Partial hydrogen bonds: structural studies on thioureidoalkylphosphonates.

Area of Science:

• Organophosphorus Chemistry
• Crystallography
• Computational Chemistry

Background:

• Organophosphorus compounds are vital in various chemical applications.
• Understanding molecular structure and bonding is crucial for predicting chemical behavior.
• Hydrogen bonding significantly influences molecular interactions and material properties.

Purpose of the Study:

• To elucidate the X-ray crystal and molecular structures of three novel diphenyl phosphonate derivatives.
• To investigate the nature of intermolecular interactions, particularly hydrogen bonds, using computational methods.
• To analyze the electron density distribution and characteristics of bond critical points in these compounds.

Main Methods:

• X-ray crystallography was employed to determine the solid-state structures of the target compounds.
• Density Functional Theory (DFT) calculations (B3LYP/6-311+G(d)) were performed on dimer models.
• Theoretical electron densities were studied, focusing on bond critical points and their properties (electron density, Laplacian).

Main Results:

• The crystal structures of diphenyl 1-(3-phenylthioureido)propylphosphonate, diphenyl 1-(3-phenylthioureido)methylthio-propylphosphonate, and diphenyl [2-methyl-1-(3-methylthioureido)propyl]phosphonate were determined.
• DFT calculations provided insights into the electronic structure and hydrogen bonding characteristics.
• Analysis of bond critical points characterized the bifurcated acceptor hydrogen bonds present in the dimers.

Conclusions:

• The study provides a detailed structural and electronic characterization of novel phosphonate compounds.
• The findings highlight the importance of hydrogen bonding in the molecular assembly of these organophosphorus compounds.
• This research contributes to the understanding of structure-property relationships in thioureido-substituted phosphonates.