Nickel(II)-, cobalt(II)-, copper(II)-, and zinc(II)-phthalate and 1-methylimidazole coordination compounds: synthesis, crystal structures and magnetic properties

Three new coordination polymers [M(Pht)(1-MeIm)2]n (where M=Cu (1), Zn (2), Co (3); Pht2−=dianion of o-phthalic acid; 1-MeIm=1-methylimidazole) and two compounds [M(1-MeIm)6](HPht)2 · 2H2O (M=Co (4), Ni (5)) have been synthesized and characterized by X-ray crystallography. The structures of 1–3 (2 is isostructural to 3) consist of [M(1-MeIm)2] building units connected by 1,6-bridging phthalate ions to form infinite chains. In complex 1, each copper(II) center adopts a square coordination mode of N2O2 type by two O atoms from different phthalate ions and two N atoms of 1-MeIm, whereas in 3 two independent metal atoms are tetrahedrally (N2O2) coordinated to a pair of Pht ligands and a pair of 1-MeIm molecules. There are only van der Waals interactions between the chains in 1, while the three-dimensional network in 3 is assembled by C–H⋯O contacts. In contrast to polymers 1–3 the structures of 4 and 5 (complexes are also isostructural) are made up of the [M(1-MeIm)6]2+ cation, two hydrogen phthalate anions (HPht−) and two H2O solvate molecules. The coordination around each metal(II) atom is octahedral with six nitrogen atoms of 1-MeIm. Extended hydrogen bonding networks embracing the solvate water molecules and a phthalate residue as well as the weak C–H⋯O interactions stabilize the three-dimensional structures. Magnetic studies clearly show that the magnetic ions do not interact with each other. Furthermore, in compound 4 we have another example of a highly anisotropic Co2+ ion with a rhombic g-tensor and large zero-field-splitting. The complexes were also characterized by IR and 1H NMR spectroscopy, thermogravimetric analysis, and all data are discussed in the terms of known structures.

The influence of the sample introduction system on signals of different tin compounds in inductively coupled plasma-based techniques

The influence of the sample introduction system on the signals obtained with different tin compounds in inductively coupled plasma (ICP) based techniques, i.e., ICP atomic emission spectrometry (ICP–AES) and ICP mass spectrometry (ICP–MS) has been studied. Signals for test solutions prepared from four different tin compounds (i.e., tin tetrachloride, monobutyltin, dibutyltin and di-tert-butyltin) in different solvents (methanol 0.8% (w/w), i-propanol 0.8% (w/w) and various acid matrices) have been measured by ICP–AES and ICP–MS. The results demonstrate a noticeable influence of the volatility of the tin compounds on their signals measured with both techniques. Thus, in agreement with the compound volatility, the highest signals are obtained for tin tetrachloride followed by di-tert-butyltin/monobutyltin and dibutyltin. The sample introduction system exerts an important effect on the amount of solution loading the plasma and, hence, on the relative signals afforded by the tin compounds in ICP–based techniques. Thus, when working with a pneumatic concentric nebulizer, the use of spray chambers affording high solvent transport efficiency to the plasma (such as cyclonic and single pass) or high spray chamber temperatures is recommended to minimize the influence of the tin chemical compound. Nevertheless, even when using the conventional pneumatic nebulizer coupled to the best spray chamber design (i.e., a single pass spray chamber), signals obtained for di-tert-butyltin/monobutyltin and dibutyltin are still around 10% and 30% lower than the corresponding signal for tin tetrachloride, respectively. When operating with a pneumatic microconcentric nebulizer coupled to a 50 °C-thermostated cinnabar spray chamber, all studied organotin compounds provided similar emission signals although about 60% lower than those obtained for tin tetrachloride. The use of an ultrasonic nebulizer coupled to a desolvation device provides the largest differences in the emission signals, among all tested systems.

The American vegetable practice, or, A new and improved guide to health. : Designed for the use of families. : In six parts. Part I. Concise view of the human body, with engraved and wood-cut illustrations. Part II. Glance at the old school practice of physic. Part III. Vegetable materia medica, with colored illustrations. Part IV. Compounds. Part V. Practice of medicine, based upon what are deemed correct physiological and pathological principles. Part VI. Guide for women, containing a simplified treatise on childbirth, with a description of the diseases peculiar to females and infants. /

Errata and advertisement for "New England Depot. D.L. Hale" at end of v. 2.

