A novel proton transfer supramolecular compound induced by N–H⋯O hydrogen bond through 18-crown-6: Syntheses,structures, and dielectric properties

A novel organic–inorganic hybrid supramolecular compound, [(4-Nitroanilinium)(18-crown-6)][BF₄](CH₃CN), was prepared via H-bond dipole interactions between 4-nitroanilinium, 18-crown-6, and BF₄⁻, in acetonitrile solution. N–H…O hydrogen bonds between neighboring 4-nitroanilinium cations and 18-crown-6 were observed. However, the formation of one-dimensional supramolecular chain structure via N–H…O that contacts through the cavity of 18-crown-6 was worth noting. A strong dielectric response was observed above 300 K at a low frequency of 500 Hz, thereby suggesting the proton transfer in the N–H…O bonds.     

Syntheses and Structural Characterization of Triorganotin Derivatives of Bis(carboxymethyl)trithiocarbonate: X-ray Crystal Structures of 2D Network Polymers

Six triorganotin(IV) complexes of the type {(R₃Sn)₂[C₃S₃(COO)₂]}_n (R = C₆H₅ 1; n-Bu 2; PhCH₂ 4; p-F-PhCH₂ 5; o-F-PhCH₂ 6) and {(R₃Sn)₂[C₃S₃(COO)₂]}_n·[EtOH] (R = Me 3) have been synthesized by the reaction of bis(carboxymethyl)trithiocarbonate with triorganotin(IV) chloride in the presence of sodium ethoxide. All complexes were characterized by elemental analysis IR, ¹H, ¹³C and ¹¹⁹Sn NMR spectroscopy. Except for 4–6, all complexes were also characterized by X-ray crystallography. The X-ray date revealed that complexes 1–3 show two-dimensional network polymeric structure in which the geometries of tin atoms are trigonal bipyramid with the axial positions occupied by carboxylic oxygen atoms.     

Synthesis and Structures of Two Triorganotin(IV) Polymers R3Sn{O2CC6H4[N=C(H)}{C(CH3)CH(CH3)-3-OH]-p} n (R = Me and Ph) Containing a 4-[(2Z)-(3-Hydroxy-1-methyl-2-butenylidene)amino] benzoic Acid Framework

Two new polymeric triorganotin(IV) complexes R₃Sn{O₂CC₆H₄[N=C(H)}{C(CH₃)CH(CH₃)-3-OH]-p} _n ([Me₃Sn(LH)] _n : 1) and ([Ph₃Sn(LH)] _n : 2) containing a 4-[(2Z)-(3-hydroxy-1-methyl-2-butenylidene)amino]benzoate (LH) framework were prepared. Both compounds have been characterized by ¹H, ¹³C, ¹¹⁹Sn NMR, IR and ¹¹⁹Sn Mössbauer spectroscopic techniques in combination with elemental analyses. The crystal structures of complexes 1 and 2 reveal that they exist as polymeric zig-zag chains in which the LH-bridged Sn-atoms adopt a trans-R₃SnO₂ trigonal bipyramidal configuration with R groups in the equatorial positions and the axial sites occupied by an oxygen atom from the carboxylate ligand and the alcoholic oxygen atom of the next carboxylate ligand in the chain. The carboxylate ligands coordinate in the zwitterionic form with the alcoholic proton moved to the nearby nitrogen atom.     

Synthesis, Characterization and In vitro Antitumour Activity of Novel Organotin Derivatives of 1,2- and 1,7-Dicarba-Closo-dodecaboranes

Several organotin derivatives of 1,2- and 1,7-dicarba-closo-dodecaboranes were synthesized and characterized by ¹¹⁹Sn Mössbauer, ¹H, ¹³C and ¹¹⁹Sn NMR spectroscopy. Their antitumour activities in vitro against cancerous cell lines of human origin are reported.     

Spectral Studies and Bactericidal, Fungicidal, Insecticidal and Parasitological Activities of Organotin(IV) Complexes of Thio Schiff Bases Having no Donor Atoms

