1,4,7-Trimethyl-1,4,7-triazacyclononane
1,4,7-Trimethyl-1,4,7-triazacyclononane is the aza-crown ether with the formula (CHCHNCH). This colorless liquid is the N-methylated derivative of triazacyclononane (TACN), a face-capping tridentate ligand that is popular in coordination chemistry. Although TACN is known for forming 2:1 "sandwich" complexes with many metal ions, corresponding 2:1 complexes of MeTACN are only known for Ag, Na, and K. This effect is mainly due to the greater bulk of MeTACN, which requires ions with a larger ionic radius to accommodate two ligands. Several related derivatives have been prepared with diverse substituents on nitrogen. 1,4,7-Trimethyl-1,4,7-triazacyclononane