Role of hydrocarbons in pore expansion and contraction of a flexible metal-organic framework

A metal-organic framework obtained from a flexible organic linker shows a breathing phenomenon upon adsorption of saturated hydrocarbons.     

Self-assembly of a Novel One-dimensional Zigzag Coordination Polymer

Abstract

Reaction of anhydrous NiBr₂ with pyrazine and disodium terephthalate in the presence of water results in the formation of a one-dimensional (1D) coordination polymer [Ni(pyrazine)₂(H₂O)₄] · (terephthalate) 1 which demonstrates a linear zigzag coordination pattern running along the crystallographic c-axis. The title compound crystallizes in the monoclinic space group C2/c with a = 16.833(2), b = 9.173(1), c = 11.107(1) Å, β = 119.373(2)°, and D_c = 1.667 for Z = 4. Final refinement based upon 4345 observed reflections led to a final R value of 0.052 for the polymeric product. The included terephthalate anion participates in eight O—H…O hydrogen bonds to coordinated water molecules.     

Phase transition and dynamic structure in the toluene clathrate of t-butylcalix[4]arene

Abstract

Variable temperature solid-state ¹³C NMR and differential scanning calorimetry were used to show that the toluene clathrate of t-butylcalix[4]arene undergoes a symmetry lowering phase transition at 248.0 K. ²H NMR was used to show that the high symmetry of the complex at room temperature is due to dynamic disorder of the toluene guest, which is most easily described as an axial rotor.     

Persicamidines—Unprecedented Sesquarterpenoids with Potent Antiviral Bioactivity against Coronaviruses

A new family of highly unusual sesquarterpenoids (persicamidines A–E) exhibiting significant antiviral activity was isolated from a newly discovered actinobacterial strain, Kibdelosporangium persicum sp. nov., collected from a hot desert in Iran. Extensive NMR analysis unraveled a hexacyclic terpenoid molecule with a modified sugar moiety on one side and a highly unusual isourea moiety fused to the terpenoid structure. The structures of the five analogues differed only in the aminoalkyl side chain attached to the isourea moiety. Persicamidines A–E showed potent activity against hCoV-229E and SARS-CoV-2 viruses in the nanomolar range together with very good selectivity indices, making persicamidines promising as starting points for drug development.     

Reaction of (t-BuGaCl2)2 with Ar′PHLi (Ar′ = 2,4,6-t-Bu3C6H2): Preparation of the chloride-bridged dimer (t-BuGa(Cl)P(H)Ar′)2

The reaction of (t-BuGaCl₂)₂ with Ar′P(H)Li (AR′ = 2,4,6-t-Bu₃C₆H₂) affords the chloride-bridged dimer [t-BuGa(Cl)P(H)Ar′]₂ ( 1 ). The structure of 1 has been established by X-ray crystallography. Compound 1 , C₄₄H₇₈Cl₂Ga₂P₂, crystallizes in the monoclinic space group P2₁/n with Z = 2, a = 10.468(1), b = 14.967(1), c = 16.182(2) Å, and Å = 94.48(1)β. The reaction of 1 with t-BuLi is described.