Synthesis and Properties of Acyclic and Cryptate Europium(III) Complexes Incorporating the 3,3′-Biisoquinoline 2,2′-Dioxide Unit

The lithium and europium(III) cryptates of a macrobicyclic ligand 1 incorporating the 3,3′-biisoquinoline 2,2′-dioxide 2 have been prepared. The Eu(III) complex [Eu(2)₂]Cl₃ has also been obtained. These Eu(III) complexes present characteristic ¹H-NMR spectra containing markedly shifted resonances. They are strongly luminescent; the emission spectra, quantum yields, and lifetimes have been determined.     

Metal‐Ion Sensing Europium(III) Complexes with Bidentate Phosphine Oxide Ligands Containing a 2,2′‐Bipyridine Framework

Novel Eu^III complexes with bidentate phosphine oxide ligands containing a bipyridine framework, i.e., [3,3′‐bis(diphenylphosphoryl)‐2,2′‐bipyridine]tris(hexafluoroacetylacetonato)europium(III) ([Eu(hfa)₃(BIPYPO)]) and [3,3′‐bis(diphenylphosphoryl)‐6,6′‐dimethyl‐2,2′‐bipyridine]tris(hexafluoroacetylacetonato)europium(III) ([Eu(hfa)₃(Me‐BIPYPO)]), were synthesized for lanthanide‐based sensor materials having high emission quantum yields and effective chemosensing properties. The emission quantum yields of [Eu(hfa)₃(BIPYPO)] and [Eu(hfa)₃(Me‐BIPYPO)] were 71 and 73%, respectively. Metal‐ion sensing properties of the Eu^III complexes were also studied by measuring the emission spectra of Eu^III complexes in the presence of Zn^II or Cu^II ions. The metal‐ion sensing and the photophysical properties of luminescent Eu^III complexes with a bidentate phosphine oxide containing 2,2′‐bipyridine framework are demonstrated for the first time.     

Mono(di)nuclear Europium(III) Complexes of Macrobi(tri)cyclic Cryptands Derived from Diazatetralactams as Luminophores in Aqueous Solution

To increase the excellent light-emitting properties of the Eu³⁺ ion, macrobicyclic and macrotricyclic ligands 7 – 10 , incorporating a 18-membered tetralactam ring (acting as a lanthanide binding site) and a sensitizer group (2,2′-bipyridine or 2,2′-bipyridine 1,1′-dioxide moiety), were synthesized. The mononuclear and dinuclear europium cryptates derived from these ligands were isolated and characterized. Their luminescent properties and those of the corresponding cryptates containing a phenanthroline group (see 11 and 12 ) were examined in H₂O and D₂O solutions at 77 and 300 K. It results that the tetralactam moiety plays a major role in the efficient shielding of the complexed Eu³⁺ ion from the water environment. The cryptands incorporating the bipyridine unit are the most promising labels according to their photophysical properties (excitation maxima, emission decay lifetime, relative luminescent yield). In contrast with literature data, introduction of N-oxide groups in the bipyridine chromophore weakens the luminescence properties of the cryptate.     

Synthesis and NMR characterization of 3,4′-dibutoxy-2,2′-bithiophene

3,4′-Dibromo-2,2′-bithiophene was converted, in high yield, into the corresponding dibutoxy derivative. The ¹H ¹³C and nmr data are discussed in comparison with those of 3,3′- and 4,4′-dibutoxy-2,2′-bithiophene in relation to regiochemistry.     

Reactions of 2,2′,5′,2′-terfuran

Formylation of 2,2′,5′,2′-terfuran ( 1 ) with N-methylformanilide and phosphorus oxychloride gave 5-formyl-2,2′,5′,2′-terfuran ( 2 ) and 5,5′-diformyl-2,2′5′,2′-terfuran ( 3 ). Reduction of 2 and 3 afforded 5-hydroxymethyl-2,2′,5′,2′-terfuran ( 4 ) and 5,5′ dihydroxymethyl-2,2′,5′,2′-terfuran ( 5 ), respectively. Terfuran 1 reacted with phenylmagnesium bromide to give 5-(phenylhydroxymethyl)-2,2′,5′,2′-terfuran ( 6 ), and was carbonated to 5-carboxy 2,2′,5′,2′-terfuran ( 7 ) and 5,5′-dicarboxy-2,2′,5′,2′-terfuran ( 8 ). Bromination of 1 with N-bromosuccinimide gave 5,5′-dibromo 2,2′,5′,2′-terfuran ( 9 ).     

