Among other compounds with weak bonding, the co-ordination molecular complexes are very sensitive both to local modification and external effects such as: substitution via cations having various valence and spin states or anions with different nature, ligands in form of chains or rings or via temperature, pressure and irradiations with particles or gamma rays. The presentation is centered on a peculiar class of iron-oxines (8-quinolines), containing bivalent and trivalent iron, and homologues with various substitutions, as well as on specific attributes and the properties changes of each individual sample subjected to external actions. The local interaction, the bonding adjustments generated by substitutions and their specific configurations or consequences of the selected route of processing are presented in terms of comparative Tables and Graphs. The valence of substitutions clearly determined the molecular packing with direct influence on local interactions. The bivalent complex (Fe2+) has a planar configuration, while when it is present a trivalent ion, the compounds crystallize in octahedral packing with non-symmetrical Fe-N and Fe-O bonds, what will be accordingly emphasized. On the other side the effects of thermal treatment up to compounds decomposition in air or in self-protected (own volatile products) atmosphere revealed modifications of lattice vibration, weaknesses of neighbor bonds and a competition of various phases in the final products. A remarkable result is related to the proof of a rotational process inside molecular 3D structure. Some new or unexpected features, provided by complex and appropriate Mössbauer spectroscopy investigations, will be particularly underlined.