Nuclear magnetic resonance solvent effects and molecular interactions

Mechanism of alternating copolymerization of acrylic monomers with donor monomers in the presence of lewis acid

“…In the case of the interaction between the coordinated acrylic monomer and the aromatic donor, a specific time-averaged orientation of the benzene ring accounts better for various features of the system as described before:the continuous variation plots using the shifts of various proton groups exhibit a 1 :1 interaction coincidentally; the equilibrium constants for the ternary molecular complex formation determined independently by using the shifts of various protons within the acrylic monomer are in fair agreement with each other; the site factor term for the various proton groups within the acrylic monomer, which causes the shifts for the various proton groups in a specific ratio, is quite different from the site factor term for the time-averaged cluster model (Engler and Laszlo, 1971). The specific time-averaged orientation in the ternary complex model seems to be analogous to the ordering in the collision complex model (Kuntz and Johnston, 1967).…”

Stability of salicylamide-caffeine complex at different temperatures and its thermodynamic parameters

“…Theenthalpy, AH, was obtained from the slope of a plot of log K against 1/T (slope 860) which gives the expected straight line relation, showing that the enthalpy is independent of temperature. This has been proposed as a test for the presence of a single 1 : 1 complex or 1 : 1 isomeric complexes (Orgel & Mulliken, 1957;Kuntz & Johnston, 1967). The linearity observed would seem to justify the simplifications made earlier in data treatment.…”

Polymer swelling. XV. Swelling and deswelling studies of polystyrene–liquid systems in binary solutions

“…(1) ] that would have been exhibited in the absence of such self-association, which occurred in the (Sty),-, (DVB), samples having the lower values of x , is established approximately using only the S,,zdata points recorded for the samples having the higher values of x , i.e., the set of points that fall on the dashed "tangent" line drawn through the common point of intersection on the abscissa ( A l l 3 = 1.76 -t 0.03 = and one or more of the adjacent points, i.e., S,,z at X113 = 2.16,2.38, 2.96, and perhaps 3. 25 ( Figs. 1 and 2 ) .…”