N-Thiophosphorylthioureas RNHC(S)NHP(S)(OiPr)2 as an Excellent Platform for Studying the Synergy between Hydrogen-Hydrogen Bonding and Other Families of Non-Covalent Interactions

A family of thiourea based derivatives, RNHC(S)NHP(S)(OiPr)(2) [R = Ph (YEZNUN), 2-MeC6H4 (AQOYAH), 2,5-Me2C6H3 (WARREO), 2,6-Me2C6H3 (GUJGUO), 2,4,6-Me3C6H2 (AQOYEL), PhNH (QORXUR), 1-naphthyl (MOWPEU)], has been studied to understand the synergy between dihydrogen and other (non)conventional non-covalent interactions. It was established that all monomers are stabilized through intramolecular dihydrogen C-H H -C interactions. Additionally, C-H interactions are noted in AQOYAH , WARREO, and MOWPEU; N-H O interactions in AQOYAH , and WARREO; C-H S interactions in GUJGUO , YEZNUN, and AQOYEL; N-H S interactions in GUJGUO , AQOYEL, MOWPEU, and YEZNUN; and N-H N interactions in QORXUR . The crystal structures of all the thioureas are further stabilized by the most pronounced intermolecular C-H H -C interactions followed by N-H S and C -H S with the formation of centrosymmetric R-2( 2)(8) dimers. These non-covalent interactions are augmented by the stacking in YEZNUN and MOWPEU ; C-H in WARREO , GUJGUO, AQOYEL and MOWPEU; N-H in QORXUR . The synergy between intra- and intermolecular C-H H -C and other types of non-covalent interactions lead to the extraordinary stability of these systems as indicated by the ETS-NOCV Scheme Although the London dispersion forces cover approximate to 70-80% of the overall C-H H -C stabilization, the covalent-like charge delocalization based on depletion of electron charge from the sigma(C-H) orbitals to the inter-atomic H H region contributes notably up to 15%.