Response to steric constraint in azacryptate and related complexes of iron-(II) and -(III)

被引:44
作者
Deeney, FA [1 ]
Harding, CJ
Morgan, GG
McKee, V
Nelson, J
Teat, SJ
Clegg, W
机构
[1] Natl Univ Ireland Univ Coll Cork, Dept Phys, Cork, Ireland
[2] Open Univ, Dept Chem, Milton Keynes MK7 6AA, Bucks, England
[3] Queens Univ Belfast, Sch Chem, Belfast BT9 5AG, Antrim, North Ireland
[4] CLRC, Daresbury Lab, Warrington WA4 4AD, Cheshire, England
[5] Univ Newcastle Upon Tyne, Dept Chem, Newcastle Upon Tyne NE1 7RU, Tyne & Wear, England
来源
JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS | 1998年 / 11期
关键词
D O I
10.1039/a801046c
中图分类号
O61 [无机化学];
学科分类号
070301 ; 081704 ;
摘要
Iron(II) cryptates, where the Fe-II is in the high-spin S = 2 electronic configuration, even with six sp(2) N-donors, and iron(III) cryptates adopting the intermediate spin S = 3/2 state have been prepared. The structure of a high-spin iron(II) cryptate utilising six sp(2) N-donors shows long metal-ligand distances which effectively destabilise the low-spin (1)A(g) configuration. Comparison is made between iron(III) cryptates, a less sterically constrained podand complex of the same donor set, and analogous N4O2- polychelates, which are respectively intermediate-, high- and low-spin or S = 5/2 <-> S = 1/2 spin crossover systems. The Mossbauer spectra of the iron(III) cryptates and analogous pedate are remarkably similar, despite their different spin states, suggesting covalency in the pedate binding. The crystal structure of the pedate supports this conclusion, as the iron-ligand donor distances are short for high-spin Fe-III.
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页码:1837 / 1843
页数:7
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