NMR investigation of intramolecular dynamics of heteroleptic triple-decker (porphyrinato)(phthalocyaninato) lanthanides

Intramolecular dynamics of meso-aryl substituents of porphyrin deck in the triple-decker lanthanide (porphyrinato)(phthalocyaninates) of symmetrical type [Br(4)TPP]Ln[(15C5)(4)Pc]Ln[Br(4)TPP] (Ln = La, Nd, Eu; [Br(4)TPP] = tetrakis-5,10,15,20-(4-bromophenyl)-porphyrinato-ligand; [(15C5)(4)Pc] = tetrakis-(15-crown-5)-phthalocyaninato-ligand) are investigated. Attempts to achieve coalescence were not successful, although the trend of exchanging protons to coalescence point was observed in the case of Nd and Eu complexes. The analysis of NOESY cross-peaks between exchanging protons allowed to evaluate the rotation rate constants at different temperatures. The activation barrier of the meso-aryl substituent rotation was calculated with Arrhenius equation based on determined rate constants. The rate constants are lower and activation barriers are higher than ones found previously for related compounds.     

Ferrocene-decorated (phthalocyaninato)(porphyrinato) double- and triple-decker rare earth complexes: synthesis, structure, and electrochemical properties

A series of four mixed (phthalocyaninato)(porphyrinato) rare earth double-decker complexes (Pc)M[Por(Fc)(2)] [Pc = phthalocyaninate; Por(Fc)(2) = 5,15-di(ferrocenyl)-porphyrinate; M = Eu (1), Y (2), Ho (3), Lu (4)] and their europium(III) triple-decker counterpart (Pc)Eu(Pc)Eu[Por(Fc)(2)] (5), each with two ferrocenyl units at the meso-positions of their porphyrin ligands, have been designed and prepared. The double- and triple-decker complexes 1-5 were characterized by elemental analysis and various spectroscopic methods. The molecular structures of two double-deckers 1 and 4 were also determined by single-crystal X-ray diffraction analysis. Electrochemical studies of these novel sandwich complexes revealed two consecutive ferrocene-based one-electron oxidation waves, suggesting the effective electronic coupling between the two ferrocenyl units. Nevertheless, the separation between the two consecutive ferrocene-based oxidation waves increases from 1 to 4, along with the decrease of rare earth ionic radius, indicating the effect of rare earth size on tuning the coupling between the two ferrocenyl units. Furthermore, the splitting between the two ferrocene-based one-electron oxidations for triple-decker 5 is even smaller than that for 1, showing that the electronic interaction between the two ferrocene centers can also be tuned through changing the linking sandwich framework from double-decker to triple-decker. For further understanding of the electronic coupling between ferrocenyl groups, DFT calculation is carried out to clarify the electronic delocalization and the molecular orbital distribution in these double-decker complexes.     

Efficient scrambling-free synthesis of heteroleptic terbium triple-decker (porphyrinato)(crown-phthalocyaninates)

New heteroleptic triple-decker terbium complexes of general structure [Br(4)TPP]Tb[(15C5)(4)Pc]Tb[Br(4)TPP] (Tb-TD) and [Br(4)TPP]Tb[(15C5)(4)Pc]Tb[(15C5)(4)Pc] (Tb-TD*) (Br(4)TPP = tetrakis-meso-(4-bromophenyl)-porphyrin, (15C5)(4)Pc = tetra-(15-crown-5)-phthalocyanine) are synthesized with 48% and 57% yields, respectively. The triple-decker complexes were prepared by interaction of generated in situ terbium monoporphyrinate [Br(4)TPP]Tb(acac) and corresponding double-decker precursors. The heteroleptic double-decker precursor [Br(4)TPP]Tb[(15C5)(4)Pc] was prepared for the first time in a two step one-pot synthesis. No ligand scrambling was observed in the synthesis of Tb-TD, while 4% scrambling was determined in the case of Tb-TD*. High yields of target triple-decker complexes were achieved despite the presence of electron-donating crown-ether fragments with low thermal stability at the phthalocyanine deck. Analysis of lanthanide-induced paramagnetic shifts of protons of Tb-TD together with data of previously reported La, Pr, Nd and Eu analogues allowed precise separation of contributions of contact and dipolar lanthanide terms as well as verification of isostructurality of complexes within the series.     

