bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nitric Oxide Reduction by Heme‐Thiolate Enzymes (P450nor): A Reevaluation of the Mechanism
Authors: Silaghi‐Dumitrescu Radu 
Published: March 2003

AbstractThe details of the heme‐thiolate nitric oxide reductase (P450nor) catalytic mechanism are still controversial. One theory, supported by computational results [D. L. Harris, Int. J. Quantum Chem. 2002, 88, 183−200], assumes two sequential one‐electron transfers from NAD(P)H to an initial [FeNO]6 complex. The [FeNO]8 species thus formed would react with NO, eventually liberating the unstable ONNO2− anion (most probably in its protonated form), which decomposes to N2O and water. However, more recent experimental results [A. Daiber et al., J. Inorg. Biochem. 2002, 88, 343−352] suggest the first committed step of the mechanism to be direct hydride transfer from NAD(P)H to [FeNO]6, presumably resulting in an iron‐bound HNO unit, [Fe‐(H)NO]8, that would be readily protonated to [Fe‐(H)NOH]8. Subsequent NO addition would yield the unstable HO‐N(H)‐N=O, which would dissociate from the heme and decompose to H2O and N2O. Here, the DFT geometry optimization of all previously proposed reaction intermediates is reported. The first step of the mechanism is predicted to be hydride transfer to [FeNO]6, to produce [FeNOH]8 or [Fe‐N(H)O]8. Subsequent addition of NO to [Fe‐NOH]8 (but not to [Fe‐N(H)O]8 or [Fe‐N(H)OH]8) is predicted to lead to immediate liberation of HN2O2−, without any stable intermediates. Contrary to what would be predicted according to the “thiolate push effect” dogma, the thiolate ligand at the heme active site is shown to obstruct NO reduction, rather than facilitate it. It is in fact shown that replacement of the thiolate by a neutral nitrogen ligand (i.e., lysine, as found in the active site of cytochrome c nitrite reductase, an enzyme that can reduce NO) clearly favors, from a thermodynamic point of view, NO reduction at the heme site. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Synthesis, Crystal and Electronic Structure of [Hg7As4](AgI3)2, a Novel Supramolecular Complex with the Off‐Plane AgI32− Guest Anion
Authors: Olenev Andrei V. , Baranov Alexei I. , Oleneva Olga S. , Vorontsov Ivan I. , Antipin Mikhail Yu. , Shevelkov Andrei V. 
Published: March 2003

AbstractA novel supramolecular inorganic complex [Hg7As4](AgI3)2 has been prepared and its crystal structure determined. It crystallizes in the cubic system (space group Pa$\bar 3$
) with the unit cell parameter a = 13.138(1) Å and Z = 4. The crystal structure comprises a three‐dimensional positively charged host framework [Hg7As4]4+ with AgI32− guest anions trapped in each cavity of the framework. The guest anion shows an unusual off‐plane geometry (C3v symmetry), with a large, anisotropic thermal displacement parameter for the silver atom, which lowers significantly upon cooling from 293 down to 120 K. A study of the electronic structure shows that, although the host‐guest interaction is weak and diffuse, it governs both the geometry of the guest anion and its positioning within the framework cavities. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Structural Investigation of the Thermal Decomposition of Ammonium Heptamolybdate by in situ XAFS and XRD
Authors: Wienold Julia , Jentoft Rolf E. , Ressler Thorsten 
Published: March 2003

