Structures and Magnetic Properties of Carbonato-Bridged Hexanuclear NiII4LnIII2 (Ln = Gd, Tb, Dy) Complexes Formed by Atmospheric Carbon Dioxide Fixation in the Absence of an External Base

• DOI: 10.1021/acs.cgd.2c00298
• Publication Date: 2022-06-02T15:31:11Z
• Authors: Souvik Maity; Tanmoy Kumar Ghosh; Saki Ito; Pradip Bhunia; Takayuki Ishida; Ashutosh Ghosh
• Keywords: Octahedral molecular geometry; Base (topology)

The reaction of the mononuclear Ni(II) building block [NiL] an asymmetrically dicondensed N2O3 donor Schiff base ligand, N-salicylidene-N′-3-methoxysalicylidene-1,3-propanediamine (H2L), with LnCl3·6H2O (Ln = Gd, Tb, Dy) in a 2:1 molar ratio leads to formation three hexanuclear carbonato-bridged Ni4Ln2 complexes formulated as [Ni4Ln2(CO3)2Cl2(L)2(L′)2(CH3CN)2]·4CH3CN·2H2O Tb (2), Dy (3)), where H2L′ N,N′-bis(salicylidene)-1,3-propanediamine. In complex 1, unsymmetrical nature remains intact; however, 2 and 3, between two metalloligands coordinated each Ln, one is precursor ligand whereas other [NiL′] symmetrical formed by situ aldehyde-exchange during Ln salts. Ln(III) centers are octacoordinated biaugmented-trigonal-prismatic geometry all complexes. half possess distorted octahedral while has square-pyramidal geometry; 3 have distorted-octahedral geometry. A magnetic study clarifies that Ni–Ln exchange couplings ferromagnetic. Though consist [Ln2Ni4] system, properties been analyzed on trinuclear Ni–Ln–Ni basis. parameter 2JGd–Ni/kB 1 was estimated be +0.61 +0.84 K across double-oxide bridges. Complexes exhibited indication single-molecule magnets ac susceptibility study.