bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reversibility in the Reaction of Cyclohexadienyl Radicals with Oxygen in Aqueous Solution
Authors: Fang Xingwang , Pan Xianming , Rahmann Anja , Schuchmann Heinz‐Peter , von Sonntag Clemens 
Published: July 2007

AbstractHydroxyl radicals were generated radiolytically and reacted with a number of benzene derivatives (PhH). In the presence of oxygen, the hydroxycyclohexadienyl radicals thus formed were converted into their corresponding peroxyl radicals. Pulse radiolysis has shown the oxygen addition (forward reaction, f) to be reversible (reverse reaction, r) [Eq. (1)]. The peroxyl radicals can eliminate HO to yield phenols, alongside some ring‐fragmentation products (product‐forming reaction, p). The rate constants for the forward and reverse reactions (kf and kr) and the corresponding stability constants K (= kf/kr) were determined for the hydroxy‐cyclohexadienyl radicals derived from anisole, toluene, fluorobenzene, benzene, chlorobenzene, benzyl chloride, benzoate ion, phenylalanine, and terephthalate ion. The constants kf lie between 8 × 108 (anisole) and 1.6 × 107 dm3 mol−1 s−1 (terephthalate ion), and kr between 7.5 × 104 (toluene) and 3.4 × 103 s−1 (terephthalate ion). The stability constants lie between 2.6 × 104 (benzene) and 3.3 × 103 dm3 mol−1 (phenylalanine). The rate constants for the product‐forming reactions kp are between 5.5 × 103 (anisole) and 3.4 × 102 s−1 (benzoate). For the peroxyl radical derived from phenylalanine, a bond dissociation energy of 5.5 kcal mol−1 has been derived. A number of hydroxy‐cyclohexadienyl radicals (e.g., those derived from benzoic acid, ethylbenzoate, benzonitrile, and nitrobenzene) react too slowly to allow the equilibrium constant to be determined by means of pulse radiolysis. These reactions have rate constants kf in the order of 5 × 106 dm3 mol−1 s−1, except for nitrobenzene where the reaction is too slow for measurement. The rate constants kr are below 500 s−1, and the product‐forming reaction is too slow to be detected by pulse radiolysis. γ‐Radiolysis of N2O/O2(4:1)‐saturated aqueous solutions of benzonitrile gave dimeric compounds (e.g., dicyanobiphenyls) in low yield, alongside the three isomeric phenols; this again proves the low reactivity of its hydroxycyclohexadienyl radical toward oxygen.
New PF3 and Carbonyl Chemistry of Tantalum
Authors: Ellis John E. , Warnock Garry F. , Barybin Mikhail V. , Pomije Marie K. 
Published: July 2007

AbstractReduction of [TaCl5] by six equivalents of alkali metal naphthalenide in 1,2‐dimethoxyethane at −60°C followed by treatment with gaseous PF3 provides the first homoleptic phosphane complex containing tantalum in the −1 oxidation state, [Ta(PF3)6]−. This can be protonated by concentrated sulfuric acid to yield the previously unknown highly acidic and volatile hydride [HTa(PF3)6]. An improved normal‐pressure synthesis of [Ta(CO)6]− is described. Reduction of the latter species by sodium in liquid ammonia gives the carbonyl trianion [Ta(CO)5]3− which undergoes monoprotonation and stannylation to form [HTa(CO)5]2− and [Ph3SnTa(CO)5]2−, respectively. The hydride is a useful precursor to [(Ph3PAu)3Ta(CO)5], the only known gold cluster of tantalum.
A Theoretical Model for the Active Site of Nitrogenase
Authors: Stavrev Krassimir K. , Zerner Michael C. 
Published: July 2007

AbstractA model for the active site of nitrogenase is suggested and examined by means of the intermediate neglect of differential overlap (INDO) quantum mechanical method. The initial steps of the nitrogen fixation process are discussed within the framework of the present model, and it is shown that of several binding sites, initial location of the nitrogen molecule inside the MoFe cofactor is favored. Possible pathways for electron and proton delivery to the active site are also suggested on the basis of electrostatic potential calculations.
Aryloxycarbonylcarbene Complexes of Bis(oxazolinyl)pyridineruthenium as Active Intermediates in Asymmetric Catalytic Cyclopropanations
Authors: Park Soon‐Bong , Sakata Naoya , Nishiyama Hisao 
Published: July 2007

