Extending N-heterocyclic carbene ligands into the third dimension: a new type of hybrid phosphazane/NHC system

Abstract

A new type of hybrid phosph(III)azane/NHC system is described in which a phosphazane P2N2 ring provides unique opportunities for modifying the electronic and steric character of these carbenes.

Structures, Electronics, and Reactivity of Strained Phosphazane Cages: A Combined Experimental and Computational Study

“…This trend is in excellent agreement with the parameters found in the experimental structures of the cations (range 1.79−1.83 Å; Table 1) and in the previously reported iridium(I) dimetallic complex G [1.756(3) and 1.760(3) Å; Scheme 1]. 7,17 In order to obtain a qualitative understanding of the underlying bonding in these species and the changes that accompany metal deprotonation and metal coordination, we analyzed the Kohn−Sham frontier molecular orbitals (FMOs). For a graphical representation of selected FMOs for M1−M3, see Figure 8 and the SI.…”

“…15 The reaction enthalpy for decoordination (ΔH = 42 kJ mol −1 ) was found to be similar to that previously reported for the analogous process in the related NHC cyclophosphazane iridium complex shown in Scheme 6. 7 The cage-opening reaction seen in the formation of the metal complexes 6a−6d (Scheme 3) can be regarded as occurring by chloride-induced ring opening and subsequent metal coordination. 16 This view is supported by the finding that the cationic cage 5a readily reacts with a stoichiometric amount of [nBu 4 …”

“…The deprotonation of compound 5e yielding an NHC and its coordination chemistry with selected late-transition-metal fragments has been reported by us previously. 7 In the current work, the focus is on the strained cationic cages themselves and their potential use as P donors for late-transition-metal complexes. 11 The coordination properties were assessed in reactions with iridium(I), rhodium(I), and palladium(II) precursors (giving the products 6a−6d; Scheme 3).…”

A modular approach to neutral P,N-ligands: synthesis and coordination chemistry

“…Driven by our recent efforts to provide easily accessible, modular ligand families [9–10], we have explored three different possibilities to expand the portfolio of P,N-ligands ( L1 – L3 , Fig. 1).…”

A Modular Approach to Inorganic Phosphazane Macrocycles

“…[11] One focus in this area has been to use the dichloro-phosph(III)azane dimer [ClP(m-N t Bu)] 2 (A), an established system in general inorganic synthesis, as a building block in the assembly of a range of PÀN bonded macrocycles of the type [{P(m-N t Bu)} 2 (m-Y)] n (Y = O or NH). [12][13][14][15][16][17][18][19][20] This approach involves the reactions of A with the NH-or Ofunctionalized dimers B or C (which are derived simply from A) (Scheme 1). [21,22] In the absence of a template, tetrameric macrocycles are produced for Y = O and NH (with n = 4).…”