Photodissociation of the complex between protonated tryptamine, TryH(+), and 18-crown-6 ether (CE) was investigated. Absorption maxima of TryH(+) and TryH(+)(CE) are at 249 and 273 nm, respectively. Ions decay exponentially on a microsecond timescale, and mass spectra reveal that NH3 loss is an important channel even though CE targets this group. TD-DFT calculations identified an electronically excited state, where the photoactive electron is located in an antibonding orbital between C and NH3. Dissociation along this coordinate and CE rearrangement to the new charge site accounts for ammonia loss. Photodissociation in an electric field and time-of-flight measurements corroborate such a non-statistical bond-breakage. (C) 2009 Elsevier B.V. All rights reserved.