bluuebunny/crossref_metadata_2025_split huggingface dataset:
Metallkomplexe in Anorganischen Matrices, 8[1] Chromtricarbonyl‐Komplexe von Benzoylacetonat‐substituierten Titan‐, Zirkonium‐ und Aluminium‐Alkoxiden
Authors: Schubert Ulrich , Buhler Hermann , Hirle Brigitte 
Published: July 2007

Metal Complexes in Inorganic Matrices, 8[1]. – Chromium Tricarbonyl Complexes of Benzoylacetonate‐Substituted Titanium‐, Zirconium‐, and Aluminium Alkoxides*Benzoylacetone (bzac‐H) reacts with one equivalent of Al(OtBu)3 or Zr(OPr)4 to give the mono‐substituted compounds (bzac)Al(OtBu)2 (1b) and (bzac)Zr(OPr)3 (1a), while with one equivalent of Ti(OtBu)4 or Zr(OtBu)4 the bis‐substituted derivatives (bzac)2Ti(OtBu)2 (3c) and (bzac)2Zr(OtBu)2 (3d) are obtained. Upon heating in dibutyl ether, 1b disproportionates into (bzac)2Al(OtBu) (3b) and Al(OtBu)3. Thermal reaction of 1a, 3b, and 3c with Cr(CO)6 leads to metal complexes having a Cr(CO)3 moiety π‐bonded to the phenyl group of the benzoylacetonate ligand.
Alkoxygermanate(II), ‐stannate(II) und ‐plumbate(II) zweiwertiger Metall‐Ionen, II. Verbindungen des Formeltyps M2El2(OtBu)8
Authors: Veith Michael , Käfer Dieter , Koch Jürgen , May Peter , Stahl Lothar , Huch Volker 
Published: July 2007

Alkoxygermanates(II), ‐stannates(II), and ‐plumbates(II) of Divalent Metal Ions, II[1]. – Compounds of the Formula M2El2(OtBu)8By simple salt‐exchange processes the starting materials Na2El2(OtBu)6 (El = Ge, Sn, Pb) can be transformed to germanates, stannates and plumbates of divalent magnesium and divalent transition metals. Two types of compounds are formed in these reactions: MEl2(OtBu)6 [El = Ge, M = Mg (1A), Cr (1B), Mn (1C), Zn (1F); El = Pb, M = Mn (3C), M = Zn (3F)] and M2El2(OtBu)8 [El = Ge, M = Co (1d), Ni (1e); El = Sn, M = Mg (2a), Cr (2b), Mn (2c), Co (2d), Ni (2e); El = Pb, M = Co (3d)]. Single‐crystal X‐ray diffraction studies have been performed on 1C, 1d, 2a, 2b, 2c, 2d, and 2e, and the structures have been solved. In 1C the Mn atom occupies the center of an elongated O6 octahedron, the germanium(II) atoms displaying pyramidal coordination by three oxygen atoms. The central molecular cage can be described as two MnO3Ge trigonal bipyramids sharing the common central Mn atom and being wrapped by tert‐butyl groups linked to the oxygen atoms. The other compounds of the MEl2(OtBu)6 formula seem to be isostructural with the exception of 3F, which displays a 1H‐NMR spectrum which is not compatible with this structure. All X‐ray structures of the compounds M2El2(OtBu)8 show the same feature: to a central M2(OtBu)2 four‐membered ring are spirocyclically connected two M(OtBu)2El rings through the common metal atoms M. The structure is completed by the coordination of an exocyclic tert‐butoxy group to the terminal El atoms. The metal atoms M are therefore quasi tetrahedrally coordinated while the Ge and Sn atoms are in pyramidal threefold oxygen atom environments. All molecules display an El ⃛M ⃛M ⃛El one‐dimensional arrangement. From susceptibility measurements it is apparent, that in the compounds MEl2(OtBu)6 and M2El2(OtBu)8 the transition metal atoms are in high‐spin configurations, which is also supported by the UV spectra. Analysis of the structural data of the series 2a–2e reveal important contributions of the electronic environments of the transition metal atoms to the M ⃛M and M ⃛Sn distances. A qualitative MO description is used to explain these features. Again it has been shown that the, „geometrical softness”︁ of Ge(OtBu)3 and Pb(OtBu)3 is greater than of Sn(OtBu)3, as the former two can accomodate Cr2+ and Mn2+ in a sixfold coordination site by two units, while Sn(OtBu)3 coordinates Cr2+ and Mn2+ with only two alkoxy groups. When 1C and 2d are allowed to react with nonacarbonyldiiron Mn‐Ge2(OtBu)6 · 2 Fe(CO)4 (4) and Co2Sn2(OtBu)8 · 2 Fe(CO)4 (5), respectively, are formed. Compound 4 displays presumably five metal atoms in a linear arrangement while 5 has six metallic elements arranged in one dimension. The latter fact has been unambigously proved by an X‐ray structure determination.
Addition von Silylenen an Iminoborane
Authors: Paetzold Peter , Hahnfeld Detlef , Englert Ulli , Wojnowski Wieslaw , Dreczewski Boguslaw , Pawelec Zbigniew , Walz Leonhard 
Published: July 2007

