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The reaction of FcC≡C–C≡CFc [Fc = Fe(η5-C5H4)(η5-C5H5)] (1) with Co(η5-C5H5)(CO)2 (2) afforded ferrocenyl-functionalized cyclobutadiene and cyclopentadienone cobalt(I) compounds as well as multiferrocenyl benzene derivatives. The synthesis procedures are described. Eleven products could be separated by column chromatography and were characterized by NMR, UV/Vis, and IR spectroscopy, high-resolution ESI-TOF mass spectrometry and elemental analysis. For five representatives, the structure in the solid state was determined by single X-ray structure analysis. The electronic properties of the appropriate compounds were studied by using cyclic and square-wave voltammetry. Further investigation of the interaction between FeII/FeIII centers in the mixed-valent species was achieved by in situ UV/Vis/NIR spectroelectrochemistry. These measurements demonstrated that weak electronic metal–metal interactions through the cobalt-coordinated cyclobutadiene building block occur (weakly coupled class II systems according to the classification of Robin and Day), whereas the cyclopentadienone core acts as an insulator (class I), and hence only electrostatic interactions are characteristic.

The synthesis of germanium(II) 2-tert-butyl-4-methyl-6-(oxidomethyl)phenolate (1) starting from Ge[N(SiMe3)2]2 and the corresponding salicyl alcohol is reported. Compound 1 undergoes an intramolecular oxidative insertion reaction of germanium into a C–O bond to result in a cyclic germanium(IV) tetraoxidogermocane (2). Addition of 3-tert-butyl-2-hydroxy-5-methylbenzyl alcohol to either compound 1 or 2 gave a spirocyclic monoorgano dioxagermine (3). The results of 1H NMR spectroscopic studies and DFT-D calculations are in agreement with the proposed reaction cascade in which the novel germylene 1 is first converted into the germocane 2 followed by reaction with 3-tert-butyl-2-hydroxy-5-methylbenzyl alcohol to finally provide compound 3. Addition of 4-(dimethylamino)pyridine to a solution of germylene 1 resulted in the formation of an air-stable monomeric 1:1 complex (4). The characterization of compounds 1–4 by single-crystal X-ray diffraction analysis, thermal analysis, and 1H NMR, 13C{1H} NMR, and ATR-FTIR spectroscopy is presented.

Germanium(II) (2-methoxyphenyl)methoxide (1) and [W(CO)5(thf)] gave rise reproducibly (79 % yield) to a new, uncharged transition-metal complex of a germanium(II) hydroxido oxido cluster – [{Ge4(μ-O)2(μ-OH)4}{W(CO)5}4]·4THF (2·4THF) – as a product of hydrolysis. The germylene 1 is monomeric in solution at ambient temperature but forms dimers in solution at low temperatures and in the solid state. Dimerization of compound 1 was studied by 1H NMR spectroscopy and with the aid of DFT-D calculations. The tetranuclear cluster 2 shows an adamantane-like core structure with coordination of tungsten pentacarbonyl to germanium(II) in the solid state as well as in solution. Characterization of both compounds, including by single-crystal X-ray diffraction analysis, by 1H NMR, 13C{1H} NMR, FTIR spectroscopy, and through thermal analyses, is presented.

Invited for the cover of this issue is the group of Heinrich Lang at the Technische Universitat Chemnitz, Germany. The cover image shows the atom-economical and highly selective addition of carboxylic acids to propargylic alcohols to give β-oxopropyl esters. This conversion is catalyzed by ruthenium complexes, represented by the skater in our picture.

Multiferrocenyl-substituted benzenes could be obtained in a “one-pot” reaction of 1,4-diferrocenylbutadiyne with substoichiometric amounts of [CoCp(CO)2] (Cp = cyclopentadienyl) by combining cobalt-assisted formal [2+2+2] cycloaddition with C–H bond activation at a single catalyst. A mechanism for the reaction is discussed. The newly synthesized hexaferrocenyl species belongs to the rather scarcely examined family of multimetallic aromatic compounds. It is one of the few examples in which the ferrocenyl units are either single bonded or 1,2-substituted to give rise to planar chirality at three of the ferrocenyl units. Electrochemical studies showed that up to six consecutive ferrocenyl-based redox events are observed. Within in situ spectro-electrochemical measurements of both compounds it is shown that two intervalence charge-transfer pathways are possible. At different excitation energies either a charge transfer through the peripheric ethylene bridging unit or through the central benzene unit occurs.

