Phospha-Scorpionate Complexes by Click Chemistry using Phenyl Azide and Ethynylphosphine Oxides

Abstract

The copper-catalyzed Click reaction of phenyl azide with ethynylphosphine oxides provides new P-substituted triazoles. With tris(ethynyl)phosphine oxide this route affords a versatile scorpionate ligand that coordinates to RhCl 3 as a tripodal N ligand. Upon reduction, the same ligand can act as a P donor to W(CO) 5 . Both coordination modes can be combined, giving access to a bimetallic Mo/W complex.

Tris(pyrazolyl)phosphine Oxide and Tris(triazolyl)phosphine Oxide Scorpion Ligands

“…[34][35][36] The OP(Tz Ph ) 3 ligand shows similar features as found in the two crystallographically characterized examples known so far, that is, the RhCl 3 [20] and PtMe 3 [BArF 24 ] [23] complexes of E Ph . Each copper atom is bound by a tridentate OP(Tz Ph ) 3 ligand, and a medial triazolyl nitrogen atom of the other ligand completes the coordination sphere.…”

“…Both ligand systems and some transition-metal complexes thereof are experimentally known, such as those shown in Figure 2. [9,20] The geometry of the lowest-energy form of the C Me2 ligand is nearly C 3 -symmetric. Evidently, introduction of the methyl groups causes a "ring flip" of two of the pyrazolyl rings of C. Introduction of the phenyl substituent on the triazole rings (E Ph ) has little effect on the geometry of E, which is hardly surprising as the phenyl substituents are positioned far from both the PO apex and the other rings.…”

“…The group of Peterson was the first to report on the tris(pyrazolyl)phosphine oxides (C) [10,11] and their coordination chemistry. [20] These neutral ligands E are readily accessible by a triple Click reaction, that is, a copper-catalyzed azide-alkyne cyclization, of an azide with tris-(alkynyl)phosphine oxide. [15][16][17][18] Recently, we showed that the related tris(triazolyl)phosphine oxides [OP(Tz) 3 (E)] coordinate to transition metals and reported the molecular structure of the RhCl 3 complex E Ph RhCl 3 (Figure 2, right).…”

“…[12,13] This chemistry was subsequently extended, [14][15][16][17][18][19] notably by Tolman and co-workers with chiral ligands based on chiral pyrazoles. [20] Bräse and co-workers subsequently reported a one-pot modification by treating alkynylmagnesium bromides with azides followed by addition of PCl 3 . [20] These neutral ligands E are readily accessible by a triple Click reaction, that is, a copper-catalyzed azide-alkyne cyclization, of an azide with tris-(alkynyl)phosphine oxide.…”

Synthesis of Click‐Chelator via Cu(I)‐Catalyzed Alkyne‐Azide Cycloaddition

“…As a stable aromatic heterocycle, the 1,2,3-triazole also contains two nitrogen atoms [N (2) and N(3)] with one pair of non-covalent electrons, indicating both of them can act as donors to coordinate with different metals. 3 Recent research revealed that N(3) atom of 1,2,3-triazole unit did take part in the coordination with metal, 4,5 which was confirmed by single crystal analysis. So 1,2,3-triazole-based ligands from CuAAC reaction have been applied in catalyst, radio-active labeling medicines, organometallics, [5][6][7][8][9][10][11][12] etc.…”