bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of Zaragozic Acid A/Squalestatin S1
Authors: Nicolaou K. C. , Yue Eddy W. , la Greca Susan , Nadin Alan , Yang Zhen , Leresche James E. , Tsuri Tatsuo , Naniwa Yoshimitsu , de Riccardis Francesco 
Published: July 2007

AbstractA novel synthetic approach to the construction of the zaragozic acids, which was used for the asymmetric synthesis of zaragozic acid A/squalestatin S1 (1), is described. Fragment 5, representing the tricarboxylic acid core portion, is assembled in three key steps: 1) Stille coupling to establish the carbon framework; 2) enantioselective dihydroxylation to introduce the absolute stereochemistry; and 3) diastereoselective dihydroxylation to complete the required carbon‐oxygen connectivity. The convergency of this synthesis is demonstrated by the dithiane addition of a variety of C 1 side chains (e.g., 78) to advanced intermediate 5. A multi‐event acid‐catalyzed rearrangement yielded the zaragozic acid core 86, which was converted to an intermediate obtained from degradation of zaragozic acid A. A second‐generation synthesis of the core of the zaragozic acids is also described. When aldehyde 90 was used instead of 5, both the yield and diastereoselectivity of the dithiane addition reaction were improved, although the degree of convergency was slightly lower.
Synthesis of (R)‐tert‐Leucinol by Classical Resolution of the Racemic Mixture
Authors: Drauz Karlheinz , Jahn Wilfried , Schwarm Michael 
Published: July 2007

AbstractOptically active tert‐leucinol is an important building block in asymmetric synthesis. However, the (R) enantiomer particularly has so far remained difficult to obtain, mainly because of the laborious synthesis of the precursor amino acid, (R)‐tert‐leucine. Here we present a new, classical resolution of racemic tert‐leucinol, which allows straightforward preparation of each, but especially the (R) enantiomer, in good yields and high optical purities. The feasibility of the synthesis of useful derivatives is demonstrated by transformation into the corresponding (R)‐4‐tert‐butyl‐2‐oxazolidinone.
The Reduction of [Fe(CO)2L2X2] (L = P(OMe)3, P(OiPr)3, PEt3; X = Br, I)—From Iron(II) to Iron(0) via Stable Iron(I) Intermediates
Authors: Kandler Helmut , Gauss Christine , Bidell Wolfgang , Rosenberger Stephan , Bürgi Tobias , Eremenko Igor L. , Veghini Dario , Orama Olli , Burger Peter , Berke Heinz 
Published: July 2007

AbstractThe reduction of [Fe(CO)2‐L2X2] (L = P(OMe)3X = Br (1a), I (1b); L = P(OiPr)3, X = Br (2a), I (2b); L = PEt3, X = Br (3a), I (3b)) with Zn in dioxane (1a,b‐2a,b) or PhLi in ether (3a,b) led to formation of the corresponding dicarbonyl(halo)bis(phosphorus donor)iron(I) complexes (L = P(OMe)3, X = Br (4a), I (4b); L = P(OiPr)3, X = Br (5a), I (5b); L = PEt3, X = Br (6a), I (6b)). Slightly contaminated5a,band pure6a,bwere isolated as stable crystalline blue or blue‐green complexes. Complexes4a,bwere obtained, with only minor impurities, by comproportionation of1a,band the dicarbonyl(halo)bis‐(trimethylphosphite)ferrate anions7a,band characterized in THF solution. The comproportionation products5a,b‐6a,bwere obtained in high yields by reaction of2a,b‐3a,bwith the dinitrogen complexes13‐15. Further reduction of4a,b‐6a,bor exhaustive reduction of1a,b‐3a,bwith sodium amalgam oriBuLi in THF afforded the nonisolable dicarbonyl‐(halo)bis(phosphorus donor)ferrate(o) anions (7a,b‐9a,b). The latter were characterized by acidification with trifluoroacetic acid or acetic acid yielding stable dicarbonyl (halo) hydridobis (phosphorus donor)iron(II) complexes (L = P(OMe)3, X = Br (10a), I (10b); L = P(OiPr)3, X = Br (11a), I (11b);L = PEt3, X = Br (12a), I (12b)). In the presence of N2,8awas transformed into dinitrogen complex [Fe(CO)2{P(OiPr)3}2N2] (13). With9a,bthe reaction led to formation of [Fe‐(CO)2(PEt3)2)2N2] (14) and [{Fe(CO)2‐(PEt3)2}2(μ‐N2)] (15). In solution at low temperature (−90 to 0°C), the dinitrogen complexes14and15are in equilibrium with each other. Complexes13, 14, and15were characterized by IR,1H,13C,31P, and15N NMR spectroscopy. The structures of5a, 6b, 14, and15were determined by X‐ray diffraction studies.
A Novel Low Molecular Weight Chiral Gelator for Apolar Organic Solvents
Authors: Snijder Carina S. , de Jong Johannes C. , Meetsma Auke , van Bolhuis Fré , Feringa Ben L. 
Published: July 2007

