Solvent Dependence of the Magnetic Ordering Temperature for Decamethylferrocenium Tetracyanoethenide, [FeIII(C5Me5)2][TCNE]·Solvent
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- 作者：Michelle L. Taliaferro ; Trent D. Selby ; and Joel S. Miller
- 刊名：Chemistry of Materials
- 出版年：2003
- 出版时间：September 23, 2003
- 年：2003
- 卷：15
- 期：19
- 页码：3602 - 3606
- 全文大小：342K
- 年卷期：v.15,no.19(September 23, 2003)
- ISSN：1520-5002
文摘
The magnetic properties of monoclinic [FeIII(C5Me5)2]
+[TCNE]-·MeCN (1·MeCN) havebeen measured and compared to that of orthorhombic [FeIII(C5Me5)2]+[TCNE]- (1). Peaksin both 
'(T) and ' '(T) are observed verifying that antiferromagnetic ordering is not presentin either 1 or solvated 1 (1·S). 1·MeCN facilely loses MeCN and both desolvated 1·MeCNand 1 have the same magnetic behavior (Tf = 4.96 ± 
0.03 K). In contrast, solvated 1·MeCN has a reduced Tf of 2.87 ± 0.02 K. This is ascribed to the layers of MeCN that separatethe pairs of layers of parallel chains of [Fe(C5Me5)2][TCNE], which reduce the 3-D magneticcoupling leading to a lower ordering temperature. Formation of other magnetically orderedsolvates, 1·S (S = EtCN, PrCN, PhCN, 1,2-C6H4Cl2, NCC4H8CN), with 2.87 < Tf < 4.82 K,which, except for S = PrCN, also have Tf = 4.96 ± 0.03 K upon desolvation. Addition ofTHF to 1 leads to an enhanced Tf of 5.50 ± 0.11 K, which is attributed to an external pressure(ca 2.5 kbar) induced by the THF solvent that does not occur for the nitrile-based solvents.The desolvated materials exhibit a small frequency dependence in the ac susceptibility,'(T,f). This is typically an order of magnitude lower than the frequency dependence for thesolvated species, which is indicative of enhanced glassiness and disorder.
+[TCNE]-·MeCN (1·MeCN) havebeen measured and compared to that of orthorhombic [FeIII(C5Me5)2]+[TCNE]- (1). Peaksin both '(T) and ' '(T) are observed verifying that antiferromagnetic ordering is not presentin either 1 or solvated 1 (1·S). 1·MeCN facilely loses MeCN and both desolvated 1·MeCNand 1 have the same magnetic behavior (Tf = 4.96 ± 0.03 K). In contrast, solvated 1·MeCN has a reduced Tf of 2.87 ± 0.02 K. This is ascribed to the layers of MeCN that separatethe pairs of layers of parallel chains of [Fe(C5Me5)2][TCNE], which reduce the 3-D magneticcoupling leading to a lower ordering temperature. Formation of other magnetically orderedsolvates, 1·S (S = EtCN, PrCN, PhCN, 1,2-C6H4Cl2, NCC4H8CN), with 2.87 < Tf < 4.82 K,which, except for S = PrCN, also have Tf = 4.96 ± 0.03 K upon desolvation. Addition ofTHF to 1 leads to an enhanced Tf of 5.50 ± 0.11 K, which is attributed to an external pressure(ca 2.5 kbar) induced by the THF solvent that does not occur for the nitrile-based solvents.The desolvated materials exhibit a small frequency dependence in the ac susceptibility,'(T,f). This is typically an order of magnitude lower than the frequency dependence for thesolvated species, which is indicative of enhanced glassiness and disorder.