Sandwich-type (phthalocyaninato)(porphyrinato) europium triple-decker nanotubes. Effects of the phthalocyanine peripheral substituents on the molecular packing

Three sandwich-type (phthalocyaninato)(porphyrinato) europium triple-decker complexes, namely Eu(2)(Pc)(2)(TClPP) (1), Eu(2)[Pc(β-OC(4)H(9))(8)](2)(TClPP) (2), and Eu(2)[Pc(β-OC(8)H(17))(8)](2)(TClPP) (3), have been designed, synthesized, and fabricated into nanotubes using nanoporous anodized aluminium oxide (AAO) membrane as the template. In particular, the effects of peripheral-substituents at the two phthalocyanine ligands in the triple-decker molecule on the molecular stacking relative to the alumina surface and the molecular packing mode in the nanotubes were clarified on the basis of the scanning electron microscopy (SEM), spectroscopic, and X-ray diffraction results. High-resolution TEM (HRTEM) images, in combination with the electronic absorption and XRD results, indicate that the discotic molecules of 1 without peripheral substituent on the phthalocyanine ligands form columnar structures on the alumina surface with homeotropic molecular stacking depending on the intermolecular π-π interactions in a head-to-tail manner. In good contrast, introduction of eight long octyloxy substituents at the peripheral-positions of the phthalocyanine ligands of 3 induces an increase in the interaction of the triple-decker molecules with the alumina surface, resulting in the formation of nanotubes with discotic molecules of 3 parallel stacking relative to the alumina surface depending on the intermolecular π-π interactions in a face-to-face manner. Most interestingly, introduction of eight shorter length butyloxy substituents at the peripheral-positions of the phthalocyanine ligands of 2 leads to the formation of nanotubes with discotic molecules of 2 parallel stacking relative to the alumina surface but depending on the intermolecular π-π interactions in a head-to-tail manner. X-Ray diffraction (XRD) data confirm the above-mentioned results.     

Optically active mixed (phthalocyaninato)(porphyrinato) rare earth triple-decker complexes. Synthesis, spectroscopy, and effective chiral information transfer

With the view to creating novel sandwich-type tetrapyrrole rare earth complexes toward potential applications in material science and chiral catalysis, two new optically active mixed (phthalocyaninato)(porphyrinato) rare earth triple-decker complexes with both (R)- and (S)-enantiomers [M(2)(Pc)(2)(TCBP)] {TCBP = Meso-tetrakis [3,4-(11,12:13,14-di(1',2'-naphtho)-1,4,7,10,15,18-hexaoxacycloeicosa-2,11,13-triene)-phenyl] porphyrinate; M = Eu (1), Y (2)} have been designed and prepared by treating optically active metal free porphyrin (R)-/(S)-H(2)TCBP with M(Pc)(2) in the presence of corresponding M(acac)(3)·nH(2)O (acac = acetylacetonate) in refluxing 1,2,4-trichlorobenzene (TCB). These novel mixed ring rare earth triple-decker compounds were characterized by a wide range of spectroscopic methods including MS, (1)H NMR, IR, electronic absorption, and magnetic circular-dichroism (MCD) spectroscopic measurements in addition to elemental analysis. Perfect mirror image relationship was observed in the Soret and Q absorption regions in the circular-dichroism (CD) spectra of the (R)- and (S)-enantiomers, indicating the optically active nature of these two mixed (phthalocyaninato)(porphyrinato) rare earth triple-decker complexes. This result reveals the effective chiral information transfer from the peripheral chiral binaphthyl units to the porphyrin and phthalocyanine chromophores in the triple-decker molecule because of the intense π-π interaction between porphyrin and phthalocyanine rings. In addition, their electrochemical properties have also been investigated by cyclic voltammetry (CV).     

Mixed (phthalocyaninato)(porphyrinato) heterometal complexes with sandwich quadruple-decker molecular structure

Two novel mixed (phthalocyaninato)(porphyrinato) rare-earth and cadmium heterometal complexes have been fabricated in one-pot reaction and their sandwich quadruple-decker nature is unambiguously revealed by X-ray single crystal analysis.     

