SYNTHESIS AND CHARACTERIZATION OF TRITHIENOCYCLOTRIYNE (TTC) AND ITS TETRACOBALT COMPLEX - THE 1ST EXAMPLE OF A DEHYDROANNULENE CONTAINING THIOPHENE RINGS

The planar trithienocyclotriyne (TTC) has been synthesized and structu rally characterized by X-ray crystallography. TTC crystallizes in the monoclinic space group C2/c with a = 18.481-(4) angstrom, b = 10.836(2 ) angstrom, c = 7.490(1) angstrom, beta = 112.25(3)degrees, V = 1388.3 (4) angstrom3, and Z = 4. TTC has a larger cavity size than tribenzocy clotriyne (TBC). This significantly alters the way TTC binds to transi tion metals in comparison to TBC. Reaction of TTC with Co2(CO)8 has pr oduced a tetracobalt complex in which only two of the three alkynes of TTC bind to hexacarbonyl dicobalt moieties. This complex crystallizes in the triclinic space group P1BAR with a = 10.421(2) angstrom, b = 1 2.322(2) angstrom, c = 16.110(3) angstrom, alpha = 89.42(3)degrees, be ta = 71.24(3)degrees, gamma = 66.07(3)degrees, V = 1773.1(6) angstrom3 , and Z = 2.