Synthesis of thiol-derivatized europium porphyrinic triple-decker sandwich complexes for multibit molecular information storage

The storage of multiple bits of information at the molecular level requires molecules with a large number of distinct oxidation states. Lanthanide triple-decker sandwich molecules employing porphyrins and phthalocyanines afford four cationic states and are very attractive for molecular information storage applications. Five triple-decker building blocks have been prepared of the type (phthalocyanine)Eu(phthalocyanine)Eu(porphyrin), each bearing one iodo, one ethyne, or one iodo and one ethyne group attached to the porphyrin unit. Two triple-decker building blocks with different oxidation potentials were derivatized with an S-acetylthiophenyl unit for attachment to an electroactive surface. To explore the preparation of arrays comprised of triple deckers, which may lead to the storage of a larger number of bits, two types of dyads of triple deckers were prepared. An ethyne-linked dyad of triple deckers bearing one S-acetylthiophenyl unit was prepared via repetitive Sonogashira couplings, and a butadiyne-linked dyad was prepared via a modified Glaser coupling. The triple deckers were characterized by absorption spectroscopy, laser-desorption mass spectrometry, and (1)H NMR spectroscopy. The thiol-derivatized triple deckers form self-assembled monolayers (SAMs) on gold via in situ cleavage of the thiol protecting group. The SAM of each array is electrochemically robust and exhibits three well-resolved, reversible oxidation waves. These electrochemical characteristics indicate that these types of molecules are well suited for storing multiple bits of information.     

Constructing sandwich-type rare Earth double-decker complexes with N-confused porphyrinato and phthalocyaninato ligands

Reaction of the half-sandwich complexes M(III)(Pc)(acac) (M = La, Eu, Y, Lu; Pc = phthalocyaninate; acac = acetylacetonate) with the metal-free N-confused 5,10,15,20-tetrakis[(4-tert-butyl)phenyl]porphyrin (H(2)NTBPP) or its N2-position methylated analogue H(CH(3))NTBPP in refluxing 1,2,4-trichlorobenzene (TCB) led to the isolation of M(III)(Pc)(HNTBPP) (M = La, Eu, Y, Lu) or Y(III)(Pc)[(CH(3))NTBPP] in 8-15% yield. These represent the first examples of sandwich-type rare earth complexes with N-confused porphyrinato ligands. The complexes were characterized with various spectroscopic methods and elemental analysis. The molecular structures of four of these double-decker complexes were also determined by single-crystal X-ray diffraction analysis. In each of these complexes, the metal center is octa-coordinated by four isoindole nitrogen atoms of the Pc ligand, three pyrrole nitrogen atoms, and the inverted pyrrole carbon atom of the HNTBPP or (CH(3))NTBPP ligand, forming a distorted coordination square antiprism. For Eu(III)(Pc)(HNTBPP), the two macrocyclic rings are further bound to a CH(3)OH molecule through two hydrogen bonds formed between the hydroxyl group of CH(3)OH and an aza nitrogen atom of the Pc ring or the inverted pyrrole nitrogen atom of the HNTBPP ring, respectively. The location of the acidic proton at the inverted pyrrole nitrogen atom (N2) of the protonated double-deckers was revealed by (1)H NMR spectroscopy.     

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.     

Novel approaches to model-free analysis of lanthanide-induced shifts, targeted to the investigation of contact term behavior

Three novel equations were proposed to perform graphical model-free analysis of lanthanide-induced shifts in NMR spectra of axially symmetrical complexes within Bleaney's T(-2) expansion. Application and efficiency of these newly developed approaches were demonstrated on the example of heteroleptic triple-decker crown-phthalocyaninates (Pc)M[(15C5)(4)Pc]M(Pc), where (15C5)--15-crown-5, (Pc(2-))--phthalocyaninato-dianion, M = Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, Yb and Y as diamagnetic reference. By construction of these equations, the proposed analytical techniques are more sensitive to variations of hyperfine coupling terms throughout lanthanide series, in comparison with previously developed approaches, becoming a valuable tool for the investigation of structural and electronic characteristics of lanthanide complexes.     

