Motivated by the unique chemistry of aluminum cluster anions, studies of their reactions with a model alkene, propene, were conducted in a fast-flow-tube apparatus. Under moderate concentrations of propene, only A1(12)(-) was found to be reactive. At higher propene concentrations, Al-15(-), Al-18(-), and Al-21(-) were also found to react. Electronic structure studies for Al-n(-) (n = 7-14) were carried out using a first principles density functional approach. The results are considered in terms of the empirical rules, recently proposed by Chretien et al. to account for alkene adsorption on metal clusters. Finally, the prospect of exploring further chemistry involving metal cluster additions to alkenes utilizing AlnIx- clusters is considered. (c) 2005 Elsevier B.V. All rights reserved.