Template syntheses of chiral tetradentate ligands derived from L-amino acids. Structural and spectroscopic characterization of the free ligands and of their copper(II) complexes

Peter Comba, Trevor W. Hambley, Geoffrey A. Lawrance, Lisandra L. Martin, Peter Renold, K. Várnagy

Research output: Contribution to journalArticle

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Abstract

The copper(II)-directed condensation of amino acids with formaldehyde and nitroethane in basic methanol produces open-chain tetradentate ligands with a pendant nitro substituent in high yield. With optically pure L-amino acids full retention of configuration is achieved, and with racemic D/L-amino acids the condensation is fully selective, viz. only one out of three possible isomers is produced. These aspects are discussed based on 1H and 13C NMR data for the free ligands based on glycine, L-alanine, and D/L-alanine, and on the X-ray structures of the corresponding copper(II) template products, (5-methyl-5-nitro-3,7-diazanonanedioato)copper(II) 1a, [(2S,8S)-2,5,8-trimethyl-5-nitro-3,7-diazanonanedioato]copper(II) hydrate 1b and [(2R,8S)-5-methyl-5-nitro-3,7-diazanonanedioato)copper(II)] 1c respectively. Complex 1a crystallizes in the orthorhombic space group P212121, a = 6.197(1), b = 12.772(1), c = 13.717(1) Å, Z = 4; 1b crystallizes in the monoclinic space group P21, a = 9.532(2), b = 6.371(1), c = 11.832(2) Å, β = 104.89(1)°, Z = 2; 1c crystallizes in the triclinic space group P1, a = 8.015(2), b = 9.297(1), c = 9.401(2) Å, α = 80.47(1), β = 71.33(2), γ = 79.78(2)°, Z = 2. Preliminary solution spectroscopy of the copper(II) complexes indicates that the solution structures of a whole series of copper(II) condensation products with amino acids are similar to the reported X-ray structures, and all are similar to each other except for 1a which in solution is predominantly dimeric.

Original languageEnglish
Pages (from-to)277-283
Number of pages7
JournalJournal of the Chemical Society, Dalton Transactions
Issue number2
DOIs
Publication statusPublished - 1991

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Copper
Ligands
Amino Acids
Condensation
alanylglycine
X rays
Hydrates
Isomers
Alanine
Formaldehyde
Methanol
Nuclear magnetic resonance
Spectroscopy

ASJC Scopus subject areas

  • Chemistry(all)

Cite this

Template syntheses of chiral tetradentate ligands derived from L-amino acids. Structural and spectroscopic characterization of the free ligands and of their copper(II) complexes. / Comba, Peter; Hambley, Trevor W.; Lawrance, Geoffrey A.; Martin, Lisandra L.; Renold, Peter; Várnagy, K.

In: Journal of the Chemical Society, Dalton Transactions, No. 2, 1991, p. 277-283.

Research output: Contribution to journalArticle

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abstract = "The copper(II)-directed condensation of amino acids with formaldehyde and nitroethane in basic methanol produces open-chain tetradentate ligands with a pendant nitro substituent in high yield. With optically pure L-amino acids full retention of configuration is achieved, and with racemic D/L-amino acids the condensation is fully selective, viz. only one out of three possible isomers is produced. These aspects are discussed based on 1H and 13C NMR data for the free ligands based on glycine, L-alanine, and D/L-alanine, and on the X-ray structures of the corresponding copper(II) template products, (5-methyl-5-nitro-3,7-diazanonanedioato)copper(II) 1a, [(2S,8S)-2,5,8-trimethyl-5-nitro-3,7-diazanonanedioato]copper(II) hydrate 1b and [(2R,8S)-5-methyl-5-nitro-3,7-diazanonanedioato)copper(II)] 1c respectively. Complex 1a crystallizes in the orthorhombic space group P212121, a = 6.197(1), b = 12.772(1), c = 13.717(1) {\AA}, Z = 4; 1b crystallizes in the monoclinic space group P21, a = 9.532(2), b = 6.371(1), c = 11.832(2) {\AA}, β = 104.89(1)°, Z = 2; 1c crystallizes in the triclinic space group P1, a = 8.015(2), b = 9.297(1), c = 9.401(2) {\AA}, α = 80.47(1), β = 71.33(2), γ = 79.78(2)°, Z = 2. Preliminary solution spectroscopy of the copper(II) complexes indicates that the solution structures of a whole series of copper(II) condensation products with amino acids are similar to the reported X-ray structures, and all are similar to each other except for 1a which in solution is predominantly dimeric.",
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T1 - Template syntheses of chiral tetradentate ligands derived from L-amino acids. Structural and spectroscopic characterization of the free ligands and of their copper(II) complexes

