Chirale 2,2′-Polyoxaalkano-9,9′-spirobifluorene

Chiral 2,2′-polyoxaalkano-9,9′-spirobifluorenes From 2,2′-diacetyl-9,9′-spirobifluorene (2) , twelve chiral polyethers have been prepared as potential ion- and enantiomer-selective ionophores. The absolute configuration of the polyethers 15 – 17 , 19 – 22 , and 25 has been determined by chemical correlation with vespirenes [11] [29], by circular dichroism, and by X-ray analysis. The circular dichroism of 15 – 17 , 19 and 21 depends on the size of the macrocycle and indicates that the fluorene chromophores of 19 and 21 with 13- and 16-membered rings respectively deviate considerably from orthogonality.     

Poly(4,4′-dipiperidyl)amides

Polyamides from 4,4′-dipiperidyl, 1,2-ethylene-, and 1,3-propylene- bridged dipiperidyls were prepared via solution and interfacial polycondensation techniques. In sharp contrast to the polyamides from N,N′-alkyl-substituted alkylene diamines and aromatic diacids, the polyamides from 4,4′-dipiperidyls are high-melting (up to 455°C) and alcohol-insoluble. Tough films were cast from formic acid solutions of the polymers; fiber of good physical properties was prepared from a formic acid solution of the polyterephthalamide of 1,2-di(4-piperidyl)ethane.     

Optisch aktive 9,9′-Spirobifluoren-Derivate

The optically active compounds XXIII, XXIV, and XXV, named vespirenes, have been synthetized as first examples of compounds containing a single chirality centre of the type X(A₄). The analogous optically active 9,9′-spirobifluorene derivatives XXI, XXVI, and XXVIII have been prepared for comparison of their chiroptic properties with those of vespirenes.     

2,2′‐Bi(9,9‐di­hexyl­fluorene)

The central part of the title mol­ecule, C₅₀H₆₆, is planar, all the rings being in the same plane; the lateral chains are also planar (excluding H atoms), almost perpendicular to the ring plane and grafted on the same side of the mol­ecule. The mol­ecule has nearly a mirror plane, perpendicular to the central C—C bond, instead of the centre of symmetry expected. The orientation of the plane of the rings is approximately 45° from the unit‐cell b axis, so that neighbouring mol­ecules are essentially perpendicular.     

Novel W(CO)6-Promoted C-S Bond Cleavage Reactions of Dithianes. X-Ray Structure of 9,9′:9,9′-Terfluorene

The reactions of dithianes with W(CO)₆ in refluxing chlorobenzene give dimeric alkenes and their reduced products; fluorenone derivative yielding trimer 8. A radical mechanism is suggested. The structure of 8 has been determined by a single-crystal X-ray diffraction study. Crystal data: P2₁/n; a = 11.948(5), b = 16.8795(14), c = 13.491(6) Å, β = 105.03(3)°, Z = 4, V = 2628(2) ų; R_F = 0.061, R_WF = 0.051 for 2142 reflections and 353 variables.     

2,2′‐Bi(9,9‐di‐n‐propyl­fluorene)

The central part of the title mol­ecule, C₃₈H₄₂, is planar, all the rings being in the same plane; the lateral chains (excluding H atoms) are also planar, with each pair almost perpendicular to the ring plane. In the dimer, the two alkyl‐substituted fluorene moieties are head‐to‐foot. The mol­ecule is on a special position of the space group, a centre of symmetry.     

