A. Batsanov, S. Cornet, K. B. Dillon, A. Goeta, P. Hazendonk, A. Thompson
Several new P or As compounds containing the 2,4,6-(CF3)3C6H2 (Ar), 2,6-(CF3)2C6H3 (Ar′) and/or 2,4-(CF3)2C6H3 (Ar″) ligands have been synthesised, and characterised by multinuclear NMR spectroscopy and (for all isolated compounds) elemental analysis. The crystal and molecular structures of ArPBr21, Ar2PCl 2, Ar″2PCl 3, Ar″2PBr 4, Ar′Ar″AsCl 5, Ar′Ar″AsBr 6 and Ar′Ar″AsH 7 have been determined by single-crystal X-ray diffraction. A particularly interesting feature of these structures is close contacts between ortho-fluorines and the P or As atoms, as observed previously in Ar′Ar″PCl and Ar2AsCl.
{"title":"New group 15 compounds containing the 2,4,6-(CF3)3C6H2 (fluoromes = Ar), 2,6-(CF3)2C6H3 (fluoroxyl = Ar′) or 2,4-(CF3)2C6H3 (Ar″) ligands","authors":"A. Batsanov, S. Cornet, K. B. Dillon, A. Goeta, P. Hazendonk, A. Thompson","doi":"10.1039/B207327G","DOIUrl":"https://doi.org/10.1039/B207327G","url":null,"abstract":"Several new P or As compounds containing the 2,4,6-(CF3)3C6H2 \u0000(Ar), 2,6-(CF3)2C6H3 \u0000(Ar′) and/or 2,4-(CF3)2C6H3 \u0000(Ar″) ligands have been synthesised, and characterised by multinuclear NMR spectroscopy and (for all isolated compounds) elemental analysis. The crystal and molecular structures of ArPBr21, Ar2PCl 2, Ar″2PCl 3, Ar″2PBr 4, Ar′Ar″AsCl 5, Ar′Ar″AsBr 6 and Ar′Ar″AsH 7 have been determined by single-crystal X-ray diffraction. A particularly interesting feature of these structures is close contacts between ortho-fluorines and the P or As atoms, as observed previously in Ar′Ar″PCl and Ar2AsCl.","PeriodicalId":17317,"journal":{"name":"Journal of The Chemical Society-dalton Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84666773","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The protonation and complex formation equilibria of N,N′-ethylenediaminedisuccinic acid (EDDS) in the isomeric form [S,S] and a mixture of EDDS isomers (25% [S,S], 50% [R,S], 25% [R,R]) with Fe(III), Cu(II), Zn(II) and Mn(II) have been studied in aqueous 0.1 M NaCl solution at 25 °C by potentiometric titrations. The calculations were carried out with the computer program SUPERQUAD.
用电位滴定法研究了N,N′-乙二胺二丁二酸(EDDS)在25℃0.1 M NaCl水溶液中与Fe(III)、Cu(II)、Zn(II)和Mn(II)在同分异构体[S,S]和EDDS异构体混合物(25% [S,S]、50% [R,S]、25% [R,R])的质子化平衡和络合物形成平衡。计算是用SUPERQUAD计算机程序进行的。
{"title":"Complexation of [S,S] and mixed stereoisomers of N,N′-ethylenediaminedisuccinic acid (EDDS) with Fe(III), Cu(II), Zn(II) and Mn(II) ions in aqueous solution","authors":"M. Orama, H. Hyvönen, H. Saarinen, R. Aksela","doi":"10.1039/B207777A","DOIUrl":"https://doi.org/10.1039/B207777A","url":null,"abstract":"The protonation and complex formation equilibria of N,N′-ethylenediaminedisuccinic acid (EDDS) in the isomeric form [S,S] and a mixture of EDDS isomers (25% \u0000[S,S], 50% \u0000[R,S], 25% \u0000[R,R]) with Fe(III), Cu(II), Zn(II) and Mn(II) have been studied in aqueous 0.1 M NaCl solution at 25 °C by potentiometric titrations. The calculations were carried out with the computer program SUPERQUAD.","PeriodicalId":17317,"journal":{"name":"Journal of The Chemical Society-dalton Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82282716","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A new open-framework zincophosphate, Zn0.5(H2PO4)·0.5H2O (denoted as FJ-13), possessing intersecting three-dimensional helical channels, has been synthesized under solvothermal conditions.