Addition of Silylenes to Iminoboranes[1]Photolytically generated silylenes SiMe2 and SiMes2 are treated with iminoboranes XBNtBu [X = tBu, Me3Si(tBu)N, iPr2N: 1a–c]. The products from SiMe2 and 1a are the four‐and six‐membered rings [–B(tBu)=N(tBu)–SiMe2–SiMe2–] (3a) and [–B(tBu)N(tBu)B(tBu)magnified imageN(tBu)–SiMe2–SiMe2–] (4a), depending on the conditions of the photolysis. SiMe2 reacts with 1b to give the six‐membered ring [–BX=N(tBu)–SiMe2–BX=N(tBu)–SiMe2–] (4b). From SiMes2 and 1a,c the three‐membered rings [–BX=N(tBu)–SiMes2–] are formed (2a: space group Pbca; 2c: space group Pmagnified image1): SiMes2 reacts with 1b to yield the unexpected four‐membered BNSiN ring [magnified imageB(Mes)magnified imageN(tBu)–Si(Mes)(SiMe3)–N(tBu)magnified image] (5: space group Pmagnified image1).
Addition von Stannylenen an Iminoborane
Authors: Paetzold Peter , Hahnfeld Detlef , Englert Ulli 
Published: July 2007

Addition of Stannylenes to IminoboranesIminoboranes tBuB  NR (R = tBu, Mes: 1 a, b) undergo aminostannation by the diaminostannylene Sn[N(SiMe3)2]2 (2b) to give (Me3Si)2N‐B(tBu) = NR–Sn–N(SiMe3)2 (4a, b). The stannylene 4 b remains monomeric in the crystal (space group P21/n). The cyclic diaminostannylene [–Sn–N(tBu)–SiMe2‐N(tBu)–] (3 b), instead, simply adds the boranes 1 a, b across one of its Sn–N bonds to form the bicyclo[2.2.0]hexene‐type products 5a, b.
Umlagerungen von Bicyclo[3.2.1]oct‐2‐en‐6‐yl‐ und Benzobicyclo[3.2.1]octenyl‐Kationen
Authors: Kirmse Wolfgang , Mönch Dietmar 
Published: July 2007

