Rhenium complexes and methods of use for treating cancer

A composition comprising a rhenium(I) complex having the following structure:

• wherein
• Re represents a rhenium ion having a +1 charge;
• represents an uncharged bidentate ligand of one of the following structures
• wherein R1, R2, R3, R4, R5, R6, R7, R8, R1a, R2a, R3a, R4a, R5a, R6a, R7a, and R8a are each independently selected from the group consisting of hydrogen atoms;
• hydrocarbon groups (R′) containing 1-6 carbon atoms;
• —ORa groups;
• —C(O)ORa groups;
• —OC(O)Ra groups;
• —C(O)Ra groups;
• and halogen atoms, wherein said hydrocarbon groups (R′) optionally include one or more heteroatoms selected from oxygen, nitrogen, and sulfur, and Ra is independently selected from hydrogen atoms and hydrocarbon groups (R′);
• and
• L1 is an isonitrile ligand of the formula CN-R wherein R is an isonitrile ligand having the following structure:
• wherein R1d and R5d are hydrogen;
• and R2d, R3d, and R4d are independently selected from hydrogen atoms, hydrocarbon groups (R′) containing 1-6 carbon atoms, —OR″ groups, —C(O)OR″ groups, —OC(O)R″ groups, —C(O)R″ groups, —NR″2 groups, —C(O)NR″2 groups, —NR″C(O)R″ groups, halogen atoms, —CN groups, and nitro groups;
• wherein the hydrocarbon groups (R′) optionally include one or more heteroatoms selected from oxygen, nitrogen, and sulfur;
• and R″ is independently selected from hydrogen atoms and hydrocarbon groups (R′);
• L2, L3, and L4 are each independently CO;
• and
• X31 represents a non-coordinating monovalent anion.