Bis(2-pyridyl) and Tris(2-pyridyl) Compounds of Gallium and Indium a Redox-Transmetalation Route.

Reactions of the tris(2-pyridyl)lead(II) compound [LiPb(2-py)] () with trialkyl compounds of the group 13 elements gallium and indium resulted in the bis(2-pyridyl) and tris(2-pyridyl) gallate complexes [LiGaEt(2-py)] (), [LiGaR(2-py)(THF)] (R = Pr (), Bu ()), [LiGaBu(2-py)] ('), and [LiGaMe(2-py)] (), as well as corresponding indium complexes of general composition [LiInR(2-py)] (R = Me (), Et ()). The formation of these compounds can be assumed as a rapid degradation of initially formed Pb-M adducts (M = Ga or In) as found for [BuGa{Pb(2-py)Li}] (). In addition, the redox transmetalation route was used for the synthesis of [LiInI(2-py)(THF)] ().

Penta- and hexaorganostannate(iv) complexes based on O-heterocyclic ligands.

In the present study, the synthesis of homoleptic five- and six-coordinate heteroaryl tin(iv) compounds using two O-heterocyclic substituents, 2-furyl (2-fu) and 2-benzofuryl (2-fu) ligands is described. The compounds were obtained as their lithium salts [Li(OEt)Sn(2-fu)] (1), [Li(tmeda)][Sn(2-fu)] (tmeda = N,N,N',N'-tetramethylethylenediamine) (2) and [Li(thf)][Sn(2-fu)] (3), featuring both an intramolecular coordination of the counterions by the anionic hypercoordinate tin(iv) species found in 1 as well as solvent separated cation/anion pairs for compounds 2 and 3. In addition, the co-crystalline complex [K(thf)Sn(2-fu)]·[K(thf)Sn(2-fu)] (4a·4b) was achieved.

Dilithium hexaorganostannate(IV) compounds.

Hypercoordination of main-group elements such as the heavier Group 14 elements (silicon, germanium, tin, and lead) usually requires strong electron-withdrawing ligands and/or donating groups. Herein, we present the synthesis and characterization of two hexaaryltin(IV) dianions in form of their dilithium salts [Li2(thf)2{Sn(2-py(Me))6}] (py(Me)=C5H3N-5-Me) (2) and [Li2{Sn(2-py(OtBu))6}] (py(OtBu)=C5H3N-6-OtBu) (3). Both complexes are stable in the solid state and solution under inert conditions.

Versatile reactivity of a lithium tris(aryl)plumbate(II) towards organolanthanoid compounds: stable lead-lanthanoid-metal bonds or redox processes.

Redox chemistry: Redox-active europium complexes based on a new tris(2-pyridyl)plumbate ligand are described. Reactions of [LiPb(2-py(R))3(thf)] (py(R) = C5H3-6-OtBu) with tri- or divalent lanthanoid metals resulted in the first stable Pb-Ln-bonded complexes or unprecedented redox reactions, involving, for example, the pentametallic complex depicted.

Syntheses and structures of lanthanoid(II) complexes featuring Sn-M (M = Al, Ga, In) bonds.

The reactions of the tris(pyridyl)tin(II) derivative [Li(thf)Sn(2-py(R))(3)] (py(R) = C(5)H(3)N-5-Me) (1) with the heavier group 13 alkyl compounds MEt(3), M = Ga or In, have been carried out. These led to formation of [{Li(thf)Sn(2-py(R))(3)}MEt(3)] adducts, which exhibit long Sn-M bonds and can be used for further lanthanoid metal coordination via the salt metathesis reaction with [Eu(Cp*)(2)(OEt(2))] (Cp* = η(5)-C(5)Me(5)) to give complexes [Eu{Sn(2-py(R))(3)MEt(3)}(2)]. In contrast, addition of the lighter group 13 analogue, (AlMe(3))(2), to 1 resulted in a pyridyl transfer reaction, yielding dimeric [AlMe(2)(2-py(R))](2).

Tin-lanthanoid donor-acceptor bonds.

Reactions of a lithium tris(2-pyridyl)stannate with lanthanoid metal organic compounds resulted in the formation of novel donor-acceptor complexes, containing a low valent tin-lanthanoid bond; DFT calculations reveal that this bond exhibits some covalent character.

Highly sensitive protein detection based on lanthanide chelates with antenna ligands providing a linear range of five orders of magnitude.

Protein detection is an important task for pharmaceutical and clinical research today. Numerous protein staining techniques exist but are limited regarding their sensitivity and often narrow linear quantification ranges. To the best of our knowledge, this is the first description of a novel class of lanthanide chelatators, which absorb in the lower energy region at 360 nm.

A simple thermodynamic model for rationalizing the formation of self-assembled multimetallic edifices: application to triple-stranded helicates.

Reaction of the bis-tridentate ligand bis[1-ethyl-2-[6'-(N,N-diethylcarbamoyl)pyridin-2'-yl]benzimidazol-5-yl]methane (L2) with Ln(CF(3)SO(3))(3).xH(2)O in acetonitrile (Ln = La-Lu) demonstrates the successive formation of three stable complexes [Ln(L2)(3)](3+), [Ln(2)(L2)(3)](6+), and [Ln(2)(L2)(2)](6+). Crystal-field independent NMR methods establish that the crystal structure of [Tb(2)(L2)(3)](6+) is a satisfying model for the helical structure observed in solution.