Hydrogen bonding of tricyclohexylgermanium hydroperoxide in cocrystals with DABCO N-oxide and Ph₃PO

Hydrogen bonds between hydroperoxo ligands of p-block element complexes and surface functionalities of substrate particles are considered essential for sol-gel processing using hydrogen peroxide, which is effectively implemented to prepare 2D functional materials. Cocrystals of molecular organoelement hydroperoxo complexes appear to be the suitable model systems to study such interactions. This paper reports the structural and hydrogen bonding theoretical characterization of tricyclohexylgermanium hydroperoxide cocrystals with triphenylphosphine oxide, Cy₃GeOOH·Ph₃PO (I), and DABCO N-oxide, 2(Cy₃GeOOH)·(DABCO N-oxide) (II). Additionally, cocrystal of triphenylgermanium hydroxide and DABCO N-oxide, Ph₃GeOH·(DABCO N-oxide) (III), was synthesized. Crystallographic analysis demonstrated the comparable geometric parameters of hydrogen bonds donated by OOH (I, II) and OH ligands (III). Periodic DFT computations followed by Bader analysis of crystalline electron density revealed close energy values (53.2–56.2 kJ mol^{− 1}) for the corresponding O–H⋯O⁻–N⁺ and O–H⋯O=P hydrogen bonds in I–III and allowed to classify them as intermediate interactions. Isolated cluster DFT calculations of the analogous adducts of OOH and OH organogermanium complexes showed the stronger hydrogen bonds for the former (by 6.6 or 10.3 kJ mol^{− 1}), confirming the similarity of coordination and simple covalent hydroperoxo compounds.