Tetraamine Complexes Research Articles

Electron paramagnetic resonance study of the role of CuO additives in altering phase transition behavior of ammonium nitrate

The role of CuO in reducing the volume change and altering the transition temperature of structural phase transitions in ammonium nitrate is studied by electron paramagnetic resonance (EPR). At room temperature, two distinct EPR spectra, indicative of two chemical forms of copper were observed in ammonium nitrate heated from the melt containing 5% by weight of CuO and through which NH3 gas was bubbled. One spectrum having an orthorhombic g tensor with principle components g1 = 2.185, g2 = 2.109, and g3 = 2.055 is assigned to the Cu(NH3)2+4 complex. The other spectrum, also having orthorhombic symmetry, with g1 = 2.315, and g2 = 2.264, is tentatively assigned to a Cu2+ ion either interstitial or substitutional in the lattice. The g values of this spectrum were quite sensitive to temperature and change substantially during the structural phase transition at 60 °C. Heating ammonium nitrate to 160 °C for an hour changed the tetramine copper complex into a new spectrum which is identified as the diamine complex of copper. At room temperature this spectrum slowly returned to the tetramine complex. The role of these forms of copper in reducing the volume change associated with the above room-temperature phase transition is discussed.

The electrochemistry of square planar macrocyclic nickel complexes and the reaction of Ni(I) with alkyl bromides: Nickel tetraamine complexes

The electrochemistry of nine cyclic tetraamine complexes of Ni(II) in aprotic solvents has been investigated. It is shown that all form Ni(I) complexes which react with alkyl bromides, but only with some complexes are the reactions catalytic with respect to the nickel complex. The dependence of the electrochemical parameters and the mechanism and kinetics of the coupled chemical reactions on the structure of the ligands are discussed.

The electrochemistry of square planar macrocyclic nickel complexes and the reaction of Ni(I) with alkyl bromides: nickel tetraamine complexes

The electrochemistry of square planar macrocyclic nickel complexes and the reaction of Ni(I) with alkyl bromides: nickel tetraamine complexes

Application of the Edwards equation to formation of adducts of Cu(II) open-chain tetraamine complexes with anions

Application of the Edwards equation to formation of adducts of Cu(II) open-chain tetraamine complexes with anions

Application of the Edwards equation to formation of adducts of copper(II) macrocyclic tetraamine complexes with anions

Application of the Edwards equation to formation of adducts of copper(II) macrocyclic tetraamine complexes with anions

Reaction of cobalt(II) macrocyclic tetra-amine complexes with dioxygen

Low-pH equilibrium and kinetic studies on the oxygenation of [CoL]2+ complexes containing 12–(L2), 13–(L3), and 14-membered (isomeric, L4 and L5) fully saturated macrocyclic tetra-amines are reported. The ring size strongly influences the stability of the oxygenated products. The relative stability is connected with the stoicheiometry of the oxygenated complex, [(CoL)2(O2)(OH)]3+ for L2 and L3 and [(CoL)2(O2)]4+ for L5, which has been elucidated by potentiometric titration and polarographic measurements. The results for the macrocyclic systems are compared with a linear tetra-amine system (L1). The cyclic nature of the macrocycles, while serving to raise the [CoL]2+ stability, markedly lowers the O2 affinity of the complexes. Rates for the reaction of Co2+, L, and O2 in acetate buffers (yielding the dioxygen adducts) are first order in [Co2+] and also in [L], but are independent of [O2], indicating that the formation of [CoL]2+ is the slowest step in the O2 uptake. The separate reaction of [CoL]2+ with O2 is first order in [CoL2+] and also in [O2], with the second-order rate constants being ca. 104 times faster than those for the formation of [CoL]2+ under comparable conditions. The presence of the macrocyclic ligand slows down (by ca. 102 times) the overall rate of O2 uptake compared with linear totra-amine systems.

Thermodynamic studies on the complexation reaction of copper(II) macrocyclic tetramine complexes with hydroxide ion

The relative stabilities of the red and blue forms of each of the complexes [CuL]2+ and [CuL(OH)]+(L =meso- or rac-5,5,7,12,12,14-hexamethyl-1,4,8,11-tetra-azacyclotetradecane) have been determined by a spectrophotometric method in basic solution at 25 °C and l= 0.1 mol dm–3. The factors which influence the relative stabilities are discussed.

The Crystal Structure of (2R, 7S, 10R)-2,10-diamino-5,5,7-trimethyl-4,8-diazaundecanenickel (II) perchlorate

The structure of the title compound, a tricyclic Ni(II) tetra-amine complex has been determined from analysis of photographic X-ray data. The crystal system is orthorhombic, space group P212121, with unit cell dimensions a = 9.802, b = 8.998, c = 24.378 Å. The Ni atom is square planar coordinated. The six-membered chelate ring has a chair conformation. One of the five-membered chelate rings has a distorted gauche (λ) conformation with the methyl substituent in an equatorial position, the other has an unsymmetrical gauche (δ) conformation with the methyl substituent axial.

