bluuebunny/crossref_metadata_2025_split huggingface dataset:
Quantenmechanische Berechnungen zu pseudo-einstufigen (C-C)-Spaltungen bei Radikalkationen von Carbonsäuren / Quantum Mechanical Calculations on Pseudo-One-Step Cleavages of Carbonic Acid Cation Radicals
Authors: Frenking Gemot , Schmidt Jochen , Schwarz Helmut 
Published: February 2015

Abstract
Extensive quantum mechanical calculations on the unrestricted MINDO/3 level reveal that for some ionised carbonic acids the energetically most feasible pathway for uni-molecular C-C cleavage cannot be described as being a one-step process. In complete agreement with experimental results the computational data are consistent with an inter-pretation of the reaction as being a two-step process, in which the reaction commences with a hydrogen migration from a CH-bond onto the ionised C = 0 group. The dissociation is completed with a radical induced C-C cleavage thus generating quite stable protonated unsaturated carbonic acids. Whereas the MINDO/3 results clearly show that the two-step process is energetically favoured over the direct C-C cleavage, this computational method fails badly in explaining the experimentally established fact that in the two-step sequence the hydrogen migration is the rate-determining step. This failure is due to the MINDO/3 inherent weakness of overestimating the stability of cyclic ions, e.g. cyclic transition states as they are formed in the course of the hydrogen migration step. Single point ab initio calculations carried out on the 4-31G level substantiate this interpretation in that the transition state for the hydrogen migration is calculated to lie substantially higher than that for the actual C-C dissociation step, but is still much lower than that calculated for a direct simple bond cleavage process of the respective cation radical.
Vom "criss-cross"-Schema abweichende Cycloadditionsreaktionen an das Azin-System [1] Zum Cycloadditionsverhalten von Hexafluoracetonazin gegenüber N.N-Dialkyl-cyanamiden [2] / Cycloaddition Reactions of Azines Violating the "criss-cross" Cycloaddition Scheme [1] Cycloaddition Behaviour of Hexafluoroacetone Azine towards N,N-Dialkyl-cyanamides [2]
Authors: Burger Klaus , Hein Friedrich , Firl Joachim 
Published: February 2015

Abstract
Depending upon the molar ratio of the educts and the reaction conditions used, hexa-fluoroacetone azine (1) reacts with N,N-dialkyl-cyanamides (2) to give 3,4,6-triazaocta-2,4,6-trienes (6) and/or 4,4-bis(trifluoromethyl)-1,4-dihydro-1,3,5-triazines (7). Cyclo-addition reactions of 6 with tert-butyl isocyanide and 1-diethylamino(propine) are de-scribed. IR, 1H, 19F, and 13C NMR data of the new compounds are discussed.
Die Photoaddition von Bromtrichlormethan an Allyl-Systeme / Photoaddition of Bromotrichloromethane to Allylic S ystems
Authors: Seidel Peter , Ugi Ivar 
Published: February 2015

Abstract
The preparation of various 1-substituted 4,4,4-Trichloro-2-bromo-butanes by photo-addition of bromotrichloromethane to allylic systems is described. Generally a more uniform product and a higher yield are obtained by this photoaddition than by the corresponding chemically initiated radical chain reaction.
The Chemical Evolution of a Nitrogenase Model, 20 Alkyl Molybdates(VI) and the Mechanism of Hydrocarbon Production by Nitrogenase [1]
Authors: Schrauzer G. N. , Hughes Laura A. , Strampach Norman 
Published: February 2015

Abstract
Colorless alkylmolybdates(VI) of composition R-MoO3-are generated in aqueous solutions by the alkaline hydrolysis of complexes R-Mo(Bpy)(0)2Br(Bpy = 2,2′-bipyridyl, R = CH3 and higher alkyl). At room temperature in alkaline aqueous solution, the new organometallic derivatives of oxomolybdate(VI) are remarkably resistant against Mo-C bond hydrolysis. Decomposition occurs more rapidly on heating, affording unrearranged alkanes according to the eq.: R-MoO3
- + OH-→RH + Mo04=.
In acidic solutions, the methylmolybdate(VI) species decomposes with the formation of a mixture of methane and ethane while higher alkylmolybdates carrying hydrogen in the β-position relative to molybdenum undergo Mo-C bond heterolysis by way of β-elimina-tion: R-CH2CH2-MoO3 → Mo+4 (aq) + H+ + R-CH = CH2.
The Mo-C bond of alkylmolybdates is resistant to oxidants but is very sensitive to cleavage under reducing conditions. Reductive Mo-C bond cleavage occurs particularly rapidly in the presence of thiols and reduced ferredoxin model compounds. The latter reactions simulate the terminal steps of hydrocarbon producing reactions of nitrogenase with alternate substrates such as CN-, R-CN or R-NC, confirming previous mechanistic conclusions concerning the mechanism of nitrogenase action.
Darstellung und Kristalldaten der isotypen Aluminum (Gallium)-Indium-Sulfide Al2In4S9 und Ga2ln4S9 / Preparation and Crystal Data of the Isotypic Aluminium (Gallium) Indium Sulphides Al2In4S9 and Ga2ln4S9
Authors: Schulte-Kellinghaus M. , Krämer V. 
Published: February 2015

