New Experimental Insight into the Nature of Metal−Metal Bonds in Digallium Compounds: J Coupling between Quadrupolar Nuclei

Abstract

Multiple bonding between atoms is of ongoing fundamental and applied interest. Here, we report a multinuclear ((1) H, (13) C, and (71) Ga) solid-state magnetic resonance spectroscopic study of digallium compounds which have been proposed, albeit somewhat controversially, to contain single, double, and triple Ga-Ga bonds. Of particular relevance to the nature of these bonds, we have carried out two-dimensional (71) Ga J/D-resolved NMR experiments which provide a direct measurement of J((71) Ga,(71) Ga) spin-spin coupling constants across the gallium-gallium bonds. When placed in the context of clear-cut experimental data for analogous singly, doubly, and triply bonded carbon spin pairs or boron spin pairs, the (71) Ga NMR data clearly support the notion of a different bonding paradigm in the gallium systems. Our findings are consistent with an increasing role across the purported gallane-gallene-gallyne series for classical and/or slipped π-type bonding orbitals.

Near‐Infrared Light‐Responsive Cu‐Doped Cs2AgBiBr6

“…Another useful probe to the local bonding environment is provided by the presence and magnitude of spin-spin interaction (J-coupling). [24] The spin-spin interaction (J X-Bi = 1341 Hz, where X can be Br, Ag or Cu) in Cu-50 is significantly different from that in Cu-0 (J X-Bi = 2002 Hz, where X can be either Br or Ag), suggesting a different environment of Bi atoms caused by the replacement of Ag atoms by Cu + /Cu 2+ ions. Based on this understanding, we name the Cu-doped Cs 2 AgBiBr 6 samples as Cs 2 (Ag:Cu)BiBr 6 in the following parts.…”

NMR crystallography: structure and properties of materials from solid-state nuclear magnetic resonance observables

“…On the other hand, if the two B atoms are related by a crystallographic inversion centre, the doublet splitting is amplified by a factor of (2I + 3)(2I À 1)/4, which is equal to three for 11 B. Such experiments have been applied successfully to unambiguously provide information on the space-group symmetry of several compounds featuring quadrupolar spin pairs, including those with boron-boron, manganese-manganese, and gallium-gallium bonds ,b, 2015Kobera et al, 2016). One may establish independently and unambiguously whether the observed spectral splittings are equal to J or whether they are amplified by either (i) calibrating the method on a series of systems with known symmetries, (ii) quantum chemical calculations of the J-couplings, and/or (iii) performing analogous J-resolved NMR experiments on stationary (rather than spinning) powders and analyzing the sense of the anisotropic powder patterns produced (Perras & Bryce, 2014b).…”

Unexpected Crystallization Patterns of Zinc Boron Imidazolate Framework ZBIF‐1: NMR Crystallography of Integrated Metal–Organic Frameworks

“…Generally, the 1 H decoupling using mind boggling optimization (DUMBO)/MAS NMR technique is very helpful to assign structural descriptions of crystalline coordination compounds . However, in case of the ZBIF‐1 system, the 1D 1 H DUMBO technique was ineffective, as the resulting spectrum showed a very complicated spectral line that prevented straightforward interpretation.…”