Triphenylsilanol–4,4′‐bipyridyl (4/1): the Z′ = 4 polymorph revisited

A fully ordered structure is reported for the polymorph of triphenylsilanol–4,4′‐bipyridyl (4/1), 4C₁₈H₁₆OSi·C₁₀H₈N₂, having Z′ = 4. The asymmetric unit contains four similar but distinct five‐molecule aggregates, in which the central bipyridyl unit is linked to two molecules of triphenylsilanol via O—H...N hydrogen bonds, with a further pair of triphenylsilanol molecules linked to the first pair via O—H...O hydrogen bonds. An extensive series of C—H...π(arene) hydrogen bonds links these aggregates into complex sheets. This structure is compared with a previously reported structure [Bowes, Ferguson, Lough & Glidewell (2003). Acta Cryst. B 59 , 277–286], which was based on an erroneous disordered structural model arising from a false direct‐methods solution with reference to a strong pseudo‐inversion centre.     

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.     

4,4′‐Thio­dipyridinium tetra­chloro­copper(II)

The title compound, (C₁₀H₁₀N₂S)[CuCl₄], was obtained by the reaction of cupric chloride with pyridine‐4‐thiol in a mixture of aceto­nitrile and tetra­hydro­furan, suggesting that the desulfurization and coupling reactions of pyridine‐4‐thiol occurred in the presence of the Cu²⁺ ion. X‐ray diffraction analysis reveals the presence of one 4,4′‐thio­dipyridinium cation, H₂bps²⁺, and one [CuCl₄]²⁻ anion. The cations interact with the anions via N—H⋯Cl hydrogen‐bonding interactions to form a closed `chair' conformation.     

Dichloro(2,2′‐diamino‐4,4′‐bi‐1,3‐thiazole‐N3,N3′)copper(II)

The title complex, [CuCl₂(C₆H₆N₄S₂)], has a flattened tetrahedral coordination. The Cu^II atom is located on a twofold rotation axis and is coordinated by two N atoms from a chelating 2,2′‐di­amino‐4,4′‐bi‐1,3‐thia­zole ligand and by two Cl atoms. Intramolecular hydrogen bonding exists between the amino groups of the 2,2′‐di­amino‐4,4′‐bi‐1,3‐thia­zole ligand and the Cl atoms. The intermolecular separation of 3.425 (1) Å between parallel bi­thia­zole rings suggests there is a π–π interaction between them.     

Bis(4,4′‐bipyridinium) hexa­cyano­platinate(IV) bis­(4,4′‐bipyridine)

In the title compound, (C₁₀H₉N₂)₂[Pt(CN)₆]·2C₁₀H₈N₂ or [(Hbpy)⁺]₂[Pt(CN)₆]²⁻·2bpy, where bpy is 4,4′‐bipyridine, the Hbpy⁺ cations and bpy mol­ecules form a hydrogen‐bonded two‐dimensional cationic approximately square grid parallel to the (110) plane. The [Pt(CN)₆]²⁻ dianions reside in the cavities within this grid, with the nitrile N atoms forming weak hydrogen bonds with the CH groups in the cationic lattice.     

A polymeric ladder complex: catena‐poly­[[[μ‐4,4′‐bipyridyl‐bis­[aqua(p‐amino­benzoato)copper(II)]]‐di‐μ‐4,4′‐bipyridyl] dinitrate tetrahydrate]

The title polymeric ladder complex, {[Cu₂(C₇H₆NO₂)₂(C₁₀H₈N₂)₃(H₂O)₂](NO₃)₂·4H₂O}_n, has been synthesized and spectroscopically characterized. The polymeric nature of the compound involves two non‐equivalent 4,4′‐bipyridyl ligands acting as almost orthogonal bridges joining the metal coordination Jahn–Teller‐distorted octahedra, and forming ladders packed under the influence of hydrogen bonds involving the uncoordinated amino group of the p‐amino­­benzoate ligand, the NO₃⁻ anion and the water mol­ecules.     

