Supramolecular anion⋯anion motifs in dichromate hybrid salts and their detection through 53Cr SSNMR.

Experimental evidence shows that dichromate anions of organic dichromate salts form in the solid supramolecular anion⋯anion adducts via short and nearly linear contacts wherein chromium of one anion and oxygen of another anion act as an electrophile and a nucleophile, respectively. DFT calculations and other computational methods prove the attractive nature of these interactions that can be considered wolfium bonds (WfBs), the σ-hole bonds wherein the electrophile is a group 6 element. The 53Cr WURST-QCPMG SSNMR spectra reveal a clear difference in the breadth of the powder patterns of salts wherein anions interact with each other via WfBs relative to salts wherein no WfB is present. If this breadth increase is directly related to the presence of anion-anion contacts, this unconventional technique allows detection of WfB presence in samples which cannot be studied via single crystal X-ray analyses.