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An AgI dimer capped with labile organometallic diphosphorus ligands [Cp2Mo2(CO)4(η2‐P2)] (Cp=C5H5) acts as a highly pre‐organized molecular precursor to direct the construction of 1D or 2D, and 3D organometallic–organic hybrid coordination polymers upon reaction with ditopic pyridine‐based linkers. The formation of the supramolecular aggregates can be controlled by the stoichiometry of the organic molecules, and the mechanism is supported by DFT calculations.

A detailed method for the preparation of [Cp''2 Zr(η1:1 -P4 )] (1) is presented. The coordination behavior of 1 towards Lewis acidic transition metal complexes of tungsten, manganese, and iron, respectively, and main group compounds (AlMe3 , AlEt3 ) was investigated in detail by computational and experimental studies. In doing so, a series of unprecedented complexes with different coordination modes and multiple coordination numbers of the tetraphosphabicyclo[1.1.0]butane framework were synthesized. All products, as well as the starting materials, were comprehensively characterized by NMR spectroscopy, mass spectrometry, elemental analysis, and single crystal X-ray structural analysis.

Die cyclo-P4-Komplexe [CpRTa(CO)2(η4-P4)] (CpR: Cp′′=1,3-C5H3tBu2, Cp′′′=1,2,4-C5H2tBu3) erweisen sich als pradestiniert zur Bildung von hohlen spharischen Supramolekulen mit nichtklassischer Fulleren-artiger Topologie. Die resultierenden Aggregate, die mittels CuX (X=Cl, Br) aufgebaut werden, zeigen ein hochsymmetrisches 32er-Gerust, das ausschlieslich aus vier- und sechsgliedrigen Ringen aufgebaut ist. In einigen Supramolekulen ist der innere Hohlraum durch zusatzliche CuX-Einheiten besetzt. Bei Verwendung von CuI werden zwei unterschiedliche Supramolekule mit Erdnuss- oder Birnen-formigen Gerusten und 2–2.5 nm Ausendurchmesser isoliert. Weiterhin sind die spharischen Supramolekule mit Cp′′′-substituierten Tantalkomplexen in CH2Cl2 loslich. NMR-spektroskopische Untersuchungen in Losung zeigen die Bildung von isomeren Supramolekulen infolge der sterischen Hinderung durch die dritte tBu-Gruppe des Cp′′′-Liganden. Zusatzlich wird ein 2D-Koordinationspolymer erhalten und strukturell charakterisiert.

The cyclo-P4 complexes [CpRTa(CO)2(η4-P4)] (CpR: Cp′′=1,3-C5H3tBu2, Cp′′′=1,2,4-C5H2tBu3) turned out to be predestined for the formation of hollow spherical supramolecules with non-classical fullerene-like topology. The resulting assemblies constructed with CuX (X=Cl, Br) showed a highly symmetric 32-vertex core of solely four- and six-membered rings. In some supramolecules, the inner cavity was occupied by an additional CuX unit. On the other hand, using CuI, two different supramolecules with either peanut- or pear-like shapes and outer diameters in the range of 2–2.5 nm were isolated. Furthermore, the spherical supramolecules containing Cp′′′ ligands at tantalum are soluble in CH2Cl2. NMR spectroscopic investigations in solution revealed the formation of isomeric supramolecules owing to the steric hindrance caused by the third tBu group on the Cp′′′ ligand. In addition, a 2D coordination polymer was obtained and structurally characterized.

A detailed method for the preparation of [Cp''

The cyclo‐P4 complexes [CpRTa(CO)2(η4‐P4)] (CpR: Cp′′=1,3‐C5H3tBu2, Cp′′′=1,2,4‐C5H2tBu3) turned out to be predestined for the formation of hollow spherical supramolecules with non‐classical fullerene‐like topology. The resulting assemblies constructed with CuX (X=Cl, Br) showed a highly symmetric 32‐vertex core of solely four‐ and six‐membered rings. In some supramolecules, the inner cavity was occupied by an additional CuX unit. On the other hand, using CuI, two different supramolecules with either peanut‐ or pear‐like shapes and outer diameters in the range of 2–2.5 nm were isolated. Furthermore, the spherical supramolecules containing Cp′′′ ligands at tantalum are soluble in CH2Cl2. NMR spectroscopic investigations in solution revealed the formation of isomeric supramolecules owing to the steric hindrance caused by the third tBu group on the Cp′′′ ligand. In addition, a 2D coordination polymer was obtained and structurally characterized.

