Intramolecular rearrangements guided by adaptive coordination-driven reactions toward highly luminescent polynuclear Cu(i) assemblies

Highly luminescent solid-state Cu6, Au2Cu10 and Pt4Cu11 derivatives are obtained in one step reaction thanks to adaptive coordination-driven supramolecular chemistry using pre-assembled flexible Cu(i) precursors.

Structures in multiple conformations reveal distinct transition metal and proton pathways in an Nramp transporter

Nramp family transporters—expressed in organisms from bacteria to humans—enable uptake of essential divalent transition metals via an alternating-access mechanism that also involves proton transport. We present high-resolution structures of Deinococcus radiodurans (Dra)Nramp in multiple conformations to provide a thorough description of the Nramp transport cycle by identifying the key intramolecular rearrangements and changes to the metal coordination sphere. Strikingly, while metal transport requires cycling from outward- to inward-open states, efficient proton transport still occurs in outward-locked (but not inward-locked) DraNramp. We propose a model in which metal and proton enter the transporter via the same external pathway to the binding site, but follow separate routes to the cytoplasm, which could facilitate the co-transport of two cationic species. Our results illustrate the flexibility of the LeuT fold to support a broad range of substrate transport and conformational change mechanisms.

Structures in multiple conformations reveal distinct transition metal and proton pathways in an Nramp transporter

Nramp family transporters—expressed in organisms from bacteria to humans—enable uptake of essential divalent transition metals via an alternating-access mechanism that includes proton co-transport. We present high-resolution structures ofDeinococcus radiodurans(Dra)Nramp at complementary stages of its transport cycle to provide a thorough description of the Nramp transport cycle by identifying the key intramolecular rearrangements and changes to the metal coordination sphere. Strikingly, while metal transport requires cycling from outward-to inward-open states, efficient proton transport still occurs in outward-locked (but not inward-locked) DraNramp. We propose a model in which metal and proton enter the transporter via the same external pathway to the binding site, but follow separate routes to the cytoplasm, thus resolving the electrostatic dilemma of using a cation co-substrate to drive a cation primary substrate. Our results illustrate the flexibility of the LeuT fold to support a broad range of co-substrate coupling and conformational change mechanisms.

Synthesis of new A-conjugated Quinolone and Spiroindole Dammaranes by the Ozonolysis of 2,3-Indolodipterocarpol

An one-step and efficient access to the new dammarane A-quinolones by ozonolysis of 2,3-indolodipterocarpol at 0°C through the 1,3-dipolar cycloaddition of ozone to the C2-C3 double bond of the triterpenoid core is reported. In the case of oxidation in AcOH, two spiroindoles were identified as a result of 1,2-cycloaddition of ozone to the C2-C3 double bond with following intramolecular rearrangements of 2,3-epoxy-intermediate. The structures of four new compounds were established by 1H, 13C NMR, COSY, NOSY, HMBC and HSQC analyses.

Unimolecular decomposition of formamide via direct chemical dynamics simulations

Classical chemical dynamics simulations show that formamide (NH2CHO) can dissociate via multiple pathways, either by direct dissociations or via intramolecular rearrangements to different isomers followed by dissociation.

Quantum chemical modeling of magnetically bistable metal coordination compounds. Synchronization of spin crossover, valence tautomerism and charge transfer induced spin transition mechanisms

Heterometallic complexes of 1,10-phenanthroline-5,6-dione exhibiting unprecedented dynamic behaviour due to synchronized thermally induced intramolecular rearrangements were computationally studied.