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1. Photodriven Elimination of Chlorine From Germanium and Platinum in a Dinuclear Pt ^II →Ge ^IV Complex

   https://doi.org/10.1002/anie.202107485  

   Karimi, Mohammadjavad; Tabei, Elham S.; Fayad, Remi; Saber, Mohamed R.; Danilov, Evgeny O.; Jones, Cameron; Castellano, Felix N.; Gabbaï, François P. (September 2021, Angewandte Chemie International Edition)

   Abstract Searching for a connection between the two‐electron redox behavior of Group‐14 elements and their possible use as platforms for the photoreductive elimination of chlorine, we have studied the photochemistry of [(o‐(Ph₂P)C₆H₄)₂Ge^IVCl₂]Pt^IICl₂and [(o‐(Ph₂P)C₆H₄)₂ClGe^III]Pt^IIICl₃, two newly isolated isomeric complexes. These studies show that, in the presence of a chlorine trap, both isomers convert cleanly into the platinum germyl complex [(o‐(Ph₂P)C₆H₄)₂ClGe^III]Pt^ICl with quantum yields of 1.7 % and 3.2 % for the Ge^IV–Pt^IIand Ge^III–Pt^IIIisomers, respectively. Conversion of the Ge^IV–Pt^IIisomer into the platinum germyl complex is a rare example of a light‐induced transition‐metal/main‐group‐element bond‐forming process. Finally, transient‐absorption‐spectroscopy studies carried out on the Ge^III–Pt^IIIisomer point to a ligand arene–Cl^.charge‐transfer complex as an intermediate. 

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2. Solvothermal Synthesis of [Cr ₇ S ₈ (en) ₈ Cl ₂ ]Cl ₃  ⋅ 2H ₂ O with Magnetically Frustrated [Cr ₇ S ₈ ] ⁵⁺ Double‐Cubes**

   https://doi.org/10.1002/chem.202103761  

   Gamage, Eranga_H; Clark, Judith_K; Yazback, Maher; Cheng, Hai‐Ping; Shatruk, Michael; Kovnir, Kirill (December 2021, Chemistry – A European Journal)

   Abstract A novel transition metal chalcohalide [Cr₇S₈(en)₈Cl₂]Cl₃ ⋅ 2H₂O, with [Cr₇S₈]⁵⁺dicubane cationic clusters, has been synthesized by a low temperature solvothermal method, using dimethyl sulfoxide (DMSO) and ethylenediamine (en) solvents. Ethylenediamine ligand exhibits bi‐ and monodentate coordination modes; in the latter case ethylenediamine coordinates to Cr atoms of adjacent clusters, giving rise to a 2D polymeric structure. Although magnetic susceptibility shows no magnetic ordering down to 1.8 K, a highly negative Weiss constant,θ=−224(2) K, obtained from Curie‐Weiss fit of inverse susceptibility, suggests strong antiferromagnetic (AFM) interactions betweenS=3/2 Cr(III) centers. Due to the complexity of the system with (2S+1)⁷=16384 microstates from seven Cr³⁺centers, a simplified model with only two exchange constants was used for simulations. Density‐functional theory (DFT) calculations yielded the two exchange constants to beJ₁=−21.4 cm⁻¹andJ₂=−30.2 cm⁻¹, confirming competing AFM coupling between the shared Cr³⁺center and the peripheral Cr³⁺ions of the dicubane cluster. The best simulation of the experimental data was obtained withJ₁=−20.0 cm⁻¹andJ₂=−21.0 cm⁻¹, in agreement with the slightly stronger AFM exchange within the triangles of the peripheral Cr³⁺ions as compared to the AFM exchange between the central and peripheral Cr³⁺ions. This compound is proposed as a synthon towards magnetically frustrated systems assembled by linking dicubane transition metal‐chalcogenide clusters into polymeric networks. 