Thermodynamic and kinetic effects of 13-membered macrocycles. Polarographic studies of 1,4,7,10-tetra-azacyclotridecanecopper(II)

Thermodynamics and kinetics of complex formation between Cu2+ and 1,4,7,10-tetra-azacyclotridecane(L2) in acetate-buffered solution have been studied polarographically. The stability constant (log K 29.1 at 25 °C) for the 1 : 1 complex with 5,5,5,6-membered chelate rings is ca. 105- and 109-fold greater than those for the corresponding open-chain tetra-amine complexes with 5,6,5- and 5,5,5-membered chelate rings, respectively. The enhanced stability with the 13-membered cyclic ligand is largely due to a more favourable entropy change, as found for 12-membered macrocycles. However, there is a significant, although small, contribution from the enthalpy term. These trends may link the differences between the 12- and 14-membered macrocyclic effects. The rate law (pH < 4, 25 °C) is d[(CuL2)2+]/dt=k5[Cu(O2CMe)+][(HL2)+]+k6[Cu(O2CMe)+][(H2L2)2+], where k5=(5.6 ± 0.5)× 106 dm3 mol–1s–1and k6= 10.1 ± 1 dm3 mol–1 s–1. The activation parameters for [HL2]+ reaction are ΔH‡= 16.1 kcal mol–1 and ΔS‡=+26.9 cal K–1 mol–1, and for [H2L2]2+ reaction are ΔH‡= 11.6 kcal mol–1 and ΔS‡=–15.1 cal K–1 mol–1. The strikingly different activation parameters between [HL2]+ and [H2L2]2+ reactions suggest a shift of the reaction mechanism from dissociative to associative. The kinetic behaviours indicate that the 13-membered macrocycles have intermediate properties between 12-membered cyclic and open-chain tetra-amines.

ChemInform Abstract: THERMODYNAMIC BEHAVIOUR OF COMPLEXES WITH 5,6‐MEMBERED CONDENSED CHELATE RINGS, 1,4,8‐TRIAZAOCTANE

Chemischer InformationsdienstVolume 6, Issue 9 Organoelement Compounds ChemInform Abstract: THERMODYNAMIC BEHAVIOUR OF COMPLEXES WITH 5,6-MEMBERED CONDENSED CHELATE RINGS, 1,4,8-TRIAZAOCTANE ROLANDO BARBUCCI, ROLANDO BARBUCCISearch for more papers by this authorLUIGI FABBRIZZI, LUIGI FABBRIZZISearch for more papers by this authorPIERO PAOLETTI, PIERO PAOLETTISearch for more papers by this author ROLANDO BARBUCCI, ROLANDO BARBUCCISearch for more papers by this authorLUIGI FABBRIZZI, LUIGI FABBRIZZISearch for more papers by this authorPIERO PAOLETTI, PIERO PAOLETTISearch for more papers by this author First published: March 4, 1975 https://doi.org/10.1002/chin.197509352AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume6, Issue9March 4, 1975 RelatedInformation

Diminution of the macrocyclic effect for nickel(II) complexes of thioethers in nonaqueous solvents

The ratio of stability constants for 14-membered macrocyclic vs. open-chain tetrathia complexes of NiII in nitromethane is only 180, whereas the corresponding ratio for tetramine complexes in water is 106.4, lending support to the hypothesis that (in addition to contributions from configurational entropy) the differing degree of ligand solvation by hydrogen bonding in water is a major source of the macrocyclic effect.

Ligand solvation and the macrocyclic effect. Nickel(II)-tetramine complexes

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLigand solvation and the macrocyclic effect. Nickel(II)-tetramine complexesFrederick P. Hinz and Dale W. MargerumCite this: Inorg. Chem. 1974, 13, 12, 2941–2949Publication Date (Print):December 1, 1974Publication History Published online1 May 2002Published inissue 1 December 1974https://doi.org/10.1021/ic50142a032RIGHTS & PERMISSIONSArticle Views513Altmetric-Citations127LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1 MB) Get e-Alerts Get e-Alerts

Thermodynamic behaviour of complexes with 5,6-membered condensed chelate rings: 1,4,8-triazaoctane

The enthalpies of the reactions. in 0·5M-KNO3 at 25 °C, between the linear tri-amine 1,4,8-triazaoctane (2,3-tri) and nickel(II), copper(II), and zinc(II) ions have been determined by means of direct calorimetric titrations. By using the ΔG° values reported elsewhere the corresponding ΔS° values have been calculated. The ML complexes of (2,3-tri) which contain a system of condensed chelate rings with a 5,6-ring size sequence, have heats of formation higher than those of the corresponding complexes of (2,2-tri)(5,5-ring size sequence) and of (3,3-tri)(6,6-sequence). An analogous trend has already been observed in tetra-amine complexes. The importance of steric factors in the formation of the ML2 complexes is discussed.

