Cyclic alkyl­(amino) carbene (cAAC)-anchored boryl- and stibanyl-phosphaalkenes with general formula cAAC = P–ER2 [E = B, R = (N i Pr2)2 (3a-c); E = Sb, R = 2,4,6-triisopropylphenyl (5a-b)] have been synthesized and utilized as precursors for the bis-phosphaalkenyl dichlorogermane [(cAAC = P)2GeCl2] (6) and the first molecular example of a neutral polymeric mixed-valence AgI/AgII phosphinidenide complex [(cAACP)2Ag4 IAgIICl4] n (7). All compounds have been characterized by single-crystal X-ray diffraction and further investigated by nuclear magnetic resonance (NMR), mass spectrometric analysis, and UV–vis/fluorescence measurements. The paramagnetic complex 7 has been characterized by ESR spectroscopy. Cyclic voltammetry studies of compounds 3/5 have suggested possible one-electron quasi-reversible reductions, indicating their redox noninnocent behavior in solution. Quantum chemical studies revealed the electron-sharing nature of the P–B and P–Sb σ bonds in compounds 3 and 5, and the polar CcAAC = P bonds in compounds 3, 5, and 6 prevailing their phosphaalkene structures over phosphinidenes.

Cyclic alkyl(amino) carbene‐anchored monoanionic phosphorus species have been introduced as the rising ligand to stabilize three unprecedented homo (AgI)‐ and mixed (Ag0/AgI)‐valence silver nanoclusters Ag29, Ag12 and Ag8 in the solid state with defined structures. The neutral Ag29 and Ag8 clusters showed electron paramagnetic resonance at room temperature, whereas the green‐emitting tri‐cationic Ag12 cluster is diamagnetic and NMR active. More information can be found in the Research Article by S. Roy and co‐workers (DOI: 10.1002/chem.202202324).

The elusive phosphinidene-chlorotetrylenes, [PGeCl] and [PSiCl] have been stabilized by the hetero-bileptic cyclic alkyl(amino) carbene (cAAC), N-heterocyclic carbene (NHC) ligands, and isolated in the solid state at room temperature as the first neutral monomeric species of this class with the general formulae (L)P-ECl(L') (E = Ge, 3 a-3 c; E = Si, 6; L = cAAC; L' = NHC). Compounds 3 a-3 c have been synthesized by the reaction of cAAC-supported potassium phosphinidenides [cAAC=PK(THF) x ] n (1 a-1 c) with the adduct NHC:!GeCl 2 (2). Similarly, compound 6 has been synthesized via reaction of 1 a with NHC:!SiCl 2 adduct (4). Compounds 3 a-3 c, and 6 have been structurally characterized by single-crystal X-ray diffraction, NMR spectroscopy and mass spectrometric analysis. DFT calculations revealed that the heteroatom P in 3 bears two lone pairs; the non-bonding pair with 67.8 % of sand 32 % of p character, whereas the other lone pair is involved in π backdonation to the C cAAC -N π* of cAAC. The Ge atom in 3 contains a lone pair with 80 % of s character, and slightly involved in the π backdonation to C NHC . EDA-NOCV analyses showed that two charged doublet fragments {(cAAC)(NHC)} + , and {PGeCl} À prefer to form one covalent electron-sharing σ bond, one dative σ bond, one dative π bond, and a charge polarized weak π bond. The covalent electron-sharing σ bond contributes to the major stabilization energy to the total orbital interaction energy of 3, enabling the first successful isolations of this class of compounds (3, 6) in the laboratory.

Silver clusters are attractive candidates for their promising optical properties, and biomedical activities. Herein, we report on the first syntheses and isolation of three homo-/mixed-valence silver nanoclusters (NCs) with Ag 12 Cl 3 , Ag 29 , and Ag 8 cores [((cAAC)P) 6 Ag 12 Cl 3 ](OTf) 3 (1), [((cAAC)P) 6 Ag 29 ] (2), and [((cAAC)P) 4 Ag 8 ] (3) having three-/ twofold symmetry, employing cyclic alkyl(amino) carbene (cAAC)-supported phosphinidenide (cAACP À ) as the π-accepting stabilizing ligand. The average diameters of Ag NCs 1, and 2 are approximately 1.6 to 2 nm. The redox non-innocent mono-atomic phosphorus anions (P À ) anchored with cAAC ligands are generated in situ by the reaction of AgOTf with a boryl-phosphaalkene (cAAC)PÀ B(N i Pr 2 ) 2 through cleavage of the PÀ B bond with the help of a triflate anion (OTf À ) as a [a

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