M(C2H2)n+ (M = V, Ag, Au, Zn) ion-molecule complexes are produced in the gas phase via pulsed laser vaporization in a supersonic expansion of acetylene and argon. Cations are size selected and studied via infrared photodissociation spectroscopy in the CH stretching region (28003500 cm-1). Insight into the structure and bonding of these species is obtained from the number of infrared active bands, their relative intensities and their frequency positions. Density functional theory calculations provide structures for these complexes and predicted spectra are compared to the experiment. Studies gold complexes indicated a primary coordination of two with a secondary coordination of three, through cation -bonding. The gold complexes also produce a spectrum at n=6 that indicates the closing a second shell. The studies on silver show a coordination of n=4 with a tetrahedral structure, also through cation -bonding, and no specific type of secondary coordination shell. Both these results are compared to the previously studied copper to get a comparison down the noble metal group. Zinc complexes are studied from n = 15, where we observe the interaction of the acetylene and metal ion to not be through -bonding but a direct metal-carbon interaction via one of the carbons in acetylene. Acetylene deformation is observed with the interaction of the fourth acetylene with the zinc ion with a radical shift from the zinc to the carbon. The vanadium complexes indicate the possibility of intracluster reactions forming benzene at the n=3 complex, which is dependent on the concentration of the acetylene in the argon gas mix. At low concentration of acetylene observations of trapped intermediate are observed in the infrared spectrum.