Linear relation between the enthalpy of formation and the frequency of the maximum in the electronic absorption spectra of the copper(II)-tetramine complexes

ADVERTISEMENT RETURN TO ISSUEPREVArticleLinear relation between the enthalpy of formation and the frequency of the maximum in the electronic absorption spectra of the copper(II)-tetramine complexesP. Paoletti, L. Fabbrizzi, and R. BarbucciCite this: Inorg. Chem. 1973, 12, 8, 1961–1962Publication Date (Print):August 1, 1973Publication History Published online1 May 2002Published inissue 1 August 1973https://doi.org/10.1021/ic50126a064RIGHTS & PERMISSIONSArticle Views145Altmetric-Citations19LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (287 KB) Get e-Alerts Get e-Alerts

Isomeric macrocyclic tetramine complexes of cobalt(III). Some problems of stereochemistry and chemical reactivity

Cis-trans and ligand configurational equilibria have been investigated in several Co III(N 4)X 2 complexes, where (N 4) designates a Curtis-type macrocyclic tetraamine ligand. Ligand configurational isomers are assumed to result from changes in the configuration of atoms around asymmetric coordinated nitrogen atoms. Several new isomers have been detected and tentatively assigned structures. Interconversion between isomers has been found to be relatively rapid in dilute acid. Several ligand configurations of trans-Co(N 4)(OH 2) 2 3+ appear to have about the same energy as the most stable cis-diaquo isomer, whereas cis-Co(N 4)Cl 2 + has been shown to be far less stable than trans-Co(N 4)Cl 2 +.

Chemical Effects of the (n,y) Reactions in Dichlorotriethylene Tetramine Complexes of Cobalt (111) and Rhodium(lll)

Article Chemical Effects of the (n,y) Reactions in Dichlorotriethylene Tetramine Complexes of Cobalt (111) and Rhodium(lll) was published on July 1, 1970 in the journal Radiochimica Acta (volume 14, issue 1).

Macrocyclic effect on the stability of copper(II) tetramine complexes

Macrocyclic effect on the stability of copper(II) tetramine complexes

A Comparative Study of Quinoline and Hexamethylene Tetramine Complexes with Ethereal Blue Perchromate in Relation to the Constitution of Blue and Red Perchromates

A Comparative Study of Quinoline and Hexamethylene Tetramine Complexes with Ethereal Blue Perchromate in Relation to the Constitution of Blue and Red Perchromates

Far infrared spectra of palladium compounds—III Tetrahalo, tetraammine and dihalodiammine complexes] of palladium (II)

The infrared spectra of a number of square planar palladium (II) complexes of the type M 2PdX 4, PdL 4X 2, and trans and cis isomers of PdL 2X 2 (where M = NH 4 +, K +, Rb +, or Cs +; L = NH 3; X = Cl −, Br −, or I −) have been recorded from 4000 to 40 cm −1. The compounds were examined both at room temperature and at liquid nitrogen temperature. The investigation of four tetrachloropalladium (II) complexes gave Pdz.snfc; stretching vibrations in the range 327–336 cm −1, Pdz.snfc; in-plane bending vibrations in the range 183–205, and Pdz.snfc; out-of-plane bending vibrations from 160 to 175 cm −1. Four similar bromo complexes gave the corresponding PdBr vibrations in the ranges 249–260 cm −1, 130–169 cm −1 and 114–140 cm −1, respectively. The PdN in and out-of-plane bending vibrations of the tetraamine complexes were found in the ranges 245–273 and 160–190 cm −1, respectively. By using the assignments for the tetrahalo and tetraammine complexes as well as isotopic shift data, assignments for the fundamental modes for a series of cis and trans dihalodiammine complexes of palladium (II) are given and discussed.

Some copper(II) and nickel(II) amine-cyanide derivatives. I. Solution equilibria

Addition of cyanide to aqueous solutions of some copper(II) and nickel(II) tetramine complexes causes an immediate colour change, from mauve to blue for the copper compounds and orange to pink for the nickel compounds, these colours then slowly fading to colourless [Cu(CN)4]3- and pale yellow [Ni(CN)4]2- respectively as the amine complexes decompose. Spectrophotometric studies on the solutions indicate that the immediate colour change is caused by the formation of a monocyanide adduct, the formation constant being of the order of 102 for the copper(II) compounds and 10 for the nickel(II) compound studied. Measurements of the absorption spectrum and magnetic susceptibility show that the nickel(II) cyanide adduct has a triplet ground state.