Thermotropic Mesomorphism in Some Cu(II) and Pd(II) Metallorganic Complexes

Caruso, Ugo; Roviello, Antonio; Sirigu, Augusto

doi:10.1080/02678298808086691

Cited by 46 publications

(5 citation statements)

References 9 publications

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“…Bis(salicylaldimine)copper(II) Complexes 3. Salicylaldimine complexes of the type 3 have been investigated by many groups, − and a large number of compounds with alkyl, alkyloxy, and especially alkyloxybenzoyloxy substituents have been reported. Our series of complexes (Table 2) completes this class of substances.…”

Section: Resultsmentioning

confidence: 99%

Synthesis and Mesogenic Properties of Binuclear Copper(II) Complexes Derived from Salicylaldimine Schiff Bases

et al. 2003

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The synthesis and mesomorphic (liquid crystal) properties of new binuclear dihalocopper(II) complexes derived from N- and ring-substituted salicylaldimine Schiff bases are reported, together with the mesomorphic properties of their monomeric precursor complexes. With just N-substituents both the dichlorodicopper(II) binuclear complexes and their mononuclear analogues are waxy solids with melting points that increase with their N-chain length. However, with both N- and ring-substituents in the 4-positions, the mononuclear and binuclear complexes are each liquid crystalline or mesogenic, except in case of the mononuclear complexes where the N-substituent is straight chain alkyl. The other mononuclear complexes exhibit a variety of liquid crystal phases: smectic A, C, and E (SA, SC, and SE, respectively). The liquid crystal phase SA is observed in the binuclears with shorter chain N-substituents p-R-O-C6H4- and shorter chain ring-substituents. The chain lengths were increased until the phase behavior expanded to a further form SC in the case of an N-substituent p-C14H29O-C6H4- and a -OC12H25 ring substituent. This points the way toward achieving multiphase behavior with these binuclear systems. The Cu-Br analogues of the binuclear complexes behave similarly but with significant qualitative differences, specifically lower mesophase stability and higher melting temperatures. The structures of the nonmesogenic binuclears ([Cu(N-dodecylSal)X]2, X=Cl, Br) were determined with the aid of X-ray crystallography. These are prototypes for the structures of the binuclear complexes and especially for the shape of the central Cu2O2 X2 core in the binuclears: distorted planar coordination about the copper with distortion toward tetrahedral measured by a characteristic twist angle tau (0 degrees planar; 90 degrees tetrahedral). The binuclear complexes also show magnetic coupling which can be used to estimate the geometry. For [Cu(N-dodecylSal)X]2 tau>36 degrees, which corresponds to weaker coupling than observed in the mesogenic binuclears where a stronger magnetic coupling indicates a geometry closer to planar (tau=25 degrees). The mesophases were characterized by differential scanning calorimetry (DSC) analysis and optical polarized microscopy.

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Section: Resultsmentioning

confidence: 99%

Synthesis and Mesogenic Properties of Binuclear Copper(II) Complexes Derived from Salicylaldimine Schiff Bases

et al. 2003

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“…In the field of coordination chemistry, this type of ortho hydroxylated Schiff bases has received an overwhelming attention particularly on the study of complex formation [26][27][28][29].…”

Section: Introductionmentioning

confidence: 99%

Ab initio HF and DFT calculations on an organic non-linear optical material

2009

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The molecular geometric optimization, vibrational frequencies, and gauge-including atomic orbital (GIAO) 1 H and 13 C chemical shift values of 3-[(1E)-N-ethylethanimidoyl]-4-hydroxy-6-methyl-2H-pyran-2-one have been investigated by using ab initio Hartree-Fock (HF) and density functional method (B3LYP: Becke-3-Lee-Yang-Parr) with 6-31G(d) and 6-31??G(d,p) basis sets. Also, the first hyperpolarizabilities have been calculated at the HF and B3LYP levels employing the corresponding basis sets. To understand this phenomenon in the context of molecular orbital picture, we examined the molecular HOMOs and molecular LUMOs generated via HF and B3LYP levels. The computed vibrational frequencies are used to determine the types of molecular motions associated with each of the experimental bands observed. Data of 3-[(1E)-N-ethylethanimidoyl]-4-hydroxy-6-methyl-2H-pyran-2-one display significant second-order molecular nonlinearity and provide the basis for design of efficient nonlinear optical materials.

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“…Moreover, palladium(II) complexes exhibit higher melting and isotropization temperature than the corresponding copper(II) complex. This feature is commonly observed [23,24] and might be related to the higher stability of Pd(II) complexes towards a pseudo-tetrahedral distortion of square-planar coordinative geometry. Fig.…”

Section: Introductionmentioning

confidence: 94%

“…Within this field relevant interest has been devoted to liquid crystalline coordination complexes of palladium(II) and copper(II) [14,15]. However, metallomesogens derived from heterocyclic containing ligands, although worth of interest, are relatively rare [16][17][18].…”

Section: Introductionmentioning

confidence: 99%