Spectroscopic Characterization of Molybdenum Dinitrogen Complexes Containing a Combination of Di- and Triphosphine Coligands:31P NMR Analysis of Five-Spin Systems

Reaction of the three vacant complex ofa-[P2W15O56]12-anda-[As2W15O56]12-with divalent cation of VO2+in 1:1 mole ratio yields a previously unknown sandwich-type Wells-Dawson complex; Na18[(NaOH)2(VO)2(P2W15O56)2].40H2O (represented as Na2(VO)2P4W30) and Na18[(NaOH)2(VO)2(As2W15O56)2].27H2O (represented as Na2(VO)2As4W30). These complexes contain anions in which two divalent VO2+cations with two Na+ions are symmetrically sandwiched between two α-[P2W15O56]12- or α-[As2W15O56]12-groups leading to a “lacunary” sandwich complex. The anion complexes are isolated as sodium salts and characterized by elemental analysis, TGA, IR, 31P NMR and UV-Vis spectroscopy.

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Spectroscopic characterization of nanoErythrosomes in the absence and presence of conjugated polyethyleneglycols: an FTIR and 31P-NMR study

Biochimica et Biophysica Acta (BBA) - Biomembranes ◽

10.1016/s0005-2736(02)00465-0 ◽

2002 ◽

Vol 1564 (2) ◽

pp. 317-324 ◽

Cited By ~ 12

Author(s):

Roxane Pouliot ◽

Audrey Saint-Laurent ◽

Camille Chypre ◽

Ritchie Audet ◽

Isabelle Vitté-Mony ◽

...

Keyword(s):

31P Nmr ◽

Spectroscopic Characterization ◽

Nmr Study

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Cluster-Linking Reactions: Synthesis and Structure of the Dicluster Complex [(Ph3P)2N]{Fe3(CO)9(.mu.3-PMe)(.mu.3-P)}2Au] and the Definitive 31P NMR Spectroscopic Characterization of Tricluster and Tetracluster Complexes in Oligomer Mixtures

Journal of the American Chemical Society ◽

10.1021/ja00084a064 ◽

1994 ◽

Vol 116 (5) ◽

pp. 2143-2144 ◽

Cited By ~ 12

Author(s):

Maria T. Bautista ◽

Peter S. White ◽

Cynthia K. Schauer

Keyword(s):

31P Nmr ◽

Spectroscopic Characterization

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Infrared, 57Fe Mössbauer, and 31P NMR Spectroscopic Characterization of Fe(CO)4L (L = Phosphine and Phosphite)

Zeitschrift für Naturforschung B ◽

10.1515/znb-1987-0510 ◽

1987 ◽

Vol 42 (5) ◽

pp. 573-578 ◽

Cited By ~ 15

Author(s):

Hidenari Inoue ◽

Takashi Nakagome ◽

Takeshi Kuroiwa ◽

Tsuneo Shirai ◽

Ekkehard Fluck

Keyword(s):

31P Nmr ◽

Chemical Shifts ◽

Spectroscopic Characterization ◽

Negative Slope ◽

Positive Slope ◽

Carbonyl Ligands ◽

Trigonal Bipyramidal ◽

Back Donation ◽

Donor Capability

A series of trigonal bipyramidal Fe(CO)4L complexes has been prepared and characterized by infrared, 57Fe Mössbauer and 31P NMR spectroscopy. A linear correlation, with a negative slope, between the CO stretching frequencies and the isomer shifts demonstrates that the triple bond nature of the carbonyl ligands is strengthened with increasing iron-to-phosphorus back donation. The linear dependence of the quadrupole splittings on the isomer shifts with a positive slope has revealed that the σ-donor capability of the phosphine or phosphite ligand is offset by the π-acceptor capability. The formation of Fe(CO)4L complexes from the corresponding free ligands is accompanied by a downfield shift of 31P NMR chemical shifts. The coordination shifts are linearly correlated with the Mössbauer isomer shifts.

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Mechanistic study of ligand substitution processes in TpIr(III) complexes

Canadian Journal of Chemistry ◽

10.1139/v00-162 ◽

2001 ◽

Vol 79 (5-6) ◽

pp. 525-528 ◽

Cited By ~ 5

Author(s):

David M Tellers ◽

Robert G Bergman

Keyword(s):

Kinetic Study ◽

Time Scale ◽

Methylene Chloride ◽

Spectroscopic Characterization ◽

Ligand Substitution ◽

Mechanistic Study ◽

Dissociative Mechanism ◽

Substitution Rates ◽

Dinitrogen Complexes

The synthesis of the cationic hydridotris(pyrazolyl)borate iridium(III) complex [Tp(PMe3)IrMe(ClCH2Cl)][BArf] (2-CH2Cl2) is reported. Spectroscopic characterization of 2-CH2Cl2 in CH2Cl2 solution indicates that exchange of bound CH2Cl2 with free CH2Cl2 is slow on the NMR time scale. Under 50 atm (1 atm = 101.325 kPa) of N2, the CH2Cl2 in 2-CH2Cl2 is displaced by N2 to yield [Tp(PMe3)IrMe(N2)][BArf] (2-N2). The stronger nucleophile CH3CN reacts rapidly with 2-CH2Cl2 to produce [Tp(PMe3)IrMe(NCCH3)][BArf] (4). A kinetic study was performed on CH2Cl2 substitution in 2-CH2Cl2 by CD3CN. The data are most consistent with dissociative loss of CH2Cl2 to generate the unsaturated species ([Tp(PMe3)IrMe][BArf]) which then reacts with CD3CN to generate [Tp(PMe3)IrMe(NCCD3)][BArf]. Further evidence for a dissociative mechanism was obtained by comparison of ligand substitution rates for the Tp complexes with the analogous TpMe2 complexes (TpMe2 = hydridotris(3,5-dimethylpyrazolyl)borate). The relevance of these substitution experiments to CH activation by cationic iridium(III) complexes is discussed.Key words: iridium, hydridotris(pyrazolyl)borate, methylene chloride and dinitrogen complexes, dissociative substitution.

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