A family of polynuclear cobalt complexes upon employment of an indeno-quinoxaline based oxime ligand

Canaj, A. B. , Nodaraki, L. E., Ślepokura, K., Siczek, M., Tzimopoulos, D. I., Lis, T. and Milios, C. J. (2014) A family of polynuclear cobalt complexes upon employment of an indeno-quinoxaline based oxime ligand. RSC Advances, 4(44), pp. 23068-23077. (doi: 10.1039/C4RA01914H)

Abstract

The reaction of Co(OAc)2·4H2O with LH (LH = 11H-indeno[1,2-b]quinoxalin-11-one oxime) in MeOH in the presence of NEt3 forms the complex [CoIII2CoIIO(OAc)3L3]·0.5MeOH·0.2H2O (1·0.5MeOH·0.2H2O), while repeating the reaction under solvothermal conditions yielded the heptanuclear cluster [CoII7L9 (OH)2(OAc)2.7(MeO)0.3(H2O)]·4.6MeOH·3.3H2O (2·4.6MeOH·3.3H2O). Changing the starting metal salt to Co(ClO4)2·6H2O and upon the reaction with LH in the presence of NEt3 under high temperature and pressure, we managed to isolate the decanuclear cluster [CoII10L14(OH)3.6(MeO)0.4](ClO4)2·8.5MeOH·5.75H2O (3·8.5MeOH·5.75H2O), while under normal bench conditions and upon employment of pivalates in the reaction mixture complex [CoII4L4(piv)4(MeOH)2]·MeOH·H2O (4·MeOH·H2O) was formed. Furthermore, the reaction of Co(ClO4)2·6H2O with LH and aibH (2-amino-isobutyric acid) in the presence of NEt3 in MeOH gave the mononuclear complex [CoIIIL(aib)2]·3H2O (5·3H2O), while upon increasing the metal–ligand ratio cluster [CoIII2CoIIL4(aib)2(OH)2]·7.9MeOH (6·7.9MeOH) was isolated. Finally, repeating the reaction that yielded the mononuclear complex 5·3H2O under solvothermal conditions, gave the octanuclear cluster [CoII8L10(aib)2(MeO)2](ClO4)2·6.8MeOH·7H2O (7·6.8MeOH·7H2O). Variable temperature dc magnetic susceptibility studies for complexes 2, 3, 4 and 7, reveal that all clusters display dominant antiferromagnetic interactions leading to small or diamagnetic ground-states, S

• Item Type: Articles
• Additional Information: CJM would like to thank The Excellence Grant (ARISTEIA-2691) for funding. DIT would like to thank the 89439/2012 Grant of the Aristotle University of Thessaloniki.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Tsanai, Dr Angelos
• Authors: Canaj, A. B., Nodaraki, L. E., Ślepokura, K., Siczek, M., Tzimopoulos, D. I., Lis, T., and Milios, C. J.
• College/School: College of Science and Engineering > School of Chemistry
• Journal Name: RSC Advances
• Publisher: Royal Society of Chemistry
• ISSN: 2046-2069
• ISSN (Online): 2046-2069
• Copyright Holders: Copyright © 2014 The Royal Society of Chemistry
• First Published: First published in RSC Advances
• Publisher Policy: Reproduced under a Creative Commons License