Mass spectral fragmentation pattern of 2,2′-bipyridyls. Part VIII. 2,2′-Bipyridyl-5-carboxylic Acid and 2,2′-bipyridyl-5-sulphonic acid

The mass spectra of 2,2′-bipyridyl-5-carboxylic acid and 2,2′-bipyridyl-5-sulphonic acid obtained by electron impact are described. The principal initial fragmentation routes from the molecular ion of the carboxylic acid involve loss of CO, CN^˙, HCN, CO₂, OH^˙ and H₂O. From the molecular ion of the sulphonic acid the principal fragmentations are accompanied by loss of HCN, O₃, SO₂ and SO₃.     

Mass spectral fragmentation pattern of 2,2-bipyridyls. Part V. 2,2′-oxydipyridine

The mass spectrum of 2,2′-oxydipyridine obtained by electron impact is reported. The principal fragmentations involve loss of C₂IIO and CO in addition to rupture of the central bonds. Molecular rearrangements accompany the fragmentations.     

Mass spectral fragmentation pattern of 2,2′-bipyridyls. Part XII. 2,2′-Selenodipyridine

The mass spectrum of 2,2′-selenodipyridine obtained by electron impact is reported. The base peak in the spectrum is due to the C₅H₄N⁺ ion formed principally by rupture of the central bonds. The molecular ion gives rise to a peak of 50% of the intensity of the base peak. Other fragmentations include loss of H, Se and CSe from the molecular ion and HCN from the M-1 ion.     

The study and characterization of nucleosides by mass spectrometry—I: The mass spectra of pyrimidine 2,2′-anhydronucleosides and their derivatives

The mass spectra of 2,2′-anhydrouridine, 2,2′-anhydrothymidine and 2,2′-anhydro-4-thiouridine are reported. The acetyl, trifluoroacetyl, trityl, pivaloyl and trimethylsilyl ether derivatives were also studied. Deuterium labeling in acetyl and trimethylsilyl groups aided characterization of many ions in the spectra, as well as helping to clarify hydrogen migration processes. The anhydronucleosides and their derivatives are readily distinguished from natural nucleosides by the presence of an ion containing the base moiety plus the anhydro-ring plus one hydrogen atom from the rest of the molecule. As for natural nucleosides the [base + H]⁺ and [base + 2H]⁺ ions are usually prominent, but in contrast to natural nucleosides, ions characteristic of the sugar moiety do not retain the 2′-oxygen atom (i.e. the oxygen atom of the anhydro-ring). The mass spectra of deuterium labeled derivatives suggest a test for the presence of a 3′-O-acetyl function (the O-acetyl group is lost from the molecular ion much more readily from the 3′- than from the 5′-carbon atom). The trimethylsilyl derivatives showed evidence in their mass spectra for migration of trimethylsilyl groups in addition to hydrogen atoms.     

Mass spectral fragmentation pattern of 2,2′-Bipyridyls. Part IX. 6-Alkoxy-2,2′-bipyridyls

The mass spectral fragmentation patterns of 6-methoxy-, 6-ethoxy- and 6-propoxy-2,2 ′-bipyridyls are reported. The base peaks in the spectra of both the 6-methoxy and 6-ethoxy compounds are due to the M-lion of 6-methoxy-2,2′-bipyridyl, while the base peak with 6-propoxy-2,2- bipyridyl is due to a species formed by loss of C₃H₆ from the molecular ion.     

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.     

Flip‐type disorder in 3‐substituted 2,2′:5′,2′′‐terthiophenes

In the crystal structures of four thiophene derivatives, (E)‐3′‐[2‐(anthracen‐9‐yl)ethenyl]‐2,2′:5′,2′′‐terthiophene, C₂₈H₁₈S₃, (E)‐3′‐[2‐(1‐pyrenyl)ethenyl]‐2,2′:5′,2′′‐terthiophene, C₃₀H₁₈S₃, (E)‐3′‐[2‐(3,4‐dimethoxyphenyl)ethenyl]‐2,2′:5′,2′′‐terthiophene, C₂₂H₁₈O₂S₃, and (E,E)‐1,4‐bis[2‐(2,2′:5′,2′′‐terthiophen‐3′‐yl)ethenyl]‐2,5‐dimethoxybenzene, C₃₆H₂₆O₂S₆, at least one of the terminal thiophene rings is disordered and the disorder is of the flip type. The terthiophene fragments are far from being coplanar, contrary to terthiophene itself. The central C—C=C—C fragments are almost planar but the bond lengths suggest slight delocalization within this fragment. The crystal packing is determined by van der Waals interactions and some weak, relatively short, C—H...S and C—H...π directional contacts.     

