We report the use of 29 Si NMR spectroscopy and DFT calculations combined to benchmark the covalency in the chemical bonding of s-and f-block metal−silicon bonds. The complexes [M(Si t Bu 3 ) 2 (THF) 2 (THF) x ] (1-M: M = Mg, Ca, Yb, x = 0; M = Sm, Eu, x = 1) and [M(Si t Bu 2 Me) 2 (THF) 2 (THF) x ] (2-M: M = Mg, x = 0; M = Ca, Sm, Eu, Yb, x = 1) have been synthesized and characterized. DFT calculations and 29 Si NMR spectroscopic analyses of 1-M and 2-M (M = Mg, Ca, Yb, No, the last in silico due to experimental unavailability) together with known {Si(SiMe 3 ) 3 } − -, {Si(SiMe 2 H) 3 } − -, and {SiPh 3 } − -substituted analogues provide 20 representative examples spanning five silanide ligands and four divalent metals, revealing that the metal-bound 29 Si NMR isotropic chemical shifts, δ Si , span a wide (∼225 ppm) range when the metal is kept constant, and direct, linear correlations are found between δ Si and computed delocalization indices and quantum chemical topology interatomic exchange-correlation energies that are measures of bond covalency. The calculations reveal dominant s-and d-orbital character in the bonding of these silanide complexes, with no significant f-orbital contributions. The δ Si is determined, relatively, by paramagnetic shielding for a given metal when the silanide is varied but by the spin−orbit shielding term when the metal is varied for a given ligand. The calculations suggest a covalency ordering of No(II) > Yb(II) > Ca(II) ≈ Mg(II), challenging the traditional view of late actinide chemical bonding being equivalent to that of the late lanthanides.

We report the synthesis of the U(III) bis(cyclopentadienyl) hypersilanide complex [U(Cp′′)2{Si(SiMe¬3)3}] (Cp′′ = {C5H3(SiMe3)2-1,3}), together with isostructural lanthanide and group 4 M(III) homologues, in order to meaningfully compare metal-silicon bonding...

The last three decades have seen a significant increase in the number of reports of f-element carbon chemistry, whilst the f-element chemistry of silicon, germanium, tin, and lead remain underdeveloped...

Clusters of main group elements, such as phosphorus, arsenic, germanium, and tin - called Zintl clusters - have been known for more than a century. However, their application in main...

The novel series of heteroleptic Sm(iii) halide complexes provides the backdrop for a fluorescence-detected Lα1 X-ray absorption spectroscopic study.

The introduction of (N2)3–• radicals into multinuclear lanthanide molecular magnets raised hysteresis temperatures by stimulating strong exchange coupling between spin centers. Radical ligands with larger donor atoms could promote more efficient magnetic coupling between lanthanides to provide superior magnetic properties. Here, we show that heavy chalcogens (S, Se, Te) are primed to fulfill these criteria. The moderately reducing Sm­(II) complex, [Sm­(N††)2], where N†† is the bulky bis­(triisopropylsilyl)­amide ligand, can be oxidized (i) by diphenyldichalcogenides E2Ph2 (E = S, Se, Te) to form the mononuclear series [Sm­(N††)2(EPh)] (E = S, 1-S; Se, 1-Se, Te, 1-Te); (ii) S8 or Se8 to give dinuclear [{Sm­(N††)2}2(μ-η2:η2-E2)] (E = S, 2-S2 ; Se, 2-Se2 ); or (iii) with TePEt3 to yield [{Sm­(N††)2}­(μ-Te)] (3). These complexes have been characterized by single crystal X-ray diffraction, multinuclear NMR, FTIR, and electronic spectroscopy; the steric bulk of N†† dictates the formation of mononuclear complexes with chalcogenate ligands and dinuclear species with the chalcogenides. The Lα1 fluorescence-detected X-ray absorption spectra at the Sm L3-edge yielded resolved pre-edge and white-line peaks for 1-S and 2-E 2 , which served to calibrate our computational protocol in the successful reproduction of the spectral features. This method was employed to elucidate the ground state electronic structures for proposed oxidized and reduced variants of 2-E 2 . Reactivity is ligand-based, forming species with bridging superchalcogenide (E2)−• and subchalcogenide (E2)3–• radical ligands. The extraordinarily large exchange couplings provided by these dichalcogenide radicals reveal their suitability as potential successors to the benchmark (N2)3–• complexes in molecular magnets.

We report the synthesis and characterisation of isostructural thorium(IV)- and uranium(IV)-silanide actinide (An) complexes, providing an opportunity to directly compare Th-Si and U-Si chemical bonds. Quantum chemical calculations show significant...

We report the synthesis and characterisation of isostructural thorium(IV)- and uranium(IV)- silanide complexes, providing the first structurally authenticated Th-Si bond and a rare example of a molecular U-Si bond. These complexes therefore present the first opportunity to directly compare the chemical bonding of Th-Si and U-Si bonds. Quantum chemical calculations show significant and surprisingly similar 7s, 6d, and 5f orbital contributions from both actinide (An) elements in polarised covalent An-Si bonds