Molecular Complexes, 13. Weak Arene Complexes of Nitroaromatics. 1H NMR Studies of Conformations and Polar Effects. syn-anti Selectivity of 5-Nitrofurfural
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Helmut Stamm
, Hanns-Otto Strumm
The refined 1H NMR method (AUS concept, CCl4) provided association constants K and approximate complex shifts IK for complexes of nitroaromatics A with aromatic hydrocarbons D. 5-Nitrofurfural (1) and benzene (B) or toluene (T) form syn-1B or syn-1T, respectively; a proton dependence of K indicates about 10% anti complexes. The dimer T2 of T additionally yields some 1T2 since IK values are 29-34% higher than for 1B. With naphthalene (N) or phenanthrene all protons of 1 provide the same K. Picrylacetone (2) and B form 2B and at least one 2BB adduct; published parameters of 2B and 2BB are inconsistent. 2 and N or M (1,3,5-trimethylbenzene) form only 1:1 complexes. All results are in accord with CH2COMe standing perpendicular to picryl. 2,4-Dinitrophenylacetone (3) in a rather flat conformation coordinates with a single stacking N centred over C-6; 3 yields two isomeric stacking complexes 3B and at least one edge-on 3B complex. 2-Chloro-5-nitropyridine (5) forms stacking complexes under repulsion of D by the ring N. In contrast to 1 and 4-nitrobenzaldehyde (6) 1,4-dinitrobenzene (7) and T form only a 1:1 complex that is stabilized by dipole-dipole attraction. Equal and unequal shielding of proton pairs (ortho or meta) in complexes of type 6B is discussed.
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- Synthesis and Structure of 1,3-Diisopropyl-4,5-dimethylimidazolium N,N'-Diphenylureate
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- Ternary Antimonides YbTSb (T = Ni, Pd, Pt, Cu, Ag, Au) – Synthesis, Structure, Homogeneity Ranges, and 121Sb Mössbauer Spectroscopy
- Studies of Monothiomalonamide and its Palladium(II) and Platinum(II) Complexes
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- Isomerisation of Alkenes Bearing Stannyl and Boryl Groups at the C=C Bond
- Tetrapodal Pentadentate Ligands with NS4 and NP4 Donor Sets: An Elusive Tetrathiol, and a Sterically Encumbered Tetraphosphane
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- Kinetic Studies of Condensation of Aromatic Aldehydes with Meldrum’s Acid
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Articles in the same Issue
- A Pyrazine-Bridged Ni(II) Coordination Polymer
- Synthesis and Structure of 1,3-Diisopropyl-4,5-dimethylimidazolium N,N'-Diphenylureate
- Darstellung und Thermolyse tert-butylsubstituierter Silatetrazoline – Erzeugung der Silanimine tBu2Si=N-SiXtBu2 (X = F, Cl, Br, tBu) Synthesis and Thermolysis of the tert-Butyl-Substituted Silatetrazolines – Formation of the Silanimines tBu2Si=N-SiXtBu2 (X = F, Cl, Br, tBu)
- Synthesis and Reactivity of Cyclopentadienyl and Indenyl Ligands Bearing ω-Fluorinated Pendant Groups. Crystal Structure of (ortho-F-C6H4)-CPh2-C5H4SiMe3
- Ternary Antimonides YbTSb (T = Ni, Pd, Pt, Cu, Ag, Au) – Synthesis, Structure, Homogeneity Ranges, and 121Sb Mössbauer Spectroscopy
- Studies of Monothiomalonamide and its Palladium(II) and Platinum(II) Complexes
- Synthese, Kristallstruktur und Spektroskopische Charakterisierung des Phosphaniminato-Komplexes [Cl2AlNPCl3]2 und des Phosphanimin-Komplexes [Me3SiNPCl3 · AlCl3]/Synthesis, Crystal Structure, and Spectroscopic Characterization of the Phosphorane Iminato Complex [Cl2AlNPCl3]2, and of the Phosphane Imine Complex [Me3SiNPCl3 · AlCl3]
- Magnetic Exchange Based on π-π Stacking Interactions: Synthesis, Crystal Structure, Thermal Decomposition and Magnetic Properties of [Ce(phen)2(H2O)2(NO3)2](NO3)(phen)2(H2O)
- Isomerisation of Alkenes Bearing Stannyl and Boryl Groups at the C=C Bond
- Tetrapodal Pentadentate Ligands with NS4 and NP4 Donor Sets: An Elusive Tetrathiol, and a Sterically Encumbered Tetraphosphane
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- Kinetic Studies of Condensation of Aromatic Aldehydes with Meldrum’s Acid
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