A Tris(3‐pyridyl)stannane as a Building Block for Heterobimetallic Coordination Polymers and Supramolecular Cages

Abstract

The systematic assembly of supramolecular arrangements is a persistent challenge in modern coordination chemistry, especially where further aspects of complexity are concerned, as in the case of large molecular mixed‐metal arrangements. One targeted approach to such heterometallic complexes is to engineer metal‐based donor ligands of the correct geometry to build 3D arrangements upon coordination to other metals. This simple idea has, however, only rarely been applied to main group metal‐based ligand systems. Here, we show that the new, bench‐stable tris(3‐pyridyl)stannane ligand PhSn(3‐Py)3 (3‐Py=3‐pyridyl) provides simple access to a range of heterometallic SnIV/transition metal complexes, and that the presence of weakly coordinating counter anions can be used to build discrete molecular arrangements involving anion encapsulation. This work therefore provides a building strategy in this area, which parallels that of supramolecular transition metal chemistry.

Uncovering the Hidden Landscape of Tris(4‐pyridyl) Ligands: Topological Complexity Derived from the Bridgehead

“…As shown in Figure 5a, some of the PF 6 − anions are encapsulated within the cubane units and potentially act as templates. Similar templating using PF 6 − has recently been observed for discrete molecular cages formed from the PhSn(3‐py) 3 ligand, [19] and the influence of counter anions in supramolecular chemistry and crystal engineering is a well‐documented field [28]…”

“…The development of new classes of ligands is an important and ongoing challenge in modern chemistry, and a cornerstone in advances in catalysis, supramolecular assembly and biomimetic chemistry [1–7] . Of the many new classes of ligands that have been introduced, C 3 ‐symmetric tripodal ligands have emerged over the past few decades as one of the most important classes in catalysis [8] .…”

“…The development of new classes of ligands is an important and ongoing challenge in modern chemistry, and a cornerstone in advances in catalysis, supramolecular assembly and biomimetic chemistry. [1][2][3][4][5][6][7] Of the many new classes of ligands that have been introduced, C 3 -symmetric tripodal ligands have emerged over the past few decades as one of the most important classes in catalysis. [8] Amongst these, tris(pyrazolyl)borate (Tp À ) ligands (Figure 1a) [9] are recognised as one of the most versatile families, stemming from the ability to tune their electronic and steric properties by modifying the substitution of the heterocyclic rings.…”

“…[12][13][14][15][16] While the orientation of the donor-N atoms in tris(2-pyridyl) ligands leads to chelation of metal ions in the majority of complexes, changing the N-atom to the 3-or 4-positions introduces the prospect of forming supramolecular assemblies, as a result of bridging of the ligands between metal centers. Coordination studies in this area have, however, so far been limited to only a few E(3-py) 3 (E = P, [17] MeSi, [18] PhSn [19] ) and E(4py) 3 (E = CR, [20] P, [21] MeSi [22] ) ligands. Significantly, the coordination chemistry of tris(4-pyridyl) ligands containing the heavier more metallic p-block bridgeheads is a totally unexplored area.…”

Coordination chemistry of the bench-stable tris-2-pyridyl pnictogen ligands [E(6-Me-2-py)3] (E = As, AsO, Sb)

“…8 Our focus has been on the most metallic p-block elements (Figure 1, lower panel). [9][10][11][12][13] Coordination of metal-based ligands of this type to a range of main group and transition metal atoms provides a simple approach to the assembly of heterometallic complexes. In addition, introducing electropositive metal atoms also has a large effect on the charge distribution within the ligand frameworks and their reactivity.…”