J. Pessoa, I. Correia, T. Kiss, T. Jakusch, M. Castro, C. Geraldes
By reaction of salicylaldehyde and GlyGly or GlyGlyGly, followed by reduction with NaBH4, N-salicyl-glycylglycine 1 and N-salicyl-glycylglycylglycine 2, the reduced Schiff bases H2sal-RGG and H2sal-RGGG, containing the GlyGly or GlyGlyGly moities, are prepared and characterised. Their acid–base properties and complexation with VIVO2+ and CuII are studied by pH-potentiometry, visible absorption and EPR spectrometries, and the protonation and complex formation constants are determined. Vanadium and copper complexes are also prepared and characterised. Differences in the metal binding abilities of 1 and 2 are found. Amide deprotonation is proved but its extent depends on the system, being particularly important in the M–H2sal-RGG systems with the formation of the (O-phenolate, N-amine, N-amide, COO−) (6+5+5)-membered joined chelate system. Depending on the system, at physiological pH this binding mode and/or 2 × (O-phenolate, N-amine) are dominant. The aminophenolate chelates formed with sal-RGG and sal-RGGG behave as anchoring donor sites and the ML and ML2 complexes, involving O-phenolate, N-amine chelation, form in higher relative concentration than in the corresponding M–GlyGly or M–GlyGlyGly systems. Moreover, while for the VIVO–H2sal-RGG system the N-amide deprotonation/co-ordination is strongly promoted, it is not so favoured in the CuII–H2sal-RGG and CuII–H2sal-RGGG systems. The increased stability induced by the additional O-phenolate donor is particularly relevant for sal-RGG and hydrolysis of the MLH−1 complexes starts several pH units higher than in the GlyGly systems. In contrast to VIV, the VV complexes formed with sal-RGGG were found to be more stable than those of sal-RGG.
{"title":"Oxovanadium(IV and V) and copper(II) complexes of N-salicyl-glycylglycine and N-salicyl-glycylglycylglycine","authors":"J. Pessoa, I. Correia, T. Kiss, T. Jakusch, M. Castro, C. Geraldes","doi":"10.1039/B206835B","DOIUrl":"https://doi.org/10.1039/B206835B","url":null,"abstract":"By reaction of salicylaldehyde and GlyGly or GlyGlyGly, followed by reduction with NaBH4, N-salicyl-glycylglycine 1 and N-salicyl-glycylglycylglycine 2, the reduced Schiff bases H2sal-RGG and H2sal-RGGG, containing the GlyGly or GlyGlyGly moities, are prepared and characterised. Their acid–base properties and complexation with VIVO2+ and CuII are studied by pH-potentiometry, visible absorption and EPR spectrometries, and the protonation and complex formation constants are determined. Vanadium and copper complexes are also prepared and characterised. Differences in the metal binding abilities of 1 and 2 are found. Amide deprotonation is proved but its extent depends on the system, being particularly important in the M–H2sal-RGG systems with the formation of the (O-phenolate, N-amine, N-amide, COO−) (6+5+5)-membered joined chelate system. Depending on the system, at physiological pH this binding mode and/or 2 × (O-phenolate, N-amine) are dominant. The aminophenolate chelates formed with sal-RGG and sal-RGGG behave as anchoring donor sites and the ML and ML2 complexes, involving O-phenolate, N-amine chelation, form in higher relative concentration than in the corresponding M–GlyGly or M–GlyGlyGly systems. Moreover, while for the VIVO–H2sal-RGG system the N-amide deprotonation/co-ordination is strongly promoted, it is not so favoured in the CuII–H2sal-RGG and CuII–H2sal-RGGG systems. The increased stability induced by the additional O-phenolate donor is particularly relevant for sal-RGG and hydrolysis of the MLH−1 complexes starts several pH units higher than in the GlyGly systems. In contrast to VIV, the VV complexes formed with sal-RGGG were found to be more stable than those of sal-RGG.","PeriodicalId":17317,"journal":{"name":"Journal of The Chemical Society-dalton Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74222020","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. Blake, F. Devillanova, A. Garau, A. Harrison, F. Isaia, V. Lippolis, S. K. Tiwary, M. Schröder, G. Verani, G. Whittaker
