1,1′-Diheptyl-4,4′-bipyridinium dibromide6159-05-330 % similar 1-Butyl-4-methylpyridinium bromide65350-59-630 % similar (5-Bromopentyl)trimethylammonium bromide15008-33-030 % similar Tetramethylammonium bromide64-20-030 % similar