4,7,13,16,21,24-Hexaoxa-1,10-diazoniabicyclo[8.8.8]-hexacosane Bis[tetrabromoiron(III)]: Synthesis and Crystal Structure

A new complex salt, 4,7,13,16,21,24-hexaoxa-1,10-diazoniabicyclo8.8.8]-hexacosane bistetrabromoiron(III)], H₂(Crypt-222)]²⁺ · 2FeBr₄]^? (I), is synthesized, and its crystal structure is studied using X-ray diffraction analysis (space group C2, a = 13.605 Å, b = 11.144 Å, c = 12.977 Å, β = 117.27°, Z = 2, direct method, full-matrix least-squares method in the anisotropic approximation, R = 0.074 for 2673 reflections, CAD4 automated diffractometer, λMoK _αradiation). In the structure of salt I, the tetrahedral FeBr₄]^? anion is somewhat distorted. The 2.2.2-cryptand dication (with two protonated nitrogen atoms) lies on the crystallo-graphic axis 2and contains N⁺-H(?O)₃ trifurcate hydrogen bonds.