Marian Olaru

The Weakly Coordinating Tris(trichlorosilyl)silyl Anion

Closely following the procedure for the preparation of the base-stabilized dichlorosilylene complex NHCDipp ⋅SiCl2 reported by Roesky, Stalke, and co-workers (Angew. Chem. Int. Ed. 2009, 48, 5683-5686), a few crystals of the salt [NHCDipp -H⋅⋅⋅Cl⋅⋅⋅H-NHCDipp ]Si(SiCl3 )3 were isolated, aside from the reported byproduct [NHCDipp -H+ ⋅⋅⋅Cl- ], and characterized by X-ray crystallography (NHCDipp =N,N-di(2,6-diisopropylphenyl)imidazo-2-ylidene). They contain the weakly coordinating anion Si(SiCl3 )3- , which was also obtained in high yields upon deprotonation of the conjugate Brønsted acid HSi(SiCl3 )3 with NHCDipp or PMP (PMP=1,2,2,6,6-pentamethylpiperidine). The acidity of HSi(SiCl3 )3 was estimated by DFT calculations to be substantially higher than those of other H-silanes. Further DFT studies on the electronic structure of Si(SiCl3 )3- , including the electrostatic potential and the electron localizability, confirmed its low basicity and nucleophilicity compared with other silyl anions.

(2,4,6-Trimethyl­phen­yl)boronic acid–triphenyl­phosphine oxide (1/1)

In the crystal structure of the title compound, C9H13BO2·C18H15OP, there are O—H⋯O hydrogen bonds between the O atom of triphenylphosphine oxide and one hydroxy group of the boronic acid. Boronic acid molecules form inversion-related hydrogen-bonded dimers in an R 2 2(8) motif. The structure is consolidated by intermolecular C—H⋯O bonds and C—H⋯π interactions.

Heavy Carbene Analogues: Donor-Free Bismuthenium and Stibenium Ions

Kinetically stabilized congeners of carbenes, R2 C, possessing six valence electrons (four bonding electrons and two non-bonding electrons) have been restricted to Group 14 elements, R2 E (E=Si, Ge, Sn, Pb; R=alkyl or aryl) whereas isoelectronic Group 15 cations, divalent species of type [R2 E]+ (E=P, As, Sb, Bi; R=alkyl or aryl), were unknown. Herein, we report the first two examples, namely the bismuthenium ion [(2,6-Mes2 C6 H3 )2 Bi][BArF4 ] (1; Mes=2,4,6-Me3 C6 H2 , ArF =3,5-(CF3 )2 C6 H3 ) and the stibenium ion [(2,6-Mes2 C6 H3 )2 Sb][B(C6 F5 )4 ] (2), which were obtained by using a combination of bulky meta-terphenyl substituents and weakly coordinating anions.

Polymorphisms in autophagy genes and active pulmonary tuberculosis susceptibility in Romania

Abstract Autophagy, a homeostatic process involved in nutrient regeneration and immune responses, may be involved in intracellular killing of M. tuberculosis. Several studies linked variation in autophagy genes with susceptibility to pulmonary tuberculosis, but others did not confirm these findings. We genotyped single nucleotide polymorphisms (SNPs) in the ATG5 (rs2245214, c.574-12777G>C) and NOD2 (rs2066844, c.2104C>T) genes for 256 pulmonary tuberculosis patients and 330 unrelated healthy controls in Romania. Both SNPs have been reported as relevant for the autophagy process and potentially for susceptibility to active pulmonary tuberculosis. In our study, the polymorphisms in ATG5 and NOD2 were not associated with tuberculosis. This suggests that the two genetic variants we focused on are not related to the risk for developing active TB in a Romanian population.

Mapping the Trajectory of Nucleophilic Substitution at Silicon Using a peri-Substituted Acenaphthyl Scaffold

The second-order nucleophilic substitution (SN 2) reaction at a silicon atom is scrutinized by means of snapshots along a pseudoreaction coordinate. Phosphine and fluoride represent both attacking and leaving groups in the modeled SN 2 reaction. In the experimentally obtained 5-diphenylphosphinoacenaphth-6-yl-dimethylfluorosilane, 1, the phosphine and fluorosilane moieties are forced into immediate proximity through an acenaphthyl scaffold, that is, they exhibit peri interactions that serve as the model of the reactant ion-molecule complex and starting point for a theoretical potential-energy surface (PES) scan. Upon dissociation of fluoride, the experimentally obtained silylphosphonium cation 2 serves as a model of the product and end point of the PES scan. The pseudoreaction pathway is studied using geometric, energetic, spectroscopic, molecular-orbital, and topological real-space bonding indicators. It becomes evident that it is crucial to combine such methods to understand the pseudoreaction because they reveal different aspects based on different sensitivity to dispersive, electrostatic, and polar-covalent contributions to bonding, as shown by the reduced density gradient analysis. For example, atoms-in-molecules theory describes a late topological catastrophe, whereas the electron localizability indicator describes an early concerted reaction and natural resonance theory describes a more gradual change of properties. This case study encourages the use of a well-balanced toolbox equipped with complementary methods to emphasize different aspects of bonding.

Correction: The CARD9 polymorphisms rs4077515, rs10870077 and rs10781499 are uncoupled from susceptibility to and severity of pulmonary tuberculosis.

[This corrects the article DOI: 10.1371/journal.pone.0163662.].

Chloridobis{2-[(dimethyl­amino)­meth­yl]phen­yl}anti­mony(III)

In the title compound, [Sb(C9H12N)2Cl], the Sb atom adopts a Ψ-trigonal-bipyramidal geometry. The two 2-[(dimethylamino)methyl]phenyl ligands are coordinated asymmetrically to the Sb atom. The carbon atoms of one of the ligands are disordered over sets of sites with equal occupancy, resulting in two conformational isomers in the crystal. The Sb—C and Sb—N distances in the ordered ligand are: 2.153 (4) and 3.326 (5) Å, respectively. The corresponding distances in the disordered ligand are: 2.103 (5)/2.188 (5) and 2.454 (3) Å, respectively. The structure displays intramolecular C—H⋯Cl hydrogen bonding.

Synthesis and structural characterization of substituted phenols with a m-terphenyl backbone 2,4,6-R3C6H2OH (R=2,4,6-Me3C6H2, Me5C6)

Abstract Substituted phenols with a m-terphenyl backbone 2,4,6-R3C6H2OH [R=2,4,6-Me3C6H2 (1), Me5C6 (2)] were synthesized using Kumada cross-coupling reactions between 2,4,6-I3C6H2OH and the corresponding Grignard reagent. Both compounds were structurally characterized in solution by 1H and 13C NMR spectroscopy and HRMS. The molecular structures of 1 and 2 were determined by single-crystal X-ray diffraction.

2'-Iodo-2,2'',3,3'',4,4'',5,5'',6,6''-deca-methyl-1,1':3',1''-terphenyl chloro-form monosolvate.

The title compound, C28H33I·CHCl3, forms dimers through C—I⋯π interactions. The crystal structure is consolidated by the presence of C—H⋯π interactions between the chloroform solvent and the main molecule.

3,5-Dibromo-2′,3′,4′,5′,6′-penta­methyl-1,1′-biphen­yl

In the crystal structure of the title compound, C17H18Br2, the benzene rings are almost perpendicular [dihedral angle = 84.0 (3)°]. The crystal structure is consolidated by the presence of C—Br⋯π interactions.