The reaction of realgar with [Cp′2MH3] in boiling toluene gave [Cp′2M2As2S6] (Cp′ = t-BuC5H4; M = Nb: 1; Ta: 2), while [Cp2WH2] (Cp = C5H5) reacted with As4S4 to give [Cp2W(H)(η1-As5S2)] (6). The structures were determined by X-ray crystallography. Compounds 1 and 2 are dimers in which two Cp′M units are symmetrically bridged by a μ,η2:2-AsS3 ligand, a sulfide ligand and a heteroallylic μ,η2:2-AsS2 ligand. The structure of 6 belongs to the type of bent metallocenes in which tungsten is surrounded tetrahedrally by two Cp ligands, a crystallographically found hydride atom and the new As5S2 cage. The reaction of 1 with W(CO)5THF gave [Cp′2Nb2As2S6·W(CO)5] (3) and [Cp′2Nb2As2S6W(CO)3·W(CO)5] (4). Compound 3 is a monoadduct of 1 bearing the W(CO)5 fragment at the As atom of the AsS3 ligand. The structure of 4 contains a distorted cubane-like Nb2WS4As cluster with an integrated W(CO)3 unit. A similar cluster 5 containing a CuI fragment instead of W(CO)3 was prepared from 1 and CuI. The structure is completed by an attached As4S3 cage, the As3 basis of which is oriented towards iodide. Electrochemical investigations of 1, 3, and 4 shows for each compound quasi-reversible one-electron reductions with E1/2 = −0.73 V (1), −0.55 V (3) and −0.67 V (4), respectively.

Slow diffusion reactions of the pentaphosphaferrocene [Cp*Fe(η(5)-P(5))] (Cp*=η(5)-C(5)Me(5) (1)) with CuX (X=Cl, Br, I) in different stoichiometric ratios and solvent mixtures result in the formation of one- and two-dimensional polymeric compounds 2-6 with molecular formula [{Cu(μ-X)}{Cp*Fe(μ(3),η(5):η(1):η(1)-P(5))}](n) (X=Cl (2a), I (2'c)), [{Cu(μ-I)}{Cp*Fe(μ(3),η(5):η(1):η(1)-P(5))}](n) (3), [{CuX}{Cp*Fe(μ(4),η(5):η(1):η(1):η(1)-P(5))}](n) (X=Cl (4a), Br (4b), I (4c), Br (4'b), I (4'c)), [{Cu(3)(μ-I)(2)(μ(3)-I)}{Cp*Fe(μ(5),η(5):η(1):η(1):η(1):η(1)-P(5))}](n) (5) and [{Cu(4)(μ-X)(4)(CH(3)CN)}{Cp*Fe(μ(7),η(5):η(2):η(1):η(1):η(1):η(1):η(1)-P(5))}](n) (X=Cl (6a), Br (6b)), respectively. The polymeric compounds have been characterised by single-crystal X-ray diffraction analyses and, for selected examples, by magic angle spinning (MAS) NMR spectroscopy. The solid-state structures demonstrate the versatile coordination modes of the cyclo-P(5) ligand of 1, extending from two to five coordinating phosphorus atoms in either σ or σ-and-π fashion. In compounds 2a, 2'c and 3, two phosphorus atoms of 1 coordinate to copper atoms in a 1,2 coordination mode (2a, 2'c) and an unprecedented 1,3 coordination mode (3) to form one-dimensional polymers. Compounds 4a-c, 4'b, 4'c and 5 represent two-dimensional coordination polymers. In compounds 4, three phosphorus atoms coordinate to copper atoms in a 1,2,4 coordination mode, whereas in 5 the cyclo-P(5) ligand binds in an unprecedented 1,2,3,4 coordination mode. The crystal structures of 6a,b display a tilted tube, in which all P atoms of the cyclo-P(5) ligand are coordinated to copper atoms in σ- and π-bonding modes.

The synthesis and characterization of hybrid polymers combining organic P,P′ (dppe) or N,N′ (pyrazine) ligands and inorganic donors (P4S3) as cross-linkers between copper(I) halide aggregates is described. As a simple model system the reaction of a mixture of P4S3, PEt3, and CuX (X = Cl, Br, I) was studied. According to X-ray diffraction analysis, pseudotetrahedral monomers [CuX(PEt3)2(P4S3)] (1–3) were formed, in which P4S3 coordinates through the apical phosphorus atom. Layering a mixture of P4S3, Ph2PCH2CH2PPh2 (dppe), and toluene with CuCl in MeCN under diffusion conditions gives 1D-[CuCl(dppe)(MeCN)] (6), which contains (Cu2Cl2)2(μ-dppe)2 clusters linked by another dppe ligand. The analogous reaction with CuI gives 1D-[CuI(P4S3)(dppe)] (7), which is built up of alternating trans-(Cu2I2)(P4S3)2 units and dppe linkers. Hybrid polymers 2D-[CuX(P4S3)(dppe)] [X = Br (8), I (9)] are formed if CH2Cl2 is used instead of toluene. The 2D structures of 8 and 9 may be derived from that of 7 by connecting neighboring (CuX)(dppe) strands with pairs of inversely coordinated P4S3 cages. Replacement of dppe by pyrazine (pyz) yields 3D-[(CuCl)4(P4S3)2(pyz)] (10) and 3D-[(CuBr)3(P4S3)(pyz)] (12), respectively. The structure of 10 comprises a 3D network composed of alternating, linked 2D-[(CuCl)2(P4S3)] and 2D-[CuCl(pyz)] layers. The structure of 12 contains cradles built from opposing (CuBr)6 rings and pairwise pyz and P4S3 bridges. These cradles are organized into a 3D framework by condensation of the (CuBr)6 rings, and the layers formed are linked by additional pyz molecules. The resulting voids are occupied by toluene molecules. The behavior of P4S3 and P,P′ or N,N′ ligands as competitive building blocks is also expressed by the formation of binary P4S3/CuX or pyz/CuX polymers.