AbstractThe reaction of [RuCl2(pybox)‐(C2H4)] (1) (pybox = 2,6‐bis[4′S)‐isopropyloxazolin‐2′‐yl]pyridine) and 2,6‐di‐tert‐butyltolyl diazoacetate (4) (DBT‐DA) in benzene at 50°C gave a stable 2,6‐di‐tert‐butyltolylcarbonylcarbene‐ruthenium complex 5 in 94% yield. The structure of 5 was characterized by NMR spectroscopy. 2,6‐Diisopropylphenyl diazoacetate (6) and 2,4,6‐trimethylphenyl diazoacetate (7) also gave the corresponding carbene complexes 9 and 10, respectively. Asymmetric carbene transfer from the carbene complexes to styrene resulted in formation of the trans isomer of phenylcyclopropanecarboxylates 2 with high enantioselectivity: 2 was obtained as the sole product in 80% yield (55% ee) from 5 at 80 °C and in 82% yield (97% ee) from 9 at 60°C; from 10 at 40°C, a mixture of 2 and 3 in a ratio of 97:3 was formed in 91% yield (97% ee for 2 and 99% ee for 3). After the carbene transfer reaction, the ethylene complex 1 could be regenerated and isolated by treatment of the reaction mixture under an ethylene atmosphere. The carbene complexes 9 and 10 (2 mol%) exhibited catalytic activity in the asymmetric cyclopropanation of styrene with the corresponding diazoacetates.
Heterosupramolecular Chemistry: An Approach to Modulating Function in Molecular Devices
Authors: Marguerettaz Xavier , Redmond Gareth , Nagaraja Rao S. , Fitzmaurice Donald 
Published: July 2007

AbstractLinked viologen‐anthraquinone molecules are attached to TiO2 nanocrystallites supported on a conducting glass substrate. The resulting assembly is incorporated as the working electrode in an electrochemical cell. Under opencircuit conditions, band‐gap excitation of the semiconductor nanocrystallite results in viologen‐mediated electron transfer to anthraquinone. Prior application of a negative potential step, which results in 2e−/2H+ reduction of anthraquinone, permits electron transfer only to viologen. At positive applied potentials, electron transfer following band‐gap excitation is largely suppressed. Some implications of these findings for modulation of function in molecular devices are considered.
Supramolecular Motifs: Concerted Multiple Phenyl Embraces between Ph4P+ Cations Are Attractive and Ubiquitous
Authors: Dance Ian , Scudder Marcia 
Published: July 2007

AbstractExamination of the Cambridge Structural Database reveals that Ph4P+ cations in crystals associate through phenyl‐phenyl nonbonded interactions which are attractive, concerted, and widespread. Intermolecular phenyl‐phenyl conformations, which are offset‐face‐to‐face (off), edge‐to‐face (ef) or vertex‐to face (vf), combine in five classes of supramolecular motifs for {Ph4P+}2 pairs, namely the sextuple phenyl embrace (SPE) with (ef)6 and offset sextuple phenyl embrace (OSPE) containing (off)1 (ef)2(ef/vf)2, the translational quadruple phenyl embrace (TQPE) with (ef)4, the parallel quadruple phenyl embrace (PQPE) with (off)1(vf)2, and the double phenyl embrace (DPE) with (off)1. Typical intermolecular attractive energies (kJ per mol of {Ph4P+}2) for these motifs are SPE 85, OSPE 57, TQPE 70, PQPE 41, DPE 34. There is strong interpenetration of the cations in these motifs: 489/770 structures in the CSD have P ⃛P≤7 Å (spherical Ph4P+ has a van der Waals diameter of 13.6 Å). Of the 812 instances of P ⃛P ≤7 Å, 86% are SPE, 10% are OSPE, 2% are TQPE, and only 2% are unclassified, Average P ⃛P separations in the PQPE and DPE are 8.3 Å. Centrosymmetry is prevalent in all except the TQPE, which has implications for the engineering of noncentric crystals.
Separation of Diastereomeric and Enantiomeric Alkyl Nitrates–Systematic Approach to Chiral Discrimination on Cyclodextrin LIPODEX‐D
Authors: Schneider Manfred , Ballschmiter Karlheinz 
Published: July 2007