AbstractThe synthesis, molecular structure, and properties of a new chiral gelforming agent 1 are described. Key structural features in 1 are a γ‐alkoxybutyro‐lactone tetralin moiety and an angular phenylsulphone unit. The new low molecular weight gelator 1 can reversibly form stable gels in low concentrations (e.g., 1:800 for n‐hexane) with isopropanol and a variety of apolar organic solvents. The gels were studied with differential scanning calorimetry and a combination of electron microscopy techniques, which revealed a highly ordered three‐dimensional network of entangled fibers. X‐ray analysis showed that the aggregation of 1 leads to a helical structure in the solid state. Nonchiral analogues 2 and 3 were unable to initiate gel formation.
Synthesis and Molecular Structure of the First Neutral Transition‐Metal Complex Containing a Linear MCCCCCR2 chain
Authors: Lass Raimund W. , Steinert Paul , Wolf Justin , Werner Helmut 
Published: July 2007

AbstractThe reaction of [IrH2Cl(PiPr3)2] (2) with the pentadiyne derivative HCCCCCPh2OH (1) yields the five‐coordinate compound [IrH(CCCCPh2OH)Cl(PiPr3)2] (3), which photochemically rearranges to give the vinylidene‐substituted isomer trans‐[IrCl(CCH‐CCPh2OH)(PiPr3)2] (4). On treatment of 3 with pyridine, the octahedral complex [IrH (CCCCPh2OH)Cl(py)(PiPr3)2] (5) is formed. While attempts to eliminate water from 4 (or 5) failed, the reaction of 3 with one equivalent of trifluorosulfonic acid anhydride and two equivalents of triethylamine led to the formation of trans‐[IrCl(CCCCCPh2)(PiPr3)2] (6), which is the first neutral transition‐metal complex containing a C5R2 ligand. The X‐ray structural analysis of 6 reveals a perfect square‐planar coordination geometry around the metal centre and an almost linear IrC5 chain with Ir‐CC and CCC bond angles of 174–179°.
Pulled Molecular Strings and Stacked Molecular Decks: Chelate‐Ring Formation vs. Metal–Metal Bridging in Dicopper(I) Complexes of 2,2′‐Bipyrimidine with Diphosphine Ligands of Variable Polymethylene Chain Length
Authors: Schwach Manuela , Hausen H.‐D. , Kaim Wolfgang 
Published: July 2007

AbstractThe “self‐assembly” reaction between bischelating 2,2′‐bipyrimidine, metallic copper, Cu2+, and two equivalents of bidentate Ph2P(CH2)nPPh2 produces crystallographically characterized dinuclear complexes with a [Cu1(μ‐bpym)‐Cu1]2+ core and chelating (n = 5; type I) or bridging diphosphine ligands (n = 6, 8; type II). Structures II may be designated as “inverse cryptate” arrangements. The structural data of the solids and the spectroscopic results for the dissolved species indicate a strained configuration in the case of complex [(μ‐bpym)Cu2{μ‐Ph2P‐(CH2)n]2+ (6) with n = 6. Once the polymethylene chain length is reduced one notch further to n = 5 (5), the diphosphines can no longer bridge but help to form eight‐membered chelate rings (structure I). In this complex there is a distortion towards a trigonal‐pyramidal coordination geometry at the copper(I) centers, which is supported by the formation of an “organic sandwich” arrangement between the central bpym acceptor and two phosphino phenyl rings.
Electron‐poor 2,3‐Dihydro‐1,3‐Diborolyl Complexes of Iron and Ruthenium: Synthesis, Reactivity, and Crystal and Electronic Structures of an Iron Sandwich Complex
Authors: Hettrich Ralph , Kaschke Michael , Wadepohl Hubert , Weinmann Wolfgang , Stephan Martin , Pritzkow Hans , Siebert Walter , Hyla‐Kryspin Isabella , Gleiter Rolf 
Published: July 2007