{"title":"Synthesis and structure of a novel open-framework zincophosphate with intersecting three-dimensional helical channels","authors":"Zhien Lin, Youwei Yao, Jie Zhang, Guo‐Yu Yang","doi":"10.1039/B207684P","DOIUrl":"https://doi.org/10.1039/B207684P","url":null,"abstract":"A new open-framework zincophosphate, Zn0.5(H2PO4)·0.5H2O (denoted as FJ-13), possessing intersecting three-dimensional helical channels, has been synthesized under solvothermal conditions.","PeriodicalId":17317,"journal":{"name":"Journal of The Chemical Society-dalton Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75178601","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. Evans, Gwion J. Harfoot, J. McIndoe, C. McAdam, K. M. Mackay, B. K. Nicholson, B. Robinson, M. V. Tiel
PhSiH3 reacts with [Co4(CO)12] at 50 °C in hydrocarbon solvents to give [(μ4-SiPh)2Co4(CO)11], 2c, shown by an X-ray crystal structure determination to have a pseudo-octahedral Si2Co4 core. Substituted aryl-silanes behaved similarly. Mixtures of PhSiH3, H3SiC6H4SiH3 and [Co4(CO)12] in a ca. 2 ∶ 1 ∶ 2 ratio gave the dimeric cluster [{Co4(μ4-SiPh)(CO)11Si}2C6H4], 3a, which has the two Si2Co4 cores linked by a C6H4 group to give a rigid molecule which an X-ray structure analysis shows to be over 23 A long. Related dimers linked by –(CH2)8– groups were isolated from mixtures of PhSiH3, α,ω-(H3Si)2(CH2)8 and [Co4(CO)12]. Electrochemical studies show the two cluster units in 3a do not interact electronically.
{"title":"The preparation and characterisation of monomeric and linked metal carbonyl clusters containing the closo-Si2Co4 pseudo-octahedral core","authors":"C. Evans, Gwion J. Harfoot, J. McIndoe, C. McAdam, K. M. Mackay, B. K. Nicholson, B. Robinson, M. V. Tiel","doi":"10.1039/B208374B","DOIUrl":"https://doi.org/10.1039/B208374B","url":null,"abstract":"PhSiH3 reacts with [Co4(CO)12] at 50 °C in hydrocarbon solvents to give [(μ4-SiPh)2Co4(CO)11], 2c, shown by an X-ray crystal structure determination to have a pseudo-octahedral Si2Co4 core. Substituted aryl-silanes behaved similarly. Mixtures of PhSiH3, H3SiC6H4SiH3 and [Co4(CO)12] in a ca. 2 ∶ 1 ∶ 2 ratio gave the dimeric cluster [{Co4(μ4-SiPh)(CO)11Si}2C6H4], 3a, which has the two Si2Co4 cores linked by a C6H4 group to give a rigid molecule which an X-ray structure analysis shows to be over 23 A long. Related dimers linked by –(CH2)8– groups were isolated from mixtures of PhSiH3, α,ω-(H3Si)2(CH2)8 and [Co4(CO)12]. Electrochemical studies show the two cluster units in 3a do not interact electronically.","PeriodicalId":17317,"journal":{"name":"Journal of The Chemical Society-dalton Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78724109","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. L. Hinchley, P. Trickey, H. Robertson, B. A. Smart, D. Rankin, D. Leusser, B. Walfort, D. Stalke, M. Bühl, S. Obrey
The molecular structures of bis(tert-butyl)sulfurdiimide [S(NBut)2] and tris(tert-butyl)sulfurtriimide [S(NBut)3] have been investigated in the gas phase by electron diffraction and ab initio calculations, and in the solid phase by low-temperature X-ray diffraction. The structures of each were found to be similar in both phases, and the calculated structures agree well with those in the gas phase. Ab initio calculations at levels up to MP2(fc)/cc-pVTZ for S(NBut)2 predict that the E/Z conformer (Cs symmetry) is the preferred arrangement by as much as 36.5 kJ mol−1 over the E/E conformer. Important structural