Analytical Sciences

Abstract − Analytical Sciences, 29(8), 773 (2013).

Solvent-dependent Assembly of Discrete and Continuous CoCl2 Adamantane-based Ligand Complexes: Observations by CSI–Mass Spectrometry and X-ray Crystallography
Kazuaki OHARA, Masahide TOMINAGA, Isao AZUMAYA, and Kentaro YAMAGUCHI
Faculty of Pharmaceutical Sciences at Kagawa Campus, Tokushima Bunri University, Shido, Sanuki, Kagawa 769-2193, Japan
Discrete and continuous coordination structures were obtained in single crystals of CoCl2 and an adamantane-based bidentate ligand bearing imidazolyl groups, depending on the methanol concentration in a methanol–chloroform mixture. Single-crystal X-ray structure analysis revealed that the metal centers exhibited a tetrahedral geometry in the discrete complex and an octahedral geometry in the continuous metal complex. Conventional analytical methods, including UV-vis and NMR spectroscopy, could not identify those two complexes in solution. In contrast, cold-spray ionization mass spectrometry could detect differences between the discrete complex and the continuous metal complex, and ion peaks due to continuous ligand adducts were found only in the spectrum of the continuous metal complex.