Complex formation between rhodamine B and poly(sodium 4-styrenesulfonate) studied by 1H-NMR

A 1H NMR study is presented for the binding of rhodamine B (RB) to the polyanion containing aromatic groups poly(sodium 4-styrenesulfonate) (PSS), which is also evidenced by diafiltration. 1H NMR spectra showed an accentuated upfield shift of proton H6' of the benzoic ring of RB at pH 7, indicating the stacking of RB onto PSS. The corresponding structure is proposed which is in accordance to Hunter and Sanders rules. At pH 2, an upfield shift of the xanthene protons of RB would indicate a highly condensed state for this molecule.     

Preparation and application of odorless 1,3-propanedithiol reagents

2-Dodecyl-1,3-propanedithiol (2a) was prepared without a malodorous procedure as an odorless reagent that was usable in place of 1,3-propanedithiol (1) in organic reactions, e.g., in the reduction of azides and protection of carbonyl groups. The 1,3-dithioacetals obtained in the latter reaction were effectively reduced to methylene with Raney nickel and reconverted to the original carbonyl compounds by hydrolysis with N-bromosuccinimide in aqueous 2-butanone. In addition, the anion of 1,3-dithiane prepared from 2a and formaldehyde could be utilized as a synthetic equivalent of an anionic carbonyl carbon.     

Oxygen-Exchange Reaction Between Artificial Lung Device: The Heme Embedded in Polymerized Lipo Liposome as an Artificial Oxygen Carrier

An oxygen-supplying medium (OSM), which was prepared by embedding a synthetic heme complex in a bilayer of polymerized lipid liposome (polylipid liposome/heme), could bind molecular oxygen reversibly under physiological conditions. The oxygen-exchange reaction of OSM with blood was examined by using a liquid/liquid artificial lung device. For example, deoxy-blood (p _s(O₂) = 0 torr) was passed countercurrent to oxy-OSM (p _s(O₂) = 154 torr) through hollow fibers of the device to provide oxy-blood (p _b(O₂) = 57 torr). The OSM was physicochemically and mechanically stable under strong shear stress during the passage through the hollow fibers and acted as the oxygen mediator to blood.     

Facilitated Transport of Molecular Oxygen in Membranes of Macromolecular Cobalt-Porphyrin Complex: Modification of Dual-Mode Transport Model

Transport of molecular oxygen is facilitated in poly(butyl methacrylate) membranes containing the cobalt(II)-α,α′,α″,α′″-meso-tetrakis(o-pivalamidophenyl)porphyrin-1-methylimidazole (CoPIm) complex which forms oxygen adduct rapidly and reversibly. The facilitated transport of oxygen is studied by modifying a dual-mode transport model for gas permeation. The diffusion coefficient of oxygen via the fixed CoPIm complexes (Langmuir mode) is assumed to depend on oxygen concentration, and the modified dual-mode transport equation is described for the permeation steady state. The modified equation represents the effect of upstream oxygen pressure on the permeability. The oxygen permeation behavior through the macromolecular-metal complex membrane is discussed.     

A high-spin and durable polyradical: poly(4-diphenylaminium-1,2-phenylenevinylene)

A purely organic, high-spin, and durable polyradical molecule was synthesized: It is based on the non-Kekulé- and non-disjoint design of a pi-conjugated poly(1,2-phenylenevinylene) backbone pendantly 4-substituted with multiple robust arylaminium radicals. 4-N,N-Bis(4-methoxy- and -tert-butylphenyl)amino-2-bromostyrene 5 were synthesized and polymerized with a palladium-phosphine catalyst to afford the head-to-tail-linked polyradical precursors (1). Oxidation of 1 with the nitrosonium ion solubilized with a crown ether gave the aminium polyradicals (1(+)()) which were durable (half-life > 1 month) at room temperature in air. A high-spin ground state with an average S = (4.5)/2 for 1a(+) was proved even at room temperature by magnetic susceptibility, magnetization, ESR, and NMR measurements.     

Dendron-combined poly(4-diphenyl- aminium-1,2-phenylenevinylene): an isolated multiplet molecule

[structure: see text] Poly[4-(N,N-bis(4-3,5-bis(3,5-bis(benzyloxy)benzyloxy)benzyloxyphenyl)amino)-1,2-phenylenevinylene] was prepared by the palladium-catalyzed polycondensation of the dendron-coupled bromostyrene and oxidized to yield the corresponding poly(aminium cationic radical): The dendron-combined polyradical molecule displayed both a substantial chemical stability and a multiplet state without any intermolecular interaction.     

m-Phenylene-linked aromatic poly(aminium cationic radical)s: persistent high-spin organic polyradicals

[structure: see text] High molecular weight and networked aromatic polyamines prepared by palladium-catalyzed polycondensation were oxidized to yield the corresponding poly(aminium cationic radical)s, which displayed a substantial stability and an intramolecular ferromagnetic interaction of eight or nine spins.