parameters [ab initio (re)/GED (ra)/X-ray] for the E/Z conformer of S(NBut)2 are S(1)–N(2) [152.9/153.8(3)/152.8(3) pm], S(1)–N(3) [155.5/156.5(4)/154.4(3) pm], N(2)–C(4) [147.3/146.2(4)/147.7(5) pm], N(3)–C(5) [147.9/147.0(4)/148.9(4) pm], N(2)–S(1)–N(3) [116.9/117.8(6)/117.4(2)°], S(1)–N(2)–C(4) [125.9/125.9(6)/128.1(2)°] and S(1)–N(3)–C(5) [117.1/116.7(7)/118.2(2)°]. One conformer of S(NBut)3 with C3h symmetry was located at the MP2(fc)/6-31G* level. The gas and solid-phase studies both returned C3 structures, with the butyl groups moved a little out of the SN3 plane. Important structural parameters [ab initio (re)/GED (ra)/X-ray] for S(NBut)3 are SN [152.8/153.5(3)/151.0(2), 151.0(2), 151.1(2) pm], N–C [148.7/147.2(4)/148.3(3), 148.5(3), 148.3(3) pm], C–C [152.8/150.8(2)/152.4(4), 152.6(4), 153.0(3) pm], SN–C [123.2/122.9(4)/126.2(2), 125.5(2), 126.0(2)°], C–C–C (mean) [110.4/108.3/110.0°] and NSN–C (mean) [180.0/173.0(5)/179.4°]. Theoretical predictions at the MP2(fc)/6-31G* level were used to restrain some of the refining parameters for both structures using the SARACEN method. The lowest energy structure of bis(tert-butyl)sulfurdiimide was found to be the E/Z conformer, and the structure of tris(tert-butyl)sulfurtriimide is such that each fragment with two NBut ligands has the E/Z conformation.
{"title":"Bis(tert-butyl)sulfurdiimide, S(NBut)2, and tris(tert-butyl)sulfurtriimide, S(NBut)3: structures by gas electron diffraction, X-ray crystallography and ab initio calculations","authors":"S. L. Hinchley, P. Trickey, H. Robertson, B. A. Smart, D. Rankin, D. Leusser, B. Walfort, D. Stalke, M. Bühl, S. Obrey","doi":"10.1039/B207193B","DOIUrl":"https://doi.org/10.1039/B207193B","url":null,"abstract":"The molecular structures of bis(tert-butyl)sulfurdiimide [S(NBut)2] and tris(tert-butyl)sulfurtriimide [S(NBut)3] have been investigated in the gas phase by electron diffraction and ab initio calculations, and in the solid phase by low-temperature X-ray diffraction. The structures of each were found to be similar in both phases, and the calculated structures agree well with those in the gas phase. Ab initio calculations at levels up to MP2(fc)/cc-pVTZ for S(NBut)2 predict that the E/Z conformer (Cs symmetry) is the preferred arrangement by as much as 36.5 kJ mol−1 over the E/E conformer. Important structural parameters [ab initio \u0000(re)/GED (ra)/X-ray] for the E/Z conformer of S(NBut)2 are S(1)–N(2) \u0000[152.9/153.8(3)/152.8(3) pm], S(1)–N(3) \u0000[155.5/156.5(4)/154.4(3) pm], N(2)–C(4) \u0000[147.3/146.2(4)/147.7(5) pm], N(3)–C(5) \u0000[147.9/147.0(4)/148.9(4) pm], N(2)–S(1)–N(3) \u0000[116.9/117.8(6)/117.4(2)°], S(1)–N(2)–C(4) \u0000[125.9/125.9(6)/128.1(2)°] and S(1)–N(3)–C(5) \u0000[117.1/116.7(7)/118.2(2)°]. One conformer of S(NBut)3 with C3h symmetry was located at the MP2(fc)/6-31G* level. The gas and solid-phase studies both returned C3 structures, with the butyl groups moved a little out of the SN3 plane. Important structural parameters [ab initio \u0000(re)/GED (ra)/X-ray] for S(NBut)3 are SN [152.8/153.5(3)/151.0(2), 151.0(2), 151.1(2) pm], N–C [148.7/147.2(4)/148.3(3), 148.5(3), 148.3(3) pm], C–C [152.8/150.8(2)/152.4(4), 152.6(4), 153.0(3) pm], SN–C [123.2/122.9(4)/126.2(2), 125.5(2), 126.0(2)°], C–C–C (mean) \u0000[110.4/108.3/110.0°] and NSN–C (mean) \u0000[180.0/173.0(5)/179.4°]. Theoretical predictions at the MP2(fc)/6-31G* level were used to restrain some of the refining parameters for both structures using the SARACEN method. The lowest energy structure of bis(tert-butyl)sulfurdiimide was found to be the E/Z conformer, and the structure of tris(tert-butyl)sulfurtriimide is such that each fragment with two NBut ligands has the E/Z conformation.","PeriodicalId":17317,"journal":{"name":"Journal of The Chemical Society-dalton Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76675960","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