Poly(3,3′-dimethoxy-2,2′-bithiophene): Synthesis and comparison with poly(3-methoxythiophene)

A new electroactive polymer, namely poly(3,3′-dimethoxy-2,2′-bithiophene) has been prepared by voltammetric polymerization of 3,3′-dimethoxy-2,2′-bithiophene. Due to a different coupling pattern (equivalent to “head-to-head,” and “tail-to-tail” coupled alkoxythiophene rings), poly(3,3′-dimethoxy-2,2′-bithiophene) exhibits different voltammetric properties than the corresponding “head-to-tail” coupled polymer, i.e., poly(3-methoxythiophene). Poly(3,3′-dimethoxy-2,2′-bithiophene) gives very sharp oxidation and reduction peaks indicating an abrupt insulator to conductor transition. This hypothesis was corroborated by the studies of relative resistance as a function of electrode potential. Sharper and better-defined redox peaks may indicate better stereoregularity of poly(3,3′-dimethoxy-2,2′-bithiophene) as compared to poly(3-methoxythiophene) since in this compound the 5,5′-coupling positions are geometrically equivalent and no coupling defects are expected. © 1992 John Wiley & Sons, Inc.     

Synthesis and properties of soluble aromatic polyamides derived from 2,2′‐bis(4‐carboxyphenoxy)‐9,9′‐spirobifluorene

The synthesis of a new bis(ether carboxylic acid), 2,2′‐bis(4‐carboxyphenoxy)‐9,9′‐spirobifluorene, in which two orthogonally arranged carboxyphenoxyfluorene entities are connected through an sp³ carbon atom (the spiro center), is reported. The direct phosphorylation polycondensation of this diacid monomer with various aromatic diamines yields aromatic polyamides containing 9,9′‐spirobifluorene moieties in the main chain. The presence of the spiro segment restricts the close packing of the polymer chains and decreases interchain interactions, resulting in amorphous polyamides with enhanced solubility, and high glass‐transition temperatures and good thermal stability are maintained through controlled segmental mobility. The glass‐transition temperatures of these polyamides are in the range of 234–306 °C, with 10% weight losses occurring at temperatures above 530 °C. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1160–1166, 2003     

Synthesis and characterization of soluble polyimides derived from 2,2′‐Bis(3,4‐dicarboxyphenoxy)‐9,9′‐spirobifluorene dianhydride

The synthesis of aromatic poly(ether imide)s containing spirobifluorene units in the polymer backbone is described. 2,2′‐Bis(3,4‐dicarboxyphenoxy)‐9,9′‐spirobifluorene dianhydride, which was used as a new monomer, was synthesized with 2,2′‐dihydroxy‐9,9′‐spirobifluorene as the starting material. In the spiro‐segment, the rings of the connected bifluorene were orthogonally arranged. This bis(ether anhydride) monomer was employed in reactions with a variety of aromatic diamines to furnish poly(ether imide)s, involving an initial ring‐opening polycondensation and subsequent chemically induced cyclodehydration. Excellent solubility in common organic solvents at room temperature, good optical transparency, and high thermal stability are the prominent characteristic features of these new polymers, which can be attributed to the presence of spiro‐fused orthogonal bifluorene segments along the polymer chain. The glass‐transition temperatures of the polyimides were 240–293 °C, and the 5% weight‐loss temperatures were greater than 500 °C. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 40: 262–268, 2002     

Poly(ethylene terephthalate) reinforced by N,N′‐diphenyl biphenyl‐3,3′,4,4′‐tetracarboxydiimide moieties

Starting with 3,3′,4,4′‐biphenyltetracarboxylic dianhydride and methyl aminobenzoate, we synthesized a novel rodlike imide‐containing monomer, N,N′‐bis[p‐(methoxy carbonyl) phenyl]‐biphenyl‐3,3′,4,4′‐tetracarboxydiimide (BMBI). The polycondensation of BMBI with dimethyl terephthalate and ethylene glycol yielded a series of copoly(ester imide)s based on the BMBI‐modified poly(ethylene terephthalate) (PET) backbone. Compared with PET, these BMBI‐modified polyesters had higher glass‐transition temperatures and higher stiffness and strength. In particular, the poly(ethylene terephthalate imide) PETI‐5, which contained 5 mol % of the imide moieties, had a glass‐transition temperature of 89.9 °C (11 °C higher than the glass‐transition temperature of PET), a tensile modulus of 869.4 MPa (20.2 % higher than that of PET), and a tensile strength of 80.8 MPa (38.8 % higher than that of PET). Therefore, a significant reinforcing effect was observed in these imide‐modified polyesters, and a new approach to higher property polyesters was suggested. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 852–863, 2002; DOI 10.1002/pola.10169     

