Tris(pyrazolyl)phosphines with copper(i): from monomers to polymers

Abstract

The parent tris(pyrazolyl)phosphine and its 3,5-Me2, 3-Ph, and 3-t-Bu derivatives have been prepared by a simple procedure and show modest Lewis basicity of the phosphorus apex as was established by the magnitude of the (1)JP,Se coupling constant of the phosphine selenides. Because of the chelating properties of both the N- and P-sites, neutral phosphorus-centered scorpion ligands allow coordination modes that are unavailable to the abundantly used anionic tris(pyrazolyl)borate scorpionates as we established for Cu(I)-complexation. The substituted P-scorpion ligands only allow for N-coordination, as the P-apex is presumably less accessible. Two X-ray crystal structures were obtained for the Cu-complex of tris(3,5-dimethylpyrazolyl)-phosphine with acetonitrile and triphenylphosphine in the fourth coordination site. The parent P-scorpion ligand can chelate with both its pyrazolyl groups and its P-apex with the product depending on the ratio in which it is mixed with the Cu(I) complex. Reacting two equivalents of the ligand with [Cu(MeCN)4][PF6] resulted in a complex in which Cu is coordinated to the three pyrazolyl groups of one ligand and to the P-apex of the other ligand as confirmed by an X-ray crystal structure determination and a DFT computational analysis. Reacting the ligand and the Cu(I) complex in an equimolar ratio resulted in a remarkable one-dimensional P-scorpion coordination polymer for which a single crystal X-ray structure could be determined. A detailed analysis of the structural features is presented.

Architecture and synthesis of P,N-heterocyclic phosphine ligands

“…Application References pyridyl phosphines OLEDs [13] Heck coupling [14] metal organic frameworks [15] polymerization of lactides [16] alkene hydroxylation [17] addition reaction [18] ethylene oligomerization [19] synthesis of pyrazolines [20] triazolyl phosphines Suzuki cross coupling [21] asymmetric hydrogenation [22] luminescence [23] hydroformylation [24] pyrazolyl phosphines coordination polymers [25] Heck coupling [26] imidazolyl phosphines Suzuki coupling [27] hydroamination [28] OLEDs [29] ethylene oligomerization [30] amination [31] olefin metathesis [32] hydroformylation [33] pyrrolyl phosphines hydroformylation [34,35] ethylene polymerization [36] oxazolyl phosphines asymmetric cycloaddition [37] asymmetric hydrogenation [38] carbonylation of alkynes [39] allylic substitution [40] asymmetric addition [41] allylic amination [42,43] The presence of soft donor atoms such as phosphorus results in the formation of hemilabile ligands. These are multidentate ligands having hard P-donor and soft N-and/or O-donor atoms [44].…”

Versatile Coordination Modes of 2,6‐Bis(2‐(diphenylphosphanyl)‐1H‐imidazol‐1‐yl)pyridine in Cu(I) and Au(I) Complexes

“…[25] Some of the known 1D coordination polymers of copper(I) complexes supported by phosphine appendage with N-heterocyclic ligands are listed in Figure 1. In most of these complexes (I-V) [16,18,23,26,27] copper(I) ion show four coordinated tetrahedral arrangement. The reported compound VI is the first illustration of a rare 1D copper(I) coordination polymer stabilized by phosphine appended with N-heterocycles.…”

Tris(1‐methyl‐imidazol‐2‐yl)phosphane Complexes of Pnictogen, Tetrel, and Triel Cations

“…Tridentate L donors have promise as generic ligands for a wide array of metals and main‐group elements. For example, tris(2‐pyridyl)phosphine complexes of As 3+ and Sb 3+ , A have been reported, as well as tris(pyrazole)phosphine complexes of copper, magnesium, and phosphorus, B and a germanium analogue, C . Tris(1‐methyl‐imidazol‐2‐yl)phosphane, P(Im) 3 forms complexes with ruthenium, gold, rhenium and a variety of first‐row transition metals .…”

“…[21] Tridentate Ld onors have promise as genericl igandsf or a wide array of metals and main-group elements. For example, tris (2-pyridyl)phosphine complexes [12c] of As 3 + and Sb 3 + , A have been reported, as well as tris(pyrazole)phosphinec omplexes of copper, [22] magnesium, [23] and phosphorus, [24] B and a germanium analogue, C. [25] Tris(1-methyl-imidazol-2-yl)phos-phane, P(Im) 3 forms complexes with ruthenium, [26] gold, [27] rhenium and av ariety of first-row transition metals. [28,29] We now report the general application of P(Im) 3 with Ga 3 + ,I n 3 + ,G e 2 + , Sn 2 + ,P 3 + ,A s 3 + ,a nd Sb 3 + .T he triels accommodate two ligands in complexeso ft he generic formula [{P(Im) 3 } 2 M] 3 + ,w hereas complexes of the tetrels[ P(Im) 3 M] 2 + and pnictogens [P(Im) 3 M] 3 + form complexes with C 3v symmetric Janus head structures,w ith two energetically distinct apical lone pairs.…”