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Fairbank MG, Norman PR, McAuley A. Steric effects on the rates of redox reactions involving nickel(II/III) macrocycles. Inorg Chem 2002. [DOI: 10.1021/ic00211a011] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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McAuley A, Xu C. Chemical oxidation of the ligand in nickel(II) cyclam: formation of a novel dinuclear complex and of a related cation containing a ligand radical ion. Inorg Chem 2002. [DOI: 10.1021/ic00052a034] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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McAuley A, Whitcombe TW, Zaworotko MJ. Crystal and solution structure of two dinuclear hexadentate macrocyclic complexes of palladium(II). Inorg Chem 2002. [DOI: 10.1021/ic00018a023] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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McAuley A, Morton JR, Preston KF. Single-crystal EPR spectra of two nickel(III) tetraazamacrocycle complexes. J Am Chem Soc 2002. [DOI: 10.1021/ja00390a028] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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McAuley A, Olubuyide O, Spencer L, West PR. Kinetics and mechanism of reduction of nickel(III) complexes by titanium(III) in aqueous media. Inorg Chem 2002. [DOI: 10.1021/ic00185a011] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Chandrasekhar S, McAuley A. Evidence for ligand isomerism in the palladium(II) complex of 1,4,7-trithiacyclodecane. Inorg Chem 2002. [DOI: 10.1021/ic00038a067] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Macartney DH, McAuley A. Kinetics of formation of (thiourea)pentacyanoferrate(II) complexes in aqueous perchlorate media. Inorg Chem 2002. [DOI: 10.1021/ic50217a022] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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McAuley A, Xu C. Kinetics and mechanism of electron-transfer reactions of bis((-)-(R)-2-methyl-1,4,7-triazacyclononane)nickel(II) and -nickel(III) complexes. Inorg Chem 2002. [DOI: 10.1021/ic00280a022] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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McAuley A, Norman PR, Olubuyide O. Preparation, characterization, and outer-sphere electron-transfer reactions of nickel complexes of 1,4,7-triazacyclononane. Inorg Chem 2002. [DOI: 10.1021/ic00181a029] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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McAuley A, Subramanian S. Structure and reactivity of the nickel(II) complex of a new open-chain amine 6,6-bis(4-amino-2-azabutyl)-1,4-diazacycloheptane and of the nickel(III) complex of its macrocyclic analog: effects on the reduction of perchlorate ion. Inorg Chem 2002. [DOI: 10.1021/ic00003a005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Rodopoulos M, Rodopoulos T, Bridson JN, Elding LI, Rettig SJ, McAuley A. Synthesis of 14-oxa-1,4,8,11-tetraazabicyclo[9.5.3]nonadecane (L1) and a Spectroscopic and Structural Study of [Ni(L1)(ClO4)](ClO4) and