Twelve new organotin(IV) complexes of the type RnSnLm [where n = 3, m = 1, R = CH₃ or C₆H₅; n = 2, m = 2, R = C₆H₅ or C₄H₉ ; L = anion of Schiff bases derived from the condensation of 2-amino-5-(o-anisyl)-l,3,4-thiadiazole with salicylaldehyde (HL-1), 2- hydroxynaphthaldehyde (HL-2) and 2-hydroxyacetophenone (HL-3)] have been synthesized and characterized by elemental analysis, molar conductances, electronic, infrared, far-infrared, ¹H NMR and ¹¹⁹Sn Mössbauer spectral studies. Thermal studies of two complexes, viz., Ph₃Sn (L-1) and Ph₂Sn(L-2)₂ have been carried out in the temperature range 25-1000∘C using TG, DTG and DTA techniques. All these complexes decompose gradually with the formation of SnO₂ as an end product. In vitro antimicrobial activity of the Schiff bases and their complexes has also been determined against Streptococcus faecalis, Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus Penicillin resistance (2500 units), Candida albicans, Cryptococcus neoformans, Sporotrichum schenckii, Trichophyton mentagrophytes and Aspergillus fumigatus. The Schiff bases (HL-1), (HL-2) and the organotin(IV) compounds have also been tested against various important herbicidal, fungicidal, insecticidal species and also for parasitological activity against freeliving nematode.     

Synthesis and Structure Characterization of Some Triorganotin Esters of Heteroaromatic Carboxylic Acid and Crystal Structure of Triphenyltin Esters of 6-Hydroxynicotinic Acid and 5-Chloro-6-hydroxynicotinic Acid

Reactions of (R₃Sn)₂O (R=Ph, 2-ClC₆H₄CH₂, 2-FC₆H₄CH₂, 4-CNC₆H₄CH₂) with 6-hydroxynicotinic acid and 5-chloro-6-hydroxynicotinic acid in 1:2 stoichiometry yielded eight triorganotin compounds. These compounds have been characterized by elemental analysis, IR and ¹H NMR spectroscopy. The crystal structures of triphenyltin esters of 6-hydroxynicotinic acid (1) and 5-chloro-6-hydroxynicotinic acid (2) were determined by single crystal X-ray diffraction. In these two compounds the tin atoms are rendered five-coordinate in a trigonal bipyramidal structure by coordination though the three phenyl carbon atoms and two oxygen atoms, one from carboxylate and other from the phenolic hydroxide. The resulting structures are two one-dimensional linear polymers through an interaction between the O atoms of phenolic hydroxide and tin atoms of an adjacent molecule.     

Cyanide binding to iron in a highly distorted porphyrin macrocycle: Synthesis and structure of low-spin Fe(II) dicyano porphyrin

Dark brown crystals of [K(18-crown-6)(H₂O)₂]₂[Fe^II(tn-OEP)(CN)₂] are grown by slow diffusion of cyclohexane into the THF solutions of the molecule generated via auto reduction of [Fe^III(tn-OEP)Cl] in the presence of KCN and 18-crown-6 at room temperature in air and structurally characterized. The complex represents the first structurally characterized dicyano Fe(II) porphyrins in a highly distorted and sterically crowded macocyclic environment. The metal iron is on the plane of the four porphyrinic nitrogens which are accompanied by the decrease of the saddle distortion with a clear and significant increase in ruffling.     

Synthesis of Triorganostannate Esters of Dicarboxylic Acids: X-ray Crystal Structure of Polymeric Triethylammonium 2,5-Thiophenedicarboxylatotriphenylstannate

The triethylammonium 2,5-thiophenedicarboxylatotriorganostannates, [(C₂H₅)₃ NH]-[R₃Sn((O₂C)₂C₄H₂S)] (R = Me (1), n-Bu (2), Ph (3), PhCH₂ (4)), have been prepared from triethylamine, 2,5-thiophenedicarboxylic acid and triorganotin chloride. All the compounds, 1–4, have been characterized by elemental, IR and ¹H-NMR analyses. An X-ray analysis of the R = phenyl compound shows that the structure is polymeric with neighboring triorganotin centers being linked by dicarboxylate ligands. Each carboxylate moiety is involved in coordination to a Sn atom via one O atom only showing that the Sn atoms are five-coordinate and exist in trigonal bipyramidal geometries. Moreover, the ammonium nitrogen is hydrogen bonded to the carbonyl oxygen.     

