TY - JOUR
T1 - Hydrogen-bonding interactions, geometrical selectivity and spectroscopic properties of cobalt(III) complexes with unsymmetrical tridentate amine-amidato-phenolato type ligands
AU - Mitsuhashi, Ryoji
AU - Suzuki, Takayoshi
AU - Sunatsuki, Yukinari
AU - Kojima, Masaaki
N1 - Funding Information:
This work was partly supported by a Grant-in-Aid for Challenging Exploratory Research No. 23655052 from the Ministry of Education, Culture, Sports, Science, and Technology, Japan. Appendix A
PY - 2013/4/1
Y1 - 2013/4/1
N2 - Four cobalt(III) complexes with the formula of [Co(Ln)2] - bearing tridentate amine-amidato-phenolato-type ligands (Ln: n = 1-4) were synthesized. All of the complexes were characterized by 1H NMR spectroscopy and X-ray analysis. The geometrical selectivity was found to depend on the flexibility of the amine-amidato chelate in combination with the planar 2-oxybenzamido 6-membered chelate; that is, the amine-amidato 5-membered chelate took the mer-type geometry, and the 6-membered chelate took the fac-type geometry. In most of the mer-type complexes, intermolecular double hydrogen bonds via amidato(O) and amino group were selectively formed between their enantiomeric pairs of mononuclear complexes. In the case of two chiral ligands {L22- = 2-amino-1-(2-oxybenzamido)propane; L32- = trans-1-amino-2-(2-oxybenzamido)cyclohexane}, [Co(L3)2]- showed diastereoselectivity while [Co(L2)2]- did not. Furthermore, PPh4[Co(L1)2] (L12- = 2-amino-1-(2-oxybenzamido)-2-methylpropane) showed an apparent solvatochromic behavior in several solvents. Although the molecular structures of [Co(L2 or L3)2]- are quite similar to that of [Co(L1) 2]-, these complexes did not exhibit such a solvatochromic behavior.
AB - Four cobalt(III) complexes with the formula of [Co(Ln)2] - bearing tridentate amine-amidato-phenolato-type ligands (Ln: n = 1-4) were synthesized. All of the complexes were characterized by 1H NMR spectroscopy and X-ray analysis. The geometrical selectivity was found to depend on the flexibility of the amine-amidato chelate in combination with the planar 2-oxybenzamido 6-membered chelate; that is, the amine-amidato 5-membered chelate took the mer-type geometry, and the 6-membered chelate took the fac-type geometry. In most of the mer-type complexes, intermolecular double hydrogen bonds via amidato(O) and amino group were selectively formed between their enantiomeric pairs of mononuclear complexes. In the case of two chiral ligands {L22- = 2-amino-1-(2-oxybenzamido)propane; L32- = trans-1-amino-2-(2-oxybenzamido)cyclohexane}, [Co(L3)2]- showed diastereoselectivity while [Co(L2)2]- did not. Furthermore, PPh4[Co(L1)2] (L12- = 2-amino-1-(2-oxybenzamido)-2-methylpropane) showed an apparent solvatochromic behavior in several solvents. Although the molecular structures of [Co(L2 or L3)2]- are quite similar to that of [Co(L1) 2]-, these complexes did not exhibit such a solvatochromic behavior.
KW - Amine-amidato type ligand
KW - Diastereoselectivity
KW - Double hydrogen bonds
KW - Geometrical isomers
KW - Solvatochromism
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U2 - 10.1016/j.ica.2013.01.011
DO - 10.1016/j.ica.2013.01.011
M3 - Article
AN - SCOPUS:84875470907
SN - 0020-1693
VL - 399
SP - 131
EP - 137
JO - Inorganica Chimica Acta
JF - Inorganica Chimica Acta
ER -