Synthesis of (3-(2-thiazolin-2-yl)thiazolidine-2-thione) (triphenylphosphine)-copper(I) bromide with a new coordination core of Cu(I)

<div><p>The thio-ligand, 3-(2-thiazolin-2-yl)thiazolidine-2-thione (<i>L</i>^<i>2</i>, C₃H₄S₂N-C₃H₄SN), generated <i>in situ</i> from the reaction of thiazolidine-2-thione (L¹, NC₃H₅S₂) with copper(I) bromide in CH₃CN under aerobic conditions involved C–S bond cleavage and yielded a three coordinate complex, (3-(2-thiazolin-2-yl)thiazolidine-2-thione)copper(I) bromide <b>1</b>. Treatment of <b>1</b> with PPh₃ in MeOH/CH₂Cl₂ mixture formed a copper(I) complex, (3-(2-thiazolin-2-yl)thiazolidine-2-thione)(triphenylphosphine)copper(I) bromide <b>2</b>. This complex has four different types of donor atoms bonded to Cu(I) forming a central core,{Cu(N,P,S,Br)}, which is very unusual as normally the cores of known tetrahedral complexes are of type, {Cu(P₂,S,X)}(X = halogen).</p><p>Complex (3-(2-thiazolin-2-yl)thiazolidine-2-thione)(triphenylphosphine)copper(I) bromide <b>2</b> has unusual coordination core, Cu(N,P, S, Br).</p></div

Solid State Analysis and Theoretical Explorations on Polymorphic and Hydrate Forms of p-Hydroxybenzaldehyde Isonicotinichydrazone: Effect of Additives on Polymorphic Crystallization

The reaction of p-hydroxybenzaldehyde with an equimolar amount of isonicotinic hydrazide afforded two polymorphic and hydrate forms of p-hydroxybenzaldehyde isonicotinichydrazone (HBIH) by varying the experimental reaction conditions. The compounds are fully characterized by means of single crystal and powder diffraction methods, vibrational spectroscopy (FT-IR and Raman), thermal and elemental analysis. The compound crystallizes in three different forms in two different space groups, P21/c (form PA and PB) and Pbca (PC). The Hirshfeld surface analysis shows the differences in the relative contributions of intermolecular interactions to the total Hirshfeld surface area for the HBIH molecules. The calculated pairwise interaction energies (104-116 kJ/mol) can be related to the stability of the crystals. Energy framework analysis identifies the interaction hierarchy and their topology. The geometry and conformation of the three forms are essentially similar which differ only by packing arrangement

Unusual coordination of mononuclear cobalt(III) complexes with sterically demanding Schiff bases: synthesis, spectroscopy, electrochemistry, crystallography, DNA binding, and theoretical investigation

<p>Three mononuclear Co^III complexes, [Co(L^{1 <i>t</i>Bu})(bdbp)]·2EtOH (<b>1</b>), [Co(L^{2 <i>t</i>Bu})(bdbp)] (<b>2</b>), and [Co(L^{3 <i>t</i>Bu})₂]ClO₄ (<b>3</b>) (where H₂L^{1 <i>t</i>Bu} = bis[{6-benzoyl-4-<i>tert</i>-butyl-2-hydroxyphenyl}benzi-midoyl]-1,2-ethane, H₂L^{2 <i>t</i>Bu} = bis[{6-benzoyl-4-<i>tert</i>-butyl-2-hydroxyphenyl}benzimidoyl]-1,3-propane, bdbpH = 4-<i>tert</i>-butyl-2,6-dibenzoylphenol and HL^{3 <i>t</i>Bu} = 2-{N-(4-amino-butyl)benzimidoyl}-6-benzoyl-4-<i>tert</i>-butylphenol), have been synthesized by one-pot condensation involving Co^II perchlorate, ethane-1,2-diamine, propane-1,3-diamine, and butane-1,4-diamine. The Schiff bases, H₂L² and HL³, and <b>1–3</b> have been characterized by elemental analyses, conductivity measurements, mass spectrometry, IR, electronic, ¹H and ¹³C NMR spectroscopy, cyclic voltammetry, and X-ray crystallography. In <b>1</b> and <b>2</b>, the tetradentate ONNO ligand wraps around cobalt in a rare <i>β cis</i>-conformation. Complex <b>3</b> possesses a tridentate NNO ligand leading to two seven-membered chelate rings in a <i>fac</i>-CoN₄O₂ octahedral configuration. Density functional theory (DFT) calculations provide a satisfactory description of the electronic properties of the new compounds. All the complexes are redox active and display the Co(III)–Co(II) couple in the potential range −0.6– + 0.3 V (<i>vs</i>. Ag/AgNO₃). Interaction of the complexes with calf thymus DNA (CT-DNA) has been investigated by a spectrophotometric method and cyclic voltammetry. Based on these observations, an intercalative binding mode of DNA has been proposed. The order of their intrinsic DNA binding constants <i>K</i>_b is <i>K</i>_b (<b>1</b>) < <i>K</i>_b (<b>2</b>) < <i>K</i>_b (<b>3</b>). The observed trend in the binding constant values is consistent with the energy gap between the HOMO and LUMO molecular orbitals.</p

