Optimizing Nickel(II) Complex Catalysts for High-Yield Oligomerization of Cyclohexyl Isocyanide

Isocyanides, due to the divalent carbon atom present in their structure, are among the most reactive groups of compounds in organic chemistry. Unfortunately, although according to the literature they do not have acute toxicity, they have a very unpleasant odor that makes it difficult to collaborate with them. However, despite the properties mentioned, reactions of isocyanides often lead to a variety of functional materials. In this article, we present a modified method for obtaining isocyanide-based polymers that significantly reduce the release of their hazardous vapors into the environment. For the study, a series of nickel(II) metal ion complex compounds containing organic ligands (e.g., 2,2'-bipyridyl, 1,10-phenanthroline, and diglycolate anion) were synthesized and used as catalysts in the oligomerization reaction of cyclohexyl isocyanide. The obtained oligomers were subjected to quantitative and qualitative physicochemical analyses (FT-IR, MALDI-TOF-MS, TGA/DSC, and DSC), which confirmed their structure and thermal properties. Reaction yields ranged from moderate (8-52%) to extremely high (94%) for a single catalyst. The synthesized catalytic systems are new, previously undescribed isocyanide oligomerization catalysts, which successfully led to the synthesis of poly(cyclohexyl isocyanide) and allowed us to obtain materials that can be used to produce many useful polymeric materials.