A Multiply Bonded Trigonal‐Planar Bismuth(III) Complex: Prodigious Lewis Acidity, Solvatochromism, Etherification, and Semiconducting Characteristics

Abstract

The formation of a hitherto unknown 4-center, 6π-conjugated trigonal-planar complex, [Bi{Cr(CO) } ] (1), is reported, in which the oxidation state of the Bi atom is +3, as evidenced by XAS, XPS, and DFT calculations. The Bi atom in 1 has dual donor and acceptor properties in its bonding mode. In contrast to the mild Lewis acidity of Bi , the central Bi in 1 functions as a prodigious Lewis acid site to exhibit strong affinity toward F ions, unique solvatochromic properties, intriguing etherification through the C-O bond cleavage of alcohols, and surprising semiconducting characteristics with an ultra-narrow optical band gap of 1.02 eV, which can be attributed to the intermolecular Bi⋅⋅⋅O and O⋅⋅⋅O interactions in the solid state. The tetrahedral Fe(CO) -adduct [{Fe(CO) }Bi{Cr(CO) } ] (1-Fe) allowed the selective demetallation to afford the isoelectronic multiply bonded BiCr -complex 1 and the BiCr Fe-complex, [Bi{Cr(CO) } {Fe(CO) }] (2), which may open a novel pathway for the design of the heterometal-incorporated trigonal-planar Bi-Cr complexes.

Synthesis and Characterization of Strongly Solvatochromic Molybdenum(III) Complexes

“…Widely studied group 8 (Fe, Ru, and Os) cyanide, cyanamide, cyclopentadienyl, and ammine complexes show strong solvatochromism over a wide range of the visible spectrum. − Interestingly, when the absorption bands of these compounds are correlated with solvent polarity, protic solvent environments form a distinctly different correlation than those with aprotic solvents, indicating a hydrogen bonding interaction with the metal complex. However, some metal complexes have been shown to display significant solvatochromism free of coordination, including zero-valent group 6 (Cr, Mo, and W) diimine or dithione carbonyl complexes, ,− zinc octa­(carbazolyl)­phthalocyanine, and group 10 (Pt, Pd, and Ni) complexes. − Group 6 carbonyl compounds have been widely studied and shown to be both neutral and highly polar in the ground state, making them fairly soluble in a range of organic solvents. These complexes are characterized by negative solvatochromism resulting from an excited state with a lessened dipole moment.…”