Calix[4]pyrrolato Stannate(II): A Tetraamido Tin(II) Dianion and Strong Metal‐Centered σ‐Donor

Abstract

Anionic, metal‐centered nucleophiles are emerging compounds with unique reactivities. Here, we describe the isolation and full characterization of the first tetraamido tin(II) dianion, its behavior as ligand towards transition metals, and its reactivity as a tin‐centered nucleophile. Experimental values such as the Tolman electronic parameter (TEP) and computations attest tin‐located σ‐donor ability exceeding that of carbenes or electron‐rich phosphines. Against transition metals, the stannate(II) can act as η1‐ or η5‐type ligand. With aldehydes, it reacts by hydride substitution to give valuable acyl stannates. The reductive dehalogenation of iodobenzene indicates facile redox pathways mediated by halogen bond interaction. Calix[4]pyrrolato stannate(II) represents the first example of this macrocyclic ligand in low‐valent p‐block element chemistry.

Recent developments in calix[4]pyrrole (C4P)-based supramolecular functional systems

“…20). 128 To further explore 116, they also noticed its potential catalytic role in the dehydropolymerization process of phenylphosphine boranes (130) to high molecular weight polyphosphino boranes (131, Fig. 20).…”

“…21). 130 Interestingly, in case of iodobenzene, 132 plays a catalytic role in the reductive dehalogenation to benzene assisted by means of halogen-bonding interaction. On another occasion, they also reported the synthesis of a calix [4]pyrrolato Sb(III) ligand (141) and calix [4]pyrrolato Sb(V) ligand (142) and revealed the Lewis superacidity of 142 via the electromerism between the Sb(III) oxidation state of the redox-active ligand 141 and Sb(V) oxidation state of the redox-active ligand 142 (Fig.…”

Geometrically constrained square pyramidal phosphoranide

“…Geometrical constriction of p-block element-based compounds from their VSEPR geometries is emerging as a potent tool to modify their reactivity. 1 a–g Such alterations in geometry are achieved by employing ligands with suitable steric and electronic properties. 1 a–g This approach has recently drawn a lot of attention.…”

“… 1 a–g Such alterations in geometry are achieved by employing ligands with suitable steric and electronic properties. 1 a–g This approach has recently drawn a lot of attention. For example, Greb recently reported the synthesis and reactivity of a square pyramidal (SP) hydrosilicate, which was surprisingly inert in contrast to its trigonal bipyramidal (TBP) congeners, 2 abstraction of Cl − from the SP chlorosilicate gave a square planar silane.…”

Selective Oxidation of a Single Metal Site of Divalent Calix[4]pyrrolide Compounds [Ln2(N4Et8)(thf)4] (Ln = Sm or Eu), Giving Mixed Valent Lanthanoid(II/III) Complexes

“…meso -Octaethylcalix­[4]­pyrrole (H 4 N 4 Et 8 ) (Scheme ) has received much attention in recent years owing to its flexible coordination behavior and strong ability to stabilize many d -, p -, and f -block metal complexes, − including low-valent, mixed-valent, and bimetallic complexes. The use of low-valent and mixed-valent lanthanoid calix[4]­pyrrolide complexes is an attractive alternative in small-molecule activation because of the high reducing ability and high Lewis acidity of the lanthanoids.…”