Important Steric Effects Resulting from the Additional Substituent at Boron within Scorpionate Complexes Containing κ³‐NNH Coordination Modes

Abstract

The complexes [Ru(Tai) (5), mesityl (6) and 2-naphthyl (7)] have been prepared and fully characterised. Structural characterisation of complexes 4, 5 and 7 confirmed the expected κ 3 -NNH coordination mode of the azaindolyl-based ligands. In all complexes, the borohydride unit is located trans to the hydrido

Hydrogen atom storage upon Z-class borane ligand functions: an alternative approach to ligand cooperation

“…A number of investigations have been carried out focusing on providing a greater understanding of the B-HÁ Á Ámetal interactions in type I compounds. [35][36][37][38][39][40][41][42][43][44] Spicer has reviewed such interactions within complexes containing imidazole-2-thione supporting groups providing a categorisation of the interactions based on the metal-hydrogen distance. 45 Owen and co-workers has focused on these interactions in a series of scorpionate complexes containing 7-azaindolyl supporting units.…”

“…45 Owen and co-workers has focused on these interactions in a series of scorpionate complexes containing 7-azaindolyl supporting units. 36,38,[40][41][42][43] These nitrogen based scorpionate ligands, close analogues of Trofimenko's ubiquitous Tp ligands, were first introduced by Wang in 2005 46 and are currently the only nitrogen based scorpionate ligands to support metal-borane complexes. Within their investigations, they studied a number of related complexes, comparing their spectroscopic data and structural parameters.…”

“…6). 41,43 Table 1 provides selected NMR and IR spectroscopic data for these complexes. The difference between the two B-HÁ Á ÁRu interactions, in 8 and 9, is evident from the chemical shifts of the respective hydrogen atoms.…”

“…A survey of the literature reveals similar observations and shows that B-HÁ Á Ámetal interactions trans to p-donor ligands tend to provide interactions with much greater metal-hydride character when compared to those trans to strong s-donors. 41,43 In related investigations focusing on a different supporting group, Owen and co-workers attempted to prepare analogues of complex 9 (Scheme 3). 37 In this case, a hydride migration was observed and a deuterium labelling study revealed that the former borohydride hydrogen atom had been incorporated into the benzylidene fragment (this is an example of reaction type C, see below for details).…”

Boron, aluminium, gallium, indium and thallium

“…Dialkyl borahydrides have also been used to hydroborate disilynye complexes to from the boryl substituted disilyenes. 25 A number of metal complexes that support M-H-B s-bond agnostic interactions between the metal centre and boron hydrides [26][27][28][29][30] and hydroborates [31][32][33][34] have also been reported. The reaction of 1,3,7,9-tetramethyl-2,8diethyldipyrrin with BH 3 SMe 2 initially gives a dipyrrin-BH 3 adduct, which eliminates dihydrogen to form the dipyrrin-supported {BH 2 } borane.…”