AbstractHigh‐resolution gas chromatographic separation of all diastereomeric monomethyl‐substituted cyclohexyl nitrates is shown on a nonpolar methylpolysiloxane stationary phase, and the first application of this procedure to the environmental diastereomeric analysis of alkyl nitrates is presented. Two characteristic signals in the achiral analysis of atmospheric samples could be assigned to the smallest alkyl nitrate containing two asymmetric carbon atoms, 3‐methyl‐2‐pentyl nitrate. Retention indices in the temperature‐programmed separation based on the n‐alkanes were determined. The homologous series of 1‐alkyl nitrates were found to be useful as ECD‐visible n‐alkanes. Enantiomeric separation of alkyl nitrates was achieved on heptakis(3‐O‐acetyl,‐2,6‐di‐O‐pentyl)‐β‐cyclodextrin (LIPODEX‐D). The influence of the nitrooxy group and the alkyl chain length on the chiral discrimination on LIPODEX‐D is discussed for 25 chiral alkyl nitrates. The absolute configurations of some alkyl nitrates were assigned by asymmetric synthesis of enantiomerically pure references. The complexity of the alkyl nitrate mixtures present in air samples does not allow a direct chiral separation as the alkyl nitrates partly coelute on the LIPODEX‐D column. Column coupling of LIPODEX‐D with a polar achiral stationary phase like polyalkylenglycol (PAG) was successfully applied to solve this problem, and the chiral alkyl nitrates present in a typical air sample were separated. A systematic nomenclature for alkyl nitrates is introduced to handle the steadily growing number of branched and long‐chain alkyl nitrates detected in environmental analysis.
Hydrogen, the First Alkali Metal
Authors: Hensel Friedrich , Edwards Peter P. 
Published: July 2007

AbstractWe examine the density‐dependent metal‐nonmetal transition (MNMT) for the Group 1 elements hydrogen, rubidium and caesium. Remarkably, the experimentally observed metallization densities agree closely with those predicted from the 1927 classical theory of K. F. Herzfeld, which outlines the critical conditions necessary for the metallization of any element of the periodic system. The metallization densities of the alkali metal elements are also consistent with the quantum mechanical theory of the MNMT, as first set out by Sir Nevill Mott.
Preparation, Characterization, and Reactivity of a Diamagnetic Vanadium Nitride
Authors: Song Jae‐Inh , Gambarotta Sandro 
Published: July 2007

AbstractThe reactions of (Ph2N)3V‐(THF) (1) with [(CH3)3Si]N3 and [(CH3)3Si]CHN2 proceed at room temperature to afford the corresponding derivatives (Ph2N)3V[N‐Si(CH3)3] (2a) and (Ph2N)3V[N2CHSi(CH3)3] (3). Reactions of both 2a and 3 with lithium isopropylamide provide the unprecedented anionic vanadium nitride species [(Ph2N)3V(μ‐N)Li(THF)3]·(THF)0.5 (4), which displays moderate nucleophilicity. It reacts with (CH3)3SiCl and Mel to reform the complex (Ph2N)3V(N‐R) [R = Si(CH3)3 (2a), Me (2b)]. Reactions with Cp2ZrCl2 and CpTiCl3 lead to the formation of the heterodinuclear bridged nitride complexes [(Ph2N)3V(μ‐N)ZrClCp]2] [Cp = Cp]=Cp (6a), CH3C5H4 (6b)] and [{(Ph2N)3V(μ‐N)}2TiClCp] (8).
Coordination Arrays: Synthesis and Characterisation of Rack‐Type Dinuclear Complexes
Authors: Hanan Garry S. , Arana Claudia R. , Lehn Jean‐Marie , Baum Gerhard , Fenske Dieter 
Published: July 2007

AbstractA series of mono‐ and dimetallic complexes of rack type containing a dinucleating bis‐tridentate ligand and RuII‐2,2′:6′,2′‐terpyridyl (tpy) sites were synthesised and characterised. The 1H NMR spectra of the dimetallic complexes were correlated to structural features, and the crystal structures of the dimetallic complexes were determined. They provide information about the way in which the central substitutent affects the overall shape of the racks and the relative disposition of the metal centres, measured by the pinching angle of the bis‐tridentate ligand and the convergence angle of the ancillary tpy units. The latter demonstrates that a CH3 group yields the least bent complex and indicates how parallel the tpy units are. The dimetallic racks exhibit metal‐metal interactions mediated by the bis‐tridentate ligands as indicated by electrochemical and spectroscopic methods. The bridging‐ligand π* orbital and the dπ metal orbital are stabilised by complexation of a second metal. The results obtained provide guidelines for the design of extended racks bearing several metal centres in a linear arrangement, which also represent potential components of molecular electronic devices.
Cesium Fluoride–Bromine Intercalation Compounds
Authors: Drews Thomas , Marx Ruppert , Seppelt Konrad 
Published: July 2007

