Exploring the reactivity of L-tellurocystine, Te-protected tellurocysteine conjugates and diorganodiselenides towards hydrogen peroxide: synthesis and molecular structure analysis

The synthesis of a series of novel organotellurium species and diorganoselenones is reported.

Crystal structure, Hirshfeld surface analysis and DFT study of 2,2''-({[(1E,1'E)-(diselanedi-yl)bis-(2,1-phenyl-ene)]bis-(methane-ylyl-idene)}bis-(aza-neylyl-idene))bis-[3',6'-bis-(di-ethyl-amino)-4a',9a'-di-hydro-spiro-[isoindoline-1,9'-xanthen]-3-one]

The title compound, C₇₀H₇₀N₈O₄Se₂, is a spiro bicyclic diselenide, made up of two [SeC₆H₄CH=N-N(CO)C₆H₄(C)C₆H₃NEt₂(O)C₆H₃NEt₂] units related by a twofold crystallographic symmetry element bis-ecting the diselenide bond. The compound crystallizes in a non-centrosymmetric polar space group (tetra-gonal, P b2) and the structure was refined as an inversion twin. The two diethyl amine groups and their attached phenyl groups of the xanthene ring are disordered over two orientations, with occupancies of 0.664 (19)/0.336 (19) and 0.665 (11)/0.335 (11), respectively. The dihedral angles between the mean planes of the central isoindoline and the phenyl rings are 26.8 (2) and 2.5 (4)°, respectively. The mean plane of the central xanthene ring forms dihedral angles of 2.0 (5), 8.8 (5), 1.7 (5) and 7.9 (6)° with the peripheral phenyl rings. The isoindoline and xanthene rings subtend a dihedral angle of 89.8 (2)°. The mol-ecular conformation is stabilized by an intra-molecular C-H⋯O hydrogen bond generating an S(6) ring motif. In the crystal, mol-ecules are linked by C-H⋯O hydrogen bonds together with C-H⋯π (ring) inter-actions, forming a three-dimensional network. A Hirshfeld surface analysis of the crystal structure indicates that the most important contributions to the crystal packing are from H⋯H (68.1%), C⋯H/H⋯C (21.2%) and O⋯H/H⋯O (8.7%) contacts. The optimized structure calculated using density functional theory (DFT) at the B3LYP/6 - 31 G(d) level is compared with the experimentally determined mol-ecular structure in the solid state. The HOMO-LUMO behaviour was used to determine the energy gap and the mol-ecular electrostatic potential (MEP) of the compound was investigated.

A luminescent terbium(iii) probe as an efficient ‘Turn-ON’ sensor for dipicolinic acid, a Bacillus Anthracis biomarker

This work drives the potential of lanthanide luminescence in the quantification and detection of the B. Anthracis bacterial spore by targeting dipicolinic acid (DPA), a principal component of anthrax spores.

Metal complexes of a pro-vitamin K3 analog phthiocol (2-hydroxy-3-methylnaphthalene-1,4-dione): synthesis, characterization, and anticancer activity

Anticancer activity of geometrical isomers of phthiocol complexes are evaluated against MCF-7 and A549 cell lines.

N, Kumara K, Lokanath NK, Butcher RJ, Kumbar V, Bhat K. Copper(i) complexes with quinolone appended 1,8-naphthalimide conjugates: structural characterization, DNA and protein binding and cytotoxicity studies

Cytotoxicity, cellular uptake of copper(i) complexes containing 1,8-naphthalimide conjugates have been investigated.

M, Patra M, Butcher RJ, Manjare ST. Selective detection of hypochlorous acid in living cervical cancer cells with an organoselenium-based BOPPY probe

The synthesis and crystal structure of the first selenium-containing BOPPY probe. The probe is selective for exogenous and endogenous HOCl detection in HeLa cells with a “turn-on” fluorescence response.

