Tin(IV) cyanoximates: synthesis, characterization, and cytotoxicity

Area of Science:

• Organometallic Chemistry
• Medicinal Chemistry
• Materials Science

Background:

• Organotin(IV) compounds exhibit notable cytotoxicity against various cancers.
• Cyanoximes possess diverse biological activities, including antimicrobial and growth-regulation effects.
• The antiproliferative potential of cyanoxime-containing organotin(IV) complexes remains unexplored.

Purpose of the Study:

• To synthesize novel organotin(IV) cyanoximate complexes.
• To characterize these new compounds using advanced spectroscopic and analytical techniques.
• To evaluate the in vitro antiproliferating activity of the synthesized complexes against human cancer cell lines.

Main Methods:

• Synthesis of 19 organotin(IV) complexes with nine cyanoxime ligands via heterogeneous metathesis.
• Characterization using UV-visible, IR, NMR (1H, 13C), and 119Sn Mössbauer spectroscopy.
• X-ray diffraction analysis to determine crystal structures of mononuclear and tetranuclear complexes.

Main Results:

• Two distinct structural types of tin(IV) cyanoximates were identified: mononuclear R4-xSnLx and tetranuclear R8Sn4(OH)2O2L2 species.
• The tetranuclear complexes feature a planar [Sn4(OH)2O2]2- core with bridging oxo and hydroxo groups.
• Two dibutyltin(IV) cyanoximates exhibited in vitro cytotoxicity against HeLa and WiDR cancer cells, matching or exceeding cisplatin's efficacy.

Conclusions:

• This study presents the first synthesis and characterization of organotin(IV) cyanoximate complexes.
• The crystal structures reveal unique coordination environments for tin(IV) and the role of cyanoximate ligands.
• The promising antiproliferative activity of specific dibutyltin(IV) cyanoximates warrants further investigation for cancer therapy.