Peter Brüggeller

University of Innsbruck, Innsbruck, Tyrol, Austria

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Publications (47)122.31 Total impact

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    ABSTRACT: The new high-pressure gallium borate Ga2B3O7(OH) was synthesized in a Walker-type multianvil apparatus under high-pressure/high-temperature conditions of 10.5 GPa and 700 °C. For the system Ga-B-O-H, it is only the second known compound next to Ga9B18O33(OH)15·H3B3O6·H3BO3. The crystal structure of Ga2B3O7(OH) was determined by single-crystal X-ray diffraction data collected at room temperature. Ga2B3O7(OH) crystallizes in the orthorhombic space group Cmce (Z = 8) with the lattice parameters a = 1050.7(2) pm, b = 743.6(2) pm, c = 1077.3(2) pm, and V = 0.8417(3) nm(3). Vibrational spectroscopic methods (Raman and IR) were performed to confirm the presence of the hydroxyl group. Furthermore, the band gap of Ga2B3O7(OH) was estimated via quantum-mechanical density functional theory calculations. These results led to the assumption that our gallium borate could be a suitable substance to split water photocatalytically, which was tested experimentally.
    No preview · Article · Dec 2015 · Inorganic Chemistry
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    ABSTRACT: Dyads for photochemical water splitting often suffer from instability during irradiation with visible light. However, the use of bis(bidentate) phosphines forming a five-membered ring enhances their stability. The coordination of these phosphor based chelates to soft metals like Pd(ii) prolongs the photocatalytic activity to 1000 hours. To avoid contribution to hydrogen production by colloidal metal, a small amount of Hg is added to the reaction mixture. In the course of our investigations, it turned out that colloidal palladium was not able to produce hydrogen under our irradiation conditions. As soon as metallic palladium emerged in our reaction vessels, no further hydrogen production was detected. This is confirmed by the observation that the hydrogen production depends on the kind of ancillary ligands present in the dyads. The first dyads of the type [MI(bpy)2(dppcb)MII(bpy)](4+) are presented (MI = Os, MII = Pd (); MI = Ru, MII = Pd (); MI = Os, MII = Pt (); MI = Ru, MII = Pt ()). In [Os(bpy)2(dppcb)Pd(dppm)](PF6)4 () the ancillary ligand is varied. Furthermore, it is also possible to produce hydrogen in an intermolecular way. Using different bidentate diphosphines instead of a bis(bidentate) tetraphosphine leads to this intermolecular approach, where the chromophore and the water reduction catalyst (WRC) belong now to two molecules. In this case the TON is sensitive to the type of diphosphine, which is only possible if intact molecules act as catalysts and no free palladium(0) is formed.
    Full-text · Article · Nov 2015 · Dalton Transactions
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    ABSTRACT: The synthesis and the photophysics of three dinuclear copper(I) complexes containing bis(bidentate)phosphine ligands are described. The steric constraint imposed by tetrakis(di(2-methoxyphenyl)phosphanyl)cyclobutane) (o-MeO-dppcb) in combination with 2,9-dimethyl-1,10-phenanthroline in one of the complexes leads to interesting photophysical properties. The compound shows an intense emission at room temperature in deoxygenated acetonitrile solution (Φ = 49%) and a long excited-state lifetime (13.8 μs). Interestingly, at low temperature, 77 K, the emission maximum shifts to lower energy, and the excited-state lifetime increases. This observation leads to the conclusion that a mixing between the excited triplet and singlet states is possible and that the degree of mixing and population of state strongly depends on temperature, as the energy difference is quite small. The electroluminescent properties of this compound were therefore tested in light-emitting electrochemical cells (LEECs), proving that the bright emission can also be obtained by electrically driven population of the singlet state.
    Full-text · Article · Oct 2014 · Inorganic Chemistry
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    ABSTRACT: The coordination of Pd(II) to the 1,3-trans- and 2,3-trans-dioxides and the trioxide of cis,trans,cis-1,2,3,4-tetrakis(diphenylphosphino)cyclobutane gave two dinuclear Pd(II) complexes, which are structural isomers, and a mononuclear complex, respectively. The latter complexes proved to be suitable precatalysts for the oligomerization of ethylene to linear α-olefins (98% selectivity). The different catalytic activity of the structural isomers was shown to depend on the dynamic behavior of the molecular structure.
