The Chatt reaction: conventional routes to homoleptic arenemetalates of d-block elements

Abstract

Homoleptic arenemetalates, including the depicted [K(18-crown-6)]2[Hf(C14H10)3], are often useful sources of “naked” metal anions and have been obtained for several transition metals via the Chatt reaction, named in honor of Joseph Chatt, a giant of chemistry.

Reduced Arene Complexes of Hafnium Supported by a Triamidoamine Ligand

“…Them ost upfield shifted multiplet at d = 2.63 for 2-anth also confirms that the anthracene ligand coordinates via its terminal and not by its central ring, because in this case the C 9,10 -H singlet signal should be most upfield shifted. The same coordination behavior in solution even at elevated temperature is shown by 1 HNMR spectra between 298 Kand 363 K, which do not show any significant alteration of the signal pattern of the anthracene ligand (Figure S14), except abroadening of some signals at higher temperature.…”

“…Monitoring the decomposition of 3 in [D 8 ]THF by 1 HNMR spectroscopy revealed that the diiminyl anthracene complex selectively loses one equivalent of benzonitrile to form the hafnium imido complex [K(thf)][Hf(anth)(XyÀ N 3 N)(PhCN)] (4)a fter migration of ap roton from C9 to C10 carbon atom of the anthracene ligand (Scheme 2). In fact, stirring ag reenish brown solution of 2-anth and 1equivalent of benzonitrile at room temperature for 48 hl ed to the selective formation of 4,which was isolated after work-up as an analytically pure,o range solid in 61 %y ield (see SI, Sec.2.8).…”

Calcium Hydride Reduction of Polycyclic Aromatic Hydrocarbons

“…Thes tepwise reduction of polycyclica romatic hydrocarbons (PAHs) such as naphthalene and anthracene has been studied since the mid-19 th century. [10] Unlike the 10p electron aromatization of COTt o[COT] 2À ,r eduction involves disruption of the aromatic system and population of the relevant antibonding p*L UMO.T he total free energy of the system may be estimated from the PA Hr eduction potentials which increase,t hat is become less negative,w ith the number of constituent C 6 carbocyles.With regard to group 2, the reaction of anthracene (E 0 = À1.98 and À2.44 Vvs. SCE) and magnesium is particularly well studied and, like the corresponding reactions with calcium, strontium and barium, can access the products of both single and two-electron reduction.…”

Heterogeneous Olefin Hydrogenation Enabled by a Highly‐Reduced Nickel(−II) Catalyst Precursor

“…Moreover,r ecent reports on asymmetric hydrogenations of dehy- droamino acids catalyzedb yN i(OAc) 2 and the chiral ligand (S)binapinea re noteworthy. [17] We previously investigated low-valent ferrate and cobaltate anions [K( [18]crown-6)(thf) 2 ][M(h 4 -anthracene) 2 ]( M = Fe, Co), and [K(thf) x ][Co(h 4 -cod) 2 ], first synthesized by the groupso f Ellis andJ onas, [18][19][20] as catalysts in the hydrogenation of olefins, ketones,a nd imines. [6] These "quasi-naked" anionic metal speciese xhibited high hydrogenation activities for mono/disubstituted C=Cb onds but fared poorly for sterically hindered tri/tetra-substitutedo lefins.Due to the lability of the arene and olefin ligands, both heterogeneous andh omogeneous mechanistic pathways are accessible, depending on the nature of the substrate.…”