Rearrangement of Bicyclo[3.2.1]oct‐2‐en‐6‐yl and Benzobicyclo[3.2.1]octenyl CationsThe ketones 9, 27, and 51 were prepared by modified or novel routes. The analogous tosylhydrazones 10, 28, and 52 were photolyzed in 0.5 N NaOH (NaOD) to generate the carbocations 15, 34, and 53, respectively, by way of diazonium precursors. 2,3‐Unsaturation (15) and 2,3‐benzoanellation (34) affected the course of 4,6‐(4,5‐)hydride shifts, as elucidated by deuterium labeling. While the parent system 3 strongly prefers C‐5 over C‐6 (95:5) as the terminus of hydride shifts, 15 and 34 (55:45) approach the equivalence of C‐5 and C‐6 that is indicative of rapid Wagner‐Meerwein rearrangements or symmetrically bridged intermediates. This trend is attributed to flattening of the six‐membered ring in 15 and 24, as compared to the chair conformation of 3. On the other hand, predominant nucleophilic substitution at C‐6 is unaffected by 2,3‐unsaturation. We suggest that s̀ participation (kΔ) by alkyl groups is not sufficient to eliminate inverting displacement of nitrogen from the diazonium precursors by the solvent (ks). Equivalence of C‐5 and C‐6 toward external nucleophiles is achieved only by π participation, i.e. with the 3,4‐unsaturated and 3,4‐benzoanellated bicyclo[3.2.1]oct‐6‐yl systems (53).
Diastereo‐ and enantioselective synthesis of 1,2:5,6‐diepoxy‐4‐hydroxyalkyl carbamates. – regioselective ring opening and their transformation into doubly C‐branched deoxy sugar analogues
Authors: Peschke Bernd , Lüßmann Jörg , Hoppe Dieter , Dyrbusch Zzmichael 
Published: July 2007

AbstractEnantiomerically enriched (Z)‐anti‐3,5‐dialkyl‐4‐hydroxy‐1,5‐alkadienyl N,N‐diisopropylcarbamates 12, readily obtained by the homoaldol approach, were oxidized with essentially complete diastereoselectivity to afford 1,2:5,6‐diepoxides 14 of D‐allo configuration. Conditions were worked out for the transformation of 14 into furanosides of types 19, 21, and 22 and for the selective nucleophilic introduction of carbon residues into the 6‐position to give chain‐elongated analogues 25. Altogether, a “brick‐box system” for the enantioselective construction of polystereogenic building blocks with a few synthetic steps from simple achiral starting materials [(E)‐2‐alkenyl carbamates of type 9 and 2‐alkyl‐2‐alkenals (11)] and nucleophiles, like Grignard reagents, is demonstrated.
Photoelectron Spectrum and Electronic Structure of Indigo
Authors: Rademacher Paul , Kowski Klaus 
Published: July 2007

AbstractThe He(I) photoelectron spectrum of indigo has been obtained by evaporating the compound at ca. 400°C. The ionization potentials are related to orbital energies or electronic states of the radical cation with the aid of semi‐empirical SCF‐MO calculations. A satisfactory interpretation of the spectrum up to 18 eV is obtained according to the HAM/3 method.
Enthalogenierung von Aminodihalogenboranen durch Na/K‐Legierung in Gegenwart von Naphthalin, Bis(trimethylsilyl)butadiin und 2,5‐Dimethyl‐2,4‐hexadien
Authors: Maringgele Walter , Knop Henning , Bromm Dietmar , Meller Anton , Dielkus Sven , Herbst‐Irmer Regine , Sheldrick George M. 
Published: July 2007

Dehalogenation of Aminodihalogenoboranes by Na/K Alloy in the Presence of Naphthalene, Bis(trimethylsilyl)butadiyne, and 2,5‐Dimethyl‐2,4‐hexadieneReaction of naphthalene with Na/K alloy and [(2,6‐diisopropylphenyl)methylamino]difluoroborane (1) in 1,2‐dimethoxyethane yields the aminodimethoxyborane 2, the bis(amino)‐borane 3, the diborylethyne 4, and the diboryl oxide 5. By addition of a mixture of bis(trimethylsilyl)butadiyne or 2,5‐dimethyl‐2,4‐hexadiene with dichloro(diisopropylamino)borane to Na/K alloy in hexane the 2,4,5‐triborabicyclo‐[1.1.1]pentane 7 and the diboretane 8, resp., are obtained. 1H‐, 11B‐, 13C‐, 19F‐, 29Si‐NMR‐, IR, and MS data are given. For 2–4, 7 and 8 X‐ray structure analyses are performed.
Die Fluorsulfine XF2C(F)C  SO (X = F, Cl, Br), ihre Synthese und ungewöhnliche Zersetzungsart
Authors: Gradel Jan , Sundermeyer Wolfgang 
Published: July 2007