A series of dinuclear halide bridged copper(I) complexes with a central [Cu2(μ-X)2] diamond core (X = Cl, Br and I) and substituted bis(imino)acenaphthene (BIAN) ligands acting as strong π-acceptor subunits was prepared and characterized by elemental analysis, X-ray crystallography and various spectroscopic techniques. In the visible spectral range, the electronic spectra of these deeply colored air-stable compounds are dominated by low-lying charge transfer (CT) transitions. The corresponding broad absorption bands display a bathochromic shift and a decreasing amount of negative solvatochromism in the series X = Cl, Br and I. At the same time, the distance between the two metals becomes shorter and reaches the range of cuprophilic interactions. These systematic trends are interpreted as a decreasing amount of charge transfer character and a more pronounced delocalization between the two copper centers within in the same series.

The formation of coordination polymers (CuCl)P 4 Se 3 ( 1 ), (CuBr) 3 (P 4 Se 3 ) 2 ( 2 ), (CuI) 3 (P 4 Se 3 ) 2 ( 3 ) and (CuI)P 4 Se 3 ( 4 ), from solutions of copper(I) halides and P 4 Se 3 by diffusion methods has been studied. The new compounds were characterized by X-ray crystallography, solid-state 31 P MAS NMR and Raman spectroscopy. Theoretical studies on the DFT level in the crystalline phase allowed the unequivocal assignment of the recorded Raman shifts between 200 and 480 cm −1 . The structure of 1 consists of a 2D network of castellated [CuCl] n chains and bidentate P 4 Se 3 molecules. The 3D network of 2 comprises [CuBr] n chains, which are linked by tridentate P 4 Se 3 molecules. Compound 3 is a three-dimensional polymer composed of four-membered (CuI) 2 rings and castellated [CuI] n chains, which are linked by tridentate P 4 Se 3 molecules involving two basal and the apical P atoms. Thermal conversion of 1 at 230 °C gives (CuCl) 3 (P 4 Se 3 ) 2 ( 5 ), which is isostructural with 2 . The thermal conversion of (CuI) 3 P 4 S 3 , which was studied for comparison gave at 371 °C (CuI) 3 P 4 S 4 , Cu 3 PS 4 and small amounts of Cu 6 PS 5 I.

The diastereomers (RFe,RC)/(SFe,RC)-[CpFe(Prophos)NCMe]X (X = I, PF6), 5:95, differing only in the metal configuration, were prepared from (RFe,RC)/(SFe,RC)-[CpFe(Prophos)I] (95:5) in acetonitrile ...

The coordination behavior of 1,2,4-triphosphaferrocenes [FeCpR(η5-P3C2tBu2)] [CpR = Cp (1), Cp″′ = η5-C5H2tBu3 (3)] towards CuI halides is significantly influenced by the substitution pattern of the cyclopentadienyl ring attached to the iron atom. The reaction of the Cp derivative 1 with CuBr in a 1:1 stoichiometry leads to the dimeric complex [{FeCp(η5:η1:η1-P3C2tBu2)}{μ-CuBr(MeCN)}]2 (5b), in which two 1,2,4-triphosphaferrocenes are linked by two CuBr units. By using a 1:2 stoichiometry, the 1D polymeric compound [{FeCp(η5:η1:η1:η1-P3C2tBu2)}μ-{(CuBr)3(MeCN)2}]n (6) is formed in which the triphosphaferrocenes are bridged by (CuBr)2{CuBr(MeCN)2} units. Starting from CuI, independent of the stoichiometry, the cage compound [{FeCp(η5:η1:η1-P3C2tBu2)}3{Cu(μ-I)}3{Cu(μ3-I)}3{Cu(NCMe)}(μ6-I)](7) is formed. However, if the bulky Cp″′ derivative 3 is used already in a 1:1 stoichiometry with CuBr, a transformation of the initially five-membered 1,2,4-triphospholyl ring into a four-membered 1,2-diphosphete ligand is observed, which is linked by CuBr moieties forming the dimeric paramagnetic complex [{FeCp″′(η4:η1:η1-P2C2tBu2)}(μ-CuBr)]2 (9). Furthermore, applying a 1:2 stoichiometry between 3 and CuX (X = Br, I) the complete fragmentation of the 1,2,4-triphospholyl ring under mild conditions into a tetraphosphabutadiene ligand is observed. In the formed 1D polymeric complexes [{(FeCp″′)2(μ,η4:η1:η1-P4)}{(μ-CuX)2(MeCN)}]n [X = Br (10a), I (10b)] this ligand represents now the middle deck of the triple-decker sandwich complexes linked by four-membered [(CuX)2(CH3CN)] moieties. Moreover, the reaction of the Cp derivative 1 with the Ag salt of the weakly coordinating anion [Al{OC(CF3)3}]4– leads to the dimeric Ag(CH3CN)-bridged dicationic product [{FeCp(η5-P3C2tBu2)}Ag(MeCN)]2[Al{OC(CF3)3}4]2 (11).

