N–H activation of hydrazines by a heterobimetallic Zr–Co complex: promotion of one-electron chemistry at Zr

Abstract

A tris(phosphino)amide-ligated Zr-Co heterobimetallic complex has been shown to activate N-H bonds of hydrazine derivatives via a proton-coupled electron transfer process. Such reactivity is highly unusual for an early metal such as Zr, but is promoted by the adjacent redox active Co atom.

Homo- and heteroleptic group 4 2-(diphenylphosphino)pyrrolide complexes: Synthesis, coordination chemistry and solution state dynamics

“…Thus, the extent of metal-metal bonding with first row transition metals is strongly dependent on the nature of the metal ions and metal coordination environment, rendering the bonding highly variable/tunable. Accordingly, Nagashima and Thomas have found that subtle variation of the electronic and steric properties of phosphinoamide ligand frameworks can drastically affect the structure and reactivity of mono-and bimetallic complexes [25][26][27][28][36][37][38][39][40][41][42][43][44][45]. Thus, we are interested in synthesizing trigonally symmetric heterobimetallic complexes of rigid, bifunctional hard/soft phosphinopyrrolide ligands to further the systematic study of metal-metal bonding and reactivity in P,N-bridged complexes.…”

“…In addition to the abovementioned ''Z-type'' bonding and reactivity, Thomas has observed Zr-Co multiple bonding that yields a diverse range of 1-and 2-electron processes that can result from direct or indirect reactivity of the metal-metal multiple bond: for example, CO 2 activation, hydrosilylation, E-H and E-E (E = N, O, S) bond activation [39][40][41][42][43][44][45]. Based on the plethora of chemistry available from a single class of early/late metal-metal multiple bonds, it is apparent that further investigation of these types of structures is warranted.…”

Effect of ligand modification on the reactivity of phosphinoamide-bridged heterobimetallic Zr/Co complexes

“…The Co-Zr Wiberg bond index (WBI) in complex 4 is calculated to be 0.91, while in complex 1 the Co-Zr WBI is 0.95. 12 Thus, we conclude that the Co center in 4 is markedly less electron rich than in complex 1 as a result of the less electron-donating nature of the [ i Pr 2 PNXyl] − ligand.…”

Synthesis and Characterization of Heterobimetallic Tantalum–Rhodium and Tantalum–Iridium Complexes Connected by a Tantalacyclopentadiene Fragment

“…Among them, heterobimetallic complexes containing early‐ and late‐transition metals (early‐late heterobimetallic complexes, ELHBs) have attracted special interest because they provide vastly different reaction sites that comprised of a hard Lewis acidic early‐transition metal and a soft Lewis basic late‐transition metal, respectively. [2] In addition, the unique nature of ELHBs is highlighted to the covalent bonding[3] and dative bonding[3c][4] character of the metal–metal interaction in ELHBs, and the metal–metal interaction has been widely applied for activating small molecules. [3i][4e – o][5] Such ELHBs involving a metal–metal interaction were categorized into two types of structures: one is a metal–metal bond without any bridging ligand, while the other is a ligand‐bridged metal–metal bonded structure.…”

“…In contrast, ligand‐supported early‐ and late‐heterobimetallic complexes are much more attractive because the metal–metal interaction or the proximity of the two metal centers is maintained, leading to unique reactivity. [3g – I][4k – o][8] Thus, we focused on the synthesis of ligand‐bridged heterobimetallic complexes having a metal–metal dative bond. Herein, we report the synthesis of a mononuclear tantalacyclopentadiene complex, (C 4 H 2 t Bu 2 )TaCl 3 ( 2 ), as a unique precursor for reacting with Rh and Ir cyclooctadiene complexes, giving the corresponding Ta–Rh and Ta–Ir heterobimetallic complexes.…”