Crystallographic report: Crystal structure of bis[dipyrido[3,2,‐a:2′,3′‐c]phenazine]lead(II)diiodide

The mononuclear lead(II) complex of formula [PbI₂(DPPZ)₂] (DPPZ = dipyrido[3,2,‐a:2′,3′‐c]phenazine) has two‐fold symmetry and features a distorted octahedral geometry for lead defined by an N₄I₂ donor set. Copyright © 2004 John Wiley & Sons, Ltd.     

π‐Stacking Modulates the Luminescence of [(dppz)Ni(Mes)Br] (dppz = dipyrido[3,2‐a:2′,3′‐c]phenazine,Mes = 2,4,6‐trimethylphenyl)

The red colour of the novel organonickel complex [(dppz)Ni(Mes)Br] (dppz = dipyrido[3,2‐a:2′,3′‐c]phenazine, Mes = 2,4,6‐trimethylphenyl) originates from long‐wavelength MLCT/L′LCT charge transfer bands. However, luminescence in dilute solution comes presumably from the ³π‐π* (phenazine) excited state. The red‐shifted emission exhibited in concentrated solutions is assigned to dimers. In the solid state emission is quenched. The crystal structure reveals two different types of π‐π stacking along the crystallographic a axis.     

Synthesis of ruthenium complexes with carbonyl and polypyridyl ligands derived from dipyrido[3,2‐a:2′,3′‐c]phenazine: application to the water gas shift reaction

The preparation and spectroscopic properties of new dipyrido[3,2‐a:2′,3′‐c]phenazine ruthenium complexes are described. The complexes show high catalytic activity in the water gas shift reaction in a basic medium under mild conditions (P_CO = 0.9 atm at 100 °C). Copyright © 2002 John Wiley & Sons, Ltd.     

Crystallographic report: Crystal structure of a one‐dimensional zinc(II) coordination polymer containing 4,4′‐biphenyldicarboxylate hemihydrate

A one‐dimensional zinc(II) coordination polymer has been constructed from zinc(II), 4,4′‐biphenyldicarboxylate and pyridine in which each zinc(II) atom is coordinated by two pyridine ligands and two monodentate 4,4′‐biphenyldicarboxylate ligands that define a distorted tetrahedral geometry. Copyright © 2003 John Wiley & Sons, Ltd.     

Design and spectroscopic study of new ruthenium(II) complexes containing ligands derived from terpyridine and dipyrido[3,2‐a:2′,3′‐c]phenazine: {Ru(4′‐Rph‐tpy) [dppz(COOH)]Cl}PF6 with R = NO2, Br,Cl

A series of polypyridine ruthenium complexes of the general formula {Ru(Rph‐tpy)[dppz(COOH)]Cl} PF₆ with R = Br ( 1 ), Cl ( 2 ), NO₂ ( 3 ) where Rph‐tpy is 4′‐(4‐Rphenyl‐2,2′:6′,2″‐terpyridine and dppz(COOH) is dipyrido[3,2‐a:2′,3′‐c]phenazine‐2‐carboxylic acid were prepared and characterized. These complexes display intense metal‐to‐ligand charge‐transfer (MLCT) bands centered about 500 nm. The effect of pH on the absorption spectra of these complexes consisting of protonatable ligands has been investigated in water solution by spectrophotometric titration. The electrochemistry shows oxidation potentials for the Ru(II)–Ru(III) couple at +0.881 ( 1 ), +0.907 ( 2 ) and +0.447 V ( 3 ), respectively. Copyright © 2006 John Wiley & Sons, Ltd.     

Synthesis of β‐Lactam‐containing Pyrido[3′,2′:4,5]thieno[3,2‐e][1,4]diazepines

Novel tricyclic 1,4‐diazepine derivatives – pyrido[3′,2′:4,5]thieno[3,2‐e ][1,4]diazepin‐2‐ones – have been synthesized. Azetidin‐2‐one moiety has been incorporated into the 1,4‐diazepine scaffold by [2 + 2]cycloaddition of functionalized ketenes to imine C═N bond, and several tetracyclic azetodiazepines which can be considered as potential compounds of biological interest have been prepared. Stereoselectivity of the cycloaddition was proved by NMR and X‐ray analysis data.     

