Viability of half‐sandwich complex of heavier group‐14 elements (SiPb) with neutral Be₃ring and its potential application asH₂storage material

Abstract

High level ab initio calculations were carried out to establish the half-sandwich structural behavior of heavier group-14 elements (Si Pb) with neutral Be 3 ring fragment and their molecular hydrogen adsorption capacity. The proposed complexes are found to be global minima on the potential energy surface after a rigorous systematic isomeric search. Quantum chemical investigation revealed that the complexes found possess high bond dissociation energy and also favorable thermodynamics of their formation. The complexes were also found to possess significant aromatic behavior. Among all the complexes, gravimetric density reaches more than the target level by US DOE in case of Be 3 Si and Be 3 Ge system which makes them potential target for molecular H 2 storage. Furthermore, the average adsorption energy, E ad for these two complexes ranges between physisorption and chemisorption process, thereby suggesting their reversible H 2 storage property.aromaticity, Be 3 ring fragment, group-14 elements, H 2 storage, half-sandwich complex | INTRODUCTIONThe origin of half-sandwich complex took place almost parallel to the discovery of ferrocene [1-4] when Fischer and Hafner carried out the synthesis of tetracarbonyl (cyclopentadienyl) vanadium complex, C 5 H 5 V(CO) 4 [5]. Since then, a number of half-sandwich complexes have been predicted and characterized so far [6][7][8][9][10][11][12][13][14][15][16]. Although the library of such complexes containing transition metals is rich, but half-sandwich complexes of main group elements are limited in the literature. Recently our group predicted the half-sandwich behavior of neutral Be 3 ring with some transition metals (Fe, Ru, Os, Zn, Cd, and Hg) [17]. The motive was to incorporate a transition metal two electron donor to neutral Be 3 ring to make the overall system aromatic. Upon complexation with the transition metals, it was found that aromaticity was induced in ring. Now will similar interaction happen with main group elements? To check this, we have chosen heavier group-14 elements (Si Pb) for this study (Scheme 1).The reason for choosing heavier group-14 elements is the presence of documented evidence of them participating in sandwich type complex formation. In 2018, Tholen et al. stabilized Ge (II) by incorporating it into borole dianion which resulted in the formation of a half sandwich complex [18]. Again, Guha et al. carried out high level ab initio calculations to predict a number of half-sandwich complexes between borole dianion and group-14 elements [19]. Further in 2020, Heitkemper and his group published the synthesis and characterization of the first neutral η5-borole complex of Si(II) [20]. The specificity of this complex is the nucleophilic reactivity which can be applied as a Si-centered donor ligand toward transition metals [20]. All of these studied complexes contain group-14 element in their +2 oxidation state as the anionic counterpart made the overall complex neutral.

Spodium bonding with noble gas atoms

“…83 The stability, reactivity, and bonding behaviour of noble gases have been the subject of ongoing scientific investigation by scientists and researchers. 16,84–106 Because of the presence of positive regions in Zn 3 , Cd 3 and Hg 3 rings, it will be interesting to explore the possibilities of non-covalent interactions between the noble gas atoms and the proposed ring (Zn 3 , Cd 3 and Hg 3 ) compounds. In this study, we attempted to analyze the bonding behavior between the proposed rings and the noble gas atoms (Ne–Xe).…”