The molecular and electronic structure of 1-pyrazolylphosphazenes

1992 ◽  
Vol 70 (6) ◽  
pp. 1855-1868 ◽  
Author(s):  
Keith D. Gallicano ◽  
Norman L. Paddock ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Electron Transfer ◽  
Pyrazole Ring ◽  
Crystal Data ◽  
Potential Donor ◽  
Good Potential ◽  
Pyrazolyl Group ◽  
D Orbitals ◽  
Extended Hückel Calculations ◽  
Molecular And Electronic Structure ◽  
Electronegative Group

The nature of the interactions between pyrazolyl and phosphazene rings has been investigated through the study of the structures of bis(1-pyrazolyl)methane, CH2(H2pz)2, 1, bis[1-(3,5-dimethylpyrazolyl)]methane, CH2(Me2pz)2, 2, the pyrazolylphosphazenes N3P3(Me2pz)6, 3, N4P4(H2pz)8, 4, and N4P4(Me2pz)8, 5, and the partially substituted gem-N3P3Ph2(Me2pz)4, 6. Crystal data are as follows: 1, orthorhombic, P212121, a = 7.997(2), b = 9.287(2), c = 10.049(2) Å, Z = 4, R = 0.034 for 647 reflections; 2, monoclinic, C2/c, a = 19.115(4), b = 4.2690(8), c = 14.543(3) Å, β = 98.91(2)°, Z = 4, R = 0.064 for 528 reflections; 3, monoclinic, C2/c, a = 16.778(2), b = 12.1083(9), c = 19.269(4) Å, β = 113.885(6)°, Z = 4, R = 0.039 for 2716 reflections; 4, monoclinic P21/n, a = 10.4223(9), b = 8.1879(7), c = 19.403(2) Å, β = 94.381(7)°, Z = 2, R = 0.059 for 2937 reflections; 5, triclinic, [Formula: see text], a = 11.516(2), b = 13.121(3), c = 18.142(3) Å, α = 77.96(1), β = 79.20(1), γ = 66.54(2)°, Z = 2, R = 0.036 for 5300 reflections; 6, monoclinic, P21/c, a = 10.3598(4), b = 17.8827(4), c = 19.0851(6) Å, β = 94.675(2)°, Z = 4, R = 0.053 for 4867 reflections. Interpretation of the structures through iterative extended Hückel calculations shows that conjugative interactions lead to a quinonoid deformation of the pyrazole ring, similar to that in bis(1-pyrazolyl)carbonyl. π-Electron transfer to the phosphazene ring, facilitated by the use of acceptor d orbitals on phosphorus, is accompanied by a synergic σ transfer to the pyrazole ring. The pyrazolyl group acts both as a strongly electronegative group and as a good potential donor. The calculations account satisfactorily for the bond lengths in the pyrazolyl group, the large bond angles at nitrogen in 4 and 5, the bond length inequalities in the phosphazene ring of 6, and the reactivity of the pyrazolylphosphazenes.

Coordination chemistry of dimethylgold(III) and methylmercury(II). Synthesis, 1H N.M.R. and structural studies of Poly(pyrazol-1-yl)borate complexes

1983 ◽  
Vol 36 (6) ◽  
pp. 1107 ◽  
Author(s):  
AJ Canty ◽  
NJ Minchin ◽  
JM Patrick ◽  
AH White
Keyword(s):  
Coordination Chemistry ◽  
Variable Temperature ◽  
Gold Atom ◽  
Pyrazole Ring ◽  
Structural Studies ◽  
Crystal Data ◽  
X Ray Diffraction ◽  
X Ray ◽  
Square Planar ◽  
Borate Complexes

Dimethylgold(III) and methylmercury(II) form complexes Me2AuL and MeHgL where L are poly-(pyrazol-1-yl)borate ligands [HB(pz)3]- and [B(pz)4]-. The structure of Me,Au{HB(pz)3} has been determined by single-crystal X-ray diffraction at 295 K and refined by least-squares methods to R 0.056 for 2194 independent 'observed' reflections. This complex has square-planar coordination for the gold atom involving two coordinated pyrazole rings and one uncoordinated ring, in contrast to the isoelectronic cation [Me2Au{(pz)3CH)]+ which has square planar coordination with a weak axial Au . .N interaction. Variable temperature 1H n.m.r. spectra in CD2Cl2 indicate presence of rapid equilibria between pyrazole ring environments at ambient temperature and, for the MeHgII complexes, down to -90�C. For the Me2AuIII complexes spectra at -90�C indicate presence of pyrazole ring environments in ratios 2 : 1 (L = [HB(pz)3]-) and 2 : 1 : 1 (L = [B(pz)4]-). Crystal data for Me2Au{HB(pz)3}: rhombohedral, space group R3c, a 17.98(1) �, α 117.98(5)�, Z 18.

