ISSN:
0018-019X
Schlagwort(e):
Chemistry
;
Organic Chemistry
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
Crystals of lithium purpurate dihydrate are triclinic, a = 6.715, b = 6.822, c = 14.038 Å, α = 96.85, β = 100.94, γ = 67.41°, space group P1, Z = 2. From the results of a detailed three-dimensional analysis the lithium ion is found to be bonded to three atoms (two oxygen plus central nitrogen) of one purpurate anion, and also to an oxygen atom of a second purpurate anion and to a water molecule to complete a roughly square-pyramidal 5-coordination. The purpurate anion is markedly nonplanar, the two six-membered rings being twisted by 22° around the central C—N bonds. A molecular mechanics calculation, based on reasonable interatomic potential functions, reproduces the observed geometry of the lithium complex and indicates that with larger cations the degree of out-of-plane twisting should increase. The observed dependence of the characteristic long-wave absorption of purpurate complexes on ionic radius is explained qualitatively on the basis of simple HMO-theory.
Zusätzliches Material:
7 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/hlca.19720550537
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