2005/09/23 by Tailuan Nguyen, Andrew D. Sutton, M. Brynda +3 · 4 citations
Materials Science · Chemistry · #Magnetism in coordination complexes #Organometallic Complex Synthesis and Catalysis #Synthesis and characterization of novel inorganic/organometallic compounds
paper · pdf · doi:10.1126/science.1116789
openalex publication_date 2005/09/23 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/31
Although in principle transition metals can form bonds with six shared electron pairs, only quadruply bonded compounds can be isolated as stable species at room temperature. Here we show that the reduction of Cr(mu-Cl)Ar'2 [where Ar' indicates C6H3-2,6(C6H3-2,6-Pri2)2 and Pr indicates isopropyl] with a slight excess of potassium graphite has produced a stable compound with fivefold chromium-chromium (Cr-Cr) bonding. The very air- and moisture-sensitive dark red crystals of Ar'CrCrAr' were isolated with greater than 40% yield. X-ray diffraction revealed a Cr-Cr bond length of 1.8351(4) angstroms (where the number in parentheses indicates the standard deviation) and a planar transbent core geometry. These data, the structure's temperature-independent paramagnetism, and computational studies support the sharing of five electron pairs in five bonding molecular orbitals between two 3d5 chromium(I) ions.