Twist angle perturbation on mixed (phthalocyaninato)(porphyrinato) dysprosium(III) double-decker SMMs

Correlation between molecular structures and slow relaxation of magnetization of three mixed (phthalocyaninato)(porphyrinato) dysprosium(III) double-deckers clearly reveals the effect of the sandwich-type molecular structure, in particular the twist angle, on the quantum tunneling (QT) at zero dc field of these complexes, providing the first direct evidence to the theoretical inference.     

Vibrational spectra of mixed (phthalocyaninato)(porphyrinato) yttrium(III) double-decker complexes: Density functional theory calculations

The vibrational (IR and Raman) spectra of neutral and reduced mixed (phthalocyaninato)(porphyrinato) yttrium(III) double-decker complexes Y(Pc)(Por) and [Y(Pc)(Por)]⁻ [the simplified models of mixed (phthalocyaninato)(porphyrinato) rare earth(III) complexes] are studied using density functional theory (DFT) calculations. The simulated IR and Raman spectra of Y(Pc)(Por) are compared with the experimental IR spectrum of Tb(Pc)(TClPP) and Raman spectrum of Y(Pc)(TClPP), respectively, and many bands can acceptably fit in spite of the different species. On the basis of comparison with the simulated spectra of PbPc and PbPor together with the assistance of normal coordinate analysis, the calculated frequencies in their IR and Raman spectra are identified in terms of the vibrational mode of different ligand for the first time. The calculated frequency at 1048 cm⁻¹ in the IR spectrum of [Y(Pc)(Por)]⁻ with contribution from both Pc and Por vibrational modes is the characteristic IR vibrational mode of the reduced double-decker, while the characteristic IR vibrational mode of Y(Pc)(Por) attributed from the vibration of phthalocyanine monoanion radical Pc⁻ appears at 1257 cm⁻¹. In line with our previous experimental findings that the Raman spectra of M(Pc)(TPP) and M(Pc)(TClPP) are dominated by the Pc vibrational modes, theoretical calculations indicate that most of the Raman vibrational modes contributed from Por ring are covered up by those of Pc ring and thus are hard to be recognized in the Raman spectra of [Y(Pc)(Por)]⁻ and Y(Pc)(Por) due to their much weaker intensity in comparison with that of Pc ligand. Comparison in the IR and Raman spectra between [Y(Pc)(Por)]⁻ and Y(Pc)(Por) also suggests the localization of hole on the Pc ring in the neutral double-decker Y(Pc)(Por). The present work, representing the first detailed DFT study on the vibrational spectra of mixed (phthalocyaninato)(porphyrinato) rare earth(III) double-decker complexes, is useful in helping to understand the vibrational spectroscopic properties of this series of mixed tetrapyrrole ring complexes.     

NMR‐based analysis of structure of heteroleptic triple‐decker (phthalocyaninato) (porphyrinato) lanthanides in solutions

A novel approach for the structural analysis of heteroleptic triple‐decker (porphyrinato)(phthalocyaninato) lanthanides(III) in solutions is developed. The developed approach consists in molecular mechanics (MM+) optimization of the geometry of the complex taking into account the lanthanide‐induced shift (LIS) datasets. LISs of the resonance peaks in ¹H NMR spectra of a series of symmetric complexes [An₄P]Ln[(15C5)₄Pc]Ln[An₄P], where An₄P^2? is 5,10,15,20‐tetrakis(4‐methoxyphenyl)porphyrinato‐dianion, [(15C5)₄Pc]^2? is 2,3,9,10,16,17,24,25‐tetrakis(15‐crown‐5)phthalocyaninato‐dianion and Ln = La, Ce, Pr, Nd, Sm, Eu, are analyzed. Analysis of LISs showed two sets of protons in the molecule with opposite signs of shift. Two‐nuclei analysis of LISs testifies isostructurality of the whole series of investigated complexes in solution despite contraction of the lanthanide ions. Model‐free separation of contact and dipolar contributions of LISs was performed with one‐nucleus technique and did not show changes in contact and dipolar terms within the investigated series. MM+ optimization of the molecular structure allowed the interpretation of features of LIS for each particular group of protons. Parameterization of MM + ‐optimized model of molecule with values of structure‐dependent dipolar contributions of LIS allows the development of the precise structural model of the triple‐decker complex in solution. This approach allows the determination of the geometry and structure of the sandwich macrocyclic tetrapyrrolic complexes together with conformational analysis of flexible peripheral substituents in solutions. The developed method can be applied with minor modifications for the determination of structural parameters of other types of lanthanides(III) complexes with tetrapyrrolic ligands and also supramolecular systems based on them. Copyright © 2010 John Wiley & Sons, Ltd.     

