Structural systematics of some trinuclear alkynyl and diynyl Group 11 complexes containing dppm [dppm = CH2(PPh2)2]

•Survey of 39 Cu and Ag complexes of dppm and alkynes or diynes.•Triangular Cu, Ag clusters containing alkynyl, diynyl groups show significant variability.•Structural systematics of bonding of alkynyl, diynyl in Cu, Ag complexes.•Discussion of steric effects of ligands on molecular structures.•Conformational effects of dppm ligands.