The field of molecular spintronics aims at exploiting the spin of electron instead of its charge in electronic devices. An example of devices is a spin valve formed by a molecular layer sandwiched between two ferromagnetic electrodes (nickel or cobalt for instance) that can act as a ON/OFF switch by controlling the relative magnetization of the two electrodes. The performance of such devices are intimately connected to the properties of the interface formed by one electrode and the first layer of molecules, also referred to as spinterface. Experimental measurements show indeed that a molecule can be magnetized or spin polarized in contact with a ferromagnetic electrode; an induced magnetization in the molecule opposite to that of the electrode induces a contact resistance which limits the device performance. In this context, the objective of this project via quantum-chemical calculations the conditions and factors dictating the magnetization of the molecules by studying the electronic properties of spinterfaces; a second aspect will be to characterize the electrical properties of molecular junctions formed by a monolayer sandwiched between two ferromagnetic electrodes, in close collaboration with experimental partners.