The Fluorosulfines XF2C(F)C  SO (X = F, Cl, Br), Their Synthesis and Unusual Type of DecompositionA new route for the synthesis of the sulfenyl chloride 3 opens an easy access to fluoro(trifluoromethyl)sulfine (6) by hydrolysis of 3, trapping 6 by Diels‐Alder reaction with anthracene, and thermolysis of the formed compound 8. By addition of the thioacetyl fluorides XF2C(F)C  S (X = Cl, Br) to anthracene compounds 9a, b are obtained, which could be oxidized to the sulfene adducts 12a, b as well as to the sulfine adducts 13a, b. Thermolysis of the latter yields the sulfines 17a, b, which are unstable at room temperature. A second approach to 17a involves oxidation of 1,3‐dithietane 11a to its S‐oxide 14a (e.g. via an S,S‐difluoro compound 15a) and subsequent thermolysis, but thermal decomposition predominates. An unusual decomposition has been observed for 17a, b which was hitherto unknown for sulfines.
Synthesis and Diels‐Alder Reactions of 1,2‐Dimethylene‐ and 1,2,9,10‐Tetramethylene[2.2]paracyclophane: New Routes to Bridge‐Anellated [2.2]Paracyclophanedienes
Authors: König Burkhard , Meijere Armin De 
Published: July 2007

AbstractThe title compounds 8 and 1 have been synthesized in three steps each from 1,2‐dibromo[2.2]paracyclophan‐1‐ene (2) and 1,2,9,10‐tetrabromo[2.2]paracyclophane‐1,9‐diene (4), respectively. Copper‐mediated coupling of vinyl bromides 2 and 4 with methyl‐ and phenylmagnesium bromide gives substituted [2.2]paracyclophanes 3‐CH3, 3‐Ph, 5‐CH3, and 5‐Ph in good yields. The high reactivity of the [2.2]paracyclophane‐1,2‐dimethylene moieties in 8 and 1 in Diels‐Alder reactions has been verified in cycloadditions with p‐benzoquinone to give 10 and 13 and with naphthalene 1,4‐endoxide to yield 12.
Mehrstufige reversible Redoxsysteme, LIX. Leitfähige Charge‐Transfer‐Komplexe von 2,5‐Bis(cyanimino)‐2,5‐dihydrothieno[3,2‐b]thiophenen mit organischen Donoren
Authors: Günther Erhard , Hünig Siegfried , Schütz Jost‐Ulrich Von , Langohr Uwe , Rieder Harald , Söderholm Svante , Werner Hans‐Peter , Peters Karl , Schnering Hans Georg Von , Lindner Hans Jörg 
Published: July 2007

Conducting Charge‐Transfer Complexes of 2,5‐Bis(cyanoimino)‐2,5‐dihydrothieno[3,2‐b]thiophenes with Organic DonorsFrom the title compound 4 and several donors 13 charge‐transfer (CT) complexes have been obtained. Most of them show powder conductivities of 0.01–2.0 Scm−1. The crystal structure of 4d/TTF (20 Scm−1) reveals segregated stacks of donor and acceptor molecules in a novel stacking pattern. The structure of 4d/TMTSF consists of mixed stacks (insulator), however a second phase (no structure available) exhibits very high conductivity (200 Scm−1).
Neue Synthesen und Reaktionen von Phosphetaniumsalzen mit planarem Gerüst
Authors: Brauer David J. , Ciccu Antonella J. , Heßler Gisbert , Stelzer Othmar 
Published: July 2007

