159221-73-5Relevant academic research and scientific papers
Spring-loaded Iron(II) complexes as magnetogenic probes reporting on a chemical analyte in water
Gondrand, Corentin,Touti, Fay?al,Godart, Estelle,Berezhanskyy, Yevgen,Jeanneau, Erwann,Maurin, Philippe,Hasserodt, Jens
, p. 1376 - 1382 (2015)
A paramagnetic quality may be established in an aqueous sample if it contains a molecular probe that responds to the addition of a chemical analyte by turning from a diamagnetic state into a paramagnetic one (off-on). We explore here a stable, low-spin, binary iron(II) complex that stores so much potential energy that its transformation by the target analyte leads to its fragmentation into a high-spin complex despite the imposing strength of the chelate effect. The underlying ligand is a mixed aminal, the components of which can be freely varied to optimize response kinetics with the initial probe stability preserved. With decreasing leaving-group character of the azole component, the probe stability improves, and the response kinetics diminish. An optimal arrangement can be found with a pyrazole paired with an electron-deficient aromatic carbaldehyde component (nitro substitution). The drastic electronic reversion associated with the reduction of the nitro group to an amino group is the principal reason for the observation of an initially stable probe that suffers swift fragmentation when reacted with a reductive analyte. A new low-spin iron(II) triazacyclononane-based complex, selected from four different candidates, acts as a molecular probe that turns a diamagnetic aqueous sample into a paramagnetic one as a response to a chemical analyte. The four complexes are prepared by a highly convergent synthetic protocol and give precious insights into structure-activity relationship (SAR) tendencies.
Synthesis, characterization and coordination chemistry of aminophenylbenzothiazole substituted 1,4,7-triazacyclononane macrocycles
Barreto, José,Venkatachalam, Taracad K.,Joshi, Tanmaya,Kreher, Ute,Forsyth, Craig M.,Reutens, David,Spiccia, Leone
, p. 128 - 138 (2013/06/05)
The synthesis and spectroscopic characterization of four new 2-(4-aminophenyl)benzothiazole substituted 1,4,7-triazacyclononane derivatives with and without appended pyridyl groups on the macrocycle is reported: 1-(2-(4-aminophenyl)benzothiazolyl)-2-oxoethyl)-1,4,7-triazacyclononane (L1), 1-(2-(4-aminophenyl)benzothiazolyl)-2-oxoethyl)-4-(2-pyridylmethyl)-1,4, 7-triazacyclononane (L2), 1-(2-(4-N-methylaminophenyl)benzothiazolyl)-2- oxoethyl)-4-(2-pyridylmethyl)-1,4,7-triazacyclononane (L3), 1,4-bis(2- pyridylmethyl)-7-(2-(4-aminophenyl)benzothiazolyl)-2-oxoethyl)-1,4, 7-triazacyclononane (L4). The ligands have been applied in the synthesis of a series of copper (II) complexes, [Cu(L1)(OH2)](ClO4) 2·0.5ACN (C1), [Cu(L3)](ClO4)2· ACN (C2) and [Cu(L4)(OH2)](ClO4)2·0.5THF (C4) whose structures have been determined by X-ray crystallography. As commonly observed for Cu(II) complexes of 1,4,7-triazacyclononane derivatives, the geometry of the metal centre ranges from distorted square pyramidal to pseudo-octahedral. Notably, the amide carbonyl coordinates to the copper(II) centre in C1 and C2 but not in C4 where the presence of an additional pyridyl group results in an N5 coordination sphere.
