Investigation of some transition metal complexes were carried out at room temperature in the new clan of room temperature ionic liquids of choline chloride based composition The Ultraviolet Visible Spectroscopic spectra of Cr3+, Fe3+, Co2+, Ni2+ and Cu2 indicated a complexes formation between the metal ions and the entities of these types of RTILs solvents namely choline chloride/ urea and choline chloride malonic acid which have freezing point at 12o C and 0oC respectively The complexes in choline chloride/ urea were found to be of Octahedral geometry for Cr3+, Ni2+ and Cu2+, and Tetrahedral geometry for Fe3+, Co2+ meta ions. Their spectra were found to be assigned to normal transition state of L corresponding dn configuration in both geometries of Octahedral and Tetrahedral Substitution of solvent coordinated to these metals by added nitrate ions were observed, suggested a weak bonding between solvent molecules and transition metal cations, although they showed some geometrical coordination of corresponding metal cations. All complexes were found to reach final state of coordination at 72 hours, except Co2+ complexes when they showed instability when they were left at room temperature for 40 days In choline chloride/ malonic acid the geometrical coordination of Ni2+ and Cu2+ showed tetrahedral geometry rather than octahedral geometry in this RTIL while the other cations have similar coordination geometry CFT splitting value (10Dq) have been determined for most of new formed complexes using appropriate dn Orgel and Tanabe-Sugano diagrams, and Jorgenson rule was used to asset the suggestion of the type of ligands coordinated to transition metal cations. The nature of the bonding between the metal ions and the donor ligands were demonstrated through the Jorgenson rule and calculation of Racah parameters B̀ were obtained form appropriate dn Tanabe-Sugano diagrams together with the qualitative assistance of Orgel diagrams.
