Details

Autor(en) / Beteiligte

• Tiliakos, Manolis
• Katsoulakou, Eugenia
• Terzis, Aris
• Raptopoulou, Catherine
• Cordopatis, Paul
• Manessi-Zoupa, Evy

Titel

The dipeptide H-Aib- l-Ala-OH ligand in copper(II) chemistry: Variation of product identity as a function of pH

Ist Teil von

• Inorganic chemistry communications, 2005-12, Vol.8 (12), p.1085-1089

Ort / Verlag

Elsevier B.V

Erscheinungsjahr

2005

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• The reaction between Cu(II) sources and the dipeptide H-Aib- l-Ala-OH (LH) is pH-dependent. In the “low pH” 3D coordination polymer {[CuClL](H 2O) 2.5} n , the monoanionic dipeptide behaves as a tridentate bridging N(amino), O(peptide), O(carboxylate) ligand, while the dianionic dipeptide exhibits the tetradentate bridging N(amino), N(peptide), O(carboxylate), O′ carboxylate behaviour in the “higher pH” 1D complex {[Cu(H −1L)(EtOH)](EtOH)} n . A systematic investigation of the influence of “pH” on the product identity from the Cu II/H-Aib- l-Ala-OH (LH) reaction system is described, where H-Aib- l-Ala-OH is α-aminoisobutyryl- l-alanine. The pH variation has led to the synthesis of two discrete complexes, the structures of which have been determined by single-crystal X-ray crystallography. The “low pH” complex {[CuClL](H 2O) 2.5} n ( 1) is a 3D coordination polymer, in which the dipeptide monoanion L − behaves as a η 1:η 1:η 1:μ 2 ligand binding one Cu II atom through its amino nitrogen and neutral peptide oxygen, and an adjacent Cu II atom through one of its carboxylate oxygen. The “higher pH” complex {[Cu(H −1L)(EtOH)](EtOH)} n ( 2) is a chain (1D) compound, in which the dipeptide dianion H −1L 2− uses its amino nitrogen, deprotonated peptide nitrogen and both carboxylate oxygens to bridge two metal centres.