The substitution reactions of the coordinated acetonitrile molecule in [Ni(L)(MeCN)][BF4]2 (1) {L = 2,5,8-trithia[9],(2,9)-1,10-phenanthrolinophane} with three potentially bidentate ligands L′ (L′ = N3−, 4,4′-bipyridine and F−) have been studied both in solution and in the solid state with the aim of verifying the potential of 1 as a starting material for the synthesis of [{Ni(L)}2L′]n+ (n = 3, 4) NiII-binuclear compounds. While the mononuclear [Ni(L)(N3)]BF4 complex was isolated in the solid state from the reaction of 1 with N3−, the binuclear [{Ni(L)}2F][BF4]3·MeCN·H2O and [{Ni(L)}2(4,4′-bipy)][BF4]4 compounds have been obtained from the reactions of 1 with F− and 4,4′-bipy, respectively. The first two complexes have been characterised by X-ray diffraction studies. In [Ni(L)(N3)]+, a distorted octahedral geometry is achieved at the NiII, with five sites occupied by the macrocyclic ligand L and the sixth by a monodentate azide group. In [{Ni(L)}2F]3+, two [Ni(L)]2+ units are bridged by a fluoride ligand to give only the second example of a singly F-bridged NiII dimer. The magnetisation of [{Ni(L)}2F][BF4]3·MeCN·H2O and of [{Ni(L)}2(4,4′-bipy)][BF4]4 has been recorded over the temperature range 1.8–300 K and indicates a significant antiferromagnetic exchange in the former.
{"title":"[Ni(L)(MeCN)][BF4]2 {L = 2,5,8-trithia[9],(2,9)-1,10-phenanthrolinophane} as a building block for the synthesis of binuclear nickel(II) complexes: X-ray crystal structure and magnetochemistry of a singly F-bridged nickel(II) dimer","authors":"A. Blake, F. Devillanova, A. Garau, A. Harrison, F. Isaia, V. Lippolis, S. K. Tiwary, M. Schröder, G. Verani, G. Whittaker","doi":"10.1039/B207934H","DOIUrl":"https://doi.org/10.1039/B207934H","url":null,"abstract":"The substitution reactions of the coordinated acetonitrile molecule in [Ni(L)(MeCN)][BF4]2 \u0000(1) \u0000{L = 2,5,8-trithia[9],(2,9)-1,10-phenanthrolinophane} with three potentially bidentate ligands L′ \u0000(L′ \u0000= N3−, 4,4′-bipyridine and F−) have been studied both in solution and in the solid state with the aim of verifying the potential of 1 as a starting material for the synthesis of [{Ni(L)}2L′]n+ \u0000(n \u0000= 3, 4) NiII-binuclear compounds. While the mononuclear [Ni(L)(N3)]BF4 complex was isolated in the solid state from the reaction of 1 with N3−, the binuclear [{Ni(L)}2F][BF4]3·MeCN·H2O and [{Ni(L)}2(4,4′-bipy)][BF4]4 compounds have been obtained from the reactions of 1 with F− and 4,4′-bipy, respectively. The first two complexes have been characterised by X-ray diffraction studies. In [Ni(L)(N3)]+, a distorted octahedral geometry is achieved at the NiII, with five sites occupied by the macrocyclic ligand L and the sixth by a monodentate azide group. In [{Ni(L)}2F]3+, two [Ni(L)]2+ units are bridged by a fluoride ligand to give only the second example of a singly F-bridged NiII dimer. The magnetisation of [{Ni(L)}2F][BF4]3·MeCN·H2O and of [{Ni(L)}2(4,4′-bipy)][BF4]4 has been recorded over the temperature range 1.8–300 K and indicates a significant antiferromagnetic exchange in the