of the Macrobicyclic Precursor Diamide Complex, [Ni(HL2)](ClO4); Chloride Substitution Kinetics of the Corresponding [Ni(III)(L1)]3+ Species. Inorg Chem 2001; 40:2737-42. [PMID: 11375689 DOI: 10.1021/ic001163r] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The pentadentate ligand 14-oxa-1,4,8,11-tetraazabicyclo[9.5.3]nonadecane (L1) has been synthesized by the high dilution cyclization of 1-oxa-4,8-diazacyclododecane ([10]aneN(2)O) (1) with 1,3-bis(alpha-chloroacetamido)propane (2) and subsequent reduction of the diamide intermediate. The structure [Ni(L1)(ClO(4))](ClO(4)) (P2(1)/c (no. 14), a = 8.608(3), b = 16.618(3), c = 14.924(4) A, beta = 91.53(3) degrees converged at R = 0.050 (R(w) = 0.046) for 307 parameters using 2702 reflections with I > 2sigma(I). For the nickel(II) complex of the (monodeprotonated) precursor diamide ligand 14-oxa-1,4,8,11-tetraazabicyclo[9.5.3]nonadecane-3,9-dione (H(2)L2), [Ni(HL2)](ClO(4)) (Pbca (no. 61), a = 15.1590(3), b = 13.235(2), c = 18.0195(6) A), the structure converged at R = 0.045 (R(w) = 0.038) for 265 parameters using 1703 reflections with I > 3sigma(I). In the reduced system, the cyclam-based ligand adopts a trans-III configuration. The [Ni(L1)(ClO(4))](2+) ion is pseudooctahedral with the Ni-O(ether) 2.094(3) A distance shorter than the Ni-O(perchlorate) 2.252(4) A. The nickel(II) and nickel(III) complexes are six-coordinate in solution. Oxidation of [Ni(L1)(OH(2))](2+) with K(2)S(2)O(8) in aqueous media yielded an axial d(7) Ni(III) species (g( perpendicular) = 2.159 and g( perpendicular) = 2.024 at 77 K). The [Ni(L1)(solv)](2+) ion in CH(3)CN showed two redox waves, Ni(II/I) (an irreversible cathodic peak, E(p,c) = -1.53 V) and Ni(III/II) (E(1/2) = 0.85 V (reversible)) vs Ag/Ag(+). The complex [Ni(HL2)](ClO(4)) displays square-planar geometry with monodeprotonation of the ligand. The ether oxygen is not coordinated. Ni-O(3) = 2.651(6) A and Ni-O(3a) = 2.451(12) A, respectively. The Ni(III/II) oxidation at E(1/2) = 0.24 V (quasi-reversible) vs Ag/Ag(+) is considerably lower than the saturated system. The kinetics of Cl(-) substitution at [Ni(L1)(solv)](3+) are pH dependent. Detachment of the ether oxygen atom is proposed, with insertion of a protonated water molecule which deprotonates at a pK(a) more acidic than in the corresponding cyclam complex. Mechanistic implications are discussed.
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Bush J, McAuley A, Pecaitis F. Navigating the options. HEALTH MANAGEMENT TECHNOLOGY 2000; 21:22, 24-5. [PMID: 11155627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
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McAuley A, Subramanian S. Synthesis and characterization of Ni(II) and Cu(II) complexes of 6-(β-(3,4-dimethoxyphenylethyl))cyclam (L1) and 6-(β-(3,4-dihydroxyphenylethyl))cyclam (H2L2) (cyclam=1,4,8,11-tetraazacyclotetradecane). X-ray crystal structures of [Cu(L1)Br2] and [Cu(H2(BrL2))Br]Br·H2O and metal ion templated formation of multinuclear macrocyclic complexes. Inorganica Chim Acta 2000. [DOI: 