Halide

Explorations of new stable lead free perovskites have currently achieved substantial interest in the field of photovoltaics and optoelectronics as it tries to overcome the instability issue and avoid toxicity related with the lead based perovskites. We herein not only comprehensively tried to explain the experimentally synthesized two inorganic halide double perovskite materials but exploring their broader structural stability and also provide us a guideline to better understand their possible potential applications. For this purpose we performed density functional theory to investigate the structural, electronic, optical, elastic and thermoelectric properties of these materials. The stability of these cubic materials is validated by optimizing the structure, from the tolerance factor, mechanical stability test. These materials are found to be small band gap semiconductors with outshining optoelectronic performance. Due to high optical absorption, high conductivity and low reflectiv...

Nitrate isotopic values are often used as a tool to understand sources of contamination in order to effectively
manage groundwater quality. However, recent literature describes that biogeochemical reactions may modify
these values. Therefore, data interpretation is difficult and often vague. We provide a discussion on this topic
and complement the study using halides as comparative tracers assessing an aquifer underneath a sub-humid
to humid region in NE Mexico. Hydrogeological information and stable water isotopes indicate that active
groundwater recharge occurs in the 8000km2 study area under present-day climatic and hydrologic conditions.
Nitrate isotopes and halide ratios indicate a diverse mix of nitrate sources and transformations. Nitrate sources
include organic waste and wastewater, synthetic fertilizers and soil processes. Animal manure and sewage
from septic tanks were the causes of groundwater nitrate pollution within orchards and vegetable agriculture.
Dairy activities within a radius of 1000m from a sampling point significantly contributed to nitrate pollution.
Leachates from septic tanks caused nitrate pollution in residential areas. Soil nitrogen and animal waste were
the sources of nitrate in groundwater under shrubland and grassland. Partial denitrification processes helped
to attenuate nitrate concentration underneath agricultural lands and grassland, especially during summer
months.

ABSTRACT The oxidation of [Sm(DippForm)2(thf)2] (1; DippFormH = N,N′-bis(2,6-diisopropylphenyl)formamidine) by tert-butyl chloride, 1,2-dibromoethane, and iodine, respectively, at ambient temperature led to the isolation of the light yellow crystalline samarium(III) halide complexes [Sm(DippForm)2X(thf)] (2, X = Cl; 3, X = Br; 4, X = I) in good yield. The subsequent metathesis reaction of [Ln(DippForm)2X(thf)] (2, Ln = Sm, X = Cl; Ln = La, X = F) with LiMe and LiCH2SiMe3 generated the samarium alkyl complexes [Sm(DippForm)2R(thf)] (5, R = Me; 6, R = CH2SiMe3) and the rare terminal La–Me complex [La(DippForm)2Me(thf)] (7). The attempted ligand exchange reaction of 7 with 1,2,3,4-tetraphenylcyclopentadiene gave, unexpectedly, the homoleptic tris(formamidinato)lanthanum complex [La(DippForm)3] (8) in very low yield. The redox transmetalation/protolysis (RTP) reaction from samarium metal with bis(2-bromo-3,4,5,6-tetrafluorophenyl)mercury and DippFormH in thf yielded the mono(formamidinato)samarium(III) complex [Sm(DippForm)Br2(thf)3] (9) as a coproduct with the bis(formamidinate) 3. Redox reaction of the divalent samarium complex [Sm(DippForm)2(thf)2] (1) with diphenylmercury resulted in the ethenolate complex [Sm(DippForm)2(OCH═CH2)(thf)] (10) instead of the target Sm–Ph complex, the product resulting from the decomposition of Lewis base thf molecules.

Echoing the roaring success of their bulk counterparts, nano-objects built from organolead halide perovskites (OLHP) present bright prospects for surpassing the performances of their conventional organic and inorganic analogues in photodriven technologies. Unraveling the photoinduced charge dynamics is essential for optimizing the optoelectronic functionalities. However, mapping the carrier-lattice interactions remains challenging, owing to their manifestations on multiple length scales and time scales. By correlating ultrafast time-resolved optical and X-ray absorption measurements, this work reveals the photoinduced formation of strong-coupling polarons in CH3NH3PbBr3 nanoparticles. Such polarons originate from the self-trapping of electrons in the Coulombic field caused by the displaced inorganic nuclei and the oriented organic cations. The transient structural change detected at the Pb L3 X-ray absorption edge is well-captured by a distortion with average bond elongation in the ...

A condensation reaction between 1,2-diphenylethane-1,2-dione dihydrazone (DPEDDH) and dimethyl or diethyloxalate in methanol resulted in a novel Schiff base octaazamacrocyclic ligand, (L): (6,7,14,15-tetraoxa-2,3,10,11-tetraphenyl-1,4,5,8,9,12,13,16-octaazacyclohexadecane-1,3,9,11-tetraene). Subsequently metal complexes of the type [MLX2] and [CuL]X2; (M=Mn(II), Co(II), Ni(II) and Zn(II); X=Cl or NO3) were synthesized by the reaction of the free macrocyclic ligand (L) with the corresponding metal salts in 1:1 molar ratio. These complexes were characterized on the basis of analytical data, molar conductivity and magnetic susceptibility measurements, ESI-mass, IR, NMR ((1)H and (13)C), EPR and electronic spectral studies. The thermal stability of the complexes was also studied by TGA and DTA analyses. These studies show that all the complexes have octahedral arrangement around the metal ions except copper complexes which are square planar. The ligand and its complexes were screened fo...

We report herein an effective method for the halogenation of imidazo-fused heterocycles using readily available sodium salts (NaCl/NaBr/NaI) as halogen source and K2S2O8 (or) oxone as promoter. A variety of C-3 halogenated imidazo[1,2-a]pyridines and benzo[d]imidazo[2,1-b]thiazoles were obtained in good to excellent yields. The present method of halogenation has been also extended to 2-aminopyridines, 2-aminopyrimidine, indole and isoquinoline with moderate to excellent yields.