Crystal structures of 3/4-pyridyl-based thiosemicarbazones and related Cu and Ni coordination compounds

In this investigation, the crystal structures of the thio-ligands 3-formylpyridine 4-phenylthiosemicarbazone (C₁₃H₁₂N₄S, 1) and 4-benzoylpyridine 4-ethylthiosemicarbazone (C₁₅H₁₆N₄S, 2), and of two new coordination compounds, chlorido(3-formylpyridine 4-phenylthiosemicarbazone-κS)bis(triphenylphosphane-κP)copper(I) acetonitrile monosolvate, [CuCl(C₁₃H₁₂N₄S)(C₁₈H₁₅P)₂]·CH₃CN, 3, and bis(3-formylpyridine 4-ethylthiosemicarbazonato-κ²N¹,S)nickel(II), [Ni(C₉H₁₁N₄S)₂], 4, are reported. In complex 3, the thio-ligand coordinates in a neutral form to the Cu atom through its S-donor atom, and in complex 4, the anionic thio-ligand chelates to the Ni atom through N- and S-donor atoms. The geometry of complex 3 is distorted tetrahedral [bond angles 99.70 (5)-123.23 (5)°], with the P-Cu-P bond angle being the largest, while that of complex 4 is square planar, with trans-S-Ni-S and N-Ni-N bond angles of 180°.

The structures of 1:1 and 1:2 adducts of phosphane-tricarbo-nitrile with 1,4-di-aza-bicyclo[2.2.2]octa-ne

In the structures of 1:1 and 1:2 adducts of phosphanetricarbo-nitrile (C3N3P) with 1,4-di-aza-bicyclo-[2.2.2]octane (C6H12N2), the 1:1 adduct crystallizes in the ortho-rhom-bic space group, Pbcm, with four formula units in the unit cell (Z' = 0.5). The P(CN)3 unit lies on a crystallographic mirror plane while the C6H12N2 unit lies on a crystallographic twofold axis passing through one of the C-C bonds. The P(CN)3 moiety has close to C 3v symmetry and is stabilized by forming adducts with two symmetry-related C6H12N2 units. The phospho-rus atom is in a five-coordinate environment. As a result of the symmetry, the two trans angles are equal so τ5 = 0.00 and thus the geometrical description could be considered to be square pyramidal. However, the electronic geometry is distorted octa-hedral with the lone pair on the phospho-rous occupying the sixth position. As would be expected from VSEPR considerations, the repulsion of the lone-pair electrons with the equatorial bonding electrons means that the trans angles for the latter are considerably reduced from 180° to 162.01 (4)°, so the best description of the overall geometry for phospho-rus is distorted square pyramidal. The 1:2 adduct crystallizes in the monoclinic space group, P21/m with two formula units in the asymmetric unit (i.e. Z' = 1/2). The P(CN)3 moiety lies on a mirror plane and one of the two C6H12N2 (dabco) mol-ecules also lies on a mirror plane. The symmetry of the P(CN)3 unit is close to C 3v. There are three P⋯N inter-actions and consequently the mol-ecular geometry of the phospho-rus atom is distorted octa-hedral. This must mean that the lone pair of electrons on the phospho-rus atom is not sterically active. For the 1:1 adduct, there are weak associations between the phospho-rus atom and one of the terminal nitro-gen atoms from the C≡ N moiety, forming chains in the a-axis direction. In addition there are weak C-H⋯N inter-actions between a terminal nitro-gen atoms from the C≡N moiety and the C6H12N2 mol-ecules, which form sheets perpendicular to the a axis.

Tetramethylammonium (Z)-N′-cyanocarbamimidate

In the structure of the tetramethyl ammonium salt of cyanourea, C4H12N+·C2H2N3O−, the N—C and O—C bond distances in the cyano and keto groups are in the normal range for such a moieties at 1.1641 (18) and 1.2550 (16) Å. However, the bonds about the central C and N atoms are much shorter than would be expected for single bonds and indicate that there is considerable electron delocalization in the anion as was also found in the silver salt. The NH2 group is coplanar with the central N2CO core, in contrast with the nitrile group where the dihedral angle between the N—C—N and N2CO planes is 36.5 (3)°. The packing of the cations and anions in the unit cell involves N—H...O hydrogen bonds between anions characterized by an R 2 2(8) motif, as well as N—H...O hydrogen bonds between anions and C—H...O interactions between both cations and anions, forming an R 3 3(14) pattern.