former.","PeriodicalId":17317,"journal":{"name":"Journal of The Chemical Society-dalton Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89092464","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 stoichiometric perovskites RMnO3 (R = rare earth) experience Jahn–Teller (JT) transitions as a function of temperature and R size similar to that recently described for LaMnO3. We have investigated the JT transition for R = Pr by ATD techniques and neutron powder diffraction. This transition takes place at approximately 1050 K, and it is characterized by a strong reduction of the MnO6 octahedra and sudden changes in the unit cell parameters and Mn–O bond distances. For T TJT, we observe an orthorhombic O-type structure, with much less distorted MnO6 octahedra and a < c/√2 < b. In contrast to LaMnO3, the lattice parameters do not converge to give a metrically cubic unit cell above the transition, probably due to the higher mismatch between ionic radii (steric effect)
{"title":"Neutron-diffraction study of the Jahn–Teller transition in PrMnO3","authors":"D. Sánchez, J. Alonso, M. J. Martínez-Lope","doi":"10.1039/B208660N","DOIUrl":"https://doi.org/10.1039/B208660N","url":null,"abstract":"The stoichiometric perovskites RMnO3 \u0000(R = rare earth) experience Jahn–Teller (JT) transitions as a function of temperature and R size similar to that recently described for LaMnO3. We have investigated the JT transition for R = Pr by ATD techniques and neutron powder diffraction. This transition takes place at approximately 1050 K, and it is characterized by a strong reduction of the MnO6 octahedra and sudden changes in the unit cell parameters and Mn–O bond distances. For T TJT, we observe an orthorhombic O-type structure, with much less distorted MnO6 octahedra and a < c/√2 < b. In contrast to LaMnO3, the lattice parameters do not converge to give a metrically cubic unit cell above the transition, probably due to the higher mismatch between ionic radii (steric effect)","PeriodicalId":17317,"journal":{"name":"Journal of The Chemical Society-dalton Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86526520","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 variable-pressure kinetic study of the complexation of bromide with Rh3+(aq) (I = 2.03 mol dm−3 (NaClO4−), range 0.1–206.8 MPa) as a function of [H+] (0.06–1.00 mol dm−3) at 70 °C is reported. The final product is trans-[Rh(OH2)4Br2]+ with formation of the bromopentaaqua ion rate determining. The decrease in the extent of rate saturation with [Br−] observed on lowering [H+] below 0.20 mol dm−3 is consistent with greater participation from the more labile pentaaquahydroxo ion in a parallel ion-pair interchange processes with the hexaaqua ion but with Kos (RhOH2+–Br−) < Kos (Rh3+–Br−). Complexation on the hexaaqua ion is associatively activated (ΔV‡I = −3.3 ± 1.0 cm3 mol−1) but dissociatively activated on the pentaaquahydroxo species (ΔV‡IOH = +7.7 ± 1.0 cm3 mol−1). These findings support the recent ab-initio calculations by Rotzinger et al. and variable-pressure kinetic study of the water exchange process by Merbach et al. which indicate a favourable Ia pathway for low-spin [Rh(OH2)6]3+ despite its t2g6 configuration. Earlier proposals of a D process for both ions on the basis of the observed rate saturation can now be discounted and the present findings lend further compelling support for the use of the activation volume as a powerful mechanistic probe. Reasons for the greater penetration by the entering donor within replacement reactions on 4d and 5d M3+ complexes are considered.