10.1016/s0020-1693(99)00554-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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McAuley A, Subramanian S, Zaworotko MJ, Biradha K. Stepwise Complexation of Ni(II) and Cu(II) Ions by 6,6'-C-spirobi(cyclam) (cyclam = 1,4,8,11-Tetraazacyclotetradecane), L(1). Syntheses and Redox Chemistry of [M(H(2)L(1))]X(4) (M = Cu(2+), Ni(2+)), [Cu(2)(L(1))]X(4), and [CuNi(L(1))]X(4) (X = ClO(4)(-)) and the X-ray Crystal Structure of [Cu(2)(L(1))](ClO(4))(4). Inorg Chem 1999; 38:5078-5085. [PMID: 11671254 DOI: 10.1021/ic9904844] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In aqueous HClO(4), the cation [H(4)(L(1))](4+) where L(1) is 6,6'-C-spirobi(cyclam) (cyclam = 1,4,8,11-tetraazacyclotetradecane), complexes Cu(2+) and Ni(2+) ions in a stepwise fashion to form [M(H(2)L(1))](ClO(4))(4) (M = Cu(2+) and Ni(2+)) from which [CuNi(L(1))](ClO(4))(4) has been prepared selectively. The preparation and the structure of [Cu(2)(L(1))](ClO(4))(4) (empirical formula, C(19)H(44)N(8)Cu(2)Cl(4)O(16); space group, triclinic; P&onemacr;; a = 8.1815(6) Å, b = 12.6098(9) Å, c = 16.6565(12) Å, alpha = 80.3890(10) degrees, beta = 76.5840(10) degrees, gamma = 87.1750(10) degrees, V = 1647.9(2) Å(3), and Z = 2; of the 9531 total reflections collected, 6779 reflections with I > 2sigma(I) on least-squares refinement provided final R(1) = 0.0657 and wR(2) = 0.1424) are also reported. The cyclic voltammograms (1.0 M NaCl, 0.1 M H(+); Pt electrodes; all E(1/2) vs NHE) of [M(H(2)L(1))](4+) (M = Cu(2+) and Ni(2+)) ions show single waves for the Cu(II)/Cu(III) couple (E(1/2) = 0.79 V, irreversible) and the Ni(II)/Ni(III) couple (E(1/2) = 0.56 V, reversible), respectively. In CH(3)CN (0.1 M Et(4)NClO(4)), the [Cu(2)(L(1))](4+) ion shows a reversible wave for the Cu(II)-Cu(II)/Cu(II)-Cu(III) couple ((1)E(1/2) = 1.120 V) and an irreversible wave for the Cu(II)-Cu(III)/Cu(III)-Cu(III) couple ((2)E(1/2) = 1.430 V). Similarly, a reversible wave for the Cu(II)-Ni(II)/Cu(II) -Ni(III) couple ((1)E(1/2) = 0.750 V) and an irreversible wave for the Ni(III)-Cu(II)/Ni(III)-Cu(III) couple ((2)E(1/2) = 1.20 V) are observed in the case of the [Cu(II)Ni(II)(L(1))](4+) ion. The [Cu(2)(L(1))](4+) ion (g( perpendicular) = 2.120, g( parallel) = 2.256 and 2.196, A( parallel) = 150 G, and D( parallel) = 75 G) and the mixed valent species [Cu(II)Ni(III)(L(1))](5+) (for Cu(2+), g( perpendicular) = 2.060, g( parallel) = 2.219, and A( parallel) = 100 G; for Ni(3+) in sulfate media, g( perpendicular) = 2.204 and g( parallel) = 1.967) and [Cu(II)Cu(III)(L(1))](5+) (g(xx)() = 1.982, g(yy)() = 2.155, g(zz)() = 2.386, A(yy)() = 80 G, and A(zz)() = 120 G) show dipolar-dipolar interaction. In the mixed-valent ions, due to strong electrostatic repulsion from either the Ni(III) or Cu(III) ions, significantly smaller A( parallel) (or A(zz)()) values are observed for the Cu(2+) ion compared to 200 G in the mononuclear ions. Also, the [Cu(II)Ni(II)(L(1))](4+) in aqueous HClO(4) and the [Ni(2)(L(1))](4+) ion in CH(3)NO(2) show a tendency to reduce perchlorate very slowly.
