Novembro 2015 vol. 3 num. 1 - 5º Encontro Regional de Química & 4º Encontro Nacional de Química

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Nitro complexos de ferro(III) com derivados da base de Schiff Salen

Iron(III) nitro complexes with Schiff base salen derivatives

PAIVA, Anallicy Santos de ; SILVA, Francisco Ordelei Nascimento da ; PONTES, Ana Cristina Facundo de Brito ; PONTES, Daniel de Lima ;

Completo:

Os complexos com a base de Schiff salen apresentam relevantes aplicações como agentes quimioterápicos e na química de materiais. Buscando desenvolver compostos de coordenação que intensifiquem as propriedades farmacológicas dos complexos contendo bases de Schiff, utilizou-se o íon nitrito para acentuar a atividade biológica devido as características dos nitro complexos de atuarem como pró-droga para a liberação de óxido nítrico em meio biológico, um importante agente de proteção celular e vasodilatador. No presente trabalho foram obtidos novos nitro complexos de ferro(III) com bases de Schiff derivados do salen, sendo sintetizados os ligantes 3-MeOsalen e o 3-MeOsalophen a partir das diaminas etilenodiamina e orto-fenilenodiamina, respectivamente e o aldeído a partir da orto-vanilina em ambos os ligantes. Os compostos 3-MeOsalen e 3-MeOsalophen e os complexos [Fe(3-MeOsalen)Cl], [Fe(3-MeOsalophen)Cl], [Fe(3-MeOsalen)NO2] e [Fe(3-MeOsalophen)NO2] foram caracterizados através da espectroscopia vibracional na região do infravermelho e a espectroscopia eletrônica na região do ultravioleta e visível. A partir da análise dos espectros de infravermelho, foi possível caracterizar os ligantes 3-MeOsalen e 3-MeOsalophen, principalmente, pela presença da banda referente ao C=N próximo a 1620 cm-1. A formação dos complexos precursores foi evidenciada pelas alterações nas frequências de vibração C=N e C-O e pelo surgimento de modos vibracionais metal-oxigênio e metal-nitrogênio. Para os nitro complexos de ferro foram exibidos os (NO2)ass em torno de 1300 cm-1 e (NO2)sim em 1271 cm-1, além da deformação angular em torno de 830 cm-1, indicando que a coordenação do íon nitrito ocorreu via átomo de nitrogênio. Os espectros eletrônicos das bases de Schiff são marcadas pela presença das transições -* do anel aromático e do grupo imino, além da banda n-* referente as transições dos elétrons não ligantes. Os espectros dos complexos precursores [Fe(3-MeOsalen)Cl] e [Fe(3MeOsalophen)Cl] apresentaram deslocamentos das bandas de transições intraligantes e ainda novas bandas referentes a LMCT (pCl-d*Fe3+). Já nos espectros dos compostos [Fe(3-MeOsalen)NO2] e [Fe(3-MeOsalophen)NO2] destacaram-se a ausência da banda LMCT presente no complexo precursor.

Completo:

The iron(III) complexes with Schiff base salen present relevant applications such as chemotherapeutic agents and materials chemistry. Seeking to develop Schiff base coordination compounds with improved pharmacologics properties it was used nitrite ion as ligand due nitro complex usually act as pro-drug releasing nitric oxide in biological environment, an important cell protection agent and vasodilator. In this study were obtained new iron(III) nitro complexes of ligands derivatives from salen Schiff bases, being synthesized ligands 3-MeOsalen and 3-MeOsalophen from ethylenediamine and ortho-phenylenediamine, respectively, and the aldehyde ortho-vanillin. The ligands 3-MeOsalen and 3-MeOsalophen and complexes [Fe(3MeOsalen)Cl], [Fe(3-MeOsalophen)Cl], [Fe(3-MeOsalen)NO2] and [Fe(3-MeOsalophen)NO2] were synthetized and characterized by vibrational spectroscopy in the infrared region and electronic spectroscopy in the ultraviolet and visible region. The infrared spectra allowed the characterization of the ligands 3-MeOsalen and 3-MeOsalophen, mostly by the presence of C=N near 1620 cm-1. The synthesis of the precursor complexes as evidenced by changes in the vibrational frequencies of C=N, C-O and the presence of metal-oxygen and metal-nitrogen vibrational modes. The iron nitro complexes exhibited (NO2)ass around 1300 cm-1 and (NO2)sim at 1271 cm-1 and angular deformation around 830 cm-1, indicating so that the coordination is done via the nitrogen atom. Electronic spectra of the Schiff bases were marked by the presence of -* electronic transitions from aromatic ring and imino group and n-* transitions related to free-electron pairs. For the complexes [Fe(3-MeOsalen)Cl] and [Fe(3-MeOsalophen)Cl] was evidenced shifts of intraligands transitions and the emergence of new bands such as LMCT (pCl-  d*Fe3+). Such charge transfer were not observed in the spectra of [Fe(3-MeOsalen)NO2] and [Fe(3-MeOsalophen)NO2] indicating so the chloride ligand replacement by nitrite ion.

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Palavras-chave: Complexos; base de schiff; salen; nitro.,

Palavras-chave: Complex; Schiff base; salen; nitro,

DOI: 10.5151/chenpro-5erq-in4

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Como citar:

PAIVA, Anallicy Santos de; SILVA, Francisco Ordelei Nascimento da; PONTES, Ana Cristina Facundo de Brito; PONTES, Daniel de Lima; "Nitro complexos de ferro(III) com derivados da base de Schiff Salen", p. 419-427 . In: Anais do V Encontro Regional de Química & IV Encontro Nacional de Química [=Blucher Chemistry Proceedings].. São Paulo: Blucher, 2015.
ISSN 2318-4043, DOI 10.5151/chenpro-5erq-in4

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