Reaction of solutions of [ Cp ∗ Cp ∗ = η 5 -C 5 Me 5 ) in CH 2 Cl 2 with solutions of CuHal (Hal = Cl, Br, I) in CH 3 CN gave after slow diffusion the novel coordination polymers [ Cp 2 ∗ Mo 2 P 2 S 3 (CuCl) 4 ] ( 2 ), [ Cp 2 ∗ Mo 2 P 2 S 3 (CuBr) 3 ] ( 3 ) and [ Cp 2 ∗ Mo 2 P 2 S 3 (CuI) 3 ] ( 4 ). The products were characterized by elemental analysis, 31 P magic angle spinning (MAS) NMR spectroscopy and single-crystal X-ray crystallography. The solid-state structures of 2 and 3 are composed of two-dimensional polymeric networks, whereas that of 4 contains parallel stacks of one-dimensional ribbons. In all cases the planar cyclo -P 2 S 3 middle deck of the organometallic building block 1 provides one or two P atoms of the PS dumbbells along with the singly bridging sulfur atom as coordination sites for the various copper halide subunits. The assignment of P atoms follows from the correlation of 31 P MAS NMR spectra with X-ray crystallographic data. In all compounds the distribution of main group atoms in the cyclo -P 2 S 3 middle deck is different from that previously found in the starting material 1 .

The synthesis, structure, photophysics, and spectroscopic characterization of two novel organometallic rhodium and rhenium multichromophore photosensitizers carrying a central 2,2′-bipyridyl acceptor moiety are reported. Due to the presence of rigid phenylethynyl substituents in their 5,5′-position acting as intramolecular antenna groups, these compounds display perturbed excited state properties and a modified luminescence behaviour compared to the unsubstituted parent systems. The rhodium derivative is characterized by a weak blue–green intraligand (IL) phosphorescence occurring only at low temperatures. In the rhenium complex both a blue–green ligand-based luminescence and a red phosphorescence of metal-to-ligand charge transfer (MLCT) origin is observed at room temperature in solution. In rigid 77 K matrix the lowest-lying excited state levels approximate in energy and a structured luminescence band occurs which is ascribed to a ligand phosphorescence with admixed MLCT character.

1-[2-(Dialkylamino)ethyl]-3-methylimidazolium salts (alkyl = Me (1a), i-Pr (1b)) have been prepared and used as precursors for the synthesis of the corresponding [(NHC)2Ag][AgCl2] complexes (NHC = N-heterocyclic carbene, Me (2a), i-Pr (2b)). Upon treatment of 2a with HBF4, crystals of the unprecedented, NHC-stabilized silver cluster [(NHC)4Ag10Cl10] (5) were obtained and characterized by X-ray diffraction. The crystal structure reveals that the carbene carbon atom exists in the rare μ2-coordination pattern, bridging two Ag(I) atoms with further stabilization of the cluster by numerous argentophilic interactions and a coordination of the amino nitrogen donor to one of the silver atoms. Transmetalation of 2a,b with (R2S)AuCl leads to the respective Au(I) complexes 3a,b, which are further oxidized with Br2 to (NHC)AuBr2Cl (4a,b). In red crystals of 4a the gold atom is coordinated in the unusual square-pyramidal geometry with the amine nitrogen atom in the axial position. Upon dissolution in wet organic solve...

The compounds [CpFe(Prophos)Cl] and [CpFe(Prophos)I] were prepared in photochemical reactions of [CpFe(CO)2Cl] and [CpFe(CO)2I] with (R)-Prophos. They consist of pairs of RFe,RC and SFe,RC diastereomers which only differ in the configuration at the metal atom. The diastereomerically pure compounds (SFe,RC)-[CpFe(Prophos)Cl] and (RFe,RC)-[CpFe(Prophos)I], which have the same relative configurations, were isolated. They epimerize via change of the Fe configuration and approach the equilibria (RFe,RC)-/(SFe,RC)-[CpFe(Prophos)Cl] = 5/95 and (RFe,RC)-/(SFe,RC)-[CpFe(Prophos)I] = 95/5 in first-order reactions with half-lives of 43 min at 20 °C and 50 min at 50 °C in C6D6, respectively. The reaction of (RFe,RC)-/(SFe,RC)-[CpFe(Prophos)I] = 95/5 with KCN afforded the cyano complex [CpFe(Prophos)CN] in the diastereomer ratio RFe,RC/SFe,RC = 50/50. Both diastereomers (RFe,RC)- and (SFe,RC)-[CpFe(Prophos)CN] could be isolated diastereomerically pure. The compounds (RFe,RC)- and (SFe,RC)-[CpFe(Prophos)CN] are configu...

