Impact of flexible succinate connectors on the formation of tetrasulfonylcalix[4]arene based Nano-sized polynuclear cages: structural diversity and induced chirality study

The building of new Supramolecular Coordination Containers obtained through the linking of tetrasulfonylcalix[4]arene (3-4H) based transition metal tetra- or trinuclear clusters by succinic acid (suc) as a flexible aliphatic connector...

Trinuclear NiII-LnIII-NiII Complexes with Schiff Base Ligands: Synthesis, Structure, and Magnetic Properties

The reaction of the Schiff base ligand o-OH-C6H4-CH=N-C(CH2OH)3, H4L, with Ni(O2CMe)2∙4H2O and lanthanide nitrate salts in a 4 : 2 : 1 ratio lead to the formation of the trinuclear complexes [Ni2Ln(H3L)4(O2CMe)2](NO3) (Ln = Sm (1), Eu (2), Gd (3), Tb (4)). The complex cations contain the strictly linear NiII-LnIII-NiII moiety. The central LnIII ion is bridged to each of the terminal NiII ions through two deprotonated phenolato groups from two different ligands. Each terminal NiII ion is bound to two ligands in distorted octahedral N2O4 environment. The central lanthanide ion is coordinated to four phenolato oxygen atoms from the four ligands, and four carboxylato oxygen atoms from two acetates which are bound in the bidentate chelate mode. The lattice structure of complex 4 consists of two interpenetrating, supramolecular diamond like lattices formed through hydrogen bonds among neighboring trinuclear clusters. The magnetic properties of 1-4 were studied. For 3 the best fit of the magnetic susceptibility and isothermal M(H) data gave JNiGd = +0.42 cm−1, D = +2.95 cm−1 with gNi = gGd = 1.98. The ferromagnetic nature of the intramolecular Ni···Gd interaction revealed ground state of total spin S = 11/2. The magnetocaloric effect (MCE) parameters for 3 show that the change of the magnetic entropy (−ΔSm) reaches a maximum of 14.2 J kg−1 K−1 at 2 K. A brief literature survey of complexes containing the NiII-LnIII-NiII moiety is discussed in terms of their structural properties.

Balancing volumetric and gravimetric uptake in highly porous materials for clean energy

A huge challenge facing scientists is the development of adsorbent materials that exhibit ultrahigh porosity but maintain balance between gravimetric and volumetric surface areas for the onboard storage of hydrogen and methane gas—alternatives to conventional fossil fuels. Here we report the simulation-motivated synthesis of ultraporous metal–organic frameworks (MOFs) based on metal trinuclear clusters, namely, NU-1501-M (M = Al or Fe). Relative to other ultraporous MOFs, NU-1501-Al exhibits concurrently a high gravimetric Brunauer−Emmett−Teller (BET) area of 7310 m2 g−1 and a volumetric BET area of 2060 m2 cm−3 while satisfying the four BET consistency criteria. The high porosity and surface area of this MOF yielded impressive gravimetric and volumetric storage performances for hydrogen and methane: NU-1501-Al surpasses the gravimetric methane storage U.S. Department of Energy target (0.5 g g−1) with an uptake of 0.66 g g−1 [262 cm3 (standard temperature and pressure, STP) cm−3] at 100 bar/270 K and a 5- to 100-bar working capacity of 0.60 g g−1 [238 cm3 (STP) cm−3] at 270 K; it also shows one of the best deliverable hydrogen capacities (14.0 weight %, 46.2 g liter−1) under a combined temperature and pressure swing (77 K/100 bar → 160 K/5 bar).

Kinetic Versus Thermodynamic Metalation Enables Synthesis of Isostructural Homo- and Heterometallic Trinuclear Clusters

Temperature-dependent metalation of the new hexadentate ligand (tris(5-(pyridin-2-yl)-1<i>H</i>-pyrrol-2-yl)methane; H₃TPM) enables the selective synthesis of both mononuclear (<i>i.e. </i>Na(THF)₄[Fe(TPM)], kinetic product) and trinuclear (<i>i.e.</i> Fe₃(TPM)₂, thermodynamic product) complexes. Exposure of Na(THF)₄[Fe(TPM)] to FeCl₂ or ZnCl₂ triggers cluster expansion to generate homo- or heterometallic trinuclear complexes, respectively. The developed approach enables systematic variation of ion content in isostructural metal clusters via programmed assembly.

Kinetic Versus Thermodynamic Metalation Enables Synthesis of Isostructural Homo- and Heterometallic Trinuclear Clusters

Temperature-dependent metalation of the new hexadentate ligand (tris(5-(pyridin-2-yl)-1<i>H</i>-pyrrol-2-yl)methane; H₃TPM) enables the selective synthesis of both mononuclear (<i>i.e. </i>Na(THF)₄[Fe(TPM)], kinetic product) and trinuclear (<i>i.e.</i> Fe₃(TPM)₂, thermodynamic product) complexes. Exposure of Na(THF)₄[Fe(TPM)] to FeCl₂ or ZnCl₂ triggers cluster expansion to generate homo- or heterometallic trinuclear complexes, respectively. The developed approach enables systematic variation of ion content in isostructural metal clusters via programmed assembly.

Kinetic versus thermodynamic metalation enables synthesis of isostructural homo- and heterometallic trinuclear clusters

Temperature-dependent metalation of a new hexadentate enables the selective synthesis of both mononuclear (i.e. kinetic product) and trinuclear (i.e. thermodynamic product) complexes.

Reaction of carbonyl trinuclear clusters with 2,5-bis(2-thienyl)-1-phenyl-phosphole as a ligand: a new pathway to ruthenacyclopentadiene and cyclopentadienone ruthenium complexes

A novel pathway for the formation of ruthenacyclopentadiene and cyclopentadienone ruthenium complexes is described.