High resolution 1H NMR spectra of 2,2′-biquinoline

From analysis and refinement by the LAOCOON III program of the 220 MHz ¹H spectrum of 2,2′-biquinoline, recorded as a saturated solution in carbon disulphide, most derived chemical shifts and coupling constants are close to corresponding values in quinoline. However, H-3 is at 1.5 ppm lower field in 2,2′-biquinoline than in quinoline and the ortho-coupling ³J(34) in the heterocyclic ring is 0.5 Hz larger in 2,2′-biquinoline than in quinoline; fairly free rotation about the 2,2′ bond is inferred.     

Influence of Chelating Groups on the Luminescence Properties of Europium(III) and Terbium(III) chelates in the 2,2′-bipyridine series

Eight different 2,2′-bipyridine derivatives, i.e. 2, 5, 8, 10, 12, 13, 15 , and 19 (Schemes 1 and 2), were prepared to study the influence of the chelating groups on the luminescence properties of their Eu^III and Tb^III chelates. According to our luminescence results, 2,2′-(methylenenitrilo)bis(acetic acid) as well as (methylenenitrilo)bis-(methylphosphonic acid) in 6- and 6′-position of 2,2′-bipyridine is a suitable group when developing luminescent markers for bioaffinity assays based on time-resolved luminescence measurement.     

Radiative Lifetime,Non-Radiative Relaxation,and Sensitization Efficiency in Luminescent Europium and Neodymium Cryptates – The Roles of 2,2′-Bipyridine-N,N′-dioxide and Deuteration

Five luminescent tris(bipyridine)-based cryptates with the lanthanoids Eu and Nd have been prepared with a systematic increase in the number of 2,2′-bipyridine-N,N′-dioxide units and with different deuteration levels in the complexing cryptands for the europium species. Careful analysis of the radiative lifetime τ_rad in these systems reveals that an increase in N-oxide units around the metal centers uniformly lowers τ_rad by about 30–40 %. The potential involvement of nephelauxetic effects is discussed. Exchange of 30 C−D for C−H oscillators around the europium centers does not affect the radiative lifetimes but decreases non-radiative deactivation and increases the overall luminescence quantum yield in D₂O by 45 %.     

Intramolekulare Cycloaddition von [1,1′-Binaphthyl]-2,2′-bis(allylamin)

Intramolecular cycloaddition of [1,1′-binaphthyl]-2,2′-bis(allylamine) Unlike the 1,1′-binaphthyl-2,2′-bis(allylether) the corresponding [1,1′-binaphthyl]-2,2′-bis(allylamine) (1) upon heating to 230° in mesitylene undergoes thermal decomposition only. However, when 1 is heated in a mixture of 2-methylaminoethanol and water, besides 3 the policyclic ketones 4 and 5 are formed in isolated yields of 28 and 10%, respectively (Scheme 1). Intermediates are the imines corresponding to 4 and 5 which are hydrolysed under the reaction conditions rather than decomposed. The imines are formed by a intramolecular Diels-Alder reaction, in which the double bond of one N-allylgroup reacts with the naphthalene ring of the second half of the molecule. The policyclic ketones 4 and 5 are characterized as acetates 6 and 7 , respectively, and as the acetylated reduced products 11 , and 12 and 13 , respectively. The constitutions of all compounds are derived from spectroscopic data, chiefly from the ¹H-NMR. spectra.     

New symmetric and unsymmetric polyfunctionalized 2,2′-bipyridines

Recently, a large number of biheterocycles have been synthesized in order to build macrobicyclic cryp-tates. To pursue investigations in this field, we prepared new symmetric and unsymmetric functionalized bi-pyridines and we describe here two synthetic strategies leading to new tetrasubstituted 3 to 15 and trisubsti-tuted 17 to 29 bipyridines. Modification at the α,α'-methyl groups and introduction of functionalities in the 4,4′-positions have been performed after N-O activation of the starting 6,6′-dimethyl-2,2′-bipyridine unit. In the case of cyano and hydroxymethyl groups, alkylation of the N-O function followed by a nucleophilic attack with the CN anion or an hydroxymethyl radical allowed us to obtain the dissymmetric species. To understand observed differencies between cyanation and hydroxymethylation processes, the unstable and hygroscopic N-methoxybipyridinium salt 30 has been isolated and characterized by nmr. Dibromomethyl compounds 8, 15, 29 were finally obtained in good to moderate yields by the Boekelheide rearrangement followed by a pseudohalogen exchange.     

