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Synthesis, Structure, and Magnetic Properties of a Tris[3‐(2‐pyridyl)‐1,2,4‐triazole]iron(II) Spin‐Crossover Complex
Author(s) -
Stassen Arno F.,
de Vos Matthijs,
van Koningsbruggen Petra J.,
Renz Franz,
Ensling Jürgen,
Kooijman Huub,
Spek Anthony L.,
Haasnoot Jaap G.,
Gütlich Philipp,
Reedijk Jan
Publication year - 2000
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/1099-0682(200010)2000:10<2231::aid-ejic2231>3.0.co;2-b
Subject(s) - chemistry , orthorhombic crystal system , tetrafluoroborate , crystallography , spin crossover , mössbauer spectroscopy , 1,2,4 triazole , crystal structure , medicinal chemistry , ionic liquid , catalysis , organic chemistry
The synthesis and characterization of tris[3‐(pyridin‐2‐yl)‐1,2,4‐triazole]iron(II) bis(tetrafluoroborate), obtained from the reaction of 3‐(pyridin‐2‐yl)‐1,2,4‐triazole (Hpt) and hexaaquairon(II) tetrafluoroborate, [Fe(H 2 O) 6 ](BF 4 ) 2 , is described, together with its crystal structures at two temperatures. X‐ray crystallographic parameters are as follows: [Fe(Hpt) 3 ](BF 4 ) 2 · n H 2 O ( n ≈ 2) at 250 K: orthorhombic space group Pbam , a = 15.8068(18) Å, b = 17.2800(14) Å, c = 21.215(2) Å, V = 5794.7(10) Å 3 , and Z = 8. [Fe(Hpt) 3 ](BF 4 ) 2 · n H 2 O ( n ≈ 2) at 95 K: orthorhombic space group Pbam , a = 15.7080(12) Å, b = 17.1023(16) Å, c = 21.006(2) Å, V = 5643.1(9) Å 3 , and Z = 8. The Fe II ions are (at both temperatures) octahedrally surrounded in a mer ‐configuration. The complex has been subjected to both 57 Fe Mössbauer spectroscopy and magnetic susceptibility measurements. The 57 Fe Mössbauer spectrum shows the presence of two different iron(II) sites. The high‐spin fraction vs. T curve of the crossover, obtained by SQUID measurements, is gradual and without hysteresis, with T 1/2 = 135 K.