Synthesis, Characterization and Thermogravimetric Analysis of Two Dicyclohexyl-18-crown-6 Pd, Pt Isomaleonitriledithiolate Complexes

Two organic–inorganic hybrid dicyclohexyl-18-crown-6 complexes, [K(DC18C6-B)]₂[Pd(i-mnt)₂] (1) and [K(DC18C6-A)]₂[Pt(i-mnt)₂] (2) (DC18C6-A=cis-syn-cis-dicyclohexyl-18-crown-6, A isomer; DC18C6-B = cis-anti-cis-dicyclohexyl-18-crown-6, B isomer; i-mnt=1,1-dicyanoethene-2,2-dithiolate, isomaleonitriledithiolate), were synthesized by the reaction of dicyclohexyl-18-crown-6 with K₂(i-mnt) and PdCl₂ or K₂PtCl₄ respectively. These were characterized by elemental analysis, FT–IR, UV–Vis spectroscopy and single crystal X-ray diffraction. In complex 1, two [K(DC18C6-B)]⁺ complex cations and one [Pd(i-mnt)₂]²⁻ complex anion formed a neutral molecule through two K–N coordination bonds. The resulting molecule adopted a 1D chain arrangement via K N weak interactions. Complex 2 showed a 1D chain-like structure that was assembled by two [K(DC18C6-A)]⁺ complex cations and one [Pt(i-mnt)₂]²⁻ complex anion through N–K–N interactions. An erratum to this article can be found at     

Synthesis and Structural Characterization of Triorganotin(IV) Derivatives with 2,2′-Thiodiglycolic Acid and 3,3′-Thiodipropionic Acid

The synthesis and structural characterization of four novel triorganotin(IV) complexes, {(R₃Sn)₂[C₂H₄S(COO)₂]} _n (R = Me: 1), {(R₃Sn)₄[C₂H₄S(COO)₂]₂} _n (R = nBu: 2), {(R₃Sn)₂[C₄H₈S(COO)₂]} _n (R = Me: 3; nBu: 4) were obtained by the reaction of 2,2′-thiodiglycolic acid, 3,3′-thiodipropionic acid and the corresponding R₃SnCl (R = Me, nBu) with potassium hydroxide in methanol. All the complexes were characterized by elemental analysis, Fourier transform infrared and nuclear magnetic resonance (¹H, ¹³C, ¹¹⁹Sn) spectroscopies, X-ray crystallography and thermogravimetric analyses. The crystal structures show that 1 has 2D network structure in which 2,2′-thiodiglycolic acid acts as a tetradentate ligand coordinating to the trimethyltin(IV) ions. Complexes 2, 3, and 4 are 3D metal-organic framework structures in which the deprotoned acids act as a tetradentate ligand afforded by four oxygen atoms.     

Specific membrane transport of silver and copper as Ag(CN)3 and Cu(CN)4 ions through a supported liquid membrane using K-crown ether as a carrier

Facilitated transport of silver and copper from cyanide solutions through a supported liquid membrane (SLM) containing K⁺-crown ether as a carrier is described. The SLM used is a thin porous polypropylene (Celgard 2500, 2400) membrane impregnated with dibenzo-18-crown-6 (DB18C6), diaza-18-crown-6 (DA18C6), hexathia-18- crown-6 (HT18C6) and hexaaza-18-crown-6 (HA18C6) dissolved in a mixture of ethanol/chloroform (v/v). K₋⁺-crown ether showed a high efficiency to carry silver and copper as Ag(CN)₃²⁻ and Cu(CN)₄³⁻ species through the SLM. However, the mass flux of both silver and copper ions decreases when concentration of cyanide ions in the feed phase increases due to the difference in stability of the complexes M(CN)_nⁿ⁻(M=Ag, Cu) when n increases from 2 to 4. This was related to the partition of the species in the aqueous phase using a theoretical model.     

Synthesis, characterization and biological activity of dimethyltin dicarboxylates containing germanium

A series of diorganotin dicarboxylates of the general formula (CH₃)₂Sn(OCOCHR³CHR²GeR¹)₂ where R¹=(C₆H₅)₃, (P-CH₃C₆H₄)3, N(CH₂CH₂O)₃, R²=C₆H₅, H, CH₃, P-CH₃OC₆H₄, P-ClC₆H₄, P-CH₃C₆H₄, R³=CH₃ and H, have been synthesized by the reaction of dimethyltin oxide with germanium substituted propionic acid in 1:2 molar ratio in toluene. The H₂O formed was removed azeotropically using a Dean and Stark apparatus. All the compounds have been characterized by IR, multinuclear (¹H, ¹³C, ¹¹⁹Sn) NMR, mass and Mössbauer spectroscopies. All compounds were found to have potential activity against bacteria.     

