Modifying Electronic Communication in Dimolybdenum Units by Linkage Isomers of Bridged Oxamidate Dianions

Abstract

Reactions of Mo(2)(O(2)CCH(3))(DAniF)(3), DAniF = N,N'-di-p-anisylformamidinate, with oxamidate dianions [ArNC(O)C(O)NAr](2-), Ar = C(6)H(5) and p-anisyl, give pairs of isomeric compounds where the [Mo(2)] units are bridged by the oxamidate anions. For the alpha isomers, the C-C unit of the dianion is nearly perpendicular to the Mo-Mo bonds, and these are essentially perpendicular to each other. For the beta isomers, the corresponding C-C unit and the Mo-Mo bonds are essentially parallel to each other. Each type of isomer is stable in solution. The electronic communication as measured by the DeltaE(1/2) for the oxidation of each of the Mo(2) units is significantly better for the beta isomers. This is supported also by the appearance of what is conventionally called an intervalence charge-transfer band in the near infrared region upon oxidation of the beta isomers but not the alpha isomers. Molecular mechanics and DFT calculations help explain the relative conformations in the alpha isomers and the relative energy differences between the alpha and beta isomers.

Experimental and Theoretical Evidence of Aromatic Behavior in Heterobenzene‐Like Molecules with Metal–Metal Multiple Bonds

“…[21] The labile acetate group in this starting material is readily replaced, thereby resulting in the production of a species with two dimolybdenum units linked by two sulfhydryl (SH À ) anions. Subsequent oxidation by air, in concert with autodeprotonation, resulted in the S-bridged compound…”

“…] was prepared by following a published method; [21,35] commercially available chemicals were used as received.…”

Two Linear Undecanickel Mixed‐Valence Complexes: Increasing the Size and the Scope of the Electronic Properties of Nickel Metal Strings

“…These band systems are characteristic of intervalence charge-transfer transitions (IVCT). [10] Compared to pentanickel species [Ni 5 (bna) 4 Cl 2 ](PF 6 ) 2 , these IVCT bands suggest a stronger electron coupling between the metal atoms in 1 and 2. [8] The magnetic susceptibility of 1 and 2 was measured over a temperature range of 2-300 K (Figure 4 and Supporting Information Figure S5).…”

Tuning the Electronic Coupling and Electron Transfer in Mo2 Donor–Acceptor Systems by Variation of the Bridge Conformation

“…All solvents were dried and freshly distilled over appropriate drying agents under N 2 . N,N′ ‐Di( p ‐anisyl)formamidine (HDAniF) [Mo 2 (DAniF) 3 (O 2 CCH 3 )] and 1,4‐bis(hydroxymethyl)naphthalene were prepared according to published methods.…”