Polymer Blends and Composites in Multiphase Systems I
fWymer Blends
I
and Composite»
if
in Multiphase
•
&CI&iiCG
In any case, electron transfer reac tions in solution obviously are in fluenced by factors other than exothermicity and solvent polarity, the focus of the recent work at Argonne and UC. Further experiments, de signed to explore t h e effects of temperature, distance, and molecu lar geometry, are now under way. Ward Worthy, Chicago
Binuclear copper complex binds oxygen HEW C D . H a n , Editor t Polytechnic Institute of New York Describes new and exciting research activities in polymer blends and com posites. Looks at three aspects of multiphase polymer systems: com patibility and characterization of poly mer blends; rheology, processing, and properties of heterogeneous polymer blends; and polymer com posites. CONTENTS GPC Use in Determination of Polymer-Poly mer Interaction Parameters · Polymer Blend Exhibiting Upper and Lower Critical Solution Temperature Behavior » Phase Equilibria in Polymer Melts by Melt Titration · Comparison of Miscible Blend Binary Interaction Param eters Measured by Different Methods · Com patibility Studies of Poly(vinylidene fluoride): Blends Usina Carbon-13 NMR • Effect of Mo lecular Weight on Blend Miscibility: Study by Excimer Fluorescence · Structure-Property Relationships of Polystyrene/Poly(vinyl methyl ether) Blends · Segmented Orientation in Multicomponent Polymer Systems · Proper ties and Morphology of Poly(methyl methacrylate)/Bisphenol A Polycarbonated Blends · Compatibility of Random Copolymer of Vary ing Composition with Each Homopolymer · Rheological Behavior of Blends of Nylon with Chemically Modified Polyolefin · Controlled Ingredient-Distribution Mixing · Mechanical Behavior of Polyolefin Blends · Model Studies of Rubber Additives in High-Impact Plastics · Reinforcements of Butadiene-Acrylonitrile Elastomer by Carbon Black · Fatigue Crack Propagation in Short-Fiber Reinforced Plas tics · Prediction and Control of Fiber Orienta tion in Molded Parts * Pulling Force and Its Variation in Composite Materials Pultrusion · Effect of Hygrothermal Fatigue on PhysicalMechanical Properties and Morphology of Graphite/Epoxy Laminates
Researchers at the State University of New York, Albany, have prepared, characterized, and for the first time confirmed spectroscopically a syn thetic binuclear copper complex that binds molecular oxygen as perox ide [/. Am. Chem. Soc, 106, 3372 (1984)]. The work represents a step toward better understanding of how copper-containing enzymes bind and activate dioxygen in biological systems. The research was carried out by SUNY associate professor of chemis try Kenneth D. Karlin, postdoctoral fellow Yilma Gultneh, and gradu ate students Richard W. Cruse and Jon C. Hayes. SUNY associate pro fessor of chemistry Jon A. Zubieta collaborated on the cristallograph ie studies. The work was supported by the National Institutes of Health. Such synthetic copper complexes are the focus of current research in many laboratories in the hope that understanding them can help eluci date the activity of a number of
Complex binds oxygen as peroxide +1
Based on a symposium sponsored by the Division of Polymer Chemistry of the American Chemical Society Advances in Chemistry Series 206 286 pages (1984) Clothbound LC 83-24362 ISBN 0-8412-0783-6 US & Canada $59.95 Export $71.95 Order from: American Chemical Society Distribution Office Dept. 01 1155 Sixteenth St., N.W. Washington, DC 20036 or CALL TOLL FREE 800-424-6747 and use your ViSA, MasterCard, or American Express credit card.
44
June 4, 1984 C&EN
^
Ν
Py-/
Ο
Cu*
Ν
Cu*
"Py Note: Py = 2-pyridyl
?
YPy
Py
(Q)
copper-containing enzymes. Hemocyanin, for instance, binds and trans ports oxygen; tyrosinase and dopa mine β-hydroxylase are monooxygenases that incorporate oxygen into organic substrates. Such reactivity also has potential practical applica tion in development of synthetic systems for oxidation reactions. In previous research, Karlin and coworkers prepared a compound that binds two copper ions to form a binuclear copper(I) complex. Each copper ion is coordinated to the three nitrogens of a tridentate ligand consisting of two pyridine groups linked to an aminomethyl nitrogen. The two tridentate groups are linked via the aminomethyls meta to each other on a phenyl ring [/. Am. Chem. Soc, 106, 2121 (1984)]. This complex reacts with dioxygen to form a doubly bridged copper(H) complex with specific hydroxylation of the aromatic ring. Removal of the two copper ions yields a phenol which forms the basis of the recent ly characterized complex. The phenol binds two copper(I) ions to form a new binuclear com plex. That complex reacts w i t h dioxygen. Resonance Raman spec troscopic studies of the complex being carried out by Edward I. Solo mon and coworkers at Stanford Uni versity using isotopically labeled dioxygen confirm that the bound species is peroxide. The orientation of the oxygen atoms cannot yet be determined. Karlin points out that the observed spectrum is not similar to that of oxygen bound to hemocyanin, which suggests that the mode of binding is different. However, he adds, "we have demonstrated for the first time that one can produce a synthetic system in which oxygen is bound as peroxide." "One can make an analogy with work in the 1970s on iron porphy rin systems," Karlin says. "That is, where models were designed to mimic the oxygen binding in hemo globin. It is an important step toward a better understanding of the way oxygen is bound, in this case in copper-containing biologi cal systems, and that will give us insights into the way copper en zymes utilize oxygen for oxidation of organic substrates." Rudy Baum, San Francisco