The synthesis,using microwave irradiation and characterization of novel,organosoluble metal-free and metallophthalocyanines substituted with flexible crown ether moieties

Cyclotetramerization of a phthalonitrile derivative to the metal-free phthalocyanine was accomplished in n-pentanol in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene at reflux under an argon atmosphere. Ni(II), Zn(II), Co(II), Cu(II) phthalocyanines with four, peripheral 4-[methyleneoxy(12-crown-4)] groups were synthesized from 4-[{(12-crown-4)-yl}methyleneoxy]phthalonitrile in the presence of the anhydrous, divalent metal salts (NiCl₂, Zn(CH₃COO)₂, CoCl₂ and CuCl₂). The green phthalocyanines were soluble in common organic solvents such as CHCl₃, CH₂Cl₂, CH₃COCH₃, THF, DMF and DMSO. The structures of the target compounds were confirmed using elemental analysis, IR, ¹H NMR, ¹³C NMR, UV–vis and MS spectral data.     

Nanoparticle formulation of poly(?-caprolactone-co-lactide)-d-α-tocopheryl polyethylene glycol 1000 succinate random copolymer for cervical cancer treatment

Cervical cancer remains a critical problem that is second only to breast cancer affecting women worldwide. The objective of this study was to develop formulation of docetaxel-loaded biodegradable poly(?-caprolactone-co-lactide)-d-α-tocopheryl polyethylene glycol 1000 succinate (PCL-PLA-TPGS) nanoparticles for cervical cancer chemotherapy. A novel random copolymer, PCL-PLA-TPGS, was synthesized from ?-caprolactone, lactide and d-a-tocopheryl polyethylene glycol 1000 succinate (TPGS) by ring-opening polymerization. The obtained polymers were characterized by ¹H NMR, FTIR, GPC and TGA. The docetaxel-loaded PCL-PLA-TPGS nanoparticles were prepared by a modified solvent extraction/evaporation technique and characterized in terms of size and size distribution, morphology, surface charge and physical state of encapsulated docetaxel. Cellular uptake and in vitro cytotoxicity of nanoparticle formulations were done in comparison with commercial formulation Taxotere^® to investigate the efficacy of PCL-PLA-TPGS nanoparticles. In vitro cellular uptakes of such nanoparticles were investigated with CLSM, demonstrating the coumarin 6-loaded PCL-PLA-TPGS nanoparticles could be internalized by Hela cells. In vitro cancer cell viability experiment showed that judged by IC₅₀, the PCL-PLA-TPGS nanoparticle formulation was found to be more effective in cell number reduction than the Taxotere^® after 48 h (p < 0.05), 72 h (p < 0.05) treatment. In conclusion, the PCL-PLA-TPGS copolymer could be acted as a novel and promising biologically active polymeric matrix material for nanoparticle formulation in cervical cancer treatment.     

The Synthesis and Characterization of Triorganotin Carboxylates of 2-Mercapto-4-methyl-5-thiazoleacetic Acid: X-ray Crystal Structures of Polymeric Me3Sn[O2CCH2(C4H3NS)S]SnMe3 and Ph3Sn[O2CCH2(C4H3NS)S]SnPh3

The triorganotin carboxylates of 2-mercapto-4-methyl-5-thiazoleacetic acid (1), R₃Sn[O₂CCH₂- (C₄H₃NS)S]SnR₃ (R=Me 2, n-Bu 3, Ph 4 PhCH₂ 5), have been synthesized and characterized by IR, ¹H and ¹³C NMR spectroscopy. Among them, complexes 2 and 4 were also characterized by X-ray crystallography diffraction analysis, which revealed that both 2 and 4 showed a one-dimensional polymeric structure in which the geometries of the tin atoms are different: one was a distorted tetrahedron and the other was trigonal bipyramidal with the axial positions occupied by oxygen atoms.     

Self-assembly syntheses and crystal structures of triphenyltin(IV) phenylphosphate: A 1D polymer and a dimer of 24-membered macrocycle

Two novel organotin(IV) complexes of the types [(Ph₃Sn)₄(O₃POPh)₂]_n 1 and [(Ph₃Sn)₆(O₃POPh)₃]₂ 2 have been prepared by treatment of phenylphosphoric acid and the Ph₃SnCl under different conditions. The complexes 1 and 2 were characterized by elemental analysis, IR and NMR (¹H,¹³C,¹¹⁹Sn) spectroscopy and X-ray crystallography diffraction analysis. The structure analyses reveal that complex 1 is an infinite 1D polymer and complex 2 is a dimer which contains two 24-membered macrocycles.     