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).     

Triple-decker sandwich compounds bearing compact triallyl tripods for molecular information storage applications

The design of redox-active molecules that afford multistate operation and high charge density is essential for molecular information storage applications. Triple-decker sandwich compounds composed of two lanthanide metal ions and three porphyrinic ligands exhibit a large number of oxidation states within a relatively narrow electrochemical window. High charge density requires a small footprint upon tethering triple deckers to an electroactive surface. All triple deckers examined to date for information storage have been tethered via the terminal ligand and have exhibited large footprints (approximately 670 A2). Five new homonuclear (Eu or Ce) triple deckers have been prepared (via statistical or rational methods) to examine the effect of tether attachment site on molecular footprint. Three triple deckers are tethered via the terminal ligand (porphyrin) or central ligand (porphyrin or imidazophthalocyanine), whereas two triple deckers each bear two tethers, one at each terminal ligand. The tether is a compact triallyl tripod. Monolayers of the triple deckers on Si(100) were examined by electrochemical and FTIR techniques. Each triple decker exhibited the expected four resolved voltammetric waves, owing to formation of the mono-, di-, tri-, and tetracations. The electrochemical studies of surface coverage (gamma, obtained by integrating the voltammetric waves) reveal that coverages approaching 10(-10) mol cm(-2), corresponding to a molecular footprint of approximately 170 A2, are readily achieved for all five of the triple deckers. The surface coverage observed for the tripodal functionalized triple deckers is approximately 4-fold higher than that obtained for monopodal-functionalized triple deckers (carbon, oxygen, or sulfur anchor atoms) attached to either Si(100) or Au(111). The fact that similar, relatively high, surface coverages can be achieved regardless of the location (or number) of the tripodal tether indicates that the tripodal functionalization, rather than the location of the tether, is the primary determinant of the packing density.     

Synthesis, characterization, and OFET properties of amphiphilic heteroleptic tris(phthalocyaninato) europium(III) complexes with hydrophilic poly(oxyethylene) substituents

A series of amphiphilic heteroleptic tris(phthalocyaninato) europium complexes with hydrophilic poly(oxyethylene) heads and hydrophobic alkoxy tails {Pc[(OC2H4)2OCH3]8}Eu{Pc[(OC2H4)2OCH3]8}Eu[Pc(OCnH2n + 1)8] (n = 6, 8, 10,12) (1-4) were designed and prepared from the reaction between homoleptic bis(phthalocyaninato) europium compound {Pc[(OC2H4)2OCH3]8}Eu{Pc[(OC2H4)2OCH3]8} and metal-free 2,3,9,10,16,17,23,24-octakis(alkoxy)phthalocyanine H2Pc(OCnH2n + 1)8 (n = 6, 8, 10,12) in the presence of Eu(acac)3.H2O (Hacac = acetylacetone) in boiling 1,2,4-trichlorobenzene (TCB). These novel sandwich triple-decker complexes have been characterized by a wide range of spectroscopic methods and have been electrochemically studied. With the help of the Langmuir-Blodgett (LB) technique, these typical amphiphilic triple-decker complexes have been fabricated into organic field effect transistors (OFET) with an unusual bottom contact configuration. The devices display good OFET performance with the carrier mobility for holes in the direction parallel to the aromatic phthalocyanine rings, which shows dependence on the length of the hydrophobic alkoxy side chains, decreasing from 0.46 for 1 to 0.014 cm2 V(-1) s(-1) for 4 along with the increase in the carbon number in the hydrophobic alkoxy side chains.     

