Synthetic macrocyclic ligands. II. Synthesis of a photochromic crown ether

A photochromic crown ether with two anthracene nuclei is synthesized and the metal ion dependence of its photo and thermal reactions is studied.     

Synthesis of four novel pendant armed macrocyclic ligands and their interaction with lanthanide(III) cations

The ability of La³⁺ ions to form stable complexes with four novel pendant-armed N_xO_y-macrocycles derived from 2,6-bis(2-formylphenoxymethyl)pyridine, L¹, L², L³, and L⁴, has been studied. The corresponding (unsubstituted) parent ligands were prepared by the reaction between 2,6-bis(2-formylphenoxymethyl)pyridine and three different amines: 1,2-bis(2-aminophenoxy)propane (L¹), diethylenetriamine (L²), and 3,6-dioxa-1,8-octanediamine (L³ and L⁴). This was followed for the parent ligands of L¹, L³, and L⁴ by in situ reduction with sodium borohydride. The pendant-armed ligands were then synthesized by the alkylation of the free-NH groups with p-(L¹ and L³) and o-nitrobenzyl bromide (L⁴), and 2-chloromethylpyridine chlorohydrate (L²). A series of Ln(III) complexes were prepared for the four ligands by the direct synthesis between the corresponding macrocycle and Ln(III) hydrated nitrates and perchlorates. The number of complexes obtained from the pendant-armed macrocycles is lower than that of the (unsubstituted) parent ones, suggesting that the introduction of pendant arms in the macrocyclic skeletons increases the selectivity of the ligands. More complexes were synthesized when using nitrate as the counterion, showing the important role of the counterion in the complexation reaction. The text was submitted by the authors in English.     

Synthesis of macrocyclic ligands containing the indole ring system

2,7-Diformyl-3-methyl-4,6-dimethoxyindole (6) has been synthesized and converted by metal template reactions into the macrocyclic complexes (10–12).     

Synthetic macrocyclic ligands. VI. Lithium ion-selectivefluorescent emission with crowned benzo- and naphtho-thiazolylphenols

Synthesis of fluorescent crowned benzo- and naphtho-thiazolylphenols are described and lithium ion-selective fluorescent emission is observed under the restricted conditions.     

Synthetic macrocyclic ligands. IV. Lithium ion-characteristic coloration of a “crowned” dinitrophenylazophenol

A “crowned” dinitrophenylazophenol shows a characteristic coloration only with lithium ion of alkali metal ions, as if an indicator.     

Synthesis and complexing properties of a chiral macrocyclic molecular receptor with convergent binding sites

Two novel hosts: 15-crown-5 and N-benzyl-aza-15-crown-5 incorporating a boron-containing D-mannopyranosidic unit form more stable cascade complexes with (S)-amino acid sodium or potassium salts than with the respective (R)-enantiomers. Complexes with sodium salts are more stable than the corresponding complexes with potassium salts as revealed by variable-temperature NMR measurements. Strong non-bonded interaction between the sugar unit and the -substituents of the amino acids results in enantiomeric differentiation and destabilization of the complex. Complex formation is interpreted in terms of ion-pair inclusion by macrocyclic ring and nitrogen-boron interaction.     

Synthetic studies toward sarain A. Formation of the western macrocyclic ring

Starting with the tricyclic core 2b, annulation to form the 13-membered western ring of sarain A has been achieved to afford the macrocycle 30a by initial construction of the sterically congested quaternary center at C-3, followed by elaboration of the C-3 side-chain and ring-closing olefin metathesis. Also included is a parallel conversion of tricycle 2c to macrocycle 30b containing a functionalized side-chain at N-1 suitable for attachment of the eastern macrocyclic ring.     

Synthesis and application of macrocyclic binaphthyl ligands with extended chiral bias

Two macrocyclic and one non-cyclic chiral diphosphine ligand containing a 2,2′-bridged binaphthyl unit were synthesized in six steps from (R)-2,2′-dimethoxy-1,1′-binaphthyl in overall yields of 25 and 17%, respectively. The new ligands showed asymmetric inductions of up to 98% e.e. if used in palladium catalyzed allylic alkylation reactions.     

Synthesis and characterization of cobalt(III) tetraaza macrocyclic complexes containing chloro and azido ligands

The complexes [Co(L)Cl₂]Cl · 4H₂O (1) and [Co(L)(N₃)₂]N₃ · 2H₂O (2) (L = 3,14-dimethyl-2,6,13,17-tetraazatricyclo [14,4,0^1.18,0^7.12]docosane) have been synthesized, and structurally characterized by X-ray crystallography, spectroscopy and cyclic voltammetry. The crystal structure of (1) is centrosymmetric and the cobalt(III) atom has an axially elongated octahedral geometry with four nitrogen atoms of the macrocycle and two chloride ligands. The cobalt(III) ion in (2) is coordinated to four nitrogen atoms from the macrocycle, and two azide ligands in an octahedral environment, which forms the 1D polymer through hydrogen bonding contacts involving the cation, azide anion and solvent water molecules. Electronic spectra of the complexes also exhibit a low-spin octahedral environment. Cyclic voltammetry of the complexes undergoes a one-electron wave corresponding to Co(III)/Co(II) processes. The electronic spectra and electrochemical behaviors of the complexes are significantly affected by the nature of the axial ligands.     