The synthesis and spectroscopic characterization of [Cp*2Mo2P2Se3] (1; Cp* = C5Me5) and its use as a molecular building block in the formation of copper(I) halide polymers is described. The reaction of 1 in CH2Cl2 with 2 equiv. of CuBr and CuI in CH3CN under diffusion conditions gave [(Cp*2Mo2P2Se3)2(CuBr)2] (2) and [(Cp*2Mo2P2Se3)(CuX)3(CH3CN)]n (X = I; 3/4), respectively. The structure of 2 is distinguished by a central Cu2Br2 ring coordinated on each side by a tripledecker complex through one of its P atoms. A 2D network is formed by weak interactions between Se atoms of neighboring molecules. Compound [(Cp*2Mo2P2Se3)(CuI)3(CH3CN)]n exists in two isomeric forms 3 and 4. The crystal structure of 3 can be described as a two-dimensional polymer that is formed by ribbons containing looped chains of three Cu2I2 rings and attached [Cp*2Mo2P2Se3] molecules. The structure of 4 contains a ribbon in which tripledecker molecules are linked through their P atoms to (CuI)6 clusters. The ribbons are connected by weak Se···Se interactions. The reaction of a mixture of 1 and P4Se3 with CuI gave [(Cp*2Mo2P2Se3)(P4Se3)(CuI)2]n. The crystal structure analysis of 5 reveals a new type of organometallic–inorganic framework in which 1 and P4Se3 are linked by Cu2I2 rings.

The reaction of the 1,2,4-triphosphaferrocene [Cp*Fe(η5-P3C2tBu2)] (1) with CuX (X = Cl, Br, I) in a 1:1 stoichiometric ratio leads to the formation of the oligomeric compounds [{Cu(μ-X)}6(μ6-X)Cu(MeCN)3{μ,η2-(Cp*Fe(η5-P3C2tBu2))}2{μ3,η3-(Cp*Fe(η5-P3C2tBu2))}] (X = Cl (2), Br (3)) and [{Cu(μ-I)}3{Cu(μ3-I)}3Cu(μ6-I){μ,η2-(Cp*Fe(η5-P3C2tBu2))}3{η1-(Cp*Fe(η5-P3C2tBu2))}] (4) revealing Cu(I) halide cages surrounded by 1,2,4-triphosphaferrocene moieties. The reaction of [Cp*Fe(η5-P3C2tBu2)] with CuI in a 1:4 stoichiometry leads to the formation of the two-dimensional polymer [{Cu(μ-I)}4{Cu(μ3-I)(MeCN)}2{μ3,η3-(Cp*Fe(P3C2tBu2))}]n (5). The oligomeric compounds show dynamic behavior in solution monitored by 31P NMR spectroscopy. All compounds are additionally characterized by single crystal X-ray diffraction.

This work describes the synthesis, crystal structure, and detailed photophysical studies of [n-Bu(4)N][Pt(4,6-dFppy)(CN)(2)] (n-Bu = n-butyl, 4,6-dFppy = (4',6'-difluorophenyl)pyridinate). The material can easily be prepared in high yield and purity by the reaction of [Pt(4,6-dFppy)(H-4,6-dFppy)Cl], [n-Bu(4)N]Cl, and KCN in CH(2)Cl(2). Because of the bulky counterion [n-Bu(4)N](+), Pt-Pt interactions, which frequently lead to aggregate formation, are suppressed in the solid state. Thus, monomer emission is observed. The phosphorescence quantum yield of the neat powder amounts to phi(PL) = 60% at ambient temperature and decays with 19 micros. In tetrahydrofuran (THF) solution, on the other hand, the emission decay time is with 0.26 micros distinctly shorter, and the quantum yield is very low. By means of emission decay time studies in frozen THF and investigations of the highly resolved single crystal emission at 1.2 K, we can assign the emitting T(1) state of the compound as being largely of ligand centered ((3)LC, (3)pi pi*) character. The observed differences of the emission properties of the neat powder compared to the fluid solution are rationalized with an energy stabilization of quenching dd* states in solution because of molecular distortions and/or bond elongations.

