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Lanthanide‐Based Layer‐Type Two‐Dimensional Coordination Polymers Featuring Slow Magnetic Relaxation, Magnetocaloric Effect and Proton Conductivity
Author(s) -
Bera Siba Prasad,
Mondal Arpan,
Konar Sanjit
Publication year - 2019
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.201900842
Subject(s) - magnetic refrigeration , lanthanide , magnetic relaxation , proton , relaxation (psychology) , crystallography , chemistry , ion , conductivity , ab initio , ab initio quantum chemistry methods , materials science , magnetic field , molecule , physics , magnetization , social psychology , psychology , organic chemistry , quantum mechanics
Three lanthanide‐based two‐dimensional (2D) coordination polymers (CPs), [Ln(L)(H 2 O) 2 ] n , {H 3 L=(HO) 2 P(O)CH 2 CO 2 H; Ln=Dy 3+ (CP 1 ), Er 3+ (CP 2 )} and [{Gd 2 (L) 2 (H 2 O) 3 } . H 2 O] n , (CP 3 ) were hydrothermally synthesized using phosphonoacetic acid as a linker. Structural features revealed that the dinuclear Ln 3+ 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 eff values of 72 K (relaxation time, τ 0 =3.05×10 −7 s) and 38.42 K (relaxation time, τ 0 =4.60×10 −8 s) respectively. Ab‐initio calculations suggest that the g tensor of Kramers doublet of the lanthanide ion (Dy 3+ and Er 3+ ) is strongly axial in nature which reflects in the slow magnetic relaxation behavior of both CPs. CP 3 exhibits a significant magnetocaloric effect with −Δ S m =49.29 J kg −1 K −1 , one of the highest value among the reported 2D CPs. Moreover, impedance analysis of all the CPs show high proton conductivity with values of 1.13×10 −6 S cm −1 , 2.73×10 −3 S cm −1 and 2, 6.27×10 −6 S cm −1 for CPs 1 – 3 , respectively, at high temperature (>75 °C) and maximum 95 % relative humidity (RH).