Because of the interest attached to compounds based on group 13 elements for their energetic and ecological properties and given the poor reputation of the hydrocarbons on the environment degradation, we examine in this work whether an A(x)C(y)H(8) combination (A = group 13 element, x y = 5), could be more optimal in energy and CO2 emission during the hydrogenation and oxidation processes. Starting from pentadiene C5H8 and pure A(5)H(8) (A = B, Al, and Ga) clusters we energetically analyzed C replacement by A (so called metalation) in pentadiene and A replacement C (so called carbonation) in the A(5)H(8) clusters. Moreover, since the release of industrial carbon dioxide is an increasing threat to the environment, compounds which capture and treat CO2 are urgently needed now. However, CO2 treatment and capture requires an energy cost that must be considered in any economic assessment. The CO2 reduction to Methanol CH3OH, widely studied seems to be the perfect way for its recycling but it is not energetically free. That is, the reaction needs to be activated by heating for example. Atomic hydrogen involved in this process also requires an energy input to be produced from natural hydrogen which is in molecular form (H-2). Taking all these processes into account, the pure hydrogenated A(5)H(8) cluster composed of group 13 elements seems to be favored for low CO2 release. (C) 2016 Hydrogen Energy Publications LLC. Published,by Elsevier Ltd. All rights reserved.