The complexing properties of the phenylsquarate ligand with Ru(II), Pt(II), Gd(III) and Tb(III) ions

Williams, Avril; Hall, Lincoln A.; White, Andrew J. P.; Williams, David J.

doi:10.1016/s0020-1693(00)00391-1

Cited by 10 publications

(21 citation statements)

References 26 publications

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“…As a continuation of our efforts to identify the factors that influence the complexing properties of monosubstituted squarate ligands and their potential for producing polymeric complexes with desirable electronic and magnetic properties, we have widened our search for suitable ligands that may allow us to achieve these objectives . As part of this initiative, the complexing properties of the phenylsquarate and diphenylaminosquarate ligands and the variable-temperature magnetochemistry of their polymeric first-row transition-metal complexes have already been investigated. , These magnetochemical investigations revealed a small but measurable antiferromagnetic interaction in manganese(II) diphenylaminosquarate, {Mn[( μ -(C 6 H 5 ) 2 NC 4 O 3 ] 2 [H 2 O] 2 } n , while manganese(II) phenylsquarate, {Mn( μ -C 6 H 5 C 4 O 3 )(C 6 H 5 C 4 O 3 )(H 2 O) 3 } n , exhibited normal magnetic behavior between 2 and 300 K. This antiferromagnetism in manganese(II) diphenylaminosquarate was attributed to the enhanced electron density on the C 4 cycle of the diphenylaminosquarate ligand because of the migration of the nitrogen lone pair.…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Structure, and Magnetochemical Analysis of Selected First-Row Transition-Metal Anilino- and Anisolesquarate Compounds

et al. 2004

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The isomorphous polymeric complexes [M(mu-C(6)H(5)NHC(4)O(3))(2)(CH(3)OH)(2)](n) [M = Mn (1), Co (2), Cu (4), Zn (5)] are produced by reacting the anilinosquarate anion with the appropriate metal nitrates in a methanolic solution. Each of these complexes contains the central metal atom in a slightly distorted octahedral environment, with the coordination polyhedron consisting of four mu-1,2-bridging anilinosquarate ligands and two trans-oriented methanols. The polymer chains propagate to form a two-dimensional net of metal centers, with the conformation of the component sheets in the net being controlled by intramolecular N-H...O and O-H...O hydrogen bonds. Under reaction conditions similar to those used in the synthesis of the polymers 1, 2, 4, and 5, the nickel(II) monomer [Ni(C(6)H(5)NHC(4)O(3))(2)(H(2)O)(4)].2H(2)O (3) is produced in which each nickel center is attached to two cis-coordinated anilinosquarate and four aqua ligands in a distorted octahedral arrangement. The ligand conformation in 3 is stabilized by both intra- and intermolecular hydrogen bonding, which results in the formation of a sheet polymer having distinct hydrophobic and hydrophilic surfaces. Magnetochemical analysis of 1 and 4 reveals normal paramagnetic behavior for 1 and a very weak ferromagnetic interaction in 4; the absence of significant magnetic interactions is attributed to the distortion of the C(4) cycle of the anilinosquarate ligand (lower than C(2)(v) symmetry) in these complexes. Reaction of anisolesquarate with M(NO(3))(2).xH(2)O in acetonitrile produced the set of isomorphous salts [M(H(2)O)(6)][CH(3)OC(6)H(5)C(4)O(3)](2) [M = Mn (6), Co (7), Ni (8), Zn (9)]. The anisolesquarate anions in 6-9 are hydrogen bonded to the [M(H(2)O)(6)](2+) ions to form polymer chains, which are further linked by hydrogen bonds to form complex sheets. Complexation of the anisolesquarate ligand was not observed even when other solvents and reaction conditions were employed.

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Section: Introductionmentioning

confidence: 99%

Synthesis, Structure, and Magnetochemical Analysis of Selected First-Row Transition-Metal Anilino- and Anisolesquarate Compounds

et al. 2004

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“…Interestingly, the intrachain Tb(1)‚‚‚Tb(2) and Tb(3)‚‚‚Tb( 4 Comparison with Ln Phenylsquarates. Globally, the structures of the lanthanide anisole-(this work) and phenylsquarates 4,6 are essentially the same, consisting of interleaved polymeric chains. A small difference between analogous anisole-and phenylsquarates of both Eu and Gd is a slight perturbation of the polymer chain resulting from the different steric demands of anisole vis-a-vis phenyl which is reflected by the presence of two independent metal centers in the anisole squarates; cf.…”

Section: Resultsmentioning

confidence: 86%

“…The C 4 −C 6 bond length in all the lanthanide compounds of the anisole- and phenylsquarate ligands is the same (range 1.442−1.447 Å), indicating no change in conjugation between these ring systems. , However, the bonding pattern within the C 4 -cycle of the Ln anisolesquarate complexes is slightly different from that in the Ln phenylsquarate complexes. In the former, there is a pattern of one short, one intermediate, and two long while in the latter the pattern is two short and two long. , …”

