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  1. Free, publicly-accessible full text available October 26, 2024
  2. 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. 
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  4. Abstract

    Many binuclear nickel complexes have NiNi distances suggesting NiNi 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 NiNi 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 NiNi distances are close to those in their experimentally known counterparts. Trigonal dinickel complexes are unknown, but are predicted to have quartet ground states with NiNi bonds of order 0.5. The model digonal complexes are predicted to have triplet ground states, but the predicted NiNi 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 NiNi bonds with their multiconfigurational character. All the NiNi bond distances here are categorized into ranges according to the NiNi bond orders of 0, 0.5, 1, 1.5, and 2, no NiNi bonds of order higher than two being identified. The NiNi bonds of given order in these lantern‐type complexes are consistently shorter than the corresponding NiNi bonds in dinickel complexes having carbonyl ligands, attributable to the metalmetal bond lengthening effect of CO ligands.

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