| 主权项 |
1. A security element comprising a helical metallic complex as a security feature material, the helical metallic complex comprising at least three metal atoms, M1, M2 and M3, two of said metal atoms M1 and M3 are selected from Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Lu, Hf, Ta, W, Re, Os, Ir, Pt, La, Ce, Pr, Nd, Pm, Sm Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, metal M1 and M3 being the same metal atoms, and at least one metal atom M2 being selected from Tm, Er, Yb, wherein said complex comprises at least two benzimidazole molecules, so as to form a complex with said metal atoms, wherein each of said benzimidazole molecules is bound to at least two metal atoms, wherein said benzimidazole molecules assume a helical conformation and said metals are bound in the center of the helical conformation, wherein the metal M2 is situated between metals M1 and M3; and the metallic complex absorbs light in the spectrum of infrared and emits light in the visible spectrum. |