Antiproliferative activity and electrochemical oxygen evolution by Ni(II) complexes of N'-(aroyl)-hydrazine carbodithioates

The electrochemical water splitting by transition metal complexes is emerging very rapidly. The nickel complexes also play a very vital role in various biological activities. Here, three new ligands {H₂mbhce = N'-(4-methyl-benzoyl), H₂pchce = N'-(pyridine-carbonyl) and H₂hbhce = N'-(2-hydroxy-benzoyl) hydrazine carbodithioic acid ethyl ester} and their corresponding Ni(II) complexes [Ni(Hmbhce)₂(py)₂] (1), [Ni(pchce)(o-phen)₂]·CH₃OH·H₂O (2) and [Ni(hbhce)(o-phen)₂]·1.75CHCl₃·H₂O (3) have been synthesized and fully characterized by various physicochemical and X-ray crystallography techniques. The photoluminescence study and thermal degradations were also examined. The treatment of K562 cells with the increasing concentrations of the nickel salts, ligands, and complexes 1, 2, and 3 showed dose-dependent cytotoxicity. The cytotoxic activity of ligands reveals that ligand H₂mbhce is more potent in inhibiting the growth of tumor cells in comparison to other ligands H₂pbhce and H₂hbhce. Cytotoxicity assay results indicate that all complexes have remarkable cytotoxic potential in comparison to either nickel salts or the free ligands. Among these complexes, complex 1 has significantly better anti-tumor activity as compared to complexes 2 and 3. The electrochemical study of complexes 1, 2, and 3 for water oxidation reveals that all the complexes possess admirable electrocatalytic activity towards oxygen evolution reaction (OER) and have lower overpotential (328, 338, and 370 mV, respectively) than many previously reported complexes and RuO₂ (390 mV). Among complexes 1, 2, and 3, complex-2 shows a better water oxidation response. Consequently, these complexes have great potential to be utilized in fuel cells. The more reliable electrochemical parameter TOF is also calculated for all three complexes.

Dual sensing of methionine and aspartic acid in aqueous medium by a quinoline-based fluorescent probe

A quinoline-based Schiff base sensor, 6-methyl-2-oxo-1,2-dihydro-quinoline-3-carboxaldehyde-4(N)-phenylsemicarbazone (6MPS), has been developed for selective sensing of methionine and aspartic acid in aqueous medium through "on-off-on" type selective detection of copper ion. Fluorescence imaging of 6MPS, 6MPSC, 6MPSCN, 6MPSC-met, 6MPSCN-met, 6MPSC-asp and 6MPSCN-asp has been successfully demonstrated, in which the sensing probes 6MPSC-met, 6MPSCN-met, 6MPSC-asp and 6MPSCN-asp displayed bright green fluorescence in both in vitro and in vivo live cells.

Tetra-kis[μ2-1,1,1,3,3,3-hexa-fluoro-2-(tri-fluoro-meth-yl)propan-2-olato]tetra-kis-(μ3-2-methyl-propan-2-olato)octa-copper(I)

The structure of the title ocyacopper cluster contains two C₁₆H₁₈Cu₄F₁₈O₄ units linked through a center of inversion by weak Cu—O bonds.

The title compound, [Cu₈(C₄H₉O)₄(C₄F₉O)₄], crystallizes in the monoclinic space group, P2₁/n and contains a self-assembly of two C₁₆H₁₈Cu₄F₁₈O₄ units linked by bridging tert-butyl groups [Cu—O bonds of length 2.3779 (15) and 2.4248 (15) Å], generating a centrosymmetric dimer. The asymmetrical unit, C₁₆H₁₈Cu₄F₁₈O₄, contains an almost square-planar arrangement of the four Cu atoms linked by bridging tert-butyl and perfluorinated tert-butyl groups with Cu—Cu distances ranging from 2.7108 (4) to 2.7612 (4) Å and Cu —Cu—Cu angle values close to 90° [ranging from 89.459 (10)° to 90.025 (11)°]. These dimers are further linked by weak C—H⋯F and F⋯F inter­actions. As is commonly encountered in perfluorinated tert-butyl groups, one of the CF₃ groups is disordered and was refined with two equivalent conformations with occupancies of 0.74 (3) and 0.26 (3).

μ-Methyl-ene-bis-[di-bromido(diethyl ether-κO)aluminium(III)]: crystal structure and chemical exchange in solution

The crystal structure of μ-methyl­ene-bis­[(di­bromo)(diethyl ether-κO)aluminium(III)] has established that the Al—CH₂—Al angle, 118.4 (2)°, is the smallest observed for structure where this moiety is not part of a ring.

