Biphenol Units Research Articles

Dramatic Improvement of the Enantiomeric Excess in the Asymmetric Conjugate Addition Reaction Using New Experimental Conditions.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Dramatic improvement of the enantiomeric excess in the asymmetric conjugate addition reaction using new experimental conditions.

The asymmetric conjugate addition of dialkylzincs is usually performed with Cu(OTf)(2) in toluene. We show that by using a copper carboxylate in Et(2)O, THF, or EtOAc, we strongly improve the enantioselectivity with a given ligand. Ee values up to 99.1% could be reached with new ligands based on the induced atropisomerism of a simple biphenol unit. In addition, we show that the Lewis acid effect of Cu(OTf)(2) is not a significant.

3,6,9,16,19,22-Hexaazatricyclo

The adduct (1) formed between the hexaaza macrocycle 3,6,9,16,19,22-hexaazatricyclo[22.2.2.2(11,14]triconta-1(26),11(29),12,14(30),24,27-hexaene, C24H38N6, and 4,4'-sulfonyldiphenol, O2S(C6H4OH)2, is a salt [(C24H40N6)2+].2[(HOC6H4SO2C6H4O)-], and the adduct (2) formed by the same macrocyclic amine with 4,4'-biphenol is an aquated salt which also contains neutral biphenol molecules, [(C24H40N6)2+]. 2[(HOC6H4C6H4O)-].(HOC6H4C6H4OH).2H2O. In both compounds the cations lie across centres of inversion: there are two crystallographically distinct cation sites in (1) and the conformations of the cations occupying them are quite different. In (2) the single type of cation site is occupied by a conformationally disordered cation: the major and minor components represent two further distinct conformers. In (1) the anions are linked by O-H...O hydrogen bonds into chains, and each cation is linked by a total of six N-H...O hydrogen bonds to anions in four different chains, so linking the chains into continuous sheets. In (2) the anions and the water molecules are linked into sheets, which are further linked into a continuous three-dimensional framework by both the cations and the neutral biphenol units.

Meso-5,5,7,12,12,14-Hexamethyl-1,4,8,11-tetraazacyclotetradecane as a building block in supramolecular chemistry; salts formed with 2,2-biphenol, 4,4-thiodiphenol, 4,4-sulfonyldiphenol, 3-and 4-hydroxybenzoic acids, 3,5-dihydroxybenzoic acid and phenylphosphonic acid; supramolecular structures in zero, one, two and three dimensions

The structure of meso-5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane-2,2'-biphenol (1/2), (C16H36N4).(C12H10O2)2 (1), is a salt [C16H38N4]2+.2[HOC6H4C6H4O]-: the cations are centrosymmetric with two protons held within the N4 cavity of the macrocycle by N-H...N hydrogen bonds, and the phenolate anions contain intramolecular O-H...O-hydrogen bonds. The ions are linked into a finite centrosymmetric aggregate by means of N-H...O hydrogen bonds. meso-5,5,7,12,12,14-Hexamethyl-1,4,8,11-tetraazacyclotetradecane-4,4'-thiobiphenol-methanol (1/2/2), (C16H36N4).(C12H10O2S)2.(CH4O)2 (2), and meso-5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane-4,4'-sulfonylbiphenol-methanol (1/2/2), (C16H36N4).(C12H10O4S)2.(CH4O)2 (3), are isomorphous: each is a salt, [C16H38N4]2+.2[HOC6H4SC6H4O]-.2MeOH (2) and [C16H38N4]2+.2[HOC6H4SO2C6H4O]-.2MeOH (3), and in each the phenolate anions are linked by O-H...O- hydrogen bonds into chains; antiparallel pairs of chains are cross-linked by the cations to form molecular ladders, with neutral methanol molecules acting as spacer units. In meso-5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane-3-hydroxybenzoic acid-methanol (1/2/2) (4), 3-hydroxybenzoate anions form chains, again cross-linked in pairs by the [C16H38N4]2+ cations to form molecular ladders, different from those in (2) and (3) in that the neutral methanol units are pendent from the ladders, rather than forming a part of it. meso-5,5,7,12,12,14-Hexamethyl-1,4,8,11-tetraazacyclotetradecane-4-hydroxybenzoic acid-methanol (1/2/1) (5) is again a salt, [C16H38N4]2+.2[HOC6H4COO]-.MeOH: chains of 4-hydroxybenzoate anions are continuously cross-linked by two different types of [C16H38N4]2+ cation into a two-dimensional net. Only one of the two types of cation is linked to the chains via neutral methanol spacer units. meso-5,5,7,12,12,14-Hexamethyl-1,4,8,11-tetraazacyclotetradecane-phenylphosphonic acid-water (1/4/2) (6) is a salt, [C16H40N4]4+.4[C6H5PO3H]-.2H2O, containing the centrosymmetric tetraprotonated amine units, which have a conformation quite different from the trans-III conformation uniformly found in the [C16H38N4]2+ cations. The phenylphosphonate anions and the water molecules are linked into chains of fused rings, which are linked by the cations into two-dimensional nets. In meso-5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetrade cane-3,5-dihydroxybenzoic acid (1/2) (7), the 3,5-dihydroxybenzoate anions in the unsolvated salt [C16H38N4]2+.2[(HO)2C6H3COO]- are linked into continuous two-dimensional nets, which are in turn linked by the centrosymmetric cations to form a three-dimensional framework. meso-5,5,7,12,12,14-Hexamethyl-1,4,8,11-tetraazacyclo tetradecane-4,4'-biphenol (1/3) (8) is a salt containing both neutral and anionic biphenol units, [C16H38N4]2+.2[HOC6H4-C6H4O]-.[HOC6H4C6H4OH]. The two types of biphenol unit form two-dimensional nets and these nets are linked by the cations to form three independent, three-dimensional frameworks which are fully interwoven, but not bonded to one another.

