Cyclotetraphosphanes: geometry, 1J(PP) nuclear magnetic resonance coupling constants, and phosphorus chemical shift anisotropy. A nuclear magnetic resonance study in liquid crystals

Abstract

The 31P |*H¡ or j19F¡ NMR spectral analysis of five cyclotetraphosphanes (RP)a (R = CH3, Z-Bu, Z-Pr, C2H5, c-CeHii) oriented by means of nematic phases is reported. The NMR spectrum in oriented phase allows us unambiguously to assign a tetrameric formula to the compounds under study. The ring puckering has been measured and shows a good agreement

Synthesis, Spectroscopic Properties, and Reactivity of Ferrocenyl(2,4,6-tri-tert-butylphenyl)diphosphene

“…Simulated and measured 31 P NMR spectra of 2 are in good accordance, using as a set of coupling parameters J AA ‘ / J BB ‘ = 127.6/±156.8 Hz and J AB / J AB ‘ = ±150.9/−64.8 Hz. Assuming an arrangement of substituents as shown in A , the coupling constants AA‘ and BB‘ would be of the type 2 J PP , which is in contradiction to the observed values revealing a 1 J PP coupling . Hence, a “head to tail” dimer can be excluded.…”

Versatile Coordination Chemistry of Hexa-tert-butyl-octaphosphine

“…Simulation of the NMR spectra was performed using the DAISY module implemented in the program TopSpin version 3.6.1 (Bruker, BioSpin GmbH, Rheinstetten). For this, the 1 J PP coupling constants were set negative …”

“…For this, the 1 J PP coupling constants were set negative. 56 X-ray Crystallography. Single crystal X-ray diffraction data were collected with a Gemini CCD diffractometer (Rigaku).…”

Palladium clusters. 4. Synthesis and 31P and 195Pt NMR study of a mixed platinum/palladium cation, [PtPd2Cl(PPh2)2(PPh3)3]+, and the crystal and molecular structures of [Pd3Cl(PPh2)2(PEt3)3] [BF4], [Pd3Cl(PPh2)2(PPh3)3][BF4], and [Pt0.81Pd2.19Cl(PPh2)2(PPh3)3] [BF4]

“…The most shielded resonance quoted by Kidd and Goodfellow in their recent review47 was that for the [Ptl6]2" ion at ppm. Second, we note the relatively large values (80)(81)(82)(83)(84)(85)(86)(87)(88)(89)(90) Hz) for the J(AB) coupling. In the absence of a metal-metal bond, this would be a four-bond coupling through a PPh2 bridge and thus could be compared to the 4/(PP) values (0-10 Hz) observed in the complexes [M2Cl2(PPh2)2(PR3)2],…”

“…Least-squares planes weighted according to the standard deviations of the atomic coordinates were calculated for the nine heavy atoms of compounds I-III, and the results are deposited 8) 7291 ( 7) 5803 ( 10) 64 (6) C( 58) 10841 ( 9) 11026 ( 6) 3980 ( 12) 119 (10) C( 13) 9201 ( 10) 5799 ( 7) 3000 ( 12) 59 (5) C( 59) 10152 ( 9) 10636 ( 6) 4119 ( 12) 140 (11) C( 14) 10126 ( 10) 5597 ( 7) 3476 ( 12) 82 (7) C( 60) 9636 ( 9) 10032 ( 6) 3325 ( 12) 95 (8) C( 15) 10373 ( 10) 5209 ( 7) 2728 ( 12) 106 ( 9) C( 61) 9984 ( 8) 8698 ( 6) 963 ( 11) 45 (5) C( 16) 9694 (10) 5023 ( 7) 1503 ( 12) 108 ( 9) C( 62) 10951 ( 8) 8673 ( 6) 1837 ( 11) 59 (5) C( 17) 8769 ( 10) 5224 ( 7) 1027 ( 12) 100 ( 8) C( 63) 11602 ( 8) 8427 (...…”