{"title":"Variable-pressure kinetic study of bromide complexation on aquarhodium(III)","authors":"Stuart C. Galbraith, Craig R. Robson, D. Richens","doi":"10.1039/B207017K","DOIUrl":"https://doi.org/10.1039/B207017K","url":null,"abstract":"A variable-pressure kinetic study of the complexation of bromide with Rh3+(aq) \u0000(I \u0000= 2.03 mol dm−3 \u0000(NaClO4−), range 0.1–206.8 MPa) as a function of [H+] \u0000(0.06–1.00 mol dm−3) at 70 °C is reported. The final product is trans-[Rh(OH2)4Br2]+ with formation of the bromopentaaqua ion rate determining. The decrease in the extent of rate saturation with [Br−] observed on lowering [H+] below 0.20 mol dm−3 is consistent with greater participation from the more labile pentaaquahydroxo ion in a parallel ion-pair interchange processes with the hexaaqua ion but with Kos \u0000(RhOH2+–Br−) < Kos \u0000(Rh3+–Br−). Complexation on the hexaaqua ion is associatively activated (ΔV‡I \u0000= \u0000−3.3 ± 1.0 cm3 mol−1) but dissociatively activated on the pentaaquahydroxo species (ΔV‡IOH \u0000= \u0000+7.7 ± 1.0 cm3 mol−1). These findings support the recent ab-initio calculations by Rotzinger et al. and variable-pressure kinetic study of the water exchange process by Merbach et al. which indicate a favourable Ia pathway for low-spin [Rh(OH2)6]3+ despite its t2g6 configuration. Earlier proposals of a D process for both ions on the basis of the observed rate saturation can now be discounted and the present findings lend further compelling support for the use of the activation volume as a powerful mechanistic probe. Reasons for the greater penetration by the entering donor within replacement reactions on 4d and 5d M3+ complexes are considered.","PeriodicalId":17317,"journal":{"name":"Journal of The Chemical Society-dalton Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81731501","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}
R. Dinda, P. Sengupta, Saktiprosad Ghosh, H. Mayer-Figge, W. Sheldrick
The salicylhydrazone of anthranilhydrazide (H2L) reacted with MoO2(acac)2 in refluxing alcohols to yield compounds of the general formula MoO2L(ROH) (where R = CH3, C2H5, n-C3H7, n-C4H9). The complex MoO2L(C2H5OH) is found to undergo facile reaction with heterocyclic bases to form MoO2L(Q)-type complexes where Q = pyridine, 4-picoline, imidazole and substituted imidazoles. Single crystal X-ray structural studies on the ligand H2L (1) and the complexes MoO2L(C2H5OH) (2) and MoO2L(Imz) (3) indicate that the free ligand exists in its keto form, but in the two complexes 2 and 3 the ligand coordinates to the MoO22+ core through the enolate oxygen, the phenolate oxygen and the azomethine nitrogen. Reaction of MoO2L(C2H5OH) with PPh3 in CH3CN under dry dinitrogen, in the absence and presence of bipy, produced MoIVOL (2a) (brown) and MoIVOL(bipy) (2b) (green) respectively along with Ph3PO. This reaction is reminiscent of the oxotransfer reaction from the MoO2+2 core of a molybdoenzyme to the substrate PPh3. Complexes 2 and 3 crystallized in the P21/n and P21/c space groups respectively and for both of them Z = 4. The structures clearly show that 2 and 3 have distorted octahedral coordination environments in which the Mo–O(ethanol) bond of 2 and the Mo–N (imidazole) bond of 3 are significantly longer than is usually observed. This is indicative of the weak bonding of ethanol and imidazole to the MoO22+ core and points to the inherent weakness of the sixth coordination position of the coordination polyhedron of the MoO22+ core in MoO2L(C2H5OH) and MoO2L(Imz).
