Part A: Synthesis and reactivity of diastereomeric rhenium halfsandwich thiolate complexes and Part B: Monoanionic tungsten carbonyl complexes: Synthesis, structure and interaction with cell membranes

Teil A behandelt zunächst die Synthese verschiedener achiraler und chiraler Phosphane. Die Chiralität kann sowohl in der Seitenkette als auch am Phosphoratom selbst vorliegen. Einige Phosphane tragen zusätzlich ein weiteres Donoratom (O oder S) in der organischen Seitenkette. Reaktion der Phosphane mit dem at-metal-chiralen Komplex [CpRe(CO)(NO)(NCCH3)]BF4 liefert diastereomere Komplexe des Typs [CpRe(CO)(NO)(PR3)]BF4 mit Metall- und Ligand-zentrierter Chiralität. Weitere Umsetzungen führen zu neutralen Methyl- und Thiolat-Komplexen [CpRe(NO)(PR3)(L)] (L = Me, SCH2R'). Säureinduzierte Abspaltung der Methyl-Gruppe führt zu 16-Valenzelektronen-Komplexen, die sich intramolekular über die weitere Donorfunktion im Phosphan stabilisieren lassen. Die Oxidation der Thiolat-Komplexe mit [Ph3C]BF4 führt zu Thioaldehyd-Komplexen [CpRe(NO)(PR3)(S=C(H)R')]BF4. Teil B beschäftigt sich mit der Synthese von Wolfram-Komplexen des allgemeinen Typs Et4N[W(CO)5(SR)] (R = Aryl, Alkyl) sowie cis-Et4N[W(CO)4(SSCQ)] (Q = OR, NR2, R). Umsetzung von Et4N[W(CO)5(SR)] mit Phosphanen liefert die entsprechenden Phosphan-substituierten Komplexe cis-Et4N[W(CO)4(PR'3)(SR)] bzw. fac-Et4N[W(CO)3(PR'3)2(SR)]. Im Falle von cis-Et4N[W(CO)4(SSCQ)] (Q = OR, NR2, R) verlaufen die Umsetzungen mit Phosphanen uneinheitlich. Die Wechselwirkung einiger Wolfram-Komplexe mit der Zellmembran von Sp2- und Jurkat-Zellen wurde mittels Elektrorotationsmessungen untersucht.Part A deals first with the synthesis of several achiral and chiral phosphines. The stereogenic centre can be situated at the side chain or at the phosphorus atom. Some phosphines contain another donor atom (O or S) in their side chains. The reaction of the phosphines with the at-metal-chiral complex [CpRe(CO)(NO)(NCCH3)]BF4 leads to diastereomeric complexes of the type [CpRe(CO)(NO)(PR3)]BF4 with metal- and ligand-centred chirality. Further reactions result in the formation of neutral methyl- and thiolate complexes [CpRe(NO)(PR3)(L)] (L = Me, SCH2R'). The methyl group can be cleaved under acidic conditions, giving rise to 16 valence electron complexes. They can be stabilised intramolecularly by the additional donor function of the phosphines. Oxidation of the thiolate complexes with [Ph3C]BF4 results in the formation of thioaldehyde complexes [CpRe(NO)(PR3)(S=C(H)R')]BF4. Part B deals with the synthesis of tungsten complexes of the general formula Et4N[W(CO)5(SR)] (R = Aryl, Alkyl) and cis-Et4N[W(CO)4(SSCQ)] (Q = OR, NR2, R). The reaction of Et4N[W(CO)5(SR)] with phosphines leads to the corresponding phosphine-substituted complexes cis-Et4N[W(CO)4(PR'3)(SR)] or fac-Et4N[W(CO)3(PR'3)2(SR)]. In the case of cis-Et4N[W(CO)4(SSCQ)] (Q = OR, NR2, R), the reactions with phosphines are nonuniform. The interaction of several tungsten complexes with the cell membrane of Sp2- and jurcat cells is investigated using the electrorotation technique

Crystal structures of [PhLi center dot(-)-sparteine](2), [PhOLi center dot(-)-sparteine](2), and the mixed aggregate [PhLi center dot PhOLi center dot 2(-)-sparteine]

