Easy access to strongly fluorescent higher homologues of BODIPY.

We present the easy and high yield synthesis of several group 13 MesDPM compounds (Al-In) with alkyl substituents at the metal atom. All these compounds were fully characterized using techniques including X-ray diffraction analysis and photoluminescence measurements. It shows that for aluminium and gallium pronounced green fluorescence is observed, which is absent for indium. DFT calculations confirm that the first electronic transition corresponds to a ligand-based π-π* transition.

Formation and Reactivity of heavy Group 14-15 bonds.

A series of low-valent Group 14-15 compounds were obtained starting from [(Dipp2 NacNac)MCl] (M=Ge-Pb) (I-III) (Dipp2 NacNac=HC{C(Me)N(Dipp)}2 ) and M'E(SiMe3 )2 (M'=Li, E=As; M'=K, E=Sb, Bi) (IV-VI). In the course of this investigations we were able to fully characterize all permutations except Pb-Bi for compounds of the composition [(Dipp2 NacNac)ME(SiMe3 )2 ] (1E : M=Ge, 2E : M=Sn, 3E : M=Pb). Thus, we report the first low valent tetrelene with Sn-Bi bond. All isolated compounds, were examined by NMR spectroscopy, IR spectroscopy and except compound 1As by X-ray structure analysis. Moreover, were examined UV-Vis spectroscopy and investigated the reactivity of these compounds towards different substrates in more detail. Starting with the compound [(Dipp2 NacNac)SnAs(SiMe3 )2 ] (2As ), the reaction with red selenium yields [(Dipp2 NacNac)Sn-Se-As(SiMe3 )2 ] (4) which exhibits a Sn-Se-As chain.

Bismuth Cations: Fluoride Ion Abstraction, Isocyanide Coordination, and Impact of Steric Bulk on Lewis Acidity.

Invited for the cover of this issue are the groups of Carsten von Hänisch and Crispin Lichtenberg at the Philipps University of Marburg. The image depicts a bismuth kraken, eagerly grabbing Lewis basic substrates, thereby solving scientific puzzles about bismuth-based Lewis acidity. Read the full text of the article at 10.1002/chem.202204012.

Bismuth Cations: Fluoride Ion Abstraction, Isocyanide Coordination, and Impact of Steric Bulk on Lewis Acidity.

The molecular compound [BiDipp2 (SbF6 )], containing the bulky, donor-free bismuth cation [BiDipp2 ]+ has been synthesized and fully characterized (Dipp=2,6-iPr2 -C6 H3 ). Using its methyl analog [BiMe2 (SbF6 )] as a second reference point, the impact of steric bulk on bismuth-based Lewis acidity was investigated in a combined experimental (Gutmann-Beckett and modified Gutmann-Beckett methods) and theoretical approach (DFT calculations). Reactivity studies of the bismuth cations towards [PF6 ]- and neutral Lewis bases such as isocyanides C≡NR' revealed facile fluoride ion abstraction and straightforward Lewis pair formation, respectively. The first examples of compounds featuring bismuth-bound isocyanides have been isolated and fully characterized.

Heavy Chains: Synthesis, Reactivity and Decomposition of Interpnictogen Chains with Terminal Diaryl Bismuth Fragments.

Invited for the cover of this issue is the group of Carsten von Hänisch at the Philipps-University Marburg. The image depicts a bismuth crystal, a chain formed from it and the molecular structures of different chain molecules with diaryl-bismuth groups. Read the full text of the article at 10.1002/chem.202202932.

Heavy Chains: Synthesis, Reactivity and Decomposition of Interpnictogen Chains with Terminal Diaryl Bismuth Fragments.

In this work, we report the preparation of multiple interpnictogen chain compounds with three consecutive pnictogen atoms and terminal Ar2 Bi fragments (Ar=Ph, Mes). Symmetrical compounds of the form Ar2 Bi-E(tBu)-Bi2 Ar (1: Ar=Ph, E=P; 2: Ar=Ph, Mes, E=As) as well as ternary interpnictogen compounds of the form Ar2 Bi-E1 (tBu)-E2 tBu2 (Ar=Ph, Mes; 4: E1 =P, E2 =As; 5: E1 =P, E2 =Sb; 6: E1 =As, E2 =P) were prepared. The decomposition in solution at room temperature and under the influence of light was studied for compounds 1-6. The reactivity of 1Ph and 2Ph with the small N-heterocyclic carbene 1,3,4,5-tetramethylimidazol-2-ylidene (Me2 IMe) was also studied. In the case of 1Ph , the formation and consecutive decomposition of Me2 IMe=PtBu (8) was observed in solution. Hence, it was shown that 1Ph can react as a "masked phosphinidene". In the case of 2Ph , no reaction with Me2 IMe was observed. All isolated compounds were analysed by NMR and IR spectroscopy, mass spectrometry, elemental analysis and single-crystal X-ray diffraction.

