Supertetrahedral T2 clusters in 3d-4f {Fe4Ln6}: Synthesis, crystal structure, magnetic and photoluminescent properties

Two new isomorphous Iron(III)-lanthanide(III) coordination clusters of general formula [Fe(4)Ln(6)(bpte)(4)(mu(4)-O)(4)(EG)(4)(mu(3)-OMe) 3.3(mu(3)-Cl)(0.70)Cl-2(MeOH)(2)][Fe(4)Ln(6)(bpte)(4)(mu(4)-O)(4)(EG)(4)(mu(3)-OMe)(4)Cl-2(MeOH)(2)]center dot 30H(2)O center dot MeOH (H(2)bpte = 1,2-bis(3-(pyridin-2-yl)-1H-1,2,4-triazol-5-yl) ethane, EG = ethylene glycol, Ln = Dy(1), Ho(2)) have been successfully synthesized under hydrothermal conditions. The crystal structure of 2 consists of two asymmetric units having two isostructural cores{Fe4Ho6(mu(4)-O)(4)} of T2 supertetrahedral cluster nuclei ultra-structural unit. Both complexes 1 and 2 are found to be isomorphous which is confirmed by FTIR, elemental analysis, PXRD, and thermal studies. These are the first supertetrahedral T2 coordination clusters reported as 3d-4f system. The magnetic measurements indicate that antiferromagnetic coupling in both of these complexes. The solid-state photoluminescent measurements for 1 and 2 were done but only 1 gave rise to a measurable emission peaks which are associated with the 4f -> 4f transitions with a maximum at 574 nm (cyan emission).