Dr. Sujesh Baby

EDUCATION

MSc, PhD

RESEARCH, TEACHING, or OTHER INTERESTS

Chemistry, Inorganic Chemistry, Materials Science, Materials Chemistry

Scopus Publications

Synthesis, crystal structure and antifungal activity of an ethylenediammonium-templated nickel(II) pyromellitate coordination polymer
Sujesh Baby, Alex P. Andrews, M. Padmanabhan
Acta Crystallographica Section C Structural Chemistry, 2026
Coordination polymers represent an important class of inorganic–organic hybrid materials constructed from metal nodes interconnected by multidentate organic ligands. Here, a one-dimensional anionic coordination polymer, namely, catena -poly[ethylenediammonium [tetraaquanickel(II)]-μ-benzene-1,2,4,5-tetracarboxylato] dihydrate], {(C 2 H 10 N 2 )[Ni(C 10 H 2 O 8 )(H 2 O) 4 ]·2H 2 O} n , (1), constructed from Ni II ions and pyromellitate (benzene-1,2,4,5-tetracarboxylate, btec 4− ) ligands has been successfully synthesized through an amine-templating strategy; notably, the polymeric framework does not form in the absence of the amine template, underscoring the decisive structure-directing role of the amine. The obtained polymeric system was characterized by spectral, elemental, thermal and single-crystal X-ray diffraction techniques. Single-crystal X-ray diffraction shows that the centrosymmetric btec 4− ligand bridges two Ni II centres in a trans -monodentate coordination mode through two deprotonated carboxylate groups, forming an extended one-dimensional anionic chain. The remaining two trans -disposed carboxylate groups of btec 4− remain uncoordinated. Each Ni II centre adopts a distorted octahedral coordination geometry, with two sites occupied by carboxylate O atoms of bridging btec 4− ligands, coordinated in a monodentate fashion, and the remaining four sites occupied by coordinated water molecules. Protonated ethylenediammonium cations are aligned parallel to the polymeric chains and act as counter-ions to maintain charge balance. Extensive O—H...O and N—H...O hydrogen-bonding interactions link the chains into a multidimensional supramolecular architecture. Compound (1) exhibits appreciable water solubility and solvent processability. Preliminary antifungal studies indicate significant inhibitory activity against Candida albicans .
Open-aperture Z-scan and optical limiting of plasmonic silver-polymer system
Journal of Optoelectronics and Advanced Materials, 2022
Quasi-two-dimensional magnetism in spin-1/2 square lattice compound Cu[C6H2(COO)4][H3N-(CH2)2-NH3] • 3H2O
S. Guchhait, S. Baby, M. Padmanabhan, A. Medhi, R. Nath
Epl, 2021
We report the crystal growth and structural and magnetic properties of quasi-two-dimensional quantum magnet Cu[C6H2(COO)4][H3N-(CH2)2-NH3] 3H2O. It is found to crystallize in a monoclinic structure with space group . The CuO4 plaquettes are connected into a two-dimensional framework in the ab-plane through the anions of [C6H2(COO)4]4− (pyromellitic acid). The [H3N-(CH2)2-NH3] 3H2O groups are located between the layers and provide a weak interlayer connection via hydrogen (H...O) bonds. The temperature-dependent magnetic susceptibility is well described by frustrated square lattice model with nearest-neighbor interaction and next-nearest-neighbor interaction . Our analysis using frustrated rectangular lattice model also confirms almost isotropic nearest-neighbour interactions ( and ) in the ab-plane and . Further, the isothermal magnetization at is also well described by a non-frustrated square lattice model with . Based on the ratio, the compound can be placed in the Néel antiferromagnetic state of the phase diagram. No signature of magnetic long-range order is detected down to 2 K.
Quasi-two-dimensional S = 1/2 magnetism of Cu[C6H2(COO)4][C2H5 NH3]2
R. Nath, M. Padmanabhan, S. Baby, A. Thirumurugan, D. Ehlers, M. Hemmida, H.-A. Krug von Nidda, A. A. Tsirlin
Physical Review B Condensed Matter and Materials Physics, 2015
We report structural and magnetic properties of the spin-$\frac{1}{2}$ quantum antiferromagnet $\mathrm{Cu[}{\mathrm{C}}_{6}{\mathrm{H}}_{2}{(\mathrm{COO})}_{4}\mathrm{][}{\mathrm{C}}_{2}{\mathrm{H}}_{5}{\mathrm{NH}}_{3}\mathrm{]}{}_{2}$ by means of single-crystal x-ray diffraction, magnetization, heat capacity, and electron-spin-resonance (ESR) measurements on polycrystalline samples, as well as band-structure calculations. The triclinic crystal structure of this compound features ${\mathrm{CuO}}_{4}$ plaquette units connected into a two-dimensional framework through anions of the pyromellitic acid $\mathrm{[}{\mathrm{C}}_{6}{\mathrm{H}}_{2}{(\mathrm{COO})}_{4}{\mathrm{]}}^{4\ensuremath{-}}$. The ethylamine cations $\mathrm{[}{\mathrm{C}}_{2}{\mathrm{H}}_{5}{\mathrm{NH}}_{3}{]}^{+}$ are located between the layers and act as spacers. Magnetic susceptibility and heat capacity measurements establish a quasi-two-dimensional, weakly anisotropic, and nonfrustrated spin-$\frac{1}{2}$ square lattice with the ratio of the couplings ${J}_{a}/{J}_{c}\ensuremath{\simeq}0.7$ along the $a$ and $c$ directions, respectively. No clear signatures of the long-range magnetic order are seen in thermodynamic measurements down to 1.8 K. However, the gradual broadening of the ESR line suggests that magnetic ordering occurs at lower temperatures. Leading magnetic couplings are mediated by the organic anion of the pyromellitic acid and exhibit a nontrivial dependence on the Cu-Cu distance, with the stronger coupling between those Cu atoms that are farther apart.

