| | 62 | Author
| Z. Naturforsch | Requires cookie* | | | Title
| Experimental and Computational Studies on Aminoguanidine Free Base, Monocation and Dication. Part III: Proton Affinities of Guanidine, Aminoguanidine and Glyoxal Bis(amidinohydrazone)  | | | | Abstract
| The structures of glyoxal bis(amidinohydrazone) (GBG) free base and glyoxal bis(amidi-nohydrazonium) monocation and dication were calculated quantum chemically by using the density functional hybrid method B3-LYP with the standard basis set 6 -3 1 G (d). Proton affinities calculated from these data are 246.4 kcal/mol for the free base and 176.0 kcal/mol for the monocation. The proton affinities of guanidine free base (246.2 kcal/mol), am inogua nidine free base (242.9 kcal/mol), aminoguanidinium monocation (88.6 kcal/mol) were calcu lated for reference. The B3-LYP functional overestimates the proton affinities for all the species studied. For example, for guanidine the proton affinity at the M P2/6-31G (d) level is 238.3 kcal/mol, the experimental reference value being 233 kcal/mol. However, from the B3-LYP values it can be concluded that in the gas phase all the three bases are nearly equally basic. On the other hand, it is known that in aqueous solution guanidine is a much stronger base than aminoguanidine and glyoxal bis(amidinohydrazone). The results are discussed from the point of view of molecular size, shape and symmetry, and hydrogen bonding in solution. | | | |
Reference
| Z. Naturforsch. 53b, 386—392 (1998); received November 21 1997 | | | |
Published
| 1998 | | | |
Keywords
| Proton Affinity, Gas Phase Basicity, Acid Dissociation Constant | | | |
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| default:Reihe_B/53/ZNB-1998-53b-0386.pdf | | | | Identifier
| ZNB-1998-53b-0386 | | | | Volume
| 53 | |
| 64 | Author
| J. Feller3, H. Oppermann3, R. Kucharkowskib, S. Däbritzc | Requires cookie* | | | Title
| Phasenbeziehungen und Chemischer Transport der Verbindungen im ternären System Re/Mo/O Phase Relations and Chemical Transport of the Compounds in the Ternary System Re/Mo/O | | | | Abstract
| In the ternary system Re/Mo/O four series of mixed oxides have been prepared by heating of powder samples and by transport reactions. The series are derived from the oxides R e 0 2, M o 0 2, 7 -Mo4O u und //-Mo40 |i and have compositions R e1_ vM ov0 2 (0 < x < 0.37), M o,_> .Re>0 2 (0 < v < 0 .4 2),7 -M o 4_-| Re-| 0 11 (0 < Zj < l),a n d /7-Mo4_.2Re-^Ö |, (0 < z 2 < 1). Contributions to the understanding of the transport mechanism were obtained from thermodynamic calculations. The composition of the mixed crystals obtained have been determined by EPM A and ICP-AES. | | | |
Reference
| Z. Naturforsch. 53b, 397—104 (1998); eingegangen am 21. Januar 1998 | | | |
Published
| 1998 | | | |
Keywords
| Rhenium Molybdenum Mixed Oxides, Chemical Transport Reaction, Phase Diagram | | | |
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| default:Reihe_B/53/ZNB-1998-53b-0397.pdf | | | | Identifier
| ZNB-1998-53b-0397 | | | | Volume
| 53 | |
| 65 | Author
| Matthias Asbrand, Brigitte Eisenmann, Holger Engelhardt, Ute Rößler | Requires cookie* | | | Title
| Dimere und polymere Pnictidostannat(IV)-Anionen -Darstellung und Kristallstrukturen von Na2K3[SnP3], Na2Cs3 [SnP3] und Na2K3[SnBi3] Dimeric and Polymerie Pnictidostannate(IV) Anions -Preparation and Crystal Structures of Na2K3[SnP3], Na2Cs3[SnP3] and Na2K3[SnBi3] | | | | Abstract