Federal Trade Commission vs. United States Steel Corporation, American Bridge Company, American Sheet & Tin Plate Company, Carnegie Steel Company, American Steel & Wire Company, Illinois Steel Company, Minnesota Steel Company, Tennessee Coal, Iron and Railroad Compay [sic], et al., respondents. State of Illinois, state of Iowa, state of Minnesota and state of Wisconsin, amici curiæ. Statement of case, [vol. I-II]. H.G. Pickering, attorney for amici curiæ. ... K.E. Steinhauer, attorney for Commission. Cordenio A. Severance and William W. Corlett, attorneys for the respondents.

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Tunneling, explosive compounds, and rock drills. Giving the details of practical tunnel work; the constituents and properties of modern explosive compounds; the principles of blasting; the history of ... machine rock-drilling; and detailed descriptions of the various rock-drills and air-compressors in use ... with a history of tunneling from the reign of Rameses II. to the present time.

Plates I and II on one sheet.

Tunneling, explosive compounds, and rock drills. Also, descriptions of the European and American systems, with tables giving the dimensions, cost, and leading data relating to the construction of about two thousand tunnels, compiled from notes furnished by engineers and railroad companies in North and South America, Europe, India, Australia and New Zealand, comprising a review of tunneling from the reign of Rameses II to the present time.

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The use of organotellurium heterocycles as precursors for novel organometallic compounds

The reactions of group 16 heterocycles with organometallic reagents are described. Thiophenes have been used as models for organic sulfur in coal and their reactivity towards triiron dodecacarbonyl has been investigated. Reaction of unsubstituted thiophene with Fe3(CO)12 results in desulfurisation of the heterocycle, with the organic fragment being recovered in the form of the ferrole, C4H4.Fe2(CO)6. In addition a novel organometallic compound of iron is isolated, the formula of which is shown to be C4H4.Fe3(CO)8. Bezothiophene reacts with Fe3(CO)12 to yield benzothiaferrole, C8H6S.Fe2(CO)6, in which the sulfur is retained in the heterocycle. Dibenzothiophene, a more accurate model for organic sulfur in coal, displays no reactivity towards the iron carbonyl, suggesting that the more condensed systems will desulfurise less readily. Microwave methodology has been successful in accelerating the reactions of thiophenes with Fe3(CO)12. However, reaction of benzothiophene does not proceed to the desulfurisation stage while dibenzothiophene is unreactive even under microwave conditions. Tellurophenes (Te analogues of thiophenes) are shown to mimic the behaviour of thiophenes towards certain organometallic reagents with the advantage that their greater reactivity enables recovery of products in higher yields. Hence, reaction of tellurophene with Fe3(CO)12 again affords the ferrole but with an almost ten-fold increase in yield over thiophene. More significantly, dibenzotellurophene is also detellurated by the iron carbonyl affording the previously inaccessible dibenzoferrole, C12H8.Fe2(CO)6, thereby demonstrating the mechanistic feasibility of dechalcogenation of the more condensed aromatic molecules. The potential of tellurium heterocycles to act as precursors for novel organometallics is also recognised owing to the relatively facile elimination of the heteroatom from these systems. Thus, 2-telluraindane reacts with Fe3(CO)12 to yield a novel organometallic compound of formula C16H16.Fe(CO)3, arising from the unsymmetric dimerisation of two organic fragments.

Special classes of iron(II) azole spin-crossover compounds

In this chapter, selected results obtained so far on Fe(II) spin crossover compounds of 1,2,4-triazole, isoxazole and tetrazole derivatives are summarized and analysed. These materials include the only compounds known to have Fe(II)N6 spin crossover chromophores consisting of six chemically identical heterocyclic ligands. Particular attention is paid to the coordination modes for substituted 1,2,4-triazole derivatives towards Fe(II) resulting in polynuclear and mononuclear compounds exhibiting Fe(II) spin transitions. Furthermore, the physical properties of mononuclear Fe(II) isoxazole and 1-alkyl-tetrazole compounds are discussed in relation to their structures. It will also be shown that the use of α,β- and α,ω-bis(tetrazol-1-yl)alkane type ligands allowed a novel strategy towards obtaining polynuclear Fe(II) spin crossover materials.

Experimentação em química de compostos organometálicos: preparação do cloreto de dicarbonilciclopentadienilferro(II)

In this work, we describe a new method for obtaining [Fe(CO)2[(eta5-C5H5)Cl] employing simple techniques and low-cost reagents. It is worth mentioning that this method is faster than others reported in the literature. It was applied in laboratory classes for undergraduate students, exploring different concepts in organometallic chemistry and discussing the steps involved in the synthetic route.