Premium
Reactivity studies of 2,3,5,6‐Tetra(2‐pyridyl) pyrazine (tppz) with first‐row transition metal ions
Author(s) -
CamposFernández Cristian S.,
Smucker Bradley W.,
Clérac Rodolphe,
Dunbar Kim R.
Publication year - 2002
Publication title -
israel journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.908
H-Index - 54
eISSN - 1869-5868
pISSN - 0021-2148
DOI - 10.1560/ywhr-r8be-2plf-7fnn
Subject(s) - pyrazine , chemistry , crystallography , reactivity (psychology) , metal , ligand (biochemistry) , magnetic susceptibility , ferromagnetism , ion , stereochemistry , receptor , organic chemistry , medicine , biochemistry , physics , alternative medicine , pathology , quantum mechanics
Reactions of 2,3,5,6‐tetra(2‐pyridyl) pyrazine (tppz) with [ML 6 ][X] 2 (L = CH 3 CN, H 2 O;X = [BF 4 ] − , [ClO 4 ] − , [NO 3 ] − [BArF] − (BArF ‐ B[3,5‐C 6 H 3 (CF 3 ) 2 ] 4 ) lead to the high‐yield formation of mononuclear [M(tppz) 2 ] 2+ , (M = Mn II , Fe II , Co II , and Ni II ) and dinuclear [Ni 2 (tppz)(CH 3 CN) 6 ] 4+ species. The new compounds were fully characterized by X‐ray crystallographic, spectroscopic, and magnetic susceptibility measurements. Surprisingly, the 2:1 M:tppz reactions did not lead to isolation of the dinuclear species except in the case of Ni(II). It was further noted that even in the case of the Ni reactions, the nuclearity of the product depends on the choice of anions and the reaction conditions. Magnetic measurements of the mononuclear species [Co(tppz) 2 ] 2+ revealed thermally induced spin‐crossover behavior from a high‐spin S = 3/2 at higher temperatures to a low‐spin S = 1/2 complex at lower temperatures. The dinuclear compound [Ni 2 (tppz)(CH 3 CN) 6 ] 4+ exhibits a weak anti‐ferromagnetic interaction through the bridging tppz ligand.