Ab initio HF/6-31+G*, MP2/6-31+G*, B3LYP/6-31+G* level calculations have been performed on HSe-NH₂ to estimate the Se-N rotational barriers and N-inversion barriers. Two conformers have been found withsyn andanti arrangement of the NH₂ hydrogens with respect to Se-H bond. The N inversion barriers in selenamide are 1.65, 2.47, 1.93 kcal/mol and the Se-N rotational barriers are 6.58, 6.56 and 6.12 kcal/mol respectively at HF/6-31+G*, MP2/6-31+G* and B3LYP/6-31+G* levels respectively. The n_N →Σ *_Se-H negative hyperconjugation is found to be responsible for the higher rotational barriers.

Coordination chemistry of bonds between main group elements and electron donating ligands as in L→E (where E is electron acceptor centre like C⁰, Si⁰, N¹, P¹, As¹, B¹ and L is an electron donating N-heterocyclic carbene) have been recently gaining attention. Many important drugs have nitrogen atom as an electron acceptor center and can be represented by two general formulae:(L→N←L)^⊕ and L→N-R. Divalent N¹ compounds possess two lone pairs at central nitrogen and low nucleophilicity associated with them are found to be of importance. In this article, electronic structure analysis of drug molecules like picloxydine, chlorhexidine, and moroxydine were performed at B3LYP/6-311++G(d,p) level of theory. Evaluation of electron localization function (ELF), molecular orbitals, charge density, nucleophilicity, proton affinity and complexation energy estimation confirm the presence of coordination bonds (L→N←L)^⊕ in the above mentioned drug molecules in their cationic state. Further, electronic structure analysis of drugs like clonidine, apraclonidine, brimonidine and xylazine indicated the presence of electronic structure similar to L→N-R systems.

Molecular Property Diagnostic Suite (MPDS^TB) is a web tool (http://mpds.osdd.net) designed to assist the in silico drug discovery attempts towards Mycobacterium tuberculosis (Mtb). (MPDS^TB) tool has nine modules which are classified into data library (1–3), data processing (4–5) and data analysis (6–9). Module 1 is a repository of literature and related information available on the Mtb. Module 2 deals with the protein targetanalysis of the chosen disease area. Module 3 is the compound library consisting of 110.31 million unique molecules generated from public domain databases and custom designed search tools. Module 4 contains toolsfor chemical file format conversions and 2D to 3D coordinate conversions. Module 5 helps in calculating the molecular descriptors. Module 6 specifically handles QSAR model development tools using descriptors generated in the Module 5. Module 7 integrates the AutoDock Vina algorithm for docking, while module 8 provides screening filters. Module 9 provides the necessary visualization tools for both small and large molecules. The workflow-based open source web portal,(MPDS^TB) 1.0.1 can be a potential enabler for scientists engaged in drug discovery in general and in anti-TB research in particular.