A two‐dimensional copper(II) coordination polymer based on 2,4′‐oxybis(benzoate) and 4,4′‐bipyridine

The reaction of Cu(NO₃)₂·3H₂O with 2,4′‐oxybis(benzoic acid) and 4,4′‐bipyridine under hydrothermal conditions produced a new mixed‐ligand two‐dimensional copper(II) coordination polymer, namely poly[[(μ‐4,4′‐bipyridine‐κ²N ,N ′)[μ‐2,4′‐oxybis(benzoato)‐κ⁴O ²,O ^2′:O ⁴,O ^4′]copper(II)] monohydrate], {[Cu(C₁₄H₈O₅)(C₁₀H₈N₂)]·H₂O}_n , which was characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis and single‐crystal X‐ray diffraction. The X‐ray diffraction crystal structure analysis reveals that the Cu^II ions are connected to form a two‐dimensional wave‐like network through 4,4′‐bipyridine and 2,4′‐oxybis(benzoate) ligands. The two‐dimensional layers are expanded into a three‐dimensional supramolecular structure through intermolecular O—H…O and C—H…O hydrogen bonds. Furthermore, magnetic susceptibility measurements indicate that the complex shows weak antiferromagnetic interactions between adjacent Cu^II ions.     

Four (2,2′‐bipyridyl)(ferrocenyl)boronium derivatives

Crystal structures are reported for four (2,2′‐bipyridyl)(ferrocenyl)boronium derivatives, namely (2,2′‐bipyridyl)(ethenyl)(ferrocenyl)boronium hexafluoridophosphate, [Fe(C₅H₅)(C₁₇H₁₅BN₂)]PF₆, (Ib), (2,2′‐bipyridyl)(tert‐butylamino)(ferrocenyl)boronium bromide, [Fe(C₅H₅)(C₁₉H₂₂BN₃)]Br, (IIa), (2,2′‐bipyridyl)(ferrocenyl)(4‐methoxyphenylamino)boronium hexafluoridophosphate acetonitrile hemisolvate, [Fe(C₅H₅)(C₂₂H₂₀BN₃O)]PF₆·0.5CH₃CN, (IIIb), and 1,1′‐bis[(2,2′‐bipyridyl)(cyanomethyl)boronium]ferrocene bis(hexafluoridophosphate), [Fe(C₁₇H₁₄BN₃)₂](PF₆)₂, (IVb). The asymmetric unit of (IIIb) contains two independent cations with very similar conformations. The B atom has a distorted tetrahedral coordination in all four structures. The cyclopentadienyl rings of (Ib), (IIa) and (IIIb) are approximately eclipsed, while a bisecting conformation is found for (IVb). The N—H groups of (IIa) and (IIIb) are shielded by the ferrocenyl and tert‐butyl or phenyl groups and are therefore not involved in hydrogen bonding. The B—N(amine) bond lengths are shortened by delocalization of π‐electrons. In the cations with an amine substituent at boron, the B—N(bipyridyl) bonds are 0.035 (3) Å longer than in the cations with a methylene C atom bonded to boron. A similar lengthening of the B—N(bipyridyl) bonds is found in a survey of related cations with an oxy group attached to the B atom.     

Preparation and physical properties of poly(4,4′‐diamino‐3′‐carbamoylbenzanilide terephthalamide) and poly(4,4′‐diamino‐3′‐carbamoylbenzanilide isophthalamide) films

To prepare thermally stable and high‐performance polymeric films, new solvent‐soluble aromatic polyamides with a carbamoyl pendant group, namely poly(4,4′‐diamino‐3′‐carbamoylbenzanilide terephthalamide) (p‐PDCBTA) and poly(4,4′‐diamino‐3′‐carbamoylbenzanilide isophthalamide) (m‐PDCBTA), were synthesized. The polymers were cyclized at around 200 to 350 °C to form quinazolone and benzoxazinone units along the polymer backbone. The decomposition onset temperatures of the cyclized m‐ and p‐PDCBTAs were 457 and 524 °C, respectively, lower than that of poly(p‐phenylene terephthalamide) (566 °C). For the p‐PDCBTA film drawn by 40% and heat‐treated, the tensile strength and Young's modulus were 421 MPa and 16.4 GPa, respectively. The film cyclized at 350 °C showed a storage modulus (E′) of 1 × 10¹¹ dyne/cm² (10 GPa) over the temperature range of room temperature to 400 °C. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 775–780, 2000     