Novel Syntheses and Reactions of Phosphetanium Salts with a Planar magnified image SkeletonCleavage of the P–Si bond of silylphosphanes R2P‐SiMe3 (R = iPr, tBu, 2,4,6‐Me3C6H2) with excess 1,3‐dihalogenpropanes X–[CH2]3–X (X = Br, I) affords phosphetanium salts magnified image (3) in good yields. These strained four‐membered ring systems are also obtained by alkylation of secondary phosphanes R2PH with X–[CH2]3–X followed by deprotonation of the intermediate phosphonium salts [R2P(H)—[CH2]3–X]+ X‐ (R e.g. tBu; X = Br, 7b). Silylphosphanes and secondary phosphanes with less bulky substituents preferably form open‐chain phosphonium salts with [CH2]3–X or allyl substituents in these reactions. X‐ray structural analysis of magnified image (3h) reveals planar geometries for the PC3 skeletons of the cations. The reactivity of 3b towards different types of nucleophiles [F‐, NH2‐, OH‐, OR‐, Fe(CO)2Cp‐, NaN(SiMe3)2, RR′PLi] has been studied. Reaction with CsF or NaNH2, leads to a stable monofluoro or monoamino phosphorane, respectively, with cyclic four‐membered PC3 skeletons. In all other cases opening of the phosphetanium ring system occurs leading to derivatives with R2P—[CH2]3 terminal groups. Bidentate and polydentate ligands, e.g. 19–25, with bulky substituents in terminal position have been synthesized in high yields by cleavage of 3b with mono‐ and bifunctional lithium phosphides. By deprotonation of 3b with MeLi the cyclic ylide 14 is formed. Treatment with acetone or benzaldehyde leads to the unsaturated open‐chain phosphane oxides 15a or 15b in a Wittig‐type reaction.
Cycloadditionsreaktionen von Phosphenium‐Metallkomplexen, 2. Cyclisierte Phosphiniden(metallo)phosphorane durch Addition von, „Methylphosphiniden”︁ an Phosphenium‐ und Arsenium‐Wolframkomplexe
Authors: Malisch Wolfgang , Hindahl Kathrin , Schemm Rudolf 
Published: July 2007

Cycloaddition Reactions with Phosphenium Metal Complexes, 2. – Cyclized Phosphinidene(metallo)phosphoranes by Addition of “Methylphosphinidene” to Phosphenium and Arsenium Tungsten ComplexesCyclized phosphinidene(metallo)phosphoranesmagnified image(3a, b, 5) are obtained from Cp(OC)2W = ER2(E = P, As; R =tBu,oTol)(1a, b, 4) and (MeP)5(2). Treatment of3awith CH3I yields the cationic η2‐diphosphane complexmagnified image(6). The reaction of3bwith elemental sulfur and selenium leads to the four‐membered metallacyclesmagnified image(X = S, Se) (7a, b).
Asymmetrische Katalyse, 67. Diastereoselektive Hydrierung der Folsäure mit optisch aktiven Rhodium(I)‐Diphosphan‐Komplexen
Authors: Brunner Henri , Huber Christian 
Published: July 2007

Asymmetric Catalysis, 67[1]. – Diastereoselective Hydrogenation of Folic Acid with Optically Active Rhodium(I)‐Diphosphane ComplexesWith immobilized rhodium(I)‐diphosphane catalysts supported on silica gel, the C = N bonds of the pyrazine ring of folic acid (1) are reduced with hydrogen in aqueous solution to give 5,6,7,8‐tetrahydrofolic acid. A mixture of the two diastereomers 2a and 3a is obtained with (6S)‐ and (6R)‐configuration, respectively, at the newly formed asymmetric center in the pterine system and (S)‐configuration in the L‐glutamic acid moiety. The unstable hydrogenation products are derivatized with (‐)‐menthyl chloroformate. An improved HPLC procedure for the analysis of the products has been developed. By using optically active chelate phosphanes as cocatalysts together with [Rh(cod)Cl]2, a diastereomeric excess of up to 24% of the natural isomer 2a with (6S,S)‐configuration is attained in the heterogeneous hydrogenation of folic acid.
Kleine Ringe, 74. Hexa‐tert‐butyl‐3,3′‐bicyclopropenyl
Authors: Maier Günther , Schick Andreas , Bauer Ines , Boese Roland , Nussbaumer Michael 
Published: July 2007

