Synthesis and characterisation of some main-group compounds with bulky electron-withdrawring substituents

Several new group 13, 14 and 15 derivatives with the ligands 2,4,6-(CF(_3))(_3)C(_6)H(_2) (Ar), 2,6- (CF(_3))(_2)C(_6)H(_3) (Ar') and / or 2,4-(CF(_3))(_2)C(_6)H(_3) (Ar") have been prepared. They have been characterised by multinuclear NMR spectroscopy and, for all isolated compounds, by elemental analysis and, where possible, single crystal X-ray diffraction. Reaction of ArLi or the mixture Ar'Li/Ar"Li with BCI3 has led to the characterisation of several mono- and disubstituted compounds, but attempted substitution in AICI3 was unsuccessful. Reaction of EC1(_4) (E = Si, Ge, Sn) with the Ar'Li/Ar"Li mixture yielded predominantly the less sterically hindered disubstituted product Ar"(_2)ECl(_2) for E = Si and Ge but to Ar'(_2)ECl(_2) for E = Sn. In the case of B or Si, chlorine exchange is observed and Ar(_2)BF, Ar(_2)SiF(_2) and Ar'(_2)SiF(_2) have been synthesised. Ar(_2)SiF(_2) is the only product identified in the reaction of ArLi with SiC1(_4). Reaction of ArLi or the Ar'Li/Ar"Li mixture, in an appropriate ratio, with group 15 derivatives gave rise to several mono-or disubstituted compounds of the type ArEX(_2), Ar(_2)EX, Ar'EX(_2), Ar"EX(_2), Ar"(_2)EX and Ar'Ar"EX (E = P or As; X = H, CI or Br). (^19)F NMR spectra of Ar'Ar"EX show that, for the two ortho-CF(_3) groups of the Ar' moiety, there is free rotation of the aryl group around the central atom. A series of variable temperature studies has been carried out, and allowed the determination of the rotational energy barrier of the molecule. For the first time, the molecular structures of derivatives containing three fluoroxyl ligands have been determined (Ar"(_3)B and Ar'Ar"(_2)Sb).The synthesis of some new platinum complexes has been facilitated by reaction of phosphanes with the platinum dimer [(PtCl(_2)(Pet(_3))](_2) or [(PtBr(_2)(Pet(_3))](_2). Reactions of the platinum dimer with arsane derivatives have not been successful. Halogen exchange was observed between bromophosphane ligands and CI groups on the platinum. Attempts have been made to synthesise new P=E derivatives containing the electron- withdrawing substituents Ar or Ar' via reaction with the chlorine abstractor W(PMe(_3))(_6)- ArP=PAr and Ar'P=PAr' have been prepared. Synthesis of the first phosphaalkyne containing Ar or Ar' has been attempted by reacting a phosphaalkene with a Pt(0) species

Augmented Reticular Thalamic Bursting and Seizures in Scn1a-Dravet Syndrome

Loss of function in the Scn1a gene leads to a severe epileptic encephalopathy called Dravet syndrome (DS). Reduced excitability in cortical inhibitory neurons is thought to be the major cause of DS seizures. Here, in contrast, we show enhanced excitability in thalamic inhibitory neurons that promotes the non-convulsive seizures that are a prominent yet poorly understood feature of DS. In a mouse model of DS with a loss of function in Scn1a, reticular thalamic cells exhibited abnormally long bursts of firing caused by the downregulation of calcium-activated potassium SK channels. Our study supports a mechanism in which loss of SK activity causes the reticular thalamic neurons to become hyperexcitable and promote non-convulsive seizures in DS. We propose that reduced excitability of inhibitory neurons is not global in DS and that non-GABAergic mechanisms such as SK channels may be important targets for treatment.In a mouse model of Dravet syndrome (DS) resulting from voltage-gated sodium channel deficiency, Ritter-Makinson et al. find that inhibitory neurons of the reticular thalamic nucleus are paradoxically hyperexcitable due to compensatory reductions in a potassium SK current. Boosting this SK current treats non-convulsive seizures in DS mice

CCDC 654398: Experimental Crystal Structure Determination

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures

CCDC 654396: Experimental Crystal Structure Determination

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures

CCDC 654397: Experimental Crystal Structure Determination

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures

The Reaction Chemistry of Plutonyl(VI) Chloride Complexes with Triphenyl Phosphineoxide and Triphenyl Phosphinimine

The reaction between Ph3PO dissolved in acetone and "PuO2Cl2" in dilute HCl resulted in the formation of [PuO2Cl2(Ph3PO)(2)]. Crystallographic characterization of the acetone solvate revealed the expected axial trans plutonyl dioxo, with trans Cl and Ph3PO in the equatorial plane. Spectroscopic analyses (P-31 NMR, H-1 NMR, and vis/nlR) indicate the presence of both cis and trans isomers in solution, with the trans isomer being more stable. Confirmation of the higher stability of the trans versus cis isomers for [AnO(2)Cl(2)(Ph3PO)(2)] (An = U and Pu) was obtained through quantum chemical computational analysis, which also reveals the Pu-O-TPPO bond to be more ionic than the U-O-TPPO bond. Slight variation in reaction conditions led to the crystallization of two further minor products, [PuO2(Ph3PO)(4)][ClO4](2) and cis-[PuCl2(Ph3PO)(4)], the latter complex revealing the potential for reduction to Pu-IV. In addition, the reaction of Ph3PNH with [PuO2Cl2(thf)(2)](2) in anhydrous conditions gave evidence for the formation of both cis- and trans-[PuO2Cl2(Ph3PNH)(2)] in solution (by P-31 NMR). However, the major reaction pathway involved protonation of the ligand with the crystallographic characterization of [Ph3PNH2](2)[PuO2Cl4]. We believe that HCl/SiMe3Cl carried through from the small scale preparation of [PuO2Cl2(thf)(2)](2) was the source of both protons and chlorides. The fact that this chemistry was significantly different from previous uranium studies, where cis-/trans-[UO2Cl2L2] (L = Ph3PO or Ph3PNH) were the only products observed, provides further evidence of the unique challenges and opportunities associated with the chemistry of plutonium