2,2'-Biphenol–1,4-diazabicyclo[2.2.2]octane (2/1), a three-dimensional framework built from O—H...O, O—H...N, N—H...O and C—H...π(arene) hydrogen bonds

In the 2:1 adduct of 2,2'-biphenol and 1,4-diazabicyclo[2.2.2]octane, 2C 12 H 10 O 2 .C 6 H 12 N 2 , there are eight molecules of the biphenol and four molecules of the amine in the asymmetric unit, and several of these components exhibit orientational disorder even at 100 K. Each biphenol unit contains an intramolecular O-H...O hydrogen bond [O...O range for the ordered components 2.594(6) to 2.668(5) A]. Each of the amines is hydrogen bonded to two biphenol units [O...N range for the ordered components 2.521(7) to 2.594 (6) A], so forming four independent three-molecule aggregates. These aggregates are further linked by an extensive series of C-H π(arene) interactions into a continuous three-dimensional framework.

Formation of One-Dimensional Chains, Two-Dimensional Bilayers and a Three-Dimensional Diamondoid Architecture in Hydrogen-Bonded Adducts of 4,4'-Biphenol with 1,4-Diazabicyclo[2.2.2]octane and 1,2-Diaminoethane

In 4,4′-biphenol–1,4-diazabicyclo[2.2.2]octane (1/1), C12H10O2.C6H12N2 (1), monoclinic, C2/c, a = 12.1510 (9), b = 6.3202 (4), c = 21.051 (2) Å, β = 98.875 (10)° with Z = 4, the biphenol units lie across twofold rotation axes and the diamine units are disordered across centres of inversion. The molecular components are linked by means of O—H...N hydrogen bonds into zigzag chains with graph set C^{2}_{2}(16) running parallel to the [201] direction; the chains are not coiled and there are no interactions between neighbouring chains. In 4,4′-biphenol–1,2-diaminoethane–methanol (2/1/1), (C12H10O2)2.C2H8N2.CH4O (2), triclinic, P1¯, a = 9.4592 (7), b = 10.6311 (10), c = 12.2085 (14) Å, α = 91.812 (9), β = 93.091 (6), γ = 90.652 (6)° with Z = 2, there are seven independent hydrogen bonds of O—H...O, O—H...N and N—H...O types and each oxygen and each nitrogen acts as a single donor and single acceptor of hydrogen bonds. The four independent components are linked by means of O—H...O and O—H...N hydrogen bonds into a linear aggregate, and further O—H...N and O—H...O hydrogen bonds generate chains in the [011] direction containing alternating biphenol and diamine units, and in the [021] direction containing methanol and pairs of biphenol molecules. These two types of chain intersect to form a continuous two-dimensional net, graph set R^{10}_{10}(62), with biphenol molecules at the nodes: pairs of these nets are linked into bilayers by N—H...O hydrogen bonds, but the nets are not interwoven. In 4,4′-biphenol–1,2-diaminoethane (1/1), C12H10O2.C2H8N2 (3), monoclinic, P21/a, a = 8.2121 (5), b = 5.3401 (3), c = 14.6014 (9) Å, β = 99.962 (7)° with Z = 2, each of the components lies across a centre of inversion. The O atoms act as single donors and double acceptors of hydrogen bonds and the N atoms as double donors and single acceptors, so that both oxygen and nitrogen are effectively four-coordinate; all the hydrogen bonds are of O—H...N or N—H...O type. Chains built from N—H...O and O—H...N hydrogen bonds run parallel to [100] and [010] and the intersection of these gives two-dimensional nets built from R^{6}_{6}(12) rings: these nets are linked by the —C6H4C6H4— and —CH2CH2— spacer units into a continuous three-dimensional diamondoid structure.