| Disodium Tripotassium Triphosphidostannate(IV), Disodium Tricesium Triphosphidostanna-te(IV), Disodium Tripotassium Tribismutidostannate(IV), Dimeric Tetrahedral Anions, Zweier Single Chains The metallic lustrous compounds Na2K3[SnP3], Na2Cs3[SnP3], and Na2K3[SnBi3] were pre pared from melts of mixtures of the elements. The isotypic compounds Na2K3[SnP3] and Na7Cs3[SnP3] crystallize in the orthorhombic system, space group Cmca (No 64), Z = 8, with lattice constants a = 1996.1 (4)/2047.9(4) pm, b = 669.5(1)/686.5(2) pm, c = 1494.5(2)/1617.8(3) pm. The structure is characterized by dimeric units [Sn2P6] l0_ of edge-sharing [SnP4] tetrahe dra, which are coordinated by the alkali cations. Na2K3[SnBi3] crystallizes in the orthorhombic system, space group Ibca (No 73), Z = 8, with lattice constants a = 718.2(1) pm , b -1692.6(2) pm, c = 2159.5(2) pm. In the anionic partial structure [SnBi4] tetrahedra are connected via common corners to infinite ^ [SnBi3]5_ Zweier single chains. The sodium and potassium cat ions separate the chains from each other. Neglecting the distortions caused by covalent bonding and different radii both structure types can be classified as superstructure defect variants of the Li3Bi structure. Different orderings in the occupation of the tetrahedral voids lead to the variants in the anionic assemblies. | | | |
Reference
| Z. Naturforsch. 53b, 405—410 (1998); eingegangen am 26. Januar 1998 | | | |
Published
| 1998 | | | |
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| default:Reihe_B/53/ZNB-1998-53b-0405.pdf | | | | Identifier
| ZNB-1998-53b-0405 | | | | Volume
| 53 | |
| 66 | Author
| Bernd Wrackmeyer, Ēriks Kupče+ | Requires cookie* | | | Title
| Some Applications of Ultrahigh Resolution 15N NMR Spectroscopy | | | | Abstract
| NMR Data, Ultrahigh Resolution Ultrahigh resolution l5N NM R spectra were measured for two nitroalkanes (M eNÜ2 la, fBuN02 lc), two isocyanates (;BuNCO 2c, Me^SiNCO 2d), four isothiocyanates (MeNCS 3a, EtNCS 3b, 'BuNCS 3c, M e3SiNCS 3d), one carbodiimide (Me3SiNCNSiM e3 4d), one keteneimine [Me3SiNCC(SiM e3)2 5d], two sulphinyl imides ('BuNSO 6c, M e3SiNSO 6d), and N-terf-butyl-pyrrole 7c, in order to determine coupling constants J (15N ,I3C) and isotope induced chemical shifts 1zAl2/13C (15N) at the natural abundance of the isotopes. The values 1 Z \I2/I3C (I5N) can be separated into two groups, one dealing with NC single and another one with NC double bonds. In each group (with few exceptions), the values 1A 2/13C (l5N) become more negative with a decrease in the absolute magnitude of l'7 (l5N ,13C)l. The corresponding values '2 r 4/l5N (l3C) show a sim ilar behaviour. However, N-substituted pyrroles appear to be exceptional in this respect. | | | |
Reference
| Z. Naturforsch. 53b, 411—415 (1998); received January 26 1998 | | | |
Published
| 1998 | | | |
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| default:Reihe_B/53/ZNB-1998-53b-0411.pdf | | | | Identifier
| ZNB-1998-53b-0411 | | | | Volume
| 53 | |
| 67 | Author
| Matthias Biedermanna, Helmut Hartung3, Heinz Böhlandb, Regina Matthäus | Requires cookie* | | | Title
| Koordinationsambidenz des Thiocyanations in Alkalitrithiocyanatomanganat(II)-Hydraten Coordination Ambidence of the Thiocyanate Anion in Alkali Trithiocyanatomanganate(II) Hydrates | | | | Abstract
