Three-Coordinate Pd(0) with Rare-Earth Metalloligands: Synergetic CO Activation and Double P–C Bond Cleavage-Formation Reactions

Abstract

Metalation of β-diketiminato rare-earth metal complexes L nacnac Ln(PhNCH 2 PPh 2 ) 2 (Ln = Y, Yb, Lu) with (COD)Pd(CH 2 SiMe 3 ) 2 afforded three-coordinate Pd(0) complexes supported by two sterically less bulky phosphines and a Pd → Ln dative interaction. The Pd(0) center is prone to ligation with isonitrile and CO; in the latter case, the insertion of a second CO with the Y−N bond was assisted via a precoordination of CO on the Pd(0) center, which led to the formation of an anionic Pd(0) carbamoyl. The reaction of the Pd−Y complex with iodobenzene showed a remarkable double P−C bond cleavage-formation pathway within the heterobimetallic Pd−Y core to afford (Ph 3 P) 2 PdI(Ph), imine PhNCH 2 , and a β-diketiminato yttrium diiodide. In the related reaction of L nacnac Y(PhNCH 2 PPh 2 ) 2 with (Ph 3 P) 2 PdI(Ph), the P−C bond cleavage following with a N−C bond formation was observed. Computational studies revealed a synergetic bimetallic mechanism for these reactions.

Dinitrogen Complexes of Cobalt(−I) Supported by Rare-Earth Metal-Based Metalloligands

“…The ligand precursor LH 3 was synthesized via a facile reaction between tris -amine and 3 equiv of Ph 2 PCH 2 OH . Treatment of LH 3 with 1 equiv of rare-earth metal tris-alkyl precursors (Me 3 SiCH 2 ) 3 Ln­(THF) 2 in toluene afforded the tris -amide complexes L Ln ( 1 – 5 ) in ca.…”

“…We envisioned that the rare-earth metal ions are suitable for metalloligands due to their adjustable Lewis acidity according to the variation of ionic radii from Sc­(III) (0.745 Å) to La­(III) (1.032 Å), which would provide an interesting electronic perturbation via a flexible M → Ln bonding interaction . Although success was achieved recently with the assembly of Ln­(III/II)–M(0) (M = Ni, Pd, Pt) complexes that exhibited M → Ln dative interactions and heterobimetallic reactivities, , profound challenges exist with Ln–Co complexes, probably due to the highly oxo-, halophilic property of the hard Ln­(III) ions, and the shortage of suitable low-valent cobalt precursors in contrast to those commercially available for Ni(0) and Pd(0). To the best of our knowledge, the closest system achieved so far is a Zr­(IV)–Co­(−I) complex (Figure C) and its Ti analogue, and the complex featuring a Ln–Co bond has not been reported.…”

Recent advances in heterometallic clusters with f-block metal–metal bonds: synthesis, reactivity and applications

“…In addition, the reactivity of RE-TM bonds supported by mixed b-diketiminato and the N-CH 2 -P skeleton was investigated by the Cui group. 70,71 Heterobimetallic Y-Ni complex 79 could react with epoxide and nitrile, leading to the formation of complexes 80 and 81 via the ring-cleavage of epoxide and nitrile inserted to the coordinated imine, respectively (Scheme 31). The Y-Pd bond in complex 82 could react with excess of CO and one molecule of CO insert into the Y-N bond, leading to the formation of complex 83.…”

Structure and bonding patterns in heterometallic organometallics with linear Ln–Pd–Ln motifs

“…The distance can be compared with the short reported Pd-Yb distances of 2.7879(6) Å 51,53 and 2.8397(4) Å. 52 The remaining brown powder can be crystallized in toluene at cold and corresponds to a coupling product, already published by our group, 45 Please do not adjust margins Please do not adjust margins of 2 and 3 with other non-coordinating reductants (CoCp* 2, sodium naphthalene) did not lead to the formation of 4 and 5, but to unidentified products, demonstrating the importance of the divalent lanthanide fragment in the occurrence of this reduction reactivity.…”