Diverse Reactions of α-Diimine-Ligated MgI -MgI -Bonded Compound with Carbodiimides.

The α-diimine-ligated dimagnesium(I) compound [K(thf)3 ]2 [LMg-MgL] (1, L=[(2,6-iPr2 C6 H3 )NC(Me)]2 2- ) displays diverse reactivities toward carbodiimides (RN=C=NR) with different R substituents. In the reaction of 1 with Me3 SiNCNSiMe3 , one of the easily leaving trimethylsilyl groups is lost to yield the Me3 SiNCN- moiety that either bridges two MgII centers (2) or terminally coordinated (3). In contrast, with the similarly bulky tBuNCNtBu, the carbodiimide inserts into Mg-Mg bond with accompanying C-H activation of a ligand or solvent (products 4 and 5). In the case of dicyclohexyl or diisopropyl carbodiimide, reductive C-C coupling of two RNCNR molecules occurs to form the [C2 (NR)4 ]2- diamido moiety, which bridges two Mg centers, giving complexes [{K(dme)2 }2 LMg(µ-{C2 (NR)4 })MgL] (6, R=Cy; 7, R=iPr) and [L⋅- Mg(µ-{C2 (NR)4 })MgL⋅- ] (8). Most interestingly, upon treating 1 with Me3 SiC≡CSiMe3 , the acetylide complex [K(dme)][LMg(C≡CSiMe3 )(dme)] (9) was prepared, which undergoes a rare "double insertion" with CyNCNCy to afford [K(solv)][K(dme)2 LMg(NCy)2 C-C≡C-C(NCy)2 MgL] (10) containing an acetylenediide-coupled bis(amidinate) ligand that bridges two Mg atoms.

Synthesis and structure of a new trinuclear nickel(II) complex bridged by N-[3-(Dimethylamino)propyl]-N'-(2-hydroxyphenyl)oxamido: in vitro anticancer activities, and reactivities toward DNA and protein.

A new trinickel(II) complex bridged by N-[3-(dimethylamino)propyl]- N'-(2-hydroxylphenyl)oxamido (H3 pdmapo), namely [Ni3 (pdmapo)2 (H2 O)2 ]⋅4CH3 OH, was synthesized and characterized by X-ray single-crystal diffraction and other methods. In the molecule, two symmetric cis-pdmapo3- mononickel(II) complexes as a "complex ligand" using the carbonyl oxygen atoms coordinate to the center nickel(II) ion situated on an inversion point. The Ni···Ni distance through the oxamido bridge is 5.2624(4) Å. The center nickel(II) ion and the lateral ones have octahedral and square-planar coordination geometries, respectively. In the crystal, a three-dimensional supramolecular network dominated by hydrogen bonds is observed. The reactivity toward DNA/protein bovine serum albumin (BSA) revealed that the complex could interact with herring sperm DNA (HS-DNA) through the intercalation mode and quench the intrinsic fluorescence of BSA via a static mechanism. The in vitro anticancer activities suggested that the complex is active against the selected tumor cell lines.

Associations between tobacco and alcohol use and aggressive behavior among adolescents in 55 Low- and Middle-Income countries.

BACKGROUND: Aggressive behavior has become a serious public health problem among adolescents worldwide. We aimed to assess the associations between tobacco and alcohol use and aggressive behavior among adolescents in 55 Low- and Middle-Income countries (LMICs). METHODS: Data from 55 LMICs that had done a Global School-based Student Health Survey (GSHS) between 2009 and 2017, comprising 187,787 adolescents aged 12-17 years, were used to examine the associations between tobacco and alcohol use and aggressive behavior. RESULTS: Among adolescents in the 55 LMICs, the proportion of aggressive behavior was 5.7 %. Compared with none tobacco users, those who used tobacco on 1-5 days (odds ratio [OR] = 2.00, 95 % confidence interval [CI] = 1.89-2.11), 6-9 days (2.76, 2.48-3.08), 10-19 days (3.20, 2.88-3.55), and ≥20 days (3.88, 3.62-4.17) during the past 30 days were positively associated with aggressive behavior. Compared with none alcohol users, those who used alcohol on 1-5 days (1.44, 1.37-1.51), 6-9 days (2.38, 2.18-2.60), 10-19 days (3.04, 2.75-3.36), and ≥20 days (3.25, 2.93-3.60) during the past 30 days were positively associated with aggressive behavior. LIMITATIONS: Aggressive behavior, tobacco use and alcohol use were assessed by self-reported questionnaires, which might be prone to recall bias. CONCLUSIONS: Higher amounts of tobacco and alcohol use are associated with aggressive behavior among adolescents. These findings emphasize the need to strengthen tobacco and alcohol control efforts to reduce tobacco and alcohol use targeting adolescents in LMICs.

Mg-Mg-bonded compounds with N,N'-dipp-substituted phenanthrene-diamido and o-phenylene-diamino ligands.

Two Mg-Mg-bonded compounds were synthesized by using the ligands N,N'-bis(dipp)-phenanthrene-9,10-diimine (L2) and N,N'-bis(dipp)-o-phenylenediamine (H2L3; dipp = 2,6-diisopropylphenyl). These new Mg(i) species were characterized by X-ray diffraction, NMR, UV-Vis and fluorescence spectroscopy, and DFT computations. Their reactions with unsaturated organic molecules were examined.

The associations of heavy metals with crystalline iron oxides in the polluted soils around the mining areas in Guangdong Province, China.

In current selective sequential extraction (SSE) methods, heavy metals associated well-crystallized iron oxyhydroxides are not well defined and considered, and usually fall into residual forms, which actually make their mobility and environmental risk underestimated. This study compared various fractions of heavy metals in samples of mining tailings and nearby soils under different land uses in Guangdong Province of China. Iron oxides in these soils were mainly Al-substituted goethites and/or hematites. Independent of the land uses, the percentages of various Cd fractions in the soils decrease in the order of well-crystallized iron oxyhydroxides-associated (27.2-91.2%) > residual (2.1-37.0%) > reducible FeMn oxides (3.2-45.7%) > exchangeable (1.0-28.2%) > organic-associated form (0-5.1%). Pb mainly existes in the residual fraction (25.9-74.5%), followed by crystalline iron oxyhydroxides-associated (0.4-69.0%) and reducible fractions (2.4-40.4%). Zn mainly exists in the residual fraction (25.4-85.9%), followed by the well-crystallized iron oxyhydroxides-associated fraction (6.4-55.0%). However, Cu mainly existes in the residual form and the fractionation of Cu varies obviously between samples. The association of these metals with crystalline iron oxyhydroxides in the soils decreases in the sequence of Cd > Pb > Zn > Cu. These results suggest that in heavy-metal-polluted weathered soils in tropical and subtropical areas enriched with iron oxides, it is essential to assess potential bioavailability and toxicity of heavy metals bound to well-crystallized iron oxyhydroxides with appropriate procedures in the fractionation measurement. The modified Tessier method present here can be used to quantify the fractions of heavy metals in such areas.