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The reaction of 2,2′-bipyridylamine (abbreviated BPAH) with divalent nickel salts results in the formation of several products, the type of which depends on the metal:ligand ratio and the coordinating ability of the associated anion. Thus, tetrahedral [Ni(BPAH)Cl2] and octahedral [Ni(BPAH)3] (ClO4)2 and [Ni(BPAH)2Cl2] have been isolated and characterized. In these complexes, dipyridylamine coordinates in a bidentate manner through the two pyridine nitrogens. Deprotonation of the amine at ambient temperature in butanol results in the conversion of the paramagnetic [Ni(BPAH)2Cl2] species into a six-coordinate polymeric material of the general formula Ni(BPA)2 where the deprotonated bipyridylamine moiety (ab¬breviated BPA) is coordinating in a tridentate manner with the amine nitrogen acting as a bridge. This polymer is cleaved quite readily by the action of water, pyridine, and, presumably, other complexing solvents. Deprotonation of [Ni(BPAH)-Cl2] at high temperatures in naphthalene or reaction of the deprotonated polymer with nickel(II) chloride, also at high temperatures, yields a red crystalline trinuclear complex of the molecular formula [Ni3(BPA)4Cl2]. Deprotonation of bis(2,2′-bipyridylamine)copper(II) chloride and bis(2,2′-bipyridylamine)palladium(II) perchlorate give the expected four-coordinate square-planar product. The deprotonated complexes of palladium, copper, and nickel are compared and corre¬lations are made between their ease of formation and the geometry and electronic arrangement of the central metal ion. © 1968, American Chemical Society. All rights reserved.
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Both negative and positive cultural factors affect innovative efforts in developing countries. In the case of Ethiopia, negative factors include a low esteem for craftsmanship. Even where modern education is making inroads on some negative factors, as in the towns, feudalistic attitudes toward labor and the preference for unskilled labor on the assumption that it is more economical, act to continue functionally inefficient attitudes. In contrast, positive factors exist in traditions of mutual aid, now spreading from South Ethiopian cultures northward. An excellent model for mutual aid may be found in the practices of the migrant weavers' association of the Gurage and some neighboring tribes. Ethiopia provides an interesting area for the study of human factors in developing countries since it has not passed through a colonial period. Various stages of development can be traced comparatively free of outside influences. © 1968, Human Factors and Ergonomics Society. All rights reserved.
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The theoretical basis for the Analysis of Means Technique is discussed. In addition, a simplified working procedure is outlined, step-by-step for an actual problem. The data for the problem are analyzed by the analysis of means techniques, which compares differences between means instead of population variances estimates. The data are also analyzed by the analysis of variance technique. The conclusions reached by both techniques are the same. The graphical representation of the ANOM is helpful in understanding data. The ANOM technique is usually used in conjunction with the analysis of variance, either as an initial analysis of data or to augment the analysis of variance. © Taylor & Francis Group, LLC.
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What would appear to be the simplest of the sulphur-containing pyridine ligands, 2-mercaptopyridine, gives complex, poorly-characterized derivatives with transition metal ions [1, 2]. The conversion of this compound to 2-sulfenamidopyridine and the latter's coordination to divalent metal ions yields complexes in which, in every reported instance, bonding is through the two nitrogen atoms [3]. The Schiff base derivatives of 2-sulphenamidopyridine also give species which conform to the expected mode of complexation[3]. The complexes of 2,6-dimercaptopyridine have also been reported[4]. As with the monosubstituted derivatives, no clearly defined structure has been reported, although these complexes are thought to be highly polymeric species. In this communication, the synthesis and pattern of complexation of 2,6-disulphenamidopyridine and its Schiff-base derivative with 2-pyridinaldehyde are investigated. Particular emphasis is placed on the structures of the nickel(II) analogs. © 1968.