From tetranuclear to pentanuclear [Co‒Ln] (Ln = Gd, Tb, Dy, Ho) complexes across the lanthanide series: effect of varying sequence of ligand addition

Basak, D., Smythe, L., Herchel, R., Murrie, M. , Nemec, I. and Ray, D. (2021) From tetranuclear to pentanuclear [Co‒Ln] (Ln = Gd, Tb, Dy, Ho) complexes across the lanthanide series: effect of varying sequence of ligand addition. Dalton Transactions, 50(34), pp. 11861-11877. (doi: 10.1039/D1DT02038B) (PMID:34369499)

Abstract

Two new families of cobalt(II/III)‒lanthanide(III) coordination aggregates have been reported: Tetranuclear [LnIII2CoIII2L2(N‒BuDEA)2(O2CCMe3)4(H2O)2]•(MeOH)n•(H2O)m (Ln = Gd, 1; Tb, 2; Dy, 3; n=2, m=10 for 1 and 2; n=6, m=2 for 3) and Pentanuclear LnIII2CoIICoIII2L2(N‒BuDEA)2(O2CCMe3)6(MeOH)2 (Ln = Dy, 4; Ho, 5) formed from the reaction of two aggregation assisting ligands H2L (o‒vanillin oxime) and N‒BuDEAH2 (N‒butyldiethanolamine). A change in preference from lower to higher nuclearity structure was observed on going across the lanthanide series brought about by the variation in size of the LnIII ions. An interesting observation was made for the varying sequence of addition of the ligands in the reaction medium paving the way to access both structural types for Ln = Dy. HRMS (+ve) of solutions gave further insight into the formation of the aggregates via different pathways. The tetranuclear complexes adopt a modified butterfly structure with a more complex bridging network while trapping of an extra CoII ion in the pentanuclear complexes destroy this arrangement putting the Co‒Co‒Co axis above the Ln‒Ln axis. Direct current (dc) magnetic susceptibility measurements reveal weak antiferromagnetic coupling in 1. Complexes 2 and 5 display no slow magnetic relaxation, whereas complexes 3 and 4 display out‒of‒phase signals at low temperature. All compounds were analyzed with DFT and CASSCF calculations and information about the single-ion anisotropies and mutual 4f‒4f / 4f‒3d magnetic interactions were derived.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Smythe, Ms Lucy and Murrie, Professor Mark
• Authors: Basak, D., Smythe, L., Herchel, R., Murrie, M., Nemec, I., and Ray, D.
• College/School: College of Science and Engineering > School of Chemistry
• Journal Name: Dalton Transactions
• Publisher: Royal Society of Chemistry
• ISSN: 1477-9226
• ISSN (Online): 1477-9234
• Published Online: 21 July 2021
• Copyright Holders: Copyright © 2021 The Royal Society of Chemistry
• First Published: First published in Dalton Transactions 50(34): 11861-11877
• Publisher Policy: Reproduced in accordance with the publisher copyright policy