B. Jansik, A. S. D. Merás, B. Schimmelpfennig, H. Ågren
Coupled-cluster calculations were carried at the CCSD(T)-level in order to determine the structures and vibrational spectra of the lanthanum trihalides LaF3 and LaCl3. Two different approaches were employed to describe scalar relativistic effects; the quasi-relativistic Effective Core Potential approach and the all-electron Douglas–Kroll approach. We find LaF3 to be of pyramidal structure and LaCl3 to be planar. The obtained vibrational frequencies accord well with experimental measurements except for the ν2 mode. This disagreement is attributed to the intrinsic uncertainty of harmonic frequencies of this fluxional mode as extracted from spectra which were obtained at high temperature and for matrix isolated species.
{"title":"A coupled-cluster study of lanthanum trihalide structures","authors":"B. Jansik, A. S. D. Merás, B. Schimmelpfennig, H. Ågren","doi":"10.1039/B205926F","DOIUrl":"https://doi.org/10.1039/B205926F","url":null,"abstract":"Coupled-cluster calculations were carried at the CCSD(T)-level in order to determine the structures and vibrational spectra of the lanthanum trihalides LaF3 and LaCl3. Two different approaches were employed to describe scalar relativistic effects; the quasi-relativistic Effective Core Potential approach and the all-electron Douglas–Kroll approach. We find LaF3 to be of pyramidal structure and LaCl3 to be planar. The obtained vibrational frequencies accord well with experimental measurements except for the ν2 mode. This disagreement is attributed to the intrinsic uncertainty of harmonic frequencies of this fluxional mode as extracted from spectra which were obtained at high temperature and for matrix isolated species.","PeriodicalId":17317,"journal":{"name":"Journal of The Chemical Society-dalton Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76816249","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The receptor ability of tris(pyridin-1-ium-2-ylmethyl)amine (triprotonated tris(2-pyridylmethyl)amine, H3TPA3+) toward inorganic anions such as PF6−, CF3SO3−, Br−, and Cl− was investigated. Several spectroscopic studies revealed that H3TPA3+ offered characteristic receptor selectivity in the anion complexation. Structural analysis of the receptor-anion complexes [H3TPA(PF6)](PF6)2, [H3TPA(CF3SO3)](CF3SO3)(PF6), [H3TPA(Br)](PF6)2, and [H3TPA(Cl)](PF6)2 indicated that the H3TPA3+ receptor nicely caught each anion guest (X−) in its three dimensional cavity via hydrogen bonding (X⋯H⋯N) with pyridinium groups. Treatment of the [H3TPA(X)]2+ (X = PF6− or CF3SO3−) complex with a large excess of KBr in the solid state led to the replacement of PF6− or CF3SO3− with Br− to give [H3TPA(Br)]2+, whereas Cl− in the [H3TPA(Cl)]2+ complex was not replaced. The PF6− anions located in and out of the H3TPA3+ cavity were replaced stepwise with the added Cl− or Br−anion. The strength of the hydrogen bonding increased as the pKb value of the anion decreased in the series Cl− > Br− > CF3SO3− > PF6−.