Hydrolysis of either Bi(HSal4Me)3 (A) or [Bi22O26(HSal4Me)14](B) in dmso gave the 4-methylsalicylate-substituted bismuth oxido cluster [Bi38O45(HSal4Me)24(dmso)14(H2O)2]·4H2O (1·4H2O), which crystallizes in the triclinic space group P with cell parameters of a = 20.7214(5), b = 20.9654(6), c = 22.2128(6) A, α = 100.867(2), β = 114.108(2), γ = 107.895(2)° and V = 7815.1(4) A3. The hydrolysis of A was studied by using 1H DOSY NMR spectroscopy and electrospray ionization Fourier-transform ion-cyclotron-resonance (ESI-FTICR) mass spectrometry, both of which showed the formation of several larger species under ambient conditions in the presence of moisture. Furthermore, ESI-FTICR MS analysis of cluster B showed the formation of mainly {Bi23O26} species, which indicates the partial dissociation of cluster B in solution. In addition, the three different bismuth species containing 1 (A), 22 (B) or 38 (1·4H2O) bismuth atoms per molecular formula were tested for their microbiological activity against three strains of Helicobacter pylori (251, 26695 and B128). A minimum inhibitory concentration (MIC) of 6.25 μg mL–1 for the mononuclear bismuth complex A was obtained, whereas the bismuth oxido cluster B showed a lower activity with MIC values in the range 25–50.0 μg mL–1. The activity of 1·4H2O is comparable to commercial remedies based on antimicrobial bismuth subsalicylate (BSS; 12.5 μg mL–1).

The synthesis of 3,4-diferrocenyl-substituted pyrroles of the type 3,4-Fc2-cC4H2NR [Fc = Fe(η5-C5H4)(η5-C5H5); R = Ph (3a), SO2-4-MeC6H4 (Ts) (3b), SiiPr3 (3c)], 3,4-(FcC≡C)2-cC4H2NR [R = Ph (4a), Ts (4b)], and 3-Br-4-FcC≡C-cC4H2NR [R = Ph (7a), Ts (7b)] from 3,4-Br2-cC4H2NR [R = Ph (2a), Ts (2b), SiiPr3 (2c)] is discussed. The molecular structures of 3a,b, 5, 4b, and 7b in the solid state are reported and show that the formal double bonds in the heterocyclic core are rather localized relative to pyrrole itself. The investigations with (spectro)electrochemical methods reveal the different capabilities for the formation of mixed-valent species and allows the classification of 3a,b as class II systems, whereas compounds that feature electron-withdrawing –C≡C– units (4a,b) can be assigned to class I systems according to Robin and Day.

Hydrolysis of bismuth(III) nitrate in the presence of sodium benzoate (NaOBz) in dimethyl sulfoxide (DMSO) gave the bismuth oxido cluster [{Bi38O45(NO3)20(OBz)4(DMSO)24}·4DMSO][{Bi38O45(NO3)24(DMSO)26}·4DMSO] (1), which crystallizes in the monoclinic space group P21/c with cell parameters of a = 35.8728(12) A, b = 20.2750(5) A, c = 34.8624(11) A, and β = 111.797(4)°. The asymmetric unit contains two crystallographically independent bismuth oxido clusters of different composition. Because of the distinct structural relationship of this type of bismuth oxido clusters with the photocatalytically active polymorph β-Bi2O3, colloidal suspensions of nanoscaled 1 as well as colloids composed of the recently reported clusters [Bi6O4(OH)4(NO3)6]·H2O (2), [{Bi38O45(NO3)24(DMSO)26}·2DMSO][{Bi38O45(NO3)24(DMSO)24}·0.5DMSO] (3), and [Bi38O45(OMc)24(DMSO)9]·2DMSO·7H2O (4) were probed for their photocatalytic activity. The bismuth oxido cluster 3 decomposes more than 85 % of a 1 × 10–5 M aqueous solution of rhodamine B (RhB) under visible-light irradiation within 150 min. Colloids of such clusters might serve as model compounds for indirect photodegradation processes of organic contaminants at the metal oxide surface.

