Tris(2,2'-bipyridine)ruthenium(II)-NHS ester, hexafluorophosphate salt
[CAS# 161698-59-5]

Identification

• Classification: Organic raw materials >> Organometallic compound >> Organic ruthenium
• Name: Tris(2,2'-bipyridine)ruthenium(II)-NHS ester, hexafluorophosphate salt
• Synonyms: TAG NHS ester; Ruthenium(2+), bis(2,2'-bipyridine-?N1,?N1')[1-[4-(4'-methyl[2,2'-bipyridin]-4-yl-?N1,?N1')-1-oxobutoxy]-2,5-pyrrolidinedione]-, (OC-6-33)-, hexafluorophosphate(1-) (1:2)
• Molecular Formula: C₃₉H₃₅F₁₂N₇O₄P₂Ru
• Molecular Weight: 1056.74
• CAS Registry Number: 161698-59-5
• SMILES: O=C(CCCC1=CC(C2=CC(C)=CC=[N]2[Ru+2]345([N]6=C(C7=[N]5C=CC=C7)C=CC=C6)[N]8=C(C9=[N]4C=CC=C9)C=CC=C8)=[N]3C=C1)ON%10C(CCC%10=O)=O.[F-][P+5]([F-])([F-])([F-])([F-])[F-].[F-][P+5]([F-])([F-])([F-])([F-])[F-]

Discovory and Applicatios

Tris(2,2'-bipyridine)ruthenium(II)-NHS ester, hexafluorophosphate salt, is a coordination complex based on the ruthenium(II) center coordinated by three 2,2'-bipyridine ligands, with one ligand functionalized by an N-hydroxysuccinimide (NHS) ester group. This compound is typically isolated as the hexafluorophosphate salt to improve its stability and solubility properties.

The core complex, tris(2,2'-bipyridine)ruthenium(II), was discovered in the mid-20th century and became prominent due to its strong luminescent properties and redox activity. It absorbs visible light and emits luminescence, characteristics that have made it widely used in photochemistry, electrochemistry, and as a probe in biological imaging and sensing.

The addition of the NHS ester functional group to one bipyridine ligand represents a chemical modification aimed at facilitating covalent attachment to biomolecules. NHS esters are well known for their ability to react selectively with primary amine groups, commonly found in proteins, peptides, and other biological molecules. This reactivity allows for the formation of stable amide bonds, enabling the labeling or conjugation of the ruthenium complex to biomolecules.

Tris(2,2'-bipyridine)ruthenium(II)-NHS ester, hexafluorophosphate salt, is primarily used as a bioconjugation reagent in the fields of chemical biology and bioanalytical chemistry. Its photophysical properties make it an excellent luminescent tag for studying protein interactions, localization, and dynamics. When conjugated to biomolecules, the ruthenium complex can be excited with visible light and detected through its characteristic luminescence, providing sensitive and specific signals in imaging and detection assays.

The hexafluorophosphate counterion is chosen because it stabilizes the positively charged ruthenium complex and generally enhances the solubility of the compound in organic solvents, which is beneficial for various synthetic and labeling protocols.

Applications of this compound include fluorescent labeling in microscopy, time-resolved luminescence assays, and electrochemiluminescence techniques used in biosensors and diagnostic tools. The NHS ester facilitates site-specific labeling under mild conditions, preserving the native function of biomolecules while introducing a luminescent reporter.

In research, tris(2,2'-bipyridine)ruthenium(II)-NHS ester is employed to investigate protein conformational changes, enzyme activities, and cellular uptake of biomolecules. The combination of robust luminescence, chemical stability, and selective bioconjugation makes this complex a versatile tool in the study of biological systems.

The compound is typically prepared by derivatizing one bipyridine ligand of the tris(2,2'-bipyridine)ruthenium(II) complex with an NHS ester functionality, followed by isolation as the hexafluorophosphate salt. This salt form is favored for its favorable crystallinity and handling properties.

In summary, tris(2,2'-bipyridine)ruthenium(II)-NHS ester, hexafluorophosphate salt, is a ruthenium-based luminescent complex modified to allow covalent attachment to biomolecules via NHS ester chemistry. Its discovery is rooted in the longstanding use of ruthenium bipyridine complexes in photochemistry and luminescence, with the NHS ester modification extending its utility into chemical biology and bioanalytical applications. Its primary uses revolve around fluorescent labeling, bioimaging, and biosensing, where it provides sensitive detection and detailed insights into molecular interactions and functions.