THE (MU-OXO)BIS[TRICHLOROFERRATE(III)] DIANION REVISITED
THE (MU-OXO)BIS[TRICHLOROFERRATE(III)] DIANION REVISITED
复制标题
DOI：
10.1021/ic00057a006
复制
发表时间：
1993-03-03
影响因子：
4.6
通讯作者：
SCHRADER, B
中科院分区：
文献类型：
--
作者：
HASELHORST, G;WIEGHARDT, K;SCHRADER, B
从已发表的11种含(Mu-oxo)双[三氯铁酸盐(III)]阴离子的盐的晶体结构测定中，可以明显看出该阴离子在固体状态下的下列结构特征：(I)结构取决于相应的反阳离子的性质。(Ii)Fe-O-Fe键角在146.5度至170.8度的范围内；线性Fe-O-Fe单元尚未得到实验验证。(3)Fe-O(氧)键距离在实验误差范围内相同(1.756埃)。(4)Cl3FeO单元的几何构型近似为四面体，但对称性为C(S)；在C3中的描述，对称性在许多情况下是不合适的。(V)两个共享角点的四面体根据反面的性质而采用不同的构象。测定了[Ph_4P]_2[Fe_2Cl6O]的晶体结构：空间群P_1bar，a=9.847(3)埃，b=12.953(5)埃，c=21.099(5)埃，a=85.12(3)度，β=76.45(2)度，伽马=67.70(3)度，Z=2。并在2.7-295K温度范围内测量了它们的磁化率，在所有情况下都建立了铁离子之间的反铁磁交换耦合。与[Fe2Cl6O]2-阴离子的实际结构无关，耦合常数J=112+/-5 cm-1(H=-2JS1.S2；S1=S2=5/2)。在我们测量的实验精度内，还没有检测到分子内反铁磁耦合的角度依赖关系。
From 11 published crystal structure determinations of salts containing the (mu-oxo)bis[trichloroferrate(III)] dianion the following structural features of the anion in the solid state are evident: (i) The structure is dependent on the nature of the respective countercation. (ii) The Fe-O-Fe bond angle spans a range from 146.5 to 170.8-degrees; a linear Fe-O-Fe unit has not been experimentally verified. (iii) The Fe-O(oxo) bond distances are within experimental error identical (1.756 angstrom). (iv) The geometry of the Cl3FeO unit is approximately tetrahedral, but the symmetry is C(s); description in C3, symmetry is in many instances not appropriate. (v) The two corner-sharing tetrahedra adopt different conformations depending on the nature of the countercation. The crystal structure of [Ph4P]2[Fe2Cl6O] has been determined: space group P1BAR, a = 9.847(3) angstrom, b = 12.953(5) angstrom, c = 21.099(5) angstrom, a = 85.12(3)-degrees, beta = 76.45(2)-degrees, gamma = 67.70(3)-degrees, and Z = 2. Five crystallographically well-characterized salts with Fe-O-Fe angles ranging from 148.1 to 170.8-degrees have been investigated by infrared and Raman spectroscopy, and their magnetic susceptibilities have been measured in the temperature range 2.7-295 K. Antiferromagnetic exchange coupling between the ferric ions has been established in all cases. The coupling constant J was found to be 112 +/- 5 cm-1 (H = -2JS1.S2; S1 = S2 = 5/2) irrespective of the actual structure of the [Fe2Cl6O]2- anion. An angle dependence of the intramolecular antiferromagnetic coupling has not been detected within the experimental accuracy of our measurements.