Side-on coordination of boryl and borylene complexes to cationic coinage metal fragments

Abstract

The M-(η 2 -BMn) complex [(η 5 -C 5 H 5)(OC) 2 Mn{μ-B(Cl)(tBu)Au(PPh 3)}] (2) can be functionalized via halide substitution reactions to afford isostructural complexes [(η 5 -C 5 H 5)(OC) 2 Mn{μ-B(R)(tBu)Au(PPh 3)}] (R = Ph, CCPh and NCS). It also reacts with coinage metal complexes [MCl(PPh 3)] (M = Au, Ag and Cu) in the presence of halide abstraction reagents to afford borylene-bridged heteromultinuclear complexes [{(η 5 -C 5 H 5)(OC) 2 Mn} 2 {μ 2 -B(tBu)} 2 M][BAr 4 x ] (M = Au, Ag and Cu; Ar x = 3,5-C 6 H 3 Cl 2, 3,5-C 6 H 3 (CF 3) 2). Experimental characterization as well as computational studies revealed that these complexes are best viewed as transition metal borylene complexes side-on coordinated to monovalent coinage metal cations, thus representing the first boron analogs of Stone's alkylidyne-bridged multinuclear complexes.