From straight chain to macrocyclic complexes containing mixed sulfur/nitrogen donors and coordinated 1,3-diynes

The acid-mediated reaction of [{Co2(CO)6(μ-η2-HOCH2Ctriple bond; length of mdashC–)}2] (1) with the meta- and para-substituted aminothiophenols, 3-NH2–C6H4SH and 4-NH2–C6H4SH, affords the straight chain species, [{Co2(CO)6(μ-η2-(3-NH2–C6H4S)CH2Ctriple bond; length of mdashC–)}2] (2) and [{Co2(CO)6(μ-η2-(4-NH2–C6H4S)CH2Ctriple bond; length of mdashC–)}2] (3), respectively. The molecular structure of 3 reveals the presence of two isomeric forms differing in the relative disposition of the S-aryl groups. Conversely, reaction of 1 with the ortho-substituted aminothiophenol, 2-NH2–C6H4SH, furnishes the 10-membered macrocyclic species [{Co2(CO)6}2{cyclo-μ-η2:μ-η2-CH2C2C2CH2SC6H3–NH-2}] (4) along with the linear chain complex [{Co2(CO)6(μ-η2-(2-NH2–C6H4S)CH2Ctriple bond; length of mdashC–)}2] (5). On the other hand, treatment of 1 with the ortho-substituted mercaptopyridine, 2-SH–C5H4N, in the presence of HBF4 gives the salt [{Co2(CO)6(μ-η2-(2-S–C5H4NH)CH2Ctriple bond; length of mdashC–)}2](BF4)2 (6a) in good yield; work-up in the presence of base affords the neutral complex [{Co2(CO)6(μ-η2-(2-S–C5H4N)CH2Ctriple bond; length of mdashC–)}2] (6b). Single crystal X-ray diffraction studies have been reported on 3–5 and 6a.