Synthesis and Characterization of Primary Aluminum Parent Amides and Phosphides

Recent advances in atomic cluster synthesis: a perspective from chemical elements

Despite its potential significance, "cluster chemistry" remains a somewhat marginalized topic within the chemistry field. However, atomic clusters with their unusual and unique structures and properties represent a novel material group situated between molecules and nanoparticles or solid matter, judging from both scientific standpoints and historical backgrounds. Surveying an entire material group, including all substances that can be regarded as a cluster, is essential for establishing cluster chemistry as a more prominent chemistry field. This review aims to provide a comprehensive understanding by categorizing, summarizing, and reviewing clusters, focusing on their constituent elements in the periodic table. However, because numerous disparate synthetic processes have been individually developed to date, their straightforward and uniform classification is a challenging task. As such, comprehensively reviewing this field from a chemical composition viewpoint presents significant obstacles. It should be therefore noted that despite adopting a synthetic method-based classification in this review, the discussions presented herein could entail inaccuracies. Nevertheless, this unorthodox viewpoint unfolds a new scientific perspective which accentuates the common ground between different development processes by emphasizing the lack of a definitive border between their synthetic methods and material groups, thus opening new avenues for cementing cluster chemistry as an attractive chemistry field.

Molecular Main Group Metal Hydrides

This review serves to document advances in the synthesis, versatile bonding, and reactivity of molecular main group metal hydrides within Groups 1, 2, and 12-16. Particular attention will be given to the emerging use of said hydrides in the rapidly expanding field of Main Group element-mediated catalysis. While this review is comprehensive in nature, focus will be given to research appearing in the open literature since 2001.

Monomeric β-Diketiminato Group 13 Metal Dipnictogenide Complexes with Two Terminal EH2 Groups (E=P, As)

The pnictogenyl Group 13 compounds (Dipp2 Nacnac)M[E(SiMe3 )2 ]Cl and (Dipp2 Nacnac)M(EH2 )2 (Dipp2 Nacnac=HC[C(Me)N(Ar)]2 , Ar: Dipp=2,6-iPr2 C6 H3 ; M=Al, Ga, In; E=P, As) were successfully synthesized. The salt metathesis between (Dipp2 Nacnac)MCl2 and LiE(SiMe3 )2 only led to monosubstituted compounds (Dipp2 Nacnac)M[E(SiMe3 )2 ]Cl [E=P, M=Ga(1), In (2); E=As, M=Ga (3), In (4)], regardless of the stoichiometric ratios used. In contrast to the steric effect of the SiMe3 groups in 1-4, the reactions of the corresponding halides with LiPH2 ⋅DME (or KAsH2 ) facilely yielded the dipnictogenide compounds (Dipp2 Nacnac)M(EH2 )2 (E=P, M=Al (5), Ga (6), In (7); E=As, M=Al (8), Ga (9)), avoiding the use of flammable and toxic PH3 and AsH3 for their synthesis. The compounds 5-9 are the first examples of monomeric Group 13 diphosphanides and diarsanides in which the metal center is bound to two terminal PH2 and AsH2 groups, respectively. In contrast to the successful synthesis of the indium diphosphanide (Dipp2 Nacnac)In(PH2 )2 , the reaction of (Dipp2 Nacnac)InCl2 with KAsH2 led to an indium mirror due to the instability of the target product.

Stability and donor-acceptor bond in dinuclear organometallics CpM1-M2Cl3 (M1, M2 = B, Al, Ga, In; Cp = η 5-C5H5)

The geometries and stabilities of the dinuclear organometallics CpM₁-M₂Cl₃ (M₁, M₂ = B, Al, Ga, In; Cp = η ⁵-C₅H₅) have been investigated by density functional theory (DFT) at M06 L/6-311G(d, p) levels. The nature of the donor-acceptor M₁ → M₂ bond was also studied based on the atoms in molecules (AIM) theory, energy decomposition analysis (EDA) and natural bond orbital (NBO) analysis. The results show that the electronegativity of the M atom determines the stability and covalent character of the dinuclear organometallics CpM₁-M₂Cl₃. The compounds in which the M with larger electronegativity acts as the donor are more stable than in those in which it acts as the acceptor in the donor-acceptor bond, and the donor-acceptor bond has more covalent characteristics. The strength and polarity of the M₁ → M₂ donor-acceptor bond is determined by the periodicity of the M atom. When the period number of the M₁ atom is smaller than that of M₂, the strength of the M₁ → M₂ bond is larger than that of the M₂ → M₁ bond. For homonuclear dinuclear organometallics, the polarity of the M-M bond increases with increasing atomic number of the M atom. For heteronuclear complexes, the polarity of the M₁-M₂ bond for a given M₁ also increases in the sequence of M₂ = B, Al, Ga, and In. Graphic abstract Molecular graph and electron location function isosurfaces map of CpM 1 -M 2 Cl 3(small red spheres represent bond critical points).

Activation of Dihydrogen by Masked Doubly Bonded Aluminum Species

Activation of dihydrogen by masked dialumenes (Al=Al doubly bonded species) is reported. Reactions of barrelene-type dialumanes, which have the reactivity as masked equivalents of 1,2-diaryldialumenes ArAl=AlAr, with H2 afforded dihydroalumanes ArAlH2 at room temperature (Ar: bulky aryl groups). These dihydroalumanes form hydrogen-bridged dimers [ArHAl(μ-H)]2 in the crystalline state, while a monomer-dimer equilibrium was suggested in solution. The 1,2-diaryldialumenes generated from the barrelene-type dialumanes are the putative active species in the cleavage of H2 .