Synthesis, structure, and complexing ability of hetarylhydrazones of glyoxylic acid

Benzoxazolyl-, benzthiazolyl-, 2′-quinolinyl- and 1′-phthalazinylhydrazones of glyoxylic acid (H₂L) and their complexes have been synthesized. The acid-base properties of the obtained hydrazones were studied by the methods of potentiometric titration and spectrophotometry. The hydrazones were shown to form mononuclear octahedral complexes M(HL)₂ with Ni(II) and Mn(II) acetates, whereas with Zn(II) and Cu(II) acetates binuclear complexes M₂L₂ were formed. The nature of the exchange interaction between the Cu(II) ions is discussed.     

Phosphorylated macrocycles: structures,complexing properties,and molecular recognition

Procedures were developed for functionalization of macrocycles by introducing a phosphonic group either directly linked to the aromatic rings (in the case of cyclophanes or calixarenes) or as a pendant arm. For these compounds to be used as artificial receptors for amino alcohols and amino acids, the host molecule must possess not only negative charges arising from the phosphonate moieties but also a hydrophobic binding site, such as electron-rich aromatic residues. We designed inter alia new dissymmetric macrocycles capable of being involved in three binding modes with guest molecules, viz., hydrogen bonding, electrostatic attraction, and π-cation interactions. The NMR characterization of the macrocycles, their stereochemistry in solution and in the solid state, and the use as chiral receptors for biologically relevant molecules are described. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1313–1330, June, 2005.     

Synthesis,photochromism, and complexing ability of new derivatives of N-aminofulgimide

On the basis of N-aminofulgimide two new photochromic compounds of the fulgimide class were synthesized. The performed spectral-kinetic studies have shown that the obtained fulgimide derivatives suffer thermally irreversible transformation similar to those observed for the starting N-aminofulgimide except for the absorption bands of the corresponding cyclic forms to undergo red shift. One of the obtained compounds is capable to form complexes with rare-earth metal ions.     

Synthesis,structure, and complexing ability of pyrrole-2-carbaldehyde ferrocenoylhydrazone

A new ligand system based on pyrrole-2-carbaldehyde and ferrocenecarboxylic acid hydrazide was synthesized. Its tautomerism and complexing ability with respect to ions of bivalent metals: zinc, cadmium, and palladium were studied. The structure of the synthesized compounds was investigated by means of the density functional theory (DFT) calculations and spectral methods.     

N-aryl-and N-vinyldiaza-18-crown-6: Synthesis and complexing ability

The nucleophilic aromatic and vinyl substitution using diaza-18-crown-6 as nucleophile afforded a number of its N,N’-diaryl-[aryl = 2,4-(NO₂)₂C₆H₃, 4-C₅F₄N, 4-CF₃C₆F₄] and N,N’-dialkenyl-substituted derivatives [alkenyl = PhC(O)CH=CH, MeOCOCH=CH, (EtO₂C)₂C=C(Ph), etc.]. Arylation of diaza-18-crown-6 with nonactivated aryl bromides, such as 4-Me₂NC₆H₄Br, 4-MeOC₆H₄Br, C₆H₅Br, and 4-CF₃C₆H₄Br, was effected under catalysis by palladium complexes. N,N’-Diaryldiaza-18-crowns-6 having electron-acceptor substituents in the aromatic rings turned out to be incapable of forming complexes with metal cations, while their analogs containing electron-donor para-methoxy and para-dimethylamino groups gave complexes with barium perchlorate.     

The complexing ability and structure of Si-substituted silatranes

The proton NMR spectra of Si-substituted silatranes, a new class of biologically active compounds, measured in the presence of Co²⁺, Ni²⁺ and Eu³⁺ ions are examined. These silatranes coordinate with Co²⁺ and Ni²⁺ through a nitrogen atom and with Eu³⁺ through an oxygen atom mainly without transition to the exo-form. The electronic structure of nitrogen in silatranes is the same as that of pyrrol nitrogen. This suggests that in silatranes a nitrogen lone pair and oxygen lone pairs form common electron system analogous, for example, to the π-system of unsaturated cycles.     

2-(2-pyridyl)-3-thioindan-1-one: Synthesis,tautomerism, and complexing properties

Chelate and molecular complexes of 2-(2-pyridyl)-3-thioindan-1-one were prepared. The structure of the ligand (prevalent tautomeric form), including the coordination mode, was proved by ¹H NMR, IR, and EXAFS spectroscopy and by quantum-chemical calculations. The soft-hard properties of the ligand were demonstrated.     

Synthesis,spectra, and complexing properties of polyoxyethylene-substituted 5,15-diphenylporphyrins

Porphyrins with two opposite meso-phenyl substituents of the macroring linked via o-positions by polyoxyethylene bridges of various lengths were prepared. Their spectra and complexing properties toward Zn²⁺ and 1,4-diazabicyclo[2.2.2]octane were examined. The rate constants of formation and stability constants of the corresponding complexes were determined, and the concentration ranges of their formation were evaluated.     

The complexing ability of crown ethers incorporating glucose

The complexing (in CHCl₃) and extracting abilities of 18-crown-6 type compounds (1–15) were measured with Li, Na, K and NH₄ cations. The substituents on the sugar part affected these properties significantly (K _a=10³–10⁷). Some substituents, like acetyloxy groups (3) decreased whereas others, like tosyloxy groups (10, 11) significantly increased the complexing ability and thus changed the selectivity. The compound with four tosyloxy groups (11) shows an excellent picrate salt extracting ability in a CH₂Cl₂-water system.     