Synthesis and characterization of bis(S-acetylthio)-derivatized europium triple-decker monomers and oligomers

We report the synthesis of monomers, dimers, trimers, and oligomers of triple-decker (TD) complexes bearing S-acetylthio groups at the termini: AcS-(TD)(n)()-SAc. Each TD was of type (Pc)Eu(Pc)Eu(Por), where H(2)Pc = tetra-tert-butylphthalocyanine and H(2)Por is a meso-tetraarylporphyrin bearing functional groups at the 4-aryl position such as ethynyl, TMS-ethynyl, TIPS-ethynyl, or iodo. The TD arrays were prepared by Sonogashira- and Glaser-type coupling reactions, affording 1,4-diphenylethyne or 1,4-diphenylbutadiyne linkers joining the TDs. Each TD array exhibited high solubility in organic solvents such as CHCl(3) or CH(2)Cl(2). Self-assembled monolayers (SAMs) of all the TDs were prepared on Au substrates and investigated via a variety of electrochemical techniques aimed at determining redox potentials, rates of electron transfer under applied potential, and rates of charge retention in the absence of applied potential. The electrochemical measurements were accompanied by ellipsometric studies aimed at determining SAM thickness and, hence, the orientation of the complexes with respect to the surface plane. All of the TD SAMs exhibit robust, reversible voltammetry yielding four well-resolved waves in the potential range of 0 to +1.6 V (corresponding to the mono-, di-, tri-, and tetracations). The electron-transfer rates for the various oxidation states of all of the TD SAMS are similar and in the 10(4)-10(5) s(-)(1) range. The charge-dissipation rates (measured in terms of a charge-retention half-life) are also similar and are in the 10-60 s range. These rates are influenced by both the packing density of the molecules and the orientation of the molecules on the surface. The full body of data supports the view that all of the dithio-derivatized TD complexes assume a similar geometry on the surface. In particular, the complexes are oriented with their linkers/macrocycle planes generally parallel with the surface, unlike monothio-derivatized analogues, which are in a more perpendicular geometry. The parallel geometry of the dithio-derivatized TDs is qualitatively consistent with covalent attachment to Au via both thiols.     

Aggregation behavior of heteroleptic tris(phthalocyaninato) dysprosium complexes with different alkoxy chains in monolayer or multilayer solid films

Three heteroleptic tris(phathlocyaninato) dysprosium triple-decker complexes with different alkoxy groups at the peripheral positions of the medium phthalocyanine ligand (Pc)Dy[Pc(OCnH(2n+1))8]Dy(Pc) (n = 4, 8, 16) (I-III) {Pc = unsubstituted phthalocyaninate; Pc(OC4H9)8 = 2,3,9,10,16,17,23,24-octakis(butyloxy)phthalocyaninate; Pc(OC8H17)8 = 2,3,9,10,16,17,23,24-octakis(octyloxy)phthalocyaninate; Pc(OC16H33)8 = 2,3,9,10,16,17,23,24-octakis(hexadecyloxy)phthalocyaninate} have been synthesized, and their aggregate behaviors in monolayer and multilayer solid films have been comparatively studied. The pure compounds and their 1:4 mixtures with stearic acid (SA) have been found to form a stable monolayer at the air/water interface with a tilted edge-on orientation of (Pc)Dy[Pc(OCnH(2n+1))8]Dy(Pc) molecules. In the pure monolayers of the three triple-decker compounds, wirelike molecular aggregates were observed by high-resolution transmission electron microscopy (HRTEM). Adding SA has been found to prevent triple-decker compounds (Pc)Dy[Pc(OC4H9)8]Dy(Pc) (I) and (Pc)Dy[Pc(OC8H17)8]Dy(Pc) (II) from forming large aggregates, and small domains with a diameter of ca. 10 nm were observed in the mixed monolayers. HRTEM studies revealed that two crystalline phases with rectangular and hexagonal lattice structure are present in the small domains. However, both pi-A isotherms and HRTEM studies indicated that the mixed monolayer of compound (Pc)Dy[Pc(OC16H33)8]Dy(Pc) (III) with SA did not show a difference from the corresponding pure monolayer. The SA molecules were pressed into the cavity above the phthalocyanine ring formed by the eight long hexadecyloxy side chains of the medium macrocycle ligand in III. The multilayer LB films of all of these triple deckers fabricated by the vertical dipping method showed very good layered structure as revealed by the multiple-order diffraction peaks in low-angle X-ray diffraction (LAXRD) patterns.     