Abstract
The title compounds were prepared by chemical vapour transport. They crystallize in the space group P3̅m 1 with the lattice parameters a = 7.532(3) (7.589(5)) and c = 36.54(2) (36.70(5))!. X-ray powder diffraction data are listed and the T,x phase diagram of the system AlInS3-In2S3 is shown.
Heterogeneous Catalysis, VI Direct Reduction of Alcohols to Hydro- carbons [1]
Authors: Maier Wilhelm F. , Thies Irina , Ragué Schleyer Paul von 
Published: February 2015

Abstract
Secondary and tertiary alcohols are converted cleanly to the parent hydrocarbons in the gas phase with H2 in the presence of a Ni/Al2O3 catalyst at 190 °C. Primary alcohols are de-hydroxymethylated; e.g., 1-hydroxymethylada-mantane (4) gives adamantane (1). Alumina alone, in the absence of Ni, results in the formation of homoadamantane (5) from 4.
Compounds of Complex Halo and Pseudohalo Acids of the Group IIB Metals, Part V [1] Preparative and Spectroscopic Studies of the [Hg2I5]-, [Hg2I6]2- and [Hg3I8]2- Ions
Authors: Perlepes S. P. , Zafiropoulos Th. F. , Anagnostopoulos A. K. , Galinos A. G. 
Published: February 2015

The preparations of new compounds, containing the complex anions [Hg2l5]-, [Hg2l6]2- and [Hg3I8]2-, are reported.
Distorted iodine-bridged configurations are proposed for the complexes in the solid state, utilising analyses, X-ray powder patterns, molar conductance measurements and spectral (IR, UV) data
Synthese eines Doppel-Carbodiphosphorans und seiner Vorstufen / Synthesis of a Double-Carbodiphosphorane and its Precursors
Authors: Schmidbaur Hubert , Costa Thomas 
Published: February 2015

Abstract
The reaction of 1,4-dibromobutane with bis(diphenylphospliino)methane (1) yields two products, one of which is identified as butane-1,4-bis[diphenyl(diphenylphosphinomethyl)-phosphonium bromide] (3 a). Transylidation of this bis-phosphonium salt using two equiv-alents of (CH3)3P = CH2 affords the bis-ylide [CH2CH2P(C6H5)2 = CH-P(C6H5)2]2 (4) in high yields. This conversion can be reversed on treatment of 4 with etheral HCl (to give 3b). Methylation of 4 with CH3I occurs at phosphorus, however, and produces the bis-semiylide salt (5), [CH2CH2P(C6H5)2CHP(C6H5)2CH3]2
2⊕ 2I⊖. Transylidation of 5 (again with (CH3)3P = CH2) leads to the bis-carbodiphosphorane (6), [CH2CH2P(C6H5)2 = C = P(C6H5)2CH3]2. All compounds were characterized by elemental and detailed NMR analyses. The second product of the above quaternisation reaction is a cyclic bis-phosphonium salt (2) with a seven-membered ring structure.
η2-Koordination eines Hydroxylamid(2-)Anions: Die Kristallstruktur von [Mo(NO)(terpy)(CN)(HNO)] 2H2O / η2-Coordination of a Hydroxylamido(2-) Anion: The Crystal Structure of [Mo(NO)(terpy)(CN)(HNO)]2H2O
Authors: Wieghardt Karl , Holzbach Wolfgang , Weiss Johannes 
Published: February 2015