A series of pseudo-tetrahedral copper(I) complexes carrying bis(imino)acenaphthene (BIAN) ligands as acceptor subunits and various phosphane derivatives was prepared and characterized by elemental analysis, X-ray crystallography and spectroscopic techniques. The electronic spectra of the compounds are dominated by low-lying metal-to-ligand charge transfer (MLCT) transitions which could be systematically modified by different substituent patterns at the diimine acceptor subunit and by variations of the electron donating properties and bite angles of the phosphane moiety. A qualitative model based on frontier-orbital overlap arguments is introduced to describe the observed variations in optical spectra, excited state energies, solvatochromic behaviour, charge transfer character, and extent of electronic coupling following moderate changes in orbital mixing. Due to their readily tuneable properties and the potential of the BIAN ligands to reversibly store up to four redox equivalents, these systems are of considerable interest for the development of novel multi-electron transfer photosensitizers which are based on the abundant and environmentally benign transition metal copper.

The PH3-containing complex [(CO)4W(PH3)2] (1) is synthesized in good yields by the “one-pot” reaction of [(CO)4W(nbd)] (nbd = norbonadiene) with P(SiMe3)3 and subsequent methanolysis of the reaction mixture. The further reaction of [(CO)4W(PH3)2] with [Co2(CO)8] results in three novel cobalt clusters, [Co8(CO)18(μ6-P)2(μ-CO)] (2), [Co10(CO)18(μ7-P)2(μ-CO)6] (3), and [[Co3(CO)8{μ4-PW(CO)5}][(μ4-P)Co3(CO)9]] (4). All products have been comprehensively characterized including X-ray diffraction.

The formation of coordination polymers from copper(I) bromide and P4S3, a potentially tetradentate P-donor bridging ligand, was studied. Whereas (P4S3)3(CuBr)7 (1) formed in excellent yield, (P4S3)(CuBr)3 (2) and (P4S3)(CuBr) (3) crystallized as mixtures. The new compounds were characterized by X-ray crystallography and solid-state 31P MAS NMR spectroscopy. The structure of 1 consists of a 3D network of cylindrical (CuBr)n columns, castellated (CuBr)n chains and diatomic CuBr units. These building blocks are linked by tetradentate P4S3 molecules. The structure of 2 comprises undulated (CuBr)n layers, which are intra- and interlayer linked by tridentate P4S3 molecules. Compound 3 is a one-dimensional polymer composed of four-membered Cu2Br2 rings, which are bridged by the P3 bases of two P4S3 molecules.

The formation of a new type of organometallic-inorganic hybrid coordination polymer from P 4 S 3 ·W(CO) 5 (1) and CuI has been studied. The structure of {P 4 S 3 ·W(CO) 5 }(CuI) (3) has been verified by the combination of spectroscopic (IR, Raman, 31 P MAS NMR) and X-ray diffraction methods. Theoretical studies of β-P 4 S 3 , P 4 S 3 ·W(CO) 5 (1), 1D-(P 4 S 3 )(CuI) (2), and 3D-(P 4 S 3 )(CuI) 3 (4), which may be considered as potential building blocks of 3, were carried out on the DFT level in the crystalline phase. The comparison of calculated and measured vibration modes of the P 4 S 3 cage allows the unequivocal assignment of the recorded Raman shifts between 200 and 480 cm -1 and the determination of the degree of integration of P 4 S 3 within the one-dimensional stacks of 2 or copper iodide networks of 3 and 4.

The palladium-catalyzed aerobic oxidation of alkenes and especially styrenes (Wacker oxidation) by using chiral pseudo C(2)-symmetrical bis(isonitrile) ligands in the absence of further cocatalysts gives rise to methyl ketones in a highly chemoselective manner. The palladium bis(isonitrile) catalyst was characterized by NMR spectroscopy and X-ray structure analysis, revealing a dissymmetric coordination of palladium by the two isonitrile moieties.

This paper reports the synthesis, isomer separation, and X-ray characterization of the compounds (SRu,SC)-/(RRu,SC)-[CpRu(Chairphos)Cl], Chairphos = (S)-1,3-bis(diphenylphosphanyl)butane, and cis-/...

Stepwise opening and final removal of the η1-bound Cp* substituents in the bridged pentelidene complexes [Cp*E{W(CO)5}2] (E=P, As) occurs by the reaction with primary phosphines. Not only novel diphospha- and arsaphosphanorbornenes are obtained, but also diastereomerically pure complexed triphosphines. All reaction steps were monitored by NMR spectroscopy, and compounds structurally characterized.

