Luminescent conjugates between dinuclear rhenium complexes and 17α-ethynylestradiol: synthesis, photophysical characterization, and cell imaging

Abstract

New luminescent conjugates between dinuclear rhenium complexes and an estradiol moiety.

Replacement of the phosphodiester backbone between canonical nucleosides with a dirhenium carbonyl “click” linker—a new class of luminescent organometallic dinucleoside phosphate mimics

“…This broad, unstructured emission was assigned to phosphorescence from the lowest 3 MLCT. 61,65,66 The long decay times typical of triplet emissions further substantiate this assignment.…”

“…370 nm owing to metal-to-ligand (dπ(Re)–π*(pyridiazine)) charge transfer states ( 3 MLCT). 61,65 At higher energies ( ca. 260 nm) an intense band assigned to the pyridazine intraligand π–π* transitions was present.…”

“…This emission is assigned to the lowest triplet state of the metal-to-ligand charge transfer ( 3 MLCT) character resulting from a d(Re 2 (μ-Cl) 2 (CO) 6 ) → π*( pyridazine) electronic transition. 65,67 Luminescent [Re 2 (μ-Cl) 2 (CO) 6 (μ-1,2-pyridazine)] conjugates with estradiol, 65 glycodendrons, 63,64 and peptide nucleic acids (PNA) 61,62 have been reported in the literature e.g., as probes for cell imaging which encouraged us to use them as confocal microscopydetectable labels in the course of the studies reported here.…”

“…Dinuclear rhenium 1,2-diazine complexes have generally received significantly less attention than mononuclear Re(I)-carbonyl complexes. [61][62][63][64][65][66][67] Like the majority of their mononuclear Re(I)carbonyl counterparts, they exhibit strong phosphorescence in the range of ca. 550-620 nm.…”

Design of Rhenium Compounds in Targeted Anticancer Therapeutics

“…The combined CoMSIA and polar volume model ranked correctly the ligands in order of increasing relative binding affinities, illustrating the utility of this method as a prescreening tool in the development of novel Re--based estrogen receptor ligands [112]. (2-Pyridyl)hydrazono-Re(CO) 3 complex bound to the potent natural estrogen 17-estradiol through a ethynyl linker was synthetized as a potential probe for targeting estrogen receptors [113,114]. Likewise, a folate receptor probe was designed by coupling {[bis(quinolin-2-ylmethyl)amino]-5-valeric acid}Re(CO) 3 with folic acid [115].…”