    No preview · Article · Jul 2014 · Organometallics
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    ABSTRACT: The bis(bidentate) phosphane cis,trans,cis-1,2,3,4-tetrakis(diphenylphosphanyl)cyclobutane (dppcb) has been used for the synthesis of supramolecular complexes, so-called dyads and triads. Depending on the monometallic precursor compound [Ru(bpy)2(dppcb)](PF6)2 or [Ru(bpy)2(cis-dppcbO2)](PF6)2 [bpy = 2,2′-bipyridine, cis-dppcbO2 = cis,trans,cis-1,2-bis(diphenylphosphanoyl)-3,4-bis(diphenylphosphanyl)cyclobutane], [Ru(bpy)2(dppcb)NiBr2](PF6)2 (1) or ΔΛ/ΛΔ-[{Ru(bpy)2(cis-dppcbO2)}2NiBr](PF6)5 (2) is exclusively formed in good yield by reaction with [NiBr2(DME)] (DME = dimethoxyethane). The versatile coordination behaviour of dppcb compared with that of cis-dppcbO2 is confirmed by cis,trans,cis-2,3-bis(diphenylphosphanoyl)-1,4-bis(diphenylphosphanyl)cyclobutane (2,3-trans-dppcbO2, 4). Although two dppcb ligands coordinated simultaneously to a PdII centre cannot produce a square-planar PdP4 core, the reaction of two equivalents of 4 with [Pd(CH3CN)4](BF4)2 exclusively leads to meso-(MMMP/MPPP)-[Pd(2,3-trans-dppcbO2-P,P′)2](BF4)2 (3). This means that trans configurations of coordinating 2,3-trans-dppcbO2 with respect to the cyclobutane rings allow the formation of this PdP4 moiety. However, in the case of 4 it is also possible to obtain [PdCl2(2,3-trans-dppcbO2-P,P′)] (5) in excellent yield by using [PdCl2(COD)] (COD = cyclooctadiene). In 5, only one ligand 4 is attached to the PdII centre, and a trans configuration of 4 within the five-membered chelate ring can again be seen. All solid-state structures 1–5 have been determined by single-crystal X-ray structure analysis. The corresponding solution structures are in agreement with these solid-state structures and have been authenticated by multinuclear NMR spectroscopy, FAB and MALDI-TOF-MS measurements, UV/Vis spectroscopy and cyclic voltammetry. In the case of 2, the emission and lifetime properties of the excited state indicate that triads such as 2 could be suitable catalysts for the reductive part of water splitting.
    No preview · Article · Oct 2013 · European Journal of Inorganic Chemistry
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    ABSTRACT: For the first time oxidative quenching of OsP2N4 chromophores by reactive PtII or PdII sites containing cis, trans, cis-1,2,3,4-tetrakis(diphenylphosphino)cyclobutane (dppcb) is directly observed despite the presence of a saturated cyclobutane backbone "bridge". This dramatic effect is measured as a sudden temperature-dependent onset of a reduction in phosphorescence lifetime in [Os(bpy)2(dppcb)MCl2](SbF6)2 (M = Pt, 1; Pd, 2). The appearance of this additional energy release is not detectable in [Os(bpy)2(dppcbO2)](PF6)2 (3), where dppcbO2 is cis, trans, cis-1,2-bis(diphenylphosphinoyl)-3,4-bis(diphenylphosphino)cyclobutane. Obviously, the square-planar metal centers in 1 and 2 are responsible for this effect. In line with these observations, the emission quantum yields at room temperature for 1 and 2 are drastically reduced compared with 3. Since this luminescence quenching implies strong intramolecular interaction between the OsII excited states and the acceptor sites and depends on the metal⋯metal distances, also the single crystal X-ray structures of 1-3 are given.
    Preview · Article · Sep 2012 · Inorganic Chemistry Communications
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    ABSTRACT: An in situ generated dinuclear palladium hydride complex bearing cis,trans,cis-1,2,3,4-tetrakis(diphenylphosphanyl)cyclobutane catalyzed the hydromethoxycarbonylation of terminal alkynes, giving the corresponding branched α,β-unsaturated ester (A) with high regioselectivity.
