The molecular and supramolecular aspects in mononuclear manganese(iii) Schiff-base spin crossover complexesElectronic supplementary information (ESI) available: Additional structural and computational details. CIF files for 1-4. CCDC 1544516, 1544518, 1544519, 1544521, 1544523 and 1544525-1544529. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c7dt01718a

• Main Authors: Wang, Shi, Li, Ya-Juan, Ju, Fei-Fei, Xu, Wu-Tan, Kagesawa, Koichi, Li, Yong-Hua, Yamashita, Masahiro, Huang, Wei
• Format: Journal Article
• Language: English
• Published: 22.08.2017
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/c7dt01718a

Manganese( iii ) hexadentate Schiff base complexes ([Mn(sal-N-1,5,8,12)]Y·S, Y = AsF 6 ( 1 ); Y = SbF 6 ( 2 ); Y = NO 3 , S = C 2 H 5 OH ( 3 ) and Y = Cl ( 4 )) have been investigated to determine the impact of anion effects, intramolecular ligand distortions, and intermolecular supramolecular structures on the spin crossover (SCO) behavior. The crystal structure of [Mn(sal-N-1,5,8,12)]PF 6 , a complex known to exhibit an abrupt SCO behavior with an 8 K hysteresis window, reveals that this complex has a temperature-dependent anion order-disorder transition that disrupts the hydrogen-bonding chain upon SCO, indicating that hydrogen bonds between cations and anions greatly influence the magnetic properties. The SCO in 1 is mediated by intermolecular hydrogen-bonding interactions. The subtle balance of these hydrogen bonds induces a cooperative SCO process with a hysteresis width of 18 K, which is the largest one reported in the d 4 SCO chemistry. For 2 , crystal structural analysis indicates that changing the anion from AsF 6 − to SbF 6 − led to close stackings between phenyl groups from ligands. These stackings preclude the spin transition of the [Mn(sal-N-1,5,8,12)] + cations. With NO 3 − and Cl − as counterions, the [Mn(sal-N-1,5,8,12)] + cations are arranged more loosely and exhibit gradual SCO in the temperature range of 300-100 K. Careful evaluation of the supramolecular structures of these complexes and similar complexes reported previously revealed strong correlation between the supramolecular packing forces and their magnetic properties. A cooperative SCO process with a hysteresis width of 18 K is the largest one reported in d 4 SCO chemistry.