Metal Complexation of Thiacrown Ether Macrocycles by Electrospray Ionization Mass Spectrometry

Abstract

In the present study, electrospray ionization mass spectrometry is used to evaluate the metal-binding selectivities of an array of novel caged macrocycles for mercury(II), lead(II), cadmium(II), and zinc(II) ions. In homogeneous methanol/chloroform solutions as well as extractions of metals from aqueous solution by macrocycles in chloroform, it is found that the type of heteroatom (S, O, N), cavity size, and presence of other substituents influence the metal selectivities. Several of the macrocycles in this study bind mercury ion very selectively and efficiently in the presence of many other metal ions and have an avidity toward mercury that was tunable by the size and combination of heteroatoms in the macrocycle ring and the number of cage groups attached. The extraction mechanism was further investigated by determining the variation in extraction selectivity as a function of the counterions of the mercury salts.

Biphasic Electrospray Ionization for the Study of Interfacial Complexes

“…Copper ions were also found at m/z = 423.0 Th ). This contamination can be attributed to copper impurity in PbCl2, as reported by Williams et al, 23 or to the syringe needle oxidation (where the high voltage is applied) that is known to produce some metallic ions. 34 At lower concentrations of lead chloride (20 mM), no complexation was observed, and at higher concentrations (e. + is obtained at m/z = 394.9 Th.…”

“…33 For this reason, they are commonly used to extract heavy metals, for instance. 5,15,23 The complexation process depends on several parameters, but one of the most important is the size of the ring. HTCO is a thioether crown and has been widely employed.…”

“…21 In this way, organic droplets are formed in water; copper ion complexation was probed by MS. In general, these kinds of complexes are usually analyzed after extraction in chloroform 23 or by dissolving the compounds in different methanol/water or methanol/chloroform solutions. 24,25 Recently, our laboratory has developed different kind of microsprayers for ESI-MS based on various materials, geometries and configurations, [26][27][28] with the aim to probe different chemical reactions, such as tagging reactions.…”

An optical sensor for mercury ion based on the fluorescence quenching of tetra(p-dimethylaminophenyl)porphyrin

“…Moreover, these works all involved a very complex synthesis of fluorescent materials. As far as we know, some other analytical methods have been developed for the determination of mercury, such as electrochemical method [20][21][22][23][24][25][26], atomic absorption spectrometry [27][28][29][30] or cold-vapour inductively coupled plasma atomic emission [31], chromatographic determination [32][33][34], inductively coupled plasma-mass spectrometric analysis [35,36] or electrospray ionization mass spectrometry [37], room temperature phosphorimetry [38]. Although these methods are accurate, most require a tedious sample pre-treatment, sophisticated performance and/or expensive equipment.…”

1,1'‐Bis(oxazolin‐2‐yl)ferrocenes: An Investigation of Their Complexation Behavior toward [Pd(η3‐allyl)Cl]2

“…[54] ESI-MS has a number of advantages over other techniques; in particular, it provides information on the characteristic isotopic patterns of compounds (especially metal compounds) and allows low sample consumption and use of many compatible solvents. [49] In order to clarify the influence of the nature of the substituents on the catalytic potential of 1,1Ј-bis(oxazolin-2-yl)ferrocenes, several derivatives of the parent compound 1,1Ј-bis[(S)-4-tert-butyloxazolin-2-yl]ferrocene (12b) were synthesized and tested with respect to their catalytic potential in asymmetric allylic substitution, where the catalytic activity depends strongly on the formation of chelate structures between multidentate ligands and transition metals. [55,56] The coordination behavior of new 1,1Ј-bis(oxazolin-2-yl)ferrocenes bearing alkyl (1b, 7b, and 12b) or aryl substituents (14b) in the 4-position of the oxazoline ring toward [Pd(η 3 -C 3 H 5 )Cl] 2 was studied in detail by ESI-MS.…”