Small Rings, 74[1]. ‐ Hexa‐tert‐butyl‐3,3′‐bicyclopropenylTitle compound 3 can be prepared by reductive coupling of tri‐tert‐butylcyclopropenylium tetrafluoroborate (4a) with lithium. Upon treatment with AgBF4 3 does not undergo valence isomerization to the Dewar form of hexa‐tert‐butylbenzene (2) but is reoxidized under backformation of substrate 4a. The photochemical behavior of 6 is also unusual: Irradiation at room temperature results in gas evolution. However, instead of 7, the s̀‐diketone 5 is isolated. Monoketone 7 is only formed if 6 is irradiated in an organic matrix at ‐196°C.
Reductive transformations, 20. Synthesis of n‐alkyl‐substituted perylenes and terrylenes via alkali‐metal induced cyclization of oligonaphthylenes
Authors: Anton Ute , Göltner Christine , Müllen Klaus 
Published: July 2007

AbstractThe synthesis of two novel n‐alkyl‐ or aryl‐substituted perylenes and of an n‐alkylated terrylene is possible by an alkalimetal induced cyclization of the corresponding bi‐ or trinaphthyls. Differences in reactivity of the naphthylenes in the ringclosure reaction are caused by the different substitution pattern. UV and fluorescence spectra as well as the stability of the resulting rylenes[2] are discussed as a function of substitution.
Metallkomplexe in Biologie und Medizin, IV. Darstellung und Kristallstruktur von Bis(2–aminoethanthiolato)bismut(III)‐nitrat–Monohydrat
Authors: Herrmann Wolfgang A. , Kiprof Paul , Scherer Wolfgang , Pajdla Liba 
Published: July 2007

Metal Complexes in Biology and Medicine, IV[1]. – Synthesis and Structure of Bis(2–aminoethanethiolato)bismuth(III) Nitrate MonohydrateReaction of bismuth(III) nitrate with 2–aminoethanethiol results in the formation of bis(2–aminoethanethiolato)bismuth(III) nitrate monohydrate (1), the solid–state structure of which has been established by single–crystal X–ray diffraction. The bidentate chelating ligand leads to the formation of five–membered rings. Due to interaction of neighbouring units via Bi–S bonds, a polymeric three–dimensional structure results in the crystal lattice. The bismuth atom has an eightfold coordination with two coordination sites being provided by sulphur atoms of adjacent molecules.
Highly Functionalized Vinylcyclopropane Derivatives by Regioselective and Stereoselective Reactions of Fischer Carbene Complexes with 1,4–Disubstituted Electron–Deficient 1,3–Dienes
Authors: Buchert Matthias , Reißig Hans–Ulrich 
Published: July 2007

AbstractThe thermal reaction of Fischer carbene complex 1 with electron–deficient 1,3–dienes such as methyl (E,E)‐2,4–hexadienoate (2) provided functionalized vinylcyclopropanes like 3 in good yields. Similar results were obtained by employing related unsaturated esters 4, 17, and 21 or nitrile 6. The periselectivity as well as regioselectivity of these carbene–transfer reactions are generally very high, and the diastereomer with the methoxy group cis‐positioned with respect to the olefinic moiety is largely favoured (>85:15). A mechanistic rationale of these observations is given. Double adducts were only formed as minor sideproducts in these reactions, but by employing amide 13 as electron–deficient diene they were very easily formed with 1. The [2 + 1] cycloaddition could also be extended to methylcarbene complex 24 and diene 2, but the corresponding vinylcyclopropane 25a was so far only obtained in low yield.
Chiral Organometallic Reagents, IX. On the Origins of the Diastereoselectivity in the Bromine/Lithium Exchange of 3–Alkoxy–1,1–dibromoalkanes
Authors: Hoffmann Reinhard W. , Brumm Karen , Bewersdorf Martin , Mikolaiski Wolfgang , Kusche Andreas 
Published: July 2007