In the title compound, [Al₂Br₄(CH₂)(C₄H₁₀O)₂], the mol­ecule lies on a crystallographic twofold axis passing through the bridging C atom. Each Al^III atom is four-coordinate, being bonded to two bromide ions, bridging the CH₂ group as well as the oxygen atom of a diethyl ether ligand in a slightly distorted tetra­hedral arrangement with angles ranging from 101.52 (8) to 116.44 (5)°. The Al—CH₂—Al angle, 118.4 (2)°, is the smallest observed for a structure where this moiety is not part of a ring. In the crystal, weak C—H⋯Br inter­actions, characterized as R²₂(12) rings, link the mol­ecules into ribbons in the [101] direction. The title compound is monomeric and coordinatively saturated in the solid state, as each aluminum is four-coordinate, but in solution the ether mol­ecules from either or both Al atoms can dissociate, and would be expected to rapidly exchange, and this is supported by NMR data.

Bis(2-nitrophenyl) selenide, bis(2-aminophenyl) selenide and bis(2-aminophenyl) telluride: structural and theoretical analysis

Three organoselenium and organotellurium compounds containing ortho substitutents, namely, bis(2-nitrophenyl) selenide, C₁₂H₈N₂O₄Se, 2, bis(2-aminophenyl) selenide, C₁₂H₁₂N₂Se, 3, and bis(2-aminophenyl) telluride, C₁₂H₁₂N₂Te, 7, have been investigated by both structural and theoretical methods. In the structures of all three compounds, there are intramolecular contacts between both Se and Te with the ortho substituents. In the case of 2, this is achieved by rotation of the nitro group from the arene plane. For 3, both amino groups exhibit pyramidal geometry and are involved in intramolecular N-H...Se interactions, with one also participating in intermolecular N-H...N hydrogen bonding. While 3 and 7 are structurally similar, there are some significant differences. In addition to both intramolecular N-H...Te interactions and intermolecular N-H...N hydrogen bonding, 7 also exhibits intramolecular N-H...N hydrogen bonding. In the packing of these molecules, for 2, there are weak intermolecular C-H...O contacts and these, along with the O...N interactions mentioned above, link the molecules into a three-dimensional array. For 3, in addition to the N-H...N and N-H...Se interactions, there are also weak intermolecular C-H...Se interactions, which also link the molecules into a three-dimensional array. On the other hand, 7 shows intermolecular N-H...N interactions linking the molecules into R₂²(16) centrosymmetric dimers. In the theoretical studies, for compound 2, AIM (atoms in molecules) analysis revealed critical points in the Se...O interactions with values of 0.017 and 0.026 a.u. These values are suggestive of weak interactions present between Se and O atoms. For 3 and 7, the molecular structures displayed intramolecular, as well as intermolecular, hydrogen-bond interactions of the N-H...N type. The strength of this hydrogen-bond interaction was calculated by AIM analysis. Here, the intermolecular (N-H...N) hydrogen bond is stronger than the intramolecular hydrogen bond. This was confirmed by the electron densities for 3 and 7 [ρ_(r) = 0.015 and 0.011, respectively].

Ethyl 2-amino-4-methylthiophene-3-carboxylate

The title compound crystallizes with two mol­ecules, A and B, in the asymmetric unit. Each molecule features an intramolecular N—H⋯O hydrogen bond and the same H atom is also involved in an intermolecular N—H⋯S bond to generate A + B dimers. Further N—H⋯O hydrogen bonds link the dimers into a [010] chain.

The title compound, C₈H₁₁NO₂S, crystallizes with two mol­ecules, A and B, in the asymmetric unit. Each molecule features an intramolecular N—H⋯O hydrogen bond and the same H atom is also involved in an intermolecular N—H⋯S bond to generate A + B dimers. Further N—H⋯O hydrogen bonds link the dimers into a [010] chain.

Structural and theoretical studies of 4-chloro-2-methyl-6-oxo-3,6-dideuteropyrimidin-1-ium chloride (d 6)