Abstract
The red, diamagnetic complex [Mo(NO)(terpy)(CN)(HNO)] • 2H2O crystallizes in the triclinic space group P1̅(C1
i-No2) with cell constants a = 867.1(3), b = 1008.4(4), c = 1095.6(3) pm, a = 73.64(3)°, β = 83.54(3)°, γ = 83.16(3)°, and Z = 2. The final R value of the single crystal X-ray analysis is 0.063 for 1922 unique reflections. The structure consists of neutral complexes of [Mo(NO)(terpy)(CN)(HNO)]. The geometry about the molybdenum is a distorted pentagonal bipyramid with a linear NO and CN group in the axial positions, a triclentate terpyridine ligand and an O,N-coordinated HNO2- ligand in equatorial positions.
Über Oxostannate(II), IV [1] Zur Kenntnis von Rb2SnO2 und K2SnO2 [2] / On Oxostannates(II), IV Rb2SnO2 and K2SnO2
Authors: Braun Rolf M. , Hoppe Rudolf 
Published: February 2015

Abstract
The new compound Rb2SnO2 was obtained as a light yellow powder by heating mixtures of the binary oxides (RbO0.48 + SnO, Rb: Sn = 2:1) under argon (sealed Ag cylinders, 600 °C, 3d). Subsequent annealing (550 °C, 8d and 500 °C, 17 d) led to light yellow transparent single crystals. Rb2SnO2 is extremely sensitive to moisture and decomposes into black products. It crystallizes orthorhombicly in the space group P212121-D4
2, with a = 5.761, b = 7.493, c= 11.167 Å, Z = 4, drö = 4.43 and dpyk = 4.46 gcm-3 , R= 11.8 and Rw = 12.0%. Effective Coordination Numbers, ECoN, these via Mean Fictive Ionic Radii, MEFIR, and the Madelung Part of Lattice Energy, MAPLE, have been calculated. Isotypic K2SnO2 was obtained similarly as a brown powder, a = 5.579, b = 7.246, c = 16.744 Å.
Die Kristallstruktur des 2:1-Adduktes von Antimontribromid mit Biphenyl, 2SbBr3 · C12H10 / The Crystal Structure of the 2 : 1 Adduct of Antimony Tribromide with Biphenyl, 2SbBr3-C12H10
Authors: Lipka Annegret , Mootz Dietrich 
Published: February 2015

Abstract
The crystal structure of 2 SbBr3 · biphenyl consists of pyramidally shaped SbBr3 molecules and planar biphenyl molecules which form a centrosymmetric complex through bonding of the Sb atoms to the phenyl rings. The distance of the Sb atoms to the phenyl ring planes is 323 pm. Taking into account intramolecular bonds Sb-Br at an average of 250.9 pm, an intermolecular Sb···Br contact at 369.5 pm and the π-donor-acceptor inter-action the Sb coordination is distorted ψ-octahedral. The structure is discussed with regard to related compounds.
cis- und trans-Halogeno(2-N.N-dimethylaminophenyl)bis- (triphenylphosphan)platin(II). Synthesen, Struktur und Isomerisierungen / eis- and trans-Halogeno(2-N,N-dimethylaminophenyl)bis(triphenylphosphane)platinum(II). Syntheses, Structure and Isomerizations
Authors: Wiege Manfred , Brune Hans Albert , Klein Heinz-Peter , Thewalt Ulf 
Published: February 2015

Abstract
cis-Chloro(2-N,N-dimethylaminophenyl)bis(triphenylphosphane)platinum(II) and cis-Bromo(2-N,N-dimethylaminophenyl)bis(triphenylphosphane)platinum(II) have been syn-thesized and converted to the corresponding trans-isomers. The crystal and molecular structure of imns-chloro(2-N,N-dimethylaminophenyl)bis(triphenylphosphane)platinum-(II) has been determined by X-ray diffraction. The molecular structure is discussed with respect to possible coordination of the ortho-located N,N-dimethylamino substituent with the central atom.
Protonkatalysierte Wasser-Abspaltung aus 1-Dekalon und 8α-Methyl-1-dekalon in the Gasphase. Verlust der stereochemischen Integrität der cis/traras-Ringverknüpfung bei [MH]+ -Ionen / Proton Catalyzed Water Elimination from 1-Decalon and 8α-Methyl-1-Decalon in the Gas Phase. Loss of the Stereochemical Integrity of the cis/trans Ring Juncture for [MH]+ Ions
Authors: Wrolfschütz Roland , Halim Hermann , Schwarz Helmut 
Published: February 2015

