Reactivity of bulky tris(phenylpyrazolyl)methanesulfonate copper(I) complexes towards small unsaturated molecules

Reaction of the tris(3-phenylpyrazolyl)methane sulfonate species (TpmsPh)Li with the copper(I) complex [Cu(MeCN)4][PF6] affords [Cu(TpmsPh)(MeCN)] 1. The latter, upon reaction with equimolar amounts of cyclohexyl- (CyNC) or 2,6-dimethylphenyl (XylNC) isocyanides, or excess CO, furnishes the corresponding Cu(I) complexes [Cu(TpmsPh)(CNR)] (R = Cy 2, Xyl 3) or [Cu(TpmsPh)(CO)] 4. The ligated isocyanide in 2 or 3 (or the acetonitrile ligand in 1) is displaced by 3-iminoisoindolin-1-one to afford 5, the first copper(I) complex containing an 3-iminoisoindolin-1-one ligand. The ligated acetonitrile in 1 undergoes nucleophilic attack by methylamine to give the amidine complex [Cu(TpmsPh){MeC(NH)NHMe}] 6, whereas only the starting materials were recovered from the attempted corresponding reactions of 2 and 3 with methylamine. Complexes 1 or 6 form the trinuclear hydroxo-copper(II) species [(μ-Cu){Cu(μ-OH)2(TpmsPh)}2] 7 upon air oxidation in moist methanol. In all the complexes the scorpionate ligand facially caps the metal in the N,N,O-coordination mode.

Graphical abstractThe bulky scorpionate (TpmsPh)− exihibits a strong N,N,O-coordination ability towards Cu (I) forming Cu-scorpionate centres that add small unsaturated molecules.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Mono and poly copper complexes bearing a sterically hindered scorpionate. ► sulfonate-functionalized scorpionate as an N,N,O-chelator to copper. ► Copper (I)–acetonitrile complex as a versatile species in coordination chemistry.