Ar igid naphthalenediamine framework has been used to prepare antimony hydrides that feature LUMO shapes and energies similar to those found in secondary boranes.B y exploiting this feature,w ei ntroduce the first examples of uncatalyzed hydrostibination reactions of robust CC, C=C, C = O, and N = Nb onds as new elementary hydrometalation reactions analogous to hydroboration. These results endorse the notion of ad iagonal relationship between the lightest p-block element and the heaviest Group 15 elements and may lead to the conception of novel reaction chemistry.

The use of pincer ligands to access non‐VSEPR geometries at main‐group centers is an emerging strategy for eliciting new stoichiometric and catalytic reactivity. As part of this effort, several different tridentate trianionic substituents have to date been employed at a range of different central elements, providing a patchwork dataset that precludes rigorous structure–function correlation. An analysis of periodic trends in structure (solid, solution, and computation), bonding, and reactivity based on systematic variation of the central element (P, As, Sb, or Bi) with retention of a single tridentate triamide substituent is reported herein. In this homologous series, the central element can adopt either a bent or planar geometry. The tendency to adopt planar geometries increases descending the group with the phosphorus triamide (1) and its arsenic congener (2) exhibiting bent conformations, and the antimony (3) and bismuth (4) analogues exhibiting a predominantly planar structure in solution. This trend has been rationalized using an energy decomposition analysis. A rare phase‐dependent dynamic covalent dimerization was observed for 3 and the associated thermodynamic parameters were established quantitatively. Planar geometries were found to engender lower LUMO energies and smaller band gaps than bent ones, resulting in different reactivity patterns. These results provide a benchmark dataset to guide further research in this rapidly emerging area.

Ligand design represents a central tenet of synthetic chemistry, wherein simple modification can lead to major differences in reactivity. Herein, we describe the preparation of two bis­(diphosphino)­nickel­(II) hydride complexes that contain eight pendant boranes in their secondary coordination sphere, [Ni­(H)­(P2BR 4)2]+ (R = Cy or Mes; Mes = 2,4,6-trimethylphenyl). Divergent reactivity of the cyclohexyl analogue toward the [NAD]+ model, 3-acetyl-N-benzylpyridinium bromide ([BNAcP]­Br), is underscored. While [Ni­(H)­(P2BCy 4)2]+ undergoes rapid hydride transfer, the related species [Ni­(H)­(dnppe)2]+ [dnppe = 1,2-bis­(di-n-propylphosphino)­ethane] and adduct [Ni­(H)­(P2BCy 4)2(DMAP)8]+ (DMAP = 4-N,N-dimethylaminopyridine) exhibit no such reactivity. This borane-appended nickel­(II) hydride distinguishes itself from its “all-alkyl” cousins and provides future opportunities for the design of [Ni­(H)­(diphosphine)2]+ reagents for hydride transfer.

Examples of unsymmetric diphosphines, especially those with customized secondary coordination spheres, are rare. Herein, we provide an approach towards a Lewis acid-containing analogue of the bulky diphosphine, 1,2-bis(di-tert-butylphosphino)ethane that contains a single boron moiety. The coordination chemistry of this ligand and its allyl precursor have been explored using nickel(0).

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