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3. Interactions Between [PdX ₄ ] ²⁻ (X=Cl, Br) Dianions in Presence of Counterions

   https://doi.org/10.1002/cphc.202400712  

   Trzęsowska, Natasza; Wysokiński, Rafał; Hajlaoui, Fadhel; Zouari, Nabil; Michalczyk, Mariusz; Scheiner, Steve; Zierkiewicz, Wiktor (December 2024, ChemPhysChem)

   Abstract The interaction between two square palladium (II) dianions PdX₄²⁻(X=Cl, Br) is evaluated by crystal study and analyzed by quantum chemical means. The arrangement within the crystal between each pair of PdX₄²⁻neighbors is suggestive of a Pd⋅⋅⋅X noncovalent bond, which is verified by a battery of computational protocols. While the potential between these two bare dianions is computed to be highly repulsive, the introduction of even just two counterions makes this interaction attractive, as does the presence of a constellation of point charges. It is concluded that there is indeed a stabilizing Pd⋅⋅⋅X bond, but it is incapable of overcoming the strong coulombic repulsive force between two dianions. While the QTAIM, NBO, and NCI tools can indicate the presence of a noncovalent bond, they are unable to distinguish an attractive from a repulsive interaction. 

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4. Observation of Transition‐Metal–Boron Triple Bonds in IrB ₂ O ⁻ and ReB ₂ O ⁻

   https://doi.org/10.1002/anie.202006652  

   Chen, Teng‐Teng; Cheung, Ling Fung; Chen, Wei‐Jia; Cavanagh, Joseph; Wang, Lai‐Sheng (June 2020, Angewandte Chemie International Edition)

   Abstract Multiple bonds between boron and transition metals are known in many borylene (:BR) complexes via metal d_π→BR back‐donation, despite the electron deficiency of boron. An electron‐precise metal–boron triple bond was first observed in BiB₂O⁻[Bi≡B−B≡O]⁻in which both boron atoms can be viewed as sp‐hybridized and the [B−BO]⁻fragment is isoelectronic to a carbyne (CR). To search for the first electron‐precise transition‐metal‐boron triple‐bond species, we have produced IrB₂O⁻and ReB₂O⁻and investigated them by photoelectron spectroscopy and quantum‐chemical calculations. The results allow to elucidate the structures and bonding in the two clusters. We find IrB₂O⁻has a closed‐shell bent structure (C_s,¹A′) with BO⁻coordinated to an Ir≡B unit, (⁻OB)Ir≡B, whereas ReB₂O⁻is linear (C_∞v,³Σ⁻) with an electron‐precise Re≡B triple bond, [Re≡B−B≡O]⁻. The results suggest the intriguing possibility of synthesizing compounds with electron‐precise M≡B triple bonds analogous to classical carbyne systems. 

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5. Electronic Structure of trans‐ [V ^II Cl ₂ (E(CH ₃ ) ₂ CH ₂ CH ₂ E(CH ₃ ) ₂ ) ₂ ], E=N, P

   https://doi.org/10.1002/ejic.202400395  

   Jafari, Mehrafshan_G; Zolnhofer, Eva_M; Fehn, Dominik; Heinemann, Frank_W; Opalade, Adedamola_A; Carroll, Patrick_J; Meyer, Karsten; Krzystek, J.; Ozarowski, Andrew; Mindiola, Daniel_J; et al (December 2024, European Journal of Inorganic Chemistry)

   Abstract Coordination complexes of general formulatrans‐[MX₂(R₂ECH₂CH₂ER₂)₂] (M^II=Ti, V, Cr, Mn; E=N or P; R=alkyl or aryl) are a cornerstone of coordination and organometallic chemistry. We investigate the electronic properties of two such complexes,trans‐[VCl₂(tmeda)₂] andtrans‐[VCl₂(dmpe)₂], which thus representtrans‐[MX₂(R₂ECH₂CH₂ER₂)₂] where M=V, X=Cl, R=Me and E=N (tmeda) and P (dmpe). These V^IIcomplexes haveS=3/2 ground states, as expected for octahedral d³. Their tetragonal distortion leads to zero‐field splitting (zfs) that is modest in magnitude (D≈0.3 cm⁻¹) relative to analogousS=1 Ti^IIand Cr^IIcomplexes. This parameter was determined from conventional EPR spectroscopy, but more effectively from high‐frequency and ‐field EPR (HFEPR) that determined the sign ofDas negative for the diamine complex, but positive for the diphosphine, which information had not been known for anytrans‐[VX₂(R₂ECH₂CH₂ER₂)₂] systems. The ligand‐field parameters oftrans‐[VCl₂(tmeda)₂] andtrans‐[VCl₂(dmpe)₂] are obtained using both classical theory andab initioquantum chemical theory. The results shed light not only on the electronic structure of V^IIin this environment, but also on differences between N and P donor ligands, a key comparison in coordination chemistry. 

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