{"title":"A family of mononuclear molybdenum-(VI), and -(IV) oxo complexes with a tridentate (ONO) ligand","authors":"R. Dinda, P. Sengupta, Saktiprosad Ghosh, H. Mayer-Figge, W. Sheldrick","doi":"10.1039/B207129K","DOIUrl":"https://doi.org/10.1039/B207129K","url":null,"abstract":"The salicylhydrazone of anthranilhydrazide (H2L) reacted with MoO2(acac)2 in refluxing alcohols to yield compounds of the general formula MoO2L(ROH) \u0000(where R = CH3, C2H5, n-C3H7, n-C4H9). The complex MoO2L(C2H5OH) is found to undergo facile reaction with heterocyclic bases to form MoO2L(Q)-type complexes where Q = pyridine, 4-picoline, imidazole and substituted imidazoles. Single crystal X-ray structural studies on the ligand H2L (1) and the complexes MoO2L(C2H5OH) \u0000(2) and MoO2L(Imz) \u0000(3) indicate that the free ligand exists in its keto form, but in the two complexes 2 and 3 the ligand coordinates to the MoO22+ core through the enolate oxygen, the phenolate oxygen and the azomethine nitrogen. Reaction of MoO2L(C2H5OH) with PPh3 in CH3CN under dry dinitrogen, in the absence and presence of bipy, produced MoIVOL (2a) \u0000(brown) and MoIVOL(bipy) \u0000(2b) \u0000(green) respectively along with Ph3PO. This reaction is reminiscent of the oxotransfer reaction from the MoO2+2 core of a molybdoenzyme to the substrate PPh3. Complexes 2 and 3 crystallized in the P21/n and P21/c space groups respectively and for both of them Z \u0000= 4. The structures clearly show that 2 and 3 have distorted octahedral coordination environments in which the Mo–O(ethanol) bond of 2 and the Mo–N (imidazole) bond of 3 are significantly longer than is usually observed. This is indicative of the weak bonding of ethanol and imidazole to the MoO22+ core and points to the inherent weakness of the sixth coordination position of the coordination polyhedron of the MoO22+ core in MoO2L(C2H5OH) and MoO2L(Imz).","PeriodicalId":17317,"journal":{"name":"Journal of The Chemical Society-dalton Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90662211","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}
F. Taube, I. Andersson, I. Tóth, A. Bodor, O. Howarth, L. Pettersson
The equilibrium speciation at 278 K and the dynamics in the systems pH++qMoO42–+rH2O2+sL (H+)p(MoO42–)q(H2O2)r Ls(L = SO42– or Cl–) in 0.3 M Na2(SO4) and 0.6 M Na(Cl) medium has been determined fro ...
测定了在0.3 M Na2(SO4)和0.6 M Na(Cl)介质中pH++qMoO42 - +rH2O2+sL (H+)p(MoO42 -)q(H2O2)r Ls(L = SO42 -或Cl -)体系在278 K时的平衡形态和动力学。
{"title":"Equilibria and dynamics of some aqueous peroxomolybdate catalysts: a 17O NMR spectroscopic study","authors":"F. Taube, I. Andersson, I. Tóth, A. Bodor, O. Howarth, L. Pettersson","doi":"10.1039/B206230E","DOIUrl":"https://doi.org/10.1039/B206230E","url":null,"abstract":"The equilibrium speciation at 278 K and the dynamics in the systems pH++qMoO42–+rH2O2+sL (H+)p(MoO42–)q(H2O2)r Ls(L = SO42– or Cl–) in 0.3 M Na2(SO4) and 0.6 M Na(Cl) medium has been determined fro ...","PeriodicalId":17317,"journal":{"name":"Journal of The Chemical Society-dalton Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87046617","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}
Reactions of N-methyl-iminobis(methylenephosphonic acid), CH3N(CH2PO3H2)2, (H4L) with divalent metal nitrates in aqueous solution afforded two new metal diphosphonates with different structures. Zn(H2L)(H2O) (1) features a 1D double chain built from ZnO4 tetrahedra cross-linked by bridging phosphonate groups and ligands. Each zinc cation is tetrahedrally coordinated by three phosphonate oxygen atoms from three ligands and an aqua ligand. These double chains are interconnected into a layer through N–H⋯O and O–H⋯O hydrogen bonds. In Cd(H3L)2·2H2O (2) the Cd(II) ion is octahedrally coordinated by six phosphonate oxygen atoms from four ligands, two of them in a bidentate and two in a unidentate fashion. Each CdO6 octahedron is further linked to four neighboring CdO6 octahedra through four bridging phosphonate groups, resulting in a two-dimensional metal phosphonate (002) layer. These layers are held together by strong hydrogen bonds between uncoordinated phosphonate oxygen atoms. The effect of the extent of deprotonation of phosphonic acids on the type of complex formed is discussed.