AbstractThe decomposition of ammonium heptamolybdate (AHM, (NH4)6Mo7O24×4H2O) was studied in situ by X‐ray diffraction and X‐ray absorption spectroscopy, as well as by thermal analysis (TG/DTA). Decomposition conditions such as reactant atmospheres, (20% oxygen, 5% propene, 5% hydrogen, pure helium, and static air), heating rates, and gas flow rates were varied to investigate their influence on the decomposition process. The results obtained show that the reaction pathway is affected by the partial pressures of the gas‐phase decomposition products. The partial pressures of the decomposition products, water and ammonia, at a given temperature, is influenced mainly by the reactant gas flow rate and the heating rate. Lowering the partial pressures of ammonia and water inhibits the crystallization of the intermediate ammonium tetramolybdate (ATM), and promotes the formation of the intermediate hexagonal MoO3. The decomposition pathway under low gas phase product partial pressure is: (i) AHM; (ii) (ca. 335 K) X‐ray amorphous phase; (iii) (ca. 520 K) hexagonal MoO3; (iv) (ca. 650 K) the products, which depend on the reactant atmosphere, are mixtures of highly disordered Mo4O11, and/or α‐MoO3. Under different conditions the decomposition pathway is: (i) AHM; (ii) (ca. 350 K) X‐ray amorphous phase; (iii) (ca. 470 K) ATM; (iv) (ca. 570 K) hexagonal MoO3 + α‐MoO3; (ca. 650 K) α‐MoO3. Under a hydrogen containing atmosphere, a peculiar decomposition pathway is observed: an intermediate MoO3 with an unusual texture is formed prior to the reduction to MoO2 and the consecutive formation of orthorhombic Mo4O11. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
3‐Metalla‐1,2‐dioxolanes and Their Reactivity
Authors: Krom Monique , Peters Theo P. J. , Coumans Ruud G. E. , Sciarone Timo J. J. , Hoogboom Johan , ter Beek Sandra I. , Schlebos Paul P. J. , Smits Jan M. M. , de Gelder René , Gal Anton W. 
Published: March 2003

AbstractThe ethene complexes [MI(CH2CH2)]+ (M = Ir, Rh) can be oxygenated by molecular oxygen or air in the solid state, to form isolable unsubstituted 3‐metalla‐1,2‐dioxolanes [MIII(CH2CH2OO‐κ2C1,O2)]+. Such selectivity could not be achieved in solution. The stereoselectivity of the oxygenation process is highly dependent on the ligand, the metal and the counterion used. Oxygenation of [(tpa)M(CH2CH2)]PF6 {tpa = tri(2‐pyridylmethyl)amine; 4PF6, 7PF6} results in the formation of two isomeric 3‐metalladioxolanes, whereas oxygenation of [(tpa)M(CH2CH2)]BPh4 (4BPh4, 7BPh4) only yields one isomer. Furthermore, oxygenation of [(Metpa)Rh(CH2CH2)]PF6 {14PF6, Metpa = [(6‐methyl‐2‐pyridyl)methyl]bis(2‐pyridylmethyl)amine} proved to be much slower than that of [(tpa)Rh(CH2CH2)]PF6 (7PF6). The solid propene complex [(tpa)Rh(CH2CHCH3)]BPh4 (23BPh4) loses propene on reaction with molecular oxygen, and selectively forms the peroxo complex [(tpa)Rh(η2‐O2)]BPh4 (24BPh4). The obtained 3‐metalla‐1,2‐dioxolanes rearrange, both in the solid state and in solution, to formylmethyl hydroxy complexes on exposure to photons or protons. The isomeric 3‐rhoda‐1,2‐dioxolanes [(tpa)Rh(CH2CH2OO‐κ2C1,O2)]+ 8a+ and 8b+ differ in reactivity. On exposure of a solution of 8aPF6/8bPF6 to glass‐filtered daylight, isomer 8b+ rearranges to form the formylmethyl hydroxy complex 9b+. This rearrangement is three times faster than the rearrangement of 8a+ to 9a+. The iridadioxolanes are much more reactive than the corresponding rhodadioxolanes, whereas the iridium formylmethyl hydroxy complexes are less reactive than the corresponding rhodium formylmethyl hydroxy complexes. The tpa formylmethyl hydroxy complexes react reversibly with carbon dioxide to form formylmethyl hydrogen carbonate complexes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Chelate Complexes of Functionalized Cycloheptatrienyl Ligands: Molybdenum Complexes with Linked Cycloheptatrienyl‐Phosphane Ligands and Their Use in Catalytic Carbon−Carbon Bond Formation
Authors: Tamm Matthias , Dreßel Bernd , Lügger Thomas , Fröhlich Roland , Grimme Stefan 
Published: March 2003