Probing the metal complexing ability of bis-quinolizidine N-oxides: Synthesis, spectroscopy and crystal structures

New ZnX₂ (X = Cl, Br) complexes with sparteine N1-oxide, sparteine epi-N16-oxide, lupanine (2-oxosparteine) N-oxide and α-isosparteine N-oxide were obtained and characterized by spectroscopic and crystallographic methods. Complexation with N1-oxides involves inversion of the configuration at the N16 atom of sparteine, converting its C ring from a boat into a chair form, whereas the structure of sparteine epi-N16-oxide, typified by the trans boat/chair C/D quinolizidine moiety, remains unchanged upon complexation. Coordination of zinc salts in the above compounds is realized solely through the oxygen atom of the N-O group and is accompanied by protonation of the “not-N-oxide” nitrogen atom. At variance lupanine N-oxide forms bis-monodentate complexes with ZnX₂ utilizing both the N-oxide and the lactam carbonyl oxygen atoms to bridge the neighboring ZnX₂ units, while reaction of α-isosparteine N-oxide with ZnX₂ leads to formation of complex salts of the general formula [H(−)α-Sp(N-oxide)][(ZnX₃)(H₂O)].     

Synthesis and complexing properties of phosphoryl-substituted salicylaldimines

Starting from meta and ortho isomers of (diphenylphosphorylmethyl)anilines 2a,b, procedures were developed for the synthesis of new phosphoryl-substituted Schiff bases 3a,b serving as tridentate ligands. In alcoholic solutions, ligands 3a,b form complexes of different composition with praseodymium and neodymium nitrates. Only the M(L)₂(NO₃)₃ complexes crystallized from solution regardless of the reactant ratio. According to the X-ray diffraction study and IR spectroscopy, one of the ligands in the complexes with ortho ligand 3b is coordinated in a bidentate fashion via the oxygen atom of the P=O group and the phenoxy oxygen atom, whereas the second ligand molecule forms a coordination bond with metal only via the phosphoryl oxygen atom. In the Pr(3a)₂(NO₃)₃ complexes, both meta ligands 3a are involved in thebidentate O,O-coordination. Dedicated to Academician G. A. Abakumov on the occasion of his 70th birthday. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1827–1835, September, 2007.     

Biacetyl monooxime ferrocenoylhydrazone and its complexing properties

Biacetyl monooxime ferrocenoylhydrazone has been synthesized and studied by ¹H NMR, IR, and electronic spectroscopy. The electronic absorption spectrum of the title compound in the UV and visible regions has been found to depend on the solvent polarity and pH. Most favorable structures of the hydrazone in solution and gas phase have been determined by quantum chemical calculations. The complexing ability of biacetyl monooxime ferrocenoylhydrazone toward copper(II), nickel(II), and zinc(II) ions has been estimated.     

An infrared study of the complexing ability of manganese phthalocyanine

The complexing ability of manganese phthalocyanine (MnPhc) in the solid state has been studied in detail using i.r. spectroscopy. It has been shown that in its α modification, MnPhc readily adsorbs phenol, pyridine and formic acid. Nothing happens with the β modification. The results have been compared to previous studies and they are explained in terms of valence bond model and molecular orbital model.     

硒杂冠醚的合成及其络合性能研究

本文改进了冠醚的合成方法, 采用双(2-羟基乙基)硒醚与二醇的二对甲苯磺酸酯缩合, 以较高的产率44%得到了多个硒杂冠醚。     

A spirobiscalix[4]azacrown: synthesis and complexing properties

The synthesis and complexation properties of a novel type of calix[4]azacrown, in which two cone calix[4]arenes are linked via a spiro C-atom incorporated into polyaminoalkylene chains are presented.     

Synthesis,characterization, and complexing properties of a polymethacrylate bearing pendant macroheterocyclic structures

The synthesis of a polymerizable methacrylate bearing the dibenzo-18-crown-6 moiety ( 5 ) was effected in three steps by condensation of 3,4-dihydroxybenzaldehyde with 1,2-bis[2′-(2″-chloroethoxy)ethoxy]benzene ( 2 ), reduction of the resulting 4-formyldibenzo-18-crown-6 ( 3 ) to 4 and subsequent reaction of 4 with methacryloyl chloride. The methacrylate ( 5 ) was polymerized in solution using 2,2′-azobis(isobutyronitrile) (AIBN) as the initiator and gave a solid polymer ( 6 ) having a midrange T_g of 67°C. The polymethacrylate bearing pendant crown-ether structure ( 6 ) was found to effectively complex potassium ions and was clearly more effective in its complexing ability than dibenzo-18-crown-6 ( 7 ) or a polyurethane bearing the dibenzo-18-crown-6 moiety ( 8 ) in the polymer backbone. The subject polymer ( 6 ) was also found to complex and consequently solubilize several metal 7,7,8,8-tetracyanoquinodimethane (TCNQ) salts to give semiconducting compositions. Evidence is given that in the presence of the neutral acceptor molecule, 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), the polymethacrylate ( 6 ) acting as a donor, gives rise to a charge-transfer (C/T) complex.     

Synthesis,crystal structures and complexing ability of difunctionalized copillar[5]arene Schiff bases

An efficient method for the synthesis of some difunctionalized copillar[5]arene Schiff bases from condensation of salicylaldehyde and its 5-chloro, 5-bromo, 3,5-di(t-butyl) substituted derivatives with corresponding diamino-functionalized copillar[5]arene, which were prepared by Gabriel reaction according to the reported method. Single-crystals of six copillar[5]arenes were determined by X-ray diffraction. An ORTEP of compounds showed that the two chains units of Schiff base exist in the outside of the cavity of pillar[5]arene. Furthermore, the complexing ability of these Schiff bases to transition metal ions were investigated by UV and fluorescence spectroscopy.