The title compound, C5D6ClN2O+·Cl-, crystallizes in the ortho-rhom-bic space group, Pbcm, and consists of a 4-chloro-2-methyl-6-oxo-3,6-di-hydro-pyrimidin-1-ium cation and a chloride anion where both moieties lie on a crystallographic mirror. The cation is disordered and was refined as two equivalent forms with occupancies of 0.750 (4)/0.250 (4), while the chloride anion is triply disordered with occupancies of 0.774 (12), 0.12 (2), and 0.11 (2). Unusually, the bond angles around the C=O unit range from 127.2 (6) to 115.2 (3)° and similar angles have been found in other structures containing a 6-oxo-3,6-di-hydro-pyrimidin-1-ium cation, including the monclinic polymorph of the title compound, which crystallizes in the monoclinic space group P21/c [Kawai et al. (1973 ▸). Cryst. Struct. Comm. 2, 663-666]. The cations and anions pack into sheets in the ab plane linked by N-H⋯Cl hydrogen bonds as well as C-H⋯O and Cl⋯O inter-actions. In graph-set notation, these form R 3 3(11) and R 3 2(9) rings. Theoretical calculations seem to indicate that the reason for the unusual angles at the sp 2 C is the electrostatic inter-action between the oxygen atom and the adjacent N-H hydrogen.

Syntheses and structures of two benzoyl amides: 2-chloro-4-eth-oxy-3,5-dimeth-oxy-N-(3-oxo-cyclo-hex-1-en-1-yl)benzamide and 2-chloro-N-(5,5-dimethyl-3-oxo-cyclo-hex-1-en-1-yl)-4-eth-oxy-3,5-di-meth-oxy-benzamide

The first title benzoyl amide, C₁₇H₂₀ClNO₅ (3a), crystallizes in the monoclinic space group P2₁/c with Z = 4 and the second, C₁₉H₂₄ClNO₅ (3b), also crystallizes in P2₁/c with Z = 8 (Z' = 2), thus there are two independent mol-ecules in the asymmetric unit. In 3a, the phenyl ring makes a dihedral angle of 50.8 (3)° with the amide moiety with the C=O group on the same side of the mol-ecule as the C-Cl group. One meth-oxy group is almost in the plane of the benzene ring, while the eth-oxy and other meth-oxy substituent are arranged on opposite sides of the ring with the eth-oxy group occupying the same side of the ring as the C=O group in the amide moiety. For one of the two mol-ecules in 3b, both the amide and 5,5-dimethyl-3-oxo-cyclo-hex-1-en-1-yl moieties are disordered over two sets of sites with occupancies of 0.551 (2)/0.449 (2) with the major difference between the two conformers being due to the conformation adopted by the cyclo-hex-2-en-1-one ring. The three mol-ecules in 3b (i.e., the undisordered mol-ecule and the two disorder components) differ in the arrangement of the subsituents on the phenyl ring and the conformation adopted by their 5,5-dimethyl-3-oxo-cyclo-hex-1-en-1-yl moieties. In the crystal of 3a, N-H⋯O hydrogen bonds link the mol-ecules into a zigzag chain propagating in the [001] direction. For 3b a combination of C-H⋯O and N-H⋯O inter-molecular inter-actions link the mol-ecules into a zigzag ribbon propagating in the [001] direction.

A trinuclear nickel(II) Schiff base complex with phenoxido- and acetato-bridges: combined experimental and theoretical magneto-structural correlation

We describe the synthesis and characterization of a new trinuclear Ni(ii) Schiff base complex of formula [Ni3(L)2(NCS)2(OAc)2(CH3OH)2] (1) where HL is the 1 : 1 condensation product of 2-picolylamine and o-vanillin. The crystal structure of complex 1 shows that the two terminal Ni(ii) ions are connected to the central one through a phenoxido- and a syn-syn acetato bridge, giving rise to a very bent configuration in the Ni3-core. Magnetic susceptibility measurements show the presence of a weak antiferromagnetic coupling with J = -3.22(2) cm-1. We also report a magneto-structural correlation, performed with all the magnetically characterized Ni(ii) trimers with similar bridges, showing a linear dependence between the J value and the dihedral angle (θ) between the planes containing the Ni-O-Ni and the carboxylate bridges. The super-exchange interaction is investigated by extensive density functional calculations within the broken symmetry approximation which show good agreement with the experimental data. The analysis of the spin density distribution and the shape of the magnetically active single occupied molecular orbitals (SOMO) provide a mechanism of exchange coupling through the bridging groups.

The crystal structure of the deca-aluminum alkoxide cluster Al10O4(OH)8 L 14 (L = 1,1,1,3,3,3-hexa-fluoro-propan-2-olate)

The title centrosymmetric deca­aluminum cluster, Al₁₀O₄(OH)₈(C₃HF₆O)₁₄, contains two OAl₄ units and a central Al₂(O)₂ bridge.