n -甲基亚胺obis(亚甲基膦酸)、CH3N(CH2PO3H2)2、(H4L)与二价金属硝酸盐在水溶液中反应得到两种结构不同的新型金属二磷酸盐。Zn(H2L)(H2O)(1)是由磷酸基与配体交联的ZnO4四面体组成的一维双链。每个锌阳离子是由来自三个配体和一个水配体的三个磷酸盐氧原子四面体配位的。这些双链通过N-H⋯O和O - h⋯O氢键相互连接成一层。在Cd(H3L)2·2H2O(2)中，Cd(II)离子由来自四个配体的六个磷酸盐氧原子八面配位，其中两个是双齿配位，另外两个是不确定配位。每个CdO6八面体通过四个桥接磷酸基团进一步连接到四个相邻的CdO6八面体，形成二维金属膦酸盐(002)层。这些层是由不配位的磷酸盐氧原子之间的强氢键结合在一起的。讨论了膦酸去质子化程度对形成络合物类型的影响。
{"title":"The role of deprotonation of the ligand on the structures of metal phosphonates: synthesis, characterization and crystal structures of two new metal diphosphonates with a 1D double chain and a 2D layer structure","authors":"J. Mao, Zhike Wang, A. Clearfield","doi":"10.1039/B204270N","DOIUrl":"https://doi.org/10.1039/B204270N","url":null,"abstract":"Reactions of N-methyl-iminobis(methylenephosphonic acid), CH3N(CH2PO3H2)2, (H4L) with divalent metal nitrates in aqueous solution afforded two new metal diphosphonates with different structures. Zn(H2L)(H2O) (1) features a 1D double chain built from ZnO4 tetrahedra cross-linked by bridging phosphonate groups and ligands. Each zinc cation is tetrahedrally coordinated by three phosphonate oxygen atoms from three ligands and an aqua ligand. These double chains are interconnected into a layer through N–H⋯O and O–H⋯O hydrogen bonds. In Cd(H3L)2·2H2O (2) the Cd(II) ion is octahedrally coordinated by six phosphonate oxygen atoms from four ligands, two of them in a bidentate and two in a unidentate fashion. Each CdO6 octahedron is further linked to four neighboring CdO6 octahedra through four bridging phosphonate groups, resulting in a two-dimensional metal phosphonate (002) layer. These layers are held together by strong hydrogen bonds between uncoordinated phosphonate oxygen atoms. The effect of the extent of deprotonation of phosphonic acids on the type of complex formed is discussed.","PeriodicalId":17317,"journal":{"name":"Journal of The Chemical Society-dalton Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86526688","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}
Huizhang Liu, M. J. Calhorda, M. Drew, V. Félix, J. Novosad, L. Veiros, F. D. Biani, P. Zanello
New Cu(I) and Ag(I) binuclear complexes were prepared by reaction of [M(NCCH3)4][PF6] (M = Ag, Cu) with the bidentate phosphine ligands Ph2PNHPPh2 (dppa) and Ph2PCH2PPh2 (dppm). In the reaction of Cu(I) with dppa the phosphine is easily oxidized to give the octahedral species of [Cu(dppaO2)3][PF6], 1. In an inert atmosphere, the binuclear complexes [Cu2(dppa)2(NCCH3)3][PF6]2, 2, [Cu2(dppa)2(NCCH3)4][PF6]2, 3, [Ag2(dppa)2(NCCH3)2][PF6]2, 4, and [Ag2(dppm)2][PF6]2, 5, were formed and structurally characterized by X-ray diffraction (except for 5). The electrochemical studies showed that the most relevant property of the binuclear species was the ease of forming the metal upon reduction. EH and DFT calculations were performed in order to try and understand the structural features of the [M2(dppa)2(NCCH3)x]n+ complexes, including the 0.47 A increase in M⋯M distance upon going from 2 to 3.