New 6,6′-dibromo- and 6,6′-bis(dimethylamino)-substituted 2,2′-diphosphanylbiphenyl ligands 11–14 were prepared starting from 2,2′-dibromo-4,4′-dimethyl-6,6′-dinitro-1,1′-biphenyl (4). Depending on the phosphane groups [diphenylphosphanyl (11, 13) or diisopropylphosphanyl (12, 14)] the palladium dichloride complexes show different coordination symmetry. Whereas the smaller diphenylphosphanyl groups lead to C2-symmetric complexes, the respective bis(diisopropyl)phosphanes 12 and 14 form C1-symmetric complexes that show fluxional behavior due to the restricted rotation of the isopropyl groups as well as the exchange of atom positions within the C1-symmetric conformer. All complexes have been tested as precatalysts in the Suzuki–Miyaura cross coupling reaction of 2-bromotoluene and phenylboronic acid. The activity of the catalytic system increases with the size of the diphosphanes and the donating ability of the ligand. In contrast to C2-symmetric palladium complex 15, platinum complex 19 was found to be C1-symmetric in the solid state despite the fact that both complexes have the small bis(diphenylphosphanyl)-substituted diphosphane ligand 11 in common. NiBr2 adduct 20 with a similar diphosphane 13 exists as a mixture of distorted square-planar and tetrahedral coordination sphere geometries in equilibrium with each other.

A novel synthetic route based on [4+2] cycloaddition for dibromobenzobarrelene derivatives starting from in situ generated 3,5-dibromo-1,2-didehydrobenzene and mesitylene, 1,2,4,5-tetramethylbenzene, 1,2,3,5-tetramethylbenzene, pentamethylbenzene, 1,3-dimethoxybenzene, and 2,4,6-trimethylbromobenzene, respectively, was developed. Thus, six novel dibromobenzobarrelenes with diverse substitution patterns at the barrelene framework including chiral derivatives are reported. The benzobarrelene 6,8-dibromo-1,3,10-trimethyl-1,4-dihydro-1,4-ethenonaphthalene (1a) was functionalized at the annulated benzene ring to give three novel carboxylic acids and two novel phosphonic acid esters. Selected benzobarrelene complexes with RhICl were tested for their catalytic activity in the 1,4-addition of phenylboronic acid towards cyclohex-2-enone. Turnover frequencies up to 3405 h–1 were observed, which are among the highest reported so far for Rh–diene complexes in this type of C–C coupling reaction.

The synthesis of a series of carbosilanes of type 1-Br–C6H4–4-SiMe3–n(CH2CH=CH2)n (n = 1, 2, 3), Si[C6H4–4-SiMe3–n(CH2CH=CH2)n]4, 1-Br–C6H4-4-Si[C6H4–4-SiMe3–n(CH2CH=CH2)n]3 (n = 0, 1, 2, 3), ClSi[C6H4–4-Si{C6H4–4-SiMe3–n(CH2CH=CH2)n}3]3, Si[C6H4–4-Si{C6H4–4-SiMe3–n(CH2CH=CH2)n}3]4 (n = 1, 2), and 1-Br–C6H4–4-Si[C6H4–4-Si{C6H4–4-SiMe3–n(CH2CH=CH2)n}3]3 (n = 0, 1, 2, 3) is discussed. The structures of Si[C6H4–4-SiMe2(CH2CH=CH2)]4 (7b) and ClSi[C6H4–4-Si{C6H4–4-SiMe2(CH2CH=CH2)}3]3 (10a) in the solid state are reported. The crystal structures of both dendrimers are based on C–H···πCC (πCC = double bond of the CH=CH2 groups) and π–π interactions. The 3D network structure observed for 7b is composed of three crystallographically independent head-to-head stacking columns along the crystallographic b axis with π–π contacts among the C6H4 groups of neighboring molecules, with the columns interacting further by C–H···πCC arrangements. Two molecules of 10a interdigitate in the solid state to form self-complementary dimers that are stabilized by C–H···πCC and π–π contacts. The structures of the monomer and the dimer were optimized by using the MM+ force field as implemented in HyperChem 4.02. In addition, the presence of self-complementary structures in solution is evidenced from 1H NMR spectroscopy. In dichloromethane solely dimeric species exist, whereas in benzene monomers are observed. Calculated electrostatic potentials were used to rationalize the supramolecular structures of these two carbosilane compounds.

