I work about Frustrated Lewis Pais, there are the combinaison of  Lewis acid and bulky lewis base, both very bulky. There isn't a covalent bond between them because of the congested but a dispersion interaction. I know Dispersion interaction is created by the electron which move creating  instantaneous dipole , so this dispersion is between an instantaneous dipole and induced dipole. This is in the Van der Waals bonds, weak, no directional, and on 1/R6 so long rang. For FLPs this interaction leads to the cohesion of them. 

Have you any complements for me, or perhaps easier explanation? I think it's a little vague. Thanks a lot, Anaëlle