TY - JOUR
T1 - Mechanism of Ultrasound Scission of a Silver-Carbene Coordination Polymer
AU - Rooze, J.
AU - Groote, R.
AU - Jakobs, R.T.M.
AU - Sijbesma, R.P.
AU - Iersel, van, M.M.
AU - Rebrov, E.
AU - Schouten, J.C.
AU - Keurentjes, J.T.F.
PY - 2011
Y1 - 2011
N2 - Scission of a supramolecular polymer??metal complex can be carried out using collapsing cavitation bubbles created by ultrasound. Although the most plausible scission mechanism of the coordinative bonds is through mechanical force, the influence of radicals and high hot-spot temperatures on scission has to be considered. A silver(I)??N-heterocyclic carbene complex was exposed to 20 kHz ultrasound in argon, nitrogen, methane, and isobutane saturated toluene. Scission percentages were almost equal under argon, nitrogen, and methane. Radical production differs by a factor of 10 under
these gases, indicating that radical production is not a significant contributor to the scission process. A model to describe the displacement of the bubble wall, strain rates, and temperature in the gas shows that critical strain rates for coil-to-stretch transition, needed for scission, are achieved at reactor temperatures of 298 K, an acoustic pressure of 1.2??105 Pa, and an acoustic frequency of
20 kHz. Lower scission percentages were measured under isobutane, which also shows lower strain rates in model simulations. The activation of the polymer??metal complexes in toluene under the influence of ultrasound occurs through mechanical force.
AB - Scission of a supramolecular polymer??metal complex can be carried out using collapsing cavitation bubbles created by ultrasound. Although the most plausible scission mechanism of the coordinative bonds is through mechanical force, the influence of radicals and high hot-spot temperatures on scission has to be considered. A silver(I)??N-heterocyclic carbene complex was exposed to 20 kHz ultrasound in argon, nitrogen, methane, and isobutane saturated toluene. Scission percentages were almost equal under argon, nitrogen, and methane. Radical production differs by a factor of 10 under
these gases, indicating that radical production is not a significant contributor to the scission process. A model to describe the displacement of the bubble wall, strain rates, and temperature in the gas shows that critical strain rates for coil-to-stretch transition, needed for scission, are achieved at reactor temperatures of 298 K, an acoustic pressure of 1.2??105 Pa, and an acoustic frequency of
20 kHz. Lower scission percentages were measured under isobutane, which also shows lower strain rates in model simulations. The activation of the polymer??metal complexes in toluene under the influence of ultrasound occurs through mechanical force.
U2 - 10.1021/jp203780a
DO - 10.1021/jp203780a
M3 - Article
C2 - 21827184
SN - 1520-6106
VL - 115
SP - 11038
EP - 11043
JO - Journal of Physical Chemistry B
JF - Journal of Physical Chemistry B
IS - 38
ER -