Anticancer Potency Studies of Coordination Driven Self‐Assembled Arene–Ru‐Based Metalla‐Bowls

New tetranuclear cationic metalla‐bowls 5 – 7 with the general formula [Ru₄(p‐cymene)₄(N∩N)₂(OO∩OO)₂]⁴⁺ (N∩N=2,6‐bis(N‐(4‐pyridyl carbamoyl)pyridine, OO∩OO=2,5‐dihydroxy‐1,4‐benzoquinonato ( 5 ), OO∩OO=5,8‐dioxydo‐1,4‐naphthaquinonato ( 6 ), OO∩OO=hoxonato ( 7 )) were prepared by the reaction of the respective dinuclear ruthenium complexes 2 – 4 with a bispyridine amide donor ligand 1 in methanol in the presence of AgO₃SCF₃.These new molecular metalla‐bowls were fully characterized by analytical techniques including elemental analysis as well as ¹H and ¹³C NMR and HR‐ESI‐MS spectroscopy. The structure of metalla‐bowl 6 was determined from X‐ray crystal diffraction data. A UV/visible study was also carried out for the entire suite of new complexes. As with recent studies of similar arene–Ru complexes, the inhibition of cell growth by metalla‐bowls was established against SK‐hep‐1 (liver cancer), AGS (gastric cancer), and HCT‐15 (colorectal cancer) human cancer cell lines. Inhibition of cell growth by 6 was found to be considerably stronger against all cancer cell lines than the anticancer drugs, doxorubicin and cisplatin. In particular, in colorectal cancer cells, expression of the cancer suppressor genes APC and p53 was increased following exposure to 6 .     

Influence of guests and protonation on the conformation of N,N′-dipyridyl-bis-aza-18-crown-6

Crystallisation of the sodium perchlorate adduct of N,N^′-dipyridyl-bis-aza-18-crown-6 from acidic aqueous conditions yielded [(H₃O)(N,N^′-dipyridyl-bis-aza-18-crown-6)][ClO₄] and [Na·N,N^′-dipyridyl-bis-aza-18-crown-6]₂ [(H⁺)₂N,N^′-dipyridyl-bis-aza-18-crown-6][ClO₄]₄·2H₂O. The conformations of crown ethers were significantly influenced by incorporation of an H₃O⁺ or sodium ion, or protonation of the amino nitrogen atoms resulting in three different structures for the macrocycle.     

Syntheses and Characterization of 1D, 2D and 3D Organotin Polymers with Benzimidazole-5,6-dicarboxylic Acid and Trimethyltin Chloride

Three types of di- and trimethyltin(IV) polymers [Me₂Sn(C₉H₄N₂O₄)]_n · 4H₂O 1, [(Me₃Sn)₂(C₉H₄N₂O₄)]_n · H₂O 2 and [(Me₃Sn)₂(C₉H₄N₂O₄)]_n · CH₃OH 3 have been synthesized by the reaction of trimethyltin chloride with benzimidazole-5,6-dicarboxylic acid under three different experimental conditions. All the complexes were characterized by elemental analysis, IR, NMR (¹H, ¹³C, ¹¹⁹Sn) spectroscopy and X-ray crystallography diffraction analysis. The structure analyses reveal that complex 1 has a 1D helical chain in which benzimidazole-5,6-dicarboxylic acid act as a tetradentate (O,O-chelation) ligand coordinating to dimethyltin (IV) ions, two water molecules take part in the coordination giving seven-coordinated tin centers in the component. Complex 2 and 3 are 2D and 3D corrugated polymers in which the deprotoned acid as tetradentate ligand affords by three oxygen atoms and a nitrogen atom.     

Syntheses and Characterization of 2D and 3D Organotin Polymers with Phenylsuccinic Acid and Trimethyltin Chloride Under Different Conditions

Two types of di- and trimethyltin(IV) polymers [(Me₂Sn)₄O₂(C₁₀H₈O₄)₄] _n 1 and [(Me₃Sn)₂(C₁₀H₈O₄)] _n ·DMF 2 have been synthesized by the reaction of trimethyltin chloride with (±)-phenylsuccinic acid under two different experimental conditions. Both of the complexes are characterized by elemental analysis, IR, NMR (¹H, ¹³C, ¹¹⁹Sn) spectroscopy and X-ray crystallographic diffraction analysis. The structural analyses show that complex 1 is a two-dimensional corrugated sheet polymer consisting of dimeric tetraorganodistannoxane units and bridging ligands. Complex 2 is a 3D corrugated polymer in which the deprotoned acid occurs as a tetradentate ligand and is bonded by the four oxygen atoms. It is worth noting that the X-ray diffraction study reveals that complex 2 crystallizes in the orthorhombic space group P212121, which is chiral space group.