Synthesis and Application of Alkali Metal Antimonide-A New Approach to Antimony Chemistry.

Alkali metal dihydrogen-antimonides [M(L)x SbH2 ], short: alkali metal antimonides (M=Li, Na, K, Rb, Cs; 1: L=pmdta; 2: L=crown-ether), were prepared from stibine and n-Butyllithium, M(hmds) (hmds=hexamethyldisilazane) or MOtBu, respectively. We developed a generally applicable synthesis route for these compounds and the obtained compounds were examined on their stability depending on the alkali metal and stabilizing additives used, whereby the use of appropriate crown-ethers allowed their isolation and characterization at room temperature. Moreover, the 1,4-dioxane adduct [Na(dioxane)x SbH2 ] was the appropriate starting compound for the synthesis of the first primary silylstibane (Me3 Si)3 SiSbH2 (3) which was characterized by NMR and IR spectroscopy. Reaction of 3 with (Dipp2 NacNac)Ga (Dipp2 NacNac=HC{C(Me)N(Dipp)}2 ; Dipp=2,6-iPr2 C6 H3 ) resulted in the formation of (Dipp2 NacNac)GaH(SbHSi(SiMe3 )3 ) (4) which was furthermore characterized by single crystal x-ray diffraction.

Binary interpnictogen compounds bearing diaryl bismuth fragments bound to all lighter pnictogens.

Multiple interpnictogen compounds with covalent single bonds between a diarylbismuth fragment and all lighter pnictogens were prepared from the corresponding diarylhalido bismuthanes. The aminobismuthanes Ph2BiNMe2 (1) and Mes2BiNMe2 (2) (Mes = 2,4,6-trimethylphenyl-) have been obtained via a salt metathesis reaction and compound 2 was successfully reacted with tBuNH2 in a condensation reaction to yield Mes2BiNHtBu (3). The bismuthanyl phosphanes Ar2BiPtBu2 (Ar = Ph: 4 and Ar = Mes: 5) and arsanes Ar2BiAstBu2 (Ar = Ph: 8 and Ar = Mes: 9) were also obtained via salt metathesis. Through a trimethylsilyl halide abstraction reaction of the diaryl halido bismuthanes and EtBu(SiMe3)2 (E = P and As), the bismuthanyl phosphanes Ar2BiPtBu(SiMe3) (Ar = Ph: 6; Ar = Mes: 7) and the arsanes Ar2BiAstBu(SiMe3) (Ar = Ph: 10; Ar = Mes: 11) have been prepared. Bismuthanyl stibanes were accessed via a condensation reaction of Mes2SbH with 1 or 2, respectively. The compound Ph2BiSbMes2 (12), which has different substituents at the bismuth and antimony atoms, was isolated and fully characterised. In contrast, the isolation of Mes2BiSbMes2 (13) was not possible due to a dynamic equilibrium with Mes4Bi2 and Mes4Sb2 which was investigated via low-temperature 1H-NMR spectroscopy in solution. The isolated compounds with a single bond between bismuth and the heavy pnictogens arsenic and antimony are rare examples of their kind. All isolated compounds (1-12) were characterised by NMR and IR spectroscopy, mass spectrometry, elemental analysis and single crystal X-ray diffraction.

Isolable Diaminophosphide Boranes.

Metalation of secondary diaminophosphine boranes by alkali metal amides provides a robust and selective access route to a range of metal diaminophosphide boranes M[(R2 N)2 P(BH3 )] (M=Li, Na, K; R=alkyl, aryl) with acyclic or heterocyclic molecular backbones, whereas reduction of a chlorodiaminophosphine borane gave less satisfactory results. The metalated species were characterized in situ by NMR spectroscopy and in two cases isolated as crystalline solids. Single-crystal XRD studies revealed the presence of salt-like structures with strongly interacting ions. Synthetic applications of K[(R2 N)2 P(BH3 )] were studied in reactions with a 1,2-dichlorodisilane and CS2 , which afforded either mono- or difunctional phosphine boranes with a rare combination of electronegative amino and electropositive functional disilanyl groups on phosphorus, or a phosphinodithioformate. Spectroscopic studies gave a first hint that removal of the borane fragment may be feasible.