A Chiral Bipyrimidine-Bridged Dy2 SMM: A Comparative Experimental and Theoretical Study of the Correlation Between the Distortion of the DyO6N2 Coordination Sphere and the Anisotropy Barrier Diaz Ortega, Ismael Herrera Martínez, Juan Manuel Reyes Carmona, Álvaro Galán Mascarós, Jose Ramón Dey, Sourav Nojiri, Hiroyuki Rajaraman, Gopalan Colacio Rodríguez, Enrique Bipyrimidine-bridged Ab initio calculations Magnetic properties Diketonates Chiral bipyrimidine-bridged dinuclear LnIII complexes of general formula [(μ-bipym){((+)-tfacam)3Ln}2] and [(μ-bipym){((-)-tfacam)3Ln}2], have been prepared from the assembly of Ln(AcO)3·nH2O (LnIII = Dy, Gd), (+)/(−)-3-(trifluoroacetyl)camphor enantiopure ligands ((+)/(-)-Htfacam) and bipyrimidine (bipym). The structure and chirality of these complexes have been supported by single-crystal X-Ray diffraction and circular dichroism. The study of the magnetic properties of the GdIII complexes revealed a very weak antiferromagnetic interaction between the GdIII ions through the bipyrimidine bridging ligand. Ab initio CASSCF calculations indicated that the ground Kramers doublet (KD) of both DyIII centers is almost purely axial with the anisotropy axis located close to the two tfacam−ligands at opposite sides of each DyIIIatom, which create an axial crystal field. In keeping with this, ac dynamic measurements indicated slow relaxation of the magnetization at zero field with Ueff = 55.1 K, a pre-exponential factor of τo = 2.17·10−6 s and τQTM = 8 μs. When an optimal dc field of 0.1 T is applied, QTM is quenched and Ueff increases to 75.9 K with τo = 6.16 × 10−7 s. The DyN2O8 coordination spheres and SMM properties of [(μ-bipym){((+)-tfacam)3Ln}2] and their achiral [(Dy(b-diketonate)3)2(μ-bpym)]analogous have been compared and a magneto-structural correlation has been established, which has been supported by theoretical calculations. 2019-10-30T11:48:41Z 2019-10-30T11:48:41Z 2018-11-08 info:eu-repo/semantics/article Díaz-Ortega IF, Herrera JM, Reyes Carmona Á, Galán-Mascarós JR, Dey S, Nojiri H, Rajaraman G and Colacio E (2018) A Chiral Bipyrimidine-Bridged Dy2 SMM: A Comparative Experimental and Theoretical Study of the Correlation Between the Distortion of the DyO6N2 Coordination Sphere and the Anisotropy Barrier. Front. Chem. 6:537. http://hdl.handle.net/10481/57618 10.3389/fchem.2018.00537 eng http://creativecommons.org/licenses/by/3.0/es/ info:eu-repo/semantics/openAccess Atribución 3.0 España Frontiers Media