4,4′‐Bis(2,2,2‐trifluoroethoxymethyl)‐2,2′‐bipyridine

As part of a homologous series of novel polyfluorinated bipyridyl (bpy) ligands, the title compound, C₁₆H₁₄F₆N₂O₂, contains the smallest fluorinated group, viz. CF₃. The molecule resides on a crystallographic inversion centre at the mid‐point of the pyridine C_ipso—C_ipso bond. Therefore, the bpy skeleton lies in an anti conformation to avoid repulsion between the two pyridyl N atoms. Weak intramolecular C—H...N and C—H...O interactions are observed, similar to those in related polyfluorinated bpy–metal complexes. A π–π interaction is observed between the bpy rings of adjacent molecules and this is probably a primary driving force in crystallization. Weak intermolecular C—H...N hydrogen bonding is present between one of the CF₃CH₂– methylene H atoms and a pyridyl N atom related by translation along the [010] direction, in addition to weak benzyl‐type C—H...F interactions to atoms of the terminal CF₃ group. It is of note that the O—CH₂CF₃ bond is almost perpendicular to the bpy plane.     

Square‐grid coordination networks of diaquabis(4,4′‐bipyridyl)copper(II) crosslinked by hydrogen bonds through two monoanions of 1‐benzofuran‐2,3‐dicarboxylic acid and five molecules of water

The title compound, poly[[[diaquacopper(II)]‐di‐μ‐4,4′‐bipyridyl] bis(3‐carboxy‐1‐benzofuran‐2‐carboxylate) pentahydrate], {[Cu(C₁₀H₈N₂)₂(H₂O)₂](C₁₀H₅O₅)₂·5H₂O}_n, crystallizes in a single‐framework architecture. It is composed of two‐dimensional square‐grid coordination networks of 1:2:2 copper–4,4′‐bipyridine–water units, wherein each copper ion coordinates equatorially to four bipyridyl units and axially to two water ligands. The polymeric nets are intercalated by layers of the benzofurandicarboxylic acid monoanions and additional water species. An extensive array of hydrogen bonds interlinks the various components of the structure. The Cu atom and the bipyridyl entities are located on axes of twofold rotation. This study confirms the preferred monoanionic nature of the benzofurandicarboxylic acid molecule. It reveals a rarely observed extended coordination polymer composed only of copper ions and bipyridyl linkers, and an interesting hydrogen‐bonding connectivity between the polymeric layers aided by the benzofurandicarboxylic acid and water components intercalated in the structure.     

Photoinduced Energy Transfer from Poly(N‐vinylcarbazole) to Tricarbonylchloro‐(2,2′‐bipyridyl)rhenium(I)

This work investigates the photoinduced energy transfer from poly(N‐vinylcarbazole) (PVK), as a donor material, to fac‐(2,2′‐bipyridyl)Re(CO)₃Cl, as a catalyst acceptor, for its potential application towards CO₂ reduction. Photoluminescence quenching experiments reveal dynamic quenching through resonance energy transfer in solid donor/acceptor mixtures and in solid/liquid systems. The bimolecular reaction rate constant at solution–film interfaces for the elementary reaction of the excited state with the quencher material could be determined as 8.8(±1.4)×10¹¹ L mol^?1 s^?1 by using Stern–Volmer analysis. This work shows that PVK is an effective and cheap absorber material that can act efficiently as a redox photosensitizer in combination with fac‐(2,2′‐bipyridyl)Re(CO)₃Cl as a catalyst acceptor, which might lead to possible applications in photocatalytic CO₂ reduction.     