    No preview · Article · Jun 2012 · Organometallics
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    ABSTRACT: The P-O ligand 3-(di(2-methoxyphenyl)phosphanyl)propionic acid (HL) was synthesized by a microwave-assisted reaction of a secondary phosphane. The coordination of HL to Pt(II) yielded the neutral mononuclear complex trans-[PtCl(κ(2)-P,O-L)(κ-P-HL)] (1), while the reaction of PdClMe(η(4)-COD) (COD = 1,4-cyclooctadiene) with HL in the presence of NEt(3) gave the anionic Pd(II) compound of the formula (HNEt(3))[PdClMe(κ(2)-P,O-L)] (2). Upon crystallization of the latter compound the neutral chloride-bridged dimetallic compound cis-[Pd(μ-Cl)Me(HL)](2) (3) was obtained. HL, 1 and 3·CH(2)Cl(2) have been characterized by single crystal X-ray structure analyses.
    Preview · Article · Sep 2011 · Inorganica Chimica Acta
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    ABSTRACT: The bis(bidentate) phosphine cis,trans,cis-1,2,3,4-tetrakis(diphenylphosphino)cyclobutane (dppcb) has been used for the synthesis of a series of novel heterodimetallic complexes starting from [Ru(bpy)(2)(dppcb)]X(2) (1; X = PF(6), SbF(6)), so-called dyads, showing surprising photochemical reactivity. They consist of [Ru(bpy)(2)](2+)"antenna" sites absorbing light combined with reactive square-planar metal centres. Thus, irradiating [Ru(bpy)(2)(dppcb)MCl(2)]X(2) (M = Pt, 2; Pd, 3; X = PF(6), SbF(6)) dissolved in CH(3)CN with visible light, produces the unique heterodimetallic compounds [Ru(bpy)(CH(3)CN)(2)(dppcb)MCl(2)]X(2) (M = Pt, 7; Pd, 8; X = PF(6), SbF(6)). In an analogous reaction the separable diastereoisomers (ΔΛ/ΛΔ)- and (ΔΔ/ΛΛ)-[Ru(bpy)(2)(dppcb)Os(bpy)(2)](PF(6))(4) (5/6) lead to [Ru(bpy)(CH(3)CN)(2)(dppcb)Os(bpy)(2)](PF(6))(4) (9), where only the RuP(2)N(4) moiety of 5/6 is photochemically reactive. By contrast, in the case of [Ru(bpy)(2)(dppcb)NiCl(2)]X(2) (4; X = PF(6), SbF(6)) no clean photoreaction is observed. Interestingly, this difference in photochemical behaviour is completely in line with the related photophysical parameters, where 2, 3, and 5/6, but not 4, show long-lived excited states at ambient temperature necessary for this type of photoreaction. Furthermore, the photochemical as well as the photophysical properties of 2-4 are also in accordance with their single crystal X-ray structures presented in this work. It seems likely that differences in "steric pressure" play a major role for these properties. The unique complexes 7-9 are also fully characterized by single-crystal X-ray structure analyses, clearly showing that the stretching vibration modes of the ligand CH(3)CN, present only in 7-9, cannot be directly influenced by "steric pressure". This has dramatic consequences for their photophysical parameters. The trans-[Ru(bpy)(CH(3)CN)(2)](2+) chromophore of 9 acts as efficient "antenna" for visible light-driven energy transfer to the Os-centred "trap" site, resulting in k(en) ≥ 2 × 10(9) s(-1) for the energy transfer. Since electron transfer is made possible by the use of this intervening energy transfer, in dyads like 2-4 highly reactive M(0) species (M = Pt, Pd, Ni) could be generated. These species are not stable in water and M(II) hydride intermediates are usually formed, further reacting with H(+) to give H(2). Thus, derivatives of 3, namely [M(bpy)(2)(dppcb)Pd(bpy)](PF(6))(4) (M = Os, Ru) dissolved in 1:1 (v/v) H(2)O-CH(3)CN produce H(2) during photolysis with visible light.
