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The 1 : 2 reaction of the imidazole‐based dithiolate (2) with GeCl₂ • dioxane in THF/TMEDA gives3, a TMEDA‐complexed dithiolene‐based germylene. Compound3is converted to monothiolate‐complexed (5) and N‐heterocyclic carbene‐complexed (7) germanium(II) dithiolene complexes via Lewis base ligand exchange. A bis‐dithiolene‐based germylene (8), involving a 3c–4e S‐Ge‐S bond, has also been synthesized through controlled hydrolysis of7. The bonding nature of3,5, and8was investigated by both experimental and theoretical methods.

Aluminyl anions are low‐valent, anionic, and carbenoid aluminum species commonly found stabilized with potassium cations from the reaction of Al‐halogen precursors and alkali compounds. These systems are very reactive toward the activation ofσ‐bonds and in reactions with electrophiles. Various research groups have detected that the potassium atoms play a stabilization role via electrostatic and cationinteractions with nearby (aromatic)‐carbocyclic rings from both the ligand and from the reaction with unsaturated substrates. Since stabilizing K⋯H bonds are witnessed in the activation of this class of molecules, we aim to unveil the role of these metals in the activation of the smaller and less polarizable H₂molecule, together with a comprehensive characterization of the reaction mechanism. In this work, the activation of H₂utilizing a NON‐xanthene‐Al dimer, [K{Al(NON)}]₂(D) and monomeric, [Al(NON)]⁻(M) complexes are studied using density functional theory and high‐level coupled‐cluster theory to reveal the potential role of K⁺atoms during the activation of this gas. Furthermore, we aim to reveal whetherDis more reactive thanM(or vice versa), or if complicity between the two monomer units exits within theDcomplex toward the activation of H₂. The results suggest that activation energies using the dimeric and monomeric complexes were found to be very close (around 33 kcal mol⁻¹). However, a partition of activation energies unveiled that the nature of the energy barriers for the monomeric and dimeric complexes are inherently different. The former is dominated by a more substantial distortion of the reactants (and increased interaction energies between them). Interestingly, during the oxidative addition, the distortion of the Al complex is minimal, while H₂distorts the most, usually over 0.77. Overall, it is found here that electrostatic and induction energies between the complexes and H₂are the main stabilizing components up to the respective transition states. The results suggest that the K⁺atoms act as stabilizers of the dimeric structure, and their cooperative role on the reaction mechanism may be negligible, acting as mere spectators in the activation of H₂. Cooperation between the two monomers inDis lacking, and therefore the subsequent activation of H₂is wholly disengaged.

Pnictinidenes are an increasingly relevant species in main group chemistry and generally exhibit proclivity for the triplet electronic ground state. However, the elusive singlet electronic states are often desired for chemical applications. We predict the singlet‐triplet energy differences (ΔE_ST=E_Singlet−E_Triplet) of simple group 15 and 16 substituted pnictinidenes (Pn−R; Pn=P, As, Sb, or Bi) with highly reliable focal‐point analyses targeting the CCSDTQ/CBS level of theory. The only cases we predict to have favorable singlet states are P−PH₂(−3.2 kcal mol⁻¹) and P−NH₂(−0.2 kcal mol⁻¹). ΔE_STtrends are discussed in light of the geometric predictions as well as qualitative natural bond order analysis to elucidate some of the important electronic structure features. Our work provides a rigorous benchmark for the ΔE_STof fundamental Pn−R moieties and provides a firm foundation for the continued study of heavier pnictinidenes.

Sulfur dioxide and hypohalous acids (HOX, X=F, Cl, Br, I) are ubiquitous molecules in the atmosphere that are central to important processes like seasonal ozone depletion, acid rain, and cloud nucleation. We present the first theoretical examination of the HOX⋯SO₂binary complexes and the associated trends due to halogen substitution. Reliable geometries were optimized at the CCSD(T)/aug‐cc‐pV(T+d)Z level of theory for HOF and HOCl complexes. The HOBr and HOI complexes were optimized at the CCSD(T)/aug‐cc‐pV(D+d)Z level of theory with the exception of the Br and I atoms which were modeled with an aug‐cc‐pwCVDZ‐PP pseudopotential. 27 HOX⋯SO₂complexes were characterized and the focal point method was employed to produce CCSDT(Q)/CBS interaction energies. Natural Bond Orbital analysis and Symmetry Adapted Perturbation Theory were used to classify the nature of each principle interaction. The interaction energies of all HOX⋯SO₂complexes in this study ranged from 1.35 to 3.81 kcal mol⁻¹. The single‐interaction hydrogen bonded complexes spanned a range of 2.62 to 3.07 kcal mol⁻¹, while the single‐interaction halogen bonded complexes were far more sensitive to halogen substitution ranging from 1.35 to 3.06 kcal mol⁻¹, indicating that the two types of interactions are extremely competitive for heavier halogens. Our results provide insight into the interactions between HOX and SO₂which may guide further research of related systems.

Binuclear alkyne manganese carbonyls of the type (RC≡CR')Mn₂(CO)_n(R and R'=methyl or dimethylamino;n=8, 7, 6) and their isomers related to the experimentally known (MeC₂NEt₂)Mn₂(CO)_n(n=8, 7) structures have been investigated by density functional theory. The alkyne ligand remains intact in the only low energy (Me₂N)₂C₂Mn₂(CO)₈isomer, which has a central Mn₂C₂tetrahedrane unit and is otherwise analogous to the well‐known (alkyne)Co₂(CO)₆derivatives except for one more CO group per metal atom. The low‐energy structures of the unsaturated (Me₂N)₂C₂Mn₂(CO)_n(n=7, 6) systems include isomers in which the nitrogen atom of one of the dimethylamino groups as well as the C≡C triple bond of the alkyne is coordinated to the central Mn₂unit. In other low‐energy (Me₂N)₂C₂Mn₂(CO)_n(n=7, 6) isomers the alkyne C≡C triple bond has broken completely to form two separate bridging dimethylaminocarbyne Me₂NC ligands analogous to the experimentally known iron carbonyl complex (Et₂NC)₂Fe₂(CO)₆. The (alkyne)Mn₂(CO)_n(n=8, 7, 6) systems of the alkynes MeC≡CMe and Me₂NC≡CMe with methyl substituents have significantly more complicated potential surfaces. In these systems the lowest energy isomers have bridging ligands derived from the alkyne in which one or two hydrogen atoms have migrated from a methyl group to one or both of the alkyne carbon atoms. These bridging ligands include allene, manganallyl, and vinylcarbene ligands, the first two of which have been realized experimentally in research by Adams and coworkers. Theoretical studies suggest that the mechanism for the conversion of the simple alkyne octacarbonyl (MeC₂NMe₂)Mn₂(CO)₈to the dimethylaminomanganaallyl complex Mn₂(CO)₇[μ‐η⁴‐C₃H₃Me₂] involves decarbonylation to the heptacarbonyl and the hexacarbonyl complexes. Subsequent hydrogen migrations then occur through intermediates with C−H−Mn agostic interactions to give the final product. Eight transition states for this mechanistic sequence have been identified with activation energies of ∼20 kcal/mol for the first hydrogen migration and ∼14 kcal/mol for the second hydrogen migration.