| Alkali Thiocyanatomanganate(II) Hydrates, Crystal Structure, Coordination Ambidence Alkali metal trithiocyanatomanganate(II) hydrates have been prepared and characterized by several analytical methods. The structures of NH4[Mn(NCS)3(H20)] (la), K [M n(NCS)3(H20)] (lb) and Na[M n(NCS)3] • 3 H20 (2) could be elucidated by X-ray analysis, la and lb are isotypic and form a polymeric layer structure which is characterized by the ambident nature of the thiocyanate ligand and binding of the water molecule to the octahedrally coordinated Mn atom. In 2 the complex manganate(II) anions form a layer structure with trigonal symmetry in which each Mn atom is connected with three Mn neighbours by thiocyanate double bridges. The cation partial lattice consists of infinite chains of face-sharing [Na(H20) 6]+ octahedra running perpendicular to the anion layers. | | | |
Reference
| Z. Naturforsch. 53b, 416—422 (1998); eingegangen am 28. Januar 1998 | | | |
Published
| 1998 | | | |
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| default:Reihe_B/53/ZNB-1998-53b-0416.pdf | | | | Identifier
| ZNB-1998-53b-0416 | | | | Volume
| 53 | |
| 68 | Author
| Horst Kunkely, Amd Vogler | Requires cookie* | | | Title
| Charge Transfer Interaction in (Riboflavin)tricarbonylrhenium(I) Chloride | | | | Abstract
| Charge Transfer, Rhenium Complexes, Riboflavin [Re(riboflavin)(CO)3Cl] shows intraligand (Amax = 476 and 518 nm) and Re(I) to 7r* (riboflavin) metal-to-ligand charge transfer, MLCT, (Amax = 556 nm, in CH^CN) absorptions in close proximity. The MLCT band undergoes a moderate solvent-dependent shift (negative solvatochromism) indicating a partial charge separation in the excited state. The complex is not photoluminescent. | | | |
Reference
| Z. Naturforsch. 53b, 423—425 (1998); received February 5 1998 | | | |
Published
| 1998 | | | |
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| default:Reihe_B/53/ZNB-1998-53b-0423.pdf | | | | Identifier
| ZNB-1998-53b-0423 | | | | Volume
| 53 | |
| 69 | Author
| Rolf Minkwitz, Stefan Schneider | Requires cookie* | | | Title
| Die Tieftemperaturkristallstruktur von Trimethylsilanol The Low Temperature Crystal Structure of Trimethylsilanol | | | | Abstract
| A preparation of trimethylsilanol by hydrolysis of bis(trimethylsilyl)carbonate in diethylether at -2 0 °C is reported. At -8 0 °C, the crystals are monoclinic, space group P2,/c, Z = 12 with cell dimensions a = 996.0(2) pm, b = 1730.2(3) pm, c = 1122.9(2) pm, ß = 96,61(3)°. There are three independent Me3SiOH units with a slightly distorted tetrahedral C3SiO core structure. | | | |
Reference
| Z. Naturforsch. 53b, 426 (1998); eingegangen am 5. Dezember 1997 | | | |
Published
| 1998 | | | |
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| default:Reihe_B/53/ZNB-1998-53b-0426.pdf | | | | Identifier
| ZNB-1998-53b-0426 | | | | Volume
| 53 | |
| 70 | Author
| GeraldL. Wegner, AlexanderJockisch Hubert Schmidbaur | Requires cookie* | | | Title
| Synthesis and Structure of Benzyltriethylammonium Trichlorogermanate(II) | | | | Abstract
| Germanium Dichloride, Trichlorogermanate(II) The reaction of equimolar quantities of G eC h • dioxane with [BzEt3N]+ C P in tetrahydro-naphthaline gives high yields of [BzEt3N]+ [G eC h]~. The asymmetric unit of the monoclinic single crystals (from CH 2 CI2 , space group P2i/c, Z = 8) are comprising two pairs of crystallo graphically independent cations and anions, each with very similar molecular dimensions. The isolated [G eC b]-anions have a trigonal pyramidal structure with narrow Cl-Ge-Cl angles in the range from 93.41(5) to 98.27(5)° and Ge-Cl distances between 2.293(2) and 2.305(2) A. This structure is thus very similar to that of the isoelectronic A sCb molecule and of the [SeCl3 ]+ cation. | | | |
