Organic–inorganic composite materials, combining
polymers
with transition metal (TM) atoms based on PAni and 3d TMs, have been
designed and investigated in various spin states by performing density
functional calculations. These designed composites were analyzed for
their stability in different spin states as well as for their calculated
electronic properties, including binding energies, frontier molecular
orbitals, and dipole moments. Additionally, 3D isosurfaces and 2D
scattered plots of reduced density gradient as a function of (sign
λ2)ρ provide insights into the noncovalent
interactions between the composite units. The most stable Mn@PAni
composite has been assessed as a sensing material for chemical warfare
blood agents (HCN, NCCl, NCBr, NCCN, and AsH3) using density
functional-based calculations. The reduced band gap and significant
red/blue shift in the UV–vis spectra obtained through TDDFT
calculations underline the selectivity and efficiency of the Mn@PAni
composite toward different analytes.