Crystal structure and spectral luminescent properties of monoiodo-substituted borofluoride complex with dipyrrolylmethene

The crystal structure of the boron(III) complex [BF2L] synthesized for the first time, where L− is the 3,3′,5,5′-tetramethyl-4-ethyl-4′-iododipyrrolylmethene-2,2′ monoanion (iodo-BODIPY, monoclinic crystals: a = 12.0329(6) Å, b = 15.9657(8) Å, c = 8.5080(4) Å, β = 103.753(1)°, V = 1587.64(13) Å3, Z = 4 (Z′ = 1), space group P21/c) is determined. In the structure, two pyrrol rings and the central six-membered ring containing a boron atom are in one plane, perpendicular to which a plane formed by a group of F-B-F atoms is located. The crystal packing is formed by van der Waals interactions. In the electron absorption spectra of iodo-BODIPY solutions in nonpolar solvents, unlike polar ones, a red shift up to 3–8 nm of the maximum of the first intense band is observed, for which the lgɛ value reaches ∼4.71. Along with intense chromophoric properties, the synthesized iodo-BODIPY complex is a sufficiently strong fluorophore and can be used as a fluorescent marker.