Abstract
Water loss from protonated gaseous 1-decalon and 8α-methyl-1-decalon under the condition of chemical ionisation mass spectrometry proceeds via at least three distinct pathways, all of which commences with a [1.2]-hydrogen or [1.2]-methyl migration, thus giving rise to the formation of the central intermediate 10. H2O loss from 10 proceeds either directly, involving a hydrogen from the position (C-4a) (Scheme 3; pathway 10 →15 →16), or from the rearranged ions 17 and/or 20. The fact that eis-and trans-8α-methyl-1-decalones and their deuterated isotopomers behave essentially identical is explained by loss of the stereochemical integrity of the ring conjunction. The mechanistic features of this unusual process (Scheme 2) have been explored by semi-empirical MINDO/3 calculations for the model system 23 (Scheme 4). The calculations reveal that there are two competing pathways for CH3 migration, one involving a sequence of [1.2]-shifts (23 →24 →25 →26→27), the other -being energetically less favoured -corresponds to a direct [1.3]-methyl migration (Scheme 6; 23 →33 →27), in which the methyl group migrates with retention of configuration. This process is symmetry forbidden. For the corresponding symmetry allowed [1.3]-methyl migration with inversion of configuration of the migrating group no pathway could be detected computationally. Both the experi-mental and theoretical investigations allow one to draw a detailed picture of H2O loss from protonated cyclic ketones in the gas phase. -The syntheses of the labelled substrates are described in detail.
Novel Sublimable Dithioates-Pyridinium and Picolinium Dithiocarboxylates
Authors: Kato Shinzi , Chiba Shinya , Mizuta Masateru , Ishida Masaru 
Published: February 2015

Abstract
Pyridinium Dithiocarboxylates, Picolinium Dithiocarboxylates Pyridinium and picolinium dithiocarboxylates, which can be readily obtained from the corresponding dithio acids and pyridine or picoline, were found to sublimate easily under the conditions of ca. 3 torr at room temperature.
An Improved of α-(Thioaeylthio)methylphenyl-Ketones using Caesium Dithioates and a Convenient Synthesis of 2,4-Disubstituted 1,3-Thiazoles via the Ketones
Authors: Kato Shinzi , Yamamoto Sakae , Ando Kohji , Itoh Katsumi , Mizuta Masateru , Ishida Masaru 
Published: February 2015

Abstract
α-(Thiocylthio)methylphenylketones, 2,4-Disubstituted 1,3-Thiazoles, Caesium Dithioates α-(Thioacylthio)methylphenylketones were found to be obtained in almost quantitative yields from caesium dithioates and a-phenacyl bromide. Refluxing of these ketones with ammonium acetate in gracial acetic acid affords the corresponding 2,4-disubstituted 1,3-thiazoles. While, the similar reaction of α-(thioisobutyrylthio)methylphenylketone gives the dithiafulvene (4).
Zur Chemie des Ingenols, II [1] Ester des Ingenols und des ⊿7.8 -Isoingenols / On the Chemistry of Ingenol, II [1] Esters of Ingenol and ⊿7.8 -Isoingenol
Authors: Sorg Bernd , Hecker Erich 
Published: February 2015

Abstract
Preparation and purification of 3-acylates of ingenol (1a) structurally related to naturally occuring, irritant and cocarcinogenic principles are described. It is shown that 3-acylates partly rearrange to corresponding 5-acylates when they are chromatographecl. From the 3-acylates or from ingenol (1a) a mixed and a symmetric ingenol-3,20-diacylate is synthesized respectively. Ingenol-5,20-acetonide (2a) is rearranged to its ⊿7.8-isomer 3b. Starting with 3b ⊿7.8-isoingenol (3a) and the 3-tetradecanoate of ⊿7.8-isoingenol (3d) are prepared. Most of the ingenol derivatives prepared are tested for their irritant activity on the mouse ear.
Zur Reaktion von Fluorcyan: Darstellung von N-Trifluormethyl - S-trifluormethyl-schwefelfluoridimid, CF3-NSF(CF3), und -schwefelchloridimid, CF3-NSCl(CF3) / Reaction of Cyanogen Fluoride : Preparation of N-Trifluoromethyl-S-trifluoromethyl- imidosulfurfluoride, CF3-NSF(CF3) and -imidosulfurchloride, CF3-NSCl(CF3)
Authors: Leidinger Walter , Sundermeyer Wolfgang 
Published: February 2015

