TY - JOUR

T1 - Spin crossover in iron(II) hexafluorophosphate complexes with 2-(pyridin-2-yl)-4-(3,5-di-R-1H-pyrazol-1-yl)-6-methylpyrimidines

AU - Bushuev, Mark B.

AU - Vinogradova, Katerina A.

AU - Gatilov, Yuri V.

AU - Korolkov, Ilya V.

AU - Nikolaenkova, Elena B.

AU - Krivopalov, Viktor P.

PY - 2017/10/1

Y1 - 2017/10/1

N2 - Iron(II) hexafluorophosphate complexes with N,N,N-tridentate ligands, 2-(pyridin-2-yl)-4-(1H-pyrazol-1-yl)-6-methylpyrimidine (L(H,H)) and 2-(pyridin-2-yl)-4-(3,5-dimethyl-1H-pyrazol-1-yl)-6-methylpyrimidine (L(Me,Me)) were synthesized by reacting FeCl2·4H2O, (NBu4)PF6 and L(H,H) or L(Me,Me) in alcohol media. Supramolecular 3D structure of [FeL(H,H)2](PF6)2·nH2O is organized by CH…π interactions, π…π-stacking and CH…F hydrogen bonds. In the stricture of [FeL(Me,Me)2](PF6)2·nH2O the cations and anions are assembled into a 3D network via CH…F hydrogen bonds and lone pair…π interactions. Both complexes demonstrate high thermal stability. Under vacuum, the complex [FeL(Me,Me)2](PF6)2·nH2O is predominantly in the low spin state below 400 K, but at higher temperatures it shows gradual spin state switching which remains incomplete even at 495 K. Under vacuum or in sealed ampoule in the first heating run the complex [FeL(H,H)2](PF6)2·nH2O shows abrupt spin state switching related to dehydration near 400 K. On further thermal cycling under vacuum the complex demonstrates gradual spin crossover curve centered at ca. 250 K, whereas in sealed ampoules this compound demonstrates a very abrupt transition near 250 K.

AB - Iron(II) hexafluorophosphate complexes with N,N,N-tridentate ligands, 2-(pyridin-2-yl)-4-(1H-pyrazol-1-yl)-6-methylpyrimidine (L(H,H)) and 2-(pyridin-2-yl)-4-(3,5-dimethyl-1H-pyrazol-1-yl)-6-methylpyrimidine (L(Me,Me)) were synthesized by reacting FeCl2·4H2O, (NBu4)PF6 and L(H,H) or L(Me,Me) in alcohol media. Supramolecular 3D structure of [FeL(H,H)2](PF6)2·nH2O is organized by CH…π interactions, π…π-stacking and CH…F hydrogen bonds. In the stricture of [FeL(Me,Me)2](PF6)2·nH2O the cations and anions are assembled into a 3D network via CH…F hydrogen bonds and lone pair…π interactions. Both complexes demonstrate high thermal stability. Under vacuum, the complex [FeL(Me,Me)2](PF6)2·nH2O is predominantly in the low spin state below 400 K, but at higher temperatures it shows gradual spin state switching which remains incomplete even at 495 K. Under vacuum or in sealed ampoule in the first heating run the complex [FeL(H,H)2](PF6)2·nH2O shows abrupt spin state switching related to dehydration near 400 K. On further thermal cycling under vacuum the complex demonstrates gradual spin crossover curve centered at ca. 250 K, whereas in sealed ampoules this compound demonstrates a very abrupt transition near 250 K.

KW - Iron(II)

KW - Non-covalent interactions (Lone pair–π, CH…π, π…π and CH…F)

KW - Pyrazole

KW - Pyridine

KW - Pyrimidine

KW - Spin crossover

KW - SYSTEM

KW - LIGAND SUBSTITUTION

KW - STABILIZATION

KW - STATE

KW - POLYMORPHISM

KW - Non-covalent interactions (Lone pair-pi, CH center dot center dot center dot pi, pi center dot center dot center dot pi and CH center dot center dot center dot F)

KW - SALTS

KW - TRANSITION

KW - TEMPERATURE

KW - 2,6-DI(PYRAZOL-1-YL)PYRIDINE

KW - JAHN-TELLER DISTORTION

UR - http://www.scopus.com/inward/record.url?scp=85027396436&partnerID=8YFLogxK

U2 - 10.1016/j.ica.2017.08.006

DO - 10.1016/j.ica.2017.08.006

M3 - Article

AN - SCOPUS:85027396436

VL - 467

SP - 238

EP - 243

JO - Inorganica Chimica Acta

JF - Inorganica Chimica Acta

SN - 0020-1693

ER -