Diorganotin(IV) compounds derived from n‐methyl‐2,2′‐diphenolamine and 2,2′‐diphenolamine

The reaction of N‐methyl‐2,2′‐diphenolamine 1 and 2,2′‐diphenolamine 2 with some diorganotin(IV) oxides [R1/2SnO: R¹ = Me, n‐Bu, t‐Bu and Ph] led to the syntheses of diorgano[N‐methyl‐2,2′‐diphenolato‐O,O′,N]tin (IV) 3–6 and diorgano[2,2′‐diphenolato‐O,O′,N]tin (IV) 7–9 . All compounds (except 7 ) studied in this work were characterized by ¹H, ¹³C, ¹¹⁹Sn NMR, infrared, and mass spectroscopy. Their ¹¹⁹Sn NMR data show that the tin atom is tetracoordinated in CDCl₃ but penta and hexacoordinated in DMSO‐d₆. © 1999 John Wiley & Sons, Inc. Heteroatom Chem 10: 133–139, 1999     

Palladium-Catalyzed Syntheses of Polyethynyl-Substituted 2,2′-Bithiophenes

The syntheses of polyethynyl-substituted 2,2′-bithiophenes 2 and related 5,5′-dicarbaldehyde derivatives 1 are described. The treatment of easily available polybrominated 2,2′-bithiophenes 3 and 2,2′-bithiophene-5,5′-dicarbaldehydes 4 with phenyl or (trimethylsilyl)acetylene in the presence of Pd^II and Cu^I in (i-Pr)₂NH yields substituted polyethynyl-2,2′-bithiophene compounds. The Me₃Si protecting groups can be removed by protodesilylation under basic conditions to give the corresponding terminal ethynyl groups. These polyethynyl-bithiophenes could be interesting precursors for the synthesis of macrocycles with interesting properties.     

Dimethyl 2,2′‐bipyridine‐6,6′‐dicarboxylate and bis(dimethyl 2,2′‐bipyridine‐6,6′‐dicarboxylato‐κ2N,N′)copper(I) tetrafluoroborate

The single‐crystal X‐ray structures of dimethyl 2,2′‐bipyridine‐6,6′‐dicarboxylate, C₁₄H₁₂N₂O₄, and the copper(I) coordination complex bis(dimethyl 2,2′‐bipyridine‐6,6′‐dicarboxylato‐κ²N,N′)copper(I) tetrafluoroborate, [Cu(C₁₄H₁₂N₂O₄)₂]BF₄, are reported. The uncoordinated ligand crystallizes across an inversion centre and adopts the anticipated anti pyridyl arrangement with coplanar pyridyl rings. In contrast, upon coordination of copper(I), the ligand adopts an arrangement of pyridyl donors facilitating chelating metal coordination and an increased inter‐pyridyl twisting within each ligand. The distortion of each ligand contrasts with comparable copper(I) complexes of unfunctionalized 2,2′‐bipyridine.     

Synthesis,Modification, and Anticonvulsant Activity of 3′‐R1‐Spiro[indoline‐3,6′‐[1,2,4]triazino[2,3‐c]quinazolin]‐2,2′(7′H)‐diones Derivatives

Previously unknown 3′‐R¹‐5‐R²‐spiro[indoline‐3,6′‐[1,2,4]triazino[2,3‐c]quinazoline]‐2,2′‐(7′H)‐diones and their N‐substituted analogues were obtained via reaction of 6‐R¹‐3‐(2‐aminophenyl)‐1,2,4‐triazin‐5‐ones with isatin and its substituted derivatives. It was shown that alkylation of 3′‐R¹‐5‐R²‐spiro[indoline‐3,6′‐[1,2,4]triazino[2,3‐c]quinazolin]‐2,2′‐(7′H)‐diones by N‐R³‐chloroacetamides or chloroacetonitrile in the presence of а base proceeds by N‐1 atom of isatin fragment. The spectral properties (¹H and ¹³C NMR spectra) of synthesized compounds were studied, and features of spectral patterns were discussed. The high‐effective anticonvulsant and radical scavenging agents among 3′‐R¹‐5‐R²‐spiro[indoline‐3,6′‐[1,2,4]triazino[2,3‐c]quinazolin]‐2,2′(7′H)‐diones and their N‐substituted derivatives were detected. It was shown that compounds 2.2 , 2.8 , and 3.1 exceed or compete the activity of the most widely used in modern neurology drug—lamotrigine on the pentylenetetrazole‐induced seizures model. The aforementioned fact may be considered as a reason for further profound study of synthesized compounds using other pathology models.     