Abstract
N-Trifluoromethyl-S-trifluoromethylimidosulfurfluoride and chloride CF3NSX(CF3) (X = F, Cl) were obtained from cyanogen fluoride and trifluoromethylsulfurtrifluoride and subsequent halogen exchange, respectively.
Organoaluminum Radical Complexes from the Single Electron Transfer Reaction of Diisobutylaluminum Hydride with N-Heterocycles
Authors: Kaim Wolfgang 
Published: February 2015

Abstract
Diisobutylaluminum hydride iBu2AlH reacts with N-heterocycles L (L = pyrazine, 2,2'-bipyridine, 4,4'-bipyridine) via single electron transfer to yield 1:1 radical complexes [L(AliBU2)·].
Kristallstrukturen und Schwingungsspektren des Heteropolysulfats [N(CH3)4]6S2V2W16O62 und des Vanadatowolframats Na[N(CH3)4]2VW5O19 · H2O / Crystal Structures and Vibrational Spectra of the Heteropolysulfate [N(CH3)4]6S2V2W16O62 and the Vanadatotungstate Na[N(CH3)4]2VW5O19 · H2O
Authors: Botar Alexandru , Fuchs Joachim 
Published: February 2015

Abstract
X-ray analysis of [N(CH3)4]6S2V2W16O62 furnishes evidence for the existence of a discrete heteropolysulfate ion. The compound crystallizes monoclinic, space group P21/C with lattice parameters a = 13.361(5) Å, b = 25.378(1) Å, c = 28.847(5) and β = 91.37(3)°. Its anion has the configuration (Dawson structure) first observed in K6P2W18O62 · 14 H2O. [N(CH3)4]2NaVW5O19 · H2O, formed as a side product in the preparation of the hetero-polysulfate, crystallizes in the orthorhombic space group Pmnm with lattice constants a = 12.810(3) Å, b = 10.842 Å and c = 9.703(4) Å. Its anion belongs to the known hexa-metallate type M6O19
z− . The sodium ion is pentacoordinate (trigonal bipyramidal). The water of crystallization belonging to its coordination sphere exhibits the extremely short Na-O distance of 2.19 Å. The Na+ ··· H2O grouping appears to cause an IR as well as Raman active vibration band at 1290 cm-1 .
Darstellung von Diphenylbismutcarboxylaten / Preparation of Diphenylbismuth Carboxylates
Authors: Huber Friedo , Bock Sigrid 
Published: February 2015

Abstract
Diphenylbismuth carboxylates Ph2BiX (X = OAc = CH3COO, C2H5COO, C3H7COO, Me2CHCOO, Me3CCOO, CH3COCH2CH2COO, PhCOO; Me = CH3; Ph = C6H5) have been prepared from Ph2BiCl and NaX or from Ph2BiOC2H5 and HX in anhydrous ethanol. PhoBiOAc and a compound of approximate composition PhBi(OAc)2 have been obtained in small yields from acidolysis of Ph3Bi with HOAc (molar ratio 1:1 and 1:3, resp.) in acetone. A polymeric structure with bridging bidentate carboxylate groups is proposed for Ph2BiX compounds.
Darstellung und Kristallstruktur von KNaO und RbNaO / Preparation and Crystal Structure of KNaO and RbNaO
Authors: Sabrowsky Horst , Schröer Ulrich 
Published: February 2015

Abstract
Potassium Sodium Oxide, Rubidium Sodium Oxide The compounds KNaO and RbNaO have been prepared and their structures determined by powder and single crystal data. Both compounds show the anti-PbFCl crystal structure type with two molecular units. KNaO: a = 400.2(1) pm, c = 621.4(2) pm, c/a= 1.553; RbNaO: a = 409.3(9) pm, c = 653.1(9) pm, c/a = 1.595.
Synthesen von Adenin und Guanin aus Ammoniumcyanid und Cyansäure in Zeolith X / Synthesis of Adenine and Guanine from Ammonium Cyanide and Cyanic Acid in Zeolithe X
Authors: Seel Fritz , Blon Martin von , Dessauer Andreas 
Published: February 2015

Abstract
Adenine (1) is formed in substantial amounts (about 1% yield) by heating ammonium cyanide absorbed in zeolithe X for several days at 120 °C. If both, ammonium cyanide and cyanic acid have been absorbed, 1 and guanine (2) are synthesized under the same conditions. These experiments provide the first demonstration of the possibility of a spontaneous synthesis of these essential constituents of nucleic acids and of important coenzymes in a silicate.
The Crystal Structure of Carbonyl Gold(I) Chloride, (OC)AuCl
Authors: Jones Peter G. 
Published: February 2015

