| Autor: |
Zaiter S; School of Chemistry, The University of Sydney, New South Wales 2006, Australia., Kirk C; Chemical Crystallography, Chemistry Research Laboratory, Mansfield Road, Oxford, UK., Taylor M; School of Chemistry, UNSW Sydney, New South Wales 2052, Australia. s.neville@unsw.edu.au., Klein YM; Department of Chemistry, University of Basel, BPR 1096, Mattenstrasse 24a, CH-4058, Switzerland., Housecroft CE; Department of Chemistry, University of Basel, BPR 1096, Mattenstrasse 24a, CH-4058, Switzerland., Sciortino NF; School of Chemistry, The University of Sydney, New South Wales 2006, Australia., Clements JE; School of Chemistry, The University of Sydney, New South Wales 2006, Australia., Cooper RI; Chemical Crystallography, Chemistry Research Laboratory, Mansfield Road, Oxford, UK., Kepert CJ; School of Chemistry, The University of Sydney, New South Wales 2006, Australia., Neville SM; School of Chemistry, UNSW Sydney, New South Wales 2052, Australia. s.neville@unsw.edu.au. |
| Abstrakt: |
We probe the effect of heteroatom substitution on the spin crossover (SCO) properties of dinuclear materials of the type [Fe 2 (NCX) 4 (R-trz) 5 ]·S (X = S, Se; S = solvent; R-trz = (E)-N-(furan-2-ylmethylene)-4H-1,2,4-triazol-4-amine (furtrz); (E)-N-(thiophen-2-ylmethylene)-4H-1,2,4-triazole-4-amine (thtrz)). For the furtrz family ([Fe 2 (NCX) 4 (furtrz) 5 ]·furtrz·MeOH; X = S (furtrz-S) and X = Se (furtrz-Se)) gradual and incomplete one-step SCO transitions are observed (furtrz-S (T 1/2 = 172 K) and furtrz-Se (T 1/2 = 205 K)) and a structural evolution from [HS-HS] to [HS-LS] per dinuclear species. Contrasting this, within the thtrz family ([Fe 2 (NCX) 4 (thtrz) 5 ]·4MeOH; X = S (thtrz-S) and X = Se (thtrz-Se)) more varied SCO transitions are observed, with thtrz-S being SCO-inactive (high spin) and thtrz-Se showing a rare complete two-step SCO transition (T 1/2(1,2) = 170, 200 K) in which the Fe II sites transition from [HS-HS] to [HS-LS] to [LS-LS] per dinuclear unit with no long range ordering of spin-states at the intermediate plateau. Detailed structure-function analyses have been conducted within this growing dinuclear family to rationalise these diverse spin-switching properties. |
