1,721,448 research outputs found
9.24 - The Nomenclature of Coordination Compounds - A Necessary Evil and a Pleasant Journey
No full textAs with T.S. EliotâEurotms cats, the naming of coordination compounds is a difficult matter. There is an equilibrium to be reached between usability and precision. This article discusses the need for nomenclature and presents a brief history of chemical nomenclature. The role of the International Union of Pure and Applied Chemistry (IUPAC) is identified and a short overview of the rules of inorganic nomenclature is given. The use of additive nomenclature for the construction of names of coordination compounds is described and methods for the description of the bonding of complicated ligands are introduced. The final section looks towards the future development of nomenclature schemes designed for machine rather than human readability
Celebrating the 100th Anniversary of the Nobel Prize in Chemistry awarded to Alfred Werner
No full textA Short History of Coordination Compounds: The Journey From Plant Extracts to the Present Day
No full textCoordination chemistry had its origins as a practical technology in prehistory. In the intervening millennia, it has developed into a precise molecular science. This article describes some of the milestones in the evolution of coordination chemistry, with an emphasis on the historical development of physical methods
Half a grid is better than no grid : competition between 2,2':6',2"-terpyridine and 3,6-di(pyrid-2-yl)pyridazine for copper(II)
No full textThe reaction between Cu(NO3)2·3H2O, 2,2′:6′,2′′-terpyridine (tpy) and 3,6-di(pyrid-2-yl)pyridazine (1) in a 2 : 2 : 1 molar equivalent ratio in aqueous MeCN in the presence of excess NH4PF6 leads to competition between the assembly of the dinuclear half-grid [Cu2(1)(tpy)2][PF6]4·2H2O and the mononuclear complex [Cu(1)2(OH2)][PF6]2. The yield of [Cu2(1)(tpy)2][PF6]4·2H2O has been optimized using microwave conditions. [Cu(1)2(OH2)][PF6]2 can be selectively produced by treating Cu(NO3)2·3H2O with 1 (1 : 2 molar equivalents) in aqueous MeCN in the presence of NH4PF6. The single crystal structures of [Cu2(1)(tpy)2][PF6]4·4MeNO2 and [Cu(1)2(OH2)][PF6]2 are presented. In the [Cu2(1)(tpy)2]4+ cation, ligand 1 bridges the two copper(II) centres, each of which is further coordinated by a tpy ligand. The copper(II) coordination geometry is closely associated with the arrangement of the two tpy ligands which engage in efficient face-to-face π-stacking. Magnetic data for crystalline [Cu2(1)(tpy)2][PF6]4·4MeNO2 are consistent with a weak antiferromagnetic interaction between the two copper(II) centres. EPR spectroscopic data for a powder sample of [Cu2(1)(tpy)2][PF6]4·2H2O are consistent with the dinuclear structure, but in frozen DMF and DMSO solutions, the data indicate that the dinuclear structure of [Cu2(1)(tpy)2]4+ is not preserved
Homoleptic metal complexes of 4'-(5-pyrimidinyl)-2,2':6',2''-terpyridine : tetrafurcated expanded ligands
No full textWith iron(II) and ruthenium(II), 4`-(5-pyrimidinyl)-2,2`: 6`,2 ``-terpyridine (L) preferentially coordinates through the tpy domain to give octahedral [ML2](2+) (M Fe, Ru) complexes. Treatment of [RuL2][PF6](2) with CuCl2 center dot 2H(2)O leads to [Ru(2)(2)][CuCl2(OH2)][CuCl3]Cl center dot 3MeCN center dot 7H(2)O(n) which exhibits a two-dimensional coordination network with copper(II) centres interconnecting [RuL2](2+) motifs. Magnetic susceptibility data for the material are consistent with a one-dimensional S = 1/2 antiferromagnetic chain
Structural diversity in the reactions of 4 '-(pyridyl)-2,2 ':6 ',2 ''-terpyridine ligands and bis{4 '-(4-pyridyl)-2,2 ':6 ',2 ''-terpyridine}iron(II) with copper(II) salts
No full textWe have demonstrated that treatment of [Fe(1)(2)](2+) (1 = 4'-(4-pyridyl)-2,2':6',2 ''-terpyridine) with an excess of CuCl2 center dot 2H(2)O leads to competition between coordination of copper(II) by the pendant pyridine donors in [Fe(1)(2)](2+), and transfer of ligand 1 from iron(II) to copper(II) to yield [{Cl3Cu(mu-1)Fe(mu-1)}(2)CuCl2(OH2)(2)]Cl-2 center dot 4H(2)O and [Cu(H1)Cl-2]Cl center dot 4H(2)O, respectively. Direct reaction of 1 with CuCl2 center dot 2H(2)O and variation in crystallization conditions results in the formation of either monomeric or polymeric complexes: [Cu(1)Cl-2]center dot 4.75H(2)O, [Cu(1)Cl-2]center dot H2O center dot MeOH and [Cu(1)Cl-2 center dot 2H(2)O](n). The reaction of 1 with Cu(NO3)(2)center dot 3H(2)O gives the coordination polymer [Cu(1)(ONO2)(2)center dot H2O](n). Magnetic data for [Cu(1)Cl-2 center dot 2H(2)O](n) and [Cu(1)(ONO2)(2)center dot H2O](n) are consistent with antiferromagnetically- coupled chains. Reactions of CuCl2 center dot 2H(2)O with ligands 2 and 3 (2 = 4'-(3-pyridyl)-2,2':6',2 ''-terpyridine, 3 = 4'-(2-pyridyl)-2,2':6',2 ''-terpyridine) lead to monomeric complexes. With the exception of [Cu(3)Cl-2], the mononuclear complexes show a propensity for the incorporation of water into their crystal lattices; in the case of [Cu(H1)Cl-2]Cl center dot 4H(2)O and [Cu(H1)Cl-2]Cl center dot 4.75H(2)O, the small change in water content leads to the assembly of (5.8(2))(2)(5.6.8)(4)(5(2).6)(2) or (4(2).6(2))(3)(4.6(2))(6) water-chloride ion nets
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Preparation and photophysical studies of copper(I) and ruthenium(II) complexes of 4,4′-bis(3,5-dimethoxyphenyl)-6,6′-dimethyl-2,2′-bipyridine
No full textWe report the synthesis of a new ligand, 4,4'-bis(3,5-dimethoxyphenyl)-6,6'-dimethyl-2,2'-bipyridine, optimised for binding to copper(I) and with pendant functionality that can eventually be developed into metallodendritic structures. The synthesis and photophysical properties of complexes with copper(I) and ruthenium(II) are reported. The solid state structure of the complex [Cu(1)(2)][PF6] center dot MeCN (1 = 4,4'-bis(3,5-dimethoxyphenyl)- 6,6'-dimethyl-2,2'-bipyridine) is also described. (C) 2008 Elsevier B. V. All rights reserved
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