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Mackay I, Cai LZ, Kirk AD, McAuley A. Quenching of Triplet State Tetrakis(&mgr;-pyrophosphito-PP')diplatinate(II) by Nickel(II) Macrocyclic and Tris-diimine Complexes. Inorg Chem 1999; 38:3628-3633. [PMID: 11671118 DOI: 10.1021/ic990093p] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The excited state of tetrakis(&mgr;-pyrophosphito-PP')diplatinate(II), Pt(2)(pop)(4)(4)(-), has been shown to be reductively quenched by a series of Ni(II) complexes. Steady-state photolysis of Pt(2)(pop)(4)(4)(-) in the presence of Ni(cyclam)(2+) and SO(4)(2)(-) ions was followed by absorption spectroscopy and showed the production of the Ni(III) complex with low efficiency. The Ni(III) yield was enhanced in the presence of oxygen presumably because of scavenging of Pt(2)(pop)(4)(5)(-) from the solvent-caged {Pt(2)(II,I).Ni(III)} primary product pair resulting from electron transfer. Cage escape yields of 0.028 in N(2) saturated solution and 0.054 in aerated solutions were estimated from the data. For a series of complexes with decreasing redox potential, the rate constants for their (3)Pt(2)(pop)(4)(4)(-) phosphorescence lifetime quenching decreased with driving force DeltaG, consistent with Rehm-Weller behavior and leading to a reorganization energy of approximately 60 kJ mol(-)(1). The diffusional rate constant calculated from the Debye-Smoluchowski equation was 1.6 x 10(10) M(-)(1) s(-)(1), in excellent agreement with the observed value of 1.6 x 10(10) M(-)(1) s(-)(1) based on the Rehm-Weller equation. The transmission factor for the electron transfer was estimated at 10(-)(4), in the weakly adiabatic region. Although the Rehm-Weller treatment has been used successfully in reactions involving mainly uncharged organic reactants, in this investigation it leads to an unrealistic ratio for the rate constants for the diffusive separation of the charged reactants and products. An alternative interpretation of the results based on an approach by Meyer and Nagle removes this problem and the observed linear dependence of ln k(q) on the square root of E degrees (Ni(II)/Ni(III)) in the endergonic region shows that the dominant back electron transfer produces ground-state species. The analysis also leads to an estimate of the (3)Pt(2)(pop)(4)(4)(-)/Pt(2)(pop)(4)(5)(-) potential of 1.29 +/- 0.05 V(vs NHE), in excellent agreement with the previous literature value of 1.34 V.
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McAuley A, Subramanian S, Zaworotko MJ, Atencio R. A Novel Mixed Macrocycle Complex of Nickel: Synthesis, Structure, and Redox Chemistry of [Ni(II)([9]aneN(3))([9]aneS(3))](ClO(4))(2).CHCl(3) ([9]aneN(3) = 1,4,7-Triazacyclononane and [9]aneS(3) = 1,4,7-Trithiacyclononane). Inorg Chem 1998; 37:4607-4610. [PMID: 11670608 DOI: 10.1021/ic980099z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The mixed macrocycle cation, [Ni([9]aneN(3))([9]aneS(3))](2+) (where [9]aneN(3) = 1,4,7-triazacyclononane and [9]aneS(3) = 1,4,7-trithiacyclononane), has been prepared by stepwise complexation of [9]aneN(3) and [9]aneS(3), respectively, to Ni(II) cation. The intermediate [Ni([9]aneN(3))(CH(3)NO(2))(3)](2+) has been isolated and characterized by mass spectrometry and UV-visible spectroscopy. Cyclic voltammetry of [Ni([9]aneN(3))(CH(3)NO(2))(3)](2+) shows a quasireversible wave for the Ni(II/III) couple (E(1/2) = 0.73V vs Fc(+/0)), and the Ni(III) species exhibits an axial ESR spectrum (g( perpendicular) = 2.101 and g( parallel) = 1.985). The structure of [Ni([9]aneN(3))([9]aneS(3))](ClO(4))(2).CHCl(3) has been determined. It crystallizes in monoclinic space group P2(1)/c with a = 13.3911(8) Å, b = 14.4430(9) Å, c = 13.6116(8) Å, beta = 107.2090(10) degrees, V = 2514.7(3) Å(3), and Z = 4. Of the 15 047 reflections collected, 5765 reflections (I > 2sigma(I)) were used in the refinement to obtain a final R(w) = 0.0278 and R(F) = 0.0368. In the cation [Ni([9]aneN(3))([9]aneS(3))](2+), the two macrocycles occupy the trigonal faces of the Ni(2+) ion, imposing a distorted octahedral geometry. Cyclic voltammetry of the complex in CH(3)CN (Pt electrodes, 0.1 M n-Bu(4)NClO(4), 500 mV) shows a quasireversible wave for the Ni(II)/Ni(III) couple (E(1/2) = 0.86V vs Fc(+/0)). Chemical oxidation by NOPF(6) of the cation [Ni([9]aneN(3))([9]aneS(3))](2+) generates a Ni(III) species that shows axial ESR spectrum with g( perpendicular) = 2.106 and g( parallel) = 2.063. No characteristic reduction wave was observed in either CH(3)CN or CH(3)NO(2) media.