In the title centrosymmetric cluster compound, hexa­kis­(μ₂-1,1,1,3,3,3-hexa­fluoro­propan-2-olato)octa­kis­(1,1,1,3,3,3-hexa­fluoro­propan-2-olato)octa-μ₂-hydroxido-di-μ₄-oxido-di-μ₃-oxido-deca­aluminium, [Al₁₀(C₃HF₆O)₁₄(OH)₈O₄] (C₄₂H₂₂Al₁₀F₈₄O₂₆), there is a central μ₄-OAl₄ moiety, which has six edges of which three contain μ(O)-1,1,1,3,3,3-hexa­fluoro­propan-2-olate (L) ligands and two contain μ-OH groups each bridging two Al atoms along an edge. The sixth edge is occupied by a group containing a fifth aluminium atom [bis-μ(OH)-, μ₃(O)—AlL]. This last μ₃(O) group generates a centrosymmetric Al₂O₂ dimer, thus the μ₃(O) atom is linked to two Al atoms in the asymmetric unit as well as a third Al atom through a center of inversion. Three of the hexa­fluoro­propyl groups of the C₃HF₆O⁻ ligands are disordered and each was refined with two conformations with occupancies of 0.770 (3)/0.230 (3), 0.772 (3)/0.228 (3) and 0.775 (3)/0.225 (3). The five unique Al centers have coordination numbers varying from four to six with bond angles that show considerable distortions from regular geometry: for the four-coordinate atom, τ₄′ = 0.886, while three Al atoms are five-coordinate (τ₅ values = 0.098, 1.028, and 0.338) and one is distorted six-coordinate with O—Al—O bond angles ranging from 74.22 (9) to 171.59 (12)°. The geometry about the central O atom in the OAl₄ block is significantly distorted tetra­hedral (τ₄′ = 0.630) with Al—O—Al angles ranging from 95.50 (9) to 147.74 (13)°. The extended structure features numerous O—H⋯O, O—H⋯F, C—H⋯O and C—H⋯F hydrogen bonds and short F⋯F contacts.

Synthesis, structure, and theoretical studies of a calcium complex of a unique dianion derived from 1-methyl-pyrrolidin-2-one

The title compound, catena-poly[[tetra-kis-(1-methyl-pyrrolidin-2-one-κO)calcium(II)]-μ-(E)-1,1'-dimethyl-2,2'-dioxo-1,1',2,2'-tetra-hydro-[3,3'-bipyrrolyl-idene]-5,5'-bis-(thiol-ato)-κ2 O:O'], [Ca(C10H8N2O2S2)(C5H9NO)4] n , 1, crystallizes in the triclinic space group P . The crystal studied was twinned by non-merohedry via two different twofold operations, about the normals to (001) and (10), giving four twin domains with refined occupancies of 0.412 (4), 0.366 (4), 0.055 (1), 0.167 (4). The Ca atoms are located on centers of inversion. Each Ca is surrounded by four 1-methyl-pyrrolidin-2-one (NMP) ligands and coordinated through one of the two O atoms to two (E)-1,1'-dimethyl-2,2'-dioxo-1,1',2,2'-tetra-hydro-[3,3'-bipyrrolyl-idene]-5,5'-bis-(thiol-ate), [C10H8N2O2S2]2-, dianions (abbreviation: DMTBT). This dianion thus facilitates the formation of a 1-D polymer, which propagates in the [011] direction. These ribbons are linked by inter-molecular C-H⋯S inter-actions. Each Ca atom is in an octa-hedral CaO6 six-coordinate environment with Ca-O bond lengths ranging from 2.308 (6) to 2.341 (6) Å, cis bond angles ranging from 88.2 (2) to 91.8 (2)° and the trans angles all 180° due to the Ca atoms being located on centers of inversion. Theoretical calculations were carried out using density functional theory (DFT) and the results showed that although the central DMTBT dianion is planar there is likely some resonance across the central bond between both aza-pentyl rings, but this is not sufficient to establish a ring current. The calculated UV-vis spectrum shows a peak at 625 nm, which accounts for the deep blue-purple color of solutions of the complex.

Catalytic and highly regenerable aminic organoselenium antioxidants with cytoprotective effects

N-Methyl ebselenamines carrying an aminic group in very close proximity to selenium as excellent chain-breaking and glutathione peroxidase-like antioxidants could reduce the production of ROS in C6 astroglial cell lines with minimal toxic effects.

