Fe III in a low-spin state in caesium bis[3-ethoxysalicylaldehyde 4-methylthiosemicarbazonato(2–)-κ3O2,N1,S]ferrate(III) methanol monosolvate

The synthesis and crystal structure (at 100K) of the title compound, Cs[Fe(C11H13N3O2S2) 2] CH3OH, is reported. The asymmetric unit consists of an octahedral [FeIII(L)2]- fragment, where L 2- is 3-ethoxysalicylaldehyde 4-methylthiosemicarbazonate(2-) {systematic name: [2-(3-ethoxy-2-oxidobenzylidene)hydrazin-1-ylidene] (methylamino)methanethiolate}, a caesium cation and a methanol solvent molecule. Each L2- ligand binds through the thiolate S, the imine N and the phenolate O atoms as donors, resulting in an FeIIIS2N 2O2 chromophore. The O,N,S-coordinating ligands are orientated in two perpendicular planes, with the O and S atoms in cis positions and the N atoms in trans positions. The FeIII cation is in the low-spin state at 100K

Caesium bis­(5-bromo­salicyl­aldehyde thio­semicarbazonato-κ3O,N,S)ferrate(III): supramolecular arrangement of low-spin FeIII complex anions mediated by Cs+ cations

The synthesis and crystal structure determination (at 293 K) of the title complex, Cs[Fe(C8H6BrN3OS)2], are reported. The compound is composed of two dianionic O,N,S-tridentate 5-bromo­salicyl­aldehyde thio­semicarbazonate(2-) ligands coord­inated to an FeIII cation, displaying a distorted octa­hedral geometry. The ligands are orientated in two perpendicular planes, with the O- and S-donor atoms in cis positions and the N-donor atoms in trans positions. The complex displays inter­molecular N-H...O and N-H...Br hydrogen bonds, creating R44(18) rings, which link the FeIII units in the a and b directions. The FeIII cation is in the low-spin state at 293 K

Ammonium bis(salicylaldehyde thiosemicarbazonato)ferrate(III), a supramolecular material containing low-spin FeIII

The synthesis and crystal structure (100 K) of the title com­pound, ammonium bis­[salicyl­aldehyde thio­semi­car­ba­zon­ato(2−)-κ3O,N1,S]iron(III), NH4[Fe(C8H7N3OS)2], is reported. The asymmetric unit consists of an octa­hedral [FeIII(thsa)2]− fragment, where thsa2− is salicyl­aldehyde thio­semi­car­ba­zon­ate(2−), and an NH4+ cation. Each thsa2− ligand binds via the thiol­ate S, the imine N and the phenolate O donor atoms, resulting in an FeIIIS2N2O2 chromophore. The ligands are orientated in two perpendicular planes, with the O and S atoms in cis and the N atoms in trans positions. The FeIII ion is in the low-spin state at 100 K. The crystal structure belongs to a category I order–disorder (OD) family. It is a polytype of a maximum degree of order (MDO). Fragments of the second MDO polytype lead to systematic twinning by pseudomerohedry

Structure of trans-bis[4-amino-3,5-bis(pyridin-2-yl)-1,2,4-triazole-N1,N'[diaqua- manganese(II) dibromide

[Mn(C12H10N6)2(H2O)2]Br2, Mr = 727.28, orthorhombic, Pbca, a = 10.734 (6), b = 17.084 (0), c = 15.182 (6) angstrom, V = 2784 angstrom 3, Z = 4, D(x) = 1.734 g cm-3, lambda-(Mo K-alpha) = 0.71073 angstrom, mu = 33.23 cm-1, F(000) = 1450, T = 295 K, final R = 0.032 for 1493 reflections [I > 2-sigma(I)]. The title compound is the first reported mononuclear compound with the ligand 4-amino-3,5-bis(pyridin-2-yl)-1,2,4-triazole. The manganese ions, situated on an inversion centre, are coordinated by four nitrogen atoms with an N-Mn-N angle of 74.1 (1)-degrees and Mn-N distances of 2.188 (4) and 2.266 (4) angstrom. Two axial water molecules [Mn-O = 2.200 (4) angstrom] complete the coordination sphere of the metal, which is pseudo-octahedral. The two bromide ions are not coordinated but are involved in an extended hydrogen-bridging network with the water ligands and the amino group of the triazole

Synthetic, Crystallographic, and Computational Study of Copper(II) Complexes of Ethylenediaminetetracarboxylate Ligands