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Eisensehr I, Ehrenberg BL, Noachtar S, Korbett K, Byrne A, McAuley A, Palabrica T. Platelet activation, epinephrine, and blood pressure in obstructive sleep apnea syndrome. Neurology 1998; 51:188-95. [PMID: 9674801 DOI: 10.1212/wnl.51.1.188] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE There is an increased risk of patients with obstructive sleep apnea syndrome (OSAS) to have stroke or cardiac infarcts. Besides hypertension, epinephrine-induced platelet activation could be a further reason for the increased cardiovascular morbidity and mortality in OSAS. METHODS During a 4-month period (August 1994 to December 1994) we recruited prospectively 76 patients referred for polysomnograms because of a suspected sleep disorder such as OSAS. RESULTS Fifty patients had no respiratory events during sleep (non-OSAS), 19 patients had more than five but less than 50 obstructive apneas or hypopneas per hour of total sleep time (mild-to-moderate OSAS group), and seven patients had an apnea hypopnea index of more than 50 per hour of total sleep time (severe OSAS group). Blood pressure, plasma epinephrine levels, and P-selectin expression (as a marker for platelet activation) were measured in every patient at 9 PM and 6 AM (before and after the polysomnogram). There was a significant correlation of the apnea hypopnea index with 9 PM and 6 AM systolic and diastolic blood pressure, with 9 PM platelet activation, and with 6 AM epinephrine levels mainly due to high values in the severe OSAS group. CONCLUSIONS Our results suggest that platelet activation, epinephrine, and high blood pressure play a role in the high prevalence of cerebrovascular and cardiovascular events in patients with OSAS.
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McAuley A, Subramanian S. Synthesis, Spectroscopy, and Redox Behavior of the Binuclear Complex Cation [Ni2(6,6‘-spirobi(cyclam))]4+(cyclam = 1,4,8,11-Tetraazacyclotetradecane): Characteristics of a Transient Ni(II)−Ni(III) Species. Inorg Chem 1997. [DOI: 10.1021/ic970327+] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Chaka B, McAuley A, Whitcombe T. Novel geometries exhibited by three palladium(II) macrocyclic complexes: crystal and solution structures. Inorganica Chim Acta 1996. [DOI: 10.1016/0020-1693(96)05121-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Abstract
This study aimed to identify the prevalence of mental disorder in hostels for the homeless in Belfast, Northern Ireland. In addition, it attempted to assess the facilities and support offered from both the hostels and the Health Service to homeless people who have a mental disorder. Lastly it sought to determine whether or not psychiatric hospital bed closure had any influence on the prevalence of homelessness among these persons in Belfast. An exploratory approach was adopted, using semi-structured interviews as the method of data collection. The sample consisted of 12 hostels for the homeless with a total occupancy of 250 residents. Officers in charge were surveyed. The results obtained indicated that approximately 25% of the homeless in Belfast hostels have a diagnosed mental disorder and that hospital closure has had a direct effect on the size of this percentage. In addition, it was found that the hostels generally are not able to offer the levels of therapy and support given in hospital or in designated hostels for people with mental health problems. Responses also suggest that support from Health Service personnel is less than satisfactory. While the findings in this study do not look at the entire homeless population in Northern Ireland, interesting and useful information emerged that has implications for policy and further areas of study elsewhere.