AbstractThe addition product of sodium hydride and the 2,3‐dihydro‐1,3‐diborole (CiPr)2(BEt)2CHMe (3c) reacted with [{(C5Me5)FeCl}x] to produce the green sandwich complex [(C5Me5)Fe{n5‐(CiPr)2(BEt)2CMe}] (2 c), which formally contains 16 valence electrons (VE). Complex 2c has unexpected structural properties in the solid state: the 1,3‐diborolyl ring is extremely folded (41°), and the Fe–C2 distance is short (1.90 Å). Analogously, violet Ru complexes 4a,c,d were obtained from 3a,c, NaH or tBuLi, and [{(C5Me5)RuCl}4]. With the less bulky heterocycles 3 b,e the new 30 VE triple‐decker complexes [(C5Me5)Ru{μ,n5‐(CR1)2(BR2)2CMe}RuH(C5Me5)] (5b,e) were formed, which contain a Ru–H bond. Cyclic voltammetric studies revealed the existence of stable anions 2c‐ and 4d‐ formed by reversible one‐electron reduction at –1.26 and –1.40 V, respectively (vs. SCE). The red‐brown anions were further characterized by ESR spectroscopy following stepwise reduction of the neutral species with potassium in THF. Addition of CO to 4a and 4d led to formation of the monocarbonyl complexes [(C5Me5)Ru(CO){n5‐(CR1)2‐(BR2)2CMe}] (6a,d), and 6d was characterized by X‐ray structure analysis. The heterocycle in 6d is less folded (19°) than in 2 c. Its CO ligand causes a 28.5° tilt of the cyclic ligands. Reaction of CO with 2 c yielded a red product of unknown structure. The electronic structure of 2 was studied by EH‐MO theory, which revealed a unique bonding in the sandwich. The s̀ electron density of the B–C bonds participates in the bonding to the iron atom; this demonstrates that the number of bonding electrons is the same as in ferrocene. Thus, the complexes 2 actually have 18 VE.
C‐Disaccharides of Ketoses
Authors: Streicher Hansjörg , Geyer Armin , Schmidt Richard R. 
Published: July 2007

AbstractReaction of gluconolactone2with allylmagnesium bromide at low temperatures afforded ketopyranose3, which could easily be converted into open‐chain ketoses (R)‐6and (S)‐6. Their reaction with lithioacetylide9afforded propargylic alcohol derivatives (R)‐10and (S)‐10, which could not be cyclized directly to the desiredC‐ketosides. They were converted by standard procedures into (R)‐14and (S)‐14and then into dicobalthexacarbonyl complexes (R)‐16and (S)‐16. A facile acid‐catalyzed ring closure gave the desiredC‐ketosides (R)‐18α/βand (S)‐18α/β, respectively, in different ratios. In order to demonstrate that removal of the protective groups and hydrogenation of the CC triple bond proceed smoothly, (R)‐18α was transformed into the deprotected target molecule (R)‐1α. For the assignment of the new chiral centers at C‐2/2′ and at C‐8, (S)‐18α was transformed into azido derivative (S)‐22α, which underwent intramolecular cycloaddition to afford the spiro derivative (S)‐25α. Because of the conformational constraints in this molecule, unequivocal configurational assignment was possible with the help of NMR data.
The Pagodane → Dodecahedrane Concept–Shorter Routes, Higher Yields
Authors: Bertau Martin , Leonhardt Jürgen , Weiler Andreas , Weber Klaus , Prinzbach Horst 
Published: July 2007

AbstractTwo variants of the “SN2 route” from pagodanes (A, B) to functionalized dodecahedranes (D, F) and particularly dodecahedradienes (E) offer considerable improvements in the number of operations (from nine to five to three) and yields (e.g., for diesterFfrom 55–65 to 70–75 to 85–91%). Key steps are the regio‐ and stereospecific introduction of four to six bromine substituents into dimethyl pagodane‐4‐syn,9‐syn‐dicarboxylate (1 b) and a highly complex (thirteen bond‐breaking/bond‐forming events in four participating structures). yet very convenient (one‐pot operation) and extremely efficient (nearly quantitative) transformation of secopagodane to bissecododecahedradiene with complete stereocontrol in transannular CH2functionalizations. The prohibitively low kinetic acidity of “caged” hydrogens has so far only been overcome with the recently reported P2F reagent (Schwesinger). Further improvement of the overall economy of the pagodane → dodecahedrane scheme has been achieved by efficiently channeling a byproduct of the pagodane synthesis (ca. 10%) back into the SN2 track.
Permethyltitanocene Derivatives with Naked Chalcogen Ligands: Synthesis of [(Cp*2Ti)2(μ‐E)] and [Cp*2Ti(μ2‐E2)] and the Role of the Terminal Chalcogenides [Cp*2Ti(E)] in Their Interconversion (E = Se, Te)
Authors: Piers Warren E. , Ziegler Tom , Fischer Jason M. , Macgillivray Leonard R. , Zaworotko Michael J. 
Published: July 2007