Crystal structure determination of adducts of sparteine and PhLi, (-)-sparteine and PhOLi and of sparteine and PhLi/PhOLi reveal a four-membered ring with two lithium centers, each capped by a (-)-sparteine ligand, as central motif of all structure. Quantum-chemical calculations show that the mixed aggregate [PhLi center dot PhOLi center dot 2(-)-sparteine] is energetically more favorable than the model system {1/2[PhLi center dot(-)-sparteine](2) + 1/2[PhOLi center dot(-)-sparteine](2)}

Ethynyl[2.2]paracyclophanes and 4-isocyano[2.2]paracyclophane as ligands in organometallic chemistry

An alternative synthesis of (±)-4-ethynyl[2.2]paracyclophane (PCPsingle bondCtriple bondCH) (5) and 4,16-diethynyl[2.2]paracyclophane (6) via the Corey–Fuchs reaction has been developed. The olefinic intermediate 4-dibromovinyl[2.2]paracyclophane (3) has been isolated and structurally characterized. The racemic terminal alkyne 5 was employed as starting material for assembling of a luminescent extended π-conjugated system containing a thiophene unit and for a catalytic bis-silylation reaction yielding the olefinic dithioether Z-PhSCH2Me2SiC(H)double bondC(PCP)SiMe2CH2SPh (9). The dimetallatetrahedran [Co2(CO)6(μ-η2–PCP–CCH)] (10) has been prepared and its crystal structure determined by an X-ray diffraction analysis. Alkyne 5 has also been used for the preparation of the Pt(0) complex [Pt(PPh3)2(PCPsingle bondCtriple bondCH)] (11) and the heterodinuclear dimetallacyclopentenone [(OC)2Fe{μsingle bondC(double bondO)C(PCP)double bondC(H)}(μ-dppm)Pt(PPh3)] (12). The synthesis and reactivity of 4-isocyano[2.2]paracyclophane (15) towards heterobimetallic iron–platinum and palladium–platinum complexes is also presented. Opening of the dative iron → platinum bond of [(OC)4Fe(μ-dppm)PtCl2] (16) occurred upon addition of 15 to a CH2Cl2 solution of 16 leading to [(OC)4Fe{μ-dppm}PtCl2(Ctriple bondNsingle bondPCP)] (17). Treatment of [ClPd(μ-dppm)2PtCl] (18) with isocyanide 15 in a 1:1 ratio affords the A-frame compound [ClPd(μ-dppm)2(μ-Cdouble bondNsingle bondPCP)PtCl] (19), resulting from formal insertion of 15 into the Pd–Pt bond. Addition of 2 equiv. of 15–18 leads to the ionic A-frame compound [ClPd(μ-dppm)2(μ-Cdouble bondNsingle bondPCP)Pt(Ctriple bondNsingle bondPCP)]Cl (20)

Phloretin-induced changes of lipophilic ion transport across the plasma membrane of mammalian cells.

The adsorption of the hydrophobic anion [W(CO)(5)CN](-) to human lymphoid Jurkat cells gave rise to an additional anti-field peak in the rotational spectra of single cells, indicating that the cell membrane displayed a strong dielectric dispersion in the kilohertz to megahertz frequency range. The surface concentration of the adsorbed anion and its translocation rate constant between the two membrane boundaries could be evaluated from the rotation spectra of cells by applying the previously proposed mobile charge model. Similar single-cell electrorotation experiments were performed to examine the effect of phloretin, a dipolar molecule known to influence the dipole potential of membranes, on the transport of [W(CO)(5)CN](-) across the plasma membrane of mammalian cells. The adsorption of [W(CO)(5)CN](-) was significantly reduced by phloretin, which is in reasonable agreement with the known phloretin-induced effects on artificial and biological membranes. The IC(50) for the effect of phloretin on the transport parameters of the lipophilic ion was approximately 10 microM. The results of this study are consistent with the assumption that the binding of phloretin reduces the intrinsic dipole potential of the plasma membrane. The experimental approach developed here allows the quantification of intrinsic dipole potential changes within the plasma membrane of living cells