Organometallic Probe for the Electronics of Base‐Stabilized Group 11 Metal Cations. Issue 35 (14th July 2015)

• Record Type: Journal Article
• Authors: Braunschweig, Holger; Ewing, William C.; Kramer, Thomas; Mattock, James D.; Vargas, Alfredo; Werner, Christine
• Is Part Of: Chemistry. Volume 21:Issue 35(2015)
• Page Start: 12347
• Page End: 12356
• Publication Date: 2015-07-14
• Subjects: boron -- carbenes -- coinage metals -- manganese -- metal–metal interactions -- structure elucidation; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201500788
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: A number of trimetalloborides have been synthesized through the reactions of base‐stabilized coinage metal chlorides with a dimanganaborylene lithium salt in the hope of using this organometallic platform to compare and evaluate the electronics of these popular coinage metal fragments. The adducts of Cu I, Ag I, and Au I ions, stabilized by tricyclohexylphosphine (PCy3 ), N ‐1, 3‐bis(4‐methylphenyl)imidazol‐2‐ylidene (ITol), or 1‐(2, 6‐diisopropylphenyl)‐3, 3, 5, 5‐tetramethylpyrrolidin‐2‐ylidene (CAAC), with [{Cp(CO)2 Mn}2 B] − were studied spectroscopically, structurally, and computationally. The geometries of the adducts fall into two classes, one symmetric and one asymmetric, each relying on the combined characteristics of both the metal and ligand. The energetic factors proposed as the causes of the structural differences were investigated by ETS‐NOCV (extended transition state‐natural orbitals for chemical valence) analysis, which showed the final geometry to be controlled by the competition between the tendency of the coinage metal to adopt a higher or lower coordination number and the willingness of the cationic fragment to participate in back‐bonding interactions. Abstract : Coining it! The complete set of adducts of monocationic coinage metals (Cu, Ag, Au) with an anionic dimanganaborylene complex, stabilized by Lewis bases (PCy3, NHC, CAAC), have been synthesized and studied. The differences in the observed structures of the products are indicative of each metal's propensity for a higher or lower coordination number and the electronic environment provided by the ligand (see scheme).