FcTp(R) (R = super(i)Pr or super(t)Bu): third-generation ferrocenyl scorpionates

• Published in: Acta crystallographica. Section C, Structural chemistry Structural chemistry, 2016-11, Vol.72 (11), p.813-818
• Main Authors: Sirianni, Eric R, Cummins, Daniel C, Yap, Glenn PA, Theopold, Klaus H
• Format: Article
• Language: English
• Subjects: Benzene; Boron; Electronics; Halides; Ligands; Pyrazole; Steric effects; Synthesis
• ISSN: 2053-2296; 2053-2296
• DOI: 10.1107/S205322961601202X

Scorpionate (or trispyrazolylborate) ligands have seen much structural variation due to the relative ease of modifying their electronic and steric effects. Second-generation scorpionates were created by increasing the bulk in the 3-position of the pyrazole (pz) ring. A new class of third-generation scorpionates was obtained by modifying the remaining boron substituent. A series of thallium(I) and cobalt(II) complexes of the ferrocenyltris(3-R-pyrazolyl)borate ligand [FcTp super(R); R = isopropyl ( super(i)Pr) or tert-butyl ( super(t)Bu)] have been synthesized in order to expand the range of redox-active third-generation scorpionates. These are [ferrocenyltris(3-tert-butylpyrazol-1-yl- Kappa N super(2))bora to]thallium(I), [FeTl(C sub(5)H sub(5))(C sub(26)H sub(37)BN sub(6))], [ferrocenyltris(3-isopropylpyrazol-1-yl- Kappa N super(2))borato]th allium(I), [FeTl(C sub(5)H sub(5))(C sub(23)H sub(31)BN sub(6))], chlorido[ferrocenyltris(3-tert-butylpyrazol-1-yl- Kappa N super(2)) borato]cobalt(I I), [CoFe(C sub(5)H sub(5))(C sub(26)H sub(37)BN sub(6))Cl], [ferrocenyltris(3-tert-butylpyrazol-1-yl- Kappa N super(2))bora to]iodidocobalt(II) benzene disolvate, [CoFe(C sub(5)H sub(5))(C sub(26)H sub(37)BN sub(6))I].2C sub(6)H sub(6), and [ferrocenyltris(3-isopropylpyrazol-1-yl- Kappa N super(2))borato]io didocobalt(II), [CoFe(C sub(5)H sub(5))(C sub(23)H sub(31)BN sub(6))I]. The structures demonstrate that the metal coordination site can easily be modified by using bulkier substituents at the pz 3-position. Thallium(I) and cobalt(II) halide complexes of the ferrocenyltris(3-R-pyrazolyl)borate ligand (FcTp super(R), with R = super(i)Pr or super(t)Bu) have been synthesized and their structural characteristics determined to expand the range of redox-active third-generation scorpionates.