Manfred Scheer

Temperature controlled reversible change of the coordination modes of the highly symmetrical multitopic ligand to construct coordination assemblies: experimental and theoretical studies.

By fine-tuning the reaction temperature to 5, 15, 30, and 50 degrees C, respectively, four different complexes, [Cd(HC4O4)2(H2O)4] (1), [Cd4(C4O4)4(H2O)16].(H2O)2 (2), [Cd(C4O4)(H2O)2] (3), and [Cd(C4O4)(H2O)2] (4), were formed successfully from the identical initial reaction mixture. Moreover, an unprecedented reversible interconversion among the four complexes at the corresponding reaction temperatures mediated by the mother liquor was observed.

P4 activation by main group elements and compounds.

An overview about the activation of white phosphorus, P4 with main group elements and compounds is given.

Unprecedented interweaving of single-helical and unequal double-helical chains into chiral metal–organic open frameworks with multiwalled tubular structures

Two novel chiral metal-organic open frameworks with unprecedented multiwalled tubular channels and interweaving of single-helical and unequal double-helical units were reported, which possess novel four-connected 4(2)8(3)10 topology and represent the first examples of functional metal-organic frameworks based on both flexible tripodal and flexible bisdentate ligands.

Pentaphosphaferrocene as a Linking Unit for the Formation of One‐ and Two‐Dimensional Polymers

Different copper halide, different copper product: The cyclo-P5-ligand complex [Cp*Fe(5-P5)] (1; Cp*=C5Me5) reacts with CuBr and CuI to give two-dimensional networks in which 1 is the linking unit. However, a novel one-dimensional-chain coordination polymer (see picture) is formed with CuCl.

A Spherical Molecule with a Carbon‐Free Ih‐C80 Topological Framework

The complete encapsulation of ortho-carborane by a fullerene-like building-block system consisting of pentaphosphaferrocene and Cu(I)Cl leads to the formation of the spherical supermolecule C(2)B(10)H(12) section sign[{Cp*Fe(eta(5)-P(5))}(12)(CuCl)(20)]. This product of template-controlled aggregation represents the first example of a carbon-free C(80) analogue possessing icosahedral symmetry.

Structure and bonding in three-coordinate N-heterocyclic carbene adducts of iron(II) bis(trimethylsilyl)amide

The molecular structures, chemical bonding and magnetochemistry of the three-coordinate iron(II) NHC complexes [(NHC)Fe{N(SiMe(3))(2)}(2)] (NHC = IPr, 2; NHC = IMes, 3) are reported.

Synthesis, structures and properties of nickel(II) and cobalt(II) metal–organic frameworks based on a flexible tricarboxylate ligand H3TTG and different pyridyl-containing ligands

Along with our recent investigations on Ni and Co coordination frameworks of a flexible tripodal ligand of H3TTG (N,N′,N″-1,3,5-triazine-2,4,6-triyltris-glycine), four new complexes {[Ni(HTTG)(4,4′-bpy)(H2O)3]·(H2O)2}n (1), {[Ni2(HTTG)2(bpe)2(H2O)]·(H2O)6}n (2), {[Co2(HTTG)2(bpe)2(H2O)]·(H2O)6}n (3) and {[Co3(TTG)2(bpe)2]·(H2O)2}n (4) were hydrothermally synthesized through reactions of this ligand with different pyridyl-containing ligands {4,4′-bpy (4,4-bipyridine), bpe [1,2-bi(4-pyridyl)ethane]}, respectively. Due to various coordination modes and conformations of the flexible tricarboxylate ligand and pyridyl-containing coligands, these complexes exhibit structural and dimensional diversity. Complex 1 shows a unique 1D chain bridged by the R22(8) hydrogen bonds between the carboxylate groups, the triazine rings, and hydrogen-bonded networks of the solvent water molecules as well. Complexes 2 and 3 are isomorphous and both exhibit special 2D (8,2)-connected double-layer structures with two kinds of 1D channels constructed by the coordination bonds and hydrogen bonding interactions, respectively. Complex 4 features a 3-D network with scarce (8,3)-connected rutile-related topology with a Schlafli symbol (42,622,7,83)(4,62)2 based on secondary building units (SBUs) of linear cobalt clusters [Co3(CO2)4]2−. Significantly, with increasing flexibility of the pyridyl-containing coligands, these corresponding complexes become more and more complicated. In addition, their physical properties such as thermal, XPRD, and magnetism have also been investigated.

Pentaphosphaferrocen als verknüpfende Einheit in ein‐ und zweidimensionalen Polymeren

Unterschiedliche Produkte mit unterschiedlichen Kupferhalogeniden: Der cyclo-P5-Ligandkomplex [Cp*Fe(5-P5)] 1 bildet bei der Reaktion mit CuBr und CuI zweidimensionale Netzwerke mit 1 als verknupfender Einheit, wahrend mit CuCl ein Koordinationspolymer mit eindimensionaler Kettenstruktur entsteht (siehe Bild).

Structures and Properties of Spherical 90-Vertex Fullerene-Like Nanoballs

By applying the proper stoichiometry of 1:2 to [Cp(R)Fe(eta(5)-P(5))] and CuX (X=Cl, Br) and dilution conditions in mixtures of CH(3)CN and solvents like CH(2)Cl(2), 1,2-Cl(2)C(6)H(4), toluene, and THF, nine spherical giant molecules having the simplified general formula [Cp(R)Fe(eta(5)-P(5))]@[{Cp(R)Fe(eta(5)-P(5))}(12){CuX}(25)(CH(3)CN)(10)] (Cp(R)=eta(5)-C(5)Me(5) (Cp*); eta(5)-C(5)Me(4)Et (Cp(Et)); X=Cl, Br) have been synthesized and structurally characterized. The products consist of 90-vertex frameworks consisting of non-carbon atoms and forming fullerene-like structural motifs. Besides the mostly neutral products, some charged derivatives have been isolated. These spherical giant molecules show an outer diameter of 2.24 (X=Cl) to 2.26 nm (X=Br) and have inner cavities of 1.28 (X=Cl) and 1.20 nm (X=Br) in size. In most instances the inner voids of these nanoballs encapsulate one molecule of [Cp*Fe(eta(5)-P(5))], which reveals preferred orientations of pi-pi stacking between the cyclo-P(5) rings of the guest and those of the host molecules. Moreover, pi-pi and sigma-pi interactions are also found in the packing motifs of the balls in the crystal lattice. Electrochemical investigations of these soluble molecules reveal one irreversible multi-electron oxidation at E(p)=0.615 V and two reduction steps (-1.10 and -2.0 V), the first of which corresponds to about 12 electrons. Density functional calculations reveal that during oxidation and reduction the electrons are withdrawn or added to the surface of the spherical nanomolecules, and no Cu(2+) species are involved.

P2-Ligand Complexes as Building Blocks for the Formation of One-Dimensional Polymers

Bridging coordination of Mo2P2 complexes between metal centers is a prerequisite for the formation of a one-dimensional polymer. The choice of counterion also has a deciding role in determining the polymer structure: while the complex [Cp2Mo2(CO)4(,2-P2)] (1; Cp=C5H5) with AgNO3 forms a zigzag polymer chain, with CuBr 1 forms a linear coordination polymer (see structure).