RECENT SCHOLAR PUBLICATIONS

Synthesis, crystal structure and antifungal activity of an ethylenediammonium-templated nickel (II) pyromellitate coordination polymer
S Baby, AP Andrews, M Padmanabhan
Crystal Structure Communications 82 (5) , 2026
2026.0
Quasi-two-dimensional magnetism in spin-square lattice compound Cu [C6H2 (COO) 4][H3N-(CH2) 2-NH3]· 3H2O
S Guchhait, S Baby, M Padmanabhan, A Medhi, R Nath
Europhysics Letters 133 (5), 57006 , 2021
2021.0
Citations: 6
Quasi-two-dimensional magnetism of
R Nath, M Padmanabhan, S Baby, A Thirumurugan, D Ehlers, ...
Physical Review B 91 (5), 054409 , 2015
2015.0
Citations: 35
Open-aperture Z-scan and optical limiting of plasmonic silver-polymer system
AM JANCY JOHN1, VINOY THOMAS1,*, SUJESH BABY2, RAMAKRISHNAN JAYAKRISHNAN3 ...
JOURNAL OF OPTOELECTRONICS AND ADVANCED MATERIALS 24, 250-255 , 0
Citations: 3
Cu [C6H2 (COO) 4][H3N-(CH2) 2-NH3]· 3H2O
S Guchhait, S Baby, M Padmanabhan, A Medhi, R Nath

MOST CITED SCHOLAR PUBLICATIONS

Quasi-two-dimensional magnetism of
R Nath, M Padmanabhan, S Baby, A Thirumurugan, D Ehlers, ...
Physical Review B 91 (5), 054409 , 2015
2015.0
Citations: 35
Quasi-two-dimensional magnetism in spin-square lattice compound Cu [C6H2 (COO) 4][H3N-(CH2) 2-NH3]· 3H2O
S Guchhait, S Baby, M Padmanabhan, A Medhi, R Nath
Europhysics Letters 133 (5), 57006 , 2021
2021.0
Citations: 6
Open-aperture Z-scan and optical limiting of plasmonic silver-polymer system
AM JANCY JOHN1, VINOY THOMAS1,*, SUJESH BABY2, RAMAKRISHNAN JAYAKRISHNAN3 ...
JOURNAL OF OPTOELECTRONICS AND ADVANCED MATERIALS 24, 250-255 , 0
Citations: 3
Synthesis, crystal structure and antifungal activity of an ethylenediammonium-templated nickel (II) pyromellitate coordination polymer
S Baby, AP Andrews, M Padmanabhan
Crystal Structure Communications 82 (5) , 2026
2026.0
Cu [C6H2 (COO) 4][H3N-(CH2) 2-NH3]· 3H2O
S Guchhait, S Baby, M Padmanabhan, A Medhi, R Nath