TY - JOUR
T1 - Reactivity of Monolayer Protected Silver Clusters Towards Excess Ligand: A Calorimetric Study
AU - Baksi, Ananya
AU - Bootharaju, Megalamane Siddaramappa
AU - Chhotaray, Pratap K.
AU - Chakraborty, Papri
AU - Mondal, Biswajit
AU - Bhat, Shridevi
AU - Gardas, Ramesh L.
AU - Pradeep, Thalappil
N1 - KAUST Repository Item: Exported on 2020-10-01
Acknowledgements: A.B. and T.P. thank the Department of Science and Technology, Government of India for continuous support our of research program on nanomaterials. A.B. thanks Indian Institute of Technology Madras for fellowship.
PY - 2017/11/16
Y1 - 2017/11/16
N2 - Reactivity of monolayer protected atomically precise clusters of noble metals is of significant research interest. Till date very few experimental data are available on the reaction thermodynamics of such clusters. Here we report a calorimetric study of the reaction of glutathione (GSH) protected silver clusters in presence of excess ligand, GSH using isothermal titration calorimetry (ITC). We have studied Ag11(SG)7 and Ag32(SG)19 clusters and compared their reactivity with GSH protected silver nanoparticles (AgNPs) and silver ions. Clusters show intermediate reactivity towards excess ligand com-pared to nanoparticles and silver ions. Several control experiments were performed to understand the degradation mech-anism of these silver clusters and nanoparticles. Effect of dissolved oxygen in the degradation process was studied in de-tail and found that it did not have a significant role, although alternate pathways of degradation with the involvement of oxygen cannot be ruled out. Direct confirmation of the fact that functionalized metal clusters fall in-between NPs and atomic systems in their stability is obtained experimentally for the first time. Several other thermophysical parameters of these clusters were also determined including, density, speed of sound, isentropic compressibility and coefficient of thermal expansion.
AB - Reactivity of monolayer protected atomically precise clusters of noble metals is of significant research interest. Till date very few experimental data are available on the reaction thermodynamics of such clusters. Here we report a calorimetric study of the reaction of glutathione (GSH) protected silver clusters in presence of excess ligand, GSH using isothermal titration calorimetry (ITC). We have studied Ag11(SG)7 and Ag32(SG)19 clusters and compared their reactivity with GSH protected silver nanoparticles (AgNPs) and silver ions. Clusters show intermediate reactivity towards excess ligand com-pared to nanoparticles and silver ions. Several control experiments were performed to understand the degradation mech-anism of these silver clusters and nanoparticles. Effect of dissolved oxygen in the degradation process was studied in de-tail and found that it did not have a significant role, although alternate pathways of degradation with the involvement of oxygen cannot be ruled out. Direct confirmation of the fact that functionalized metal clusters fall in-between NPs and atomic systems in their stability is obtained experimentally for the first time. Several other thermophysical parameters of these clusters were also determined including, density, speed of sound, isentropic compressibility and coefficient of thermal expansion.
UR - http://hdl.handle.net/10754/626133
UR - http://pubs.acs.org/doi/abs/10.1021/acs.jpcc.7b07557
UR - http://www.scopus.com/inward/record.url?scp=85037141607&partnerID=8YFLogxK
U2 - 10.1021/acs.jpcc.7b07557
DO - 10.1021/acs.jpcc.7b07557
M3 - Article
SN - 1932-7447
VL - 121
SP - 26483
EP - 26492
JO - The Journal of Physical Chemistry C
JF - The Journal of Physical Chemistry C
IS - 47
ER -