The quantum-mechanochemical-reaction-coordinate simulations have been performed to investigate the mechanical properties of hydrogen functionalized graphene. The simulations disclosed atomically matched peculiarities that accompany the deformation-failure-rupture process occurred in the body. A comparative study of the deformation peculiarities related to equi-carbon-core (5,5) nanographene and nanographane sheets exhibited a high stiffness of both bodies that is provided by the related hexagon units, namely benzenoid and cyclohexanoid, respectively. The two units are characterized by anisotropy in the microscopic behavior under elongation along mechanochemical internal coordinates when the later are oriented either along (zg) or normally (ach) to the C-C bonds chain. The unit feature in combination with different configuration of their packing with respect to the body C-C bond chains forms the ground for the structure-sensitive mechanical behavior that is different for zg and ach deformation modes. Hydrogenation of graphene drastically influences behavior and numerical characteristics of the body making tricotage-like pattern of the graphene failure less pronounced and inverting it from the zg to ach mode as well as providing less mechanical resistance of graphane it total.

15 pages, 9 figures, 2 tables