Facet engineering of oxide nanocrystals represents a powerful method for generating diverse properties for practical and innovative applications. Therefore, it is crucial to determine the nature of the exposed facets of oxides in order to develop the facet/morphology–property relationships and rationally design nanostructures with desired properties. Despite the extensive applications of electron microscopy for visualizing the facet structure of nanocrystals, the volumes sampled by such techniques are very small and may not be representative of the whole sample. Here, we develop a convenient 17O nuclear magnetic resonance (NMR) strategy to distinguish oxide nanocrystals exposing different facets. In combination with density functional theory calculations, we show that the oxygen ions on the exposed (001) and (101) facets of anatase titania nanocrystals have distinct 17O NMR shifts, which are sensitive to surface reconstruction and the nature of the steps on the surface. The results presented here open up methods for characterizing faceted nanocrystalline oxides and related materials.

S = 1 /2 kagome lattice antiferromagnets (KLAFs) have attracted great interest since they are closely associated with the long-sought quantum spin liquid (QSL) state. The realization of S = 1/2 KLAF remains an outstanding challenge and efforts have focused principally on Cu2+, d9 compounds. Herein, the synthesis of the first structurally perfect d1 KLAF, (CH3NH3)2NaTi3F12, is presented. The trivalent oxidation state and the Jahn-Teller distortion of Ti3+ ions are probed by single crystal X-ray diffraction, X-ray photoelectron spectroscopy, and UV-vis-NIR diffuse reflectance. No structural phase transitions can be observed from 1.8 K to 523 K. However, a glass transition can be observed due to the disordered, interlayer CH3NH3+ cations.The Curie-Weiss temperature, θcw= -139.5(7) K, and the lack of long-range ordering in magnetic susceptibility and specific heat imply that this compound is a QSL candidate. File list (2)download file view on ChemRxiv MA2NaTi3F12_Main-Text_CR.pdf (906.77 KiB) download file view on ChemRxiv MA2NaTi3F12_Supp_Info_CR.pdf (1.90 MiB)

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The recent isolation of molecular tetravalent lanthanide complexes has enabled renewed exploration of the effect of oxidation state on the single-ion properties of the lanthanide ions. Despite the isotropic nature of the 8S ground state in a tetravalent terbium complex, [Tb­(NP­(1,2-bis- t Bu-diamidoethane)­(NEt2))4], preliminary X-band electron paramagnetic resonance (EPR) measurements on tetravalent terbium complexes show rich spectra with broad resonances. The complexity of these spectra highlights the limits of conventional X-band EPR for even qualitative determination of zero-field splitting (ZFS) in these complexes. Therefore, we report the synthesis and characterization of a novel valence series of 4f7 molecular complexes spanning three oxidation states (Eu2+, Gd3+, and Tb4+) featuring a weak-field imidophosphorane ligand system, and employ high-frequency and -field electron paramagnetic resonance (HFEPR) to obtain quantitative values for ZFS across this valence series. The series was designed to minimize deviation in the first coordination sphere from the pseudotetrahedral geometry in order to directly interrogate the role of metal identity and charge on the complexes’ electronic structures. These HFEPR studies are supported by crystallographic analysis and quantum-chemical calculations to assess the relative covalent interactions in each member of this valence series and the effect of the oxidation state on the splitting of the ground state and first excited state.

ABSTRACT. We aimed to evaluate the influence of four SNPs in ERCC1 and ERCC2 on the response to cisplatin-based treatment and on clinical outcome in patients with osteosarcoma. We identified 186 patients with osteosarcoma diagnosed between April 2009 and April 2011 who were eligible for inclusion in our study. Genotyping of ERCC1 rs11615, rs3212986, and rs2298881; and ERCC2 rs1799793 and rs13181 was conducted by a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. By conditional logistic regression analysis, patients carrying the CC genotypes of ERCC1 rs11615 and rs2298881 were shown to be more likely to have good response to chemotherapy when compared with patients carrying wildtype genotypes; the ORs (95%CIs) were 2.56 (1.02-7.35) and 3.01 (1.07-9.71), respectively. By Cox regression analysis, individuals carrying the CC genotype of ERCC1 rs11615 were associated with longer overall survival time and decreased risk of death from osteosarcoma; the hazards 10146 Z.H. Cao et al. ©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 14 (3): 10145-10151 (2015) ratio (95%CI) was 0.32 (0.07-0.98). In summary, our results suggested that the ERCC1 rs11615 and rs2298881 polymorphisms play important roles in the response to chemotherapy mediated by the DNA repair pathway and in the clinical outcome of osteosarcoma.