Novel mixed-valent CoII2CoIII4LnIII4aggregates with ligands derived from tris-(hydroxymethyl)aminomethane (Tris)This paper is dedicated to the memory of Dr Ian J. Hewitt.Electronic supplementary information (ESI) available: Experimental details, selected bond lengths and angles, binding modes of (Htris)2−ligand, additional magnetic data. CCDC reference numbers 758590–758592. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c000008f

Isostructural CoII2CoIII4LnIII4(Ln = Y (1), Gd (2) and Dy (3)) coordination clusters formed using the ligand Tris are the first examples of 3d-4f complexes involving this ligand and show weak ferromagnetic coupling between the CoIIions and slow relaxation (SMM) behaviour for 3. [ABSTRACT FROM AUTHOR]