2015 Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Mechanism / Preclinical Unspecified
2015 · Bharty et al. — Synthesis, spectral characterization, thermal behaviour, antibacterial activity and DFT calculation on N'-[bis(methylsulfanyl)methylene]-2-hydroxybenzohydrazide and N'-(4-methoxybenzoyl)-hydrazinecarbodithioic acid ethyl ester.
Super-Abstract
Two new synthetic compounds based on hydrazone scaffolds were characterised by X-ray crystallography, NMR, IR, and thermal analysis; both showed antibacterial activity and nonlinear optical (NLO) properties superior to urea. Density functional theory (DFT) calculations confirmed the molecular geometry and electronic properties. This is a pure synthetic chemistry / in-vitro study with no connection to molecular hydrogen (H₂) biology.
Commentary
This paper describes the synthesis and full characterisation of two novel hydrazone-based compounds: Hbmshb (1) and H2mbhce (2). Single-crystal X-ray diffraction established their crystal structures (orthorhombic and monoclinic systems, respectively), while DFT/B3LYP calculations provided geometry optimisation, frontier molecular orbital (FMO) analysis, and non-linear optical (NLO) property assessment. Compound 2 is additionally stabilised by CH⋯π and NH⋯π interactions. Both compounds showed NLO activity exceeding that of urea (a standard reference material) and demonstrated antimicrobial activity against bacterial strains tested. The study is a standard synthetic chemistry contribution to medicinal/materials chemistry. It has no relevance to molecular hydrogen (H₂) therapy; „hydrogen“ appears only in the context of conventional hydrogen bonding and NH groups — universal chemical features with no relationship to dissolved H₂ gas.
Key quotes
- „Inter and intra molecular hydrogen bonding link two molecules and provide linear chain structure.“ — structural result: conventional hydrogen bonding governs crystal packing — unrelated to H₂ gas
- „Compounds 1 and 2 are thermally stable and show NLO behaviour better than the urea crystal.“ — materials science result: both compounds outperform urea as nonlinear optical materials
- „The bioefficacy of compounds has been examined against the growth of bacteria to evaluate their anti-microbial potential.“ — biological testing: antibacterial screening was performed
Our assessment
This is a synthetic chemistry and materials science study — it reports the characterisation of new compounds with potential in antimicrobial drug design and photonics/NLO applications. It has zero relevance to molecular hydrogen (H₂) medicine or therapy. Its inclusion in H₂ research databases is a false-positive from keyword matching on „hydrogen bonding.“ The antibacterial activity results are preliminary (in-vitro MIC-type screening only) and provide no clinical evidence.
Study design
- Type: synthetic chemistry + in-vitro study · Compounds: two novel hydrazone derivatives (Hbmshb, H2mbhce) · H₂ relevance: none (hydrogen bonds = standard chemistry)
- Characterisation methods: elemental analysis, IR, NMR, single-crystal X-ray diffraction, TGA, DFT/B3LYP · Biological tests: antibacterial activity against unspecified bacterial strains · Result: both compounds thermally stable, NLO activity > urea, antibacterial activity demonstrated
Abstract
Two new compounds N'-[bis(methylsulfanyl) methylene]-2-hydroxybenzohydrazide {Hbmshb (1)} and N'-(4-methoxy benzoyl)-hydrazinecarbodithioic acid ethyl ester {H2mbhce (2)} have been synthesized and characterized with the aid of elemental analyses, IR, NMR and single crystal X-ray diffraction data. Compounds 1 and 2 crystallize in orthorhombic and monoclinic systems with space group Pna21 and P21/n, respectively. Inter and intra molecular hydrogen bonding link two molecules and provide linear chain structure. In addition to this, compound 2 is stabilized by CH⋯π and NH⋯π interactions. Molecular geometry from X-ray analysis, geometry optimization, charge distribution, bond analysis, frontier molecular orbital (FMO) analysis and non-linear optical (NLO) effects have been performed using the density functional theory (DFT) with the B3LYP functional. The bioefficacy of compounds has been examined against the growth of bacteria to evaluate their anti-microbial potential. Compounds 1 and 2 are thermally stable and show NLO behaviour better than the urea crystal.
Source & links
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