A convenient route to prepare mono- and dinuclear 2-benzoylpyridine palladacycles with imidate ligands

• A new route to prepare scarce 2- benzoylpyridine palladacycles is presented.
• The basicity of [{Pd(μ-OH)(bzpy)}2] is exploited reacting with cyclic imides.
• Bridge splitting with PPh3 of dinuclear μ-NCO- imidates thus prepared is explored.
• First crystal structure reported to date of a 4,5-dichlorophthalimidate complex.

New dinuclear cyclometallated palladium complexes of general formula [{Pd(μ-NCO)(CˆN)} 2] (CˆN = 2-benzoylpyridine (bzpy) I; NCO = saccharinate (sacc) a, Phthalimidate (phthal) b or 4,5-dichlorophthalimidate (DiClphthal) c have been synthesized by a simple acid-base reaction involving the di-μ-hydroxo-precursor [{Pd(μ-OH)(bzpy)}2] recently reported. Analogous to Ic, complex IIc with CˆN = 2-phenylpyridine (phpy) II has also been prepared, meaning the first examples reported to date of complexes including 4,5-dichlorophthalimidate as ligand coordinating a metal centre. The reaction of bridged imidato precursors against triphenylphosphine to form the mononuclear N-bonded imidato derivatives of general formula [Pd(CˆN)(N-imidate)(PPh3)] IaP, IbP, IcP and IIcP has been achieved under mild conditions. The new complexes were characterized by partial elemental analyses and spectroscopic methods. Structural characterization by X-ray diffraction of Ib and IIcP, the first crystal structure of a complex containing 4,5-diClphthal that has been deposited to date on the Cambridge Structural Database, have confirmed the proposed formulae.

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