AbstractCsF reacts with Br2 to form the two intercalation compounds CsF·Br2 and 2CsF·Br2. The former consists of layers of CsF squares separated by layers of Br2 molecules oriented perpendicular to the CsF layers. 2CsF·Br2 is a second‐stage compound, composed of two layers of CsF followed by one layer of bromine molecules. Iodine cannot replace bromine; instead, it reacts with CsF to form Cs2I8, and probably CsIF6 between 0° and 120 °C. Chlorine does not react at all with CsF. Bromine reacts with RbF only superficially, and after a long time some RbBr3 is observed; RbF and I2 give RbI3.
Anionic Glucophospholipids—A New Family of Tubule‐Forming Amphiphiles
Authors: Giulieri Françoise , Guillod Frédéric , Greiner Jacques , Krafft Marie‐Pierre , Riess Jean G. 
Published: July 2007

AbstractA new family of amphiphiles that form tubules (i.e., hollow cylindrical bilayer‐based microstructures) by self‐aggregation has been identified, namely, anionic glucophospholipids of type 1, in which a double‐tailed hydrophobe is grafted through a phosphate linkage to the O‐6 position of a polar glucose head group. Compounds 1a‐c self‐assemble into stable, hollow tubular microstructures when dispersed in water and cooled below the temperature at which the transition between crystal and liquid‐crystal phases takes place (estimated from change in turbidity). The diameter of the microstructures appears to depend on the nature of the hydrophobic tail, significantly smaller diameters being obtained for fluorinated tails. No tubules were obtained when galactose (2a‐c, pH<11) or mannose (3a‐c) derivatives were used instead of glucose derivatives, or when glucose was derivatized at the O‐3 (4b) rather than O‐6 position; in these cases only vesicles were formed. Tubules made of 1 converted rapidly into giant vesicles when heated; they spontaneously formed again upon cooling. The presence of a fluorinated chain, as in 1b and 1c, increased the temperature at which the tubule‐vesicle interconversion occurred to above room temperature. Because the amphiphiles are negatively charged, the formation of tubules is pH‐dependent and is favored at higher pH. These findings support the view that hydration of and hydrogen bonds between polar heads play a major role in tubule formation. Hydration of the sugar‐derived head groups decreases as the number of intermolecular hydrogen bonds increases; this favors membrane crystallization and tubule formation.
Investigation of the Self‐Assembly Pathway of Pentanuclear Helicates by Electrospray Mass Spectrometry
Authors: Marquis‐Rigault Annie , Dupont‐Gervais Annick , Van Dorsselaer Alain , Lehn Jean‐Marie 
Published: July 2007

AbstractThe self‐assembly of the pentanuclear double helicates Hh, Ha and He from the corresponding oligobipyridine strands Lh, La and Le and Cu1 ions has been investigated by NMR and electrospray mass spectrometry (ESMS). Where as Hh is assembled rapidly (in less than 20 min), He (about 20 h) and especially Ha (about 60 h) form much more slowly. The rate decreases strongly with increasing steric bulk of the substituents in the 4,4′‐positions on the bipyridine units; this indicates that the search processes (wrapping, unwrapping) that lead to the final helicate are strongly hindered by the size of the substituents. The ESMS data give information about the species present in solution under different conditions and allow the formulation of possible formation pathways, which may involve, in particular, helicates of hairpin type.
A Novel Type of Resonance‐Stabilised Dicobalt Complex with a Cyclopentadienylidene Bridge—Synthesis, Structure and Electronic Properties of [(C5R5)Co(μ‐C5H4)Co(L)(C5R5)'] (L = C2H4, CO, CNtBu, PR3, P(OMe)3; R = H, Me)
Authors: Wadepohl Hubert , Galm Wolfgang , Pritzkow Hans , Wolf Andreas 
Published: July 2007

