N‑Heterocyclic-Carbene Complexes Readily Prepared from Di-μ-hydroxopalladacycles Catalyze the Suzuki Arylation of 9‑Bromophenanthrene

New cyclometalated palladium complexes of general formula [Pd­(Bmim)­(X)­(C^∧N)] have been synthesized by a novel reaction route involving di-μ-hydroxo-palladacycles [{Pd­(μ-OH)­(C^∧N)}₂] (C^∧N = 2-benzoylpyridine (Bzpy), <b>I</b>, previously unreported, or C^∧N = 2-phenylpyridine (Phpy), <b>II</b>)] and 1,3-butylmethyl­imidazolium salts [HBmim]­X (X: Cl, Br, I, or saccharinate (Sacc); <b>a</b>, <b>b</b>, <b>c</b>, or <b>d</b> complexes, respectively). This simple acid–base reaction could not be achieved under identical conditions when corresponding di-μ-acetate complexes were used as starting materials. An alternative pathway to NHC/imidate complexes has also been explored by reacting <b>IIb</b> with [Ag­(Phthal)­(SMe₂)]₂ (Phthal = phthalimidate, <b>e</b>) to obtain [Pd­(Bmim)­(Phthal)­(Phpy)], <b>IIe</b>. Structural characterization by X-ray diffraction of complexes <b>Id</b>, <b>IIb</b>, <b>IId</b>, and <b>IIe</b> has confirmed the proposed formulas. The mononuclear complexes have shown to catalyze the scalable Suzuki–Miyaura cross-coupling of 9-bromophenanthrene with a wide scope of aryl boronic acids, irrespective of their electronic properties and at a very low catalyst concentration of 0.01%

N‑Heterocyclic-Carbene Complexes Readily Prepared from Di-μ-hydroxopalladacycles Catalyze the Suzuki Arylation of 9‑Bromophenanthrene

New cyclometalated palladium complexes of general formula [Pd­(Bmim)­(X)­(C^∧N)] have been synthesized by a novel reaction route involving di-μ-hydroxo-palladacycles [{Pd­(μ-OH)­(C^∧N)}₂] (C^∧N = 2-benzoylpyridine (Bzpy), <b>I</b>, previously unreported, or C^∧N = 2-phenylpyridine (Phpy), <b>II</b>)] and 1,3-butylmethyl­imidazolium salts [HBmim]­X (X: Cl, Br, I, or saccharinate (Sacc); <b>a</b>, <b>b</b>, <b>c</b>, or <b>d</b> complexes, respectively). This simple acid–base reaction could not be achieved under identical conditions when corresponding di-μ-acetate complexes were used as starting materials. An alternative pathway to NHC/imidate complexes has also been explored by reacting <b>IIb</b> with [Ag­(Phthal)­(SMe₂)]₂ (Phthal = phthalimidate, <b>e</b>) to obtain [Pd­(Bmim)­(Phthal)­(Phpy)], <b>IIe</b>. Structural characterization by X-ray diffraction of complexes <b>Id</b>, <b>IIb</b>, <b>IId</b>, and <b>IIe</b> has confirmed the proposed formulas. The mononuclear complexes have shown to catalyze the scalable Suzuki–Miyaura cross-coupling of 9-bromophenanthrene with a wide scope of aryl boronic acids, irrespective of their electronic properties and at a very low catalyst concentration of 0.01%