Infrared, Electronic Absorption, and Emission Spectra of Tris (4‐methyl‐1‐(1‐ methyl‐1H‐benzo [d]imidazol‐2‐yl)‐4H‐benzo [d]imidazo[1,5‐a]imid‐ azole‐3‐yl) methyl: Roles of Molecular Electronic States and Axial Substitution