The synthesis of biologically relevant conjugates of Re(CO)3 using pyridine-2-carboxyaldehyde

Lipophilic Re(CO)3pyca complexes for Mid-IR imaging applications

Several Re(i)pyca conjugates incorporating long aliphatic amines have been synthesized through a one-pot methodology. The compounds have been fully characterized, and seven compounds have been structurally elucidated by single crystal X-ray diffraction. The C14 variant was probed as a potential organometallic IR dye. Large unilamellar vesicles were generated with DOPC and the C14 compound and we observed incorporation of the rhenium complex as observed by FTIR microscopy.

Systematically altering the lipophilicity of rhenium(I) tricarbonyl anticancer agents to tune the rate at which they induce cell death

Rhenium-based anticancer agents have arisen as promising alternatives to conventional platinum-based drugs. Based on previous studies demonstrating how increasing lipophilicity improves drug uptake within the cell, we sought to investigate the effects of lipophilicity on the anticancer activity of a series of six rhenium(i) tricarbonyl complexes. These six rhenium(i) tricarbonyl structures, called Re-Chains, bear pyridyl imine ligands with different alkyl chains ranging in length from two to twelve carbons. The cytotoxicities of these compounds were measured in HeLa cells. At long timepoints (48 h), all compounds are equally cytotoxic. At shorter time points, however, the compounds with longer alkyl chains are significantly more active than those with smaller chains. Cellular uptake studies of these compounds show that they are taken up via both passive and active pathways. Collectively, these studies show how lipophilicity affects the rate at which these Re compounds induce their biological activities.

Facile rhenium-peptide conjugate synthesis using a one-pot derived Re(CO)3 reagent

We have synthesized two Re(CO)3-modified lysine complexes (1 and 2), where the metal is attached to the amino acid at the Nε position, via a one-pot Schiff base formation reaction. These compounds can be used in the solid phase synthesis of peptides, and to date we have produced four conjugate systems incorporating neurotensin, bombesin, leutenizing hormone releasing hormone, and a nuclear localization sequence. We observed uptake into human umbilical vascular endothelial cells as well as differential uptake depending on peptide sequence identity, as characterized by fluorescence and rhenium elemental analysis.

Hydrazine-mediated strongly coupled Re(CO)3 dimers

We present two strongly coupled Re(CO)₃ dimers, where the metals are linked via a bis-hydrazine Schiff base ligand as well as their monomeric analogs. Strong coupling between the ligand based orbitals the dimers is observed as measured by reductive cyclic voltammetry.

Facile solid phase peptide synthesis with a Re-lysine conjugate generated via a one-pot procedure

We have synthesized a Re(CO)3-modified lysine via a one-pot Schiff base formation reaction that can be used in the solid phase peptide synthesis. To demonstrate its potential use, we have attached it to a neurotensin fragment and observed uptake into human umbilical vascular endothelial cells.