The hydrolysis of [Bi6O4(OH)4(NO3)6]·H2O (1) in the presence of sodium alkylsulfonates gave the oxidobismuth sulfonates [{Bi38O45(C4H7SO3)8(NO3)14(dmso)19.5(H2O)2}][{Bi38O45(C4H7SO3)10(NO3)16(dmso)16(H2O)2}]·3H2O·3dmso (2, dmso = dimethyl sulfoxide), [Bi38O45(C6H13SO3)14(NO3)10(dmso)28] (3), and [Bi38O45(C8H17SO3)16(NO3)8(dmso)12] (4) upon crystallization from dmso. Compound 2 is the first example of a nanoscaled oxidobismuth cluster that is composed of both an anionic (charge 2–) and a cationic (charge 2+) fragment in the solid state. The clusters were characterized by elemental analysis, ESI mass spectrometry, IR and NMR spectroscopy, as well as thermal analysis. Crystals obtained for 2 were suitable for single-crystal structure analysis.

Consecutive synthesis methodologies for the preparation of a series of trimethylsilyl and tert-butyl-substituted ruthenocenes of the type Ru(η5-C5H3R1R2)(η5-C5H3R3R4) (2, R1 = SiMe3, R2 = R3 = R4 = H; 3, R1 = R3 = SiMe3, R2 = R4 = H; 4, R1 = R2 = R3 = SiMe3, R4 = H; 5, R1 = R2 = R3 = R4 = SiMe3; 6, R1 = R3 = tBu, R2 = R4 = H; 7, R1 = R3 = tBu, R2 = SiMe3, R4 = H; 8, R1 = R3 = tBu, R2 = R4 = SiMe3) and Ru(η5-2,3-Me2C5H5)(η5-C5H4R) (10, R = tBu; 12, R = SiMe3) are discussed and their use as a MOCVD precursor for the deposition of ruthenium is reported. The molecular structures of 3, 5–8, 10, and 12 in the solid state are reported. The half-open ruthenocenes 10 and 12, which are liquids at ambient temperature, exhibit significantly shorter Ru–centroid (η5-2,3-Me2C5H5) bond lengths in contrast to ruthenocenes 3 and 5–8. The thermal behavior of all ruthenocenes was studied by thermogravimetric analysis showing that they evaporate without decomposition at atmospheric pressure. In addition, vapor pressure measurements were carried out to obtain profound information about the volatility of the synthesized sandwich compounds. The highest vapor pressures were found for 10 and 12. It was observed that the higher the number of SiMe3 groups, the higher the deposition temperature. All compounds were applied as precursors in MOCVD. The depositions on Si/SiO2 targets were carried out in a vertical cold-wall CVD reactor between 633 and 688 K with a flow rate of 50 mL min–1 using nitrogen as the carrier gas and oxygen as the coreactant (50 mL min–1). With the tBu-functionalized ruthenocenes 6 and 10 ruthenium thin films were obtained, while mixed ruthenium/SiO2 layers were formed with 2, 7, 8, and 12. The appropriate layers possess thicknesses between 75–135 nm and are conformal and dense as proven by SEM, EDX spectroscopy, and XPS studies.

A straightforward synthesis methodology for the preparation of rhodium(II) carboxylates [Rh2{O2CCH2(OCH2CH2)2OCH3}4]n (1) and [Rh{μ-O2CCH2(OCH2CH2)2OCH3}2(PPh3)]2 (2) is reported. The ethanol-mediated reduction of RhCl3·3H2O with [K{O2CCH2(OCH2CH2)2OCH3}] produced 1, which on further addition of PPh3 afforded 2. Single-crystal X-ray diffraction studies of 2 were carried out showing a paddlewheel arrangement of the dirhodium(II) tetracarboxylate unit with a Rh–Rh distance of 2.4599(5) A. Compounds 1 and 2 were applied in the formation of rhodium nanoparticles (NPs) using 1,2-ethanediol as reducing reagent and poly(vinylpyrrolidone) (PVP) as capping component. Rhodium NPs with a narrow size distribution (