AbstractThe synthesis of P‐functionalized molybdenum chelate complexes incorporating the linked cycloheptatrienyl‐phosphane ligand [2‐(diisopropylphosphanyl)phenyl]cycloheptatrienyl (o‐iPr2P−C6H4−C7H6) is described. From the ligand precursor [2‐(cyclohepta‐2,4,6‐trienyl)phenyl]diisopropylphosphane (1) the paramagnetic 17‐electron dibromide [(o‐iPr2PC6H4‐η7‐C7H6)MoBr2(P−Mo)] (2) can readily be obtained. This is a versatile starting material for the preparation of cycloheptatrienyl molybdenum hydrides [(o‐iPr2PC6H4‐η7‐C7H6)Mo(η2‐BH4)(P−Mo)] (3) and [(o‐iPr2PC6H4‐η7‐C7H6)Mo(PPh3)H(P−Mo)] (4). Treatment of 3 with dimethylanilinium tetraphenylborate ([PhNMe2H][BPh4]) allows the production of the cationic 14‐electron complex fragment [(o‐iPr2PC6H4‐η7‐C7H6)Mo(P−Mo)]+ (13), which can be stabilized in the presence of suitable ligands L. The complexes [(o‐iPr2PC6H4‐η7‐C7H6)MoL2(P−Mo)]BPh4 [L = dimethylphenyl isocyanide, (5)BPh4; L2 = η4‐2,5‐norbornadiene, (6)BPh4; L2 = η2‐phenylacetylene, (7)BPh4; L2 = η2‐tert‐butylacetylene, (8)BPh4] can thus be isolated in good yields. The alkyne complex (7)BPh4 can be used as a single‐source catalyst for the oligomerization of phenylacetylene, affording a mixture of triphenylbenzenes and linear oligomers. Quantum chemical calculations reveal an intimate relationship between the catalytically active 14‐electron complex fragment [(o‐iPr2PC6H4‐η7‐C7H6)Mo(P−Mo)]+ (13) and hypothetical isoelectronic and isolobal complexes of the type [(o‐iPr2PC6H4‐η5‐C5H4)M(P−M)]+ (M = Ru, 14; M = Os, 15), indicating that cycloheptatrienyl molybdenum systems might in general be a suitable replacement for cyclopentadienyl ruthenium and osmium catalysts. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Modes of Reactivity of Cyclic Diynes: Probing the syn/anti Selectivity of Tetrathiacycloalkadiynes and Mono(alkyne)cobalt Complexes
Authors: Benisch Christoph , Werz Daniel B. , Gleiter Rolf , Rominger Frank , Oeser Thomas 
Published: March 2003

AbstractCyclic tetrathiaalkadiynes in which two 1,4‐dithiaalkyne units are connected with alkane bridges of length n and m [A(m.n)] were treated with [η2‐bis(tert‐butylsulfonyl)acetylene]carbonyl(η5‐cyclopentadienyl)cobalt(I) (8a) and several substituted analogues (8b−8e) in order to probe the reactivity of electron‐rich cyclic diynes. Both mono‐ [B(m.n)] and bis(cyclobutadiene) [C(m.n)] complexes were isolated as products of these reactions and the anti/syn ratio of C(m.n) was determined. For m, n < 4 the syn isomers dominate and this is attributed to the configuration of the intermediate metallacycle which is correlated with the conformations of the rings in the mono(cyclobutadiene) products B(m.n). This analysis was corroborated by X‐ray structural investigations of the products. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Mono‐ and Dimetallic Cyano Complexes with {Mo(η3‐allyl)(CO)2(N−N)} Fragments
Authors: Pérez Julio , Hevia Eva , Riera Lucía , Riera Víctor , García‐Granda Santiago , García‐Rodríguez Esther , Miguel Daniel 
Published: March 2003

AbstractTreatment of [MoCl(η3‐allyl)(CO)2(phen)] with NaCN in CH2Cl2/MeOH afforded [Mo(CN)(η3‐allyl)(CO)2(phen)] [allyl = C3H5 (1a); 2‐MeC3H4 (1b)] as the sole products (no products of cyanide attack on the allyl group were detected). Treatment of 1a,b with [Mo(OTf)(η3‐C3H5)(CO)2(phen)] and NaBAr′4 in CH2Cl2 yielded the compounds [{Mo(η3allyl)(CO)2(phen)}(μ‐CN){Mo(η3‐C3H5)(CO)2(phen)}]BAr′4 (2a,b). Analogous treatment of 1a with fac‐[M(OTf)(CO)3(bipy)] (M = Mn, Re) and NaBAr′4 resulted in the synthesis of [{Mo(η3‐C3H5)(CO)2(phen)}(μ‐CN){M(CO)3(bipy)}]BAr′4 (3, 4), in which the C and N atoms of the cyano bridge are bonded to Mo and M (M = Mn, Re), respectively. The linkage isomer of 4 (C and N atoms of the cyano group bonded to Re and Mo, respectively) (6) was prepared by treatment of [Re(CN)(CO)3(bipy)] (5) with [Mo(OTf)(η3‐C3H5)(CO)2(phen)] and NaBAr′4. Compounds 1a, 2b, 3, and 6 were characterized by X‐ray diffraction. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Charge‐Transfer Mechanisms between Gold Clusters
Authors: Torma Viktoria , Vidoni Olivia , Simon Ulrich , Schmid Günter 
Published: March 2003