    Preview · Article · Dec 2010 · Dalton Transactions
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    ABSTRACT: The novel dimer of the composition [Pt2Cl4(μ-(κP1:κP2-o-MeO-trans-dppen))2] (1) (o-MeO-trans-dppen=1,2-(bis(o-methoxyphenyl)phosphanyl)ethylene) has been prepared and characterized by a single crystal X-ray structure analysis, NMR spectroscopy, mass spectrometry and elemental analysis. This latter compound undergoes a [2+2] photocycloaddition reaction yielding the tetraphosphane all-trans-1,2,3,4-tetrakis(di(o-methoxyphenyl)phosphanyl)cyclobutane (o-MeO-dppcb). The X-ray structure of the dimeric Ni(II) complex that contains the latter ligand, of the formula [Ni2Cl4(μ-(κP1:κP2:κP3:κP4-o-MeO-dppcb))] (2) reveals that the apical coordination sites of both square pyramidal Ni(II) coordination spheres are occupied by methoxy-oxygen atoms of the ligand. As a consequence, this dimeric Ni(II) complex 2 is prone to a thermally induced regio- and diastereoselective metal-assisted methoxy-group cleavage. The stepwise formed new mono- and bis-phenolate complexes [Ni2Cl3(μ-(κO1,κP1:κP2:κP3:κP4-o-MeO-O-dppcb))] (3) and [Ni2Cl2(μ-(κO1,κP1:κP2:κO2,κP3:κP4-o-MeO-O,O′-dppcb))] (4), respectively, contain the novel chiral tetraphosphane ligands all-trans-1,2,3-tris((di-o-methoxyphenyl)phosphano)-4-((o-methoxy-phenyl)(o-phenolate)phosphano)cyclobutane (o-MeO-O-dppcb) and all-trans-1,2-bis((di-o-methoxyphenyl)phosphano)-3,4-bis((o-methoxyphenyl)(o-phenolate)phosphano)cyclobutane (o-MeO-O,O′-dppcb). Compounds 3 and 4 have been synthesized independently and are also fully characterized by both single crystal X-ray structure analyses, NMR spectroscopy, mass spectrometry and elemental analyses. The conversion of 2 into 3 and then further into 4 has been followed by a variable-temperature 31P{1H} NMR experiment with compound 2 in DMF-d7, revealing that the cleavage of the second methoxy group is kinetically disfavoured. This is in agreement with the X-ray structure analysis of 3, indicating the lack of any methoxy-oxygen atom coordination that could easily induce a further methoxy-group cleavage. o-MeO-O-dppcb and o-MeO-O,O′-dppcb are rare P-stereogenic tetraphosphine ligands and contribute to the synthetic field of new κ3-P,P,O-coordinating phosphanylphenolate ligands that are believed to be important for the SHOP process (SHOP, Shell Higher Olefin Process).
    No preview · Article · Jun 2010 · Inorganica Chimica Acta
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    ABSTRACT: The tetraphosphane all trans tetrakis-(di(2-methoxyphenyl)phosphanyl)cyclobutane) (o-MeO-dppcb) has been employed to coordinate metal dichlorides (metal = Ni(II), Pd(II) and Pt(II)), stereoselectively yielding the dinuclear complexes [Ni(2)Cl(4)(micro-(kappaP(1):kappaP(2):kappaP(3):kappaP(4)-o-MeO-dppcb))] and [Pt(2)Cl(4)(micro-(kappaP(1),kappaP(2):kappaP(3),kappaP(4)-o-MeO-dppcb))], characterized by two six and two five-membered metallacycles, respectively. Conversely, the reaction with PdCl(2) led, under comparable synthetic conditions, to the formation of the linkage-isomeric pair [Pd(2)Cl(4)(micro-(kappaP(1),kappaP(2):kappaP(3),kappaP(4)-o-MeO-dppcb))] and [Pd(2)Cl(4)(micro-(kappaP(1):kappaP(2):kappaP(3):kappaP(4)-o-MeO-dppcb))] in a ca. 4 : 1 ratio. The compounds obtained have been characterized in solution by multinuclear NMR spectroscopy and in the solid state by CP-MAS NMR spectroscopy, XRPD and single crystal X-ray diffraction. Compounds and have been tested as catalyst precursors for the CO-ethene-propene co-and terpolymerization in water-acetic acid mixtures. Their catalytic performance has been compared to that of [PdCl(2)(o-MeO-dppe)] (o-MeO-dppe = 1,2-(bis(di(2-methoxyphenyl)phosphanyl))ethane) and of [PdCl(2)(o-MeO-dppp)] (o-MeO-dppp = 1,3-bis(di(2-methoxyphenyl)phosphanyl)propane). The most striking result that emerged from the CO-ethene copolymerization study was that was three times more productive than , outperforming, under identical catalytic conditions, even 1b and 1c, that are classified amongst the most active catalysts for the CO-ethene copolymerization reaction.
