SiRhius® 650 NHS ester
| Cat. # | Quantity | Price | Lead time | Buy this product |
|---|---|---|---|---|
| 11S20 | 1 mg |
$280.00
|
in stock | |
| 31S20 | 10 mg |
$1380.00
|
in stock | |
| 51S20 | 50 mg |
please inquire
|
12 days |
SiRhius® 650 NHS ester (also known as SiR dye 1) is a far-red fluorescent dye designed for efficient covalent labeling of biomolecules containing primary amines, such as proteins, peptides, and antibodies. The NHS ester group readily reacts with ε-amino groups of lysine residues or N-terminal amino groups under mild aqueous conditions, forming stable amide bonds.
SiRhius® 650 belongs to the family of silicon-rhodamine (SiR) dyes and combines long-wavelength fluorescence with high molar absorptivity, excellent photostability, and minimal photo- and cytotoxicity, making it indispensable for super-resolution microscopy (STED, SIM, PALM/STORM) and long-term live cell imaging. Unlike many cyanine dyes, SiRhius 650 is stable under alkaline conditions.
The far-red fluorescence of the dye does not overlap with cellular autofluorescence, which is important for fluorescence microscopy, flow cytometry, and other bioanalytical methods.
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General properties
| Appearance: | green crystals |
| Molecular weight: | 569.69 |
| CAS number: | 1808181-14-7 |
| Molecular formula: | C31H31N3O6Si |
| IUPAC name: | (2,5-dioxopyrrolidin-1-yl) 3',7'-bis(dimethylamino)-5',5'-dimethyl-1-oxospiro[2-benzofuran-3,10'-benzo[b][1]benzosiline]-5-carboxylate |
| Solubility: | ethyl acetate, methanol, acetonitrile, DMF, DCM, DMSO |
| Quality control: | NMR 1H and HPLC-MS (95+%) |
| Storage conditions: | 12 months after receival at -20°C in the dark. Transportation: at room temperature for up to 3 weeks. Desiccate. |
| MSDS: | Download |
| Product specifications |
Spectral properties
| Excitation/absorption maximum, nm: | 646 |
| ε, L⋅mol−1⋅cm−1: | 112000 |
| Emission maximum, nm: | 669 |
| Fluorescence quantum yield: | 0.57 |
| CF260: | 0.07 |
| CF280: | 0.02 |


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