Controlling the nature of mixed (phthalocyaninato)(porphyrinato) rare-earth(III) double-decker complexes: the effects of nonperipheral alkoxy substitution of the phthalocyanine ligand

The half-sandwich rare-earth complexes [M(III)(acac)(TClPP)] (M = Sm, Eu, Y; TClPP = meso-tetrakis(4-chlorophenyl)porphyrinate; acac = acetylacetonate), generated in situ from [M(acac)3] x n H2O and H2(TClPP), were treated with 1,8,15,22-tetrakis(3-pentyloxy)phthalocyanine [H2{Pc(alpha-OC5H11)4}] (Pc = phthalocyaninate) under reflux in n-octanol to yield both the neutral nonprotonated and protonated (phthalocyaninato)(porphyrinato) rare-earth double-decker complexes, [M(III){Pc(alpha-OC5H11)4}(TClPP)] (1-3) and [M(III)H{Pc(alpha-OC5H11)4}(TClPP)] (4-6), respectively. In contrast, reaction of [Y(III)(acac)(TClPP)] with 1,4,8,11,15,18,22,25-octakis(1-butyloxy)phthalocyanine [H2Pc(alpha-OC4H9)8] gave only the protonated double-decker complex [Y(III)H{Pc(alpha-OC4H9)8}(TClPP)] (7). These observations clearly show the importance of the number and positions of substituents on the phthalocyanine ligand in controlling the nature of the (phthalocyaninato)(porphyrinato) rare-earth double-deckers obtained. In particular, alpha-alkoxylation of the phthalocyanine ligand is found to stabilize the protonated form, a fact supported by molecular-orbital calculations. A combination of mass spectrometry, NMR, UV-visible, near-IR, MCD, and IR spectroscopy, and X-ray diffraction analyses, facilitated the differentiation of the newly prepared neutral nonprotonated and protonated double-decker complexes. The crystal structure of the protonated form has been determined for the first time.     

Location of the hole and acid proton in neutral nonprotonated and protonated mixed (phthalocyaninato)(porphyrinato) yttrium double-decker complexes: density functional theory calculations

The location of the hole and acid proton in neutral nonprotonated and protonated mixed (phthalocyaninato)(porphyrinato) yttrium double-decker complexes, respectively, is studied on the basis of density functional theory (DFT) calculations on the molecular structures, molecular orbitals, atomic charges, and electronic absorption and infrared spectra of the neutral, reduced, and two possible protonated species of a mixed (phthalocyaninato)(porphyrinato) yttrium compound: [(Pc)Y(Por)], [(Pc)Y(Por)]-, [(HPc)Y(Por)], and [(Pc)Y(HPor)], respectively. When the neutral [(Pc)Y(Por)] is reduced to [(Pc)Y(Por)]-, the calculated results on the molecular structure, atomic charge, and electronic absorption and infrared spectra show that the added electron has more influence on the Pc ring than on its Por counterpart, suggesting that the location of the hole is on the Pc ring in neutral [(Pc)Y(Por)]. Nevertheless, comparison of the calculation results on the structure, orbital composition, charge distribution, and electronic absorption and infrared spectra between [(HPc)Y(Por)] and [(Pc)Y(HPor)] leads to the conclusion that the acid proton in the protonated mixed (phthalocyaninato)(porphyrinato) yttrium compound should be localized on the Por ring rather than the Pc ring, despite the localization of the hole on the Pc ring in [(Pc)Y(Por)]. This result is in line with the trend revealed by comparative studies of the X-ray single-crystal molecular structures between [MIII{Pc(alpha-OC5H11)4}(TClPP)] and [M(III)H{Pc(alpha-OC5H11)4}(TClPP)] (H2TClPP=5,10,15,20-tetrakis(4-chlorophenyl)porphyrin; M=Sm, Eu). The present work not only represents the first systemic DFT study on the structures and properties of mixed (phthalocyaninato)(porphyrinato) yttrium double-decker complexes, but more importantly sheds further light on the nature of protonated bis(tetrapyrrole) rare-earth complexes.     