Nitration of dithieno[3,2-b:3′,2′-d]pyridine and dithieno[3,2-b:3′,4′-d]pyridine

Nitration of dithieno[3,2-b:3′,2′-d]pyridine ( 4 ) and dithieno[3,2-b:3′,4′-d]pyridine ( 5 ) has been studied. Nitration of 4 occurred in both positions of the C ring, while 5 was predominantly substituted on the 3,4-fused ring. The structures of the nitro derivatives were proven by extensive use of ¹H and ¹³C nmr spectroscopy.     

A novel cadmium(II) coordination polymer containing two kinds of independent one‐dimensional chain

The structure of the title compound, catena‐poly[[cadmium(II)‐di‐μ‐chlorido‐μ‐(1,4‐diazoniabicyclo[2.2.2]octane‐1‐carboxylato)] [[aquachloridocadmium(II)]‐di‐μ‐chlorido] dihydrate], {[Cd(C₈H₁₅N₂O₂)Cl₂][CdCl₃(H₂O)]·2H₂O}_n, contains two kinds of independent one‐dimensional chain, viz. {[Cd(C₈H₁₅N₂O₂)Cl₂]⁺}_n and {[CdCl₃(H₂O)]⁻}_n, and uncoordinated water molecules. Each Cd^II cation in the {[Cd(C₈H₁₅N₂O₂)Cl₂]⁺}_n chain is octahedrally coordinated by two pairs of bridging chloride ligands and two O atoms from different bridging carboxylate groups. Cd^II cations in the {[CdCl₃(H₂O)]⁻}_n chain are also octahedrally surrounded by four bridging chloride ligands, one terminal chloride ligand and one coordinated water molecule. Hydrogen bonds between solvent water molecules and these two independent chains generate a three‐dimensional framework containing two‐dimensional zigzag layers.<!?tpb=18pt>     

Synthesis and Reactions of Naphtho[1′,2′:4,5]Furo[3,2‐b]Pyridine and Naphtho[1′,2′:4,5]Furo[3,2‐d]Pyrimidine Derivatives

2‐Acyl‐3‐aminonaphtho[2,1‐b]furan ( 1 ) reacts with activated methylene such as malono nitrile or ethyl cyanoacetate to afford naphtho[1′,2′:4,5]furo[3,2‐b]pyridine 2a,b . Chloroacylation of the amino group in compound ( 1 ) gave compound 3 which reacts with different amines to produce compound 4 .     

Molecular and Crystal Structure of an Organoplatinum(II) Complex with Dipyrido[3,2-a : 2′,3′-c]phenazine (dppz)

The dimesitylplatinum(II) complex PtMes₂(dppz) (Mes = mesityl = 2,4,6-trimethylphenyl) crystallizes with one equivalent of toluene (C₄₃H₄₀N₄Pt, monoclinic, P2₁/c, Z = 4, a = 14.3551(14) Å, b = 15.8319(14) Å, c = 15.369(2) Å, β = 96.784(6)°). The (dppz)Pt(C1_Mes)₂ part of the molecule was found to be planar, the mesityl substituents adopting dihedral angles of 70.3° and 85.5° with that plane. The photoemissive and reversibly reducible and oxidizable complex molecules form pairs in the crystal with the planar phenazine π “tails” overlapping in graphite-like fashion at 3.427 Å distance. The results are discussed in comparision with a recently reported structure of PtCl₂(dppz).     

A Synthetic,Structural, Spectroscopic and DFT study of ReI,CuI, RuII and IrIII Complexes Containing Functionalised Dipyrido[3,2‐a:2′,3′‐c]phenazine (dppz)

