Heterometallic Hexanuclear [Cu Ln ] Complexes Showing Zero-field SMM Behaviour and Magnetocaloric Effect.

Three heterometallic hexanuclear 3d-4f complexes bearing the formula [Cu (L) Ln (L) (o-van) ] [L=2-((E)-((2-hydroxyphenyl)imino]methyl)phenol; o-van=ortho-vanillin] (Ln =Gd (1), Dy (2), and Tb (3)) have been synthesized and characterized. DC magnetic susceptibility measurements reveal overall antiferromagnetic interactions in 1 and 3, whereas co-existence of ferro- as well as antiferromagnetic interactions were observed in 2. The magnetocaloric effect has been observed for 1 with an entropy change (-ΔS ) of 22.

Lanthanide-Based Layer-Type Two-Dimensional Coordination Polymers Featuring Slow Magnetic Relaxation, Magnetocaloric Effect and Proton Conductivity.

Three lanthanide-based two-dimensional (2D) coordination polymers (CPs), [Ln(L)(H O) ] , {H L=(HO) P(O)CH CO H; Ln=Dy (CP 1), Er (CP 2)} and [{Gd (L) (H O) } H O] , (CP 3) were hydrothermally synthesized using phosphonoacetic acid as a linker. Structural features revealed that the dinuclear Ln nodes were present in the 2D sheet of CP 1 and CP 2 while in the case of CP 3, nodes were further connected to each other forming a chain-type arrangement throughout the network. The magnetic studies show field-induced slow magnetic relaxation property in CP 1 and CP 2 with U values of 72 K (relaxation time, τ =3.

Above Room Temperature Spin Transition in Thermally Stable Mononuclear Fe(III) Complexes.

Two solvent-free mononuclear Fe(III) complexes [Fe(L)]NO (1) and [Fe(L)]ClO (2) have been synthesized by employing a new π-conjugated azo-phenyl substituted ligand, 2-(( E)-((2-(ethylamino)ethyl)imino)methyl)-4-(2-phenyldiazenyl)phenol (HL). The noncoordinated azo-phenyl part of the ligand adopts two different conformations which can exert a varied local distortion around the metal center affecting the spin crossover behavior. The magnetic data (2-450 K) reveal that complex 1 displays spin crossover above room temperature where the ligand is in linear form, while complex 2 shows an incomplete spin transition where the ligand adopts a skew form in the solid state.

3D isomorphous lanthanide coordination polymers displaying magnetic refrigeration, slow magnetic relaxation and tunable proton conduction.

Four new isostructural lanthanide-based three-dimensional (3D) coordination polymers (CPs), {[Ln(OH)(L)(HO)]·4.6HO·1.4CHCN} (Ln = Gd (1), Dy (2), Ho (3) and Er (4)), have been constructed using a sulfonate-carboxylate-based ligand (NaHL = disodium-2,2'-disulfonate-4,4'-oxydibenzoic acid) and the corresponding lanthanide metal(iii) nitrates.

Channel-Assisted Proton Conduction Behavior in Hydroxyl-Rich Lanthanide-Based Magnetic Metal-Organic Frameworks.

Two new lanthanide-based 3D metal-organic frameworks (MOFs), {[Ln(L)(Ox)(HO)]·xHO} [Ln = Gd and x = 3 (1) and Dy and x = 1.5 (2); HL = mucic acid; OxH = oxalic acid] showing interesting magnetic properties and channel-mediated proton conduction behavior, are presented here. Single-crystal X-ray structure analysis shows that, in complex 1, the overall structure originates from the mucate-bridged gadolinium-based rectangular metallocycles.