The recently discovered cytoprotective action of CO has raised interest in exogenous CO-releasing materials (CORMs) such as metal carbonyls (CO complexes of transition metals). To achieve control on CO delivery with metal carbonyls, we synthesized and characterized three Mn(I) carbonyls, namely, [Mn(tpa)(CO)(3)]ClO4 [1, where tpa = tris(2-pyridyl)amine], [Mn(dpa)(CO)(3)]Br [2, where dpa = N,N-bis(2-pyridylmethyl)amine], and [Mn (pqa) (CO)(3)] ClO4 [3, where pqa = (2-pyridylmethyl)(2-quinolylmethyl)amine], by crystallography and various spectroscopic techniques. All three carbonyls are sensitive to light and release CO when illuminated with low-power UV (5-10 mW) and visible (lambda > 350 nm, similar to 100 mW) light. The sensitivity of 1-3 to light has been assessed with respect to the number of pyridine groups in their ligand frames. When a pyridine ring is replaced with quinoline, extended conjugation in the ligand frame increases the absorptivity and makes the resulting carbonyl 3 more sensitive to visible light. These photosensitive CORMs (photoCORMs) have been employed to deliver CO to myoglobin under the control of light. The superior stability of 3 in aqueous media makes it a photoCORM suitable for inducing vasorelaxation in mouse aortic muscle rings.
Modification and Optimization of the Bis-picolylamide-Based Relay Protection for Carboxylic Acids to be Cleaved by Unusual Complexation with Cu2+ Salts
摘要:
A simple modification of our recently published protection scheme for carboxylic acids as amides resulted in a new protecting group with significantly improved properties. It requires shorter reaction times for deprotection and allows us to replace Cu(OTf)(2) by CuCl2, indicating at the same time the importance of the nature of the anion of the Cu2+ source. Since the new scheme fulfills all criteria required for an ideal protection group it should find widespread application in synthetic organic chemistry.
A NBD-based selective colorimetric and fluorescent chemosensor for Hg2+
作者:Jin Hoon Kim、Jin Young Noh、In Hong Hwang、Jae Jun Lee、Cheal Kim
DOI:10.1016/j.tetlet.2013.05.074
日期:2013.7
A new NBD-based sensor bearing a dipicolylamine derivative, (2-pyridylmethyl)(2-quinolylmethyl)amine (1), was synthesized, and its chromogenic and fluorogenic behaviors toward various metal ions were investigated in methanol solution. Chemosensor 1 selectively detected Hg2+ ions through color change from yellow to colorless. In addition, chemosensor 1 exhibited highly Hg2+-selective ON-OFF fluorescence quenching behavior and was shown to discriminate various competing metal ions, particularly, such as Cu2+, Ag+, and Pb2+. The binding mode of 1-Hg2+ was found to be a 1:2 complex formation, based on Job plot and H-1 NMR titration. (C) 2013 Elsevier Ltd. All rights reserved.
An anthracene-based fluorescent chemosensor for Zn2+
作者:Jin Hoon Kim、Jin Young Noh、In Hong Hwang、Juhye Kang、Jinheung Kim、Cheal Kim
DOI:10.1016/j.tetlet.2013.02.102
日期:2013.5
A new zinc ion sensor 1-(anthracen-9-yl)-N-(pyridin-2-ylmethyl)-N-(quinolin-2-ylmethyl)methanamine 1 was synthesized by incorporating a dipicolylamine derivative as a binding unit and an anthracene group as a fluorescence signaling unit. The anthracene-based receptor 1 was highly selective for Zn2+ with a fluorescence enhancement and a remarkable red shift in aqueous solution, whereas this chemosensor showed no response to other metals, especially Cd2+ ion. The composition of the complex 1-Zn2+ turned out 1:1, based on Job's plot, ESI-mass analysis, and H-1 NMR titration. (C) 2013 Elsevier Ltd. All rights reserved.