Reference
| Z. Naturforsch. 53b, 430—33 (1998); received January 30 1998 | | | |
Published
| 1998 | | | |
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| default:Reihe_B/53/ZNB-1998-53b-0430.pdf | | | | Identifier
| ZNB-1998-53b-0430 | | | | Volume
| 53 | |
| 71 | Author
| Gabriele Korus, Martin Jansen | Requires cookie* | | | Title
| Kristallstruktur von Natriumtrifluormethylsulfonat- Trifluormethylsulfonsäure (1/3) Studies on Sodium Trifluoromethanesulfonate. Crystal Structure of Sodium Trifluoromethanesulfonate-Trifluoromethanesulfonic Acid (1/3) | | | | Abstract
| Single crystals of sodium trifluoromethanesulfonate-trifluoromethanesulfonic acid (1/3) (N aS 0 3CF3 • 3 H S 0 3CF3) have been prepared by reaction of sodium trifluoromethanesulfonate with anhydrous trifluoromethanesulfonic acid at 60 °C. N aS 0 3CF3 • 3 H S 0 3CF3 crystallizes in space group 1 2 ^ (No. 199) with a = 16.210(1) A, Z = 8. Sodium is coordinated by six oxygen atoms from six different trifluoromethanesulfonic acid molecules, each acid molecu le connecting two sodium ions. The 3-dimensional network resulting from the edge sharing octahedra corresponds to the cubic (10, 3) net, not realised otherwise, so far. The trifluorome thanesulfonate anion is bonded to three trifluoromethanesulfonic acid molecules by hydrogen bonds. | | | |
Reference
| Z. Naturforsch. 53b, 438—442 (1998); eingegangen am 19. Dezember 1997 | | | |
Published
| 1998 | | | |
Keywords
| Sodium Trifluoromethanesulfonate, Sodium Triflate, Trifluoromethanesulfonic Acid, Synthesis, Crystal Structure | | | |
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| default:Reihe_B/53/ZNB-1998-53b-0438.pdf | | | | Identifier
| ZNB-1998-53b-0438 | | | | Volume
| 53 | |
| 72 | Author
| Z. Naturforsch | Requires cookie* | | | Title
| Ein weiteres 2A5,4A5-Diphosphapyridin: 2,2,4,4-Tetrakis-(dimethylamino)-6- amino-l-aza-2A5,4A5-diphosphinin | | | | Abstract
| A Further 2A5,4A5-Diphosphapyridine: 2,2,4,4-Tetrakis-(dimethylamino)-6-amino-1-aza-2A5,4A5-diphosphinine.-(dimethylamino)-6-amino-l-aza-2A5,4A5-diphosphinine (3) has been pre pared by reacting l,l,3,3-tetrakis(dim ethylam ino)-lA 5-3A:'-diphosphete (1) with bis(trimethyl-silyl)carbodiimide (2) in a 2 : 1 molar ratio. Properties, 'H, P, and l3C NMR, mass, and IR spectra are reported and discussed. Com pound 3 is further characterized by X-ray structure analysis. | | | |
Reference
| Z. Naturforsch. 53b, 443—147 (1998); eingegangen am 12. Dezember 1997 | | | |
Published
| 1998 | | | |
Keywords
| A5-Diphosphete, l-Aza-2A5, 4A5-diphosphinine, NMR Spectra, X-Ray Data 2, 2, 4, 4-Tetrakis | | | |
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| default:Reihe_B/53/ZNB-1998-53b-0443.pdf | | | | Identifier
| ZNB-1998-53b-0443 | | | | Volume
| 53 | |
| 73 | Author
| Andreas Böhm, Kurt Polborn, Karlheinz Sünkel, Wolfgang Beck | Requires cookie* | | | Title
