Ekkehard Fluck

Spin-1 NMR

The Basic Physics of Spin-1 Systems.- 1.1 General Introduction.- 1.2 Spin States and Matrix Representations of Operators for Spin-1.- 1.3 Spin-1 Operator Algebra.- 1.4 Lowdin Projectors for Spin-1.- 1.5 Interactions Relevant in Spin-1 NMR.- 1.6 Pulse Rotations.- 1.7 Density Matrix Description of the State of Spin-1 Ensembles.- 1.8 Evolution of the Spin-1 System Under Quadrupolar Coupling.- 1.9 Phase Changes of Spin-1 Wavefunctions Under Rotation.- 1.10 Evolution of the Spin-1-Spin-1/2 System Under Scalar Coupling.- 1.11 Spin Tickling in a Spin-l/2-Spin-l Scalar Coupled System.- 1.12 Evolution of the Spin-l-Spin-1 System Under Scalar Coupling.- 1.13 Coherence Transfer Function for Spin-1 Systems.- 1.14 Quadrupolar Relaxation.- 1.15 Spin-1 Behavior of Two Equivalent Spins-1/2.- NMR of Systems Involving Spin-1 Nuclei in the Isotropic Phase..- 2.1 Chemical Shift Information.- 2.2 General Spectral Features Consequent on Coupling to Spin-1.- 2.3 Laboratory Frame Polarization Transfer Involving Spin-1 Nuclei.- 2.4 INEPT Polarization Transfer from Spin-1 (S) to Spin-1/2 (I).- 2.5 DEPT Polarization Transfer from Spin-1 (S) to Spin-1/2 (I).- 2.6 Polarization Transfer from Spin-1/2 (I) to Spin-1 (S).- 2.7 Pulse Width Calibration for Polarization Transfer Experiments.- 2.8 Polarization Transfer Between Spin-1 Nuclei.- 2.9 Two-Dimensional Experiments Involving Spin-1 Nuclei.- 2.10 Correlation Spectroscopy (COSY).- 2.11 Heteronuclear Multiple Quantum Spectroscopy.- 2.12 Homonuclear Multiple Quantum Spectroscopy.- 2.13 Relayed Correlation Spectroscopy.- 2.14 Instrumentation for High Resolution Spin-1 NMR.- 3 NMR of Spin-1 Systems in the Solid State.- 3.1 Introduction.- 3.2 Quadrupolar Echo.- 3.3 Jeener-Broekaert Sequence.- 3.4 Deuterium NMR Spectroscopy of Single Crystal Systems.- 3.5 Two-Dimensional Deuterium COSY Spectra in the Solid State.- 3.6 Deuterium NMR Under Magic Angle Spinning.- 3.7 Double Quantum Spectroscopy.- 3.8 QUADSHIFT Experiment.- 3.9 Overtone Spectroscopy.- 3.10 Spin-1/2-Spin-1 Dipolar Coupling.- 3.11 Spin Alignment.- 3.12 Deuterium Exchange Spectroscopy in Single Crystals.- 3.13 Deuterium Exchange Spectroscopy.- 3.14 Spin-1 Double Quantum Imaging.- 3.15 Instrumentation for Solid State NMR.- 4 Reference.

1.1.3.3-Tetrakis(dimethylamino)-1λ5,3λ5-diphosphet / 1.1.3.3-Tetrakis(dimethylamino)-1λ5,3λ5-diphosphete

The title compound 1 was prepared by reacting methyl-bis(dimethylamino)difluorophosphorane with butyllithium at -95 °C. The crystalline product is characterized by its NMR and IR spectra. The results of the X-ray crystal and molecular structure analyses are reported.

