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

The acid-mediated reaction of [{Co 2 (CO) 6 (μ-η 2 -HOCH 2 C C–)} 2 ] ( 1 ) with the meta - and para -substituted aminothiophenols, 3-NH 2 –C 6 H 4 SH and 4-NH 2 –C 6 H 4 SH, affords the straight chain species, [{Co 2 (CO) 6 (μ-η 2 -(3-NH 2 –C 6 H 4 S)CH 2 C C–)} 2 ] ( 2 ) and [{Co 2 (CO) 6 (μ-η 2 -(4-NH 2 –C 6 H 4 S)CH 2 C C–)} 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-NH 2 –C 6 H 4 SH, furnishes the 10-membered macrocyclic species [{Co 2 (CO) 6 } 2 { cyclo -μ-η 2 :μ-η 2 -CH 2 C 2 C 2 CH 2 SC 6 H 3 –NH-2}] ( 4 ) along with the linear chain complex [{Co 2 (CO) 6 (μ-η 2 -(2-NH 2 –C 6 H 4 S)CH 2 C C–)} 2 ] ( 5 ). On the other hand, treatment of 1 with the ortho -substituted mercaptopyridine, 2-SH–C 5 H 4 N, in the presence of HBF 4 gives the salt [{Co 2 (CO) 6 (μ-η 2 -(2-S–C 5 H 4 NH)CH 2 C C–)} 2 ](BF 4 ) 2 ( 6a ) in good yield; work-up in the presence of base affords the neutral complex [{Co 2 (CO) 6 (μ-η 2 -(2-S–C 5 H 4 N)CH 2 C C–)} 2 ] ( 6b ). Single crystal X-ray diffraction studies have been reported on 3 – 5 and 6a .