A novel chelatofore functionalized spiropyran of the 2-oxaindane series.

A novel chelatofore functionalized spiropyran of the 2-oxaindane series, namely 8-formyl-7-hydroxy-3',3'-dimethylspiro[2H-chromene-2,1'(3'H)-2-benzofuran], C(19)H(16)O(4), is reported. In the crystalline state, dimers are formed as a result of the pi-pi stacking of aromatic groups of the 2H-chromene part of the molecule and C-H...O interactions. The C(spiro)-O bond length in the pyran ring is 1.4558 (10) A, which is longer than or equal to the bond length in thermo- and photochromic 2-oxaindane spiropyrans synthesized previously, except for the 7,8-benzo/6-NO(2) derivative, in which this bond length is 1.465 (2) A.