A novel binuclear ruthenium complex: spectroscopic and electrochemical characterization, and formation of Langmuir and Langmuir-Blodgett films

Abstract

O complexo [{RuCl 3 (dppb)} 2 (µ-4,4'-bipy)] (dppb = PPh 2 (CH 2 ) 4 PPh 2 ; 4,4'-bipy= 4,4'-bipiridil) foi obtido por meio da reação entre 4,4'-bipiridina e mer- [RuCl 3 (dppb)] . H 2 O, em bom rendimento. As características do complexo binuclear obtido, estudadas por medidas de FT-IR, UV-Vis, EPR e análise elementar foram similares às do complexo [RuCl 3 (dppb)L] (L= N-heterociclo).[{RuCl 3 (dppb)} 2 (µ-4,4'-bipy)] é solúvel em solventes fracamente polares, facilitando a sua utilização para produzir filmes de Langmuir e Langmuir-Blodgett (LB). Enquanto que filmes cast e o complexo em solução são vermelhos, filmes LB são azul-esverdeados, provavelmente devido à oxidação da bisfosfina. A natureza nanoestruturada dos filmes LB, se manifestou nas medidas eletroquímicas, já que estes filmes exibem maior corrente de pico do que os filmes cast e dipcoated. As respostas eletroquímicas destes filmes são caracterizadas pelo processo Ru [{RuCl 3 (dppb)} 2 (µ-4,4'-bipy)] was prepared from the reaction of the 4,4'-bipyridine and mer-[RuCl 3 (dppb)] . H 2 O, in good yield. The characteristics of the binuclear complex studied with FT-IR, UV-Vis, EPR and elemental analysis were similar to those of the [RuCl 3 (dppb)L] (L= Nheterocycle). [{RuCl 3 (dppb)} 2 (µ-4,4'-bipy)] is soluble in weakly polar organic solvents, facilitating its use in the production of Langmuir and Langmuir-Blodgett (LB) films production. While the cast films and the complex in solution were red, the LB films were green-bluish, probably due to oxidation of the bisphosphine. The nanostructured nature of the LB films was manifested in electrochemical measurements, as these films exhibited higher peak currents than cast or dipcoated films. For all films, the electrochemical response was dominated by the Ru III Ru III /Ru II Ru II process, which differed from that of the binuclear compound. For the latter, an irreversible process appeared due to formation of new species. The electroactivity of LB films from [{RuCl 3 (dppb)} 2 (µ-4,4'-bipy)] also pointed to their possible use in electrochemical devices.

Challenges in Application of Langmuir Monolayer Studies To Determine the Mechanisms of Bactericidal Activity of Ruthenium Complexes

“…The collapse pressure was ca. 60 mN/m for both compounds, higher than that for other Ru phosphine complexes. − On the basis of the maximum compressibility modulus, that is, C s –1 max of 91.0 ± 0.2 mN/m for RuBTZ and 77.4 ± 9.4 mN/m for RuCTZ, these films may be classified as liquid-expanded. For RuBTZ, there is no plateau in the π– A isotherm, consistent with the BAM image in Figure B, typical of a film without domains.…”

“…Increasing surface pressure resulted in the coalescence of domains to form a film with a porous appearance, which may be correlated with non-monomolecular structures formed for this inorganic complex. 27 One should remark that condensed domains were observed in spite of the liquidexpanded nature of the film according to the compressibility modulus, as the low value of the latter seems to arise from porous films with non-monomolecular structures.…”

Correlation of [RuCl3(dppb)(VPy)] Cytotoxicity with its Effects on the Cell Membranes: An Investigation Using Langmuir Monolayers as Membrane Models

“…All solvents were purchased from Merck. mer -[RuCl 3 (dppb)(VPy)] was synthesized through a well-established route for similar complexes. , The ligands 1,4-bis(diphenylphosphino)butane (dppb) and 4-vinylpyridine were used as received from Aldrich. The phospholipid with chirality levogero l -dipalmitoylphosphatidylcholine (referred to as DPPC hereafter) and a racemic mixture of the rac-dipalmitoylphosphatidylglycerol (DPPG hereafter) were acquired from Avanti Polar Lipids and used without further purification.…”

Filmes híbridos orgânico-inorgânicos formados pela técnica da automontagem eletrostática camada-por-camada contendo polioxometalatos do tipo Keggin

“…A grande maioria de filmes LB produzidos emprega o uso de moléculas anfifílicas, embora polímeros [15][16], complexos metálicos [17][18] e clusters metal-óxido [19] também sejam usados. Filmes LB têm sido destinados às mais diversas aplicações como em sensores [20], biosensores [21] e em dispositivos ópticos [22] e magnéticos [23].…”