The ligands 11‐cyanodipyrido[3,2‐a:2′,3′‐c]phenazine and 2‐(11‐dipyrido[3,2‐a:2′,3′‐c]phenazine)‐5‐phenyl‐1,3,4‐oxadiazole have been coordinated to Re^I, Cu^I, Ru^II and Ir^III metal centres. Single‐crystal X‐ray analyses were performed on fac‐chlorotricarbonyl(11‐cyanodipyrido[3,2‐a:2′,3′‐c]phenazine)rhenium (C₂₂H₉ClN₅O₃Re, a=6.509(5), b=12.403(5), c=13.907(5) Å, α=96.88(5), β=92.41(5), γ=92.13(5)°, triclinic, P , Z=2) and bis‐2,2′‐bipyridyl(2‐(11‐dipyrido[3,2‐a:2′,3′‐c]phenazine)‐5‐phenyl‐1,3,4‐oxadiazole)ruthenium triflate ? 2 CH₃CN (C₅₂H₃₆F₆N₁₂O₈RuS₂, a=10.601(5), b=12.420(5), c=20.066(5) Å, α=92.846(5), β=96.493(5), γ=103.720(5)°, triclinic, P , Z=2). The ground‐ and excited‐state properties of the ligands and complexes have been investigated with a range of techniques, including electrochemistry, absorption and emission spectroscopy, spectroelectrochemistry and excited‐state lifetime studies. Spectroscopic, time‐resolved and DFT studies reveal that the ligand‐centred (LC) transitions and their resultant excited states play an important role in the photophysical properties of the complexes. Evidence for the presence of lower‐lying metal‐to‐ligand charge‐transfer transitions is obtained from resonance Raman spectroscopy, but nanosecond transient Raman experiments suggest that once excited, the ³LC state is populated.     

A one‐dimensional zinc(II) coordination polymer incorporating [1,1′‐biphenyl]‐4,4′‐dicarboxylate and N,N′‐bis(pyridin‐3‐ylmethyl)‐[1,1′‐biphenyl]‐4,4′‐dicarboxamide ligands

In the title compound, catena‐poly[[[N,N′‐bis(pyridin‐3‐ylmethyl)‐[1,1′‐biphenyl]‐4,4′‐dicarboxamide]chloridozinc(II)]‐μ‐[1,1′‐biphenyl]‐4,4′‐dicarboxylato‐[[N,N′‐bis(pyridin‐3‐ylmethyl)‐[1,1′‐biphenyl]‐4,4′‐dicarboxamide]chloridozinc(II)]‐μ‐[N,N′‐bis(pyridin‐3‐ylmethyl)‐[1,1′‐biphenyl]‐4,4′‐dicarboxamide]], [Zn₂(C₁₄H₈O₄)Cl₂(C₂₆H₂₂N₄O₂)₃]_n, the Zn^II centre is four‐coordinate and approximately tetrahedral, bonding to one carboxylate O atom from a bidentate bridging dianionic [1,1′‐biphenyl]‐4,4′‐dicarboxylate ligand, to two pyridine N atoms from two N,N′‐bis(pyridin‐3‐ylmethyl)‐[1,1′‐biphenyl]‐4,4′‐dicarboxamide ligands and to one chloride ligand. The pyridyl ligands exhibit bidentate bridging and monodentate terminal coordination modes. The bidentate bridging pyridyl ligand and the bridging [1,1′‐biphenyl]‐4,4′‐dicarboxylate ligand both lie on special positions, with inversion centres at the mid‐points of their central C—C bonds. These bridging groups link the Zn^II centres into a one‐dimensional tape structure that propagates along the crystallographic b direction. The tapes are interlinked into a two‐dimensional layer in the ab plane through N—H...O hydrogen bonds between the monodentate ligands. In addition, the thermal stability and solid‐state photoluminescence properties of the title compound are reported.     

A one‐dimensional heterometallic coordination polymer with a three‐dimensional supramolecular framework: poly[μ2‐aqua‐diaqua(2,2′‐bipyridyl)(μ5‐2‐sulfonatobutanedioato)copper(II)sodium(I)]

The title compound, [CuNa(C₄H₃O₇S)(C₁₀H₈N₂)(H₂O)₃]_n, consists of one Cu^II cation, one Na^I cation, one 2‐sulfonatobutanedioate trianion (SSC³⁻), one 2,2′‐bipyridyl (bpy) ligand and three coordinated water molecules as the building unit. The coordination of the Cu^II cation is composed of two pyridyl N atoms, one water O atom and two carboxylate O atoms in a distorted square‐pyramidal coordination geometry with an axial elongation. The Na^I cation is six‐coordinated by three water molecules and three carboxylate O atoms from three SSC³⁻ ligands in a distorted octahedral geometry. Two SSC³⁻ ligands link two Cu^II cations to form a Cu₂(SSC)₂(bpy)₂ macrocyclic unit lying across an inversion centre, which is further linked by Na^I cations via Na—O bonds to give a one‐dimensional chain. Interchain hydrogen bonds link these chains to form a two‐dimensional layer, which is further extended into a three‐dimensional supramolecular framework through π–π stacking interactions. The thermal stability of the title compound has also been investigated.     

