Surface modification with multiphilic ligands at detectable well defined active positions of nano-object of giant wheel shaped molybdenum blue showing third-order nonlinear optical properties

Abstract

The reaction of an aqueous solution of sodium molybdate with l-tyrosine in the presence of reducing agent results in the formation of a new compound of the formula of Na 8Co 3[Mo VI 126 Mo V 28O 462H 14(H 2O) 46(HOC 6H 4CH 2CH( NH 3 + )COO −) 12]·ca. 200H 2O. The compound contains nanosized ring-shaped clusters with tyrosine ligands possessing different types of functional groups (one –CO 2, one – NH 3 + and one –ArOH) coordinated through the carboxylate groups at the active sites of the inner cavity. Importantly, the result demonstrates that not only active sites/areas of the cluster surface under a specified condition can be directly monitored and detected but also novel type surfaces within the cavity of a nano-structured ring-shaped cluster can be generated simultaneously. The nonlinear optical properties of the new cluster are studied using the well-known Z-scan technique at a wavelength of 532 nm with laser pulse duration of 18 ps. The results show that the new cluster exhibits interesting self-focusing nonlinear optical response with the real and imaginary parts of the third-order nonlinear optical susceptibility χ (3) being 1.069 × 10 −13(esu) and 2.529 × 10 −15(esu), respectively, which may find application in material science.