Macroheterocycles. 51. Synthesis of macrocyclic polyamines in a biphasic system

Macrocyclic polyamines are conveniently synthesized by condensation of bissulfonamides with ditosylates or dibromides of glycols in the biphasic system toluene(xylene)-aqueous sodium hydroxide.For Communication 50, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 401–404, March, 1990.     

Binuclear and polynuclear transition metal complexes with macrocyclic ligands 7. Directed step-by-step synthesis of novel unsymmetric macrocyclic ligands

Novel asymmetric macrocyclic Schiff bases were synthesized by the condensation of N,N′-bis(2-aminophenyl)-3,4-diphenylthiophene-2,5-dicarboxamide (1) with diformyl derivatives of phenol, furan, difurans, pyridine, pyrrole, and dipyrroles. The reaction proceeds in high yields and without by-products in methanol in the presence of inorganic and organic acids (proton-template condensation). In the case of monocyclic diformyl derivatives and di(5-formylfuran-2-yl) sulfide, the reaction occurs in 1,4-dioxane (templateless synthesis). The synthesized macrocycles were characterized by elemental analysis data and NMR and mass spectra. For Part 6, see Ref. 1. Dedicated to Academician N. S. Zefirov on the occasion of his 70th birthday. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 2152–2156, September, 2005.     

Synthesis,spectroscopic studies,and crystal structure of 2,6-diacetylpyridinediphenylhydrazone perchlorate and its complexing ability toward the lanthanides

2,6-diacetylpyridinediphenylhydrazone perchlorate was prepared and characterized by spectroscopic (IR, ESI–MS, UV–Vis, ¹H NMR) and analytical data and its crystal structure was determined by single X-ray analysis. The lanthanum(III), praseodymium(III), and neodymium(III) perchlorate complexes of 2,6-diacetylpyridinediphenylhydrazone were prepared in a direct reaction of the ligand with appropriate metal perchlorates. The spectroscopic and analytical data indicate 1:2 metal to ligand stoichiometry. In all the complexes the hydrazones act as monodeprotonated terdentate NNN donor chelators. The same lanthanum(III) complex was also obtained in a one-step condensation reaction between 2,6-diacetylpyridine and phenylhydrazine in the presence of lanthanum(III) perchlorate.     

Synthesis of N-octylmonoaza-15-crown-5 having a dodecylphosphoric acid functional group and the binding ability toward alkali metal cations

A new N-octylmonoaza-15-crown-5 having an alkylphosphoric acid functional group ( 3c ) was synthesized. It was revealed that 3c selectively transported sodium ion under neutral source phase/acidic receiving phase condition, and selectively transported lithium ion under basic source phase/acidic receiving phase condition. From an ir and ¹³C nmr spectral study of the lithium hydroxide and sodium thiocyanate complexes of 3c , it is suggested that 3c does not incorporate cations into the three dimensional cavity using the crown ring and the phosphoric acid site, but that the crown and the phosphoric acid sites act on the cations independently; only the crown ether site of 3c significantly coordinates to the cations under neutral source phase condition, and the phosphate anion is mainly employed under basic conditions.     

Synthesis, crystal structures and DNA-binding properties of dinuclear complexes with macrocyclic ligands

Two symmetrical macrocyclic dinuclear complexes, [Cu₂L¹(ClO₄)₂(H₂O)₂][Cu₂L¹(H₂O)₂] (ClO₄)₂ (1) and [Cu₂L²(ClO₄)₂] (2), (where H₂L¹ and H₂L² are the [2?+?2] condensation products of 1,3-diaminopropane with 2,6-diformyl-4-methylphenol and 2,6-diformyl-4-flurophenol, respectively), have been synthesized and characterized. The electronic and magnetic properties of the complexes were studied by cyclic voltammetry and magnetic susceptibility. There are strong antiferromagnetic couplings between the two copper(II) centers in both complexes. The strongly electron-withdrawing fluorine groups in H₂L² weaken the antiferromagnetic exchange, but make the metal centers more easily reduced than its analog H₂L¹. The interactions of the complexes with calf thymus DNA were studied by UV?CVis and CD spectroscopic techniques.     