Selective one-step synthesis of triple-decker (porphyrinato)(phthalocyaninato) early lanthanides: the balance of concurrent processes

An effective one-step approach for the preparation of (porphyrinato)(phthalocyaninato) early lanthanides of type [Br(4)TPP]Ln[(15C5)(4)Pc]Ln[Br(4)TPP], where Br(4)TPP = 5,10,15,20-tetrakis-(4-bromophenyl)-porphyrinato-ligand, (15C5)(4)Pc = tetrakis-(15-crown-5)-phthalocyaninato-ligand and Ln = La, Pr, Nd or Eu, is developed. The influence of various factors on the reaction pathway and yields of the complexes is investigated in detail. The developed protocol is found to be general for the early lanthanide subgroup. Variation of the synthetic conditions allowed the determination and isolation of possible side-products, namely heteroleptic double-deckers [Br(4)TPP]Ln[(15C5)(4)Pc] (Ln = Nd, Eu) and triple-decker [Br(4)TPP]Nd[(15C5)(4)Pc]Nd[(15C5)(4)Pc]. The peculiarities of the NMR lanthanide-induced shifts (LIS) of resonances of the synthesized triple-decker complexes are precisely investigated. The isostructurality of the synthesized complexes within the series as well as isostructurality with previously synthesized compounds is demonstrated in terms of two-nuclei analysis of LIS.     

Optically active mixed phthalocyaninato-porphyrinato rare-earth double-decker complexes: synthesis, spectroscopy, and solvent-dependent molecular conformations

Reaction between the optically active metal-free phthalocyanine with a pi system with noncentrosymmetrical C(2) [corrected] symmetry ((S)- and (R)-H(2){Pc(OBNP)(2)}; OBNP=binaphthylphthalocyanine) and half-sandwich complexes [M(III)(acac)(TClPP)] (M=Y, Eu; TClPP=meso-tetrakis(4-chlorophenyl)porphyrinate; acac=acetylacetonate), which were generated in situ from [M(acac)(3)].n H(2)O and H(2)(TClPP) in n-octanol at reflux, provided the first optically active protonated mixed phthalocyaninato-porphyrinato rare-earth double-decker complexes [M(III)H{Pc(OBNP)(2)}(TClPP)] (M=Y, Eu) in good yield. In addition to electronic absorption spectroscopy and magnetic circular dichroism results, circular dichroism shows different spectroscopic features of these mixed-ring rare-earth double-decker compounds in different solvents, such as DMF and CHCl(3), which was well-reproduced on the basis of time-dependent density functional theory calculation results for the yttrium species (S)-[Y(III){Pc(OBNP)(2)}(Por)](-) (Por=porphyrinate, which is obtained by removing the four chlorophenyl groups from the TClPP ligand) in terms of the change in the rotation angle between the two macrocyclic ligands in the double-decker molecules. These results revealed the solvent-dependent nature of the molecular conformation of mixed-ring rare-earth double-decker complexes, which suggests a new way of tuning the optical and the electrochemical properties of sandwich-type bis(tetrapyrrole)-metal double-decker complexes in solution by changing the solvent.     