AbstractPermethyltitanocene hydride, [Cp*2TiH], reacts with elemental selenium or tellurium to give the products [(Cp*2Ti)2(μ‐E)] (E = Se, 1a Te, 1b), [Cp*2Ti(μ2‐E2)] (E = Se, 2a; Te, 2b) and [Cp*2Ti(μ2‐Se3)] (3), depending on the equivalency of the chalcogen employed. Dinuclear compounds 1 are paramagnetic and have D2d (idealized) structures, as shown by X‐ray structural analysis of μ‐telluride 1b; they may be converted to diamagnetic dichalcogenides 2 through further reaction with the appropriate chalcogen. Derivatives 2 are monomeric in the solid state, as shown by X‐ray structural analysis of ditelluride 2b, and in solution, as demonstrated by multinuclear NMR spectroscopy. Combination of diselenide 2a and ditelluride 2b results in partial redistribution to the mixed species [Cp*2Ti(μ2‐SeTe)], suggesting dimeric structures of formula [Cp*2Ti(μ‐E‐E)2 TiCp*2] may be accessible in solution. The dichalcogenides and the triselenide may be converted back to complexes 1 by treatment with a chalcogen‐abstracting agent. The possible involvement of monomeric terminal chalcogenides [Cp*2Ti(E)] in the interconversion of 1 and 2 was probed experimentally and computationally by means of Density Functional Theory calculations on [Cp2M(E)] (M = Ti, E = O, S, Se, Te; M = Zr, E = O, Te). Several unsuccessful attempts to generate and trap [Cp*2Ti(Te)] are described. The results of these studies suggest that [Cp*2Ti(Te)] has a very weak Ti–Te bond and a readily accessible triplet excited state. These factors, along with the small size of titanium, render this member of the [Cp*2M(E)] family of complexes difficult to trap with Lewis bases, in contrast to many other congeners in the series of Group 4 terminal chalcogenides.
Triazidogallium and Derivatives: New Precursors to Thin Films and Nanoparticles of GaN
Authors: Fischer Roland A. , Miehr Alexander , Herdtweck Eberhardt , Mattner Michael R. , Ambacher Oliver , Metzger Thomas , Born Eberhard , Weinkauf Sevil , Pulham Colin R. , Parsons Simon 
Published: July 2007

AbstractThe synthesis and properties of [Ga(N3)3]∞ (1) and the related derivatives [(Do)nGa(N3)3] (2a‐d: Do = THF, NEt3, NMe3, quinuclidine, n = 1; 2e: Do = pyridine; n = 3), Li[(CH3)Ga(N3)3] (3), [(N3)2Ga{(CH2)3NMe2}] (4), [Cp(CO)2‐Fe‐Ga(N3)2(py)] (5), and [(CO)4Co‐Ga(N3)2(NMe3)] (6) are reported. Compounds 2e and 4 were characterized by single‐crystal X‐ray diffraction. The deposition of polycrystalline GaN thin films from 2a‐e by solution methods (spin‐on pyrolysis) and the solid‐state pyrolysis of 1 to give GaN nanoparticles are described.
A Paradigm Case for the Merging of Glycal and Enzymatic Assembly Methods in Glycoconjugate Synthesis: A Highly Efficient Chemo‐Enzymatic Synthesis of GM3
Authors: Liu Kevin K.‐C. , Danishefsky Samuel J. 
Published: July 2007

AbstractA concise, regio‐ and stereoselective synthesis of the ganglioside GM3 has been achieved. Use of an α‐1,2‐oxirane derived from lactal facilitated installation of the anomeric β‐ceramide side chain. Introduction of the sialic acid residue at C3, of the lactose was accomplished regiospecifically by enzymatically mediated sialyl transfer from CMP‐Neu‐5‐Ac.
Photochemistry of N‐Phthaloylcysteine Derivatives: Multiplicity‐Directed Regioselective CH Activation
Authors: Griesbeck Axel G. , Hirt Joachim , Peters Karl , Peters Eva‐Maria , von Schnering Hans Georg 
Published: July 2007