Synthesis of chiral linear and macrocyclic candidates: III. Synthesis and antimicrobial activity of linear tetrapeptide and macrocyclic pentapeptide Schiff bases

Russian Journal of General Chemistry - A series of tetrapeptide Schiff bases and a macrocyclic pentapeptide were synthesized using N α-dinicotinoyl-bis[L-leucyl-L-phenylalaninyl acid...     

The separation of beryllium from polyvalent cations with a diallyl phosphate complexing resin

The complexing polymer sodium diallyl phosphate (NaDAP) when used in conjunction with disodium ethylene diamine tetraacetate (Na₂EDTA) separates beryllium quantitatively from alkaline earths (Ca and Sr), ferric and divalent cations of the first transitional period, aluminium and lanthanides, cadmium and mercury(II), bismuth and polonium(IV). The high affinity of NaDAP for beryllium should permit its concentration by several orders of magnitude, when present as a minor or trace component in a mixture of polyvalent cations. The results are compared with those obtained using sulphonated resin.     

Binuclear and polynuclear transition metal complexes with macrocyclic ligands. 3. New polydentate macrocyclic ligands in reactions of 4-alkyl-2,6-diformylphenols with 1,2-diaminobenzenes

The mechanism of abnormal condensation of 2,6-diformyl-4-R-phenols with 1,2-diaminobenzenes accompanied by the reduction of two of four double C=N bonds in macrocyclic Schiff"s bases formed was studied by DFT (gradient-corrected PBE functional, TZ2p basis set). In the first step, [1+1] Schiff"s base is formed and disproportionates further to afford amine and benzoimidazolylphenols. Two new macrocyclic polydentate ligands containing two CH₂—NH moieties in the rings were synthesized. The reduction of one of these ligands with sodium borohydride gave the new macrocyclic ligand, whose structure and conformations were studied by the DFT method.     

The structure of a potassium-copper complex with six-membered macrocyclic ethylsiloxanolate ligands

The structure of K₂{[EtSiO₂]₆K₂Cu₄[O₂SiEt]₆} · 4n-BuOH, a novel mixed sandwich-like complex of K⁺ and Cu²⁺ with two 6-membered macrocyclic ethylsiloxanolate ligands, was established by means of X-ray study. The ligands have an all-cis configuration and a crown conformation. Four Cu²⁺ and two K⁺ ions form a planar hexagon sandwiched between antiparallel coaxial macrocyclic ligands. The K⁺ ions occupy two opposite apices of the hexagon. The Cu²⁺ ions have square-planar coordination with four siloxanolate O_M atoms, while the K⁺ ions, are coordinated with two O atoms of the solvating butanol molecules, in addition to four O_M atoms. The electric neutrality of the whole complex is due to the two outer-sphere K⁺ counter-ions, each located over one of the two siloxanolate macrocycles, i.e., over the «decks» of the sandwich and coordinated with endocyclic siloxane O_Si atoms, as in crown-ether complexes.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 752–756, April, 1993.     

Isomeric distribution and catalyzed isomerization of cobalt(III) complexes with pentadentate macrocyclic ligands. importance of hydrogen bonding

We have investigated the isomeric distribution and rearrangement of complexes of the type [CoXLn]2+,3+ (where X = Cl-, OH-, H2O, and Ln represents a pentadentate 13-, 14-, and 15-membered tetra-aza or diaza-dithia (N4 or N2S2) macrocycle bearing a pendant primary amine). The preparative procedures for chloro complexes produced almost exclusively kinetically preferred cis isomers (where the pendant primary amine is cis to the chloro ligand) that can be separated by careful cation-exchange chromatography. For L13 and L14 the so-called cis-V isomer is isolated as the kinetic product, and for L15 the cis-VI form (an N-based diastereomer) is the preferred, while for the L14(S) complex both cis-V and trans-I forms are obtained. All these complexes rearrange to form stable trans isomers in which the pendent primary amine is trans to the monodentate aqua or hydroxo ligand, depending on pH and the workup procedure. In total 11 different complexes have been studied. From these, two different trans isomers of [CoClL14(S)]2+ have been characterized crystallographically for the first time in addition to a new structure of cis-V-[CoClL14(S)]2+; all were isolated as their chloride perchlorate salts. Two additional isomers have been identified and characterized by NMR as reaction intermediates. The remaining seven forms correspond to the complexes already known, produced in preparative procedures. The kinetic, thermal, and baric activation parameters for all the isomerization reactions have been determined and involve large activation enthalpies and positive volumes of activation. Activation entropies indicate a very important degree of hydrogen bonding in the reactivity of the complexes, confirmed by density functional theory studies on the stability of the different isomeric forms. The isomerization processes are not simple and even some unstable intermediates have been detected and characterized as part of the above-mentioned 11 forms of the complexes. A common reaction mechanism for the isomerization reactions has been proposed for all the complexes derived from the observed kinetic and solution behavior.