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Oxidative Stannylation with K 6 Sn 2 Se 6 /SnCl 2 : Synthesis and Crystal Structures of SnCl 3 ‐Substituted pseudo ‐Tetrahedral Cobalt(III) Complexes
Author(s) -
Dehnen Stefanie,
Zimmermann Christian
Publication year - 2000
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/1099-0682(200007)2000:7<1471::aid-ejic1471>3.0.co;2-a
Subject(s) - chemistry , oxidizing agent , redox , steric effects , cobalt , molecule , crystallography , electron transfer , oxidation state , crystal structure , stereochemistry , photochemistry , inorganic chemistry , catalysis , organic chemistry
The ternary Zintl phase K 6 Sn 2 Se 6 was recently shown to mildly oxidize Cp*‐ligated Co II complexes, although Sn in the formal +III oxidation state usually tends to be a reducing species. Depending on the reaction conditions, different ratios of Co II and Co III were observed within the product molecules. Cyclovoltammetric investigations indicated that reversible electron transfer occurred between some of the isolated molecules synthesized that way. In order to study the redox behavior of the oxidizing Sn III species in the reaction system, large excesses of Sn II were added to the solvent THF. A suppression of the Co II → Co III transition was expected if the oxidation was reversible. Herein we report the synthesis and crystal structures of [Co 2 (μ‐Cl) 3 (thf) 6 ][CoClCp*(SnCl 3 ) 2 ] ( 1 ) and [Li(thf) 4 ][CoCp*(SnCl 3 ) 3 ] ( 2 ) formed from reactions of [CoClCp*] 2 with K 6 Sn 2 Se 6 in the presence of SnCl 2 in THF. The results show that oxidation could not be inhibited, indicative of irreversible redox mechanisms. Additionally, one observes the formal insertion of SnCl 2 units in Co−Cl bonds. For completion of the 18‐electron configuration, the Cp*Co III 14‐electron fragment forms sterically strained anionic structures that may in the future be relevanct as precursors for the formation of Cp*Co‐coated heteroatomic aggregates. Furthermore, the cation in 1 is one of the few examples of threefold µ 2 ‐bridged binuclear Co II complexes.