AbstractThe dinuclear μ‐cyclopentadienylidene complexes [(C5R5)Co(μ‐C5H4)‐Co(C2H4)(C5R'5)] (5) [5aa (R = R' = H), 5ab (R = H, R' = Me), 5ac (R = H, R'5 = H4Me), 5ba (R = Me, R' = H), 5bb (R = R' = Me) and 5da (R5 = Me4Et, R' = H)] were synthesised from [(C5R5)Co(η4‐C5H6)] (4) [4a (R = H), 4b (R = Me), 4d (R5 = Me4Et)] and [(C5R'5)Co(C2H4)2] (1) [1a (R' = H), 1b (R' = Me) and 1c (R'5 = H4Me)]. In these reactions, both CH bonds of the methylene group of coordinated cyclopentadiene are activated under mild conditions. Substitution of the ethylene ligand in 5 by L leads to the carbonyl, isocyanide, phosphine, and phosphite derivatives [(C5R5)Co(μ‐C5H4)Co(L)‐(C5R'5)] [6aa, 6ab, 6ba, 6bb (L = CO), 7aa (L = tBuNC), 8aa, 8ab (L = PMe3), 9aa (L = PMe2Ph), 10aa (L = PMePh2) and 11aa (L = P(OMe)3)]. The crystal structures of 5aa, 5ab, 5ba, 6aa and 8aa have been determined. The experimental geometry is rationalised in terms of two limiting structures with μ‐η4:η1 and μ‐η5:η1 coordination of the bridging cyclopentadienylidene ligand. On the basis of the 18 valence electron rule, zwitterionic character is assigned to latter. This structure is preferred when L is an acceptor ligand, as in 6. In solution, 5–11 are fluxional with rapid rotation about the very short cobalt–carbene C bond. In addition the hindered rotation of the ethylene ligand in 5ab was studied by DNMR spectroscopy. In solution, a singlet‐triplet equilibrium was established by variable‐temperature NMR spectroscopy for 8aa. The temperature‐dependent 1H NMR line shifts were analysed by means of an isotropic shift model to give 24≤ΔH° ≤ 32 kJ mol‐1 and 45≤ΔS° ≤74 J mol‐1 K‐1 with the triplet state being preferred by entropy at higher temperatures.
Regiochemistry of Twofold Additions to [6,6] Bonds in C60: Influence of the Addend‐Independent Cage Distortion in 1,2‐Monoadducts
Authors: Djojo Francis , Herzog Andrea , Lamparth Iris , Hampel Frank , Hirsch Andreas 
Published: July 2007

AbstractThree series of regioisomeric bisadducts of C60, namely, C62(anisyl)4 and the mixed systems C62(anisyl)2‐(COOEt)2, and C61(COOEt)2(NCOOEt), were synthesized starting from the 1,2‐monoadducts C61(COOEt)2 (1), C61‐(anisyl)2 (2), and C60(NCOOEt) (4) by using the Bingel and Bamford‐Stevens reactions, and nitrene additions. In the case of C61(COOEt)2(NCOOEt) the complete series of nine possible regioisomers were isolated for the first time. For steric reasons the cis‐1 isomers of C62(anisyl)4 and C62(anisyl)2(COOEt)2 were not formed. The transannular [6,6] bonds in the cis‐1 isomer 42 of C61(COOEt)2(NCOOEt) are closed. The properties and regioselectivities of formation of these bisadducts and their monoadduct precursors were compared with those of the series C62‐(COOEt)4 and C60(NCOOEt)2, which we synthesized previously. In the additions to 1, 2, and 4 the preferred positions of attack are e and trans‐3 for sterically demanding addends (e.g., combinations of C(anisyl)2 and C(COOEt)2) and cis‐1, e, and trans‐3 for sterically less demanding addends (e.g., combinations of N(COOEt) and C(COOEt)2). A detailed analysis of the MO structures, the experimental and calculated geometries of monoadduct precursors, and the stabilities of reaction products leads to the conclusion that the addend‐independent cage distortion itself is responsible for the observed regioselectivities of bisadduct formations.
Ab Initio Models for the Nitroaldol (Henry) Reaction
Authors: Lecea Begoña , Arrieta Ana , Morao Iñaki , Cossío Fernando P. 
Published: July 2007

