Structure and properties of an oxalato-bridged dinickel(II) complex with a tetraazamacrocycle bearing an aminomethyl pendant arm, 5-aminomethyl-5R(S),12R(S)-dimethyl-1,4,8,11-tetraazacyclotetradecane

• Published in: Journal of coordination chemistry 2004-05, Vol.57 (7), p.543-551
• Main Authors: Mochizuki, Katsura, Numata, Yasunori, Kitazawa, Yoshiko, Ishii, Atushi
• Format: Article
• Language: English
• Subjects: Aminomethyl pendant arm; Folded macrocyclic ligand; Oxalato-bridged dinickel(II) complex
• ISSN: 0095-8972; 1029-0389
• DOI: 10.1080/00958970410001677042

The oxalato-bridged dinickel(II) complex with the title ligand, [Ni 2 (L a H) 2 (μ-ox)](ClO 4 ) 2 ·2H 2 O (1), was prepared and its structure was determined by X-ray crystallography, as well as that of the monomeric nickel(II) complex, [Ni(L a H)ox]ClO 4 ·3H 2 O (2). In Complexes 1 and 2, the ligand, L a , is folded along the N(4)-Ni(1)-N(11) axis. The antiferromagnetic coupling between the two nickel(II) centers in 1 was revealed and the coupling constant, J = −17.4 cm −1 , and g = 2.11 were estimated. It was found that the oxalato-bridged dimer 1 was readily converted to the mononuclear cis-nickel(II) complex [NiL a (OH 2 )](ClO 4 ) 2 (3a), in basic aqueous solution. In [NiL a (CH 3 CN)]I 2 (3b), which was derived from 3a, the aminomethyl pendant arm is coordinated to the Ni(II) ion and L a is folded along the N(1)-Ni(1)-N(8) axis.