Alternating π‐conjugated copolymer of dithiafulvene with 2,2′‐bipyridyl units

A π‐conjugated polymer containing a dithiafulvene unit and a bipyridyl unit was prepared by cycloaddition polymerization of aldothioketene derived from 5,5′‐diethynyl‐2,2′‐bipyridine. Ultraviolet–visible (UV–vis) absorption spectra showed that the π‐conjugation system of the polymer expanded more effectively than that of a benzene analogue of poly(dithiafulvene) obtained from 1,4‐diethynylbenzene. Cyclic voltammetry measurements indicated that the dithiafulvene–bipyridyl polymer was a weaker electron‐donor polymer than the benzene analogue. These results supported the idea that the incorporation of the electron‐accepting bipyridyl moiety into conjugated poly(dithiafulvene) induced an intramolecular charge‐transfer (CT) effect between the units. Treatment of the dithiafulvene–bipyridyl polymer with bis(2,2′‐bipyridyl)dichlororuthenium (II) [Ru(bpy)₂Cl₂] afforded a ruthenium–polymer complex. A cyclic voltammogram of the complex showed broad redox peaks, which indicated electronic interaction between the dithiafulvene and tris(bipyridyl) ruthenium complex. The dithiafulvene–bipyridyl polymer formed CT complexes with 7,7,8,8‐tetracycanoquinodimethane (TCNQ) in dimethyl sulfoxide. The UV–vis absorption indicated that the resulting CT complex contained anion radical of TCNQ and partially charge‐transferred TCNQ. The polymer showed an unusually high electrical conductivity of 3.1 × 10^?4 S/cm in its nondoped state due to the effective donor–acceptor interaction between the bipyridine unit and the dithiafulvene unit. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 4083–4090, 2001     

Crystallographic report: A three‐dimensional coordination polymer: [Zn6(btc)4(4,4′‐bipy)5]n (btc = 1,2,4‐benzenetricarboxylate; 4,4′‐bipy = 4,4′‐bipyridine)

The three‐dimensional (3D) coordination polymer [Zn₆(btc)₄(4,4′‐bipy)₅]_n ( 1 ) (btc = 1,2,4‐benzenetricarboxylate; 4,4′‐bipy = 4,4′‐bipyridine) has been prepared hydrothermally. The zinc(II) centers in 1 are bridged by btc ligands to form a trinuclear subunit, which is further linked by 4,4′‐bipy and btc ligands to construct the 3D coordination architecture. Copyright © 2003 John Wiley & Sons, Ltd.     

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.     

Thermotropic liquid‐crystalline polyesters of 4,4′‐biphenol and phenyl‐substituted 4,4′‐biphenols with 4,4′‐oxybisbenzoic acid

A series of thermotropic polyesters, derived from 4,4′‐biphenol (BP), 3‐phenyl‐4,4′‐biphenol (MPBP), and 3,3′‐bis(phenyl)‐4,4′‐biphenol (DPBP), 4,4′‐oxybisbenzoic acid (4,4′‐OBBA), and other aromatic dicarboxylic acids as comonomers, were prepared by melt polycondensation and were characterized for their thermotropic liquid‐crystalline (LC) properties with a variety of experimental techniques. The homopolymer of BP with 4,4′‐OBBA and its copolymers with either 50 mol % terephthalic acid or 2,6‐naphthalenedicarboxylic acid had relatively high values of the crystal‐to‐nematic transition (448–460 °C), above which each of them formed a nematic LC phase. In contrast, the homopolymers of MPBP and DPBP had low fusion temperatures and low isotropization temperatures and formed nematic melts above the fusion temperatures. Each of these two polymers also exhibited two glass‐transition temperatures, which were associated with vitrified noncrystalline (amorphous) regions and vitrified LC domains, as obtained directly from melt polycondensation. As expected, they had higher glass‐transition temperatures (176–211 °C) than other LC polyesters and had excellent thermal stability (516–567 °C). The fluorescence properties of the homopolymer of DPBP with 4,4′‐OBBA, which was soluble in common organic solvents such as chloroform and tetrahydrofuran, were also included in this study. For example, it had an absorption spectrum (λ_max = 259 and 292 nm), an excitation spectrum (λ_ex = 258 and 292 nm with monitoring at 350 nm), and an emission spectrum (λ_em = 378 nm with excitation at 330 nm) in chloroform. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 40: 141–155, 2002     

4,4′‐Methylenediphenol–4,4′‐bipyridine (2/3): decarboxylation of 5,5′‐methylenedisalicylic acid under hydrothermal conditions