Formation of nanofibers in Poly(9,9‐dioctylfluorene) toluene solutions during aging

We report the formation of β‐phase nanofibers of poly(9,9‐dioctylfluorene) (PF8) in aged toluene solution at low temperature and link their photophysical properties and rheological behaviors with the solution structures. By cooling the PF8 toluene solution and subsequently aging, the PF8 chains develop into nanofiber morphology and the effects of aging time, temperature, and solution concentration on the nanofiber formation are investigated. The formation and development process of PF8 β‐phase in aged solution captured by TEM has not been reported in previous studies. Further increasing the solution concentration leads to the gelation of PF8 after aging at low temperature. It is interesting to show that a scaling law correlating specific viscosity with the polymer concentration and intrinsic viscosity originally proposed for flexible polymer solutions also exists for this semiflexible PF8 polymer solution. This study may offer an effective way to improve the understanding of the formation mechanism of PF8 β‐phase and facilitate the ongoing exploration of using such nanofiber networks in electronic devices. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 633–639     

Poly(arylene thioether)s containing 9,9′‐spirobifluorene moieties in the main chain: Masked dithiol‐based synthesis and excellent optical properties

Poly(arylene thioether)s ( PTEs ) containing 9,9′‐spirobifluorene moieties were synthesized in high yields from 9,9′‐spirobifluorene‐2,2′‐bis(N,N‐dimethylcarbamothioate) 4 as the masked dithiol and various difluoroarenes as electrophilic monomers. All PTEs showed high thermal stability: The 10% weight loss temperature as evaluated by thermogravimetric analysis was over 470 °C under both nitrogen and air atmospheres. The glass transition temperature estimated by DSC was in the range 210–270 °C. The PTEs showed high solubility in ordinary organic solvents, such as CHCl₃, NMP, and THF. Most PTEs exhibited remarkably high refractive indices ranging from 1.69 to 1.73 at 587.6 nm, whereas no or little birefringence was observed for the PTEs . © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 4192–4199, 2010     

Metallophilic interactions in iodido(2,2′:6′,2′′‐terpyridine)platinum(II) diiodidoaurate(I)

In the title compound, [PtI(C₁₅H₁₁N₃)][AuI₂], the [PtI(terpy)]⁺ cations (terpy is 2,2′:6′,2′′‐terpyridine) stack in pairs about inversion centers through Pt...Pt interactions of 3.5279 (5) Å. The [AuI₂]⁻ anions also exhibit pairwise stacking, with Au...I distances of 3.7713 (5) Å. The [PtI(terpy)]⁺ cations and [AuI₂]⁻ anions aggregate forming infinite arrays of stacked ...({[PtI(terpy)]⁺...[PtI(terpy)]⁺}...{[AuI₂]⁻...[AuI₂]⁻})... units.     

N,N′,N′′,N′′′‐Tetraethylterephthalamidinium bis(tetrazolate)

The crystal structure of the title 2:1 salt of tetrazole and a substituted terephthal­amidine, C₁₆H₂₈N₄²⁺·2CHN₄^?, contains an infinite network of hydrogen bonds, with short N?N distances of 2.820 (2) and 2.8585 (19) Å between the tetrazolate anion and the amidinium cation. Involvement of the lateral N atoms of the tetrazole in the hydrogen bonding appears to be a typical binding pattern for the tetrazolate anion.     