{"title":"Receptor versatility of tris(pyridin-1-ium-2-ylmethyl)amine in anion binding through hydrogen bonding","authors":"H. Sugimoto, H. Miyake, H. Tsukube","doi":"10.1039/B209331F","DOIUrl":"https://doi.org/10.1039/B209331F","url":null,"abstract":"The receptor ability of tris(pyridin-1-ium-2-ylmethyl)amine (triprotonated tris(2-pyridylmethyl)amine, H3TPA3+) toward inorganic anions such as PF6−, CF3SO3−, Br−, and Cl− was investigated. Several spectroscopic studies revealed that H3TPA3+ offered characteristic receptor selectivity in the anion complexation. Structural analysis of the receptor-anion complexes [H3TPA(PF6)](PF6)2, [H3TPA(CF3SO3)](CF3SO3)(PF6), [H3TPA(Br)](PF6)2, and [H3TPA(Cl)](PF6)2 indicated that the H3TPA3+ receptor nicely caught each anion guest (X−) in its three dimensional cavity via hydrogen bonding (X⋯H⋯N) with pyridinium groups. Treatment of the [H3TPA(X)]2+ (X = PF6− or CF3SO3−) complex with a large excess of KBr in the solid state led to the replacement of PF6− or CF3SO3− with Br− to give [H3TPA(Br)]2+, whereas Cl− in the [H3TPA(Cl)]2+ complex was not replaced. The PF6− anions located in and out of the H3TPA3+ cavity were replaced stepwise with the added Cl− or Br−anion. The strength of the hydrogen bonding increased as the pKb value of the anion decreased in the series Cl− > Br− > CF3SO3− > PF6−.","PeriodicalId":17317,"journal":{"name":"Journal of The Chemical Society-dalton Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83304639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The reaction of a series of readily available extended terpyridyl and extended triazine ligands with several d6-metal centres has been investigated. This has led to the isolation and characterisation of nine new complexes, one of which is the first reported transition metal complex to contain the 2,4,6-tris(2-pyrimidyl)-1,3,5-triazine (tpymt) ligand. Two of the new complexes have had their molecular structures confirmed via X-ray crystallography studies. It has been shown that changes in the electronic properties of the coordinated ligand results in modulation of the electrochemical and photophysical properties of the complex to which it is coordinated. Furthermore, the emission properties of extended terpyridyl complexes incorporating the [Re(CO)3(MeCN)]+ centre suggest that luminescence in these complexes is from an extended terpyridyl based intraligand state.
