Electron ionization and fast atom bombardment mass spectral study for differentiation of ligand of zinc(II) (–)‐sparteine and (–)‐α‐isosparteine complexes

Abstract

Electron ionization and fast atom bombardment mass spectral study for differentiation of ligand of zinc(II) (-)-sparteine and (-)-a-isosparteine complexesThe (-)-sparteine bis-quinolizidine alkaloid produced by lupine species has generated much interest due to its pharmacological properties, 1-3 and its application in asymmetric synthesis. 4,5 The basic bis-quinolizidine system of (-)-sparteine consists of four rings, two of which (A/B) form a double-chair system of trans-quinolizidine, which is relatively resistant (for thermodynamic reasons) to conformationalconfigurational changes. The second system of rings (C/D) is much more susceptible to inversion at the N16 nitrogen atom and it can occur in either the trans boat-chair or the cis double-chair conformation. According to Haasnoot, 6 sparteine adopts exclu-

Mass Spectrometry of Metal Complexes of Bis-Quinolizidine Alkaloids: Electron Ionization and Fast Atom Bombardment Mass Spectral Study of Copper(II) (–)-Sparteine and (–)-α-Isosparteine Complexes

“…As a continuation of our previous studies of the EI [36][37][38] and fAB 39 mass fragmentations of the derivatives of (-)-sparteine, as well as EI and fAB mass fragmentation of zinc(II) (-)-sparteine and (-)-a-isosparteine complexes, 40 we have extended our investigation to the copper(II) complexes of (-)-sparteine and (-)-a-isosparteine. considerable effort has been devoted to the study of these compounds by infrared and nuclear magnetic resonance spectroscopy, as well as by X-ray methods.…”

“…the same phenomenon was observed in the EI mass spectra of analogous complexes of Zn(II) with (-)-sparteine and (-)-a-isosparteine. 40 In the EI mass spectra Table 1. Relative abundances of ions in the EI mass spectra of 1-10.…”

JMS Letters

“…S2, Supporting Information). It should be pointed out that in the ESI mass spectra of 5 and 6, the even-electron ions C 16 (Table 3, Scheme 3). In the ESI fragmentation of protonated molecules, C 16 H 28 N 2 MeX 2 + Hl + of complexes 1-6 ejections of neutral molecules of HX gave the even-electron fragment ions a, as well as the eliminations of MeX 2 species lead to the evenelectron fragment ion C 16 H 28 N 2 + Hl + b.…”

“…[10][11][12][13][14][15] Some effort has been devoted to the electron ionization and fast atom bombardment mass spectral study for differentiation of ligand, as well as metals in the series of Zn +2 and Cu +2 dichloride (dibromide, diacetate, diformate, dithioacetate) complexes of (-)-sparteine and (-)-aisosparteine. [16,17] Several principles are fragmentally used to predict stabilities and binding preferences: the Irving-Williams series [18] and the hard-soft acid-base concept. The Irving-Williams series state the complex stabilities should typically follow their order Co +2 < Ni +2 < Cu +2 > Zn +2 .…”

“…and (-)-a-isosparteine has been previously used in our laboratory. [16,17] Low-resolution and high-resolution mass spectra were recorded using a model 432 two-sector mass spectrometer [AMD-Intectra GmbH D-27243 Harpstedt, Germany] ionizing voltage 70 eV, accelerating voltage 8 kV, mass resolution 10 000 at 10% valley. Samples were introduced by a direct insertion probe at a source temperature of~150 C. The elemental compositions of the ions were determined by peak matching method relative to perfluorokerosene.…”