AbstractElectron‐transfer processes in complex chemistry are usually described by Taube’s “outer sphere” and “inner sphere” mechanisms. A behaviour related to these electron‐transfer mechanisms in complex chemistry can be observed for charge‐transfer transport between ligand protected Au55 nanoclusters. A linear dependence between cluster‐cluster distance and activation energy for electron transfer is observed if a noncovalent linkage exists; this interaction is independent of the distance in covalently linked clusters. Instead, the activation energy depends on the electronic nature of the linking molecules. The dithiols 1,5‐dithionaphthaline (1), 4,4′‐thiobis(benzenethiol) (2), and 2,8‐dithio‐6‐hydroxypurine (3) have been used as bifunctional covalent linkers either in their monomeric form (2) or, in the presence of air, dimerized via S−S bonds (1, 2, 3), causing an increase in the distance between the clusters and leading to the cluster networks 4−7. Noncovalent cluster networks are formed either by pellets of clusters with monodentate ligands in 8 and 11, linked only by van der Waals forces, or by using bifunctional spacers that interact with the clusters by ion attractions (9, 10). A study of the activation energies clearly indicates that in the case of noncovalently organized nanoparticles only the cluster spacing is of relevance, even if conjugated π‐systems like in 10 are used. This behaviour corresponds to an outer‐sphere mechanism. On the contrary, for covalently linked clusters the distances between them does not play a visible role. The activation energies all lie below those of the noncovalent examples, and a relation between cluster‐cluster distance and activation energy is not obvious. In those cases the relationship suggests an inner‐sphere mechanism where the transport properties of the spacer play a decisive role. These findings possibly help to explain contradictory reports on the conductivity behaviour of organic molecules. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Monohelical Complexes of a Novel Asymmetric N4 Schiff Base: Unfamiliar Tetrahedral Environments of Manganese(II) and Iron(II) Helicates
Authors: Vázquez Miguel , Bermejo Manuel R. , Fondo Matilde , García‐Deibe Ana M. , Sanmartín Jesús , Pedrido Rosa , Sorace Lorenzo , Gatteschi Dante 
Published: March 2003

AbstractThe electrochemical reaction of the bis‐bidentate H2ABATs Schiff base [H2ABATs = N,N′‐bis(2‐tosylaminobenzylidene)‐2‐aminobenzylamine] with manganese, iron, cobalt, nickel, copper, zinc and cadmium was investigated. The reaction cell yields products of empirical formula M(ABATs). X‐ray diffraction studies show that [Mn(ABATs)]·0.75H2O (1), [Fe(ABATs)]·0.75H2O (2), [Ni(ABATs)]·0.75H2O (3), [Cu(ABATs)]·0.5H2O (4) and [Zn(ABATs)]·0.75H2O (5) are mononuclear distorted tetrahedral helical complexes in the solid state. Complexes 1 and 2 confirm the ability of this type of ligand to dictate the geometry around the metal centre, as is shown by the unfamiliar tetrahedral environments of manganese(II) and iron(II) ions in complexation with the Schiff bases. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Mono‐ and Bis‐Guanosine Adducts of Platinum Complexes with Carrier Ligands Having In‐Plane Steric Bulk: The Case of 1,10‐Phenanthroline and 2,9‐Dimethyl‐1,10‐phenanthroline
Authors: Margiotta Nicola , Papadia Paride , Fanizzi Francesco P. , Natile Giovanni 
Published: March 2003

