- The Crystal Structures of (1,5-Ditolylpentaazadienido)(triphenylphosphane)gold(I) and 1,5-Ditolyl-3-methylpentaazadiene
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PPH3Au(tolN5tol) is obtained by the reaction of PPh3Au(+)ClO4(-) with Tl(tolN5tol).It crystallizes in the monoclinic space group P21/c with the lattice parameters a = 1548.8(5), b = 1070.7(2), c = 1779.1(3) pm, β = 90.33(2) deg, Z = 4.In the monomeric complex the gold atom is nearly linearcoordinated by the phosphorus atom of the PPh3 group and nitrogen atom N3 of the pentaazadienido ligand (N3-Au-P 178.4 deg). tolNN(NCH3)NNtol crystallizes in the orhtorhombic space group Pccn with the lattice constants a = 2426.7(9), b = 469.3(2), c = 1195.3(4) pm.The unit cell contains four molecules, located on twofold axes.Due to the isolobality of the CH3 and the PPh3Au group, the two structures are closely related.Both contain the typical planar zig-zag chain of five nitrogen atoms with located double bonds N1-N2 and N4-N5 (from 119.8 to 126.6 pm) and shortened single bonds N2-N3 and N3-N4 (132.7 to 140.0 pm). - Keywords: (1,5-Di-p-tolylpentaazadienido)(triphenylphosphane)gold(I), 1,5-Ditolyl-3-methylpentaazadiene, Synthesis, Crystal Structure
- Beck, Johannes
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p. 1219 - 1223
(2007/10/02)
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- 13C and 1H Nuclear Magnetic Resonance Study of Solvent Effects on Tautomerism in 1-Aryl-3-methyltriazenes
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13C and 1H n.m.r. spectra of 1-p-tolyl- (II) and 1-p-nitrophenyl-3-methyltriazene (III) have been recorded in CDCl3 at variable temperatures and in DMSO solutions at ambient temperature.Assignment of 13C and 1H signals to one or both of the tautomeric species (ArN=N.NHCH3 or ArNH.N=NCH3) has been carried out with the aid of gated decoupling and full 1H decoupling methods and by comparison of chemical shifts with those of the model compounds p-nitroaniline, 3,3-dimethyl-1-p-nitrophenyltriazene, and 3-methyl-1,5-di-(p-tolyl)-pentaza-1,4-diene(IV).The 13C spectrum of(II) in CDCl3 shows signals assigned to the conjugated tautomer (IIa), but not the unconjugated tautomer (IIb); additional signals in the 13C spectrum of (II) are shown to arise from the pentaazadiene (IV), which is present as an impurity (ca. 10percent) in commercial samples of (II). 1H and 13C spectra of (IV) have been completely assigned.The tautomeric equilibrium (IIa) -->/DMSO as solvent, so much so that two full sets of aromatic peaks are visible in the 13C spectrum of (II) in DMSO at room temperature and the 1H spectrum clearly shows signals unequivocally assigned to the unconjugated tautomer (IIb).The equilibrium (IIa) -->//DMSO and the 1H spectra of (III) in DMSO and the 1H spectra of (III) in DMSO or in CDCl3 at room temperature also show the presence of both tautomers.The relative proportions of tautomers (IIIa) : (IIIb) was found to be 49 : 51 in DMSO.
- Hooper, Donald L.,Vaughan, Keith
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p. 1161 - 1165
(2007/10/02)
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