金属冠醚的合成进展

金属冠醚是一类新型的超分子大环化合物, 它开拓了主客体化学分子识别和超分子化学的全新领域. 综述了近年来金属冠醚的研究成果.     

A mild and efficient CAN mediated oxidation of Morita-Baylis-Hillman adducts of 5-methyl-N-alkylisatin to 5-formyl-N-alkylisatin

A simple, mild and efficient CAN mediated oxidation of Morita-Baylis-Hillman adducts of 5-methyl-N-alkylisatins 1a-13a to 5-formyl-N-alkylisatins 1b-13b under ambient reaction conditions is reported. Simple and isomerized 5-methyl-N-alkylisatin derivatives 1-4 have also been tested and failed to provide the corresponding formylated products. A plausible reaction mechanism has been proposed.     

Organocatalytic (1+4)-Annulations of MBH Adducts with Electron-Deficient Systems

Benefited from the rapid development of MBH reaction, the reaction of MBH adducts have been established as the most synthetically useful transformations. However, compared with the well-established allylic alkylations and (3+2)-annulations, the (1+4)-annulations of MBH adducts have not developed rapidly until recently. As a helpful complement to the (3+2)-annulations of MBH adducts, the (1+4)-annulations of MBH adducts opens a robust access to structurally diverse five-membered carbo- and heterocycles. This paper summarizes recent advances in organocatalytic (1+4)-annulations using MBH adducts as 1 C-synthons for the construction of functionalized five-membered carbo- and heterocycles.     

Crystal structure of [ethylenediamine-<Emphasis Type="Italic">N,N</Emphasis>′-di(3-propionato)copper(II)]-<Emphasis Type="Italic">tris</Emphasis>[dichloromercury(II)] [Cu(Eddp)·(HgCl<Subscript>2</Subscript>)<Subscript>3</Subscript>]<Subscript>n</Subscript>

Crystals of [Cu(Eddp)·(HgCl₂)₃]_n (monoclinic, a = 9.7547(7) Å, b = 18.3716(12) Å, c = 11.7811(9) Å, β = 94.828(9)°, Z = 4, space group P2₁/n) are made of infinite sheets involving dimeric complexes [Cu₂(Eddp)₂] interacting with quasi-molecules of HgCl₂ (Hg-Cl 2.29-2.36 Å). In the dimers, copper atoms are squarely surrounded by two N atoms and two O atoms of the ethylendiamine-N,N′-di(3-propionate) anion, and atom from a neighboring Eddp ion in the apical position; the second apical position is occupied by a Cl atom of one of HgCl₂ molecules. Weak Hg-Cl interactions (2.98-3.07 Å) join the molecules of HgCl₂ in almost planar centrosymmetrical Hg₆Cl₁₂ hexamers, and further (Hg-Cl 3.168(3) Å, 3.250(2) Å) in infinite chains of the hexamers. Finally, the dimeric copper complexes are linked to six Hg atoms of four adjacent hexamers by virtue of their oxygen atoms (Hg-O 2.322(8), 2.609(6) Å, 2.730(5) Å).     

Kinetics and mechanism of interaction of Pt(II) complex with bio-active ligands and in vitro Pt(II)-sulfur adduct formation in aqueous medium: bio-activity and computational study

Kinetics of interaction between [Pt(pic)(H₂O)₂](ClO₄)₂, 2 (where pic = 2-aminomethylpyridine) with the selected ligands DL-methionine (DL-meth) and DL-penicillamine (DL-pen) have been studied spectrophotometrically in aqueous medium separately as a function of [2] as well as [ligand], pH and temperature at constant ionic strength. The association equilibrium constants (K_E) for the outer sphere complex formation have been evaluated together with the rate constants for the two subsequent steps. Activation parameters (enthalpy of activation ΔH^≠ and entropy of activation ΔS^≠) were calculated from the Eyring equation. An associative mechanism of substitution is proposed for both reactions on the basis of the kinetic observations, evaluated activation parameters, and spectroscopic data. Structural optimizations, HOMO-LUMO energy calculation, and Natural Bond Orbital (NBO) analysis of 2–4 were carried out with Density Functional Theory. Bonding mode of thiol and thio-ether is confirmed by spectroscopic analyses and NBO calculation. Cytotoxic properties of 2–4 were explored on A549 carcinoma cell lines; DNA-binding properties of the complexes were also investigated by gel electrophoresis.     