Reaction of 5,5′‐methylenedisalicylic acid (5,5′‐H₄mdsa) with 4,4′‐bipyridine (4,4′‐bipy) and manganese(II) acetate under hydrothermal conditions led to the unexpected 2:3 binary cocrystal 4,4′‐methylenediphenol–4,4′‐bipyridine (2/3), C₁₃H₁₂O₂·1.5C₁₀H₈N₂ or (4,4′‐H₂dhdp)(4,4′‐bipy)_1.5, which is formed with a concomitant decarboxylation. The asymmetric unit contains one and a half 4,4′‐bipy molecules, one of which straddles a centre of inversion, and one 4,4′‐H₂dhdp molecule. O—H...N interactions between the hydroxy and pyridyl groups lead to a discrete ribbon motif with an unusual 2:3 stoichiometric ratio of strong hydrogen‐bonding donors and acceptors. One of the pyridyl N‐atom donors is not involved in hydrogen‐bond formation. Additional weak C—H...O interactions between 4,4′‐bipy and 4,4′‐H₂dhdp molecules complete a two‐dimensional bilayer supramolecular structure.     

A novel cadmium(II) coordination polymer with biphenyl‐3,3′,4,4′‐tetra­carboxylic acid and 4,4′‐bipyridine

A novel cadmium(II) coordination polymer, poly[[[bis­(4,4′‐bipyridine)cadmium(II)]‐μ₃‐4,4′‐dicarboxy­biphenyl‐3,3′‐di­carboxyl­ato] 0.35‐hydrate], {[Cd(C₁₆H₈O₈)(C₁₀H₈N₂)₂]·0.35H₂O}_n, was obtained by reaction of Cd(CH₃COO)₂·3H₂O, 4,4′‐bipyridine (4,4′‐bpy) and biphenyl‐3,3′,4,4′‐tetra­car­boxylic acid (H₄L) under hydro­thermal conditions. Each Cd^II atom lies at the centre of a distorted octa­hedron, coordinated by four O atoms from three H₂L²⁻ ligands and N atoms from two monodentate 4,4′‐bpy ligands. Each H₂L²⁻ ligand coordinates to three Cd^II atoms through two carboxyl­ate groups, one acting as a bridging bidentate ligand and the other in a chelating bidentate fashion. Two Cd atoms, two H₂L²⁻ anions and four 4,4′‐bpy ligands form a ring dimer node, which links into an extended broad zonal one‐dimensional chain along the c axis.     

3,3′,5,5′‐Tetramethyl‐4,4′‐bipyrazole–pentafluorophenol (2/3)

In the title compound, 2C₁₀H₁₄N₄·3C₆HF₅O, one of the pentafluorophenol molecules resides on a mirror plane bisecting the O...F axis. The components aggregate by N—H...N, N—H...O and O—H...N hydrogen bonds involving equal disordering of the H atoms into molecular ensembles based on a 2:1 pyrazole–phenol cyclic pattern [O...N = 2.7768 (16) Å and N...N = 2.859 (2) Å], crosslinked into one‐dimensional columns via hydrogen bonding between the outer pyrazole groups and additional pentafluorophenol molecules. The latter yields a 1:1 pyrazole–phenol catemer with alternating strong O—H...N [2.5975 (16) Å] and weaker N—H...O [2.8719 (17) Å] hydrogen bonds. This is the first reported molecular adduct of a pentafluorinated phenol and a nitrogen base, and suggests the utility of highly acidic phenols and pyrazoles for developing hydrogen‐bonded cocrystals.     

CEC with tris(2,2′‐bipyridyl) ruthenium(II) electrochemiluminescent detection

For the first time, CEC was coupled with tris(2,2‐bipyridyl) ruthenium(II) ( Ru(bpy) electrochemiluminescence detection. Efficient CEC separations of proline, putrescine, spermidine and spermine were achieved when the pH of the mobile phase is in the range of 3.5–7.0. The optimum mobile phase for CEC separation is much less acidic than that for CZE separation, which matches better with the optimum pH for Ru(bpy) electrochemiluminescence detection and dramatically shortens the analysis time because of larger EOF at higher pH. The time for CEC separation of the polyamines is less than 12.5 min, which is about half as much as the time needed for CZE. The detection limits were 1.7, 0.2, and 0.2 μM for putrescine, spermidine, and spermine, respectively. The RSD of retention time and peak height of these polyamines were less than 0.85 and 6.1%, respectively. The column showed good long‐term stability, and the RSD of retention time is below 5% for 150 runs over one‐month use. The method was successfully used for the determination of polyamines in urine samples.