TY - JOUR
T1 - Complexes of cobalt(III) with phenolate-containing polydentate ligands and bovine serum apo-transferrin
T2 - Towards creating spectroscopic models for cobalt(III)-tyrosinate interactions
AU - Shongwe, Musa S.
AU - Al-Hatmi, Said K M
AU - Marques, Helder M.
AU - Smith, Rachel
AU - Nukada, Ryoji
AU - Mikuriya, Masahiro
PY - 2002
Y1 - 2002
N2 - Reaction of each member of a series of variously substituted N-(2-hydroxybenzyl)glycinate (hbg
2-) ligands [5-bromo- (5-Br-hbg
2-); 5-chloro- (5-Cl-hbg
2-); 3,5-dichloro- (3,5-Cl
2-hbg
2-); 5-chloro-3-methyl- (5,3-Cl,Me-hbg
2-); and 3,5-dimethyl- (3,5-Me
2-hbg
2-)] with cobalt(II) in stoichiometric amounts under ambient conditions afforded the Co
III complex anions of the general formulatrans,trans,trans-[Co(hbg)
2]
-. Single-crystal X-ray analyses of [C
5H
10NH
2]-trans,trans,trans-[Co(3,5-Cl
2-hbg)
2]3 and [C
5H
10NH
2]-trans,trans,trans-[Co(3,5-Me
2-hbg)
2]5 {[C
5H
10- NH
2] piperidinium counter ion} have revealed similar structural motifs of these compounds. Each of the crystal structures shows two non-equivalent complex anions in the unit cell connected through hydrogen bondingvia the piperidinium cation. The two hbg
2- ligands in each complex ion are arranged facially around the cobalt(III) ion and each ligand employs a phenolate oxygen, an amine nitrogen and a carboxylate oxygen to form a distorted octahedral geometry with C
i symmetry. These compounds (1-5) serve as spectroscopic models for the interaction of cobalt(III) with tyrosinate ligands. The electronic spectrum of the compound [C
5H
10NH
2]-trans,trans,trans-[Co(5,3-Cl, Me-hbg)
2]4 bears a striking resemblance to that of the complex of cobalt(III) with bovine serum transferrin, [Co
2BTf]. In contrast to previous studies on the spectroscopy of the transferrins, one of the two ligand-field transitions expected to occur in [Co
2BTf] is evident in the electronic spectrum of this derivative of bovine serum transferrin in vitro. One of the fascinating characteristics of thetrans,trans,trans-[Co(hbg)
2]
- model system is the solvent dependence of the optical spectra.
AB - Reaction of each member of a series of variously substituted N-(2-hydroxybenzyl)glycinate (hbg
2-) ligands [5-bromo- (5-Br-hbg
2-); 5-chloro- (5-Cl-hbg
2-); 3,5-dichloro- (3,5-Cl
2-hbg
2-); 5-chloro-3-methyl- (5,3-Cl,Me-hbg
2-); and 3,5-dimethyl- (3,5-Me
2-hbg
2-)] with cobalt(II) in stoichiometric amounts under ambient conditions afforded the Co
III complex anions of the general formulatrans,trans,trans-[Co(hbg)
2]
-. Single-crystal X-ray analyses of [C
5H
10NH
2]-trans,trans,trans-[Co(3,5-Cl
2-hbg)
2]3 and [C
5H
10NH
2]-trans,trans,trans-[Co(3,5-Me
2-hbg)
2]5 {[C
5H
10- NH
2] piperidinium counter ion} have revealed similar structural motifs of these compounds. Each of the crystal structures shows two non-equivalent complex anions in the unit cell connected through hydrogen bondingvia the piperidinium cation. The two hbg
2- ligands in each complex ion are arranged facially around the cobalt(III) ion and each ligand employs a phenolate oxygen, an amine nitrogen and a carboxylate oxygen to form a distorted octahedral geometry with C
i symmetry. These compounds (1-5) serve as spectroscopic models for the interaction of cobalt(III) with tyrosinate ligands. The electronic spectrum of the compound [C
5H
10NH
2]-trans,trans,trans-[Co(5,3-Cl, Me-hbg)
2]4 bears a striking resemblance to that of the complex of cobalt(III) with bovine serum transferrin, [Co
2BTf]. In contrast to previous studies on the spectroscopy of the transferrins, one of the two ligand-field transitions expected to occur in [Co
2BTf] is evident in the electronic spectrum of this derivative of bovine serum transferrin in vitro. One of the fascinating characteristics of thetrans,trans,trans-[Co(hbg)
2]
- model system is the solvent dependence of the optical spectra.
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M3 - Article
AN - SCOPUS:0036026807
SP - 4064
EP - 4069
JO - Dalton Transactions
JF - Dalton Transactions
SN - 0300-9246
IS - 21
ER -