REAKTIONEN VON P-FLUOR-YLIDEN MIT BASEN

Abstract Die Reaktion der P-Fluorylide 1–7 mit Alkyllithium oder Lithium-bis(trimethyIsily1)amid fuhrt zu den neuen Phosphor-Yliden 8a und 10a, den neuen Phosphiranen 9, l2, 14 und 15 sowie zu dem neuen 1λ5,3λ5-Diphosphet 13. Alle Verbindungen sind durch physikalische Eigenschaften und ihre NMR-, Massen- und IR-Spektren charakterisiert. Reaction of P-fluoroylids 1–7 with alkyllithium or lithium bis(trimethylsilyl)amide yields the phosphorus ylids 8a and 10a, the new phosphiranes 9, 12, 14 and 15 as well as the new 1λ5,3λ5-diphosphete 13. All compounds are characterized by physical properties and their nmr, mass, and ir spectra.

DIE REAKTION VON 1,1,3,3-TETRAKIS(DIMETHYLAMINO)-1Λ5,3Λ5-DIPHOSPHET MIT ACETONITRIL

Abstract Reaction of 1,1,3,3-tetrakis(dimethylamino)-1Λ5,3Λ5-diphosphete 1 with acetonitrile yields 3,3,5,5-tetrakis(dimethylamino)-3,5-diphospha-hexa-2,4-dienenitrile, 2. Properties, NMR spectra and the results of an X-ray structural analysis are reported. Die Umsetzung von 1,1,3,3-Tetrakis(dimethylamino)-1Λ5,3Λ5-diphosphet 1 mit Acetonitril liefert 3,3,5,5-Tetrakis(dimethyl-amino)-3,5-diphospha-hexa-2,4-diennitril, 2. Eigenschaften, NMR-Spektren und die Ergebnisse einer Rontgenstrukturanalyse werden mitgeteilt.

REACTION OF 1,1,3,3-TETRAKIS(DIMETHYLAMINO)-1λ5,3λ5-DIPHOSPHETE, 1, WITH CARBONDISULFIDE II. DIHYDRO-λ5-PHOSPHETES; NMR ISOTOPE EFFECTS

Abstract 1,1,3,3-Tetrakis(dimethylamino)-1-phospha-3-phosphonium-2-dithio-carboxylato-cyclobutene-1, 2,1 is thermally unstable. By heating it is converted quantitatively into [1,1-bis(dimethylamino)-3-thioxo-3,4-dihydro-1λ5-phosphete-2-yl]-phosphonothioic bis(dimethylamide), 3. Reaction of the 2,4-dimethylderivative of the title compound 1, i.e. 4, with CS2 yields [1,1-bis(dimethylamino)-2,4-dimethyl-3-thioxo-2,3-dihydro-1λ5-phosphete-2-yl]-phosphonothioic bis(dimethylamide) 7. The new compounds are characterized by their properties and their nmr, it and mass spectra. Isotope effects on δ31P of 7 are described. The results of the X-ray structural analyses of 3 and 7 are reported and discussed.

o-λ5-[1,3]-Diphosphaphenylen-bis(diphenylphosphanoxid) und sein palladium(ii)-komplex

Abstract 4,5-Bis(diphenylphosphanoyl)-octa- N -methyl-1λ 5 ,3λ 5 -[1,3]-diphosphinin-1,1′3,3′-tetraamin ( o -λ 5 -[1,3]-diphosphaphenylene-bis(diphenyl-phosphanoxide)), 2 , is formed from compound 1 by aeration. Compound 2 acts as a chelating ligand owing to the anionic nature of two ylidic carbon atoms in the reaction with (benzonitrile) 2 PdCl 2 to form complex 3 . Compound 2 is characterized by its NMR and IR spectra, and compound 3 by the results of an X-ray structural analysis.

