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

2008 ◽  
Vol 47 (14) ◽  
pp. 6541-6550 ◽  
Author(s):  
Kristina Klatt ◽  
Gerald Stephan ◽  
Gerhard Peters ◽  
Felix Tuczek
Keyword(s):  
31P Nmr ◽  
Spectroscopic Characterization ◽  
Spin Systems ◽  
Nmr Analysis ◽  
Dinitrogen Complexes

scholarly journals Synthesis and Spectroscopic Characterization of Two New Dawson Sandwich Complexes: Na18[(NaOH)2(VO)2(P2W15O56)2].40H2O and Na18[(NaOH)2(VO)2(As2W15O56)2].27H2O

2012 ◽  
Vol 9 (4) ◽  
pp. 2185-2190 ◽  
Author(s):  
Mohammad Hakimi ◽  
Mohammad Reza Mohammadi ◽  
Salma Behboupour
Keyword(s):  
Divalent Cation ◽  
31P Nmr ◽  
Spectroscopic Characterization ◽  
Sandwich Complexes ◽  
Sandwich Complex ◽  
Sodium Salts ◽  
Vis Spectroscopy ◽  
Sandwich Type ◽  
Anion Complexes

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.

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

2002 ◽  
Vol 1564 (2) ◽  
pp. 317-324 ◽  
Author(s):  
Roxane Pouliot ◽  
Audrey Saint-Laurent ◽  
Camille Chypre ◽  
Ritchie Audet ◽  
Isabelle Vitté-Mony ◽  
...  
Keyword(s):  
31P Nmr ◽  
Spectroscopic Characterization ◽  
Nmr Study

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

1987 ◽  
Vol 42 (5) ◽  
pp. 573-578 ◽  
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.

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

2001 ◽  
Vol 79 (5-6) ◽  
pp. 525-528 ◽  
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 C—H activation by cationic iridium(III) complexes is discussed.Key words: iridium, hydridotris(pyrazolyl)borate, methylene chloride and dinitrogen complexes, dissociative substitution.

Spectroscopic Characterization of Bacteriorhodopsin's L-intermediate in 3D Crystals Cooled to 170 K¶

2001 ◽  
Vol 74 (6) ◽  
pp. 794 ◽  
Author(s):  
Antoine Royant ◽  
Karl Edman ◽  
Thomas Ursby ◽  
Eva Pebay-Peyroula ◽  
Ehud. M. Landau ◽  
...  
Keyword(s):  
Spectroscopic Characterization
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