4th EucheMs chemistry congress

Poster Session 1
s989
chem. Listy 106, s587–s1425 (2012)
Poster session 1 - inorganic Chemistry
P - 0 2 5 6
redox direCted ProCeSSeS in the deSiGn of
noveL nAnoSCALe heteroPoLyACidS
A. KondinSKi 1 , n. izArovA 1 , n. nSouLi 1 , B. BASSiL 1 ,
u. Kortz 1
1 Jacobs University, School of Engineering and Science,
Bremen, Germany
Polyoxometalates (POMs) are an exciting class of discrete
metal-oxygen cage complexes with a tremendous variety of
structures, compositions and properties. [1] . In this work we
decided to explore the use of oxidizing agents such as sodium
chromate in the synthesis of novel lanthanide containing
tungstoarsenates. In particular, when using the trilacunary
lone-pair-containing [AsIIIW O ] 9 33 9- as the POM precursor, there is
a partial in-situ oxidation of the AsIII heteroatom of the POM
precursor, leading to a large mixed-valent AsIII/AsV polyanions
with formula [Ln As 12 III
8AsV 2W90O328 (H2O) 36 (OAc) 4 ]48- (Ln=Gd III ,
TbIII , DyIII , HoIII ErIII , TmIII , YbIII , LuIII ). The same reaction
conditions in presence of cerium(III) ions lead to in-situ oxidation
of CeIII ions to CeIVfollowed by a self-assembly into the novel
tetrameric polyanion [CeIV 4AsIII 4W41O149 ]24- .
Keywords: polyoxometalate; self-assembly; in-situ oxidation;
lanthanoids; tungstoarsenate;
4 th EucheMs chemistry congress
P - 0 2 5 7
LithiAted SuLfoxideS – ALPhA-SuLfinyL
funCtionALized CArBAnionS
G. LudwiG 1 , A. hoPPe 1 , M. Bette 1 , t. rüffer 2 ,
d. SteinBorn 2
1 Institute of Chemistry, Inorganic Chemistry, Halle (Saale),
Germany
2 Institute of Chemistry, Inorganic Chemistry, Chemnitz,
Germany
α-Heteroatom functionalized alkyl lithium compounds of
the type LiCHRYR' n (Y = N, P, O, S, Cl, …) exhibit a unique
reactivity; thus, for example, those with electronegative groups
YR' n may react as carbenoids. 1 A further point of interest is the
configurational stability of the carbanionic C atoms. 2 Sulfur
functionalized lithium compounds, among them lithiated
sulfoxides Li[CRR'S(O)R”], have been hardly investigated in this
respect. 3–5 In the present work, lithiated sulfoxides of the type
[Li 2 {CRR'S(O)Ph} 2 (TMEDA) 2 ] (i) were obtained by direct
metallation of the respective sulfoxides with n-BuLi/TMEDA. In
the solid state, in type i compounds, no Li–C interactions were
recognized; thus, there is a “free” α-carbanionic center having a
planar configuration (see the structural image with R/R' =Me/Me
as example). The dynamics of type i lithium compounds in
solution was investigated by low-temperature NMR
measurements and, moreover, these results were confirmed by
DFT calculations. Furthermore, here we report on reactions of
type i compounds with various electrophiles and their
diastereoselectivity as well as on the decomposition of type i
compounds exhibiting a carbenoid reactivity.
references:
1. G. Köbrich, Angew. Chem. 1972, 84, 557.
2. A. Basu, S. Thayumanavan, Angew. Chem., Int. Ed. 2002,
41, 716.
3. M. Marsch, W. Massa, K. Harms, G. Baum, G. Boche,
Angew. Chem., Int. Ed. 1986, 25, 1011.
4. A. Maercker, R. Schuhmacher, W. Buchmeier, H. D. Lutz,
Chem. Ber. 1991, 124, 2489.
5. D. J. Cram, S. H. Pine, J. Am. Chem. Soc. 1963, 85, 1096.
Keywords: carbanion; carbenoid; lithiated sulfoxide;
AUGUst 26–30, 2012, PrAGUE, cZEcH rEPUbLIc