Janelia Fluor® 669, SE

• CAT Number: I014778
• CAS Number: 2127150-20-1
• Molecular Formula: C34H30F3N3O6SSi
• Molecular Weight: 693.76
• Purity: ≥95%
• Synonyms: 2-[3-(azetidin-1-ium-1-ylidene)-7-(azetidin-1-yl)-5,5-dimethylbenzo[b][1]benzosilin-10-yl]-4-[2-(2,5-dioxopyrrolidin-1-yl)oxy-2-oxoethyl]sulfanyl-3,5,6-trifluorobenzoate
• InChI: InChI=1S/C34H30F3N3O6SSi/c1-48(2)22-15-18(38-11-3-12-38)5-7-20(22)27(21-8-6-19(16-23(21)48)39-13-4-14-39)28-29(34(44)45)30(35)32(37)33(31(28)36)47-17-26(43)46-40-24(41)9-10-25(40)42/h5-8,15-16H,3-4,9-14,17H2,1-2H3
• InChIKey: QFHKALIQFJQJKE-UHFFFAOYSA-N
• SMILES: C[Si]1(C2=CC(=[N+]3CCC3)C=CC2=C(C4=C1C=C(C=C4)N5CCC5)C6=C(C(=C(C(=C6F)SCC(=O)ON7C(=O)CCC7=O)F)F)C(=O)[O-])C

Janelia Fluor® 669, SE（Cat No.:I014778）is a bright, far-red fluorescent dye featuring an NHS ester (SE) reactive group that covalently labels primary amines on proteins, peptides, and other biomolecules. With excitation and emission maxima around 649/669 nm, it offers excellent photostability, low background, and high signal-to-noise ratios, making it ideal for confocal microscopy, flow cytometry, and super-resolution imaging. Its far-red emission minimizes cellular autofluorescence and enables multiplexing with other fluorophores. Janelia Fluor® 669, SE is widely applied in live-cell imaging, protein tracking, and advanced fluorescence-based assays.