Structure of a diorganotelluroxonium(IV) cation, {[2,6-(CH2NMe2)2C6H3Te(μ-O)]2}2+, with the tri-chlorido-(dimethyl sulfoxide)-platinum(II) anion

In the title salt, di-μ-oxido-bis-{2,6-bis-[(di-methyl-amino)-meth-yl]phenyl-κC ¹}tellurium(-IV) bis[tri-chlorido-(dimethyl sulfoxide-κS)platinate(II)], (C₂₄H₃₈N₄O₂Te₂)[PdCl₃(C₂H₆OS)]₂, which crystallizes in the triclinic space group P , each Te atom is in a distorted five-coordinated TeO₂N₂C square-pyramidal geometry (τ values of 0.026 and 0.001) with the C atoms of the phenyl rings occupying the apical positions. The phenyl rings in the [C₂₄H₃₈N₄O₂Te₂]²⁺ cation are in a cis arrangement to enable this species to participate in Te⋯Cl cation-anion inter-actions. There are also C-H⋯O inter-actions involving the dimethyl sulfoxide ligands and numerous cation-anion and anion-anion C-H⋯Cl inter-actions, which link the ions into a complex three-dimensional array.

(Z)-N′-[(E)-4-Methoxybenzylidene]-2-(methoxyimino)-2-{2-[(2-methylphenoxy)methyl]phenyl}acetohydrazide

The title compound crystallizes with two mol­ecules in the asymmetric unit. In the crystal, asymmetric, bifurcated N—H⋯(N,O) hydrogen bonds link the mol­ecules into [100] chains. The packing is consolidated by weak C—H⋯O inter­actions.

The title compound, C₂₅H₂₅N₃O₄, crystallizes with two mol­ecules in the asymmetric unit. In both mol­ecules, the central ethane hydrazide moiety is almost planar. In the crystal, asymmetric, bifurcated N—H⋯(N,O) hydrogen bonds link the mol­ecules into [100] chains. The packing is consolidated by weak C—H⋯O inter­actions.

Structural characterization of the derivatives of bis{[2,6-(dimethylamino)methyl]phenyl} selenide with palladium(II) and mercury(II)

The intramolecularly coordinated homoleptic diorgano selenide bis{2,6-bis[(dimethylamino)methyl]phenyl} selenide, C₂₄H₃₈N₄Se or R₂Se, where R is 2,6-(Me₂NCH₂)₂C₆H₃, 14, was synthesized and its ligation reactions with Pd^II and Hg^II precursors were explored. The reaction of 14 with SO₂Cl₂ and K₂PdCl₄ resulted in the formation of the meta C-H-activated dipalladated complex {μ-2,2'-bis[(dimethylamino)methyl]-4,4'-bis[(dimethylazaniumyl)methyl]-3,3'-selanediyldiphenyl-κ⁴C¹,N²:C^1',N^2'}bis[dichloridopalladium(II)], [Pd₂Cl₄(C₂₄H₃₈N₄Se)] or [{R(H)PdCl₂}₂Se], 15. On the other hand, when ligand 14 was reacted with HgCl₂, the reaction afforded a dimercurated selenolate complex, {μ-bis{2,6-bis[(dimethylamino)methyl]benzeneselanolato-κ⁴N²,Se:Se,N⁶}-μ-chlorido-bis[chloridomercury(II)], [Hg₂(C₁₂H₁₉N₂Se)Cl₃] or RSeHg₂Cl₃, 16, where two Hg^II ions are bridged by selenolate and chloride ligands. In palladium complex 15, there are two molecules located on crystallographic twofold axes and within each molecule the Pd moieties are related by symmetry, but there are still two independent Pd centers. Mercury complex 16 results from the cleavage of one of the Se-C bonds to form a bifurcated SeHg₂ moiety with the formal charge on the Se atom being -1. In addition, one of the Cl ligands bridges the two Hg atoms and there are two terminal Hg-Cl bonds. Each Hg atom is in a distorted environment which can be best described as a T-shaped base with the bridging Cl atom in an apical position, with several angles close to 90° and with one angle much larger and closer to 180°.

