  Glaser-like coupling of terminal alkynes by thermal activation is extensively
used in on-surface chemistry. Here we demonstrate an intramolecular version of
this reaction performed by atom manipulation. We used voltage pulses from the
tip to trigger a Glaser-like coupling between terminal alkyne carbons within a
custom synthesized precursor molecule adsorbed on bilayer NaCl on Cu(111).
Different conformations of the precursor molecule and the product were
characterized by molecular structure elucidation with atomic force microscopy
and orbital density mapping with scanning tunneling microscopy, accompanied by
density functional theory calculations. We revealed partially dehydrogenated
intermediates providing insight into the reaction pathway.
