On the Synthesis and Reduction of Trigonal Halido Bis(silylamido) Metalates of Chromium to Cobalt

Abstract

A series of halido bis(silylamido) metalates of chromium to cobalt is reported. Reaction of [NBu4]Br with linear metal silylamides ML2 (M=Mn−Co, L=−N(SiMe3)2, −N(Dipp)SiMe3; Dipp=2,6‐iPr−C6H3) leads to NBu4[M(Br)L2] whereas for chromium either intramolecular deprotonation (L=−N(SiMe3)2) or ligand exchange (L=−N(Dipp)SiMe3) is observed. Attempts for their reduction with KC8 showed in part the formation of linear metal(I) silylamide complexes but also degradation. In contrast, analogous compounds bearing a [K{18c6}]+ counter ion of cobalt and iron, obtained from reaction of anionic linear metal(I) complexes [M{N(SiMe3)2}2]− with allyl bromide – can be cleanly reduced. The adduct formation studies are also extended to benzyl potassium yielding [KM(Bn)L2] (M=Mn, Co) and subsequently the salt separated [K{18c6}][M(Bn)L2] using 18‐crown‐6 as sequestrating agent.

On the Synthesis of a T‐Shaped Imido Nickel Complex and Trigonal Amido Nickel Complexes

“…To possibly circumvent the direct reduction, we attempted to introduce the organic ligands via salt elimination reaction starting from the halogenido complex NBu 4 [NiBrL 2 ], [3] (Figure 3, right). Analogous to the known examples of iron and cobalt, [63] it was obtained by reacting [NiL 2 ] with NBu 4 Br in THF as a dark red crystalline material (34 % yield). X-ray diffraction analysis on suitable crystals revealed a distorted T-shaped geometry in solid state.…”

Intricate Road to Linear Anionic Nickel(I) Hexamethyldisilazanide [Ni(N(SiMe3)2)2]−

“…In recent years, the chemistry of monovalent 3d-metal hexamethyldisilazanides has been explored beyond tetrameric metal­(I) monosilylamides, namely, via the synthesis of the anionic linear complexes [M­(NR 2 ) 2 ] − of chromium to cobalt (Figure E). − These are obtained by reduction of the respective divalent precursors with KC 8 in the presence of 18-crown-6 or crypt.222. They are highly reactive, as expected from thefor these metalslow oxidation state in conjunction with the low-coordinate environment.…”

Impact of Spin-Phonon Coupling on Magnetic Relaxation of a Co(II) Single-Molecule Magnet

“…33 The well isolated ground spin-states of the rest three complexes also corroborate with the experimentally reported ground spinstates. 32,35,51 The energies of DFT optimized geometries for all the complexes in two possible spin states (HS and LS) are tabulated in Table 1. Following the structural optimization, single point calculations have been performed on the ground-spin state optimized geometry (Table S1 in SI).…”

“…Further, complex 2 and 4 have been identified by Andjaba et al and Weller et al respectively. 33,35 We have explicitly examined the spin-Hamiltonian parameters (ZFS parameters and g-values) for these four complexes. To ascertain the various relaxation pathways, including quantum tunneling of magnetization (QTM) in the ground state, 36 blocking barrier to magnetic relaxation have also been studied in detail.…”