AbstractThe 3–alkoxy–1,1–dibromopentanes 5 are compounds, which according to MM2 calculations populate one conformation to >80% at −110°C. On reaction with n‐butyllithium the bromine atom which resides in the extended position is exchanged with selectivities around 80:20, irrespective of the nature of the oxy residue at C–3. The role of this substituent is solely to bias the conformational equilibria in favor of the conformer 17. Coordination of the butyllithium to the oxygen functionality plays an important role only in the carbamoyl derivative 5f, for which the sense of the asymmetric induction is reversed.
Kristallstruktur und Gasphasenuntersuchungen von lithiiertem Acetessigsäure‐tert‐butylester
Authors: Waldmüller Delia , Mayer Bernhard , Braun Manfred , Hanuschik Andreas , Krüger Carl , Guenot Pierre 
Published: July 2007

Crystal Structure and Gas–Phase Investigations of Lithiated tert‐Butyl AcetoacetateThe lithium enolate 2, generated either by deprotonation of tert‐butyl acetoacetate (1) or by pyrolysis of lithiated tert‐butyl acetate (3) is crystallized from toluene. The X–ray diffraction analysis of unsolvatized 2 reveals a hexameric structure. Thereby, the central skeleton is formed by two Li–O six–membered rings, and the carbonyl group of the ester moiety serves to complete the fourfold coordination of the lithium atom. The thermal stability of 2 enables the very first mass spectrometric and photoelectron spectroscopic investigation of a lithium enolate. The lithium compound 2 forms aggregates even in the gas phase. The first vertical ionization energy of 2 is found to be significantly lower than those observed in the photoelectron spectra of both the enol ether 5 and the ester 1.
Preparative, X‐ray, and NMR Studies of the Interaction of Beryllium with Salicylic and o‐Cresotic Acid: Crystal Structures of (NH4)2[Be(C6H4OCO2)2] · 2.25 H2O and Na3[Be(C7H6OCO2)(OH)(CO3)Be(C7H6OCO2)] · 8 H2O
Authors: Schmidbaur Hubert , Kumberger Otto 
Published: July 2007

AbstractThe existence of well‐defined crystalline beryllium salicylate(2 – ) and bis[salicylato(2 – )]beryllate complexes as well as of their o‐cresotate analogs is established. The structure of (NH4)2[Be(C6H4OCO2)2] · 2.25 H2O has been determined by an X‐ray structure analysis. It contains a beryllate anion of the composition [Be(C6H4OCO2)2]2– with two salicylate(2 – ) ligands acting as chelate ligands. The considerable 9Be NMR chemical shifts observed for aqueous solutions of the pure compounds indicate in all cases the persistence of the complexation of the metal ion by the catecholate ligands. 9Be NMR studies of aqueous solutions containing BeSO4 · 4 H2O and sodium salicylate(1 – ) or sodium o‐cresotate(1 – ) in the molar ratios 1:1 and 1:2 show that a variety of beryllium/salicylate(2 – ) and beryllium/o‐cresotate(2 – ) species are present in solution, the most prominent being Be(C6H4OCO2)‐(H2O)2 and [Be(C6H4OCO2)2]2– (and their o‐cresotate analogs). From such solutions in contact with air, a novel dinuclear beryllium hydroxido/o‐cresotato(2 – )/carbonato complex of the stoichiometry Na3[Be2(OH)(CO3)(C7H6OCO2)2] · 8 H2O is isolated. According to an X‐ray analysis the compound contains a cyclic beryllate anion with two Be(C7H6OCO2) chelate units linked by bridging hydroxide and carbonate anions. In the light of the ubiquitous availability of phenolic and carboxylic groups in many biomolecules, the finding of strong bonding of Be2+ to these functions in aqueous solution is very important.