Halochrome Moleküle 9. Mitteilung[1]. Substituierte 6,11-Dihydrospiro[[1]benzopyrano[4,3-b]indol-6,9′-9′H-xanthen]-2′,6′-diamine und ihre Aza-analogen: Neue Chromogene für schwarze Farbbilder

Halochromic Molecules. Substituted 6,11-Dihydrospiro[[1]benzopyrano[4,3-b]indol-6,9′-9′H-xanthene]-2′,6′-diamines and Their Aza Analogues: New Chromogenes for Black Images . We have synthesized a series of substituted 6,11-dihydrospiro[[1]benzopyrano[4,3-b]indo1-6,9′-9′H-xanthene]-2′,6′-diamines and their respective aza analogues. These compounds develop a black colour in acidic media. The assumed structures of the analytically pure starting and final products are consistant with the fragmentations in the MS and are also supported by FT ¹H-NMR. The UV/VIS spectra in buffered MeOH/H₂O solutions were measured. From the ?_pH* curves, we determined the pK* values. The title compounds can be used in so-called pressure-sensitive copying systems.     

Four novel lanthanide complexes with 4‐ethylbenzoic acid and 5,5′‐dimethy‐2,2′‐bipyridine: Structures,luminescent, thermal properties and bacteriostatic activities

Four new lanthanide complexes [Ln(4‐EBA)₃(5,5′‐DM‐2,2′‐bipy)]₂·2C₂H₅OH (Ln = Ho ( 1 ), Tb ( 2 ), Er ( 3 )); [Ln(4‐EBA)₃(4‐EBAH)(5,5′‐DM‐2,2′‐bipy)]₂ (Ln = Eu( 4 ); 4‐EBA =4‐ethylbenzoate; 5,5′‐DM‐2,2′‐bipy =5,5′‐dimethy‐2,2′‐bipyridine; 4‐EBAH = 4‐ethylbenzoic acid) have been synthesized and characterized by elemental analysis and IR spectra. The single crystal results reveal that complexes 1 – 3 are isostructural. It is worth noting that the mole ratios of the carboxylate ligands and neutral ligands is 4:1 in complex 4 , which is different from the former and has been rarely reported. Nevertheless, all complexes are connected to form 1D chain by π ···π wake staking interactions. Additionally, the complexes 2 (Tb(III)) and 4 (Eu(III)) exhibit characteristic luminescent properties, indicating that ligands can be used as sensitizing chromophore in these systems. The thermal decomposition mechanism of the complexes has been investigated by TG/DSC–FTIR technology. Stacked plots of the FTIR spectra of the evolved gases show complexes broken down into H₂O, CO₂, and other gaseous molecules as well as the gaseous organic fragments. The studies on bacteriostatic activities of complexes show that four complexes have good bacteriostatic activities against Candida albicans but no bacteriostatic activity on Escherichia coli , and Staphylococcus aureus . Additionally, the complexes 1 to 3 have better bacteriostatic activities on Candida albicans than complex 4 .     

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.     

Conformational Analysis of Biphenyl-2,2′-Diacetate

Conformational analysis of biphenyl-2,2′-diacetate by dynamic NMR and UV spectra and by plots of enzyme activity vs temperature plots is described. From dynamic NMR spectra of the biphenyl-2,2′-diacetate with a chiral shift reagent, the coalescence temperature (T_c), the Gibbs energy of activation (ΔG^≠), and the rate coefficient (k) of bipbenyl-2,2′-diacetate were ?5 °C, 59.5 kJ/mol, and 13.3 s^?1, respectively. From analysis of the conformational break in the UV spectra and the discontinuity in the plots of enzyme activity vs temperature, the racemerization temperature of bipbenyl-2,2′-diacetate is about 5°C.     

