Donor-free 9-aluminafluorenes: molecular structures and reactivity.

Aluminum-doped polycyclic aromatic hydrocarbons (PAHs) are underexplored despite the broad applications of boron-containing PAHs in areas such as catalysis and optoelectronics. We disclose the donor-free, sterically unprotected 9-methyl-9-aluminafluorene (Me-AlFlu; 2), synthesized by heating a 9,9-dimethyl-9-stannafluorene and AlMe in hexanes. The compound is a dimer, (2), with -positioned Al substituents in the solid state.

Adjusting the Number of Functional Groups in Vicinal Bis(trichlorosilylated) Benzenes.

Organo(chloro)silanes are essential chemicals, but the synthesis of compounds of the formula RSiCl with defined values of n is usually laborious. Herein, we first disclose that a [4+2]-cycloaddition between readily available ClSiC≡CSiCl and selected dienes provides facile access to vicinal bis(trichlorosilylated) benzenes and bicyclo[2.2.

Borylation and rearrangement reactions of azasilaanthracenes to afford B,N-doped nanographenes.

An air-stable B,N-containing dibenzobisanthene (8) was prepared in 29% yield by heating a 1,3,5-tri(azasilaanthryl)benzene (5) with BBr (180 °C). Under these conditions, the reaction does not stop after threefold SiMe/BBr exchange but proceeds further two rearrangement and two intramolecular C-H borylation steps. Some mechanistic details were unveiled by using smaller model systems and applying lower reaction temperatures.

Tetramerization of BEB-Doped Phenalenyls to Obtain (BE)-[16]Annulenes (E = N, O).

Two (BE)-[16]annulenes were prepared and fully characterized by experimental and quantum-chemical means (, E = N; , E = O). The 1,8-naphthalenediyl-bridged diborane(6) served as their common starting material, which was treated with [Al(NH)]Cl to form (91% yield) or with 1,8-naphthalenediboronic acid anhydride to form (93% yield). As a result, the heteroannulenes and are supported by four aromatic "clamps" and may also be viewed as NH- or O-bridged cyclic tetramers of BNB- or BOB-doped phenalenyls.

Green-Emitting Extended B,N-Doped Polycyclic Aromatic Hydrocarbon with Multiple Resonance Structure.

An air-stable B,N-PAH (; nine annulated six-membered rings) was synthesized from 1-X-2,6-di(azasilaanthryl)benzenes (X = Cl, I) via lithiation/borylation, electrophilic aromatic borylation, and Si/B exchange. The heteroatom distribution in meets the requirements for multiple resonance thermally activated delayed fluorescence (MR-TADF). Indeed, emits green light (λ = 523 nm; Φ = 85%; CHCl) with a small fwhm of 0.

Confined Lewis Pairs: Investigation of the X →Si Interaction in Halogen-Encapsulating Silafulleranes.

A joint theoretical and experimental study on 32 endohedral silafullerane derivatives [X@Si Y ] (X=F-I; Y=F-I, H, Me, Et) and -[Cl@Si H Y ] (Y=F-I) is presented. First, we evaluated the structure-determining template effect of Cl in a systematic series of concave silapolyquinane model systems. Second, we investigated the X →Si interaction energy ( ) as a function of X and Y and found the largest values for electron-withdrawing exohedral substituents Y.

B,N-Doped Heptacenes: Ambipolar Charge-Transfer Compounds with Deep LUMO Levels.

The B,N-doped heptacene in which two ,'-dihydrophenazine units are linked by two BMes bridges (Mes = mesityl) was synthesized via fourfold Buchwald-Hartwig coupling between 2,3,6,7-tetrachloro-9,10-dimesityl-9,10-dihydro-9,10-diboraanthracene and -phenylenediamine (BuXPhos-Pd-G3, DBU/NaOTf, 2-MeTHF, 50 °C, 16 h). Upon exposure to ambient air, is oxidized to its ,'-dihydro form ; further oxidation with MnO furnishes the di(phenazine) derivative . Stirring under a blanket of H in the presence of Pd/C hydrogenates back to and ultimately .

Vicinal Vinylation of Boron-Doped Acenes via Heck Coupling.

Silylated and halogenated benzenes 1,2-(MeSi)-4,5-X-CH [X = Br (), I ()] are versatile synthetic building blocks. was prepared from known 1,2-(MeSi)-4,5-Cl-CH via C-Cl borylation/bromodeboronation; CuI-catalyzed Br/I exchange on affords . or and BBr yield 9,10-dibromo-9,10-dihydro-9,10-diboraanthracenes (DBAs) or .

Brominated [20]silafulleranes: pushing the limits of steric loading.

