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Free, publicly-accessible full text available October 26, 2024
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While the 1 : 1 reaction of 3 with an N-heterocyclic carbene ({(Me)CN(i-Pr)} 2 C:) in THF resulted in ligand-substituted product 4, the corresponding 1 : 2 reaction (in the presence of H 2 O) gives the first structurally characterized germanium tris(dithiolene)dianion 5 as the major product and the “naked” dithiolene radical 6˙ as a minor by-product. The structure and bonding of 4 and 5 were probed by experimental and theoretical methods. Our study suggests that carbene-mediated partial hydrolysis may represent a new method to access tris(dithiolene) complexes of main-group elements.more » « less
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Abstract Many binuclear nickel complexes have NiNi distances suggesting NiNi covalent bonds, including lantern‐type complexes with bridging bidentate ligands. This DFT study treats tetragonal, trigonal, and digonal lantern‐type complexes with the formamidinate, guanidinate, and formate ligands, besides some others. Formal bond orders (ranging from zero to two) are assigned to all the NiNi bonds on the basis of MO occupancy considerations. A VB‐based electron counting approach assigns plausible resonance structures to the dinickel cores. Model tetragonal complexes with the dimethylformamidinate and the dithioformate ligands have singlet ground states whose non‐covalently bonded NiNi distances are close to those in their experimentally known counterparts. Trigonal dinickel complexes are unknown, but are predicted to have quartet ground states with NiNi bonds of order 0.5. The model digonal complexes are predicted to have triplet ground states, but the predicted NiNi bond lengths are longer than those found in their experimentally known counterparts. This could owe to inadequate treatment of electron correlation by DFT in these short NiNi bonds with their multiconfigurational character. All the NiNi bond distances here are categorized into ranges according to the NiNi bond orders of 0, 0.5, 1, 1.5, and 2, no NiNi bonds of order higher than two being identified. The NiNi bonds of given order in these lantern‐type complexes are consistently shorter than the corresponding NiNi bonds in dinickel complexes having carbonyl ligands, attributable to the metalmetal bond lengthening effect of CO ligands.