Difunctional anionic polymerization initiators from the reaction of butyllithium with trans‐stilbene

Abstract

The reaction between butyllithium and trans-stilbene in benzene solvent yields a mixture of 1,2-diphenylhexyllithium and 1,2,3,4-tetraphenyloctyllithium. These compounds readily disproportionate to 1,2-diphenylhexane, 1,2,3,4-tetraphenyloctane, 1,2-dilithio-1,2diphenylhexane, and 1,2-dilithio-1,2,3,4-tetraphenyloctane. The dilithio compounds are efficient initiators for the anionic polymerization of styrene, yielding polymers with predictable molecular weights and narrow molecular weight distributions, (zw /B, m 1.1). ZUSAMMENFASSUNG: Die Umsetzung von Butyllithium und trans-Stilben in benzolischer Losung ergibt eineMischung von 1,2-Diphenylhexyl-lithium und 1,2,3,4-Tetra-phenyloktyl-lithium. Diese Verbindungen disproportionieren leicht in 1,2- Diphenylhexan, 1,2,3,4-Tetraphenyloktan, 1,2-Dilithium-1,2-diphenylhexan und 1,2-Dilithium-1,2,3,4-tetraphenyloktan. Die Dilithiumverbindungen sind wirksame Katalysatoren fur die anionische Polymerisation von Styrol und liefern Polymere von kontrollierbarem Molekulargewicht und geringer Molekulargewichtsstreuung ( s w / R n w 1,l).

Murex trunculus Haemocyanin

“…It is of great interest to study the functional property of these giant molecules and to try to relate structure and function, especially as many haemocyanins, like haemoglobins, show sigmoidal oxygenbinding curves [2-41. As is well known [5] the binding of multiple ligands to equivalent sites on polymeric acceptor molecules in dynamic dissociation equilibrium can lead to sigmoidal binding curves and it would be surprising if the oxygen-binding behaviour of haemocyanin under a given set of conditions was not related to the conformation and arrangement of the subunits. Much interest has centred on the physical basis for sigmoidal binding curves since this lies a t the heart of our understanding of allosteric effects [6,7]. It has been suggested that the binding of small ligands to a multi-subunit protein will generally result in changes in intersubunit bonding energy.…”

Quarternary structure amplification of protein folding differences observed in ‘native’ platelet factor‐4

“…Furthermore, the overall trends on varying solution conditions hold as originally observed [4,5] supporting the idea that subunit interactions also are generally conserved. A shallower slope of In [D]/[M] or In [T]/[D] versus pH indicates, however, relatively fewer and/or weaker electrostatic interactions [20]. This suggests that although conformational changes are apparently slight, they do perturb spatial orientations of charged side-chains.…”

Synthesis of block polymers by homogeneous anionic polymerization

“…The nucleophilic addition of n-butyllithium to trans-stilbene is normally expected to yield the addition product of 1,2-diphenylhexyllithium. However, when mixed in a ratio of 311 (t-stilbeneIn-CqHgLi) the reaction in benzene a t 65-70°C over a period of 22 hr gave a mixture of 1,2-di- lithio-1,2-diphenylhexane and 1,2-dilithi0-1,2,3,4-tetraphenyloctane (101). No monofunctional organolithium was isolated.…”