Structural Characterization of Bis[N-(o-Hydroxybenzyl-(S)-Leucinato)]cobaltate(III) Anion. Tyrosine-Like Model Complex with Structurally Inequivalent Chelate Rings

• Published in: Collection of Czechoslovak chemical communications Vol. 61; no. 12; pp. 1754 - 1766
• Main Authors: Pakhomova, Svetlana, Ondráček, Jan, Jursík, František
• Format: Journal Article
• Language: English
• Published: 1996
• ISSN: 0010-0765; 1212-6950
• DOI: 10.1135/cccc19961754

[Co(NH
3
)
4
(H
2
O)
2
]OH . [Co(ohb-(
S
)-Leu)
2
] . 2 H
2
O (ohb,
o
-hydroxybenzyl) was characterized by single-crystal X-ray diffraction which shows that both ligands in the [Co(ohb-(
S
)-Leu)
2
]
-
anion assume
facial
coordination mode with all donor atoms
trans
to each other, proposed on the basis of UV-VIS and
13
C NMR spectroscopy, with
R,S
configuration of secondary N atoms. Compound crystallizes in the tetragonal space group
I4
1
with unit cell dimensions
a
= 22.173(7),
c
= 13.270(2) Å, V = 6 524 Å
3
,
Z
= 4. Structural data show that both ligands are not equivalent. Bond angles and bond lengths depend on whether secondary N atoms adopt
R
or
S
configuration. The average bond lengths are shorter when the ohb-(
S
)-Leu ligand coordinates with (N)
R
configuration.