Coordination versus Insertion: On the Interaction of 5 d‐Transition Metal Carbonyl Clusters with Silver(I)

Abstract

The title silver(I) complex salts [Ag{Re2(CO)10}{Re(CO)5}2]+[Al(ORF)4]− (AgRe4; ORF=‐OC(CF3)3) and [Ag{Ir4(CO)12}2]+[Al(ORF)4]− (AgIr8) form upon reaction of Ag+[Al(ORF)4]− and the transition metal carbonyls (TMCs) Re2(CO)10 and Ir4(CO)12 respectively. The solid‐state structure of the AgRe4 cluster shows an unexpected asymmetric coordination motif, wherein the silver(I) cation has inserted into the Re−Re bond of one Re2(CO)10 moiety, while the other dirhenium carbonyl coordinates only over one metal atom towards the silver(I) cation. The AgIr8 cluster is formed by the edge‐on coordination of two Ir4 tetrahedra and the silver cation in a D2 symmetric fashion with a torsion angle of 46.5°. QTAIM analysis shows bond paths between the silver atom and the nearby metal atoms in all cases, whereas only the non‐inserted Re2(CO)10 moiety shows additional bond paths between the carbonyl ligands and the silver cation. In addition, the insertion of the Ag+ cation into the Re−Re bond in Re2(CO)10 removes the bond path between the two rhenium atoms. The EDA‐NOCV analysis suggests an increase of the interaction energy between the silver(I) cation and the respective metal carbonyls from the metal centered transition metal carbonyl (TMC) donors W(CO)6<Re2(CO)10<Os3(CO)12<Ir4(CO)12. In all cases, the dominating orbital interaction is σ‐donation [TMC]→Ag+←[TMC].

Pushing the redox potentials of deelectronators to highly positive values using solvent effects and weakly coordinating anions

“…Compared to the positive solvent limits Epos collected in Table 2, the Ag + and NO + potentials do not stretch over the full Epos limits, which the xFB solvents can tolerate (+1.82 to +2.67 V vs. E°´(Fc + /Fc, S). In addition, we have noted numerous times in synthetic applications that both, Ag + and NO + deelectronator reagents react non-innocent with substrates in xFB solutionwith complexation, 33,35,[87][88][89] substitution 30,32,34,37 or degradation 33 being the key side-or even major reactions complicating or hindering the desired reaction outcome. 64 In addition, also the magic blue salts [MB] • + [WCA] -, appraised 17 for their innocent behavior and even if partnered with the excellent WCA [pf] -, yield after deelectronations a neutral amine, that often does react non-innocent.…”

“…CH2Cl2, 1FB and 5FB, but also the more polar 2FB, 3FB and 4FB. We routinely use these WCA-reagents for syntheses with Ag + 27-29 or NO + ions, [30][31][32][33][34][35] for deelectronation [34][35][36][37][38][39][40][41][42] or dehalogenation reactions. 43,44 More than 100 groups worldwide utilize the advantageous properties of [pf]and closely related WCAs for applications in diverse fields, i.e.…”

Homoleptic Transition Metal Carbonyl Cations: Synthetic Approaches, Characterization and Follow-Up Chemistry

“…66−68 In own work, we studied TMC-complex formation of Ag + with various 5d-TMC(clusters), including W(CO) 6 , Re 2 (CO) 10 , Os 3 (CO) 12 and Ir 4 (CO) 12 (Scheme 1). 69,70 The analysis of the structure and bonding of this series elucidated that the interactions of the carbonyl ligands with Ag + are decreasing in the series, while the interaction energy with the TM metal atoms themselves gradually increases with the number of metal atoms coordinating to Ag + . Even the structures of these exotic complexes can be rationalized by the isolobality concept.…”