Design and Synthesis of Tunable Ligands with 4,4′-Bipyridyl as an Electron-Accepting Unit and Their Rhenium Complexes

Abstract

We have designed and prepared a series of rhenium complexes with 4,4′-bipyridyl as an electron-accepting unit. Electrochemical studies revealed that oxidation and reduction of these complexes occurred on the rhenium center and the 4,4′-bipyridyl skeleton, respectively. The redox potentials of the rhenium complexes are controllable by tuning the substituents on the 4,4′-bipyridyl skeleton and the coordinating groups to the rhenium center. We have also examined the reactivity of the rhenium complexes in electrochemical and photochemical CO 2 reduction.

Symmetrical Conjugated Molecular Additive for Defect Passivation and Charge Transfer Bridge in Perovskite Solar Cells

“…Under light illumination, photogenerated excitons will be separated and transport to TiO 2 electron transporting layer and spiro-OMeTAD (2,2′,7,7′-tetrakis­[ N , N -di­(4-methoxyphenyl)­amino]-9,9′-spirobifluorene) hole transporting layer and then collected by fluorine-doped tin oxide (FTO) and Au electrodes, respectively. , We employ π-conjugated BPY­[4,4] as a functional additive into the perovskite precursors and fabricate the complete device through a one-step spin-coating method (see detailed Experimental Section). The BPY­[4,4] has a unique chemical structure with two symmetric and adjacent pyridine molecules, which comprise para-position σ-donating N tails at both ends and a rigid conjugated core. , The presence of conjugation in bipyridine and conjugated polymers is demonstrated to be favorable for charge transfer process. , In addition, BPY­[4,4] is a commercially available white solid at room temperature for direct application at low cost. As shown in Figure b, BPY­[4,4] is capable of passivating the uncoordinated Pb 2+ from perovskite grains by forming coordination bonds.…”

A Rare Type of Rhenium(I) Diimine Complexes with Unsupported Coordinated Phosphine Oxide Ligands: Synthesis, Structural Characterization, Photophysical and Theoretical Study

“…In the complexes of soft metal ions the coordinated phosphine oxide moiety is commonly presented as a component of a polydentate ligand, where the phosphine oxide oxygen often plays the role of labile function in catalytic processes. [19][20][21][22][23][24][25][26] The Re I ion is a typical representative of the soft Lewis acids and similarly to the other soft metal centers coordinates the phosphine oxide mostly in combination with the other suitable soft functions, which support the Re-O bond. [22][23][24][25]27] In general, the Re I organometallic compounds attract considerable attention particularly due to their unique photophysical and photochemical characteristics, which open a way to a wide range of practical applications.…”

“…[19][20][21][22][23][24][25][26] The Re I ion is a typical representative of the soft Lewis acids and similarly to the other soft metal centers coordinates the phosphine oxide mostly in combination with the other suitable soft functions, which support the Re-O bond. [22][23][24][25]27] In general, the Re I organometallic compounds attract considerable attention particularly due to their unique photophysical and photochemical characteristics, which open a way to a wide range of practical applications. Among rhenium organometallics the tris-carbonyl diimine complexes of a general formula [Re(CO) 3 (N^N)L] n+ (n = 0,1) is a prominent family of phosphorescent complexes [28][29][30][31] with variable photophysical, photochemical and electrochemical properties, [29,32] which therefore have a great potential as biological probes and imaging reagents, [28,33,34] in OLED technology, [31] and in light-harvesting systems.…”

“…That's why the family of coordination compounds containing phosphine oxides consists mainly of the complexes with hard Lewis acids like lanthanides and actinides ions, first row transition metals,, , , and heavy metals in high oxidation states: Re V , Re III[17,18] and Au III , which are complementary partners for the hard donor oxygen in the phosphine oxides. In the complexes of soft metal ions the coordinated phosphine oxide moiety is commonly presented as a component of a polydentate ligand, where the phosphine oxide oxygen often plays the role of labile function in catalytic processes …”

“…The Re I ion is a typical representative of the soft Lewis acids and similarly to the other soft metal centers coordinates the phosphine oxide mostly in combination with the other suitable soft functions, which support the Re–O bond . In general, the Re I organometallic compounds attract considerable attention particularly due to their unique photophysical and photochemical characteristics, which open a way to a wide range of practical applications.…”