Supramolecular self-assembly of heterobimetallic complexes: a new N,P-based, selective heteroditopic ligand

Abstract

Pyrimidine-hydrazone and phosphole architectures have been combined to create a new heteroditopic ligand capable of forming heterobimetallic Zn/Pd, Pb/Pd and Cu/Pd complexes in high yielding stepwise or one pot reactions. The catalytic activity of these complexes in Heck coupling and Miyaura borylation reactions was investigated.

The Self‐Assembly of AgI‐Containing Heterobimetallic Complexes with a Discriminatory N,P‐Based Heteroditopic Ligand

“…However, the Ag1–P1 and Ag2–P2 distances of 3.026(3) and 3.111(3) Å, respectively, are too long to be considered genuine Ag–P bonds. The meridional coordination of the octahedral Zn II ions in 2 to the pym‐, hyz‐ and py‐N donors and the hydroxymethyl arms of L1 is identical to that of the previously studied [Zn L1 (SO 3 CF 3 ) 2 ] complex . Each of the L1 molecules of 2 has a linear shape, due to the rotation of both coordination pockets to their cisoid‐cisoid conformations induced by the coordination of both metal ions by the pym‐N donors.…”

“…The analysis of the former two complexes by NMR spectroscopy showed that the Ag I ions are bound by the P and hyz‐N donors of the pym‐hyz‐phosphole coordination pocket, while the Zn II and Pb II ions are coordinated by all three N donors of the pym‐hyz‐py pocket and the hydroxymethyl arm (Scheme ). This binding results in the L1 molecules having a bent shape, with cisoid‐cisoid pym‐hyz‐py linkages and transoid‐cisoid pym‐hyz‐phosphole, as seen in the [Ag L1 ] 2 (SO 3 CF 3 ) 2 dimer ( 1 ) and the previously studied [Zn L1 (SO 3 CF 3 ) 2 ] complex . It is reasonable to assume that the binding of the Cu II and Ag I ions in [AgCu L1 (SO 3 CF 3 ) 3 ] is similar to these complexes, based on the studies of previous Cu II ‐containing pym‐hyz based complexes .…”

“…The difference in chemical shift between the two L1 molecules is particularly pronounced for the protons adjacent to the hyz‐ (H10 and H30, H18 and H48) and py‐N donors and the P donors (H22 and H52) that are coordinated to the Ag I ions. The coordination of the Ag I ions by P1 and P2 results in the deshielding of their resonances in the 31 P{ 1 H} NMR spectrum from –1.6 ppm for uncoordinated L1 to between 6.3 and 5.9 ppm. The signal from each P donor is split into two doublets due to coupling with the NMR active 109 Ag and 107 Ag isotopes of their coordinated Ag I ion.…”

“…Pb(SO 3 CF 3 ) 2 · H 2 O and Cu(SO 3 CF 3 ) 2 · 4H 2 O were produced through the treatment of 2PbCO 3 · Pb(OH) 2 or CuCO 3 · Cu(OH) 2 · H 2 O with aqueous triflic acid. Ligand L1 was synthesised according to its literature method …”

“…Due to the freewheeling nature of Ag I , the design of a heteroditopic ligand that can form predictable Ag I containing heterobimetallic complexes through self‐assembly is particularly challenging , . We recently described the synthesis of ligand L1 that contains discriminatory N‐based pyrimidine‐hydrazone‐pyridine (pym‐hyz‐py) and hybrid N,P‐based pym‐hyz‐phosphole coordination sites, and how this ligand reliably produced heterobimetallic complexes in one pot reactions with Zn II , Cu II and Pb II in combination with Pd II . Herein we report the structures formed through the reaction of Ag I triflate with L1 , both by itself and in combination with either Zn II , Pb II or Cu II triflate in one pot self‐assembly reactions (Scheme ).…”