Starting from the perhydrogenated silafullerane [BuN][Cl@Si(SiH)H], treatment with BBr leads to partially and exhaustively brominated clusters, [BuN][Cl@Si(SiBrH)Br] (120 eq. BBr, room temperature, 30 min) and [BuN][Cl@Si(SiBr)Br] (300 eq. BBr, 130 °C, 3 d).

Synthesis, bridgehead functionalization, and photoisomerization of 9,10-diboratatriptycene dianions.

9,10-Diboratatriptycene salts M[RB(μ-CH)BR] (R = H, Me; M = Li, K, [-BuN]) have been synthesized [4 + 2] cycloaddition between doubly reduced 9,10-dihydro-9,10-diboraanthracenes M[DBA] and benzyne, generated from CHF and CHLi or LiN(-Pr). [HB(μ-CH)BH] reacts with CHCl to form quantitatively the bridgehead-derivatized [ClB(μ-CH)BCl], while twofold H abstraction with B(CF) in the presence of SMe leads cleanly to the diadduct (MeS)B(μ-CH)B(SMe). Photoisomerization of K[HB(μ-CH)BH] (THF, medium-pressure Hg lamp) provides facile access to diborabenzo[]fluoranthenes, a little explored form of boron-doped polycyclic aromatic hydrocarbons.

Regioselective Derivatization of Silylated [20]Silafulleranes.

Silafulleranes with endohedral Cl ions are a unique, scarcely explored class of structurally well-defined silicon clusters and host-guest complexes. Herein, we report regioselective derivatization reactions on the siladodecahedrane [BuN][Cl@Si(SiCl)Cl] ([BuN][]), which has its cluster surface decorated with 12 SiCl and 8 Cl substituents in perfect symmetry. The room-temperature reaction of [BuN][] with excess BuAlH in -difluorobenzene (DFB) furnishes perhydrogenated [BuN][Cl@Si(SiH)H] ([BuN][]) in 50% yield; the non-pyrophoric [] is the largest structurally authenticated (by X-ray diffraction) hydridosilane known to date.

Catalyst-free diboration and silaboration of alkenes and alkynes using bis(9-heterofluorenyl)s.

Diboration and silaboration reactions are prominent tools to introduce valuable functional groups into organic substrates. To date, most diboranes(4) and silylboranes used for this purpose are electronically and/or kinetically stabilized and require activation by a catalyst. We show here that the tetraaryl (μ-hydrido)diborane(4) anion [3] and the silyl (hydrido)borate ([4])/MeSiBr system react spontaneously with the archetypal olefin ethylene in the absence of a catalyst.

Group IV heteroadamantanes: synthesis of SiSn and site-selective derivatization of SiGe.

The mixed heteroadamantanes SiGe and SiSn are readily accessible from MeECl/SiCl/cat. Cl (4 × EMe, 2 × SiCl, 4 × Si-SiCl vertices; E = Ge, Sn). Different from SiGe, two skeletal isomers are formed in the case of SiSn.

Synthesis and Reactivity of a Cyclooctatetraene-Like Polyphosphorus Ligand Complex [Cyclo-P ].

The thermolysis of Cp'''Ta(CO) with white phosphorus (P ) gives access to [{Cp'''Ta} (μ,η -P )] (A), representing the first complex containing a cyclooctatetraene-like (COT) cyclo-P ligand. While ring sizes of n >6 have remained elusive for cyclo-P structural motifs, the choice of the transition metal, co-ligand and reaction conditions allowed the isolation of A. Reactivity investigations reveal its versatile coordination behaviour as well as its redox properties.

Across the Dimensions: A Three-Component Self-Assembly of Pentaphosphaferrocene-based Coordination Polymers.

Pentaphosphaferrocenes [Cp Fe(η -P )] (Cp*=η -C Me ) (A), Cp''=η -C H tBu -1,3 (B)) are excellent building blocks for polymeric assemblies in supramolecular chemistry in combination with coinage metal salts of weakly coordinating anions such as AgSbF . Adding rigid aromatic dinitriles ortho/meta/para-(NC) C H in a one-pot reaction between [Cp Fe(η -P )] and AgSbF leads to various coordination polymers (CPs) by a three-component self-assembly. The sterical demand of the differently substituted cyclopentadiene ligands as well as the rigid constitution of the isomeric dinitriles (NC) C H play a key role in the formation of the isolated CPs.

Dope it with germanium: selective access to functionalized SiGe heterocycles.

The Cl diadduct [BuN][A·2Cl] of the mixed cyclohexatetrelane (SiCl)(GeMe), A, is accessible from MeGeCl, 6 eq. SiCl, and 2 eq. [BuN]Cl in one step (96%).

Three- and Five-Membered Anionic Chains of Pnictogenylboranes.