AbstractAb initio calculations (up to MP4SDQ/6‐31+G*//MP2(FU)/6‐31+G*+ δZPVE) on several model nitroaldol (Henry) reactions have been performed. It is found that the free nitronate anions react with aldehydes via transition states in which the nitro and carbonyl dipoles are antiperiplanar to each other. This kind of reaction yieldsanti (erythro)nitroalcohols as major products. The Henry reaction between lithium nitronates and aldehydes is predicted to occur via cyclic transition structures yieldingsynnitroalcohols as major products. The stereocontrol in these model reactions is low. The factors affecting the stereoselectivity in the reaction between dilithiated nitronates and aldehydes are also discussed.
Novel inorganic cage structures based on ass ligands and cyclopentadienylruthenium groups
Authors: Brunner Henri , Nuber Bernhard , Poll Ludwig , Roidl Gaby , Wachter Joachim 
Published: July 2007

AbstractThe reaction of [Cp(*)2Ru2‐(CO)4] [a: Cp(*) = Cp* (η5‐C5Me5); b: Cp(*) = Cpx (η5‐C5Me4Et)] with β‐realgar in boiling n‐decane gives [Cp(*)2Ru2‐As4S4] (1a,b). in good yields along with some [Cp(*)2Ru2‐As4S2] (2a,b). According to X‐ray diffraction analyses of 1b and 2a, their structures belong to two different types of inorganic clusters. Whereas 1b has a cage structure in which the [Cp(*)2Ru2 unit is inserted into the As4S4] cradle, 2a has a sandwich structure in which two coplanar η2‐As4S ligands and the Cp* ligands are oriented parallel to one another. Analysis of the As‐S connectivity in the core of 1 b reveals a structural relationship to the extremely rare form of arsenic sulfide As4S4(II), and not to the metastable high‐temperature form β‐As4S4 used in the synthesis. At lower temperatures (60, 115°C) formation of CO‐containing products is observed.
The Vinylketene‐Acylallene Rearrangement: Theory and Experiment
Authors: Bibas Hervé , Wong Ming Wah , Wentrup Curt 
Published: July 2007

AbstractAlkoxyvinylketenes4are generated by flash vacuum thermolysis (FVT) or photolysis of 3‐alkoxycyclobutenones3. The thermal interconversion of4and allene carboxylic acid esters5under FVT conditions is demonstrated by Ar matrix FTIR spectroscopy. In addition, ethoxy‐vinylketene4bundergoes thermal elimination of ethene with formation ofs‐cis‐ands‐trans‐acetylketene(8). An analogous aminovinylketene‐to‐allenecarbox‐amide conversion is observed on FVT of 3‐dimethylaminocyclobutenone3c. A facile 1, 3‐chlorine migration in 2, 3‐buta‐dienoyl chloride(5d)is also reported. Consistent with the experimental observations, 1, 3‐methoxy, 1, 3‐chloro, and 1, 3‐dimethylamino migrations in vinylketene are calculated (G2(MP2, SVP) level) to have moderate barriers of 169, 157, and 129 kJ mol−1, respectively, significantly less than the corresponding 1, 3‐H shift barrier (273 kJ mol−1). The stabilization of the four‐center transition structures is rationalized in terms of the donor‐acceptor interaction between the lone pair electrons of the migrating donor substituent and the vacant central carbon p orbital of the ketene LUMO. The predicted migratory aptitude in the series of substituted vinylketenes, R‐C(CH2)‐CHCO, is in the order N(CH3)2>SCH3>SH>Cl>NH2>OCH3>OH>F>H>CH3, and correlates well with the electron‐donating ability of the R group.
Nitridosilicates‐A Significant Extension of Silicate Chemistry
Authors: Schnick Wolfgang , Huppertz Hubert 
Published: July 2007

AbstractBecause of its low chemical reactivity Si3N4 has hardly been used as a starting material for the preparation of multinary silicon nitrides or nitridosilicates, but has gained increasing importance as a nonoxidic material for high‐performance applications. A novel synthetic approach is presented, which starts from silicon diimide (Si(NH)2) and makes available a large variety of novel nitridosilicates. The structures of these nitridosilicates represent a significant extension from those found in the family of oxosilicates. Because of their outstanding chemical and physical stability, nitridosilicates might be of particular interest for the development of novel inorganic nitridic materials.