Formation of Dialkyl 2‐[3‐Alkoxy‐1‐(alkylimino)‐1‐chloro‐3‐oxopropan‐2‐ylidene]hydrazine‐1,1‐dicarboxylates of α‐(Alkoxycarbonyl)imidoyl Chlorides from PhosphineDiazo Ester Zwitterions and Nef‐Isocyanide Adducts

A novel transformation involving phosphine? diazo ester zwitterions (generated from dialkyl azodicarboxylates with Ph₃P) and α‐(alkoxycarbonyl)imidoyl chlorides (prepared from α‐addition of acyl chlorides to alkyl isocyanides) to afford dialkyl 2‐[3‐alkoxy‐1‐(alkylimino)‐1‐chloro‐3‐oxopropan‐2‐ylidene]hydrazine‐1,1‐dicarboxylates in moderate yields, is described.     

Reply to the Comment on “Realization of Lewis Basic Sodium Anion in the NaBH3− Cluster”

We reply to the comment by S. Pan and G. Frenking who challenged our interpretation of the Na⁻:→BH₃ dative bond in the recently synthesized NaBH₃⁻ cluster. Our conclusion remains the same as that in our original paper ( https://doi.org/10.1002/anie.201907089 and https://doi.org/10.1002/ange.201907089 ). This conclusion is additionally supported by the energetic pathways and NBO charges calculated at UCCSD and CASMP2(4,4) levels of theory. We also discussed the suitability of the Laplacian of electron density (QTAIM) and Adaptive Natural Density Partitioning (AdNDP) method for bond type assignment. It seems that AdNDP yields more sensible results. This discussion reveals that the complex realm of bonding is full of semantic inconsistencies, and we invite experimentalists and theoreticians to elaborate this topic and find solutions incorporating different views on the dative bond.     

Significant Phenomena Observed in the Molecule‐Ion Adduct System of Sodium Arsenite with α‐Cyclodextrin

The data of ¹H nuclear magnetic resonance and molar conductivity prove that there is a molecule‐ion interaction between α‐cyclodextrin (α‐CD) and sodium arsenite (SA), and the interaction site is different from that between β‐CD and SA. The packing mode of α‐CD molecules after adduct with SA is changed from cage to channel type. Several experimental phenomena from thermogravimetric analyses and gas chromatography coupled to time‐of‐flight mass spectrometry measurements reveal that the presence of SA has led to a large change of thermal decomposition behavior of α‐CD, and vice versa. The current work reveals the particularity of the interaction between SA and α‐CD, which would provide new insight into the understanding of molecule‐ion interactions.     

两种钴离子支撑钼磷多金属氧酸盐的水热合成及晶体结构

利用水热技术合成了2个新型钴支撑的磷钼多金属氧酸盐超分子化合物:(C2N2H10)5[(P4Mo6O25(OH)6)2Co](1)和(Co(H2O)6)2(C5NH6)6[(P4Mo6O25(OH)6)2Co]·10H2O(2).并通过元素分析、红外光谱、热重分析和X射线单晶衍射对2个化合物进行了表征.结果表明:化合物1属于三斜晶系,P-1空间群;晶胞参数a=1.179 9(2)nm,b=1.337 7(2)nm,c=1.479 7(3)nm,α=73.435(2)°,β=74.383(2)°,γ=66.499(2)°,V=2.020 5(6)nm3,F(000)=1 327,Z=1;化合物2属于属于三斜晶系,P-1空间群;晶胞参数a=1.220 68(11)nm,b=1.381 08(13)nm,c=1.687 18(15)nm,α=92.275(1)°,β=104.774(1)°,γ=114.475(1)°,V=2.468 8(4)nm3,F(000)=1 649,Z=1.