Partial and Gradual Hydrolysis of 2,2′-Biimidazoline upon Coordination to Metal Ions, yielding New Chelating Ligands - Synthesis, Characterization and X-ray Structure of two Examples with Cobalt(III) and Copper(II)

• Published in: Zeitschrift für anorganische und allgemeine Chemie (1950) 2004-09, Vol.630 (11), p.1594-1598
• Main Authors: van Albada, Gerard A., Mohamadou, Aminou, Manotti Lanfredi, Anna Maria, Mutikainen, Ilpo, Turpeinen, Urho, Ugozzoli, Franco, Reedijk, Jan
• Format: Article
• Language: English
• Subjects: Chemical Sciences; Cobalt; Coordination chemistry; Copper; Crystal structures; Hydrolysis
• ISSN: 0044-2313; 1521-3749
• DOI: 10.1002/zaac.200400210

The synthesis, a full structural characterization of two transition‐metal compounds obtained by in‐situ hydrolysis and partly hydrolysis of the ligand 2, 2′‐biimidazoline (abbreviated as biz) is reported. When the biz ligand is completely hydrolysed the compound, N, N′‐bis(2‐aminoethyl)oxamide (abbreviated as H2oxen) is obtained, while the partial hydrolysis results in the ligand N‐(2‐aminoethyl)imidazoline‐2‐carboxamide (abbreviated as Hoxim). The CoIII ion in the mononuclear CoIII compound, [Co(biz)(oxim)(NCS)](ClO4)(C2H5OH)1/6(H2O)1/6 (1), has an octahedral coordination consisting of 6 nitrogen atoms with a distance varying from 1.889(6) to 1.950(5) Å. Two nitrogen atoms originating from a biz molecule, 3 nitrogen atoms are from the oxim ligand and one nitrogen is from the thiocyanate anion. Each CuII ion in the dinuclear CuII compound, [Cu2(H2oxen)(oxim)2(C2H5OH)2] (ClO4)2 (2), has a slightly distorted square‐pyramidal structure of which the basal plain consists of3 nitrogen atoms of the oxim ligand and one nitrogen atom of the H2oxen ligand, which is used as a “spacer” connecting the second CuII atom, with Cu‐N distances which vary from 1.944(2) to 2.037(2) Å. The apical position is formed by the oxygen atom of a semi‐coordinating ethanol molecule with a Cu‐O distance of 2.446(2) Å. The compounds are characterized by elemental analysis, ligand field, infrared and, for the CuII ion, also by EPR spectroscopy. Teilweise und graduelle Hydrolyse von 2, 2′‐Biimidazolin nach Koordination an Metallionen als Weg zu neuen Chelatliganden ‐ Synthese, Charakterisierung und Kristallstrukturen zweier Beispiele mit Cobalt(III) und Kupfer(II) Die Synthese und die strukturelle Charakterisierung zweier Übergangsmetall‐Verbindungen, die durch in‐situ‐Hydrolyse und partielle Hydrolyse des 2, 2′‐Biimidazolin‐Liganden (abgekürzt als biz) werden beschrieben. Vollständige Hydrolyse des biz‐Liganden führt zu N, N′‐bis(2‐aminoethyl)oxamid (abgekürzt als H2oxen), während teilweise Hydrolyse den Liganden N‐(2‐aminoethyl)imidazolin‐2‐carboxamid (abgekürzt als Hoxim) liefert. Das CoIII‐Ion in dem einkernigen Komplex [Co(biz)(oxim)(NCS)](ClO4)(C2H5OH)1/6(H2O)1/6 (1) ist oktaedrisch von 6 Stickstoffatomen umgeben mit Abständen zwischen 1.889(6) und 1.950(5) Å. Zwei Stickstoffatome stammen von dem biz‐Molekül, drei vom Oxin‐Liganden und eines vom Thiocyanation. Die CuII‐Ionen in der zweikernigen Verbindung [Cu2(H2oxen)(oxim)2(C2H5OH)2](ClO4)2 (2) haben leicht verzerrte quadratisch‐pyr