Section: Resultsmentioning

confidence: 92%

“…This series of lanthanide anisolesquarate complexes potentially provides another example of the effect of the steric requirements of the monosubstituted squarate ligand on structure. − The decrease in ionic radius on going from La(III) (1.016 Å) to Eu(III) (0.950 Å) to Gd(III) (0.938 Å) is reflected in a shortening of the intrachain Ln···Ln separation from 8.80 Å ( 1 ) to 8.55 Å ( 2 ) to 8.58 Å ( 3 ). The polymer chain, however, is flexible enough to accommodate these changes without a marked change to the overall structure.…”

Section: Resultsmentioning

confidence: 99%

“…Our interest in the synthesis of polymeric lanthanide complexes of monosubstituted squarate ligands is their perceived potential for exhibiting interesting electronic properties, such as semiconductivity, which could be tuned by the appropriate alteration of the ligand substituent . For example, analysis of several series of such complexes that we have synthesized so far has revealed that the steric bulk of the substituent is a particularly important factor in influencing not only whether polymer formation would be realized but also the structural characteristics of the polymers. − We have reported previously that the bulky diphenylamino substituent in the (diphenylamino)squarate ligand suppresses polymer formation 3 while the less sterically demanding methyl substituent in methylsquarate facilitates the formation of polymers of diverse structures . We have also observed that the orientation of the substituent to the C 4 -cycle is an important consideration especially with substituents that are attached to it via atoms containing lone pairs of electrons.…”

Section: Introductionmentioning

confidence: 99%

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Attempted Syntheses of Lanthanide(III) Complexes of the Anisole- and Anilinosquarate Ligands

Piggot¹,

Hall²,

White³

et al. 2003

Inorg. Chem.

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The polymeric lanthanide complexes (Ln(mu-CH3OC6H5C4O3)(CH3OC6H5C4O3)2 (H2O)4.xH2O)n [Ln=La (1), Eu (2), Gd (3)], formed from the reaction of aqueous solutions of anisolesquarate and Ln(NO3)3.xH2O, are all structurally similar with only subtle differences between the lanthanum complex and the isomorphous pair of europium and gadolinium analogues. The lanthanum atom in 1 has a square antiprismatic coordination geometry comprising two pendant and two mu-1,3-bridging anisolesquarate groups and four aqua ligands. Complexes 2 and 3 have two independent metal atoms in their asymmetric units compared to one for the lanthanum complex. However, the gross structures of 1-3 are essentially the same. The asymmetric unit of the terbium complex ((CH3OC6H5C4O3)3Tb(H2O)4(mu-CH3OC6H5C4O3)(CH3OC6H5C4O3)2Tb(H2O)5).H2O (4) contains two independent binuclear units which hydrogen bond to form an extended structure very similar to those of 1-3. The ionic polymers ([Ln(mu2-C4O4)(H2O)6][C6H5NHC4O3].4H2O)n [Ln=Eu (5), Gd (6), Tb (7)] result from the incomplete hydrolysis of the anilinosquarate ion during the attempted synthesis of Eu(III), Gd(III), and Tb(III) anilinosquarate complexes. However, complete hydrolysis of the substituent is accomplished by La(III) ions, and the neutral polymer (La2(mu2-C4O4)2(mu3-C4O4)(H2O)11.2H2O)n (8) is formed. In complexes 5-7, the central lanthanide atom has a square antiprismatic geometry, being bonded to two mu-1,2-bridging squarate and six aqua ligands. Two anilinosquarate counteranions participate in second-sphere coordination via direct hydrogen bonding to aqua ligands on each metal center. These counteranions, and the included waters of crystallization, serve to link neighboring cationic polymer chains via an extensive array of O-H...O hydrogen bonds to form a 3-dimensional network. The polymeric lanthanum complex 8 contains two different metal environments, each having distorted monocapped square antiprismatic geometry. For one lanthanum atom the coordination polyhedron comprises five aqua and four squarate ligands, while for the other the polyhedron consists of six aqua and three squarate ligands; in each case one of the aqua ligands occupies the capping position. The squarate ligand exhibits two coordination modes in 8 (mu-1,2- and mu-1,3-bridging), and neighboring polymer chains are cross-linked by hydrogen bonds to form a 3-dimensional network.

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Synthesis of Metal Enolato Complexes

Vicente

2010

Patai's Chemistry of Functional Groups

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Introduction Synthesis from Ketones, Aldehydes and Esters Synthesis from Ketenes, Isocyanates and Acyl Halides Synthesis from Carbon Monoxide and Carbonyl Complexes Synthesis via Cleavage of Ethers and Related Compounds Synthesis from Oxo, Hydroxo or Alkoxo Complexes Oxygenation Reactions Miscellaneous Reactions Acknowledgments

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The complexing properties of the phenylsquarate ligand with Ru(II), Pt(II), Gd(III) and Tb(III) ions

Cited by 10 publications

References 26 publications

Synthesis, Structure, and Magnetochemical Analysis of Selected First-Row Transition-Metal Anilino- and Anisolesquarate Compounds

Synthesis, Structure, and Magnetochemical Analysis of Selected First-Row Transition-Metal Anilino- and Anisolesquarate Compounds

Attempted Syntheses of Lanthanide(III) Complexes of the Anisole- and Anilinosquarate Ligands

Synthesis of Metal Enolato Complexes

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