TY - JOUR
T1 - Synthesis and characterization of copper(i), copper(ii), zinc(ii), cobalt(ii), and iron(ii) complexes of a chelating ligand derived from 2, 6-diacetylpyridine and l-histidine. oxygenation of the copper(i), cobalt(ii), and iron(ii) complexes. crystal structure of the zinc(ii) complex
AU - Casella, Luigi
AU - Silver, Michael E.
AU - Ibers, James A
PY - 1984/1/1
Y1 - 1984/1/1
N2 -
The synthesis and characterization of the perchlorate salts of the copper(I), copper(II), zinc(II), cobalt(II), and iron(II) complexes of 2, 6-bis[1-((1-(carboxymethyl)-2-imidazol-4-ylethyl)imino)ethyl]pyridine = L-bisp (the condensation product of 2, 6-diacetylpyridine with two molecules of the methyl ester of the amino acid L-histidine) along with an X-ray structural investigation of the zinc(II) complex, [Zn(L-bisp)][ClO
4
]
2
, are reported. The zinc complex crystallizes in the space group D
2
4
-P2
1
2
1
2
1
four formula units in a cell of dimensions (at-152 °C) a = 28.872 (18) Å, b = 9.567 (6) Å, and c = 10.344 (6) Å. The structure was described by 406 variable parameters, and at convergence the values for R and R
w
(on F
2
, 5784 data) were 0.060 and 0.090 for the L,L enantiomer. The zinc atom is bonded to five nitrogen atoms and displays a coordination geometry intermediate between a trigonal bipyramid and a square pyramid. Both of the six-membered amino acid chelate rings of the L-bisp ligand adopt the λ configuration. The Cu(I) complex is inert to dioxygen in the solid state but does react with O
2
at ambient conditions in dry acetonitrile. The reaction is complete in ca. 1 h and can be slowly reversed by degassing (N
2
) and gentle heating, the degree of reversibility being about 80% for each of several oxy-deoxy cycles. Spectral evidence indicates the oxygenated product is not simply [Cu(L-bisp)] [ClO
4
]
2
and that the L-bisp ligand remains intact. The stoichiometry of the oxygenation reaction is 0.5 mol (±10%) of O
2
/mol of copper. Both the Fe(II) and the Co(II) complexes of L-bisp show low or no reactivity to dioxygen in dry acetonitrile or dimethylformamide. However, pyridine solutions of these two complexes do react irreversibly with O
2
at ambient conditions and, in both cases, IR evidence is indicative of concomitant ligand oxidation.
AB -
The synthesis and characterization of the perchlorate salts of the copper(I), copper(II), zinc(II), cobalt(II), and iron(II) complexes of 2, 6-bis[1-((1-(carboxymethyl)-2-imidazol-4-ylethyl)imino)ethyl]pyridine = L-bisp (the condensation product of 2, 6-diacetylpyridine with two molecules of the methyl ester of the amino acid L-histidine) along with an X-ray structural investigation of the zinc(II) complex, [Zn(L-bisp)][ClO
4
]
2
, are reported. The zinc complex crystallizes in the space group D
2
4
-P2
1
2
1
2
1
four formula units in a cell of dimensions (at-152 °C) a = 28.872 (18) Å, b = 9.567 (6) Å, and c = 10.344 (6) Å. The structure was described by 406 variable parameters, and at convergence the values for R and R
w
(on F
2
, 5784 data) were 0.060 and 0.090 for the L,L enantiomer. The zinc atom is bonded to five nitrogen atoms and displays a coordination geometry intermediate between a trigonal bipyramid and a square pyramid. Both of the six-membered amino acid chelate rings of the L-bisp ligand adopt the λ configuration. The Cu(I) complex is inert to dioxygen in the solid state but does react with O
2
at ambient conditions in dry acetonitrile. The reaction is complete in ca. 1 h and can be slowly reversed by degassing (N
2
) and gentle heating, the degree of reversibility being about 80% for each of several oxy-deoxy cycles. Spectral evidence indicates the oxygenated product is not simply [Cu(L-bisp)] [ClO
4
]
2
and that the L-bisp ligand remains intact. The stoichiometry of the oxygenation reaction is 0.5 mol (±10%) of O
2
/mol of copper. Both the Fe(II) and the Co(II) complexes of L-bisp show low or no reactivity to dioxygen in dry acetonitrile or dimethylformamide. However, pyridine solutions of these two complexes do react irreversibly with O
2
at ambient conditions and, in both cases, IR evidence is indicative of concomitant ligand oxidation.
UR - http://www.scopus.com/inward/record.url?scp=0001554663&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0001554663&partnerID=8YFLogxK
U2 - 10.1021/ic00178a022
DO - 10.1021/ic00178a022
M3 - Article
AN - SCOPUS:0001554663
VL - 23
SP - 1409
EP - 1418
JO - Inorganic Chemistry
JF - Inorganic Chemistry
SN - 0020-1669
IS - 10
ER -