Adaptable DNA-Interactive Probe Proficient at Selective Turn-On Sensing for Al3+: Insight from the Crystal Structure, Photophysical Studies, and Molecular Logic Gate

The synthesized Schiff base ligand 3-hydroxy-N'-(2-hydroxy-3-methoxybenzylidene)-2-naphthohydrazide (H₂NPV) is structurally characterized by single-crystal X-ray diffraction (XRD) and exhibits weak fluorescence in the excited state owing to the effect of excited-state-induced proton transfer (ESIPT). However, in the presence of Al³⁺, the ESIPT is blocked and chelation-enhanced fluorescence (CHEF) is induced because of complexation with the cations, resulting in turn-on emission for Al³⁺. The probe H₂NPV selectively detects Al³⁺ among the various metal ions, and the detection limit is found to be 1.70 μM. The composition and modes of complex coordination were determined by spectroscopic, theoretical studies and molecular logic gate applications. Finally, DNA binding studies were performed by spectroscopic and calorimetric methods to elucidate possible bioactivity of H₂NPV.

Adaptable DNA-Interactive Probe Proficient at Selective Turn-On Sensing for Al3+: Insight from the Crystal Structure, Photophysical Studies, and Molecular Logic Gate

The synthesized Schiff base ligand 3-hydroxy-N'-(2-hydroxy-3-methoxybenzylidene)-2-naphthohydrazide (H2NPV) is structurally characterized by single-crystal X-ray diffraction (XRD) and exhibits weak fluorescence in the excited state owing to the effect of excited-state-induced proton transfer (ESIPT). However, in the presence of Al3+, the ESIPT is blocked and chelation-enhanced fluorescence (CHEF) is induced because of complexation with the cations, resulting in turn-on emission for Al3+. The probe H2NPV selectively detects Al3+ among the various metal ions, and the detection limit is found to be 1.70 μM. The composition and modes of complex coordination were determined by spectroscopic, theoretical studies and molecular logic gate applications. Finally, DNA binding studies were performed by spectroscopic and calorimetric methods to elucidate possible bioactivity of H2NPV.

Isolation of the novel example of a monomeric organotellurinic acid

The synthesis of the first example of a monomeric, stable organotellurinic acid is reported by utilizing the σ-hole participation of the Te atom with the N atom of the 2-(2′-pyridyl)phenyl moiety.

Influence of anion induced geometry change in Zn(ii) on the magnetization relaxation dynamics of Dy(iii) in Zn–Dy–Zn complexes

A series of [Zn₂Dy(L₁)₂(OAc)₄](X) where X = (NO₃)_0.92(Br)_0.08 (1), ClO₄ (2), Cl (3) and PF₆ (4) complexes were synthesized and their dc and ac magnetic data investigated. Experimental results are validated through MOLCAS calculations.

Metallophilic interactions: observations of the shortest metallophilicinteractions between closed shell (d10⋯d10, d10⋯d8, d8⋯d8) metal ions [M⋯M′ M = Hg(ii) and Pd(ii) and M′ = Cu(i), Ag(i), Au(i), and Pd(ii)]

The salt metathesis reaction of two equivalents of 8-lithioquinoline (C₆H₆NLi) with HgBr₂ afforded bis(quinoline-8-yl)mercury, [(C₆H₆N)₂Hg].

New 1,2,3-triazole based bis- and trisphosphine ligands: synthesis, transition metal chemistry and catalytic studies

This paper describes a novel synthetic methodology for the preparation of 1,2,3-triazole based phosphines and their transition metal chemistry and preliminary catalytic studies.

Design and synthesis of a sulphur containing Schiff base drug: DNA binding studies and theoretical calculations

The Schiff base compound MTA ((E)-5-methyl-N'-((5-methylthiophen-2-yl)methylene)-1H-pyrazole-3-carbohydrazide) derived from 2-thiophenecarboxaldehyde and 5-methylpyrazole-3-carbohydrazide has been designed to develop new sulphur containing DNA targeted molecule. The MTA has been characterized by elemental analyses, ¹H-NMR, single crystal X-ray diffraction studies as well as by geometry optimization of using DFT/B3LYP. The interaction of MTA with Calf thymus DNA (CT-DNA) was studied by spectroscopic and calorimetric techniques. The synthesized compound was found to bind with CT-DNA through groove binding mode, and the binding constant was estimated to be (4.15 ± 0.08) × 10⁴ M^-1. The negative ΔG⁰ and positive ΔS⁰ values obtained from the calorimetric technique confirmed the spontaneity of the binding of MTA with DNA.Communicated by Ramaswamy H. Sarma.