REAKTIONEN DES 1,1,3,3-TETRAKIS(DIMETHYLAMINO)-1λ5,3λ5- DIPHOSPHETS MIT CARBONYLAKTIVEN VERBINDUNGEN

Abstract Reaction of 1,l,3,3-tetrakis(dimethylamino)-lλ5,3λ5-diphosphete (1) with benzaldehyde yields [(2-phe-nyl-l-ethenyl)- bis(dimethylamino)phosphoranylidene]methylphosphonicbis(dimethylamide) (2), while 1 reacts with phenylisocyanate to give the heterocyclic compound 3, i.e., l-phenyl-2,2,4,4-tetrakis(dimethylamino)-6-oxo-l,2λ5,4λ5-azadiphosphorine. 2 and 3 are characterized by their nmr, mass, and i.r. spectra. In 3, the signs of the coupling constants 1J(PC2) and 3J(PC2) are found to be opposite. Mechanisms for the formation of 2 and 3 are discussed. 1,1,3,3-Tetrakis(dimethylamino)-lλ5,3λ5-diphosphet (1) reagiert mit Benzaldehyd zu [(2-Phenyl-1-ethenyl)-l-bis(dimethylamino)phosphoranyliden]methylphosphonsaurebis(dimethylamid) (2). Wahrend mit Phenylisocyanat die heterocyclische Verbindung 3. d.i. I-Phenyl-2,2,4,4-tetrakis-(dimethylamino)-6-oxo-l,2λ5,4λ5-azadiphosphorin gebildet wird. 2 und 3 sind durch ihre NMR-, Mas-sen- und IR-Spektren charakterisiert. In 3 haben die Kopplungskonstanten 1J(PC2) u...

Ein Derivat des 1λ5,3λ5,5λ3-Triphosphabenzols / A Derivative of 1λ5,3λ5,5λ3-Triphosphabenzene

Abstract The title compound was prepared by reacting 1,1,3,3-tetrakis(dimethylamino)-1λ5,3λ5-diphosphete with 2,2-dimethylpropylidynephosphane and characterized by NMR spectra and X-ray structure analysis.

Spectroscopic characterization of iron complexes of methyl pheophorbide with pyridine and its derivatives

Abstract A series of (methyl pheophorbide a)iron(II) and -iron(III) complexes have been prepared and characterized by Mossbauer, 1H NMR and electronic spectra. The central iron(III) ion in (methyl pheophorbide a)iron(III) chloride [Fe(mepheo-a)] is in the high-spin state. Autoreduction of the central iron(III) ion in Fe(mepheo-a)Cl is induced by pyridine (py) and its derivatives (4-Xpy). A connection between isomer shifts and quadrupole splittings of Fe(mepheo-a)(4-Xpy)2 indicates the σ-donation from the axial ligands to the central iron(II) ion is predominant in the axial bonding. The linear dependence of the isomer shifts on Hammetts constants of the pyridine substituents (X) and on the pKa values of the free ligands reveals that the, π-backdonation to the axial ligands enhances synergetically the σ-donation to the central iron(II) ion. The linear correlation between the isomer shift and the electronic absorption wavelength demonstrates that the difference in the π-backdonation to the axial ligands affects the π-π* excitations on the chlorin ring via the central iron(II) ion.

Phosphorus-Boron and Phosphorus-Silicon Ring Systems Functionalization of Phosphorus Ring Systems

Abstract The diphosphide K2[(t-Bu)P-BN(i-Pr)2-P(t-Bu)] reacts with t-BuPCl2 to form the P3B ring system (i-Pr)2NB(t-BuP)3 1. The five-membered P4B ring system (i-Pr)2NB(t-BuP)4 2 is formed from K2[(t-BuP)4] 3 and (i-Pr)2NBCl2 analogous to the above reaction. The reaction of 3 with SiCl4 or Si2Cl6 produces the novel five-membered ring systems (t-BuP)4SiCl2 4 or (t-BuP)4Si(Cl)SiCl3 5 respectively. New routes to the synthesis of the monofunctionalized cyclophosphanes (t-BuP)2PCl 6 and (t-BuP)3PCl 7 and to the new bifunctionalized cyclophosphane 1-Br-3-[(t-Bu)(Br)P]-2.4-(t-Bu)2-P4 8 will be reported. 1, 2, 4, and 7 could be characterized by X-ray structure analysis; the structures of 5 and 8 could be inferred from NMR data. The 31P NMR spectra of 2 and 7 indicate (10,11B) and (35,37Cl) isotopic shifts respectively.