    No preview · Article · Apr 2009 · Dalton Transactions
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    ABSTRACT: The bis(bidentate) phosphine cis,trans,cis-1,2,3,4-tetrakis(diphenylphosphino)cyclobutane (dppcb) has been regioselectively oxidized leading to novel, hemilabile ligands. [Co2Cl4(dppcb)] (1a) is transformed via cobalt(II) mediated dioxygen activation into [Co2Cl4(2,3-trans-dppcbO2)] (2a) in excellent yield, where 2,3-trans-dppcbO2 is cis,trans,cis-2,3-bis(diphenylphosphinoyl)-1,4-bis(diphenylphosphino)-cyclobutane. By contrast, the in situ presence of dioxygen during the synthesis of Co2Br4(dppcb)] (1b) produces both [Co2Br4(2,3-trans-dppcbO2)] (2b) and [Co2Br4(1,3-trans-dppcbO2)] (3), where 1,3-trans-dppcbO2 is cis,trans,cis-1,3-bis(diphenylphosphinoyl)-2,4-bis(diphenylphosphino)-cyclobutane. The new compounds 2a, 2b and 3 have been obtained as pure, crystalline solids and all three X-ray structure analyses have been performed showing folded cyclobutane rings. Interestingly, the corresponding reaction using [Co2I4(dppcb)] (1c) proceeds chemoselectively. Thus, [Co2I4(dppcbO3)] (4), where dppcbO3 is cis,trans,cis-1,2,3-tris(diphenylphosphinoyl)-4-diphenylphosphinocyclobutane, is formed in excellent yield and also fully characterized by an X-ray structure analysis showing two different conformations of 4. However, [Co2(NO3)4(dppcb)] (1d) shows no dioxygen activation at all. Therefore, in order to reveal the mechanism of this oxidation [Co2I4(DMF)2(dppcb)] (5) has been prepared and its X-ray structure is presented. The synthesis of [Co2I4(PMe2Ph)2(dppcb)] (6) proves that this is a common reaction pathway. Furthermore, because the product distribution of the oxidation strongly depends on the kind of halides present, the whole series Co2X4(dppcbO4)] (X = Cl, 7a; Br, 7b; I, 7c) has been prepared, where dppcbO4 is cis,trans,cis-1,2,3,4-tetrakis(diphenylphosphinoyl)-cyclobutane, and all three X-ray structures are given, also showing folded cyclobutane rings. It seems likely that coordination of dppcb to cobalt(II) is essential to form the regio- and chemoselectively oxygenated molecules.
    No preview · Article · Mar 2009 · Dalton Transactions
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    ABSTRACT: For the first time the excited states of the RuP2N4 moiety belonging to a new heterodimetallic OsII–RuII bipyridyl complex are successfully designed in order to introduce photochemical reactivity. This dramatic effect is achieved via the use of the sterically demanding bis(bidentate) phosphine cis, trans, cis-1,2,3,4-tetrakis(diphenylphosphino)cyclobutane (dppcb). Thus, the temperature dependence of the luminescence lifetimes ranging from 77 to 298K for the novel homodimetallic species meso-(ΔΛ/ΛΔ)-[Os2(dppcb)(bpy)4](PF6)4 (1) and rac-(ΔΔ/ΛΛ)-[Os2(dppcb)(bpy)4](PF6)4 (2) clearly indicates that the d–d state responsible for photochemistry is not populated. By contrast, the analogous temperature dependence for the new heterodimetallic species ΔΛ/ΛΔ-[Os(bpy)2(dppcb)Ru(bpy)2](PF6)4 (3) and ΔΔ/ΛΛ-[Os(bpy)2(dppcb)Ru(bpy)2](PF6)4 (4) unequivocally shows that as a consequence of the population of the d–d state the photochemical reactivity is switched on. Since single crystal X-ray structure analyses are a major clue to the understanding of photophysical and photochemical properties, also the X-ray structures of 1–3 are given.
