Pontes, Ana Cristina Facundo de BritoAnjos, Alexsandro Lima dos2019-01-082019-01-082018-11-01ANJOS, Alexsandro Lima dos. Síntese e caracterização de complexos de molibdênio(VI) com ligantes nitrogenados. 2018. 112f. Dissertação (Mestrado em Química) - Centro de Ciências Exatas e da Terra, Universidade Federal do Rio Grande do Norte, Natal, 2018.https://repositorio.ufrn.br/jspui/handle/123456789/26429Molybdenum is a metal that is present in the human body and performs important functions, such as assisting catalytic redox processes and transfer of oxygen atoms between substrates. In addition, this metal are widely used to obtain new compounds with biological activities or catalysts in epoxidation reactions. Therefore, the present work aims to the synthesis and characterization of cis-dioxomolybdenum(VI) complexes with ligands 1,10-Phenantroline (phen), Azide (N3 - ) and Metformin (met). Thus, the cis-[Mo(phen)(O)2Cl2], cis- [Mo(phen)(O)2(N3)2] and cis- [Mo(met)(O)2Cl2] compounds were obtained from the precursor cis-[Mo(DMSO)2(O)2 Cl2]. The complexes were obtained by adjusting the synthesis conditions as temperature, reaction time and proportion of the precursor with the ligands, for replacement of the DMSO ligands by the phen or metformin and the chlorides by the azides. The characterization was performed using spectroscopic (Infrared, Raman and Uv-vis), electrochemical and thermoanalytical techniques. The vibrational spectra displayed the Mo=O stretch, with bands on 919 and 891 cm-1 for the precursor, 933 and 896 cm-1 for complex with the ligand phen, 915 and 885 cm-1 for azido complex and 947 and 891 cm-1 for complex with metformin, indicating the influence of the nature of ligands in this stretch. In addition to variation in the main absorptions of the other ligands, showing coordination with the metal. The electronic spectra, obtained in water, did not present d-d transitions, the molybdenum is in maximum oxidation state (6+). Only the LMCT bands for chlorines at 213 and 234 nm were verified, in addition to other LMCT at 272 nm for the DMSO. The complexes containing the phenanthroline ligand presented characteristic intraligand bands for the system. Cyclic voltammetry showed a variation of the redox potential of the metal due to the ligand exchange, as observed in the reduction potential of the Mo6+/5+ process at -502 mV for the precursor, -578 mV for cis-[Mo(phen)(O)2Cl2], -589 mV for the azido complex and -600 mV for cis- [Mo(met)(O)2Cl2]. With thermogravimetry it was possible to evaluate the stability of the compounds and the influence of the ligands on the main characteristics of the system, especially the initial decomposition temperature of the complexes formed. Thus, the set of techniques provided a correlation between the donor capacity of the oxo groups and the influence of ligands with different characteristics, showing how the electronic density around the metal can vary.Acesso AbertoMolibdênio(VI)FenantrolinaAzidaMetforminamasterThesisCNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA