84027-71-4Relevant academic research and scientific papers
Attachment of a RuII Complex to a Self-Folding Hexaamide Deep Cavitand
Korom, Sa?a,Ballester, Pablo
supporting information, p. 12109 - 12112 (2017/09/12)
We report the design, synthesis and characterization of a new RuII metallocavitand that is catalytically active in alkene epoxidation reactions. The elaboration of the resorcin[4]arene's aromatic cavity produced a self-folding, deep hexaamide cavitand featuring a single diverging terpyridine (tpy) group installed at its upper rim. The construction of the metallocavitand involved the initial chelation of a RuIII chloride complex by the tpy ligand followed by the incorporation of 2-(phenylazo)pyridine (azpy) as an ancillary ligand. The resulting RuII chloro complex was converted into the catalytically active aqua counterpart by a ligand exchange process.
Coordination of 9-ethylguanine to the mixed-ligand compound α-[Ru(azpy)(bpy)Cl2 (azpy = 2-phenylazopyridine and bpy = 2,2′-bipyridine). An unprecedented ligand positional shift, correlated to the cytotoxicity of this type of [RuL2Cl2] (with L = azpy or bpy) complex
Hotze, Anna C. G.,Van Der Geer, Erwin P. L.,Caspers, Sabrine E.,Kooijman, Huub,Spek, Anthony L.,Haasnoot, Jaap G.,Reedijk, Jan
, p. 4935 - 4943 (2008/10/09)
The striking difference in cytotoxic activity between the inactive cis-[Ru(bpy)2Cl2 and the recently reported highly cytotoxic α-[Ru(azpy)2Cl2 (α indicating the isomer in which the coordinating Cl atoms, pyridine nitrogens, and azo nitrogens are in mutual cis, trans, cis orientation) encouraged the synthesis of the mixed-ligand compound cis-[Ru(azpy)(bpy)Cl2]. The synthesis and characterization of the only occurring isomer, i.e., α-[Ru(azpy)(bpy) Cl2], 1 α denoting the isomer in which the Cl ligands are cis related to each other and the pyridine ring of azpy is trans to the pyridine ring of bpy), are described. The solid-state structure of 1 has been determined by X-ray structure analysis. The IC50 values obtained for several human tumor cell lines have indicated that compound 1 shows mostly a low to moderate cytotoxicity. The binding of the DNA model base 9-ethylguanine (9-EtGua) to the hydrolyzed species of 1 has been studied and compared to DNA model base binding studies of cis-[Ru(bpy)2Cl2] and α-[Ru(azpy)2Cl2]. The completely hydrolyzed species of 1, i.e., α-[Ru(azpy)(bpy)(H2O)2]2+, has been reacted with 9-EtGua in water at room temperature for 24 h. This resulted in the monofunctional binding of only one 9-EtGua, coordinated via the N7 atom. The product has been isolated as α-[Ru(azpy)(bpy)(9-EtGua)(H 2O)](PF6)2, 2, and characterized by 2D NOESY NMR spectroscopy. The NOE data show that the 9-EtGua coordinates (under these conditions) at the position trans to the azo nitrogen atom. Surprisingly, time-dependent 1H NMR data of the 9-EtGua adduct 2 in acetone-d 6 show an unprecedented positional shift of the 9-EtGua from the position trans to the azo nitrogen to the position trans to the bpy nitrogen atom, resulting in the adduct α′-[Ru(azpy)(bpy)(9-EtGua)(H 2O)]-(PF6)2 (α′ indicating 9-EtGua is trans to the bpy nitrogen). This positional isomerization of 9-EtGua is correlated to the cytotoxicity of 1 in comparison to both the cytotoxicity and 9-EtGua coordination of cis-[Ru(bpy)2Cl2], α-[Ru(azpy)2Cl2], and β-[Ru(azpy) 2Cl2]. This positional isomerization process is unprecedented in model base metal chemistry and could be of considerable biological significance.
Dichlorobis(2-phenylazopyridine)ruthenium(II) complexes: characterisation, spectroscopic and structural properties of four isomers.
Velders, Aldrik H,van der Schilden, Karlijn,Hotze, Anna C G,Reedijk, Jan,Kooijman, Huub,Spek, Anthony L
, p. 448 - 455 (2007/10/03)
The didentate ligand 2-phenylazopyridine (azpy) can--in theory--give rise to five different isomeric complexes of the type [Ru(azpy)2Cl2], of which three have been known since 1980. The molecular structures of the cis-dichlorobis(2-phenylazopyridine) ruthenium(II) complexes alpha-[Ru(azpy)2Cl2] and beta-[Ru(azpy)2Cl2](in which the coordinating pyridine nitrogen atoms are in mutually trans and cis positions, respectively, whilst the azo nitrogen atoms are in mutually cis positions) were unambiguously determined in the early 1980s. The third isomer, gamma-[Ru(azpy)2Cl2], has for two decades, erroneously, been assumed to be the all-trans isomer. In a recent communication we have proven that for this gamma isomer the chloride ions are indeed in a trans geometry, but the pyridine nitrogen and azo nitrogen atoms of the two azpy ligands are in mutually cis geometries. In this paper the isolation of a fourth isomer is presented, the hitherto unknown delta-[Ru(azpy)2Cl2]. The isomeric structure of delta-[Ru(azpy)2Cl2] has been determined by 1H-NMR spectroscopy and single-crystal X-ray diffraction analysis, and is the all-trans isomer. The bis(azpy)-ruthenium(II) isomers are of interest because of the pronounced cytotoxicity they exhibit against tumour cell lines and could be very useful in the search for structure-activity relationships of antitumour-active ruthenium complexes, as among the isomers there is a significant difference in activity. It is of paramount importance to have a good understanding of the structural and spectroscopic properties of these complexes, which in this paper are compared and discussed, with a particular emphasis on 1D and 2D 1H NMR spectroscopies. Copyright 2004 The Royal Society of Chemistry
Dinuclear ruthenium(II) complexes[{(L)ClRuII}2}(μ-tppz)2+)(L = an arylazopyridine ligand) incorporating tetrakis(2-pyridyl)-pyrazine (tppz) bridging ligand: Synthesis, structure and spectroelectrochemical properties
Chanda, Nripen,Laye, Rebecca H.,Chakraborty, Soma,Paul, Rowena L.,Jeffery, John C.,Ward, Michael D.,Lahiri, Goutam Kumar
, p. 3496 - 3504 (2008/10/08)
A series of dinuclear complexes [{(L1-4)ClRuII}2(μ-tppz)][ClO 4]2 {[1](ClO4)2 to [4](ClO4)2} has been prepared, in which two {RuII(L1-4)Cl}+ fragments [L= a 2-arylazopyridine ligand of the type 2-(C5H4N)-N=N-C6H4R; for L1, R = H; L2, R = p-Me; L3, R = p-Cl; L4, R = m-Me] are linked by the bridging ligand tppz [2,3,5,6-tetrakis(2-pyridyl)pyrazine]. A single isomer forms during the synthesis in each case, and the crystal structure of [4](ClO4)2 shows it to be a twofold-symmetric isomer with each ligand L arranged such that its pyridine donor is on the long axis of the molecule (trans to the pyrazine ring of tppz) and the azo donor is trans to one of the pyridyl donors of tppz. This allows the peripheral aryl ring attached to the azo unit of each ligand L to be oriented over either face of the bridging ligand giving a three-layer π-stacked (aryl-pyrazine-aryl) sandwich. Electrochemical studies revealed (i) separations of 190-250 mV (depending on the aryl substituent of L) between the successive Ru(II)/Ru(III) couples, indicative of a significant inter-metallic electronic coupling, and (ii) several ligand-based reductions of the π-acceptor pyrazine and arylazopyridine ligands. A UV/Vis/NIR spectroelectrochemical study showed the presence of an IVCT transition at ca. 1900 nm in MeCN for the Ru(II)-Ru(III) mixed-valence states, whose narrowness is indicative of borderline class III behaviour. Several reduced forms of the complexes were also spectroscopically characterised.
Ruthenium terpyridine complexes incorporating azo-imine based ancillary ligands. Synthesis, crystal structure, spectroelectrochemical properties and solution reactivities
Mondai, Biplab,Walawalkar, Mrinalini G.,Lahiri, Goutam Kumar
, p. 4209 - 4217 (2007/10/03)
Ruthenium terpyridine complexes of the type [RuII(trpy)(L)(X)][ClO4]n 1-15 [trpy = 2,2′ :6,2″-terpyridine; L = NC5H4N=NC6H4(R), R = H, m-Me, m-Cl, p-Me orp-Cl; X = Cl- n = 1 (1-5); H2O, n = 2 (6-10) or OH-, n = 1 (11-15)] have been synthesized. The single crystal structures of 1 and 6 were determined. Complex 4 develops in two possible isomeric forms whereas all other complexes stabilise preferentially in one isomeric form. The complexes exhibit strong MLCT bands near 500 nm and ligand based transitions in the UV region. 1-5 exhibit moderately strong emissions at 77 K near 600 nm. The chloro (1-5) and the hydroxo (11-15) complexes display ruthenium(m)-ruthenium(ii) couples and three to four successive one-electron ligand based reductions. The aqua-complexes (6-10) exhibit a reversible 2e-/2H+ single-step oxidation process in the pH range 1-5.5 corresponding to the [RuII(trpy)(L)(H2O)]2+-[Ru Iv(trpy)(L)(O)]2+ couple and the potential decreases linearly with increase in pH. The chemical oxidations of 6-10 by an excess of CeIV in 0.5 M H2SO4 also lead to the formation of corresponding [RuIV(trpy)(L)(O)]2+. The oxo-complexes are stable only in the presence of an excess of CeIV, otherwise they catalyse the oxidation of water to dioxygen and convert back into the parent aqua-species. The pseudo first order rate constant of the process [RuIV(trpy)(L)(O)]2+ → [RuII(trpy)(L)(H2O)]2+ has been determined. The Royal Society of Chemistry 2000.
Use of Silver(I) Complexes in Synthesis of Bis- and Tris- Complexes of Ruthenium(II) and Investigation of Solid-state Isomerisation
Deb, Alok K.,Kakoti, Maushumi,Goswami, Sreebrata
, p. 3249 - 3252 (2007/10/02)
Efficient, new and direct synthetic routes to isomeric and 2*H2O complexes, based on the reaction of hydrated RuCl3 and ClO4, have been elaborated.The identity of the compounds were established from el