Morphology controlled self-assembled nanostructures of sandwich mixed (phthalocyaninato)(porphyrinato) europium triple-deckers. Effect of hydrogen bonding on tuning the intermolecular interaction

A series of five novel sandwich-type mixed (phthalocyaninato)(porphyrinato) europium triple-decker complexes with different numbers of hydroxyl groups at the meso-substituted phenyl groups of porphyrin ligand 1-5 have been designed, synthesized, and characterized. Their self-assembly properties, in particular the effects of the number and positions of hydroxyl groups on the morphology of self-assembled nanostructures of these triple-decker complexes, have been comparatively and systematically studied. Competition and cooperation between the intermolecular pi-pi interaction and hydrogen bonding in the direction perpendicular to the pi-pi interaction direction for different compounds were revealed to result in nanostructures with a different morphology from nanoleafs for 1, nanoribbons for 2, nanosheets for 3, and curved nanosheets for 4 and to spherical shapes for 5. The IR and X-ray diffraction (XRD) results reveal that, in the nanostructures of triple-decker 2 as well as 3-5, a dimeric supramolecular structure was formed through an intermolecular hydrogen bond between two triple-decker molecules, which as the building block self-assembles into the target nanostructures. Electronic absorption spectroscopic results on the self-assembled nanostructures reveal the H-aggregate nature in the nanoleafs and nanoribbons formed from triple-deckers 1 and 2 due to the dominant pi-pi intermolecular interaction between triple-decker molecules, but the J-aggregate nature in the curved nanosheets and spherical shapes of 4 and 5 depending on the dominant hydrogen bonding interaction in cooperation with pi-pi interaction among the triple-decker molecules. Electronic absorption and XRD investigation clearly reveal the decrease in the pi-pi interaction and increase in the hydrogen bonding interaction among triple-decker molecules in the nanostructures along with the increase of hydroxyl number in the order of 1-5. The present result appears to represent the first effort toward realization of controlling and tuning the morphology of self-assembled nanostructures of sandwich tetrapyrrole rare earth complexes through molecular design and synthesis.     

Sandwich-type mixed (phthalocyaninato)(porphyrinato) rare earth double-decker complexes with decreased molecular symmetry of Cs: single crystal structure and self-assembled nano-structure

Two novel sandwich-type mixed (phthalocyaninato)(porphyrinato) rare earth double-decker complexes with decreased molecular symmetry of Cs M(Pc)[D(NHC(8)H(17))(2)PP] [M = Eu, Lu; Pc = unsubstituted phthalocyaninate; D(NHC(8)H(17))(2)PP = 5,10-di(phenyl)-15,20-di(4-octylamino-phenyl)porphyrinate] (1, 2) have been designed, prepared, and characterized. The single crystal and molecular structure of the Eu analogue has been determined by X-ray diffraction analysis, revealing the head-to-tail supramolecular chains formed from closely bound double-decker molecules depending on the N-H-N hydrogen bonds between one octyl-substituted amidocyanogen group attached at the p-position of meso-attached phenyl group of the porphyrin ligand in the mixed ring double-decker molecule and one aza-nitrogen atom of the phthalocyanine ring in the neighboring double-decker molecule in a zigzag form. Their self-assembled nano-structures have been investigated by transmission electronic microscopy (TEM) and scanning electronic microscopy (SEM). Intermolecular H-N-H hydrogen bonding interaction leads to the formation of nano-structures with fusiform morphology with 220-250 nm average width and about 10 μm length for 1 and 300 nm width and 3-5 μm length for 2, respectively, revealing the effect of molecular size in the direction perpendicular to the tetrapyrrole ring on the dimensions of self-assembled nano-structures.     