{"title":"New Cu(I) and Ag(I) binuclear complexes containing the dppa ligand","authors":"Huizhang Liu, M. J. Calhorda, M. Drew, V. Félix, J. Novosad, L. Veiros, F. D. Biani, P. Zanello","doi":"10.1039/B205922N","DOIUrl":"https://doi.org/10.1039/B205922N","url":null,"abstract":"New Cu(I) and Ag(I) binuclear complexes were prepared by reaction of [M(NCCH3)4][PF6] (M = Ag, Cu) with the bidentate phosphine ligands Ph2PNHPPh2 (dppa) and Ph2PCH2PPh2 (dppm). In the reaction of Cu(I) with dppa the phosphine is easily oxidized to give the octahedral species of [Cu(dppaO2)3][PF6], 1. In an inert atmosphere, the binuclear complexes [Cu2(dppa)2(NCCH3)3][PF6]2, 2, [Cu2(dppa)2(NCCH3)4][PF6]2, 3, [Ag2(dppa)2(NCCH3)2][PF6]2, 4, and [Ag2(dppm)2][PF6]2, 5, were formed and structurally characterized by X-ray diffraction (except for 5). The electrochemical studies showed that the most relevant property of the binuclear species was the ease of forming the metal upon reduction. EH and DFT calculations were performed in order to try and understand the structural features of the [M2(dppa)2(NCCH3)x]n+ complexes, including the 0.47 A increase in M⋯M distance upon going from 2 to 3.","PeriodicalId":17317,"journal":{"name":"Journal of The Chemical Society-dalton Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90245773","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}
J. Atwood, L. Barbour, S. Dalgarno, C. Raston, Helen R. Webb
New structural motifs incorporating trivalent lanthanoid ions and p-sulfonatocalix[4]arene, derived from solutions with or without potential host molecules for the calixarene, notably 18-crown-6, 1-aza-18-crown-6, and cryptand[2.2.2], have been authenticated. These include coordination polymers which form bi-layer sheet structures and an unprecedented combined ‘ferris wheel’ and ‘molecular capsule’ structure for Ce3+ which incorporates two previously reported structural motifs associated with this type of chemistry, respectively for elements to the left and right of cerium in the lanthanide series.
{"title":"Supramolecular assemblies of p-sulfonatocalix[4]arene with aquated trivalent lanthanide ions","authors":"J. Atwood, L. Barbour, S. Dalgarno, C. Raston, Helen R. Webb","doi":"10.1039/B206129E","DOIUrl":"https://doi.org/10.1039/B206129E","url":null,"abstract":"New structural motifs incorporating trivalent lanthanoid ions and p-sulfonatocalix[4]arene, derived from solutions with or without potential host molecules for the calixarene, notably 18-crown-6, 1-aza-18-crown-6, and cryptand[2.2.2], have been authenticated. These include coordination polymers which form bi-layer sheet structures and an unprecedented combined ‘ferris wheel’ and ‘molecular capsule’ structure for Ce3+ which incorporates two previously reported structural motifs associated with this type of chemistry, respectively for elements to the left and right of cerium in the lanthanide series.","PeriodicalId":17317,"journal":{"name":"Journal of The Chemical Society-dalton Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83295924","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}
Christine Archambault, R. Bender, P. Braunstein, Y. Dusausoy