AbstractThe steric hindrance generated by carrier ligands, in particular incis‐PtA2G2adducts (A2= diamine,G= guanine derivative), has often been used to slow down rotation about the platinum‐guanine bonds, thus allowing the characterisation of different conformers and the analysis of the interactions that are involved in the stabilisation of cisplatin adducts with DNA. In a previous study concerning 1,10‐phenanthroline and 2,9‐dimethyl‐1,10‐phenanthroline (phen and Me2phen, respectively), the Me2phen ligand was reported to form an unusual bis‐guanosine derivative with atransdisposition of the nucleobases and monodentate Me2phen. The present investigation has demonstrated that phen and Me2phen, like other bidentate ligands, allow formation of both mono‐ and bis‐guanosine derivatives, the latter having the usualcisconfiguration. In both the phen and Me2phen carrier ligands the rigidity of the phenanthroline skeleton is able to hinder rotation of the guanosine base(s) about the Pt−N(7) bond(s) and render the interconversion between rotamers slow on the NMR timescale even at 350 K (the highest temperature explored). However there are noticeable differences between the two ligands. As a consequence of the increased in‐plane steric bulk of Me2phen: (i) the H(8) chemical shifts within theHH(Head‐to‐Head) conformer and between theHT(Head‐to‐Tail) conformers become closer, (ii) the average H(8) chemical shift of theHTconformers is at higher field and that of theHHform at lower field, and (iii) theHTrotamers become even more favoured than theHHrotamer. Observation (ii) is in agreement with theHTrotamers preferring the “6‐in” conformation, which brings the six‐membered rings of the guanines closer to one another and is also in agreement with the phen ligand allowing a greater canting of the guanine bases than Me2phen. Moreover, free chloride ion readily displaces the coordinated guanosines, particularly in solvents of lower dielectric constants than water. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Structural Variations and Formation Constants of First‐Row Transition Metal Complexes of Biologically Active Aroylhydrazones
Authors: Armstrong Claire M. , Bernhardt Paul V. , Chin Piao , Richardson Des R. 
Published: March 2003

AbstractIron chelators of the 2‐pyridinecarbaldehyde isonicotinoylhydrazone (HPCIH) class show high potential for the treatment of iron overload diseases. In the present study, selected first‐row transition metal (from Mn to Zn) complexes with HPCIH and 2‐pyridinecarbaldehyde (4′‐aminobenzoyl)hydrazone (HPCAH) were synthesised and characterised. Crystallography reveals that HPCAH exclusively forms bis complexes with divalent transition metals, with each ligand coordinating meridionally through its pyridine‐N, imine‐N and carbonyl‐O atoms, forming distorted octahedral cis‐MN4O2 complexes. Complexes of HPCIH were more varied and unpredictable, with metal/ligand ratios of 1:1, 1:2, 2:2 and 3:2 obtained with different metal ions. The isonicotinoyl ring N‐atom in HPCIH was found to be an effective ligand, and this resulted in the varied metal/ligand ratios observed. The formation constants of divalent metal complexes with HPCIH were determined by potentiometric titrations and the values obtained were consistent with similar tridentate ligands and with the Irving−Williams order. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
New Rhenium(I) and Rhenium(II) Species Assembled by Stereospecific Azopyridine Chelation
Authors: Sengupta Suman , Chakraborty Indranil , Chakravorty Animesh 
Published: March 2003

AbstractThe spontaneous reaction of [ReO(OEt)I2(PPh3)2] with 2,2′‐azobipyridine (L) in acetonitrile, and of [ReOCl3(PPh3)2] with L in toluene, proceeds stereospecifically furnishing the green tris‐chelate [ReIL3]I (1) and the red bis‐chelate [ReIICl2L2] (2), respectively. A structure determination reveals that the coordination geometry of 1 is facial and that of 2 is cis(Cl,Cl)‐trans(Np,Np)‐cis(Na,Na) (Np is a pyridine nitrogen and Na is an azo nitrogen). The isomer preference is exclusive in both cases and no other isomer has been observed. The average N−N distance in both compounds is about 1.35 Å, signifying the presence of strong d(Re)‐π*(azo) back‐bonding which plays a crucial role in controlling isomer specificity. The bis‐chelate 2 is a one‐electron paramagnet and displays a six‐line EPR spectrum in fluid solution with g = 2.080 and A = 320 G. The 1H NMR spectrum of diamagnetic 1 is consistent with the facial geometry. In acetonitrile solution 1 displays an ReII/ReI couple and 2 an ReIII/ReII couple, the reduction potentials being 0.60 and 0.50V vs. SCE respectively. The violet‐coloured imide complex [ReVCl3(NC6H4Cl‐p)L] (3) is also reported; it displays an ReVI/ReV redox wave at 1.33 V vs. SCE. The stabilization of the lower rhenium oxidation states in 1 and 2 is consistent with the decrease of metal reduction potential with progressive L chelation. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
[Bis(oxazolinyl)pyrrole]palladium Complexes as Catalysts in Heck‐ and Suzuki‐Type C−C Coupling Reactions
Authors: Mazet Clément , Gade Lutz H. 
Published: March 2003