The hexaphosphaferrocene complex [Fe(η5-P3C2tBu2)2] (1) derived from the corresponding 1,2,4-triphosphospholyl anion reacts with CuX (X = Cl, Br, I) in a 1 : 1 stoichiometry to give the isostructural, one-dimensional polymeric compounds [{Cu(μ3-X)}4{Fe(μ,η5:η1-P3C2tBu2)2}2]n (X = Cl (2), Br (3), I (4)), which display a unique sinusoidal (CuX)n ladder structure. In the reaction with CuI a second one-dimensional polymeric compound [{Cu3(μ-I)(μ3-I)2}(CH3CN){Fe(μ,η5:η1- P3C2tBu2)(μ3,η5:η1-P3C2tBu2)}]n (5) is formed. The reaction of 1 with CuX (X= Cl, Br, I) in a 1 : 2 stoichiometric ratio leads only in the case of CuCl to the formation of the new, oligomeric compound [{Cu(μ3-Cl)}4(CH3CN)2{Fe(μ,η5:η1-P3C2tBu2)2}2] (6), whereas in the case of CuBr and CuI the polymeric compounds 3 and 5 were isolated. The reaction of 1 with Ag[Al{OC(CF3)3}4] in a 1:1 stoichiometric ratio results in the formation of [Ag{Fe(μ,η5:η1-P3C2tBu2)2}2][Al{OC(CF3)3}4] (7), which shows dynamic behaviour in solution

The thermal reaction of trans-1-methyl-2,3-diphenylaziridine (trans-1a) with aromatic and cycloaliphatic thioketones 2 in boiling toluene yielded the corresponding cis-2,4-diphenyl-1,3-thiazolidines cis-4via conrotatory ring opening of trans-1a and a concerted [2+3]-cycloaddition of the intermediate (E,E)-configured azomethine ylide 3a (Scheme 1). The analogous reaction of cis-1a with dimethyl acetylenedicarboxylate (5) gave dimethyl trans-2,5-dihydro-1-methyl-2,5-diphenylpyrrole-3,4-dicarboxylate (trans-6) in accord with orbital-symmetry-controlled reactions (Scheme 2). On the other hand, the reactions of cis-1a and trans-1a with dimethyl dicyanofumarate (7a), as well as that of cis-1a and dimethyl dicyanomaleate (7b), led to mixtures of the same two stereoisomeric dimethyl 3,4-dicyano-1-methyl-2,5-diphenylpyrrolidine-3,4-dicarboxylates 8a and 8b (Scheme 3). This result has to be explained via a stepwise reaction mechanism, in which the intermediate zwitterions 11a and 11b equilibrate (Scheme 6). In contrast, cis-1,2,3-triphenylaziridine (cis-1b) and 7a gave only one stereoisomeric pyrrolidine-3,4-dicarboxylate 10, with the configuration expected on the basis of orbital-symmetry control, i.e., via concerted reaction steps (Scheme 10). The configuration of 8a and 10, as well as that of a derivative of 8b, were established by X-ray crystallography.

The molecular structure of [Cp*2Mo2P2S3] (1; Cp* = η5-C5Me5) has been reinvestigated. In DFT studies a series of various positional isomers A−E have been calculated for the model complex [(C5H5)2Mo2P2S3]. The energetically favored isomer [Cp*2Mo2(μ,η2:2-PS)2(μ-S)] (1B) reacts with W(CO)5THF to give [Cp*2Mo2P2S3·W(CO)5] (2). X-ray diffraction analysis of 2 confirms the presence of two η2:2-PS dumbbells and one singly bridging sulfur ligand, the W(CO)5 fragment being coordinated at one of the P atoms. Arrangement B is also found in the structure of the diadduct [Cp°2Mo2P2S3{W(CO)5}2] (3; Cp° = t-BuMe2C5H2), which is more stable than its Cp* analogue. 31P solid-state MAS NMR spectroscopic studies of 1 and 2 confirm the existence of only one isomer, but reveal disorder phenomena in the solid state within the cyclo-P2S3 middle deck. Addition of excess W(CO)5THF to 1 proceeds via elusive [Cp*2Mo2P2S3{W(CO)5}2] to give the cluster [{Cp*2Mo2W(CO)3(μ2,η2:2-PS)(μ3,η1:1:2-PS)(μ3-S)}{W(CO)5}2] (5). The molecular stru...

Ru(CH═CHFc)Cl(CO)(PiPr3)2 (Fc = ferrocenyl, (η5-C5H4)Fe(η5-C5H5)), 1, has been prepared by hydroruthenation of ethynylferrocene and characterized by NMR, IR, ESI-MS, and Moessbauer spectroscopy and by X-ray crystallography. Complex 1 features conjoined ferrocene and (vinyl)ruthenium redox sites and undergoes two consecutive reversible oxidations. Pure samples of crystalline, monooxidized 1•+ have been prepared by chemical oxidation of 1 with the ferrocenium ion. Structural comparison with 1 reveals an increase of Fe−C and Fe−Cpcentr. bond lengths and ring tilting of the Cp decks, as is typical of ferrocenium ions, but also a discernible lengthening of the Ru−C(CO) and Ru−P bonds and a shortening of the Ru−C(vinyl) bond upon oxidation. This supports the general idea of charge delocalization over both redox sites in 1•+. Band shifts of the charge-sensitive IR labels (ν(CO) for Ru, ν(C−H, Cp) for Fc), the rather small g-anisotropy in the ESR spectrum of 1•+, and the results of quantum chemical calculations i...

