Simple Trends in NMR Spectra of Vinyl Polymers: The1H NMR Spectrum of Poly(propylene)

2005 ◽  
Vol 206 (2) ◽  
pp. 203-209 ◽  
Author(s):  
Guglielmo Monaco ◽  
Adolfo Zambelli
2000 ◽  
Vol 78 (3) ◽  
pp. 383-394
Author(s):  
Frank Bottomley ◽  
Victor Sanchez ◽  
Robert C Thompson ◽  
Olusola O Womiloju ◽  
Zhiqiang Xu

Reduction of [(η-C5Me5)MoCl(O)]2(μ-O) or (η-C5Me5)MoCl2(O) with sodium or magnesium amalgam, magnesium turnings, or tributyltin hydride produced [(η-C5Me5)Mo]4O7, with [(η-C5Me5)Mo(O)(μ-O)]2 as a co-product. [(η-C5Me5)Mo]4O7 was characterized by X-ray diffraction, mass spectrometry, 1H NMR and IR spectroscopies, and magnetism. Crystals of [(η-C5Me5)Mo]4O7 contained a tetrahedral [(η-C5Me5)Mo]4 unit (Mo-Mo = 2.909 (3) Å) with the Mo4O7 core having the structure Mo4(μ2-O(b))3(µ2-O(c))3(µ3-O(a)) (3). Microcrystalline samples of [(η-C5Me5)Mo]4O7 were paramagnetic over the temperature range 2-300 K, with an effective moment of 1.26 μB at 300 K. [(η-C5Me5)Mo]4O7 was also paramagnetic in chloroform solution, over the temperature range 223-298 K, with an effective moment of 1.43 µB at 298 K. The 1H NMR spectrum showed a broad resonance at 16.3 ppm (Δν 1/2 = 113 Hz) and two narrow resonances at 1.89 ppm and 1.69 ppm (Δν 1/2 = 5 Hz). The magnetism and NMR spectra showed that [(η-C5Me5)Mo]4O7 existed in two forms which were in equilibrium in solution. One form was paramagnetic (S = 1), with the Mo4O7 core having the geometry 3, and the other was diamagnetic (S = 0), with the Mo4O7 core having the geometry 4.Key words: cluster, cyclopentadienyl, molybdenum, oxide, paramagnetism.


1994 ◽  
Vol 49 (6) ◽  
pp. 763-769 ◽  
Author(s):  
Monika Fritz ◽  
Johann Hiermeier ◽  
Frank H. Köhler

Two isomers of tetrahydro-4,4,8,8-tetramethyl-4,8-disila-s-indacene (LH2) were monodeprotonated and treated with cyclopentadienyl anion and NiBr2(THF)1,5 to give a 72% yield of the mixed nickelocene CpNi(LH) where a cyclopentadiene is fused to a nickelocene. The analysis of the paramagnetic 1H, 13C, and 29Si NMR spectra demonstrated that the syn and anti isomer of CpNi(LH) formed in a ratio of 5/1. Both isomers could be deprotonated to yield the anion CpNi(L-). According to its 13C NMR spectrum the bridging ligand L is not planar


2004 ◽  
Vol 205 (10) ◽  
pp. 1327-1337 ◽  
Author(s):  
Guglielmo Monaco ◽  
Rosario G. Viglione
Keyword(s):  

1992 ◽  
Vol 47 (6) ◽  
pp. 755-759 ◽  
Author(s):  
Thomas Kaukorat ◽  
Peter G. Jones ◽  
Reinhard Schmutzler

The 1H NMR spectrum of the spirophosphorane 3 at room temperature indicates dynamic behaviour of the cation. The low-temperature 1H NMR spectra of 3 exhibit two sets of doublets for the protons of the diastereotopic N(CH3)2 groups. The free enthalpy of activation for the dynamic process was determined (58.6 KJ/mole). In the reaction of 3 with sodium tetraphenylborate the crystalline compound, 4, involving the non-coordinating anion, [B(C6H5)4]-, was obtained. The X-ray crystal structure analysis of 4 reveals the presence of a five-membered ring, formally as a result of intramolecular donor-acceptor interaction between the nitrogen atom of the N(CH3)2 group and phosphorus. The geometry at phosphorus deviates somewhat from ideal trigonal bipyramidal.


1998 ◽  
Vol 53 (8) ◽  
pp. 829-832 ◽  
Author(s):  
H. Thomsen ◽  
W. Preetz

Abstract By reaction of closo-[B6H5F]2- in alkaline solution with excess iodine the monofluoropentaiodo- closo-hexaborate anion [B6FI5]2- is formed in good yield. The crystal structure of (CH2Py2)[B6FI5] has been determined by single crystal X-ray diffraction analysis (orthorhombic, space group Pnma, a = 13.803(2), b = 11.759(2), c = 13.936(2) Å, Z = 4). The B-F-bond length is 1.41 Å, the B-I distances range from 2.13 to 2.17 Å, the B-B distances from 1.69 to 1.76 A. According to the C4v point symmetry the 11B NMR spectrum of the anion exhibits three singlets at +3.8,-30.1 and-33.3 ppm with the intensity ratio 1:4:1, the 19F NMR spectrum one quartet at -247.6 ppm with the coupling constant 1J (19F, 11B) = 54 Hz.


1990 ◽  
Vol 210 ◽  
Author(s):  
S.G. Greenbaum ◽  
Y.S. Pak ◽  
K.J. Adamic ◽  
M.C. Wintersgill ◽  
J.J. Fontanella

AbstractThe results of several investigations of solvent-free polymer electrolytes by nuclear magnetic resonance (NMR) spectroscopy conducted by the authors and other groups are reviewed. 23Na NMR spectra of a wide variety of amorphous polymer electrolytes are characteristic of the second-order quadrupole broadened central ± 1/2 transition with a distribution of quadrupole couplings. The temperature dependence of the linewidth is similar across a wide range of materials, and highlights the importance of polymer segmental motions above the glass transition temperature to ion mobility. Strong cation-anion interactions in poly(propylene oxide) complexes are indicated by measurements of mobile ion concentrations and, in some cases, the observation of salt precipitation at elevated temperature.


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