The doubly-bridged, dinuclear complex [Pt2(μ-PPh2)(μ-o-C6H4PPh2)(PPh3)2] (1) reacts with electrophiles such as H+ or [M(PPh3)]+ (M = Cu, Ag, Au) first at the metal–metal bond. This is supported by an X-ray diffraction study of [Pt2{μ-Cu(PPh3)}(μ-PPh2)(μ-o-C6H4PPh2)(PPh3)2]PF6 (2) which reveals a Pt2Cu triangular metal core and, unexpectedly, a bonding interaction between the Cu atom and the Cipso of the orthometalated phenyl. This confers a tetrahedral-like geometry to the Cu atom. In the neutral complex [Pt2{μ-AgOC(O)CF3}(μ-PPh2)(μ-o-C6H4PPh2)(PPh3)2] (3), the silver atom is coordinated by the terminally bound trifluorocarboxylate anion. Reactions of 1 in a polar solvent with 2 equiv. of acid HA, where A is a weakly nucleophilic anion, afforded the dicationic solvento adducts [Pt2(μ-H)(μ-PPh2)(Solv)(PPh3)3]A2 (5a, Solv = THF, A = PF6; 5b, Solv = CH2Cl2, A = BF4; 5c, Solv = acetone, A = BF4) which result from rupture of the Pt–C σ bond and transformation of the cyclometalated bridging ligand into PPh3. The coordinated solvent molecule is readily displaced by nucleophiles such as PO2F2−, CF3SO3−, Cl− or Br−, thus forming monocationic complexes, 6–9, respectively. An X-ray diffraction study on [Pt2(μ-H)(μ-PPh2)(OPOF2)(PPh3)3](PF6)·0.5CH2Cl2 (6·0.5CH2Cl2) establishes that the OPOF2 group is linked by one O atom to platinum, to our knowledge an unprecedented feature.
{"title":"Reactivity of phosphido-bridged diplatinum complexes towards electrophiles: synthesis of new hydrides and related Pt2Cu and Pt2Ag clusters","authors":"Christine Archambault, R. Bender, P. Braunstein, Y. Dusausoy","doi":"10.1039/B206347F","DOIUrl":"https://doi.org/10.1039/B206347F","url":null,"abstract":"The doubly-bridged, dinuclear complex [Pt2(μ-PPh2)(μ-o-C6H4PPh2)(PPh3)2] (1) reacts with electrophiles such as H+ or [M(PPh3)]+ \u0000(M = Cu, Ag, Au) first at the metal–metal bond. This is supported by an X-ray diffraction study of [Pt2{μ-Cu(PPh3)}(μ-PPh2)(μ-o-C6H4PPh2)(PPh3)2]PF6 (2) which reveals a Pt2Cu triangular metal core and, unexpectedly, a bonding interaction between the Cu atom and the Cipso of the orthometalated phenyl. This confers a tetrahedral-like geometry to the Cu atom. In the neutral complex [Pt2{μ-AgOC(O)CF3}(μ-PPh2)(μ-o-C6H4PPh2)(PPh3)2] (3), the silver atom is coordinated by the terminally bound trifluorocarboxylate anion. Reactions of 1 in a polar solvent with 2 equiv. of acid HA, where A is a weakly nucleophilic anion, afforded the dicationic solvento adducts [Pt2(μ-H)(μ-PPh2)(Solv)(PPh3)3]A2 \u0000(5a, Solv = THF, A = PF6; 5b, Solv = CH2Cl2, A = BF4; 5c, Solv = acetone, A = BF4) which result from rupture of the Pt–C σ bond and transformation of the cyclometalated bridging ligand into PPh3. The coordinated solvent molecule is readily displaced by nucleophiles such as PO2F2−, CF3SO3−, Cl− or Br−, thus forming monocationic complexes, 6–9, respectively. An X-ray diffraction study on [Pt2(μ-H)(μ-PPh2)(OPOF2)(PPh3)3](PF6)·0.5CH2Cl2 \u0000(6·0.5CH2Cl2) establishes that the OPOF2 group is linked by one O atom to platinum, to our knowledge an unprecedented feature.","PeriodicalId":17317,"journal":{"name":"Journal of The Chemical Society-dalton Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75698990","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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