One-Pot Synthesis of Polycyclic Spirooxindoles via Montmorillonite K10-Catalyzed C–H Functionalization of Cyclic Amines

A method for pot and atom economic synthesis of polycyclic spirooxindoles through α-C–H functionalization of cyclic amines has been developed. This highly efficient three-component [3+2] cycloaddition reaction was catalyzed by recyclable montmorillonite K10 and only water was produced as a byproduct

Organocatalytic One-Pot Asymmetric Synthesis of Thiolated Spiro-γ-lactam Oxindoles Bearing Three Stereocenters

The first asymmetric synthesis of spiro-γ-lactam oxindoles bearing three stereocenters is reported. One-pot thiol-Michael/Mannich/lactamization reactions promoted by a recyclable fluorous bifunctional cinchona alkaloid/thiourea organocatalyst afford products in moderate to good yields with up to 95% ee and 6:1 dr

Organocatalytic One-Pot Asymmetric Synthesis of Thiolated Spiro-γ-lactam Oxindoles Bearing Three Stereocenters

The first asymmetric synthesis of spiro-γ-lactam oxindoles bearing three stereocenters is reported. One-pot thiol-Michael/Mannich/lactamization reactions promoted by a recyclable fluorous bifunctional cinchona alkaloid/thiourea organocatalyst afford products in moderate to good yields with up to 95% ee and 6:1 dr

Synthesis and Properties of the Strained Alkene Perfluorobicyclo[2.2.0]hex-1(4)-ene

The title fluoroalkene has been generated by dehalogenation of dibromide and diiodide precursors and trapped <i>in situ</i>. <i>retro</i>-Diels–Alder reaction of its adduct with <i>N</i>-benzylpyrrole has made the alkene available in high yield and purity. In sharp contrast to its extremely labile hydrocarbon counterpart, the fluoroalkene is very stable yet highly reactive. Its characterization includes its electron affinity, photoelectron spectrum, and the previously reported structure determination by electron diffraction

Synthesis and Properties of the Strained Alkene Perfluorobicyclo[2.2.0]hex-1(4)-ene

The title fluoroalkene has been generated by dehalogenation of dibromide and diiodide precursors and trapped <i>in situ</i>. <i>retro</i>-Diels–Alder reaction of its adduct with <i>N</i>-benzylpyrrole has made the alkene available in high yield and purity. In sharp contrast to its extremely labile hydrocarbon counterpart, the fluoroalkene is very stable yet highly reactive. Its characterization includes its electron affinity, photoelectron spectrum, and the previously reported structure determination by electron diffraction

Synthesis, characterization, and computational study of three-coordinate SNS-copper(I) complexes based on bis-thione precursors

<div><p>A series of tridentate pincer ligands, each possessing two sulfur and one nitrogen donor (SNS), based on bis-imidazolyl or bis-triazolyl salts were metallated with CuCl₂ to give new tridentate SNS pincer copper(I) complexes [(SNS)Cu]⁺. These orange complexes exhibit a three-coordinate pseudo-trigonal-planar geometry in copper. During the formation of these copper(I) complexes, disproportionation is observed as the copper(II) salt precursor is converted into the Cu(I) [(SNS)Cu]⁺ cation and the [CuCl₄]^2– counteranion. The [(SNS)Cu]⁺ complexes were characterized with single crystal X-ray diffraction, electrospray mass spectrometry, EPR spectroscopy, attenuated total reflectance infrared spectroscopy, UV–Vis spectroscopy, cyclic voltammetry, and elemental analysis. The EPR spectra are consistent with anisotropic Cu(II) signals with four hyperfine splittings in the lower-field region (<i>g</i>_||) and <i>g</i> values consistent with the presence of the tetrachlorocuprate. Various electronic transitions are apparent in the UV–Vis spectra of the complexes and originate in the copper-containing cations and anions. Density functional calculations support the nature of the SNS binding, allowing assignment of a number of features present in the UV–Vis and IR spectra and cyclic voltammograms of these complexes.</p></div