(2Z,3Z)-3,4-Dihydro-2H-1,4-benzothia­zine-2,3-dione dioxime dihydrate

In the mol­ecule of the title compound, C8H11N3O4S, the thia­zine ring adopts an envelope conformation. In the crystal structure, inter­molecular N—H⋯O, O—H⋯O and O—H⋯N hydrogen bonds link the mol­ecules

(2Z,3Z)-Quinoxaline-2,3(1H,4H)-dione dioxime

The asymmetric unit of the title compound, C8H8N4O2, contains one half-mol­ecule; a twofold rotation axis bisects the molecule. An intra­molecular N—H⋯O hydrogen bond results in the formation of a five-membered ring, which displays an envelope conformation. In the crystal structure, inter­molecular O—H⋯N hydrogen bonds link the mol­ecules

N-(2-Thienylmethyl­ene)-2-(2-{[2-(2-thienylmethyl­eneamino)phen­yl]sulfan­yl}ethyl­sulfan­yl)aniline

The asymmetric unit of the title compound, C24H20N2S4, contains one half-mol­ecule: a crystallographic centre of inversion is located at the mid-point of the two central C atoms. The thio­phene ring is oriented at a dihedral angle of 60.64 (3)° with respect to the benzene ring. In the crystal structure, π–π contacts between thio­phene rings [centroid–centroid distance = 3.581 (1) Å] may stabilize the structure. A weak C—H⋯π inter­action is also present

Synthesis, characterization and thermodynamic studies of complexes of dimethyl, diethyl, and diphenyltin(IV) dichlorides with (2H)-1,4-benzothiazine-2,3-(4H)-dione dioxime

The diorganotin(IV) compounds, [Me2SnCl2(H2L)], [Et2SnCl2(H2L)] and [Ph2SnCl2(H2L)] (H2L = (2H)-1,4-benzothiazine-2,3-(4H)-dione dioxime), were synthesized by treating the appropriate diorganotin(IV) dichloride with H2L in anhydrous ethanol. These complexes were characterized by IR, MS, UV-Vis, and 1H NMR. Thermodynamic studies of the reported complexes have been carried out and their stability were found in the order: [Me2SnCl2(H2L)] > [Et2SnCl2(H2L)] > [Ph2SnCl2(H2L)]. Theoretical calculations at the HF/3-21G* level showed that structures with alkyl groups at axial positions are more stable than their counterparts having alkyl groups at equatorial. KEY WORDS: Diorganotin(IV) dichloride, vic-Dioxime, (2H)-1,4-Benzothiazine-2,3-(4H)-dionedioxime, Thermodynamic studies Bull. Chem. Soc. Ethiop. 2012, 26(1), 85-94.DOI: http://dx.doi.org/10.4314/bcse.v26i1.

<b>Comparison of acceptor properties for interaction of TCNE and DDQ with some free base porphyrins</b>

The interactions of free base porphyrins with tetracyanoethylene and 2,3-dichloro-5,6-dicyanobezoquinone as acceptors result in charge-transfer adducts of composition 2:1 of acceptor to donor, [(acceptor)2 (donor)]. Formation constants, K, as well as the thermodynamic parameters, ΔHº, ΔSº, and ΔGº were determined by UV-Vis titration method for the adducts. Surprisingly, the values of ΔSº &rsaquo; 0 and ΔHº &rsaquo; 0 for TCNE are in contrast to ΔHº &rsaquo; 0 and ΔSº &rsaquo; 0 for DDQ. Negative values of ΔGº make these interactions favorable in the both cases

Theoretical Study of Mixed Hydrogen and Dihydrogen Bond Interactions in BH 4 (NH 3 ) n − Clusters

Ab initio calculations were used to analyze interactions of BH 4 − with 1-4 molecules of NH 3 at the MP2/6-311++G(d,p) and the B3LYP/6-311++G(d,p) computational levels. In addition to H 3 B-H⋅ ⋅ ⋅ H-NH 2 dihydrogen bond, the H 2 N-H⋅ ⋅ ⋅ NH 3 hydrogen bonds were also predicted in clusters. Negative cooperativity in clusters constructed from mixed H 3 B-H⋅ ⋅ ⋅ H-NH 2 dihydrogen and H 2 N-H⋅ ⋅ ⋅ NH 3 hydrogen bonds are more remarkable. The negative cooperativity increases with size and number of hydrogen bonds in cluster. The B-H stretching frequencies show blue shifts with respect to cluster formation. Greater blue shift in stretching frequencies was predicted for B-H bonds which did not contribute to dihydrogen bonding with NH 3 molecules. The structures were analyzed with the atoms in molecules (AIM) methodology

Aluminum-Selective Electrode Based on (1E,2E)-N1,N2- dihydroxy )-N1,N2- bis (4-hydroxy phenyl) Oxalimidamide as a Neutral Carrier

A synthesized,(1E,2E)-N1, N2- dihydroxy-N1, N2-bis (4-hydroxyphenyl) oxalimidamide (DBO) , has been used as an ionophore in order to preparation of a new ion-selective electrode. An optimized membrane was prepared by mixing of 70 mg PVC powdered, 2 mg of considered ionophore, 100 mg of plasticizer and 2 mg of additive. The sensor exhibits reversible potential responses with an almost Nernstian slope for Al3+ ions in the concentration range from 1.0 ´ 10-6 M to 1.30´10-1 M. The limit of detection (LOD) was 2.50 ´ 10-7 M The electrode’s response is independent of pH in the range of 3.2-7.8. The response time of the electrode is about 15 s and can be used for 50 days without any divergence in potential. The practical application of the electrode was tested by using it as indicator electrode to determine the end point in the potentiometric titration of Al3+ with EDTA solution