Wolfram W. Seidel

A new class of azadipnictiridines generated by an unusual rearrangement reaction.

Dipnictadiazanediyls, [E(μ-NR)]2 (E = P, As), the pnictogen analogues of cyclobutandiyl, were found to react readily with alkynes forming [2.1.1]bicyclic structures. These, in turn, rearrange in an unprecedented reaction to [3.1.o]bicycles leading to the isolation of the first azadiarsiridine and the determination of its solid-state structure. All new species were comprehensively characterized, and the reaction pathways and bonding situations were computationally studied.

Ethenedithione (SCCS): Trapping and Isomerization in a Cobalt Complex†

Swing bridge: The triplet species ethenedithione has been generated within the coordination sphere of cobalt, leading to a dinuclear μ-η(2)-η(2)-C(2)S(2) complex (see picture: C gray, Co blue, P purple, S yellow). Depending on the solvent, the C(2)S(2) moiety displays a transoid or a cisoid geometry. This isomerization step changes the sign of the magnetic coupling between the cobalt centers.

Ultrafast Energy Transfer in Dinuclear Complexes with Bridging 1,10-Phenanthroline-5,6-Dithiolate

We report herein the preparation and characterization of dinuclear complexes with the bridging ligand 1,10-phenanthroline-5,6-dithiolate (phendt2-) bearing Ru(bpy)2 or Ir(ppy)2 at the diimine moiety and Ni(dppe), Ni(dppf), CoCp, RhCp*, and Ru( p-Me-iPr-benzene) at the dithiolate unit. In comparison with the mononuclear precursors used in the synthesis, all dinuclear complexes were characterized by absorption and photoluminescence spectroscopy as well as cyclic voltammetry. Because of the beneficial spectral and electrochemical properties of the Ir/Co complex for a light-driven charge separation, this complex was investigated in detail by time-resolved luminescence {nanosecond (ns)-resolution} and transient absorption spectroscopy {femtosecond (fs)-resolution}. All measurements supported by DFT calculations show that the observed effective luminescence quenching by the dithiolate coordinated metal is caused by an ultrafast singlet-singlet Dexter energy transfer.

Substitutionsreaktionen An Alkinkomplexen Des Nb(Iii) Und Mo(Ii) Mit Dem Liganden Bis(Benzylthio)Acetylen

Substitution reactions of the bis(benzylthio)acetylene complexes [Tp′Nb(BnSC2SBn)Cl2] and [Tp′Mo(BnSC2SBn)(CO)2](PF6) (Tp′ = hydro-tris(3,5-dimethyl)pyrazolylborate, Bn = benzyl) have been investigated. The coordination of the alkyne ligand turned out to be very stable, while one chloride ion in [Tp′Nb(BnSC2SBn)Cl2], and either one or both of the CO ligands in [Tp′Mo(BnSC2SBn)(CO)2](PF6) can be substituted. The dissociative mechanism of the reactions with [Tp′Mo(BnSC2SBn)(CO)2](PF6) and [Tp′ Mo(BnSC2SBn)(CO)Cl] leads to the primary and exclusive reaction with the solvent. In the course of these studies the structures of [Tp′Nb(BnSC2SBn)Cl2], [Tp′Mo(BnSC2SBn)(CO)(MeCN)](PF6), [Tp′Mo(BnSC2SBn)(CO)Cl] and [Tp′Mo(BnSC2SBn)Cl2][Tp′Mo(BnSC2SBn)ClF] have been determined by X-ray diffraction. Comparison of the closely related compounds allows conclusions how the number of d electrons and the character of the co-ligands influence the alkyne bonding

Das Koordinationsverhalten des Acetylendisulfids Bis(benzylthio)acetylen gegenüber nullwertigen Metallkomplexen des W, Co und Pt/The Coordination Behavior of the Acetylenedisulfide Bis(benzylthio)acetylene with Zero-valent Metal Complexes of W, Co and Pt

Abstract Synthesis and characterization of the alkyne complexes [Co2(CO)6(L)], [W(CO)(L)3] and [Pt(PPh3)2(L)] with L = BnSC2SBn (Bn = benzyl) are described. X-Ray diffraction studies of [W(CO)(L)3] and [Co2(CO)5(L)]2 reveal that the donor ability of the sulfide group depends on the electronic and steric situation in the particular metal complex. The specific donor strength of sulfidesubstituted alkynes in their complexes is discussed considering the IR and NMR spectroscopic data.