Abstract
The crystal structure of (OC)AuCl has been determined and refined to R 0.037 (space group Cmcm, a = 407.1(1), b = 1042.2(4), c = 532.1(3) pm, Z =4). The structure consists of discrete, exactly linear molecules; all atoms lie on the special positions 0, y, 1/4. The bond lengths involving the light atoms are affected by libration. The shortest Au ··· Au contacts between molecules are 338 pm.
On the Structure of the Claasz's Sulfurylindoxyl
Authors: Somogyi László 
Published: February 2015

Abstract
On chemical, IR and 1H NMR spectroscopic evidences the structure of the so-called sulfurylindoxyl was found to be 2-aminophenyl methyl sulfone (4) and not the benzo-thiazoline-1,1-dioxide (7) claimed by Claasz [1]. Contrary to data in the literature [2] the title compound gives only one sort of monoacetyl derivatives: 2-acetamidophenyl methyl sulfone (10). An unambiguous synthesis of 3-acetylbenzothiazoline-1,1-dioxide (8) is presented.
Übergangsmetall-substituierte Phosphane, Arsane und Stibane, XXX Redoxreaktionen zwischen Triorganodibromphosphoranen oder -arsoranen und Ubergangsmetall -Anionen / Transition-Metal Substituted Phosphanes, Arsanes and Stibanes, XXX Redox Reactions between Triorganodibromophosphoranes or -arsoranes and Transition Metal Anions
Authors: Meyer Angelika , Hartl Anna , Malisch Wolfgang 
Published: February 2015

Abstract
The reaction of the sodium carbonyl metalate Na[W(CO)3Cp] with the phosphorane (Me3SiCH2)3PBr2 results in the formation of (Me3SiCH2)3PandCp(CO)3WBr or [Cp(CO)3W]2, respectively, depending on the solvent used. The redox reactions between Na[Mo(CO)3Cp] and the arsenic analogue (RCH2)3AsBr2 (R = Ph, Me3Si) yield the products Cp(CO)sMoBr and (RCH2)3As. A mechanism involving radicals is discussed. At elevated temperatures the products react further to give the square pyramidal complexes cis-Cp(CO)2[As(CH2R)3]MBr (1, 2a, b) with loss of CO. In an analogous manner Cp(CO)3MBr (M = Mo, W) and (RCH2)3E (E = As, Sb) afford compounds cis-Cp(CO)2[E(CH2R)3]MBr (2c, 3). The dynamic behaviour of the chiral complexes 1, 2a, b, was investigated by 1H NMR spectroscopy.
2.5-Dihydro-und Tetrahydro-2.2-dimethyl-3-thiophenaldehyd / 2,5-Dihydro-and Tetrahydro-2,2-dimethjd-3-thiophenealdehyde
Authors: Sucrow Wolfgang , Müller Hans-Walter 
Published: February 2015

Abstract
The preparation of the title aldehydes 1 and 6 a, the corresponding alcohols 2 a and 6 b and some other derivatives is described.
Preparation and Structures of Ternary Copper(II) Complexes of ADP and ATP Models for Enzyme-Metal Ion-Nucleoside Polyphosphate Complexes
Authors: Sheldrick William S. 
Published: February 2015

Abstract
The stable ternary copper(II) complexes of ATP and ADP, [Cu(H2ATP)(phen)]2 · 7 H2O (2) and [Cu4(HADP)2(bipy)4(H2O)2(NO3)2] · 2 NO3 (3), have been isolated from aqueous solution at respective pH values of 2.8 and 4.0. Their structures have been established by single crystal X-ray diffraction. Tridentate coordination of each of the Cu atoms by ono α-, one β- and one γ-phosphate O atom of one ATP molecule is observed in 2. The binding Oα atoms occupy axial positions in a distorted octahedral geometry at Cu and the Cu- Oα interactions are weak. The other axial position is occupied by a γ-phosphate O atom of the second ATP molecule, leading to a dimeric structure. The basic structure of 3 is similar with, in this case, bidentate coordination of each of the central Cu atoms by one α- and one β-phosphate O atom of ono ADP molecule. In this case, however, the third terminal β-phosphate O atoms each bind a further Cu atom. All four Cu atoms in 3 display square pyramidal coordination. The structures of 2 and 3 are stabilised by intramolecular stacking of adenine and phenanthroline/bipyridyl systems. The significance of these structures as models for enzyme-metal ion-nucleoside polyphosphate complexes is discussed.