AbstractThe photochemistry of the methyl esters of N‐phthaloylcysteine derivatives 1b–5b was studied. The results are remarkable, because they prove a pronounced, multiplicity‐controlled regioselectivity of the initial CH activation step. From substrates 1b–4b the benzazepine‐1,5‐dione 6 was produced exclusively by the singlet path. The formation of compound 6 is initiated by a γ‐H abstraction; this was demonstrated by deuterium labeling experiments. The penicillamine derivative 5b was unreactive in the singlet manifold. From substrates 1b–3b and 5b the thiazinoisoindoles 7–9 and 11 were produced exclusively by the triplet path. The sterically hindered S‐isopropylcysteine derivative 4b also furnished this product type (10) as a proportion of the products in the singlet manifold. These annulation products result from a primary photoinduced electron‐transfer (PET) step followed by heterolytic ϵ‐H activation. The mechanistic scenario was elucidated by quenching and sensitization experiments. An interplay of CH activation steps and electron back‐transfer is probably responsible for this type of spin selectivity.
Concave Hydrocarbons
Authors: Gross Jens , Harder Gabriele , Siepen Astrid , Harren Jörg , Vögtle Fritz , Stephan Holger , Gloe Karsten , Ahlers Benedikt , Cammann Karl , Rissanen Kari 
Published: July 2007

AbstractConcave hydrocarbons, such as 1 (C36H36), 4 (C60H60), 5 (C54H48), and 6 (C60H52), represent three‐dimensionally clamped analogues of π‐prismands. They encapsulate small metal ions and accomplish metal‐ion extraction from aqueous solution. Their remarkable selectivity allows applications such as incorporation in ion‐selective electrodes. The synthetic route is based on well‐established cyclophane methodology and, thus, offers a general approach to a whole family of concave hydrocarbons.
Heterocyclic Carbenes: A High‐Yielding Synthesis of Novel, Functionalized N‐Heterocyclic Carbenes in Liquid Ammonia
Authors: Herrmann Wolfgang A. , Köcher Christian , Gooßen Lukas J. , Artus Georg R. J. 
Published: July 2007

AbstractTo date the only free carbenes of the imidazoline‐2‐ylidene type to have been described in the literature are those bearing simple hydrocarbon or haloalkyl and ‐aryl substituents. We report here a novel, versatile and high‐yielding method for the synthesis of N‐heterocyclic carbenes in a mixture of liquid ammonia and aprotic organic solvents. Deprotonation of the imidazolium precursor salts proceeds under mild conditions within a few minutes at temperatures below –30°C, and side reactions are thus avoided. The imidazolium salts are much more soluble in organic solvents if liquid ammonia is added. Furthermore, the acidity of the C‐2 protons appears to be enhanced by hydrogen bonding. Not only are the known free ylidenes conveniently and quantitatively accessible by this procedure, but also novel functionalized derivatives that are not accessible by known procedures. Imidazoline‐2‐ylidenes with linear, branched, cyclic, heteroatom‐substituted (O, N, P) and chiral hydrocarbon residues are accessible through the novel route. Stable carbene‐metal “adducts” are conveniently obtained by treating the free carbenes with chloro‐ or acetato‐bridged dinuclear metal complexes, or by displacement of coordinated ligands such as carbon monoxide, THF or acetonitrile by the free carbenes. The syntheses of novel imidazolium salts. N‐heterocyclic carbenes and carbene adducts of RuII, RHI, W0 and sulfur are reported, and the structures of five products analysed by single‐crystal X‐ray diffraction. N‐Heterocyclic carbenes bearing functionalized side chains are important because a number of these complexes show excellent activity in catalytic reactions. They do not show the typical reactivity of metal‐carbon “double bonds” and are remarkably stable both thermally and chemically. For a number of reasons, they are best viewed as donor adducts of the highly Lewis basic imidazoline‐2‐ylidene ligands and the Lewis acidic organometallic fragments. The new synthetic procedure reported here makes N‐heterocylic carbenes a generally accessible class of useful ligands in coordination chemistry and catalysis.
Synthesis, Structure, and Reactions of the First Rotational Isomers of Stable Thiobenzaldehydes, 2,4,6‐Tris[bis(trimethylsilyl)methyl]thiobenzaldehydes
Authors: Takeda Nobuhiro , Tokitoh Norihiro , Okazaki Renji 
Published: July 2007

