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Unlike cations of metals such as sodium or calcium, oxidized silicon and germanium centers generally require strongly bound covalent ligands. We report the synthesis and characterization of a germanium(II) dication in the form of the salt (Ge.cryptand[2.2.2])(O3SCF3)2. The salt is isolated in 88% yield from the reaction of cryptand [2.2.2] and an N-heterocyclic carbene complex of GeCl(O3SCF3) as an air-sensitive, white solid. The crystal structure of the salt shows minimal interaction between the cryptand-encapsulated germanium(II) ion and the two -O3SCF3 counterions. These results suggest a widely expanded role of cryptands and related molecules in stabilizing nonmetallic cations.

A series of molecular gallium compounds were analyzed using X-ray photoelectron spectroscopy (XPS). Specifically, the Ga 2p3/2 and Ga 3d5/2 photoelectron binding energies and the Ga L3M45M45 Auger electron kinetic energies of compounds with gallium in a range of assigned oxidation numbers and with different stabilizing ligands were measured. Auger parameters were calculated and used to generate multiple chemical speciation (or Wagner) plots that were subsequently used to characterize the novel gallium-cryptand[2.2.2] complexes that possess ambiguous oxidation numbers for gallium. The results presented demonstrate the ability of widely accessible XPS instruments to experimentally determine the chemical state of gallium centers and, as a consequence, provide deeper insights into reactivity compared to assigned oxidation and valence numbers.

Ultrawideline 35Cl solid-state nuclear magnetic resonance (SSNMR) spectra of a series of 12 tin chlorides were recorded. The magnitude of the 35Cl quadrupolar coupling constant (C Q) was shown to consistently indicate the chemical state (oxidation number) of the bound Sn center. The chemical state of the Sn center was independently verified by tin Mössbauer spectroscopy. C Q(35Cl) values of >30 MHz correspond to Sn­(IV), while C Q(35Cl) readings of <30 MHz indicate that Sn­(II) is present. Tin-119 SSNMR experiments would seem to be the most direct and effective route to interrogating tin in these systems, yet we show that ambiguous results can emerge from this method, which may lead to an incorrect interpretation of the Sn oxidation number. The accumulated 35Cl NMR data are used as a guide to assign the Sn oxidation number in the mixed-valent metal complex Ph3PPdImSnCl2. The synthesis and crystal structure of the related Ph3PPtImSnCl2 are reported, and 195Pt and 35Cl SSNMR experiments were also used to investigate its Pt–Sn bonding. Plane-wave DFT calculations of 35Cl, 119Sn, and 195Pt NMR parameters are used to model and interpret experimental data, supported by computed 119Sn and 195Pt chemical shift tensor orientations. Given the ubiquity of directly bound Cl centers in organometallic and inorganic systems, there is tremendous potential for widespread usage of 35Cl SSNMR parameters to provide a reliable indication of the chemical state in metal chlorides.