Carbene-Anchored Boryl- and Stibanyl-Phosphaalkenes as Precursors for Bis-Phosphaalkenyl Dichlorogermane and Mixed- Valence AgI/AgII Phosphinidenide

Cyclic alkyl(amino) carbene (cAAC)-anchored boryl-and stibanyl-phosphaalkenes with general formula cAAC = P-ER2 [E = B, R = (NiPr2)(2) (3a-c); E = Sb, R = 2,4,6-triisopropylphenyl (5a-b)] have been synthesized and utilized as precursors for the bis-phosphaalkenyl dichlorogermane [(cAAC = P)(2)GeCl2] (6) and the first molecular example of a neutral polymeric mixed-valence Ag-I/Ag-II phosphinidenide complex [(cAACP)(2)(Ag4AgCl4)-Ag-I-Cl-II](n) (7). All compounds have been characterized by single-crystal X-ray diffraction and further investigated by nuclear magnetic resonance (NMR), mass spectrometric analysis, and UV-vis/fluorescence measurements. The paramagnetic complex 7 has been characterized by ESR spectroscopy. Cyclic voltammetry studies of compounds 3/5 have suggested possible one-electron quasi-reversible reductions, indicating their redox noninnocent behavior in solution. Quantum chemical studies revealed the electron-sharing nature of the P-B and P-Sb sigma bonds in compounds 3 and 5, and the polar CcAAC = P bonds in compounds 3, 5, and 6 prevailing their phosphaalkene structures over phosphinidenes.

Automated summary

By synthesizing and characterizing a series of novel cAAC-anchored boryl-and stibanyl-phosphaalkenes, it has been found that these compounds exhibit redox noninnocent behavior in solution, while revealing their molecular structures and properties.