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Chak B, McAuley A, Whitcombe T. Crystal and solution structure of a pendant-armed macrocyclic complex of palladium(II). CAN J CHEM 1994. [DOI: 10.1139/v94-189] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The synthesis and X-ray crystal structure of [Pd)py2[9]aneN2S)](BF4)2 (py2[9]aneN2S = 1-thia-4,7-bis(pyridylmethyl)diaza-cyclononane) (P21/n,a = 10.233(4) Å, b = 11.484(5) Å, c = 19.913(6) Å, β = 94.03(4)°, V = 2334(2) Å3, R = 0.0705, Rw = 0.0759 ) are presented. The crystal structure indicates a long range interaction (2.92 Å) between the planar palladium and the apical sulphur atom. Although this distance is longer than the value for a Pd—S bond observed normally there is evidence for a net positive interaction provided by the solution structure as determined by NMR spectroscopy. Comparative analysis of the structural features exhibited by this complex with similar nine-membered chelating ligands emphasizes the presence of an axial Pd—S bond.
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McAuley A, Palmer T, Whitcombe T. X-ray crystal structure of [Ni(III)(cyclam)(NO3)2](ClO4) and electron transfer reactions of the Ni(III)/Ni(II) couple. CAN J CHEM 1993. [DOI: 10.1139/v93-222] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The synthesis and crystal structure of [Ni(cyclam)(NO3)2](ClO4) are described (P1, a = 8.347(4) Å, b = 15.960(7) Å, c = 7.656(3) Å, α = 90.33(6)°, β = 110.97(4)°, γ = 104.45(5)°, V = 917.0(7) Å3, R = 0.0425, Rw = 0.0384). The crystal contains two unique Ni(III) cations within the unit cell, with a network of hydrogen bonding interactions linking one of the cations into a stacked configuration while the other cation contains a strong internal hydrogen bond. This provides an interesting inorganic example of multi-site cooperative binding involving a metal complex cation. By use of electron transfer data from known outer-sphere redox reagents, measurement of the cross-reactions with [Ni(cyclam)]3+/2+ in 3 M nitrate media yielded a self-exchange rate constant of 1.4 × 105 M−1 s−1. The structural data have been utilized to obtain a calculated estimate of the self-exchange rate constant (1.0 × 108 M−1 s−1) for this couple. The relationship between these two values is explored. The lack of adiabaticity is reflected in a value ≈0.01 for κeI not only for this couple but also for other related cyclam complexes.
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McAuley A, Subramanian S, Zaworotko MJ. Coordination polymerisation of a binuclear copper(II) macrocyclic cation through self-assembly. ACTA ACUST UNITED AC 1992. [DOI: 10.1039/c39920001321] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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McAuley A, Subramanian S, Whitcombe TW. Synthesis and crystal structure of an octahedral nickel(II) complex derived from pentaerythrityl tetraamine. CAN J CHEM 1991. [DOI: 10.1139/v91-153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
not available
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McAuley A, Subramanian S, Whitcombe TW. Synthesis and crystal structure of an octahedral nickel(II) complex derived from pentaerythrityl tetraamine. CAN J CHEM 1989. [DOI: 10.1139/v89-253] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The Ni(II) complex, Ni(Htam)24+ (tam = pentaerythrityl tetraamine), has been prepared under controlled conditions. In this ion, three of the four amino groups of each ligand are coordinated to yield an octahedral structure which shows tetragonal and trigonal distortion. The fourth amino group is protonated in each case and binds strongly to the counter ion SO42−. The crystal structure (triclinic, [Formula: see text], a = 8.913(3), b = 9.775(2), c = 7.505(3), α = 102.61(4)°, β = 106.28(4)°, γ = 96.40(3)°) has been refined, converging to final values of R = 0.0347 and Rw = 0.0386. The three dimensional nature of the hydrogen bonding in the crystal structure has been described. Differences in Ni—N bond lengths are observed. A transient nickel(III) species is generated chemically or electrochemically. The esr spectrum is consistent with a low spin d7 centre and is axial in nature. Keywords: nickel, pentaerythrityl tetraamine, hydrogen bonding, oxidation.
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