Coordination Chemistry of Bis-Cyclic Alkyl(Amino) Carbene (cAAC)-Supported Di-Phosphorus (P ): An Efficient Route to Donor Base-Stabilized Elusive Di-Phosphorus-Monoxide(P O)-Gold Complex.

The stability and reactivity studies of heavier di-atomic group-15 congeners of alkynes, e. g., the di-phosphorus (P≡P) compounds have been the topic of huge interest because of their contrasting transient properties and lower stability compared to those of the stable molecular di-nitrogen (N≡N).

Isolation of (Aryl)-(Imino) Phosphide and (Aryl)-(Phosphaalkene) Amide Complexes of Alkali Metals from Carbene-Phosphinidenes under Reductive-Thermal Rearrangements.

Invited for the cover of this issue are Sudipta Roy and co-workers at the Indian Institute of Science Education and Research (IISER) Tirupati. The image depicts the rearrangement of cyclic alkyl(amino) carbene (cAAC)-supported chloro-phosphinidenes affording two ligands, of which one was used for the solid-state isolation of three cyclic alkyl(amino-boryl) phosphaalkenes and two coinage metal clusters. Read the full text of the article at 10.

Isolation of (Aryl)-(Imino) Phosphide and (Aryl)-(Phosphaalkene) Amide Complexes of Alkali Metals from Carbene-Phosphinidenes under Reductive-Thermal Rearrangements.

Two-electron reduction of cyclic alkyl(amino) carbene (cAAC)-supported chloro-phosphinidene cAAC=P-Cl (1) followed by unprecedented thermal rearrangements afforded the alkali metal complexes of (aryl)-(cyclic alkyl(imino)) phosphides 3 a-3 c, 4 a-4 b through migration of the 2,6-diisopropylphenyl (dipp) group from N to the P centre, and the (aryl)-(cyclic alkyl(phosphaalkene)) amide 5 through cleavage of the CMe -N bond followed by energetically favoured 5-exo-tet ring-closure in the presence of the alkali metals Cs (3 a-3 c), K (4 a, 4 b), and Li (5). Compound 3 a was found to be photoluminescent (PL), emitting bright orange light under a laboratory UV lamp of wavelength 365 nm with PL quantum yield (ϕ ) of 2.6 % (λ =600 nm), and an average lifetime (τ) of 4.

Isolation of Homo-/Mixed-Valence Ag , Ag , and Ag Clusters Stabilized by Cyclic Alkyl(amino) Carbene-Anchored Monoanionic Phosphorus Ligand.

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 Cl , Ag , and Ag cores [((cAAC)P) Ag Cl ](OTf) (1), [((cAAC)P) Ag ] (2), and [((cAAC)P) Ag ] (3) having three-/twofold symmetry, employing cyclic alkyl(amino) carbene (cAAC)-supported phosphinidenide (cAACP ) as the π-accepting stabilizing ligand. The average diameters of Ag NCs 1, and 2 are approximately 1.

Carbene-Anchored Boryl- and Stibanyl-Phosphaalkenes as Precursors for Bis-Phosphaalkenyl Dichlorogermane and Mixed-Valence Ag/Ag Phosphinidenide.

Cyclic alkyl(amino) carbene (cAAC)-anchored boryl- and stibanyl-phosphaalkenes with general formula cAAC = P-ER [E = B, R = (NPr) (); E = Sb, R = 2,4,6-triisopropylphenyl ()] have been synthesized and utilized as precursors for the bis-phosphaalkenyl dichlorogermane [(cAAC = P)GeCl] () and the first molecular example of a neutral polymeric mixed-valence Ag/Ag phosphinidenide complex [(cAACP)AgAgCl] (). 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 has been characterized by ESR spectroscopy.

Synthesis, oligomerization and catalytic studies of a redox-active Ni-cubane: a detailed mechanistic investigation.

A robust tetrameric nickel complex [Ni((O )L-Me)(s)] (3) (s = solvent) with cubane-like NiO core topology was isolated as a light greenish-orange crystalline solid in excellent yield. The mechanism of formation of 3 involving the two chloride-containing precursors [Ni((O )L-Me)(s)]·2MeOH (1) and [Ni((O)L-Me)((O )(OH)L-Me)Cl] (2) was studied by ESI mass spectrometry and confirmed by the solid state isolation and single-crystal X-ray diffraction. The challenging ligand fields containing mono/di-anionic ON donating atoms and/or chloride ions stabilized the pentacoordinate Ni(ii) ions in 1-2 upon controlling the experimental conditions.

Fluorescent organo-antimony compounds as precursors for syntheses of redox-active trimeric and dimeric alkali metal antimonides: an insight into electron transfer reduction processes.

(Tip)SbCl (1, Tip = 2,4,6-triisopropylphenyl) has been utilized as a precursor for the synthesis of the distibane (Tip)Sb (4) one-electron reduction using KC. The two-electron reduction of 1 and 4 afforded the novel trinuclear antimonide cluster [K((Tip)Sb)(THF)] (6). Changing the reducing agent from KC to a different alkali metal resulted in the solid-state isolation of corresponding stable dimeric alkali metal antimonides with the general formula [M((Tip)Sb)(THF)(tol)] (M = Li (14), Na (15), Cs (16)).

Solid-State Isolation of Cyclic Alkyl(Amino) Carbene (cAAC)-Supported Structurally Diverse Alkali Metal-Phosphinidenides.

Cyclic alkyl(amino) carbene (cAAC)-supported, structurally diverse alkali metal-phosphinidenides 2-5 of general formula ((cAAC)P-M) (THF) [2: M=K, n=2, x=4; 3: M=K, n=6, x=2; 4: M=K, n=4, x=4; 5: M=Na, n=3, x=1] have been synthesized by the reduction of cAAC-stabilized chloro-phosphinidene cAAC=P-Cl (1) utilizing metallic K or KC and Na-naphthalenide as reducing agents. Complexes 2-5 have been structurally characterized in solid state by NMR studies and single crystal X-ray diffraction. The proposed mechanism for the electron transfer process has been well-supported by cyclic voltammetry (CV) studies and Density Functional Theory (DFT) calculations.

Tridentate Nickel(II)-Catalyzed Chemodivergent C-H Functionalization and Cyclopropanation: Regioselective and Diastereoselective Access to Substituted Aromatic Heterocycles.

A Schiff-base nickel(II)-phosphene-catalyzed chemodivergent C-H functionalization and cyclopropanation of aromatic heterocycles is reported in moderate to excellent yields and very good regioselectivity and diastereoselectivity. The weak, noncovalent interaction between the phosphene ligand and Ni center facilitates the ligand dissociation, generating the electronically and coordinatively unsaturated active catalyst. The proposed mechanisms for the reported reactions are in good accord with the experimental results and theoretical calculations, providing a suitable model of stereocontrol for the cyclopropanation reaction.