Pyrazole-based allylpalladium complexes: Supramolecular architecture and liquid crystal behaviour

Torralba, M. Carmen; Cano, Mercedes; Campo, José A.; Heras, J.V.; Pinilla, Elena; Torres, M. Rosario

doi:10.1016/j.inoche.2006.07.043

Cited by 17 publications

(8 citation statements)

References 14 publications

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“…The 3-(4-alkyloxyphenyl)-1H-pyrazoles (Hpz R(n) ) and 3,5-bis(4-alkyloxyphenyl)-1H-pyrazoles (Hpz 2R(n) ) (R = C 6 H 4 OC n H 2n+1 ; n = 1, 12, 14, 16, 18) were prepared by procedures described in previous work. 31,32 Commercial solvents were dried prior to use.…”

Section: Experimental Materials and Physical Measurementsmentioning

confidence: 99%

Silver pyrazole complexes with tunable liquid crystals and luminescent properties

et al. 2010

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Section: Experimental Materials and Physical Measurementsmentioning

confidence: 99%

Silver pyrazole complexes with tunable liquid crystals and luminescent properties

et al. 2010

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“…The 3-(4-alkyloxyphenyl)-1H-pyrazoles (Hpz R(n) ) and 3,5-bis(4-alkyloxyphenyl)-1H-pyrazoles (Hpz 2R(n) ) (R = C 6 H 4 OC n H 2n + 1 ; n = 4, 12, 14, 16, 18) and the starting Au complex [AuCl(tht)] (tht = tetrahydrothiophene) were prepared by procedures described in previous works. 19,20,26 Commercial solvents were dried prior to use. Elemental analyses for carbon, hydrogen and nitrogen were carried out by the Microanalytical Service of Complutense University.…”

Section: Experimental Materials and Physical Measurementsmentioning

confidence: 99%

“…We have proved that, independent of the mesomorphic nature of the 3,5-disubstituted pyrazoles Hpz 2R(n) or the non-mesomorphism of the 3-substituted ligands Hpz R(n) (Hpz 2R(n) = 3,5-bis(4-alkyloxyphenyl)pyrazole; Hpz R(n) = 3-(4alkyloxyphenyl)pyrazole), both were able to induce mesomorphism upon coordination to several metal fragments. 19,20 So the coordination of the non-mesomorphic Hpz R (12) ligand to the AuCl fragment gave rise to the complex [AuCl(Hpz R (12) )] which, in addition to the liquid crystal behaviour, exhibited luminescent properties. 9 On the other hand, we have also recently reported the crystal structure of the related luminescent compounds containing the disubstituted pyrazole with shorter alkyl chains (n = 4), [Ag(Hpz 2R(4) ) 2 ][BF 4 ] and [Au(Hpz 2R (4) ) 2 ][O 3 S-C 6 H 4 -p-CH 3 ], both exhibiting an unconventional 'H' shape (Fig.…”

Section: Introductionmentioning

confidence: 99%

Silver and gold luminescent metallomesogens based on pyrazole ligands

et al. 2008

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A series of ionic bis(pyrazole)-silver(I) and -gold(I) complexes [ML(2)][A] (M = Ag, Au; A = BF(4)(-), PF(6)(-), NO(3)(-)), prepared by coordination of the mesomorphic L = Hpz(2R(n)) or non-mesomorphic L = Hpz(R(n)) pyrazole ligands (Hpz(2R(n)) = 3,5-bis(4-alkyloxyphenyl)pyrazole; Hpz(R(n)) = 3-(4-alkyloxyphenyl)pyrazole), has been studied. The complexes exhibit enantiotropic behaviour, showing smectic A (SmA) mesophases. The choice of the ligands allows the achievement of 'H' or 'U' molecular shapes, which appear to be responsible for the attainment of liquid crystal mesophases, these not being dependent on the coordinating or non-coordinating nature of the A counteranions. The new complexes are photoluminescent both in the solid state and in solution at room temperature. In addition, the luminescent behaviour of selected compounds as a function of the temperature indicates that the luminescence is maintained in the mesophase.

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“…24 A strategy used in the design of metallomesogens is to incorporate functionalised bridging pyrazolates due to their ability to attain an adequate geometry for achieving mesomorphic properties. In this context, pyrazole and pyrazolate palladium, 25,26 gold [27][28][29] and silver 10,30 complexes have been described as liquid crystal materials with smectic and columnar arrangements.…”

Section: Introductionmentioning

confidence: 99%

Polycatenar pyrazole and pyrazolate ligands as building blocks of new columnar Pd(ii) metallomesogens

et al. 2014

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Dicatenar pyridine-functionalised pyrazole ligands [Hpz(R(n,n)py)] (R(n,n) = C6H3(OCnH2n+1)2, n = 4, 6, 8, 10, 12, 14, 16, 18) have been strategically synthesised to be used as new building blocks for designing discotic liquid crystalline materials. Their coordination to Pd(II) fragments has allowed to achieve two novel families of metallomesogens, [Pd(pz(R(n,n)py))2] () and [PdCl2(Hpz(R(n,n)py))] (), in which the ligand is coordinated in the anionic form as pyrazolate or in the neutral form as pyrazole, respectively. Thermal studies showed that the ligands with n = 14 and 16 carbon atoms, as well as all the palladium complexes, display discotic mesophases in the temperature range of 68-141 °C. The results indicate that the coordination environment around the metal is a determining factor which allows control of the supramolecular arrangement of the mesophase. Disc-like molecules from complexes pack themselves into cylindrical structures that result in hexagonal columnar phases (Colh), while the half-disc shaped molecules from self-assemble into a layer with an antiparallel dimeric disposition which generates lamellar columnar phases (ColL). Schematic models based on X-ray powder diffraction (XRD) experiments are proposed to illustrate the molecular organisation of these Pd metallomesogens in the columnar mesophases.

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Pyrazole-based allylpalladium complexes: Supramolecular architecture and liquid crystal behaviour

Cited by 17 publications

References 14 publications

Silver pyrazole complexes with tunable liquid crystals and luminescent properties

Silver pyrazole complexes with tunable liquid crystals and luminescent properties

Silver and gold luminescent metallomesogens based on pyrazole ligands

Polycatenar pyrazole and pyrazolate ligands as building blocks of new columnar Pd(ii) metallomesogens

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