9-Triptycenyl complexes of group 13 and 15 halides and hydrides

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.

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.

Stibine as a reagent in molecular chemistry - targeted synthesis of primary and secondary stibanyl-gallanes and their lighter homologues

The reactions of SbH₃ with one or two equivalents of (Dipp₂NacNac)Ga (Dipp₂NacNac = HC{C(Me)N(Dipp)}₂; Dipp = 2,6-iPr₂C₆H₃) yield the primary and secondary stibanes (Dipp₂NacNac)GaH(SbH₂) (3) and {(Dipp₂NacNac)GaH}₂(SbH) (5). Their lighter homologs were obtained from the analogous reactions with phosphine and arsine. All compounds were characterized using heteronuclear NMR-spectroscopy, IR-spectroscopy and single-crystal X-ray diffraction.

Synthesis of heteroleptic gallium-substituted antimony hydrides by stepwise β-H elimination

Heteroleptic stibanes Cp*(R)SbCl (R = Dip 1, N(SiMe₃)₂2, OB(NDipCH)₂3; Cp* = C₅Me₅; Dip = 2,6-i-Pr₂-C₆H₃) react with monovalent gallanediyl LGa (L = HC[C(Me)N(Dip)]₂) with elimination of 1,2,3,4-tetramethylfulvene, yielding heteroleptic metal-stabilized Sb hydrides [L(Cl)Ga](R)SbH (R = Dip 4, N(SiMe₃)₂5, OB(NDipCH)₂6). Compounds 1-6 were characterized by heteronuclear NMR (¹H, ¹¹B, ¹³C) and IR spectroscopy, and the solid-state structures of 4-6 were determined by single-crystal X-ray diffraction. A close correlation between the ¹H NMR chemical shift of the hydride ligand and the electronegativity of the Sb-coordinating atoms was revealed.

Hydrostibination

A rigid naphthalenediamine framework has been used to prepare antimony hydrides that feature LUMO shapes and energies similar to those found in secondary boranes. By exploiting this feature, we introduce the first examples of uncatalyzed hydrostibination reactions of robust C≡C, C=C, C=O, and N=N bonds as new elementary hydrometalation reactions analogous to hydroboration. These results endorse the notion of a diagonal relationship between the lightest p-block element and the heaviest Group 15 elements and may lead to the conception of novel reaction chemistry.

A study of di(amino)stibines with terminal Sb(iii) hydrogen-ligands by X-ray- and neutron-diffraction

The bis(amidodimethyl)disiloxane ligands [O{SiMe2NR}2]2- (R = 2,6-Me2C6H3 (Ar') and 2,6-iPr2C6H3 (Ar), abbreviated [NONR]2-, are a stable support for Sb(iii) complexes of general formula Sb(NONR)X (X = Cl, H). The compounds are monomeric in the solid-state, with bidentate N,N'-coordination of the [NONR]2- and terminal chloride/hydrogen-ligands. Sb(NONAr')H was analyzed by single-crystal neutron diffraction, giving the first accurate parameters for the Sb-H bond to an antimony(iii) centre.

Nonconjugated Hydrocarbons as Rigid-Linear Motifs: Isosteres for Material Sciences and Bioorganic and Medicinal Chemistry

Nonconjugated hydrocarbons, like bicyclo[1.1.1]pentane, bicyclo[2.2.2]octane, triptycene, and cubane are a unique class of rigid linkers. Due to their similarity in size and shape they are useful mimics of classic benzene moieties in drugs, so-called bioisosteres. Moreover, they also fulfill an important role in material sciences as linear linkers, in order to arrange various functionalities in a defined spatial manner. In this Review article, recent developments and usages of these special, rectilinear systems are discussed. Furthermore, we focus on covalently linked, nonconjugated linear arrangements and discuss the physical and chemical properties and differences of individual linkers, as well as their application in material and medicinal sciences.

Synthesis and Catalytic Applications of a Triptycene-Based Monophosphine Ligand for Palladium-Mediated Organic Transformations

1-Methoxy-8-(diphenylphosphino)triptycene (1), featuring high structural rigidity and steric bulkiness around the phosphine functionality, was synthesized as a new chiral monophosphine ligand for transition metal-catalyzed reactions. In the presence of 5-10 mol ppm (i.e., 0.0005-0.001 mol %) Pd(OAc)₂ and 1 (2 equiv for Pd), Suzuki-Miyaura cross-coupling reactions of aryl bromides and arylboronic acids proceeded effectively under mild atmospheric conditions to give the corresponding biaryl compounds in a high yield. The single-crystal X-ray analysis of a Pd(II) complex of 1 revealed its coordination structure, in which two homochiral molecules form a dimer, suggesting that triptycene could provide a chiral environment for asymmetric organic transformations. In fact, optically active 1 obtained by optical resolution showed good enantioselectivity in the palladium-catalyzed asymmetric hydrosilylation of styrene, which represents, for the first time, the asymmetric catalytic activity of triptycene-based monophosphine ligands.