    No preview · Article · Dec 2007 · Inorganic Chemistry Communications
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    ABSTRACT: Fifteen novel homodimetallic RhI and IrI complexes containing the bis(bidentate) phosphane ligand cis,trans,cis-1,2,3,4-tetrakis(diphenylphosphanyl)cyclobutane (dppcb) were prepared and characterized by NMR spectroscopy (1H, 13C{1H}, 31P{1H}), mass spectrometry, IR spectroscopy, elemental analyses and melting points. Furthermore, the solid-state structures of seven of these new compounds were fully determined by single-crystal X-ray diffraction analyses to study the influence of steric pressure. The precursor complex [Rh2(η4-cod)2(dppcb)]X2 (1), X– = BF4–, PF6–, SbF6–, completely characterized by its X-ray structure, smoothly reacts with mono- or bidentate ligands containing phosphorus or nitrogen donor atoms. Thus, monophosphanes and monophosphites produce compounds of the structure type [Rh2L4(dppcb)](SbF6)2 [L = PMe2Ph, 2; PMePh2, 3; P(OMe)3, 5; P(OPh)3, 6]. The X-ray structures of 3 and 6 show that PMePh2 and P(OPh)3 are capable of compensating steric interactions. The treatment of 1 with diphosphanes leads to the structure type [Rh2L2(dppcb)](SbF6)2 [L = bis(diphosphanyl)methane, dppm, 7; bis(diphenylphosphanyl)amine, dppam, 8; 1,2-bis(diphenylphosphanyl)ethane, dppe, 9; cis-1,2-bis(diphenylphosphanyl)ethene, cis-dppen, 10]. The X-ray structures of 8, 9 and 10 clearly indicate the onset of steric pressure as a consequence of mechanical coupling, which results in two different coordination moieties for homodimetallic species 9 and 10. Under steric pressure, the quadrant effects of dppcb and dppe become comparable to RhI complexes. The use of mono- or bidentate ligands containing nitrogen donor atoms leads to the compounds [Rh2(pyridine)4(dppcb)](SbF6)2 (11), [Rh2(2,2′-bipyridine)2(dppcb)](SbF6)2 (12) and [Rh2(1,10-phenanthroline)2(dppcb)](SbF6)2 (13). The crystal structures of 1 and the novel complex [Ir2(η4-cod)2(dppcb)]X2 (14), X– = BF4–, SbF6–, are isomorphous. However, it was only possible to produce restricted examples of derivatives of 14 owing to the reluctance of 14 to release cod. Thus, monophosphanes lead to the five-coordinate species [Ir2(η4-cod)2(PMe2Ph)2(dppcb)](BF4)2 (15), whereas the four-coordinate compound [Ir2(PMePh2)4(dppcb)](BF4)2 (16) is formed by using the sterically more demanding ligand PMePh2 instead of PMe2Ph. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
    No preview · Article · Jul 2007 · Berichte der deutschen chemischen Gesellschaft
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    ABSTRACT: The bis-cationic diphosphonium-diphosphine 6,7-di(di-2-methoxyphenyl)phosphinyl-2,2,4,4-tetra(di-2-methoxyphenyl)-2 lambda 4,4 lambda 4-diphosphoniumbicyclo[3.1.1]heptane-bis(PF6) ((o-MeO-PCP)(PF6)2) and the diphosphine rac-2,4-bis((di-2-methoxyphenyl)phosphino)pentane (rac-o-MeO-bdpp) have been synthesized. Both ligands have been employed to coordinate PdCl2 and Pd(OAc)2 to give [PdCl2(o-MeO-PCP)](PF6)2 (1a), PdCl2(rac-o-MeO-bdpp) (1b), [Pd(OAc)2(o-MeO-PCP)](PF6)2 (2a) and Pd(OAc)2(rac-o-MeO-bdpp) (2b). The ligands and complexes have been fully characterized in solution by multinuclear NMR spectroscopy. In addition, 1a and 1b have been authenticated by single crystal X-ray structure analyses. The Pd(II) complexes 1a and 1b have been employed as catalyst precursors for the CO/ethene copolymerisation in water-acetic acid mixtures, while 2a and 2b have been tested in methanol in the presence of p-toluenesulfonic acid. Irrespective of the reaction media, perfectly alternating polyketones were obtained in excellent yields and with number-average molecular weights ranging from 7.1-13.9 kg mol(-1) with the diphosphonium-diphosphine catalysts and from 37.2-48.2 kg mol(-1) with the diphosphine catalysts.
