A 4,5‐Diphosphino‐Substituted Imidazolium Salt: A Building Block for the Modular Synthesis of Mixed Diphosphine–NHC Heterometallic Complexes

Abstract

Fused in the same molecule! An N-heterocyclic carbene and a diphosphine are generated and used in the modular synthesis of a variety of target heterometallic complexes. The experimental approach involves formation of a unique 4,5-bis(diphenylphosphino)-1,3-dimethyl-imidazolium salt, simply by starting from 1-methylimidazole (see scheme; M(1) = Cr, Mn; M(2) = Au, Rh, Pd; LiHMDS = LiN(SiMe(3))(2)).

Advanced NMR Methods and DFT Calculations on the Regioselective Deprotonation and Functionalization of 1,1′‐Methylenebis(3‐methylimidazole‐2‐thione)

“…In addition, this knowledge was used to synthesize 4‐ and 4,5‐functionalized imidazol‐2‐ylidenes and mixed diphosphine–NHC heterometallic complexes …”

Mono‐ and Hetero‐Dinuclear Complexes of Janus‐Head NHC Ligands Possessing Backbone Phosphinoyl Groups: the Case of Soft and Hard Metal Centers

“…II, E = P(Mes)CHPh 2 ] employing the abnormal reaction of IMes with the phosphaalkene MesP=CPh 2 . [23] In 2013, we reported an anionic NHC containing a phosphanido-substituent (i.e. [22] Ruiz and co-workers exploited this concept to prepare a 4,5-diphosphinyl-substituted NHC of type III (E,EЈ = PPh 2 ) using imidazolium salt precursors.…”

“…[20] Shortly thereafter, Bertrand and coworkers reported a phosphine-substituted NHC of type II (E = PPh 2 ) that invoked an "abnormal NHC" (mesoionic carbene) [21] intermediate generated with base after temporarily blocking the C 2 position. [24] The development of NHCs containing soft P-based donors is of special interest due to their potential to function as precursors to novel homo-and hetero-dinuclear complexes of type IV and V. [20,23,25,26] We envisioned that imidazol-2-ylidenes bearing electronwithdrawing phosphinoyl group(s) in the backbone [e.g. [23] In 2013, we reported an anionic NHC containing a phosphanido-substituent (i.e.…”

On Route to C4/C5 P‐Bifunctional 1,3‐Thiazole‐Based Carbenes

“…The mono‐P‐functionalized NHCs were employed to access hetero‐ and homodimetallic complexes II (of Cu, Au, and Pd, Figure ) . In a somewhat related approach, Ruiz et al achieved the synthesis of 4,5‐diphosphanyl‐substituted imidazole‐2‐ylidenes III from air‐ and moisture‐stable imidazolium salts . In recent years, we have contributed to this field by establishing a new facile synthetic methodology, which starts from air‐ and moisture‐stable thiones instead of the NHCs, and obtained mono‐ and bis‐phosphanoyl‐substituted NHC complexes as well as mono‐ and heterodinuclear complexes IV .…”