An unprecedented family of three- and five-membered substituted anionic derivatives of parent pnictogenylboranes is herein reported. Reacting various combinations of the pnictogenylboranes H E'-BH -NMe (E'=P, As) with pnictogen-based nucleophiles MER1R2 (E=P, As; R1=H, R2= Bu; R1=R2=Ph; M=Na, K) allows for the isolation of the unsymmetrical products [Na(18-crown-6)][H E'-BH -EH Bu] (3: E=E'=P; 4: E=E'=As; 5: E=As, E'=P) and [M(C)][H E'-BH -EPh ] (7: E=E'=P, M=Na, C=18-crown-6; 8: E=E'=As; M=K, C=[2.2.

A Hydride-Substituted Homoleptic Silylborate: How Similar is it to its Diborane(6)-Dianion Isostere?

The B-nucleophilic 9H-9-borafluorene dianion reacts with 9-chloro-9-silafluorene to afford air- and moisture-stable silylborate salts M[Ar (H)B-Si(H)Ar ] (M[HBSiH], M=Li, Na). Li[HBSiH] and Me SiCl give the B-pyridine adduct Ar (py)B-Si(H)Ar ((py)BSiH) or the chlorosilane Li[Ar (H)B-Si(Cl)Ar ] (Li[HBSiCl]) in C H -pyridine or THF. In both cases, the first step is H abstraction at the B center.

Late-stage derivatization of a (B,O)-doped perylene.

Regioselective di- and tetrabrominations of the (B,O)-perylene 1 afford derivatives 2-4. Despite their poor solubility, 2 and 4 could be used in Stille-type coupling reactions to introduce two CCMe (5) or four CC(-CHBu) substituents (6), respectively. The alkynylated derivatives show blue-green photoluminescence with appreciable quantum efficiencies.

Structural Chemistry of Giant Metal Based Supramolecules.

The review presents a bird-eye view on the state of research in the field of giant nonbiological discrete metal complexes and ions of nanometer size, which are structurally characterized by means of single-crystal X-ray diffraction, using the crystal structure as a common key feature. The discussion is focused on the main structural features of the metal clusters, the clusters containing compact metal oxide/hydroxide/chalcogenide core, ligand-based metal-organic cages, and supramolecules as well as on the aspects related to the packing of the molecules or ions in the crystal and the methodological aspects of the single-crystal neutron and X-ray diffraction of these compounds.

Unusual molecular complexes of antimony fluoride dimers with acetonitrile and pyridine: structures and bonding.

The structures of two new molecular complexes of antimony pentafluoride with pyridine (Py) and acetonitrile (AN), SbF·Py and SbF·AN, and a molecular complex of antimony trifluoride SbF·Py and its ionic derivative [HPy][SbF] in the solid state have been determined by single crystal X-ray structural analysis. The complexes SbF·AN and SbF·Py are the first structurally characterized compounds of dimeric antimony fluorides. To reveal the nature of bonding in the complexes and their stability, DFT computations of the electronic structure and thermodynamic characteristics were performed, in particular the analysis of the electrostatic potentials, the orbital interactions and the topology.

Insertion of Phosphenium Ions into a Bicyclo[1.1.0]Tetraphosphabutane Iron Complex.

By reacting [{Cp‴Fe(CO)}(µ,η-P)] () with in situ generated phosphenium ions [PhP][A] ([A] = [OTf] = [OSCF], [PF]), a mixture of two main products of the composition [{Cp‴Fe(CO)}(µ,η-P(CH))][PF] ( and ) could be identified by extensive P NMR spectroscopic studies at 193 K. Compound was also characterized by X-ray diffraction analysis, showing the rarely observed bicyclo[2.1.

Use of a -P building block - a way to networks of host-guest assemblies.

Despite the proven ability to form supramolecular assemblies coordination to copper halides, organometallic building blocks based on four-membered -P ligands find only very rare application in supramolecular chemistry. To date, only three types of supramolecular aggregates were obtained based on the polyphosphorus end-deck complexes CpTa(CO)(η-P) (: Cp = Cp''; : Cp = Cp'''), with none of them, however, possessing a guest-accessible void. To achieve this target, the use of silver salts of the weakly coordinating anion SbF was investigated as to their self-assembly in the absence and in the presence of the template molecule PSe.

Versatile Coordination of Ag and Cu Ions towards cyclo-As Ligands.

The reactions of the cyclo-As complex [Cp*Fe(η -As )] (B) with the Ag and Cu salts of the weakly coordinating anion (WCA) [FAl{OC F (C F )} ] ([FAl] ) are studied. These reactions allow the synthesis of the mononuclear complexes [M(η  : η -B) ][FAl] (M=Ag (1), Cu (2)) when a ratio of B/M(FAl) 2 : 1 is used. Compound 1 shows an unusual disorder of the central Ag cation between two π-coordinating cyclo-As ligands, which is absent in 2 pointing to a weak interaction of the Ag center towards the cyclo-As ligands in B.