Arrangement of tris(phthalocyaninato) gadolinium triple-decker complexes with multi-octyloxy groups on water surface

A series of five carefully designed tris(phthalocyaninato) gadolinium triple-decker complexes [Pc(R)8]Gd[Pc(R')8]Gd[Pc(R')8] (R=R'=R'=H; R=R'=H, R'=OC8H17; R=R'=H, R'=OC8H17; R=H, R'=R'=OC8H17; R=R'=R'=OC8H17) (1-5) were prepared and the film forming properties on water surface were systematically investigated. The limited mean molecular area obtained by pi-A isotherms revealed an "edge-on" conformation for all these compounds. UV-vis absorption spectra showed red-shifted Q bands, indicating the formation of J aggregates and effective intermolecular interaction in solid film. Phthalocyanine rings were found to take tilted orientation with respect to the normal of substrate according to the polarized absorption spectroscopic measurements. Low angle X-ray diffraction results provide direct evidence and therefore clearly clarify the point, for the first time, that unsymmetrical triple-decker molecules pack on the water surface with the unsubstituted phthalocyanine ring set close to the water surface and the substituted phthalocyanine ligand with octyloxy groups lies on the top.     

The effects of substituents,molecular symmetry,ionic radius of the rare earth metal,and macrocycle on the electronic absorption spectra characteristics of sandwich-type bis(phthalocyaninato) and mixed (phthalocyaninato)(porphyrinato) rare earth complexes

The electronic absorption spectroscopic data for two series of 60 unsubstituted/substituted bis(phthalocyaninato) and mixed [tetrakis(4-chlorophenyl)porphyrinato](phthalocyaninato) rare earth complexes M(Pc)₂, M(Pc^∗)₂ and M(TClPP)(Pc) [M = Y, La…Lu except Pm; Pc^∗ = dianion of 2,3,9,10,16,17,23,24-octakis(4-methoxyphenoxy)phthalocyanine [Pc(MeOPhO)₈], dianion of 3(4),12(13),21(22),30(31)-tetra(tert-butyl)phthalocyanine (TBPc) and TClPP = tetra(4-chloro)phenylporphyrin] have been measured in CHCl₃. In this paper, the influence of the symmetry of macrocycle rare earth molecules, the effects of ionic radius of the rare earth metal and the influence of substituent species (tert-butyl and 4-methoxyphenoxy groups) onto the peripheral benzene rings on the electronic absorption characteristics of sandwich-type compounds have also been tentatively studied in detail.     

Metal-cation-mediated nanocrystal arrays of sandwich-type (phthalocyaninato) [tetrakis(4-pyridyl)porphyrinato] cerium complex formed at the water-chloroform interface

Regular square, wirelike, quadrate, and rodlike nanocrystal arrays of Cd2+, Hg2+, or Ag+ metal-cation-mediated sandwich-type mixed (phthalocyaninato) [5,10,15,20-tetrakis(4-pyridyl)poprhyrinato] cerium(III) double-decker complex Ce(Pc)(TPyP) have been successfully prepared at the water-chloroform interface. The nanocrystal growth processes were monitored by transmission electron microscopy (TEM), which reveals that different morphologies of nanocrystals have been fabricated from double-decker molecules connected by different kinds of metal cations, forming coordination polymers. These nanoscaled coordination polymers were characterized by FT-IR spectra and energy-dispersive X-ray spectra (EDS). EDS results clearly revealed the elements of the nanocrystals and the FT-IR spectra give evidence for the coordination interaction between the double-decker molecules and metal cations. The UV-vis absorption spectrum indicates the formation of J-aggregates of the double-decker molecules in the nanocrystals formed.     