Mixed cobalt(III) complexes with diethylenetriamine (Dien) and a tridentate anion of L-ornithine (Orn) [Co(Dien)(His)](ClO4)2 · 0.5 H2O or DL-histidine (His) [Co(Dien)(Orn)](ClO4)2 are synthesized. According to the X-ray diffraction studies, the secondary N atom of diethylenetriamine is trans to the donor N atom of the side chain of the amino acid. Organometallic products of photodecarboxylation of the complexes are isolated by ion exchange chromatography. The electronic absorption spectra indicate that the products contain three-membered Co-C-N rings.

Short peptidomimetics with stable secondary structures in solution are of interest for applications in chemistry, biology, and medicine. One way to rigidify the backbone of a peptide is the use of cyclic C(alpha)-tetrasubstituted alpha-amino acids (TAAs) like compound 14. The structures resulting from the incorporation of this unnatural amino acid into peptides were investigated. In total, 13 different peptides with a length of up to eight residues and alternating sequences of TAA 14 and (S)- or (R)-valine were synthesized. Their structures were characterized by X-ray diffraction analysis and NMR and CD measurements showing that the all-S-backbone-configured peptides 5 and 6 (SS)(2-3) form right-handed 3(10)-helices, while the all-R-configured peptides 11-13 (RR)(2-4) form left-handed 3(10)-helices in the solid state and solution.

Ruthenium and osmium complexes 2a,b and 3a,b featuring the N-4,6-dioxo-5,5-dibutyl- or the N-4,6-dioxo-5,5-di-(2-propenyl)-1,4,5,6-tetrahydropyrimidin-2-yl-N'(4-ethenylphenyl)-urea ligand dimerize by a self-complementary quadruply hydrogen-bonding donor/donor/acceptor/acceptor (DDAA) motif. We provide evidence that the dimeric structures are maintained in nonpolar solvents and in 0.1 M NBu(4)PF(6)/CH(2)Cl(2) supporting electrolyte solution. All complexes are reversibly oxidized in two consecutive two-electron oxidations (DeltaE(1/2) approximately = 500 mV) without any discernible potential splitting for the oxidation of the individual hydrogen-bridged redox active moieties. IR and UV/vis/NIR spectroelectrochemistry show a one-step conversion of the neutral to the dication without any discernible features of an intermediate monooxidized radical cation. Oxidation-induced IR changes of the NH and CO groups that are involved in hydrogen bonding are restricted to the styryl-bonded urea NH function. IR band assignments are aided by quantum chemical calculations. Our experimental findings clearly show that, at least in the present systems, the ureapyrimidinedione (Upy) DDAA hydrogen-bonding motif does not support electron transfer. The apparent reason is that neither of the hydrogen-bonding functionalities contributes to the occupied frontier levels. This results in nearly degenerate pairs of MOs representing the in-phase and out-of-phase combinations of the individual monomeric building blocks.

The reaction of the 1,2,3-triphosphaferrocene [Cp′′′Fe(η5-P3C2(H)Ph)] (1) with the Lewis acidic complex [PtCl2(PEt3)]2 yields the monosubstituted derivative [Cp′′′Fe(η5-P3C2(H)Ph){PtCl2(PEt3)}] (2), in which the Pt moiety is located at the P atom adjacent to the C(H) group of the cyclo-P3C2 ring. Using an excess of the Pt complex no multiple substitution occurs. In contrast, using [W(CO)5] units as Lewis acids results in mono-, di-, and tricoordination at the cyclo-P3C2 ring. The products, [Cp′′′Fe(η5-P3C2(H)Ph){W(CO)5}n] (n = 1 (3), 2 (4), 3 (5)), have all been spectroscopically characterized, and the substitution patterns of the experimentally found (mono- and disubstituted) isomers are found to be in accordance with the energetically favored derivatives calculated by DFT methods. For these structures the energetically favored rotational conformers have also been calculated. The energetically favored 2,3-coordinated isomer 4b could be crystallized, and its structure and that of the tricoordinated derivative 5 were determined by X-ray diffraction methods.

First examples of the coordination chemistry of the As4S3 cage were obtained from solutions of As4S3·M(CO)5 (M = Cr, W) in CH2Cl2 and CuCln in CH3CN (n = 1) or CH3OH (n = 2) through interdiffusion techniques. The compounds (As4S3)(CuCl)n (1: n = 1; 2: n = 2) exhibit Cu coordination exclusively through the sulfur bridges. The crystal structure of 1 containsa saw-like [CuCl] backbone to which As4S3 cages are alternately fixed on both sides through two of their sulfur atoms. The crystal structure of 2 is built up of sheets, in which As4S3 molecules are connected by folded four-membered Cu2Cl2 rings through all sulfur atoms. Comparative Raman spectra of As4S3 and 1 indicate significant interactions between the cage S atoms and Cu.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)