Fluorescent brighteners, methods of preparation thereof, fluorescent brightener compositions, and methods of preparation and uses thereof

A compound of Formula (I) wherein R1, R2, and R3 are independently at each occurrence hydrogen, a halogen, a cyano functionality, a C1-C20 aliphatic functionality, a C3-C10 cycloaliphatic functionality or a C3-C20 aromatic functionality, with the proviso that R2 and R3 are not hydrogen when R1 is a methyl or hydrogen; R4 and R5 are independently at each occurrence hydrogen, a halogen, a cyano functionality, a C1-C20 aliphatic functionality, a C3-C10 cycloaliphatic functionality or a C3-C10 aromatic functionality; R7 and R8 are independently at each occurrence, a halogen, a cyano functionality, a C1-C20 aliphatic functionality, a C3-C10 cycloaliphatic functionality or a C3-C10 aromatic functionality; R6 is a C2-C20 aliphatic functionality, a C3-C10 cycloaliphatic functionality or a C3-C20 aromatic functionality; and "n" and "m" are each independently integers having a value of 0 to 3.