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Inter‐ and Intrachain Spin‐Transition Processes in One‐Dimensional Polynuclear Iron(III) Complexes of N , N′ ‐Ethylenebis(acetylacetonylideneimine) Bridged by 1,3‐Bis(4‐pyridyl)propane and 1,4‐Bis(imidazolyl)butane
Author(s) -
Imatomi Shinya,
Hashimoto Shingo,
Matsumoto Naohide
Publication year - 2009
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/ejic.200800778
Subject(s) - chemistry , butane , crystallography , propane , spin crossover , chain (unit) , atmospheric temperature range , bond length , crystal structure , spin (aerodynamics) , single crystal , stereochemistry , thermodynamics , catalysis , organic chemistry , physics , astronomy
Two one‐dimensional (1D) polynuclear iron(III) complexes, [Fe III (acacen)(bpyp)]BPh 4 ( 1 ) and [Fe III (acacen)(bimb)]BPh 4 ( 2 ), were synthesized [acacen = N , N′ ‐ethylenebis(acetylacetonylideneiminato); bpyp = 1,3‐bis(4‐pyridyl)propane; bimb = 1,4‐bis(imidazolyl)butane]. Complexes 1 and 2 show gradual spin‐crossover (SCO) behavior over a wide temperature range from 100 to 300 K and from 220 to higher than 350 K, respectively. The single‐crystal X‐ray structures of two complexes in the high‐spin (HS), low‐spin (LS), and the midpoint between HS and LS states were determined. Crystal structures of both complexes consist of two molecular units (Fe1 and Fe2), where complex 1 consists of two crystallographically independent 1D chains and complex 2 consists of one 1D chain involving two molecular units. At the temperature midway between the HS and LS states, the Fe–N bond lengths in the two units are different from each other. At the midpoint, complex 1 consists of alternately arrayed independent HS and LS chains, whereas complex 2 consists of alternately arrayed HS and LS units within a chain. The results demonstrate two different SCO mechanisms of a 1D complex, that is, SCO occurs in chain‐by‐chain fashion for 1 and in adjacent Fe units within a chain for 2 . (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)