Functionalized graphene oxides stabilizing Cu+1 ions under ambient O2

Abstract Novel silanized-Graphene Oxide hybrids were synthesized using alkoxy-substituted organo-silane, R-LSi, chemistry. SEM, XRD and Raman data show that the so-derived R-LSi-GO hybrids retain their stacked structure. However the interlayer d-spacing varies in a non-linear manner vs. the size of the R-LSi moieties. A – so far unforeseen - reaction mechanism is unraveled dictating that the [Si]/[R-L] ratio may drive at three distinct types of functionalized GO-hybrids. Based on this, taking into account the type of the L-moiety, a model is discussed that describes consistently the observed structural trends. Chemical reactivity and accessibility of the surface anchored vs. intercalated functionalities has been quantitatively mapped. Using Electron Paramagnetic Resonance spectroscopy, it is shown that these R-LSi-GO hybrids bear considerable e-donating capacity, reducing Cu2 + atoms to Cu1 +, forming [Cu1 +-R-LSi-GO] adducts that remain stable under ambient O2. The present data reveal that the R-LSi-GO -matrix is not simply a net that holds the Cu-atoms, but rather an active e-donating nanodevice that, when functionalized with the appropriate e-donating groups, creates a reducing microenvironment persisting under ambient O2. As a result R-LSi-GO hybrids provide e-donating nanoplatforms, able to stabilize the elusive Cu1 + species under ambient O2.