Vibrational spectroscopy of phthalocyanine and naphthalocyanine in sandwich-type (na)phthalocyaninato and porphyrinato rare earth complexes. Part 15: The IR characteristics of phthalocyanine in homoleptic tetrakis(phthalocyaninato) rare earth(III)-cadmium(II) quadruple-deckers

The infra-red (IR) spectroscopic data for a series of twelve sandwich-type homoleptic tetrakis[2,3,9,10,16,17,23,24-octa(octyloxy)phthalocyaninato] rare earth(III)-cadmium(II) quadruple-decker complexes [Pc(OC₈H₁₇)₈]M[Pc(OC₈H₁₇)₈]Cd[Pc(OC₈H₁₇)₈]M[Pc(OC₈H₁₇)₈] (M = Y, Pr–Yb except Pm) have been collected with resolution of 2 cm⁻¹ and their interpretation in terms tried by analogy with the IR characteristics of bis(phthalocyaninato) cerium double-decker [Pc(OC₈H₁₇)₈]Ce[Pc(OC₈H₁₇)₈] in which the macrocyclic ligands exist as the phthalocyanine dianion. Similar to the bis/tris(phthalocyaninato) rare earth sandwich counterparts, all the absorptions contributed primarily by or at least containing contribution from the vibrations of pyrrole or isoindole stretching, breathing or deformation or aza stretching in the IR spectra of these quadruple-decker compounds show dependent nature on the rare earth ionic size. The shift toward higher energy direction in the frequencies of these vibrations along with the decrease of the rare earth radii reveals the effective and increasing π–π interactions in these quadruple-decker sandwich compounds in the same order. Nevertheless, the decreased sensitivity of the frequencies of the above mentioned vibration modes in particular the weak absorption band due to the isoindole stretching at 1414–1416 cm⁻¹ for the quadruple-decker on rare earth metal size in comparison with corresponding band for bis(phthalocyaninato) rare earth counterparts indicates the relatively weaker π–π interaction in these quadruple-deckers than in the double-deckers.     

Effect of peripheral hydrophobic alkoxy substitution on the organic field effect transistor performance of amphiphilic tris(phthalocyaninato) europium triple-decker complexes

A series of four amphiphilic heteroleptic tris(phthalocyaninato) europium complexes with different lengths of hydrophobic alkoxy substituents on one outer phthalocyanine ligand [Pc(15C5)4]Eu[Pc(15C5)4]Eu[Pc(OCnH(2n+1))8] (n = 4, 6, 10,12) (1, 2, 4, and 5) was designed and prepared. Their film forming and organic field effect transistor properties have been systematically studied in comparison with analogous [Pc(15C5)4]Eu[Pc(15C5)4]Eu[Pc(OC8H17)8] (3). Experimental results showed that all these typical amphiphilic sandwich triple-decker molecules have been fabricated into highly ordered films by the Langmuir-Blodgett (LB) technique, which displays carrier mobility in the direction parallel to the aromatic phthalocyanine rings in the range of 0.0032-0.60 cm2 V(-1) s(-1) depending on the length of the hydrophobic alkoxy substituents. This is rationalized on the basis of comparative morphology analysis results of the LB films by the atomic force microscopy technique.     

The synthesis of cyclopentadiene derivatives of lanthanides by the reaction of dicyclopentadienyl-mercury with lanthanides(o)

The interaction of (C₅H₅)₂Hg with activated Ln^o, where Ln  La, Sm, Eu, Tm, Yb, in THF was shown to give either divalent or trivalent cyclopentadienyl derivatives of these metals, depending on the reaction conditions and re-agents ratio.     

Synthesis and Crystal Structure of a Mixed （Phthalocyaninato）（porphyrinato） Yttrium Double-decker Complex

The title compound,a mixed(phthalocyaninato)(porphyrinato) yttrium double-decker complex 1,has been synthesized and structurally characterized by X-ray single-crystal diffraction method.Crystal data:monoclinic,space group C2/c,Z = 8,C79H52Cl10N12O4Y,Mr = 1676.74,a = 38.217(3),b = 18.9867(13),c = 26.200(3) ,β = 128.0190(10)°,V = 14977(2) 3,Dc = 1.487 g/cm3,μ(MoKα) = 1.196 mm-1,F(000) = 6808,R = 0.0745 and wR = 0.2208 for observed reflections with I > 2σ(I).X-ray analysis reveals that the coordination polyhedron adopts a slightly distorted square-antiprismatic structure around the metal center.Both phthalocyanine and porphyrin ligands are saucer-shaped,with the skew angle of the two ligand planes approximately 45°.