atoms and negative atomic charge on their adjacent C atoms implies that these sites can be influenced more readily by nucleophilic and electrophilic regents, respectively. We examined the usefulness of local reactivity descriptors to predict the reactivity of Ti-C atomic sites on the external surface of the heterofullerenes. The properties determined include Fukui function (F.F.); f (k) and local softness s (k) on the surfaces of the investigated hollow cages. Geometry optimization results reveal that titanium atoms can be comfortably incorporated into the CC network of fullerene. It is most likely associated with the triple-coordination characteristic of titanium atoms, which can well match with the sp²-hybridized carbon bonding structure. According to the values of f (k) and s (k) for the C₁₅Ti₅ heterofullerene; the carbon atoms in the cap regions exhibit a different reactivity pattern than those in the equatorial portion of the heterofullerene. The titanium impurity can significantly improve the fullerene's surface reactivity and it allows controlling their surface properties. The band gap of C_20-nTi_n …..(H₂)_n structures is decreased with increasing n. Hence, C₁₅Ti₅ is found as the best hydrogen adsorbent.

Revisiting the Mukaiyama-type epoxidation for the conversion of styrene into styrene carbonate in the presence of O2 and CO2

Alkene epoxidation using the Mukaiyama process involving O2 and a sacrificial aldehyde, as the first step of the global alkene oxidative carboxylation, does not necessarily require a metal catalyst.

Chiral Graphene Hybrid Materials: Structures, Properties, and Chiral Applications

Chirality has become an important research subject. The research areas associated with chirality are under substantial development. Meanwhile, graphene is a rapidly growing star material and has hard-wired into diverse disciplines. Rational combination of graphene and chirality undoubtedly creates unprecedented functional materials and may also lead to great findings. This hypothesis has been clearly justified by the sizable number of studies. Unfortunately, there has not been any previous review paper summarizing the scattered studies and advancements on this topic so far. This overview paper attempts to review the progress made in chiral materials developed from graphene and their derivatives, with the hope of providing a systemic knowledge about the construction of chiral graphenes and chiral applications thereof. Recently emerging directions, existing challenges, and future perspectives are also presented. It is hoped this paper will arouse more interest and promote further faster progress in these significant research areas.

Catalytic epoxidation of olefins in liquid phase over manganese based magnetic nanoparticles

Epoxidation of olefins stands out as a crucial class of reactions and is of great interest in academic research and industry due to the production of various important fine chemicals and intermediates. Manganese complexes have the potential to catalyze the epoxidation of olefins with high efficiency. Magnetic nanocatalysts have attracted significant attention for immobilizing homogeneous transition metal complexes. Easy separation by external magnetic fields, nontoxicity, and a core shell structure are the main advantages of magnetic nanocatalysts over other heterogeneous catalysts. The method of functionalizing magnetic nanoparticles and of anchoring homogeneous metal complexes has significant effects on catalytic performance. Therefore, a critical review of recent research progress on manganese complexes' immobilization on magnetic nanoparticles for liquid phase olefin epoxidation is necessary. In this work, magnetic nanoparticles are categorized according to their preparation procedures and structures. The physical/chemical properties, catalytic performance for olefin epoxidation, reusability and plausible reaction mechanisms will be discussed, in an attempt to unravel the structure-function relationship and to guide the future study of MNPs' design for olefin epoxidations.