| Metallkomplexe mit biologisch wichtigen Liganden, CIV [1]. or/Zio-Palladierte Komplexe von N,N-DimethyI-C-phenyl-glycinmethylester. Synthese von a-Aminosäure-Derivaten durch Insertion von Isocyaniden, CO, Alkenen und Alkinen in die Pd-C-Bindung Metal Complexes of Biologically Important Ligands, CIV [ 1]. o/t/20-Palladated Complexes of N,N-Dimethyl-C-phenylglycine-methylester. Synthesis of ct-Amino Acid Derivatives by Insertion of Isocyanides, CO, Alkenes, and Alkynes into the Pd-C Bond | | | | Abstract
| -phenylglycinemethylester reacts with Pd(OAc)2 in acetic acid to give the orthopalladated, acetato bridged complex 1. Treatment of 1 with sodium halide affords the chlo-ro, bromo, and iodo bridged compounds [Me2N C (H)(C 02Me)C6H4PdX]2 (2a -c) (X = halide). From 2a and 1,1 '-bis(diphenylphosphino)ferrocene the phosphine bridged trinuclear complex 3 is obtained. Substitution of the amine ligand of 2a by the phosphino group is observed for the reaction of 2a with Ph2PC(Me)C(Me)PPh2. Insertion of 2,6-dimethyl-phenylisocyanide, CO, alkyl-vinyl-ketones, and diphenylacetylene into the Pd-C bond o f 2a -c provides the ortho substituted organic and organometallic derivatives of phenylglycine 6a -c, 7, 8a -b and 9a -c. The crystal structures of 1, 4a, 6a, 7 and 9a were determined by X-ray diffraction. | | | |
Reference
| Z. Naturforsch. 53b, 448—458 (1998); eingegangen am 19. Dezember 1997 | | | |
Published
| 1998 | | | |
Keywords
| Palladium(II) Complexes, ortho-Palladation, N, N-Dimethyl-C-phenylglycine, Insertion Reactions N, N-Dimethyl-C | | | |
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| default:Reihe_B/53/ZNB-1998-53b-0448.pdf | | | | Identifier
| ZNB-1998-53b-0448 | | | | Volume
| 53 | |
| 77 | Author
| VladimirA. Ovchynnikov3, VladimirM. Amirkhanov3 ', TarasP. Timoshenko3, Tadeusz Glowiakb, Henryk Kozlowskib | Requires cookie* | | | Title
| Carbacylamidophosphates: Synthesis, Properties, and Structure of Dimorfolido-N-trichloroacetylphosphorylamide | | | | Abstract
| Dimorpholido-N-trichloroacetylphosphorylamide: CCl3C(0)NHP(0)[N(CH2CH2)2 0 ] 2 [HL] and its sodium [NaL] and morpholine [HN(CH2CH2) 2 0 HL] salts were synthesized for the first time. The compounds were studied by IR spectroscopy and assignments of the characteristic IR bands have been made. The structure of [HL] was determined by X-ray diffraction. Crystals are monoclinic, a = 11.412(2) A, b = 16.056(3) A, c = 9.622(2) Ä, ß = 108.55(3)°, space group P2i/c; Z = 4. The refinement of the structure converged at R = 0.066. The molecules are connected into centrosymmetric dimers via hydrogen bonds formed by the phosphorylic oxygen atoms and hydrogen atoms of amide groups. | | | |
Reference
| Z. Naturforsch. 53b, 481—484 (1998); received November 11 1997 | | | |
Published
| 1998 | | | |
Keywords
| Carbacylamidophosphates, IR Data, X-Ray Data | | | |
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| default:Reihe_B/53/ZNB-1998-53b-0481.pdf | | | | Identifier
| ZNB-1998-53b-0481 | | | | Volume
| 53 | |
| 79 | Author
| A., H. El, M. Aleem, Hussein Ostafa | Requires cookie* | | | Title
| Utility of Cyano Acid Hydrazide in Heterocyclic Chemistry: A New Route for the Synthesis of New l,2,4-Triazolo[l,5-a]pyridines and l,2,4-Triazolo[l,5-a]isoquinolines | | | |
Reference
| Z. Naturforsch. 53b, 488 (1998) | | | |
Published
| 1998 | | | |
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| default:Reihe_B/53/ZNB-1998-53b-0488.pdf | | | | Identifier
| ZNB-1998-53b-0488 | | | | Volume
| 53 | |
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