In‐Depth Understanding of the Chemical Properties of Rarely Explored Carbide Cluster Metallofullerenes: A Case Study of Sc2C2@C3v(8)‐C82 that Reveals a General Rule

The chemical properties of carbide‐cluster metallofullerenes (CCMFs) remain largely unexplored, although several new members of CCMFs have been discovered recently. Herein, we report the reaction between Sc₂C₂@C_3v(8)‐C₈₂, which is viewed as a prototypical CCMF because of its high abundance, and 3‐triphenylmethyl‐5‐oxazolidinone ( 1 ) to afford the corresponding pyrrolidino derivative Sc₂C₂@C_3v(8)‐C₈₂(CH₂)₂NTrt ( 2 ; Trt=triphenylmethyl). Single‐crystal X‐ray crystallography studies of 2 revealed that the reaction takes place at a [6,6]‐bond junction, which is directly over the encapsulated C₂ unit and is far from either of the two scandium atoms. On the basis of theoretical calculations and by considering previously reports, we have found that a hexagonal carbon ring on the cage of Sc₂C₂@C_3v(8)‐C₈₂ is highly reactive toward different reagents due to the overlap of high p‐orbital axis vector (POAV) angles and large LUMO coefficients. We propose that this highly concentrated area of reactivity is generated by the encapsulation of the Sc₂C₂ cluster because this region is absent from the empty fullerene C_3v(8)‐C₈₂. Moreover, the absorption and electrochemical results confirm that derivative 2 is more stable than pristine Sc₂C₂@C_3v(8)‐C₈₂, thus illuminating its potential applications.     

Imination of sulfoxides mediated by IBX with Sc(OTf)3 as catalyst

Herein we utilized, for the first time, 2-iodoxybenzoate along with scandium triflate as a specific oxidant for PhthNH₂ to create sulfoximines. This method efficiently effects imination of aryl, benzyl, cyclic and alkyl substituted S?O bonds with good to excellent yields. In addition, sterically encumbered sulfoxides have been studied and found that the present protocol is the worthy choice. This facile method does not require either inert atmosphere or anhydrous solvents.     

The β‐Agostic Structure in (C5Me5)2Sc(CH2CH3): Solid‐State NMR Studies of (C5Me5)2Sc−R (R=Me,Ph, Et)

Multinuclear solid‐state NMR studies of Cp*₂Sc?R (Cp*=pentamethylcyclopentadienyl; R=Me, Ph, Et) and DFT calculations show that the Sc?Et complex contains a β‐CH agostic interaction. The static central transition ⁴⁵Sc NMR spectra show that the quadrupolar coupling constants (C_q) follow the trend of Ph≈Me>Et, indicating that the Sc?R bond is different in Cp*₂Sc?Et compared to the methyl and phenyl complexes. Analysis of the chemical shift tensor (CST) shows that the deshielding experienced by Cβ in Sc?CH₂CH₃ is related to coupling between the filled σ_C‐C orbital and the vacant orbital.     

Enantioselective Construction of Silicon‐Stereogenic Silanes by Scandium‐Catalyzed Intermolecular Alkene Hydrosilylation

The catalytic asymmetric construction of silicon‐stereogenic silanes is of great interest and significance, but has met with only limited success to date. We herein report the enantioselective hydrosilylation of alkenes with dihydrosilanes by a chiral half‐sandwich scandium catalyst, which constitutes an efficient and general route for the synthesis of a wide range of enantioenriched silicon‐stereogenic silanes from easily accessible starting materials. This reaction features a broad substrate scope, high yields, and high enantioselectivity. Some of the chiral tertiary silane products were also converted into valuable derivatives, such as chiral silanol, quaternary silane, and benzosilole compounds.     

The influence of mesoporous silica modified with phosphorus and nitrogen‐containing hyperbranched molecules on thermal stability,combustion behavior,and toxic volatiles of epoxy resin

A hybrid material (HPPA‐SH‐mSiO₂) containing multiple flame‐retardant elements was synthesized and characterized using NMR, FTIR, and XPS techniques. This hybrid was synthesized by the “thiol–ene” click reaction of thiol‐functionalized mesoporous silica (SH‐mSiO₂) with ene‐terminated hyperbranched polyphosphate acrylate (HPPA).When 2 wt% HPPA‐SH‐mSiO₂ hybrid was added to an epoxy matrix, thermogravimetric analysis (TGA) showed that the incorporation of HPPA‐SH‐mSiO₂ increased the thermal stability of epoxy resin composites. Moreover, the combustion behavior of epoxy composites was investigated using a cone calorimeter, and the results show that the PHRR and THR of EP/HPPA‐SH‐mSiO₂ composites clearly decreased by 28.7% and 16%, respectively. Volatile toxic compounds such as aromatic compounds, CO, carbonyl compounds, and hydrocarbons were identified using TGA‐infrared spectroscopy coupling technique. The effect of HPPA‐SH‐mSiO₂ hybrids on the removal of toxic volatiles was also investigated. Functionalized mesoporous silica and polymer composites have potential applications.     

The crystal and molecular structure of a trifluoroacetylacetonate complex of scandium,Sc(CH<Subscript>3</Subscript>COCHCOCF<Subscript>3</Subscript>)<Subscript>3</Subscript>

The crystal and molecular structure of Sc(CH₃COCHCOCF₃)₃ has been determined by X-ray diffraction. The compound crystallizes as pure mer-isomer in the orthorhombic space group Pbca with lattice parameters a=15.166(8) ?, b=13.560(7) ?, c=19.327(10) ?, α=β=γ=90°, V=3974(4) ?³, Z=8. The complex at 100 K is partially disordered in the crystal structure in an approximate 5:1 ratio with 83% fluorine population at C-11 and 17% at C-15. NMR data is compared to that previously reported.     

A Chain Structure Based on Homodinuclear Scandium Units: [Sc(μ-OH)(2,5-pydc)(H2O)]n

The reaction of pyridine-2,5-dicarboxylic acid with Sc2O3 under hydrothermal con-dition yields a new complex [Sc(μ-OH)(2,5-pydc)(H2P)]n 1 which has a chain structure based on homodinuclear scandium units. Crystal data for 1: space group P1, a = 6.7192(13), b = 7.6131(13),c= 8.9313(14) A, α = 95.976(6), β = 101.663(6),γ,= 108.151(5)°, V = 418.26(13) A3, Z = 2, Dc =1.946 g/cm3,μ = 0.889 mm-1, F(000) = 248, C7H6NO6Sc, M, = 245.09, the final R = 0.0429 and wR = 0.1086.     

A Chain Structure Based on Homodinuclear Scandium Units： [Sc（μ-OH）（2,5-pydc）（H2O）]n

The reaction of pyridine-2,5-dicarboxylic acid with Sc2O3 under hydrothermal con- dition yields a new complex [Sc（μ-OH）（2,5-pydc）（H2O）]n 1 which has a chain structure based on homodinuclear scandium units. Crystal data for 1： space group P^-1, a = 6.7192（13）, b = 7.6131（13）, c = 8.9313（14） A, α = 95.976（6）, β = 101.663（6）, γ = 108.151（5）^o, V= 418.26（13） A^3, Z = 2, Dc = 1.946 g/cm^3, g = 0.889 mm^-1, F（000） = 248, C7H6NO6Sc, Mr = 245.09, the final R = 0.0429 and wR = 0.1086.