Tunable Binding of Dinitrogen to a Series of Heterobimetallic Hydride Complexes

Abstract

The reaction of [Ru(H)2(N2)2(PCy3)2] (1) with β-diketiminate stabilised hydrides of Al, Zn and Mg generates a series of new heterobimetallic complexes with either H2 or N2 ligated to the ruthenium centre. Changing the main group fragment of the M•Ru-N2 (M = Al, Zn, Mg) complexes can subtley alter the degree of binding, and therefore activation, of the diatomic ligand as evidenced by the v(NºN) absorptions in the infrared data. Experimental and computational data rationalise this tunable binding; decreasing the electronegativity of the main group from Al > Zn > Mg infers greater ionic character of these M•Ru-N2 complexes, this in turn results in greater destabilisation of the frontier molecular orbitals of ruthenium and therefore greater back-donation from Ru(4d) → π*(N2).

Heterometallic Mg−Ba Hydride Clusters in Hydrogenation Catalysis

“…[38][39][40][41] There is also a fast growing trend to disclose structures and reactivities of heterometallic s/d-block combinations. [42][43][44][45][46][47][48][49][50][51] With focus on main group chemistry, however, the blend of two group 2 metals seems to be largely unstudied. There is a rare example for Mg/Ca hydride complex (Figure 1, E) which was isolated from a mixture of [( DIPP BDI)Mg + ] [Al{OC(CF 3 ) 3 } 4 À ] and [( DIPP BDI)CaH] 2 .…”

Synthesis and reactivity of heterometallic complexes containing Mg- or Zn-metalloligands

“…Additionally, quantum theory of atoms-in-molecule (QTAIM) calculations showed the bond critical points (BCPs) between Rh and Mg, and Rh and H, but not Mg and H. From the experimental and theoretical data, complex 3 could be considered as a rhodiate complex in which a cationic magnesium fragment is stabilized by coordination with a rhodium anion. Afterwards, the strategy of adding Mg–H bonds to other transition metal hydrides was also used to construct a series of heterobimetallic TM–Mg complexes (TM = Zr, 9 Cu, 10 or Ru 11 ).…”

“…In this context, the Crimmin group reported a series of heterobimetallic Zn–TM complexes by the addition of one equivalent of zinc hydrides to the TM precursors (TM = Cu ( 24 ), Zr ( 25 ), Cr ( 26 , 28 ), Mn ( 27 ), Mo ( 29 ), W ( 30 ), Ru ( 31 ), Co ( 32 ) and Rh ( 33 , 34 )) (Scheme 9). 9,11,29–31 Moreover, an unsupported Zn–Mo bonded complex 35 was accessed via proteolytic cleavage of the Mo–H bond in CpMo(CO) 3 H with a terminal zinc hydride. 32…”

The partial dehydrogenation of aluminium dihydrides

“…Related s-silane complexes have been reported by Sabo-Etienne and coworkers, [23][24][25] while we recently disclosed a series of Ru-M (M ¼ Al, Zn, Mg) complexes with similar coordination geometries. 26 A 27,28 Monitoring the reaction between [Ru(H) 2 (N 2 ) 2 (PCy 3 ) 2 ] and 1b by 31 P{ 1 H} NMR spectroscopy revealed the formation of PCy 3 , d P ¼ 9.9 ppm. The structure of 3 was ultimately conrmed by X-ray crystallography (Fig.…”

“…The majority of previously reported Ru-Al complexes contain more than two metal centres and the Ru-Al distance in 3 is amongst the shortest reported. 26,[44][45][46][47] The examples of complexes with shorter Ru-Al distances result from reaction of low-valent [Cp*Al] 4 with Ru precursors. 46,47 5 contains a rhomboidal core of {Pd 2 Al 2 } with Pd and Al in alternate positions and hydride ligands bridging each edge of the square.…”