Reactive Landing of Dendrimer Ions onto Activated Self-assembled Monolayer Surfaces

Journal Article · Thu Feb 06 04:00:00 EST 2014 · Journal of Physical Chemistry C, 118(5):2602-2608

DOI:https://doi.org/10.1021/jp411637w· OSTI ID:1126324

Hu, Qichi; Laskin, Julia

The reactivity of gaseous, amine-terminated polyamidoamine (PAMAM) dendrimer ions with activated self-assembled monolayer (SAM) surfaces terminated with N-hydroxysuccinimidyl ester groups (NHS-SAM) is examined using mass-selected ion deposition combined with in situ infrared reflection absorption spectroscopy (IRRAS). The reaction extent is determined from depletion of the infrared band at 1753 cm-1, corresponding to the stretching vibration of the NHS carbonyl groups following ion deposition. For reaction yields below 10%, NHS band depletion follows a linear dependence on the ion dose. By comparing the kinetics plots obtained for 1,12-dodecanediamine and different generations of dendrimer ions (G0–G3) containing 4, 8, 16, and 32 terminal amino group, we demonstrate that the relative reaction efficiency increases linearly with the number of NH2 groups in the molecule. This finding is rationalized assuming the formation of multiple amide bonds upon collision of higher-generation dendrimers with NHS-SAM. Furthermore, by comparing the NHS band depletion following deposition of [M+4H]4+ ions of the G2 dendrimer at 30, 80, and 120 eV, we demonstrate that the ion’s kinetic energy has no measurable effect on reaction efficiency. Similarly, the ion’s charge state only has a minor effect on the reactive landing efficiency of dendrimer ions. Our results indicate that reactive landing is an efficient approach for highly selective covalent immobilization of complex multifunctional molecules onto organic surfaces terminated with labile functional groups.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1126324
• Report Number(s): PNNL-SA-99505; 39717; 44660; KC0302020
• Journal Information: Journal of Physical Chemistry C, 118(5):2602-2608, Journal Name: Journal of Physical Chemistry C, 118(5):2602-2608
• Country of Publication: United States
• Language: English

Related Subjects

Environmental Molecular Sciences Laboratory
NHS-SAM surface
Polyamidoamine (PAMAM) dendrimers
grazing incidence
infrared reflection absorption spectroscopy (IRRAS)
ion-surface collisions
reactive landing
self-assembled monolayer (SAM)
soft landing