AbstractThe first rotational isomers of thiobenzaldehydes, TbtCHS (2a and 2b; Tbt = 2,4,6‐tris[bis(trimethylsilyl)methyl]phenyl), were synthesized and isolated as stable crystalline compounds by the desulfurization of the corresponding overcrowded cyclic polysulfides TbtCHSn (n = 5 or 8) with phosphine reagents. The molecular structures of 2a and 2b in the solid state, determined by X‐ray crystallographic analysis, differed in their conformations, which were essentially identical with those in solution as revealed by 1H{1H} nuclear Overhauser effect (NOE) experiments. The isomeric thiobenzaldehydes 2a and 2b were found to undergo thermal interconversion. A kinetic study of this process gave reasonable kinetic and thermodynamic parameters for conformational isomerizations of this type. Interesting differences in reactivity among the two isomers 2a,b and 2,4,6‐tri‐tert‐butylthiobenzaldehyde (1) were shown in the reactions with hydrazine and m‐chloroperoxybenzoic acid.
The Thiazole Ylide: A Frequently Invoked Intermediate Is a Stable Species in the Gas Phase
Authors: McGibbon Graham A. , Hrušák Jan , Lavorato David J. , Schwarz Helmut , Terlouw Johan K. 
Published: July 2007

AbstractThe 1, 2‐hydrogen shift isomers of neutral (singlet and triplet) thiazole (1) and its radical cation have been investigated by a combination of mass spectro‐metric experiments and hybrid density functional theory calculations. The latter were used to probe the structures and stabilities of selected C3H3NS and C3H3NS.+ isomers and transition state structures. Although 3H‐thiazole‐2‐ylidene (2) is less stable than 1, by 31.5 kcalmol−1, it is expected to be capable of independent existence, since the 1, 2‐hydrogen shift from carbon to nitrogen involves a very large energy barrier of 72.4 kcalmol−1. The other 1, 2‐hydrogen shift reaction from C(2) leads not to the expected cyclic 1H‐thiazole‐2‐ylidene structure (3), which is apparently unstable, but rather to the ring‐opened species HSCHCHNC (4), which is 34.5 kcalmol−1 higher in energy than 1. The barrier in this case is lower but still large (54.9 kcalmol−1). The triplet ground states of 1, 2 and 4 are considerably destabilised (69.5, 63.2 and 58.7 kcalmol−1) relative to their singlet states. Interestingly, in addition to 2.+ and 4.+, the cyclic radical cation 3.+ is predicted to be stable although it is substantially higher in energy than ionised thiazole 1.+ (by 53.9 kcalmol−1), whereas 2.+ and 4.+ are much closer in energy (only 10.2 and 27.0 kcalmol−1 higher, respectively). Dissuading 2.+ and 3.+ from isomerising to 1.+ are energy barriers of 52.6 and 15.3 kcalmol−1, respectively. Experimentally, dissociative ionisation of 2‐acetylthiazole enabled the generation of 2.+, which could be differentiated from 1.+ by collisional activation mass spectrometry. Reduction of the ylide ion 2.+ in neutralisation‐reionisation mass spectrometry experiments yielded the corresponding neutral molecule 2. This direct observation of a thiazolium ylide provides support for postulates of such species as discrete intermediates in a variety of biochemical transformations.
Edge‐sharing SiN4 Tetrahedra in the Highly Condensed Nitridosilicate BaSi7N10
Authors: Huppertz Hubert , Schnick Wolfgang 
Published: July 2007

AbstractThe novel nitridosilicate BaSi7N10 was obtained by the reaction of barium metal with Si(NH)2 in a special high‐frequency furnace at 1650 °C. The single‐crystal structure determination (a = 687.29(3), b = 671.29(3), c = 963.28(4) pm, β = 106.269(3)°, PC, Z = 2, R1 = 0.0497, wR2 = 0.0924) reveals a network structure of connected SiN4 tetrahedra. BaSi7N10 is the first nitridosilicate with both corner and edge‐sharing SiN4 tetrahedra. Unlike the situation in normal oxosilicates, vertex‐sharing of SiN4 tetrahedra is not exclusively favored over edge‐sharing. With a Si:N molar ratio of 7:10, BaSi7N10 is the most highly condensed multinary nitridosilicate known and has almost the same degree of condensation as binary Si3N4.