Effect of Metal Ions on the Structures of Coordination Polymers Based on Biphenyl‐2,2′,4,4′‐Tetracarboxylate

Two new coordination polymers, {[Cd₂(btc)(2,2′‐bpy)₂] · H₂O}_n ( 1 ) and [Zn₂(btc)(2,2′‐bpy)(H₂O)]_n ( 2 ) (H₄btc = biphenyl‐2,2′,4,4′‐tetracarboxylic acid, 2,2′‐bpy = 2,2′‐bipyridine), were synthesized hydrothermally under similar conditions and characterized by elemental analysis, IR spectra, TGA, and single‐crystal X‐ray diffraction analysis. In complexes 1 and 2 , the (btc)^4– ligand acts as connectors to link metal ions to give a 2D bilayer network of 1 and a 3D metal‐organic framework of 2 , respectively. The differences in the structures are induced by diverging coordination modes of the (btc)^4– ligand, which can be attributed to the difference metal ions in sizes. The results indicate that metal ions have significant effects on the formation and structures of the final complexes. Additionally, the fluorescent properties of the two complexes were also studied in the solid state at room temperature.     

The synthesis of some 4,4′-disubstituted-2,2′-biquinolines

2,2′-Biquinoline dioxide and 4,4′-dichloro-2,2′-biquinoline have been used for the preparation of the following 4,4′-disubstituted-2,2′-biquinolines: dimethoxy, diethoxy, dihydroxy, dipiperidino, dipyrrolidino, dibromo, diphenoxy, dithiophenoxy, di(p-chloro-phenoxy), di(p-bromophenoxy), di(p-fluorophenoxy), di(β-naphthoxy) and the dinitro dioxide. Molar extinction coefficients have been determined for several of the copper (I) complexes of these compounds.     

Synthesis of C-5 benzoyl and azido functionalized 2,2′-dithiobis-and 2,2′-diselenobis(1H-indoles)

Novel methods for the synthesis of C-5 benzoyl and azido analogues of 2,2′-dithiobis(1H-indole), 1, and 2,2′-diselenobis(1H-indole), 2, are described to further explore the structure activity relationships in this region of the molecule. Analogues 3-i displayed inhibitory activity (IC₅₀ = 0.45-2.03 μ) toward the catalytic domain of the epidermal growth factor receptor tyrosine kinase that was equivalent to or better than that of unsubstituted compounds 1 and 2. The regiochemistry of Friedel-Crafts benzoylation onto 1 was determined by X-ray crystallography. To test the potential for compounds of this class to interact with the epidermal growth factor receptor tyrosine kinase via a sulfhydryl exchange mechanism, reaction of a 2,2′-dithiobis(1H-indole) with glutathione was carried out and the product characterized.     

Synthesis of 2,2′‐(p‐phenylene)bisbenzazoles compounds from terephthalohydroxamoyl chloride

In this study, synthesis of symmetric compounds of 2,2′‐(p‐phenylene)bisbenzothiazole, 2,2′‐(p‐phenyl‐ene)bisbenzimidazole and 5,5′‐dimethyl‐2,2′‐(p‐phenylene)bisbenzoxazole were benefited from the reaction of terephthalohydroxamoyl chloride with 2‐amino‐4‐methyl phenol, o‐aminothio phenol and o‐phenylenedi‐amin compounds. The structures of these compounds were confirmed by elemental analysis, mass, ¹H‐NMR and FT‐IR techniques.     

Synthese und Konfiguration einiger Spiro [indan-2,2′-pyrrolidin]- und Spiro [pyrrolidin-2,2′-tetralin]-Derivate,

Synthesis and configuration of some spiro [indan-2,2′-pyrrolidine] and spiro [pyrrolidine-2,2′-tetraline] derivatives Catalytic hydrogenation of the nitrosoindan and nitrosotetralin derivatives 8 yielded trans-1-hydroxy-spiro [indan-2,2′-pyrrolidin]-5′-one ( 9 ) and trans-1′-hydroxy-spiro [pyrrolidine-2,2′-tetralin]-5-one ( 10 ) respectively, whilst the corresponding cis compounds 12 and 15 were prepared via the chlorides 11 and 14 . The configurations of 10 and 13 were determined by X-Ray analysis.     

Synthesis and Properties of Macrobicyclic Cryptates Incorporating Five- and Six-Membered Biheteroaryl Units

The socium cryptates of the macrobicyclic ligands 1–6 have been synthesized by direct macrobicyclisation or by stepwise procedures. They incorporate 2,2′-bithiazole, 2,2′-biimidazole, 2.2′-bipyrimidine as well as 2,2′-bipyridine units. Treatment of the sodium complexes with europium(III) chloride gave the corresponding Eu^III cryptates. The structural and spectral properties of these compounds are described. The Eu^III complexes present characteristic ¹H-NMR chemical-shift features. Their luminescence properties are described.