AU - Comba, Peter

AU - Hambley, Trevor W.

AU - Lawrance, Geoffrey A.

AU - Martin, Lisandra L.

AU - Renold, Peter

AU - Várnagy, K.

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N2 - The copper(II)-directed condensation of amino acids with formaldehyde and nitroethane in basic methanol produces open-chain tetradentate ligands with a pendant nitro substituent in high yield. With optically pure L-amino acids full retention of configuration is achieved, and with racemic D/L-amino acids the condensation is fully selective, viz. only one out of three possible isomers is produced. These aspects are discussed based on 1H and 13C NMR data for the free ligands based on glycine, L-alanine, and D/L-alanine, and on the X-ray structures of the corresponding copper(II) template products, (5-methyl-5-nitro-3,7-diazanonanedioato)copper(II) 1a, [(2S,8S)-2,5,8-trimethyl-5-nitro-3,7-diazanonanedioato]copper(II) hydrate 1b and [(2R,8S)-5-methyl-5-nitro-3,7-diazanonanedioato)copper(II)] 1c respectively. Complex 1a crystallizes in the orthorhombic space group P212121, a = 6.197(1), b = 12.772(1), c = 13.717(1) Å, Z = 4; 1b crystallizes in the monoclinic space group P21, a = 9.532(2), b = 6.371(1), c = 11.832(2) Å, β = 104.89(1)°, Z = 2; 1c crystallizes in the triclinic space group P1, a = 8.015(2), b = 9.297(1), c = 9.401(2) Å, α = 80.47(1), β = 71.33(2), γ = 79.78(2)°, Z = 2. Preliminary solution spectroscopy of the copper(II) complexes indicates that the solution structures of a whole series of copper(II) condensation products with amino acids are similar to the reported X-ray structures, and all are similar to each other except for 1a which in solution is predominantly dimeric.

AB - The copper(II)-directed condensation of amino acids with formaldehyde and nitroethane in basic methanol produces open-chain tetradentate ligands with a pendant nitro substituent in high yield. With optically pure L-amino acids full retention of configuration is achieved, and with racemic D/L-amino acids the condensation is fully selective, viz. only one out of three possible isomers is produced. These aspects are discussed based on 1H and 13C NMR data for the free ligands based on glycine, L-alanine, and D/L-alanine, and on the X-ray structures of the corresponding copper(II) template products, (5-methyl-5-nitro-3,7-diazanonanedioato)copper(II) 1a, [(2S,8S)-2,5,8-trimethyl-5-nitro-3,7-diazanonanedioato]copper(II) hydrate 1b and [(2R,8S)-5-methyl-5-nitro-3,7-diazanonanedioato)copper(II)] 1c respectively. Complex 1a crystallizes in the orthorhombic space group P212121, a = 6.197(1), b = 12.772(1), c = 13.717(1) Å, Z = 4; 1b crystallizes in the monoclinic space group P21, a = 9.532(2), b = 6.371(1), c = 11.832(2) Å, β = 104.89(1)°, Z = 2; 1c crystallizes in the triclinic space group P1, a = 8.015(2), b = 9.297(1), c = 9.401(2) Å, α = 80.47(1), β = 71.33(2), γ = 79.78(2)°, Z = 2. Preliminary solution spectroscopy of the copper(II) complexes indicates that the solution structures of a whole series of copper(II) condensation products with amino acids are similar to the reported X-ray structures, and all are similar to each other except for 1a which in solution is predominantly dimeric.

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