TY - JOUR
T1 - Cobalt cage complexes with N3S3 donor sets and differing cavity sizes
T2 - A novel macrobicyclic cage with a contracted cap
AU - Osvath, Peter
AU - Sargeson, Alan M.
AU - McAuley, Alex
AU - Mendelez, Rosa E.
AU - Subramanian, S.
AU - Zaworotko, Michael J.
AU - Broge, Louise
PY - 1999
Y1 - 1999
N2 - Treatment of the cobalt(III) complex of the hexadentate tripodal N3N3 ligand ten (4,4′,4″-ethylidynetris(3-thiabutan1-amine) with propanal and paraformaldehyde under basic conditions, followed by borohydride reduction and reoxidation of the metal center, leads largely to the encapsulated (red) metal complex cation [Co(Me2-N3S3sar)]3+ (Me2-N3S3sar = 1,8-dimemyl-3,13,16-trithia-6,10,19-triazabicyclo[6.6.6]icosane). Unexpectedly, significant amounts of the homologous (yellow) complex cation [Co(Me2-N3S3absar)]3+ (Mez-N3S3absar = l,8-dimethyl-3,13,16-trithia-6,10,19-triazabicyclo[6.6.5]nonadecane) were also obtained. This macrobicyclic complex has a contracted cavity resulting from a cap containing one fewer methylene units than Me2-N3S3sar. The structures of both cobalt(III) complexes have been determined by X-ray crystallography. [Co(Me2-N3S3sar)]Ci·ZnCl 4·H2O crystallizes in the cubic space group P213 with Z = 4, a = 13.9683(11) Å. [Co(Me2-N3S3absar)](ClO4) 3·0.5CH3CN·0.5H2O crystallizes in the triclinic space group P1̄ with Z = 4, a = 12.036(4) Å, b = 15.932(9) Å, c = 17.212(14) Å, α = 64.93(7)̊, β= 72.77(5)°, γ = 88.91(7)°. The surprising structural rearrangement is examined, along with the spectral and redox properties of both cobalt complexes. The influence of the reduced cavity size in the absar type cage is reflected in a shift of the bands in the electronic spectrum of both the cobalt(II) and cobalt(III) complexes to higher energy, and a more negative value for the Co(III/II) redox potential. The demetalation of the complexes is also described.
AB - Treatment of the cobalt(III) complex of the hexadentate tripodal N3N3 ligand ten (4,4′,4″-ethylidynetris(3-thiabutan1-amine) with propanal and paraformaldehyde under basic conditions, followed by borohydride reduction and reoxidation of the metal center, leads largely to the encapsulated (red) metal complex cation [Co(Me2-N3S3sar)]3+ (Me2-N3S3sar = 1,8-dimemyl-3,13,16-trithia-6,10,19-triazabicyclo[6.6.6]icosane). Unexpectedly, significant amounts of the homologous (yellow) complex cation [Co(Me2-N3S3absar)]3+ (Mez-N3S3absar = l,8-dimethyl-3,13,16-trithia-6,10,19-triazabicyclo[6.6.5]nonadecane) were also obtained. This macrobicyclic complex has a contracted cavity resulting from a cap containing one fewer methylene units than Me2-N3S3sar. The structures of both cobalt(III) complexes have been determined by X-ray crystallography. [Co(Me2-N3S3sar)]Ci·ZnCl 4·H2O crystallizes in the cubic space group P213 with Z = 4, a = 13.9683(11) Å. [Co(Me2-N3S3absar)](ClO4) 3·0.5CH3CN·0.5H2O crystallizes in the triclinic space group P1̄ with Z = 4, a = 12.036(4) Å, b = 15.932(9) Å, c = 17.212(14) Å, α = 64.93(7)̊, β= 72.77(5)°, γ = 88.91(7)°. The surprising structural rearrangement is examined, along with the spectral and redox properties of both cobalt complexes. The influence of the reduced cavity size in the absar type cage is reflected in a shift of the bands in the electronic spectrum of both the cobalt(II) and cobalt(III) complexes to higher energy, and a more negative value for the Co(III/II) redox potential. The demetalation of the complexes is also described.
UR - http://www.scopus.com/inward/record.url?scp=0000759791&partnerID=8YFLogxK
U2 - 10.1021/ic981380g
DO - 10.1021/ic981380g
M3 - Article
SN - 0020-1669
VL - 38
SP - 3634
EP - 3643
JO - Inorganic Chemistry
JF - Inorganic Chemistry
IS - 16
ER -