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Inorg Chem ; 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32538622


A series of four isomorphous, 1:2 (complex/L) rare cocrystals of coordination compounds of Ln(III) ions as [Ln(L)(NO3)3(H2O)]2[L]2 (Ln(III) = Gd (1), Tb (2), Dy (3), and Ho (4)), were synthesized with N,N-diisobutylisonicotinamide (L) using a metal-to-ligand ratio of 1:1. All compounds are dimeric in nature with two cocrystallized L molecules centro-symmetrically interspersed between two dimeric units with H-bonded bridges between them to form interesting, self-assembled H-bonded tapes along the c-axis. Detailed Shape analysis and Hirshfeld analysis are done to demonstrate geometry around the metal centers and various noncovalent interactions present in the systems, respectively. Magnetic studies show that compound 3 is a field-induced single-molecule magnet (SMM) for which the magnetization relaxes through a combination of Orbach (Δ = 51 K and τ0 = 3.1 × 10-7 s) and Raman mechanisms. Solid-state luminescence studies reveal that compounds 1, 2, and 3 are photoluminescent in the visible range, while 4 exhibits luminescence in the NIR region. Compound 3 shows cold white-light emission with Commission Internationale de l'Eclairage (CIE) coordinates (0.31, 0.30) and correlated color temperature (CCT) value of 6942 K.

ACS Omega ; 4(20): 18520-18529, 2019 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-31737810


A hydrazone-based N'1,N'3-bis((E)-4-(diethylamino)-2 -hydroxybenzylidene)isophthalohydrazide (NDHIPH), has been synthesized, characterized, and assessed for its highly selective and sensitive (limit of detection, 2.53 nM) response toward Al(III) via fluorescence enhancement in 95% aqueous medium. All experimental results of analytical studies are in good consonance with the theoretical studies performed. Further, this NDHIPH-Al(III) ensemble is used for selective and sensitive (12.15 nM) detection of explosive picric acid (PA) via fluorescence quenching. This reversible behavior of NDHIPH toward Al(III) and PA is used for the creation of a molecular logic gate.

Dalton Trans ; 48(12): 3922-3929, 2019 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-30816374


A centro-symmetric binuclear compound of formula [Dy(L)·(CH3COO)2·(H2O)2]2 (1) was isolated from the reaction between the 2,4-dinitrobenzoate anion (L) and the tris(acetate) of Dy(iii). Single crystal diffraction studies reveal a µ1-κ2,η1:η1 chelating binding mode of L while the binuclear compound is formed by the two bridging (µ2-κ3,η1:η2) acetate anions. The nona-coordinated sphere of each Dy(iii) ion is filled with a chelating (κ2,η1:η1) acetate anion and two terminal water molecules. Static magnetic measurements combined with ab initio SA-CASSCF/RASSI-SO calculations lead to two intramolecular competitive interactions i.e. ferromagnetic exchange interactions (0.04 cm-1) and antiferromagnetic dipolar interactions (-0.5 cm-1). Finally, dynamic magnetic measurements revealed a Single-Molecule Magnet behaviour in a zero-applied magnetic field with an effective energy barrier Δ = 21.5(2) cm-1 and τ0 = 7(3) × 10-6 s through Orbach and Quantum Tunnelling of the Magnetization relaxation mechanisms.

Dalton Trans ; 47(13): 4722-4732, 2018 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-29537422


Single crystal diffraction studies reveal the formation of the following 10 new complexes of lighter Ln(iii) ions with general formulas {[Ln(µ2-L1)3·(H2O)2]·H2O}n (Ln = Nd (1) and Eu (2)), [Nd(µ2-L2)2·(CH3COO)·(H2O)2]n (3), [Ln2(µ2-L2)5·(L2)·(H2O)4]n (Ln = Sm (4), Ce (5), and Pr (6)), [La2(µ2-L2)6·(H2O)3·(DMF)]n (7) (DMF = dimethylformamide), [Ln(µ2-L2)2·(L2)·(H2O)3]2 (Ln = Eu (8) and Gd (9)) and [Gd(L2)·(CH3COO)2·(H2O)2]2 (10), where L1 and L2 are anions of 3,5- and 2,4-dinitrobenzoic acid, respectively. Complexes 1-7 are 1D coordination polymers, while 8-10 are dinuclear complexes. The luminescence properties of Nd(iii) and Eu(iii) analogues displayed metal-centred emission with L1 exhibiting weak but more efficient sensitization than L2. A study of the magnetic properties of the compounds clearly demonstrated the field-induced single ion magnet behaviour of the Nd(iii) compounds 1 and 3. Their behaviour has been compared to previously reported analogous Nd(iii) complexes and the role of the lattice solvent and polymorphism on the magnetic behaviour has been evaluated.