Copper(II) complexes of hexadentate ethylenediaminetetracarboxylic acid type ligands H4eda3p and H4eddadp (H4eda3p = ethylenediamine-N-acetic-N,N′,N′-tri-3-propionic acid; H4eddadp = ethylenediamine-N,N′-diacetic-N,N′-di-3-propionic acid) have been prepared. An octahedral trans(O6) geometry (two propionate ligands coordinated in axial positions) has been established crystallographically for the Ba[Cu(eda3p)]·8H2O compound, while Ba[Cu(eddadp)]·8H2O is proposed to adopt a trans(O5) geometry (two axial acetates) on the basis of density functional theory calculations and comparisons of IR and UV−vis spectral data. Experimental and computed structural data correlating similar copper(II) chelate complexes have been used to better understand the isomerism and departure from regular octahedral geometry within the series. The in-plane O−Cu−N chelate angles show the smallest deviation from the ideal octahedral value of 90°, and hence the lowest strain, for the eddadp complex with two equatorial β-propionate rings. A linear dependence between tetragonality and the number of five-membered rings has been established. A natural bonding orbital analysis of the series of complexes is also presented.

A viscosity study of charcoal-based nanofluids towards enhanced oil recovery

Research into nanofluids for enhanced oil recovery (EOR) has been carried out for more than a decade. Metal oxide nanoparticles dispersed in water are usually applied and the nanofluids can recover 8–16 % more of the original oil in place after or comparing to water flooding, while the oil recovery capacity of carbon tube nanofluids can be even better. Higher viscosities of nanofluids than that of water are one of the key properties that contribute to their good performance in EOR. This work, for the first time, prepared nanofluids from two charcoal samples as well as an active carbon sample for their possible application for EOR. The relationship of nanofluid viscosities with pH values as well as nanoparticle concentrations of the nanofluids was studied for their viscous behaviour in different shear conditions. Their representative viscosity data measured at 100 rpm were examined for the values of the so-called Dispersion Factor (DF). The determined DF values for the charcoal-based nanofluids are close to those of metal oxide nanofluids that have much smaller nanoparticle sizes. The highly porous active carbon nanofluid showed strong viscosity enhancement that is comparable to the values reported for nanofluids of carbon nanotubes. Due to their significant viscosity enhancement and carbon sequestration feature, the charcoal-based nanofluids are promising to be used for EOR

Fe III in the high‐spin state in dimethylammonium bis[3‐ethoxysalicylaldehyde thiosemicarbazonato(2–)‐κ 3 O 2, N 1, S ]ferrate(III)

The synthesis and crystal structure (100 K) of the title compound, [(CH3)2NH2][Fe(C10H11O2N3S)2], are reported. The asymmetric unit consists of an octahedral [FeIII(L)2]− fragment, where L2− is 3‐ethoxysalicylaldehyde thiosemicarbazonate(2−), and a dimethylammonium cation. Each L2− ligand binds with the thiolate S, the imine N and the phenolate O atoms as donors, resulting in an FeIIIS2N2O2 chromophore. The ligands are orientated in two perpendicular planes, with the O and S atoms in cis positions, and mutually trans N atoms. The FeIII ion is in the high‐spin state at 100 K. The variable‐temperature magnetic susceptibility measurements (5–320 K) are consistent with the presence of a high‐spin FeIII ion with D = 0.83 (1) cm−1 and g = 2

Fe III in the high‐spin state in dimethylammonium bis[3‐ethoxysalicylaldehyde thiosemicarbazonato(2–)‐κ 3 O 2, N 1, S ]ferrate(III)

The synthesis and crystal structure (100 K) of the title compound, [(CH3)2NH2][Fe(C10H11O2N3S)2], are reported. The asymmetric unit consists of an octahedral [FeIII(L)2]− fragment, where L2− is 3‐ethoxysalicylaldehyde thiosemicarbazonate(2−), and a dimethylammonium cation. Each L2− ligand binds with the thiolate S, the imine N and the phenolate O atoms as donors, resulting in an FeIIIS2N2O2 chromophore. The ligands are orientated in two perpendicular planes, with the O and S atoms in cis positions, and mutually trans N atoms. The FeIII ion is in the high‐spin state at 100 K. The variable‐temperature magnetic susceptibility measurements (5–320 K) are consistent with the presence of a high‐spin FeIII ion with D = 0.83 (1) cm−1 and g = 2