Based on the ligand H₄Salen-8^tBu (salen-4), a new dinuclear cobalt complex (salen-4)[Co(III)TFA]₂ (salen-4 = 3,5-di-tert-butylsalicylaldehyde-3,3′-diaminobiphenylamine; TFA = trifluoroacetic acid) has been firstly synthesized and characterized. It shows high catalytic activity for the copolymerization of propylene oxide (PO) and carbon dioxide (CO₂), yielding regioregular poly(propylene carbonate) (PPC) with little generation of propylene carbonate (PC) by-product. It has been found that (salen-4)[Co(III)TFA]₂ shows higher activity at milder conditions, generating a polymer with maximum Mn of 293 kg/mol and a narrow molecular weight distribution PDI of 1.35. The influences of reaction time, CO₂ pressure, reaction temperature, nature of the cocatalyst, catalyst dosage and substrate concentration on the molecular weight, yield and selectivity of the polymer were explored in detail. The results showed that the (salen-4)[Co(III)TFA]₂/[PPN]TFA catalyst system demonstrated a remarkable TOF as high as 735 h^–1. In addition, a hypothetical catalytic reaction mechanism was proposed based on density functional theory (DFT) calculations and the catalytic reaction results of the (salen-4)[Co(III)TFA]₂.

Though ionic liquids (ILs) are considered potential materials for CO₂ capture because of their unique properties, it is time-consuming and costly to choose task-specific and suitable IL using the traditional “try-and-error” method. From the point of molecular design view, 25 cations and 20 anions are combined and screened using COSMOtherm to predict CO₂ solubility at 298 K and 100 kPa. The prediction result showed that ILs with bFAP(tris(nonafluorobutyl)trifluorophosphate) anion could dissolve more CO₂ than any others. To further understand the absorption performance of CO₂ in ILs, molecular dynamic simulations are carried out to explore the interactions between CO₂ and the four selected ILs, namely, [EMPyr][bFAP](1-ethyl-2-methylpyrazolium tris(nonafluorobutyl)trifluorophosphate), [B(Hex)₃P][bFAP](butyl-trihexyl-phosphonium tris(nonafluorobutyl) trif-luorobutyl trifluorophosphate), [(Me)₅isobuGua][bFAP](n,n,n,n,n-pentamethyl-n-isopropylguanidinium tris(nona-fluorobutyl)-trifluorophosphate), and [BEIM][bFAP] (1-butyl-3-ethyl-imidazolium tris(nonafluorobutyl)trifluo-rophosphate), at the atomic and molecular levels.

Based on the ligand H2dpPzda (1), a novel cobalt complex [Co(H2dpPzda)(NCS)2]·CH3OH(2) has been synthesized and characterized. The Complex 2 exhibited excellent catalytic performance for converting CO2 into cyclic carbonates under mild conditions. For propylene oxide (PO) and CO2 synthesis of propylene carbonate (PC), the catalytic system showed a remarkable TOF as high as 29,200 h−1. The catalytic system also showed broad substrate scope of epoxide. Additionally, the catalyst could be recycled to maintain the integrity of the structure and remained equal to the level of its catalytic activity even after seven catalytic rounds. Additionally, a possible catalytic mechanism was proposed due to the high catalytic activity which might be owing to the synergism of Lewis acidic metal centers and N group.

Graphene-based nanocomposite films (NCFs) are in high demand due to their superior photoelectric and thermal properties, but their stability and mechanical properties form a bottleneck. Herein, a facile approach was used to prepare nacre-mimetic NCFs through the non-covalent self-assembly of graphene oxide (GO) and biocompatible proteins. Various characterization techniques were employed to characterize the as-prepared NCFs and to track the interactions between GO and proteins. The conformational changes of various proteins induced by GO determined the film-forming ability of NCFs, and the binding of bull serum albumin (BSA)/hemoglobin (HB) on GO’s surface was beneficial for improving the stability of as-prepared NCFs. Compared with the GO film without any additive, the indentation hardness and equivalent elastic modulus could be improved by 50.0% and 68.6% for GO–BSA NCF; and 100% and 87.5% for GO–HB NCF. Our strategy should be facile and effective for fabricating well-designed bio-nanocomposites for universal functional applications.

Electronic structural properties of the three different imidazolium-based ionic liquids, namely, 1-butyl-3-methyl imidazolium bromide (C₄mimBr), 1-(4-hydroxybutyl)-3-methylimidazolium bromide (C₄OHmimBr), and 1-(4-aminobutyl)-3-methylimidazolium bromide (C₄NH₂mimBr), were investigated with density functional theory at the B3LYP/6-311++G(d,p) level. The conformations of the mentioned cations were fully studied first using CONFLEX 8.A program. The quantum theory of atoms in molecules was used to investigate the nature of intramolecular interactions. The counterpoise-corrected ion pairs binding energies were obtained at the same level of theory. Natural bond orbital analyses show that the largest intra-molecular interaction comes from the orbital overlap between n(N1) and π* (N4–C5) in the mentioned compounds. The energy levels of frontier molecular orbitals (FMOs) are displayed. The global quantum chemical descriptors are also calculated based on the energy values of FMOs.