Synthesis and Characterization of Heteroleptic Ru(II) Complexes Based on 4,4′‐Bis((E)‐styryl)‐2,2′‐bipyridine as Ancillary Ligand and Application for Dye‐Sensitized Solar Cells

Heteroleptic Ru(II) complexes were designed based on 4,4′‐bis((E)‐styryl)‐2,2′‐bipyridine (bsbpy) as an ancillary ligand for dye‐sensitized solar cells (DSSCs), and those Ru(II) sensitizers, [Ru(L)(bsbpy)(NCS)₂][TBA] (TBA; tetrabutylammonium), were synthesized according to a typical one‐pot reaction of [RuCl₂(p‐cymene)]₂ with the corresponding anchoring ligands (where L = 4,4′‐dicarboxy‐2,2′‐bipyridine (dcbpy), 4,4′‐bis((E)‐carboxyvinyl)‐2,2′‐bipyridine (dcvbpy), 4,7‐dicarboxy‐1,10‐phenanthroline (dcphen), or 4,7‐bis((E)‐carboxyvinyl)‐1,10‐phenanthroline (dcvphen)). The new Ru(II) dyes, [Ru(L)(bsbpy)(NCS)₂][TBA] that incorporated vinyl spacer(s) into ancillary and/or anchoring ligand displayed red‐shifted bands over the overall UV/VIS region relative to the absorption spectra of N719 . A combination of bsbpy ancillary and dcphen anchoring ligand showed the best result for the overall power conversion efficiency (η); i.e., a DSSC fabricated with [Ru(dcphen)(bsbpy)(NCS)₂][TBA] exhibited a power conversion efficiency (η) of 2.98% (compare to N719 , 4.82%).     

μ‐2,2′,6,6′‐Tetramethyl‐4,4′‐bipyridine‐κ2N1:N1′‐bis[(diethylenetriamine‐κ3N,N′,N′′)palladium(II)] tetranitrate

The title compound, [Pd₂(C₄H₁₃N₃)₂(C₁₄H₁₆N₂)](NO₃)₄, comprises discrete tetracationic dumbbell‐type dinuclear complex molecules and noncoordinating nitrate anions. Two Pd(dien)²⁺ moieties (dien is diethylenetriamine) are joined by the rigid linear exo‐bidentate bridging 2,2′,6,6′‐tetramethyl‐4,4′‐bipyridine ligand to form the dinuclear complex, which lies across a centre of inversion in the space group P2₁/n, so that the rings in the 2,2′,6,6′‐tetramethyl‐4,4′‐bipyridine bridging ligand are parallel. In the crystal, the primary and secondary amino groups of the dien ligand act as hydrogen‐bond donors towards the nitrate anions to form a three‐dimensional hydrogen‐bond network.     

Synthesis and photophysical properties of novel amphiphilic ruthenium (II) complexes containing 4,4′‐dialkylaminomethyl‐2,2′‐bipyridyl ligands

The synthesis of a number of new 2,2′‐bipyridine ligands functionalized with bulky amino side groups is reported. Three homoleptic polypyridyl ruthenium (II) complexes, [Ru(L)₃]²⁺ 2(PF₆^?), where L is 4,4′‐dioctylaminomethyl‐2,2′‐bipyridine (Ru4a), 4,4′‐didodecylaminomethyl‐2,2′‐bipyridine (Ru4b) and 4,4′‐dioctadodecylaminomethyl‐2,2′‐bipyridine (Ru4c), have been synthesized. These compounds were characterized and their photophysical properties examined. The electronic spectra of three complexes show pyridyl π → π* transitions in the UV region and metal‐to‐ligand charge transfer bands in the visible region. Copyright © 2005 John Wiley & Sons, Ltd.     

Synthesis and Properties of Sodium and Europium(III) Cryptates Incorporating the 2,2′-Bipyridine 1,1′-Dioxide and 3,3′-Biisoquinoline 2,2′-Dioxide Units

The sodium and europium cryptates of the new macrobicyclic ligands 2 and 3 incorporating the 2,2′-bipyri dine 1,1′-dioxide and 3,3′-biisoquinoline 2,2′-dioxide units, respectively, have been prepared. The Eu^III complexes present characteristic ¹H-NMR spectra, showing large shifts, and are strongly luminescent in aqueous solution. These markedly improved luminescent properties, compared to the europium cryptate of the parent macrobicyclic ligand 1 , may be ascribed at least in part to a better shielding of the bound cation by the N-oxide sites.     

