Organotin(IV) complexes derived from proteinogenic amino acid: synthesis, structure and evaluation of larvicidal efficacy onAnopheles stephensimosquito larvae

Engineered organotin(IV) and vanadium(V) derivatives with distinct coordination modes and luminescent properties for the efficient detection and quantification of permanganate ions

The distinction in coordination modes of metal complexes leads to their versatile structural features and unique properties. Here, we report two tetradentate Schiff base ligands (H₂L¹ and H₂L²) bearing N₂O₂ donor sets, tactically selected to provide distinct coordination modes with different metal ions. The ligands were utilized to synthesize their organotin(IV) (1-4) and vanadium(V) (5) derivatives. The synthesized compounds were characterized using elemental analysis, FT-IR spectroscopy, multi-nuclei NMR (¹H, ¹³C, and ¹¹⁹Sn) spectroscopy, mass spectrometry, and single-crystal X-ray diffraction. The organotin(IV) derivatives (1-4) displayed hepta-coordination around both the Sn centres as they were achieved in their dimeric form. Contrariwise, the vanadium(V) compound (5) was isolated as a mononuclear entity exhibiting penta-coordinated geometry around the vanadium centre. The variation in the coordination modes was evident in their UV-vis and fluorescence spectra. The organotin(IV) compounds (1-4) exhibited a strong emission band centred at 468 nm when excited at a wavelength of 360 nm whereas the vanadium(V) (5) derivative displayed poor fluorogenic response. Compound 1 was further explored for the fluorogenic chemo-sensing of permanganate ions (MnO₄^-) amongst various anions by quenching response. A detailed investigation of the recognition of permanganate ions was accomplished by spectrofluorometric, spectroscopic (¹¹⁹Sn NMR), mass spectrometric, and computational studies.

Structural diversity among some dialkyltin(IV) benzoate and related derivatives

The molecular structures of five diorganotin(IV) carboxylates, (I)-(V), can be categorized into two main well-known structural types for such Sn complexes. One is the mononuclear dialkytin(IV) carboxylates with an [R₂Sn(LH)₂]-type skew-trapezoidal bipyramid, where the alkyl ligands are in pseudo-axial positions and the O atoms from two asymmetrically coordinated bidentate carboxylate ligands are in the equatorial plane. This structure type is adopted by dibutylbis{(E)-2-hydroxy-5-[(3-methylphenyl)diazenyl]benzoato}tin(IV) cyclohexane hemisolvate, [Sn(C₄H₉)₂(C₁₄H₁₁N₂O₃)₂]·0.5C₆H₁₂, (I), dibenzylbis{(E)-5-[(4-bromophenyl)diazenyl]-2-hydroxybenzoato}tin(IV), [Sn(C₇H₇)₂(C₁₃H₈BrN₂O₃)₂], (II), and aquadibenzylbis(4-{(E)-[(Z)-4-hydroxypent-3-en-2-ylidene]amino}benzoato)tin(IV) benzene disolvate, [Sn(C₇H₇)₂(C₁₂H₁₂NO₃)₂(H₂O)]·2C₆H₆, (III), although the latter has an additional water ligand to give a distorted pentagonal bipyramidal coordination geometry in which the carboxylate groups are more symmetrically coordinated to the Sn atom than in (I) and (II). The other structure motif is that of the tetranuclear bis(dicarboxylatotetraorganodistannoxanes), {[R₂Sn(LH)]₂O}₂, which contain an Sn₄O₂ core decorated with four bridging carboxylate ligands, plus two alkyl ligands at each Sn^IV centre. The complexes octabutyltetrakis{μ-(E)-4-[(4-hydroxy-3,5-dimethylphenyl)diazenyl]benzoato}di-μ₃-oxido-tetratin(IV) ethanol disolvate, [Sn₄(C₄H₉)₈(C₁₅H₁₃N₂O₃)₄O₂]·2C₂H₆O, (IV), and octabutyltetrakis{(E)-3-[(2-hydroxybenzylidene)amino]propanoato}di-μ₃-oxido-tetratin(IV), [Sn₄(C₄H₉)₈(C₁₀H₁₀NO₃)₄O₂], (V), display this motif. The structures obtained correlate with the 1:1 and 1:2 stoichiometric ratios of the dialkyltin(IV) and carboxylic acid starting materials in the syntheses. The supramolecular structures arising from consideration of secondary Sn...O interactions and/or classic hydrogen bonds include discrete molecules for (V), centrosymmetric dimers for (I), extended chains for (II) and (III), and sheets for (IV).

Investigating the structural chemistry of organotin(IV) compounds: recent advances

Organotin(IV) compounds have been considered for their outstanding industrial, medical and specific applications in the synthesis of various types of chemical compounds. In this review, we have focused on the structural chemistry of organotin(IV) compounds, including coordination chemistry, the effect of structure on reactions, bond formations from the perspective of structure and investigation of the structure of organotin(IV) compounds in different phases. The structural chemistry of organotin(IV) compounds is subject to interest due to their major impact on predicting the properties and drumming up support for pushing back the frontiers of synthesis of organotin(IV) compounds with advanced properties.

Exploration of fluorescent organotin compounds of α-amino acid Schiff bases for the detection of organophosphorous chemical warfare agents: quantification of diethylchlorophosphate

Fluorescent Schiff base organotin probes for the detection of chemical warfare agents.