Synthesis, Crystal Structure and Bio-Activity of 1-Phenyl-3-(2-Hydroxyl-Phenyl)-5-(2,4-Chloro-Phenyl)-2-Pyrazoline

2013 ◽  
Vol 648 ◽  
pp. 27-30
Author(s):  
Yin Zhi Jiang ◽  
Ya Yi Shi ◽  
Da Wei Liang
Keyword(s):  
Title Compound ◽  
Nmr Spectra ◽  
Three Dimensional ◽  
Pyrazole Ring ◽  
Molecular Field ◽  
Crystal Data ◽  
Inhibitory Effects ◽  
One Dimensional ◽  
X Ray ◽  
Electron Donating Groups

The title compound 1-Phenyl-3-(2-Hydroxyl–Phenyl)-5-(2,4-Chloro-Phenyl)-2-pyrazoline（C21H16Cl2N2O,Mr=383.26） was prepared from chalcone and phenylhydrazine. It was characterized by IR spectra, NMR spectra, MS spectra and X-Ray. The following crystal data was given: space group Pbca, with a=8.9678(7), b=14.1785(11), c=28.603(2)Å, β=90.00°, V=3636.8(5)nm3, Z=8, Dc=1.400mg/m3, μ=0.369mm-1, F(000)=1584, R=0.0492 and wR=0.1175. Found that there exist intramolecular H-bonds and the structure was one-dimensional lattice molecular. The inhibitory effects on EcMetAPof the title compound was determined and its inhibition was 31.62%. Its molecular field-based similarity analysis provided the necessary three-dimensional molecular field properties of the title compound to inhibit EcMetAP activities, and found that the EcMetAP inhibit-activities could be increased by addition electron donating groups at position 1,2 and 4 of pyrazole ring.

Molecular and electronic structure of electron-transfer active main-group organometallics

1989 ◽  
Vol 111 (6) ◽  
pp. 2126-2131 ◽  
Author(s):  
Jens Baumgarten ◽  
Christian Bessenbacher ◽  
Wolfgang Kaim ◽  
Thomas Stahl
Keyword(s):  
Electron Transfer ◽  
Electronic Structure ◽  
Main Group ◽  
Molecular And Electronic Structure

Molecular and electronic structure of the electron-transfer probe analog [trans-(NH3)4Ru(imidazole)(isonicotinamide)](CF3CO2)3.cntdot.2-propanol

1992 ◽  
Vol 31 (14) ◽  
pp. 3179-3181 ◽  
Author(s):  
James F. Wishart ◽  
Xiaohua Zhang ◽  
Stephan S. Isied ◽  
Joseph A. Potenza ◽  
Harvey J. Schugar
Keyword(s):  
Electron Transfer ◽  
Electronic Structure ◽  
Molecular And Electronic Structure

Photochromic Behaviour of N-Arylsulfonyl Peptides

2003 ◽  
Vol 2003 (8) ◽  
pp. 511-513 ◽  
Author(s):  
Roger R. Hill ◽  
Sharon A. Moore ◽  
David R. Roberts
Keyword(s):  
Amino Acids ◽  
Electron Transfer ◽  
Photoinduced Electron Transfer ◽  
Wide Range ◽  
Derivatives Of ◽  
D Orbitals

Deep, persistent, but structurally sensitive photoyellowing observed in photochemical studies of a wide range of arylsulfonyl derivatives of amines, amino acids and peptides can be attributed to a novel kind of photochromism in which intramolecular photoinduced electron transfer promotes the formation of a metastable cyanine-type chromophore involving sulfur d-orbitals.

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