{"title":"Extended terpyridyl and triazine complexes of d6-metal centres","authors":"C. Metcalfe, S. E. Spey, H. Adams, Jim A. Thomas","doi":"10.1039/B208211J","DOIUrl":"https://doi.org/10.1039/B208211J","url":null,"abstract":"The reaction of a series of readily available extended terpyridyl and extended triazine ligands with several d6-metal centres has been investigated. This has led to the isolation and characterisation of nine new complexes, one of which is the first reported transition metal complex to contain the 2,4,6-tris(2-pyrimidyl)-1,3,5-triazine (tpymt) ligand. Two of the new complexes have had their molecular structures confirmed via X-ray crystallography studies. It has been shown that changes in the electronic properties of the coordinated ligand results in modulation of the electrochemical and photophysical properties of the complex to which it is coordinated. Furthermore, the emission properties of extended terpyridyl complexes incorporating the [Re(CO)3(MeCN)]+ centre suggest that luminescence in these complexes is from an extended terpyridyl based intraligand state.","PeriodicalId":17317,"journal":{"name":"Journal of The Chemical Society-dalton Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83619005","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
B. Chiari, A. Cinti, O. Crispu, F. Demartin, A. Pasini, O. Piovesana
We describe herein a series of novel pentanuclear Co(II)–Co(III) mixed-valence cationic complexes of formula [Co5L4(μ3-OH)2]+ {L2− = 2,2′-[1,1-methanediylbis(nitrilomethylidene)diphenate] or its arylmethane analogues}, obtained by controlled oxidation of [Co2L2] precursors. The [Co5(μ3-OH)2(salNO2ben)4]I·2(CH3)2CO and [Co5(μ3-OH)2(salClben)4]I·2DMF·CH2Cl2 compounds have been studied by X-ray methods and turn out to be isostructural. The structural data show that the cobalt atoms in the pentanuclear units are bridged by μ-O(phenolato) atoms and μ3-OH groups and approximate three types of co-ordination geometries: tetrahedral, octahedral and trigonal-bipyramidal. The X-ray structure of one proligand, namely 2,2′-[1,1-(4-nitrophenylmethanediyl)bis(nitrilomethylidene)diphenol] is also reported. The χT(T) behaviour of the complex with this ligand has been studied in the 4–300 K range. The data clearly show that ferromagnetic as well as (much weaker) antiferromagnetic exchange interactions occur within the cluster. A simple exchange model has been developed which nicely reproduces the experimental data.
{"title":"New pentanuclear mixed valence Co(II)–Co(III) complexes of “short” salen homologues","authors":"B. Chiari, A. Cinti, O. Crispu, F. Demartin, A. Pasini, O. Piovesana","doi":"10.1039/B206221F","DOIUrl":"https://doi.org/10.1039/B206221F","url":null,"abstract":"We describe herein a series of novel pentanuclear Co(II)–Co(III) mixed-valence cationic complexes of formula [Co5L4(μ3-OH)2]+ \u0000{L2− \u0000= 2,2′-[1,1-methanediylbis(nitrilomethylidene)diphenate] or its arylmethane analogues}, obtained by controlled oxidation of [Co2L2] precursors. The [Co5(μ3-OH)2(salNO2ben)4]I·2(CH3)2CO and [Co5(μ3-OH)2(salClben)4]I·2DMF·CH2Cl2 compounds have been studied by X-ray methods and turn out to be isostructural. The structural data show that the cobalt atoms in the pentanuclear units are bridged by μ-O(phenolato) atoms and μ3-OH groups and approximate three types of co-ordination geometries: tetrahedral, octahedral and trigonal-bipyramidal. The X-ray structure of one proligand, namely 2,2′-[1,1-(4-nitrophenylmethanediyl)bis(nitrilomethylidene)diphenol] is also reported. The χT(T) behaviour of the complex with this ligand has been studied in the 4–300 K range. The data clearly show that ferromagnetic as well as (much weaker) antiferromagnetic exchange interactions occur within the cluster. A simple exchange model has been developed which nicely reproduces the experimental data.","PeriodicalId":17317,"journal":{"name":"Journal of The Chemical Society-dalton Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86534850","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A bidentate ligand N,N′- bis(3-pyridinecarboxamide)-1,6-hexane (L) and its silver complexes have been synthesized and characterized by single crystal X-ray diffraction. Reaction of AgClO4 and L in