Modification of Crystallization Properties of Poly(ethylene terephthalate) by Copolymerization with Arylate Units. 1. Preparation and Isothermal Crystallization of 4,4'-Biphenol-Containing Copolymers

Crystallization properties of the copolymers of poly(ethylene terephthalate) (PET) comprised of a small amount of 4,4'-biphenol units were compared by isothermal crystallization with the time-resolved light scattering method. These copolyesters were prepared from PET, terephthalic acid, and 4,4'-biphenol diacetate by acidolysis reaction and following polycondensation. The copolymer with 2 mol % of 4,4'-biphenol had a crystallization characteristic similar to that of PET with a decreased crystallization rate. On the other hand, the copolymers containing 4 and 8 mol % of 4,4'-biphenol showed enhanced crystal nucleation, and the 8 mol % copolymer had a crystallization rate of ca. twice as fast as that of PET. In these systems, wide-angle X-ray diffraction peaks of the crystal which appeared with crystallization were similar to those of PET, though another ordered domain was observed in the 8 mol % copolymer, which seems to have no direct influence on the crystallization and melting cycle.

Applications of fourier transform infrared microspectroscopy to the analysis of microscopic orientation in liquid crystalline polymer sheets

Fourier transform infrared ( FTi.r.) microspectroscopy was applied to evaluate the microscopic orientation of extrusion moulded sheets of a thermotropic liquid crystalline polymer, consisting of 4-hydroxybenzoic acid units, biphenol units and benzene dicarboxylic acid units. The polarized i.r. spectra were measured in the microscopic area down to 40 μm using a redundantly apertured i.r. microscope equipped with a wire-grid polarizer. It was shown that Beer's law held in the absorbance range below 2.5, and the polarization properties of oriented samples were accurately measured by FTi.r. microspectroscopy. The orientation profiles of the polymer sheets were obtained by plotting the dichroic ratio of the 1602 cm −1 band against distance from the centres of sheets. In the case of the sheet 0.68 mm thick, the central region is nearly isotropic, but the dichroic ratio increases markedly toward the surface of the sheet. In the thinner sheet (0.255 mm), the polymer chains in both surface and central regions are highly oriented in the extrusion direction, and the dichroic ratio gradually increases on approaching the surface. At the same sheet thickness, the degree of orientation decreases as the extrusion temperature is lowered. The orientation profiles obtained by polarized FTi.r. microspectroscopy are in accordance with the morphological structures studied by scanning electron microscopy.

Radiation degradation of statistical terpolymers of two aromatic diols with diphenyl sulphone

AbstractThe variation in radiation resistance with composition of statistical terpolymers of (1) bisphenol‐A and biphenol, and (2) hydroquinone and biphenol, with diphenyl sulphone was studied by electron spin resonance spectroscopy after γ irradiation at 77 K and by analysing volatile products after irradiation at 423 K. Approximately linear relationships were obtained between the radiation chemical yields for both radicals, G(R), and sulphur dioxide, G(SO2), and the mole fraction of biphenol units in the terpolymers. Substantially higher radiation resistance was shown by biphenol units compared with either bisphenol‐A or hydroquinone.