Synthesis and alkyne coordination chemistry of thiacycloalkynes

The reactions of 1,4-dichlorobut-2-yne with HS(CH2)(n)SH (n = 2-5) or HS(CH2CH2S)(n)H(n = 2-3) or HSCH2CH(OH)CH2SH under high dilution conditions in industrial methylated spirits using KOH as the deprotonating agent produce thiacycloalkynes in remarkably high yields when the 1 : 1 product is a nine-, ten- or 11-membered ring. 1,5-dithiacyclonon-7-yne, 1,5-dithiacyclonon-7-yne-3-ol, 1,6-dithiacyclodec-8-yne, 1,7-dithiacycloundec-9-yne, 1,4,7-trithiacycloundec-9-yne and 1,7-dithia-4-oxa-cycloundec-9-yne are pre pared in yields of 75%, 81%, 79%, 85%, 100% and 95% respectively. The X-ray crystal structures of 1,4-dithiacyclooct-6-yne and 1,6-dithiacyclodec-8-yne have been determined. Selective coordination of the alkyne functionality is demonstrated by the reaction of 1,4,7,10-tetrathiacyclotetradec-12-yne with [Co-2(CO)(8)] to afford a monoalkyne hexacarbonyldicobalt complex and by the reaction of 1,4,7-trithiacycloundec-9-yne with [Mo(CO)(2)(S(2)CNMe(2))(2)] to afford a bisalkynebis(dithiocarbamate)molybdenum complex. A base-catalysed rearrangement of 1,4,7-trithiacycloundec-9-yne affords 2-enyl-1,4,7-trithiacyclonon-2-ene which is an effective ligand for Ag+.