H2O/EtOH gives rise to a coordination polymer [Ag2L3OH][ClO4]·2.5H2O. The X-ray crystal structure of the compound shows honeycomb-like networks in which four-coordinated Ag ions are linked to three-coordinated Ag ions via three ligands L. The coordination of the long ligands L to the Ag ions creates tube-like structures and the tubes of adjacent honeycomb layers are interlocked, leading to an interpenetrating network. The compound [AgL][ClO4], synthesized from CH3OH, is composed of twisted zigzag coordination polymers in which ligands L are linked by Ag ions. Ligand L displays two different conformations A and B within a single strain of polymer. The two conformers differ in the orientation of the two pyridyl-groups which are arranged periodically in the polymer in the sequence ABBABBA. The polymer chains assemble into 2-D undulating sheets via amide hydrogen bonds. Reaction between AgNO3/AgCF3SO3 and L leads to polymeric compounds [AgL][NO3] and [AgL][CF3SO3]. The compounds are composed of coordination polymers in zigzag conformation and the polymer chains assemble into undulating sheets via inter-chain hydrogen bonds. The inter-sheet Ag–Ag distances of the compounds are in the order [AgL][CF3SO3] > [AgL][ClO4] > [AgL][NO3]. The anion exchange properties of the compounds are monitored by using X-ray powder diffraction, infrared spectroscopy and elemental analysis. Our results show that the anions in [AgL][NO3] and [AgL][CF3SO3] can be totally replaced with ClO4−. However, the exchange is not reversible. In additional, inter-conversion between [AgL][NO3] and [AgL][CF3SO3] by anion exchange is shown to be unfeasible. Anion selectivity could be due to the different hydration energy of the anions and the structural reorganization involved in the conversion.
{"title":"Coordination networks of Ag(I) and N,N′- bis(3-pyridinecarboxamide)-1,6-hexane: structures and anion exchange","authors":"S. Muthu, J. Yip, J. Vittal","doi":"10.1039/B206680G","DOIUrl":"https://doi.org/10.1039/B206680G","url":null,"abstract":"A bidentate ligand N,N′- bis(3-pyridinecarboxamide)-1,6-hexane (L) and its silver complexes have been synthesized and characterized by single crystal X-ray diffraction. Reaction of AgClO4 and L in H2O/EtOH gives rise to a coordination polymer [Ag2L3OH][ClO4]·2.5H2O. The X-ray crystal structure of the compound shows honeycomb-like networks in which four-coordinated Ag ions are linked to three-coordinated Ag ions via three ligands L. The coordination of the long ligands L to the Ag ions creates tube-like structures and the tubes of adjacent honeycomb layers are interlocked, leading to an interpenetrating network. The compound [AgL][ClO4], synthesized from CH3OH, is composed of twisted zigzag coordination polymers in which ligands L are linked by Ag ions. Ligand L displays two different conformations A and B within a single strain of polymer. The two conformers differ in the orientation of the two pyridyl-groups which are arranged periodically in the polymer in the sequence ABBABBA. The polymer chains assemble into 2-D undulating sheets via amide hydrogen bonds. Reaction between AgNO3/AgCF3SO3 and L leads to polymeric compounds [AgL][NO3] and [AgL][CF3SO3]. The compounds are composed of coordination polymers in zigzag conformation and the polymer chains assemble into undulating sheets via inter-chain hydrogen bonds. The inter-sheet Ag–Ag distances of the compounds are in the order [AgL][CF3SO3] > [AgL][ClO4] > [AgL][NO3]. The anion exchange properties of the compounds are monitored by using X-ray powder diffraction, infrared spectroscopy and elemental analysis. Our results show that the anions in [AgL][NO3] and [AgL][CF3SO3] can be totally replaced with ClO4−. However, the exchange is not reversible. In additional, inter-conversion between [AgL][NO3] and [AgL][CF3SO3] by anion exchange is shown to be unfeasible. Anion selectivity could be due to the different hydration energy of the anions and the structural reorganization involved in the conversion.","PeriodicalId":17317,"journal":{"name":"Journal of The Chemical Society-dalton Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88576541","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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