  The work presents the electronic structure, spin state and optical properties
of TM-dinuclear molecules (TM = Cr, Mn, Fe, Co, and Ni) which was modelled
according to the recently reported Pt$^{II}$-dinuclear complex
data\cite{kar_colour_2016}. The molecules were geometrically optimized in the
gas phase and their stability were analyzed from vibrational spectra study
using density functional theory (DFT) calculations. The ground spin state of
the tetra-coordinated TM atom in the modeled molecules was predicted based on
the relative energies between the possible spin states of the molecules. We
further performed DFT+U calculations to investigate the precise ground state
spin configuration of molecules. Interestingly, optical characterization of
these molecules shows that the absorption spectra have a large peak in the
blue-light wavelength range, therefore could be suitable for blue-LED
application. Our work promotes further computational and experimental studies
on TM-dinuclear molecules in field of molecular spintronics and
optoelectronics.