The synthesis and characterization of a series of metallocenylphosphanes of the type PR2Mc/Se=PR2Mc [Mc = Fc = Fe(η5-C5H4)(η5-C5H5), R = C6H5 (3a/4a), 2-MeC6H4 (3b/4b), c-C4H3O (3c/4c), tBu (3d/4d), c-C6H11 (3e/4e); Mc = Rc = Ru(η5-C5H4)(η5-C5H5), R = C6H5 (6a/7a), 2-MeC6H4 (6b/7b), c-C4H3O (6c/7c), c-C6H11 (6d/7d)] and their palladium complexes [PdCl2(PR2Mc)2] [Mc = Fc, R = C6H5 (9a), 2-MeC6H4 (9b), c-C4H3O (9c), tBu (9d), c-C6H11 (9e); Mc = Rc, R = C6H5 (10a), 2-MeC6H4 (10b), c-C4H3O (10c), c-C6H11 (10d)] is reported. The solid-state structure of 4b confirms the tetrahedrally distorted geometry at phosphorus with the o-tolyl groups indicating steric congestion, which is confirmed by 1H and 13C{1H} NMR spectroscopy. Phosphanes 3, 4, and 9 were characterized by cyclic voltammetry with [N(nBu)4][B(C6F5)4] as the supporting electrolyte. In general, the first oxidation occurs at the phosphane metallocenyl unit(s), although the appropriate Pd complexes are oxidized at more positive potentials. Depending on the phosphane or selenophosphane, follow-up reactions occur, which are discussed. In contrast, the palladium complexes show reversible redox behavior. UV/Vis/NIR spectroelectrochemical studies carried out on 9b indicate an electrostatic interaction between the two terminal ferrocenyl groups. All of the palladium complexes were examined as catalysts in Heck and Suzuki C–C cross-coupling and showed high catalytic activities. These results can be correlated to the electronic (1J) parameters of the selenophosphanes.

The reaction of [Fe(η 5 -C 2 H 4 PPh 2 )(η 5 -C 5 H 4 terpy)] (5; terpy = 2,2':6',2"-terpyridin-4'-yl) with diverse transition-metal compounds including [PtCl 2 (Et 2 S) 2 ], [Pd(cod)X 2 ], [AuCl(tht)], [CuBr], [Mo(CO) 4 (nbd)], and [{RhCl(cod)} 2 ] (X = Cl, Br; tht = tetrahydrothiophene; nbd = norbornadiene; cod = cyclooctadiene) to afford heterobi- and trimetallic complexes and a coordination polymer is reported. The following compounds were prepared: [Fe(η 5 -C 2 H 4 PPh 2 (PtCl 2 (SEt 2 )})(η 5 -C 5 H 4 terpy)] (7), trans-[PtCl 2 {(Ph 2 P-η 5 -C 2 H 4 )(η 5 -C 5 H 4 terpy)-Fe} 2 ] (9), [Fe(η 5 -C 2 H 4 PPh 2 PdCl 2 )(η 5 -C 5 H 4 terpy)] (12), [Fe{η 5 -C 5 H 4 PPh 2 (Cl 3 Pd - )}(η 5 -C 5 H 4 terpy{(dmso) 2 ClNi + })] (14), trans-[PdX 2 {(Ph 2 P-η 5 -C 5 H 4 )(η 5 -C 5 H 4 terpy)Fe} 2 ] (16a, X = Cl; 16b, X = Br), [Mo(CO) 4 {(η 5 -C 5 H 4 PPh 2 )(η 5 -C 5 H 4 terpy)Fe} 2 ] (17), [Fe{η 5 -C 5 H 4 Ph 2 P(CuBr)}(η 5 -C 5 H 4 terpy)] n (19), [Fe(η 5 -C 5 H 4 Ph 2 P(AuCl)}(η 5 -C 5 H 4 terpy)] (22), [Fe(η 5 -C 5 H 4 Ph 2 P-(Rh(cod)Cl})(η 5 -C 5 H 4 terpy)] (23), [Ru({η 5 -C 5 H 4 Ph 2 P(AuCl)}-(η 5 -C 5 H 4 terpy)Fe) 2 ]Cl 2 (25), and [Fe{η 5 -C 5 H 4 PPh 2 -(PdCl 2 )}{η 5 -C 5 H 4 -CH=CHC(O)(py)}] (26). The molecular structures of 5, 9, 12, 14, 16b, 22, and 26 in the solid state are reported. They show typical features of related phosphanyl-ferrocenes and terpyridylferrocenes. Characteristic of 12 is a C-H activation as a result of the close distance of palladium to the terpyridyl moiety. Complexes 12, 26, and [PdCl 2 (dppf)] [dppf = 1,1'-bis(diphenylphosphanyl)ferrocene], for comparison, were used in preliminary studies as catalysts in the carbon-carbon coupling of iodobenzene with tert-butyl acrylate to give (E)-tert-butyl cinnamate. The conversion amounts to 80 % with a turnover number of 160 and turnover frequency of 48 h -1 .

