Magnesium, zinc, aluminium and gallium hydride complexes of the transition metals

Abstract

Here we survey and organise the state-of-the-art understanding of the TM–H–M linkage (M = Mg, Zn, Al, Ga). We discuss the structure and bonding in these complexes, their known reactivity, and their largely unrealised potential in catalysis.

Stereoisomerism of bis(σ‐Zincane) Complexes: Evidence for an Intramolecular Pathway

“…In the past few years, we, and others, have investigated the coordination of Al−H, Ga−H, Zn−H and Mg−H bonds to transition metals . Here, we report stereoisomerism in bis(σ‐zincane) complexes of the Group 6 carbonyls: fluxional heterotrimetallics.…”

“…[31,32] In the past few years, we, [33][34][35][36][37][38] and others, [39][40][41][42][43] have investigated the coordination of AlÀH, GaÀH, ZnÀHa nd MgÀHb onds to transition metals. [44,45] Here, we report stereoisomerism in bis(s-zincane) complexes of the Group 6c arbonyls:f luxional heterotrimetallics. Through acombined experimentala nd computational approach, we conclude that isomerisation occurs by an intramolecular mechanism that directly parallels classic examples.…”

Tunable Binding of Dinitrogen to a Series of Heterobimetallic Hydride Complexes

“…Two molecules are found within the asymmetric unit of Mg•Ru-N2, both are disordered with a second overlapping orientation and data are provided for the least disordered fragment.Bonding Analysis of M•Ru-N2:The metal---metal distances in M•Ru-N2 are all within the sum of the single bond radii as defined by Pauling21 and only the Ru---Zn distance is longer than the sum of the covalent radii defined by Pyykkö 22. We, and others, have considered normalised metal---metal bond distances and the formal shortness ratio as a crude metric to interrogate the nature of metal---metal bonds 11,[23][24][25]. The fsr of M•Ru-N2 determined using the Pauling radii are all ~1 and could be an indicator of a metal-metal bond (Al, 0.99; Zn, 1.00; Mg, 0.99).…”

Syntheses and Structures of Ruthenium Complexes Containing a Ru‐H‐Tl Three‐Center–Two‐Electron Bond

“…[1] Thecommonest transition-metal s-complexes are dihydrogen complexes L n M(h 2 -H 2 ). [2,3] Other reported transition-metal s-complexes with M À H À E3 c-2e bonding include those of the type L n M{h 2 -(H À EX n )} where Ei s aGroup 13 or 14 element [4] (E = B, [5] Al, [6] Ga, [7] C, [8,9] Si, [10,11] Ge, [12] Sn [13] ). Although of potential interest, s-complexes of the type L n M{h 2 -(HÀEX n )}, where Eisaperiod 6main-group element are still unknown.…”

“…Fortunately,b yl ayering n-hexane on top of aT HF solution containing am ixture of CpRuH(dppe) and TlPF 6 (in 1:2molar ratio) for one day,wehave successfully isolated ay ellow solid that was identified by X-ray diffraction as the h 2 -(HÀTl) complex [CpRu{h 2 -(HÀTl)}(dppe)]PF 6 (4)w ith aT HF molecule weakly coordinating to the thallium center in the solid state.ACD 2 Cl 2 solution of the solid displayed 1 HNMR signals of free THF,and hydride and 31 P{ 1 H} signals with chemical shifts similar to those observed in the in situ NMR spectrum for a1:1 mixture of CpRuH(dppe) and TlPF 6 . This observation suggests that the THF is likely not coordinated (or not strongly coordinated) to the Tl + center in CD 2 Cl 2 and that the species formed in the initial reaction of CpRuH(dppe) with TlPF 6 in CD 2 Cl 2 is the h 2 -(HÀTl) complex [CpRu{h 2 -(H À Tl)}(dppe)]PF 6 (4).…”