AbstractThe two bis(oxazoline)pyrrole ligand precursors 2,5‐bis(4,4′‐dimethyl‐4,5‐dihydrooxazol‐2‐yl)pyrrole (“dmoxpH”, 2) and 2,5‐bis(4,4′‐dimethyl‐4,5‐dihydrooxazol‐2‐yl)‐3,4‐diethylpyrrole (“Et2dmoxpH”, 5) have been synthesised and metallated by treatment with n‐butyllithium at −78 °C in diethyl ether. Treatment of the lithium pyrrolide with 1.1 mol‐equiv. of [PdCl2(COD)] gave the corresponding helical dinuclear palladium complexes [Pd2Cl2(dmoxp)2] (6) and [Pd2Cl2(Et2dmoxp)2] (7). In both complexes the tridentate bis(oxazolinyl)pyrrolide ligands bridge the two metal centres, with one of the oxazoline rings and the charged pyrrolide being coordinated to the one Pd centre while the second oxazoline ring is twisted relative to the pyrrolide unit and coordinates to the second palladium atom. Complexes 6 and 7 were found to be precursors for active catalysts for Heck coupling reactions of styrene and ethyl acrylate, with turnover numbers of over 9000 for the former, as well as for disubstituted alkenes such as methyl crotonate and methyl cinnamate. Complex 6 was found to be a very active catalyst for Suzuki coupling reactions of activated and deactivated bromoarenes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Cover Picture
Authors: Olenev Andrei V. , Baranov Alexei I. , Oleneva Olga S. , Vorontsov Ivan I. , Antipin Mikhail Yu. , Shevelkov Andrei V. 
Published: March 2003

AbstractThe cover picture shows the arrangement of the 3‐D [Hg7As4]4+ host framework and the AgI32− guest anions in a novel supramolecular architecture [Hg7As4](AgI3)2, self‐assembled from a heterogeneous system at high temperature. Although the host−guest interaction is weak, it governs both the geometry of the host framework (mercury atoms, blue; arsenic atoms, pink) and guest anions (silver atoms, red; iodine atoms, violet) and the positioning of the guest in the framework cavities. A mutual adjustment of the host and guests results is the unusual off‐plane geometry of the AgI32− anion. Details are discussed in the article of A. V. Shevelkov et al. on p. 1053 ff.
The Synthesis and Structure of P−C−P Bridged Ferrocene
Authors: Shevchenko Igor , Shakhnin Dmitrii , Zhang Hongming , Lattman Michael , Röschenthaler Gerd‐Volker 
Published: March 2003

AbstractThe reaction of dilithioferrocene 12 with methylene‐bis(dialkylaminochlorophosphanes) 13a,b (a = CH3, b = C2H5) leads to the formation of compounds 14a,b in which the two cyclopentadiene rings are bridged by a P−C−P chain. Because of the cyclic structure, cis‐ and trans‐isomerism is expected. The cis‐ and trans‐isomers of the sulfur derivative 16b have been separated by column chromatography. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Hydrothermal Synthesis and Characterisation of Two Novel Large‐Pore Framework Vanadium Silicates
Authors: Brandão Paula , Valente Anabela , Philippou Andreas , Ferreira Artur , Anderson Michael W. , Rocha João 
Published: March 2003

AbstractTwo new large‐pore sodium vanadium silicates, denoted AM‐15 and AM‐17 (Aveiro‐Manchester, structures number 15 and 17) with framework composition Na6Si14V4O39 and Na4CaSi10V2O27, respectively, are reported. Electron paramagnetic resonance (EPR), Fourier transform infrared (FTIR) and diffuse reflectance ultraviolet‐visible (DR UV/Vis) spectroscopy reveal that as‐prepared AM‐15 contains both VIV and VV in a square pyramidal and tetrahedral coordination, respectively, while AM‐17 contains predominantly octahedral VIV. The thermal stability of AM‐15 in air is modest (ca. 380 °C), while AM‐17 is stable up to 450 °C. The acid‐base and redox properties of AM‐17 have been assessed by the conversion of isopropanol and ethanol oxidation, respectively. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)