Poly[triaqua(μ4‐4‐carboxybenzenesulfonato‐κ4O:O′:O′′:O′′′)(4‐carboxybenzenesulfonato‐κO)strontium(II)]

This study presents the coordination modes and two‐dimensional network of a novel strontium(II) coordination polymer, [Sr(C₇H₅O₅S)₂(H₂O)₃]_n. The eight‐coordinate Sr²⁺ ion is in a distorted bis‐disphenoidal coordination environment, surrounded by four sulfonate and one carboxyl O atom from five benzenesulfonate ligands, two of which are symmetry unique, and by three O atoms from three independent aqua ligands. The compound exhibits a monolayer structure with coordination bonds within and hydrogen bonds between the layers. The μ₄ acid ligand bridges the metal ions in two dimensions to form a thick undulating monolayer with a hydrophobic interior and hydrophilic surfaces. A second independent monoanion is arranged outward from both sides of the monolayer and serves to link adjacent monolayers via carboxyl–water and water–carboxyl hydrogen bonds.     

Poly(9,9′‐diheylfluorene carbazole) Functionalized with Reduced Graphene Oxide: Convenient Synthesis using Nitrogen‐Based Nucleophiles and Potential Applications in Optical Limiting

Covalently functionalized reduced graphene oxide (RGO) sheet was prepared by treating nitrogen‐centered anions generated from poly(9,9′‐diheylfluorene carbazole) (PCF) with GO. The resultant hybrids with different chemical behavior were separated by centrifugation. The covalent modification was fully characterized by IR spectroscopy, UV/Vis spectroscopy, thermogravimetric analysis (TGA), Raman spectroscopy, TEM, and SEM. It was found that RGO‐PCF‐s, the soluble part, was split into small platelets with a size of about 200 nm, and the hydrophobic polymer PCF became hydrophilic after wrapping by RGO. The content of RGO in RGO‐PCF‐s was about 11.9 %, and the hybrid material showed good dispersion stability in water. Besides, RGO‐PCF‐i, the insoluble part, with larger size, displayed excellent optical‐limiting response, in which both nonlinear absorption and nonlinear scattering play important roles. As nitrogen‐centered anions are an important type of intermediates in chemistry, this one‐step “grafting‐to” strategy could be used to obtain RGO‐based materials with different applications.     

Cobalt(II) and cobalt(III) complexes with 4′‐(4‐cyanophenyl)‐2,2′:6′,2′′‐terpyridine

4′‐Cyanophenyl‐2,2′:6′,2′′‐terpyridine (cptpy) was employed as an N,N′,N′′‐tridentate ligand to synthesize the compounds bis[4′‐(4‐cyanophenyl)‐2,2′:6′,2′′‐terpyridine]cobalt(II) bis(tetrafluoridoborate) nitromethane solvate, [Co^II(C₂₂H₁₄N₄)₂](BF₄)₂·CH₃NO₂, (I), and bis[4′‐(4‐cyanophenyl)‐2,2′:6′,2′′‐terpyridine]cobalt(III) tris(tetrafluoridoborate) nitromethane sesquisolvate, [Co^III(C₂₂H₁₄N₄)₂](BF₄)₃·1.5CH₃NO₂, (II). In both complexes, the cobalt ions occupy a distorted octahedral geometry with two cptpy ligands in a meridional configuration. A greater distortion from octahedral geometry is observed in (I), which indicates a different steric consequence of the constrained ligand bite on the Co^II and Co^III ions. The crystal structure of (I) features an interlocked sheet motif, which differs from the one‐dimensional chain packing style present in (II). The lower dimensionality in (II) can be explained by the disturbance caused by the larger number of anions and solvent molecules involved in the crystal structure of (II). All atoms in (I) are on general positions, and the F atoms of one BF₄⁻ anion are disordered. In (II), one B atom is on an inversion center, necessitating disorder of the four attached F atoms, another B atom is on a twofold axis with ordered F atoms, and the C and N atoms of one nitromethane solvent molecule are on a twofold axis, causing disorder of the methyl H atoms. This relatively uncommon study of analogous Co^II and Co^III complexes provides a better understanding of the effects of different oxidation states on coordination geometry and crystal packing.