Masking of Lewis acidity trends in the solid‐state structures of trichlorido‐ and tribromido(2,2′:6′,2′′‐terpyridine‐κ3N,N′,N′′)gallium(III)

The molecular structures of trichlorido(2,2′:6′,2′′‐terpyridine‐κ³N,N′,N′′)gallium(III), [GaCl₃(C₁₅H₁₁N₃)], and tribromido(2,2′:6′,2′′‐terpyridine‐κ³N,N′,N′′)gallium(III), [GaBr₃(C₁₅H₁₁N₃)], are isostructural, with the Ga^III atom displaying an octahedral geometry. It is shown that the Ga—N distances in the two complexes are the same within experimental error, in contrast to expected bond lengthening in the bromide complex due to the lower Lewis acidity of GaBr₃. Thus, masking of the Lewis acidity trends in the solid state is observed not only for complexes of group 13 metal halides with monodentate ligands but for complexes with the polydentate 2,2′:6′,2′′‐terpyridine donor as well.     

1,1′‐Di(hydrazinocarbonylmethyl)‐2,2′‐biimidazole monohydrate and 1,1′‐di[2‐(hydrazinocarbonyl)ethyl]‐2,2′‐bi­imidazole

The crystal structures of the title compounds, alternatively called 2,2′‐(2,2′‐bi­imid­azole‐1,1′‐diyl)­diaceto­hydra­zide monohydrate, C₁₀H₁₄N₈O₂·H₂O, (I), and 3,3′‐(2,2′‐bi­imid­azole‐1,1′‐diyl)­dipropion­o­hydra­zide, C₁₂H₁₈N₈O₂, (II), respectively, have been determined. The mol­ecules consist of half‐mol­ecule asymmetric units related by a twofold rotation in (I) and by a center of inversion in (II). The imidazole rings of both mol­ecules crystallize in a nearly coplanar fashion [dihedral angles of 5.91 (3) and 0.0 (1)° for (I) and (II), respectively]. Both planar hy­dra­zinocarbonylalkyl substituents are essentially planar and assume the E orientation.     

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.     

Schwingungsspektren von Komplexen des Gold(III)-chlorids mit 2,2′- und 4,4′-Dipyridin

Vibrational Spectra of Complexes of Gold Trichloride with 2,2′-Dipyridne and 4,4′-Dipyridine, Dipyridine and 4,4′-Dipyridine By reaction of Au₂Cl₆ with 2,2′-Dipyridine and 4,4′-Dipyridine, respectively, the complexes [AuCl₂(2,2′-Dipy)][AuCl₄] (I) and [AuCl₂(4,4′-Dipy)]Cl (II) are obtained. IR and Raman spectra show that (I) has a complex chelate structure, whereas (II) is polymeric with cis-configuration of the ligands.     

Syntheses and Reactions of 1′,2′-Unsaturated 2′,3′-Seconucleoside Analogues

The 1′,2′-unsaturated 2′,3′-secoadenosine and 2′,3′-secouridine analogues were synthesized by the regioselective elimination of the corresponding 2′,3′-ditosylates, 2 and 18 , respectively, under basic conditions. The observed regioselectivity may be explained by the higher acidity and, hence, preferential elimination of the anomeric H–C(1′) in comparison to H? C(4′). The retained (tol-4-yl)sulfonyloxy group at C(3′) of 3 allowed the preparation of the 3′-azido, 3′-chloro, and 3′-hydroxy derivatives 5–7 by nucleophilic substitution. ZnBr₂ in dry CH₂Cl₂ was found to be successful in the removal (85%) of the trityl group without any cleavage of the acid-sensitive, ketene-derived N,O-ketal function. In the uridine series, base-promoted regioselective elimination (→ 19 ), nucleophilic displacement of the tosyl group by azide (→ 20 ), and debenzylation of the protected N(3)-imide function gave 1′,2′-unsaturated 5′-O-trityl-3′-azido-secouridine derivative 21 . The same compound was also obtained by the elimination performed on 2,2′-anhydro-3′-azido-3′-azido-3′-deoxy-5′-O-2′,3′-secouridine ( 22 ) that reacted with KO(t-Bu) under opening of the oxazole ring and double-bond formation at C(1′).