| Autor: |
Sheng HJ; State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China., Xia CC; State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China., Zhang XY; State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China., Zhang CC; State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China., Ji WJ; State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China., Zhao Y; State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China., Wang XY; State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China. |
| Abstrakt: |
Four iron(III) complexes, [Fe(qsal-4-F) 2 ]Y·sol (Hqsal-4-F = 4-fluoro- N -(8-quinolyl)salicylaldimine; Y = NO 3 - , sol = 0.91MeOH·0.57H 2 O ( 1 NO3 ); Y = PF 6 - ( 2 PF6 ); Y = BF 4 - ( 3 BF4 ); Y = OTf - , sol =1.5MeOH ( 4 OTf )), with a new 4-position substituted qsal type ligand Hqsal-4-F have been synthesized and structurally and magnetically characterized. Complexes 1 NO3 - 3 BF4 consist of 1D chains formed by the [Fe(qsal-4-F) 2 ] + cations connected by π-π and C-H···O interactions, which are further linked by more weak interactions to form 2D layers and 3D networks. On the other hand, complex 4 OTf has a structure of nearly isolated 1D column where the [Fe(qsal-4-F) 2 ] + cations are connected by π-π, C-H···π, and C-F···π interactions. Magnetic studies revealed the occurrence of two-step symmetry-breaking SCO in 1 NO3 and two-step gradual SCO in 2 PF6 . Complex 3 BF4 undergoes a gradual SCO, whereas 4 OTf remains almost high-spin. The smaller anions tend to stabilize the low-spin state, while larger anions tend to stabilize the high-spin state. In addition, the intermediate spin state of 1 NO3 could be thermally trapped by quenching from the high temperature, thereby kinetically suppressing the spin transition to the full low-spin state. This work represents a good example that the position of the substituent and the anions plays critical roles in the preparation of SCO materials with tunable properties. |