A one‐dimensional CdII coordination polymer: catena‐poly[cadmium(II)‐bis(μ‐6‐methylpicolinato)]

In the title compound, [Cd(C₇H₆NO₂)₂]_n, the Cd^II ion has a distorted octahedral geometry. The 6‐methylpyridine‐2‐carboxylate anions are perpendicular to one another and act as bidentate and bridging ligands. Two carboxylate O atoms bridge the Cd^II ions, forming centrosymmetric dinuclear units. These units are further connected via carboxylate O atoms into a one‐dimensional polymeric chain which extends in the [100] direction.     

Synthesis of novel pyrido[3′,2′:4,5]thieno[3,2‐d]pyrimidines,pyrido[3″,2″:4′,5′]thieno[3′,2′:4,5]pyrimido[l,6‐a]benzimidazoles and related fused systems

3‐Amino‐4‐aryl‐5‐ethoxycarbonyl‐6‐methylthieno[2,3‐b]pyridine‐2‐carboxamides 3a‐c were prepared from ethyl 4‐aryl‐3‐cyano‐6‐methyl‐2‐thioxo‐1,2‐dihydropyridine‐5‐carbonylates 1a‐c and reacted with some carbonyl compounds to give tetrahydropyridothienopyrimidine derivatives 6a‐c, 7a‐c and 8a‐c , respectively. Treatment of compound 3c with chloroacetyl chloride led to the formation of a next key compound, ethyl 2‐chloromethyl‐4‐oxo‐3,4‐dihydropyrido[3′,2′:4,5]thieno[3,2‐d]pyrimidine‐8‐carboxylate 9 . Also, 3‐amino‐2‐benzimidazolylthieno[2,3‐b]pyridine‐5‐carboxylate 5 and 2‐(3′‐aminothieno [2,3‐b]pyridin‐2′‐yl)‐4‐oxo‐3,4‐dihydropyrido[3′,2′:4,5]thieno[3,2‐d]pyrimidine‐8‐carboxylate 17 were prepared from 1c. The compounds 5, 9 and 17 were used as good synthons for other pyridothienopyrimidines and pyridothienopyrimidobenzimidazoles as well as for related fused polyheterocyclic systems.     

Cyclometalated iridium(III) complex of 6‐hydroxydipyrido[3,2‐a:2′,3′‐c]phenazine: synthesis,and acid–base and avid DNA binding properties

A new cyclometalated Ir(III) complex [Ir(ppy)₂(hdppz)]PF₆ (Hppy = 2‐phenylpyridine and hdppz = 6‐hydroxydipyrido[3,2‐a:2′,3′‐c]phenazine) was synthesized and characterized. The pH effects on the UV–vis absorption spectra were studied and ground‐state acid ionization constant pK_a values of the complex were derived. The calf thymus DNA (ct‐DNA) binding properties of the complex were investigated with UV‐vis absorption spectrophotometric titrations, DNA competitive binding with ethidium bromide, DNA melting experiments, viscosity measurements and density functional theory (DFT) calculations. The complex was demonstrated to act as a ct‐DNA intercalator with a large DNA binding constant value of (6.06 ± 0.32) × 10⁶ M ⁻¹ in 50 mM NaCl. The avid DNA binding affinity observed was rationalized by the DFT calculations. Copyright © 2011 John Wiley & Sons, Ltd.     

