Electrospray mass spectrometric studies of the complexational behavior of maleonitrile thiacrown ethers with various metals

Abstract

Electrospray ionization was employed to study the mass spectrometric behavior of the maleonitrile tetrathiacrown ethers mn12S 4 (1) and mn13S 4 (2) and maleonitrile pentathiacrown ether mn15S 5 (3) and of their complexes with various metal salts (MX 2 , M --Pd, Pt, Ni, Co, Fe; X --Cl, CrCl 3 , Ni (BF 4 ESI has also been used to determine the binding constants for various complexes in solution. Absolute and relative binding energies of metal-containing complexes can be estimated on the basis of energy-variable collision-induced dissociation (CID) measurements. In this context, Brodbelt and co-workers studied the dissociation pattern of differently charged polyether, crown ether and polypyridyl transition metal complexes. 26,27 In general, these studies reveal that rearrangement reactions involving the loss of small neutrals from the large ligands or the loss of intact ligands from multi-ligand metal complexes are characteristic. [26][27][28][29][30] In the present paper we report on ESI-MS studies of complexes of the crown ethers mn12S 4 (1), mn13S 4 (2) and mn15S 5 (3) 24c (cf. Fig. 1) with first-row transition metals Cr(III), Fe(II), Co(II), Ni(II) and Cu(II) and second/third-row metals Pd(II), Pt(II), Cd(II) and the main group metal thallium. The CID spectra of these complexes were also examined to evaluate the stability of the different complex types. Finally, the fragmentation patterns of the present complexes were compared in order to correlate them with the diameter of the cations and their binding properties. EXPERIMENTAL SynthesesThe syntheses of crown ethers mn12S 4 (1), 24b mn13S 4 (2),

Complexation of diazaperylene and bisisoquinoline with transition metal ions in the gas phase studied by electrospray ionization mass spectrometry

“…The binding energies of the transition metal complexes can be estimated on the basis of energy‐variable collision‐induced dissociation (CID) measurements 22–24. We have already employed the two methods successfully for studying both qualitatively and quantitatively the complexation of maleonitrile thiacrown ethers with various metal ions 25…”

Metabolite characterization of a novel anti‐cancer agent, icotinib, in humans through liquid chromatography/quadrupole time‐of‐flight tandem mass spectrometry

“…Neutral losses of 44, 88 and 114 Da suggest the existence of a 12‐crown‐4 ether moiety (ring D). The MS/MS profile consists of the fragmentation characteristics of crown ether compounds formed after a sequential loss of C 2 H 4 X (X = O, S) units . Fragment ions at m/z 278.0916 and 304.1080 suggested the presence of 4‐(3‐ethynylphenylamino)quinazoline (rings A, B and C) (Tables and ).…”

“…The MS/MS profile consists of the fragmentation characteristics of crown ether compounds formed after a sequential loss of C 2 H 4 X (X = O, S) units. [4,12] Fragment ions at m/z 278.0916 and 304.1080 suggested the presence of 4-(3-ethynylphenylamino)quinazoline (rings A, B and C) ( Tables 1 and 2). 1 H-NMR signals and NMR correlations are summarized in Table 3 and Fig.…”

Determination of the relative ligand‐binding strengths in heteroleptic IrIIIcomplexes by ESI‐Q‐TOF tandem mass spectrometry

“…The stability of transition metal complexes is not only influenced by the nature of the coordinated ligands (i.e. polarizability and steric demand) but also via the size and the surface charge density of the transition metal ion . Accordingly, the fragmentation of Ir III complexes 2 under ESI mass spectrometric conditions was compared with that of complexes containing Rh III ions as the lighter group 9 metal ion (because of synthetic reasons, the analogous bis ‐cyclometalated Co III S‐tpy complexes could not be investigated).…”