The synthesis and reaction chemistry of heteromultimetallic transition-metal complexes are discussed. Complex [(η 2 -dppf)(η 5 -C5H5)Ru-C=C-C6H4-4-PPh 2 ] (3) [dppf = 1,1'-bis(diphenylphosphanyl)ferrocene], accessible by treating [(η 2 -dppf)(η 5 -C 5 H 5 )RuCl] (1) with equimolar amounts of HC≡C-C 6 H 4 -4-PPh 2 (2), gives on treatment with [(cod)RhCl] 2 (4), [(η 5 -C 5 Me 5 )RhCl 2 ] 2 (6), and [(tht)AuCl] (8) heterotrimetallic [(η 2 -dppf)(η 5 -C5H5)Ru-C≡C-C6H4-4-PPh 2 -{Rh}] [5, {Rh} = (cod)RhCl; 7, {Rh} = (η 5 -C 5 Me 5 )RhCl 2 ) and [(η 2 -dppf)(η 5 -C 5 H 5 )Ru-C≡C-C 6 H 4 -4-PPh2-AuCl] (9), respectively. Tetra-and even pentametallic heteronuclear complexes can be prepared by following consecutive reaction sequences: Treatment of 9 with HC≡CR {10a, R = C 5 H 4 N-4; lOb, R = C 6 H 4 -4-C=N; lOc, R = bpy (= 2,2'-bipyridyl-5-yl); 12a, R = bpy[-Re(CO) 3 Cl]} in the presence of HNEt 2 and [Cul] gave [(η 2 -dppf)(η 5 -C5H5)Ru-C≡C-C6H4-4-PPh2-Au-C≡CR] {11a, R = C 5 H 4 N-4; lib, R = C 6 H 4 -4-C≡N; 11c, R = bpy; 13, R = bpy-[Re(CO) 3 Cl]}. Compound 11c is the key starting material for complexes of higher nuclearity. Treatment of 11c with [(nbd)-Mo(CO) 4 ] (14) afforded heterotetrametallic {(η 2 -dppf)(η 5 -C5H5)Ru-C=C-C6H4-4-PPh2-Au-C≡C-bpy[Mo(CO)4]) (15), whereas with [{[Ti](μ-σ,π-C≡CSiMe 3 )2)M]X [16a, MX = Cu(N≡CMe)PF 6 ; 16b, MX = AgOClO 3 ] novel heteropentametallic [(η 2 -dppf)(η 5 -C5H5)Ru-C≡C-C6H4-4-PPh2-Au-C≡C-bpy({[Ti](μ-σ,π-C=CSiMe3)2)M)]X (17a, M = Cu, X = PF 6 ; 17b, M = Ag, X = ClO 4 ) is formed. The reaction of lla with [{[Ti](μ-σ,π-C=CSiMe3) 2 }Cu]OTf (16c) produced [(η 2 -dppf)-(η 5 -C 5 H 5 )Ru-C=C-C6H4-4-PPh2-Au-C=C-4-C5H4N({[Ti](μ-σ,π-C=CSiMe3)2)Cu)]OTf (18). The structures of 9, lib, 11c, and 12 in the solid state and the electrochemical behavior of selected complexes are also reported.

The cover picture shows a novel hexanuclear bismuth oxido cluster [Bi6O4(OH)4(OTf)6], which forms a 1D coordination polymer in the solid state but is highly soluble in water and polar organic solvents. The reaction of the bismuth oxido cluster with sodium polyacrylate gave a nano-sized hybrid material still soluble in aqueous solution. A snapshot from a molecular dynamics simulation is shown as an example of the apparent complexation of [Bi6O4(OH)4]6+ by polyacrylate in water. The synthesis and structure of [Bi6O4(OH)4(OTf)6] as well as its complexation with polyacrylate are reported in the article by D. Zahn, M. Mehring et al. on p. 4763 ff.