    Full-text · Article · Jul 2006 · Dalton Transactions
  • W. Oberhauser · A. Dumfort · P. Brueggeller

    No preview · Article · Aug 2005 · Acta Crystallographica Section A Foundations of Crystallography
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    ABSTRACT: A new azamacrocycle phosphonate in its hydrocloride form (1) has been synthesized and characterised by multinuclear NMR spectroscopy and by a single X-ray analysis. The reaction of 1 with CuII ions gives a polymeric compound (2), which exhibits an unprecedented three-dimensional network containing two-dimensional channels filled with guest molecules. The solid-state structure of 2 and its properties have been characterised by means of various analytical methods which include single-crystal X-ray structure analysis, X-ray powder diffraction, thermogravimetric studies as well as magnetic susceptibility and EPR measurements. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
    No preview · Article · Jun 2005 · Berichte der deutschen chemischen Gesellschaft
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    ABSTRACT: We report the first observation of conformational modulation of the efficiency of luminescence of a chelating phosphine containing a saturated backbone and combined with [Ru(bpy)2]2+. The observed luminescent lifetimes are very long: 910(20) ns in CD3CN and 794(20) ns in CH3CN at 298 K. The bimetallic structure of rac-(ΔΔ/ΛΛ)-[Ru2(dppcb)(bpy)4](PF6)4 (1) and meso-(ΔΛ/ΛΔ)-[Ru2(dppcb)(bpy)4](PF6)4 (2), where dppcb is cis, trans, cis-1,2,3,4-tetrakis(diphenylphosphino)cyclobutane, is responsible for this dramatic effect. An enhanced folding of the cyclobutane rings drastically reduces the efficiency of luminescence as observed in the new monometallic complexes [Ru(dppcb)(bpy)2](PF6)2 (3) and [Ru(dppcbO2)(bpy)2](PF6)2 (4), where dppcbO2 is cis, trans, cis-1,2-bis(diphenylphosphinoyl)-3,4-bis(diphenylphosphino)cyclobutane.
    No preview · Article · Mar 2005 · Inorganic Chemistry Communications
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    ABSTRACT: The structure of the title compound, C23H32O4, an arylalkanone isolated from the petroleum ether fraction of the ethanol extract of the bark of Virola venosa, has been established by NMR spectroscopy and, for the first time, by X-ray structure analysis. Two independent molecules of the same enantiomer are present in the unit cell. Both molecules exhibit an intramolecular hydrogen bond, which can be correlated with a rare signal observed at 18.28 p.p.m. in the 1H NMR spectrum. The packing, in space group P1, is determined by a pseudo-center of symmetry leading to a short intermolecular contact, which is present in one molecule but does not occur in the other. As a consequence, the O-C-C-O torsion angles [-16.9 (3) and -12.7 (3) degrees ] through the ketone and its adjacent hydroxy group are significantly different in the two molecules.
    No preview · Article · Aug 2004 · Acta Crystallographica Section C Crystal Structure Communications
  • Luis E. Cuca Suarez · Rene Gutmann · Georg Czermak · Peter Brueggeller
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    ABSTRACT: this paper are available from the IUCr electronic archives (Reference: SX1132). Services for accessing these data are described at the back of the journal
    No preview · Article · Jul 2004