Self-Assembly of Cationic, Hetero- or Homonuclear Ruthenium(II) Macrocyclic Rectangles and Their Photophysical, Electrochemical, and Biological Studies

Abstract

A series of supramolecular rectangles, including two mixed-metal Ru/Pt complexes, have been formed by the coordination-driven self-assembly of a range of arene-Ru “molecular clip” acceptors (1a-1d) with rigid dipyridyl-based ligands (2a-2d) over the course of 10 hours in solution. The isolated products were characterized by multinuclear NMR (1H and 13C or 31P), HR-ESI-MS and an X-ray diffraction study to support the ascribed two-component rectangular structures. The rectangles were further characterized by UV-Vis and fluorescence studies. The redox behaviors of rectangles 3ca and 3da were also determined using cyclic voltammetry. Additionally, the antitumor activities of the suite of rectangles were determined against various human cancer cell lines and significant activity was shown by complexes 3ca, 3da, 3cb, 3cc and 3cd, with IC50 values as low as 2.65 μM.

Biomedical and Biochemical Applications of Self-Assembled Metallacycles and Metallacages

“…The most straightforward of these assemblies incorporate the 4-pyridyl building blocks depicted in Figure 5. 22 In vitro anticancer activities were assessed using four cancer cell lines, SK-hep-1 (liver), HeLa (ovarian), HCT-15 (colon), and AGS (gastric). Of the eleven SCCs investigated, seven exhibited activity, as summarized in Table 2.…”

Heterometallic Multinuclear Complexes as Anti‐Cancer Agents‐An Overview of Recent Developments

“…The Pt II ‐Ru III complexes, IT127 and AH‐197 , and the macrocyclic rectangles investigated by Chi and colleagues . The IC 50 (µM) values reported are shown below the chemical structures.…”

“…Chi and colleagues followed the second strategy and reported a series of self‐assembled multinuclear macrocyclic rectangles. These compounds consisted of two fragments, a Ru‐arene acceptor and a rigid Pt‐containing containing metalloligand consisting of two pyridyl units and were shown to be stable in the presence of DMSO.…”

“…Among the compounds reported, the heteronuclear Pt II ‐Ru II ‐arene metalla‐rectangles, 3 and 4 (Figure ), were more cytotoxic than the monometallic platinum rectangles. Although no mechanistic investigations were reported, it was suspected that the compounds interact via a mechanism different from that of cisplatin given its relatively to good activity against cell lines in which cisplatin displayed poor cytotoxicity, especially the colon cancer cell line, HCT‐15 …”

Coordination-driven self-assembly of discrete Ru6–Pt6 prismatic cages

“…Our group and others have contributed substantially to the chemistry of self-assembled homometallic ruthenium architectures and their applications [100,102–108]. In broadening this research scope, herein, we describe the coordination-driven self-assembly of two new Ru–Pt heterometallic prismatic cages 3a and 3b obtained from the reaction of two arene–ruthenium(II) clips 1a and 1b and tritopic platinum(II) metalloligand 2 in methanol/chloroform mixture in 3:2 ratio (Scheme 1).…”