Synthesis of new heteroaromatic nitrogen ligands: Pyrimido‐[4″,5″:4′,5′]‐thieno[3′,2′:4,5]thieno[3,2‐d]pyrimidines and 1,2,3‐triazine[4″,5″:4′,5′]thieno[3′,2′:4,5]thieno[3,2‐d]‐1,2,3‐triazines

An efficient one‐pot access for the synthesis of the previously unreported tetracyclic fused pyrimido‐[4″,5″:4′,5′]thieno[3′,2′:4,5]thieno[3,2‐d]pyrimidine ( 3 ) and 1,2,3‐triazine[4″,5″:4′,5′]thieno‐[3′,2′:4,5]thieno‐[3,2‐d]‐1,2,3‐triazine ( 5 ) heteroaromatic nitrogen ligands is described. The title compounds 3 and 5 were obtained from 3,4‐diaminothieno[2,3‐b]thiophene‐2,5‐dicarbonitrile and phosgeniminium chloride and sodium nitrite/HCl, respectively. Substituted condensed thieno[2,3‐b]thiophene derivatives 4 and 6 were synthesized by nucleophilic displacement of the chloroderivatives 3 and 5 .     

Synthesis of 5′-halo-2′,3′-lyxo-epoxy and 2′,3′-unsaturated thieno[3,2-d]pyrimidine nucleosides

A series of thieno[3,2-d]pyrimidine-2,4-dione nucleosides modified in the carbohydrate moiety has been synthesized. In the first part, synthetic routes are described for the replacement of 5′-hydroxyl group in preformed 1-(β-D-ribofuranosyl)thieno[3,2-d]pyrimidine-2,4-dione I by fluoro, iodo or chloro atoms. Reduction of the 5′-iodo substituent of VI was then carried out catalytically using palladium on carbon as catalyst to give the expected 5′-deoxy derivative VIII. The lyxo-epoxide derivative XII was then synthesized by sequential treatment of the 5′-deoxy-5′-chloro derivative X with methanesulfonyl chloride and with sodium hydroxide. In the second part, most of attention has been devoted to apply different methods reported in the literature that allow access to 2′,3′-olefinic derivatives from the corresponding 2′,3′-dihydroxy precursor. The 5′-O-silyl protected bisxanthate XIV either on reduction with tri-n-butyltin hydride or by reductive elimination of the haloacetate XVI afforded the free 2′,3′-olefin nucleoside after removal of the 5′-protecting group. However none of the compounds in this series exhibited significant antiviral activity against HIV at the doses tested.     

A one‐dimensional cobalt(II) coordination polymer based on 2,4′‐oxydibenzoic acid: poly[[[diaquabis[2‐(4‐carboxyphenoxy)benzoato‐κO1]cobalt(II)]‐μ‐4,4′‐bipyridine‐κ2N:N′] dihydrate]

The reaction of CoSO₄ with 2,4‐oxydibenzoic acid (H₂oba) and 4,4′‐bipyridine (bipy) under hydrothermal condition yielded a new one‐dimensional cobalt(II) coordination polymer, {[Co(C₁₄H₉O₅)₂(C₁₀H₈N₂)(H₂O)₂]·2H₂O}_n, which was characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis, magnetic properties and single‐crystal X‐ray diffraction. The Co^II ions are connected by bipy ligands into infinite one‐dimensional chains. The Hoba⁻ ligands extend out from the two sides of the one‐dimensional chain. O—H...O hydrogen bonding extends these chains into a two‐dimensional supramolecular architecture.     

A 4′‐(4‐carboxyphenyl)‐3,2′:6′,3′′‐terpyridine‐based luminescent cadmium(II) coordination polymer for the detection of 2,4,6‐trinitrophenol

The title coordination polymer, poly[bis[μ3‐4‐(3,2′:6′,3′′‐terpyridin‐4′‐yl)benzoato]cadmium(II)], [Cd(C₂₂H₁₄N₃O₂)₂]_n or [Cd(3‐cptpy)₂]_n, (I), has been synthesized solvothermally and characterized by IR spectroscopy, thermogravimetric analysis, and single‐crystal and powder X‐ray diffraction. The structure is composed of 3‐cptpy^? ligands bridging Cd atoms, with each Cd atom coordinated by six ligands and each ligand coordinating to three Cd atoms. Each Cd atom is in a slightly distorted trans‐N₂O₄ octahedral environment, forming a two‐dimensional layer structure with a (3,6)‐connected topology. Layers are linked to each other by π–π stacking, resulting in a three‐dimensional supramolecular framework. The strong luminescence and good thermal stability of (I) indicate that it can potentially be used as a luminescence sensor. The compound also shows a highly selective and sensitive response to 2,4,6‐trinitrophenol through the luminescence quenching effect.