Main group pyridyl-based ligands; strategies to mixed metal complexes

Abstract

Tris-2-pyridyl ligands of the type [Y(2-py)(3)](n-) containing metallic or semi-metallic bridgehead atoms (Y) are a relatively new innovation in the area of main group coordination chemistry. This review highlights the major classes of ligands currently available, compares their coordination chemistry to their more well known non-metallic counterparts and explores the way in which they can be used to form heterometallic complexes in a targeted way.

Synthesis and coordination chemistry of 1,1,1-tris-(pyrid-2-yl)ethane

“…[2][3][4] Despite this long-standing chemistry, they continue to find use as facial protecting groups in organometallic chemistry, [5][6][7] catalysis, 8 transition metal photochemistry, 9 molecular magnetism [10][11][12][13][14] and other aspects of coordination chemistry. 15 A number of such ligands py 3 X (py = 2-pyridyl) have been prepared, with different bridgehead groups 'X' (Scheme 1).…”

Steric Effects on the Structures, Reactivity, and Coordination Chemistry of Tris(2‐pyridyl)aluminates

“…Of particular interest are tris(pyridyl)aluminates [RAl(2‐py′) 3 ] − , which are unusual in this area in that they are negatively charged instead of neutral ( B ; Figure 1). 3a As one of the only anionic members of the tris(pyridyl) family,5 the aluminates are particularly suitable for the coordination of metal cations. Indeed, aluminate ligands of this type have extensive coordination chemistry with a range of main‐group and transition‐metal ions 6.…”

How Changing the Bridgehead Can Affect the Properties of Tripodal Ligands

“…[1][2][3][4][5][6] Preeminent in this area are tris-pyrazolyl borates (Figure 1a), which have found countless applications as ancillary ligands over the last three decades in catalytic and biomimetic systems. [11][12][13][14][15][16][17][18][19][20][21][22][23][24] Despite the ongoing interest in expanding classical tripodal ligand sets,s uch as tris-pyrazolyl borate and tris-2pyridyl ligands,n os tudies have managed to decipher the actual effects of changing the size and electronic character of the bridgehead on structure and reactivity.The preparation of the neutral valence-isoelectronic tris-pryridyl ligands [E(6-Me-2-py) 3 ]( E= As,S b, Bi)h as allowed us to explore this issue for the first time on asingle class of main-group ligands of this type.Surprisingly,t here are no reports of the synthesis or coordination chemistry of tris-2-pyridyl ligands of Sb or Bi. [8][9][10] Our focus in this area has been the exploration of the reactivity and coordination chemistry of Group 13 and 14 tris-2-pyridyl ligands in which metallic or semi-metallic elements are present (like the aluminate shown in Figure 1c).…”

“…[8][9][10] Our focus in this area has been the exploration of the reactivity and coordination chemistry of Group 13 and 14 tris-2-pyridyl ligands in which metallic or semi-metallic elements are present (like the aluminate shown in Figure 1c). [11][12][13][14][15][16][17][18][19][20][21][22][23][24] Despite the ongoing interest in expanding classical tripodal ligand sets,s uch as tris-pyrazolyl borate and tris-2pyridyl ligands,n os tudies have managed to decipher the actual effects of changing the size and electronic character of the bridgehead on structure and reactivity.The preparation of the neutral valence-isoelectronic tris-pryridyl ligands [E(6-Me-2-py) 3 ]( E= As,S b, Bi)h as allowed us to explore this issue for the first time on asingle class of main-group ligands of this type.…”