Lanthanide(III) Bis(phthalocyaninato)–[60]Fullerene Dyads: Synthesis,Characterization, and Photophysical Properties

A novel series of double‐decker lanthanide(III) bis(phthalocyaninato)–C₆₀ dyads [Ln^III(Pc)(Pc′)]–C₆₀ (M=Sm, Eu, Lu; Pc=phthalocyanine) ( 1 a – c ) have been synthesized from unsymmetrically functionalized heteroleptic sandwich complexes [Ln^III(Pc)(Pc′)] (Ln=Sm, Eu, Lu) 3 a – c and fulleropyrrolidine carboxylic acid 2 . The sandwich complexes 3 a – c were obtained by means of a stepwise procedure from unsymmetrically substituted free‐base phthalocyanine 5 , which was first transformed into the monophthalocyaninato intermediate [Ln^III(acac)(Pc)] and further reacted with 1,2‐dicyanobenzene in the presence of 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU). ¹H NMR spectra of the bis(phthalocyaninato) complexes 3 a – c and dyads 1 a – c were obtained by adding hydrazine hydrate to solutions of the complexes in [D₇]DMF, a treatment that converts the free radical double‐deckers into the protonated species, that is, [Ln^III(Pc)(Pc′)H] and [Ln^III(Pc)(Pc′)H]–C₆₀. The electronic absorption spectra of 3 a – c and 1 a – c in THF exhibit typical transitions of free‐radical sandwich complexes. In the case of dyads 1 a – c , the spectra display the absorption bands of both constituents, but no evidence of ground‐state interactions could be appreciated. When the UV/Vis spectra of 3 a – c and 1 a – c were recorded in DMF, typical features of the reduced forms were observed. Cyclic voltammetry studies for 3 a – c and 1 a – c were performed in THF. The electrochemical behavior of dyads 1 a – c is almost the exact sum of the behavior of the components, namely the double‐decker [Ln^III(Pc)(Pc′)] and the C₆₀ fullerene, thus confirming the lack of ground‐state interactions between the electroactive units. Photophysical studies on dyads 1 a – c indicate that only after irradiation at 387 nm, which excites both C₆₀ and [Ln^III(Pc)(Pc′)] components, a photoinduced electron transfer from the [Ln^III(Pc)(Pc′)] to C₆₀ occurs.     

Triamidotriazacyclononane complexes of group 3 metals. Synthesis and crystal structures

Reaction of yttrium and lanthanide trichlorides (Ln = La, Eu, Yb) with 1 equiv of the trisodium salt of 1,4,7-tris(dimethylsilylaniline)-1,4,7-triazacyclononane (Na(3)[(SiMe(2)NPh)(3)-tacn](THF)(2)) gives good yields of the compounds [M[(SiMe(2)NPh)(3)-tacn]] (M = Y (1), Eu (3), Yb (4)) and [La[(SiMe(2)NPh)(3)-tacn](THF)] (2). Reduction of 3 with Na/Hg followed by recrystallization in the presence of diglyme yielded crystals of [Eu[(SiMe(2)NPh)(3)-tacn]][Na(diglyme)(2)] (5). Synthesis of the uranium(III) complex [U[(SiMe(2)NPh)(3)-tacn]] (6) is achieved by reaction of 1 equiv of Na(3)[(SiMe(2)NPh)(3)-tacn](THF)(2) with uranium triiodide. The U(IV) complexes, [U[(SiMe(2)NPh)(3)-tacn]X] (X = Cl (7); I (8)), were prepared via oxidation of 6 with benzyl chloride or I(2), but salt metathesis from UCl(4) provided a higher yield route for 7. The solid-state structures of 1-7 were determined by single-crystal X-ray diffraction. The ligand [(SiMe(2)NPh)(3)-tacn] generates a trigonal prismatic coordination environment for the metal center in the neutral complexes 1, 3, 4, and 6 and the ionic 5. In 2 the six nitrogen atoms of the ligand are in a trigonal prismatic configuration with the oxygen atom of the THF capping one of the triangular faces of the trigonal prism. In 7 the coordination geometry around the uranium atom is best described as bicapped trigonal bipyramidal.     

Electron-donating alkoxy-group-driven synthesis of heteroleptic tris(phthalocyaninato) lanthanide(III) triple-deckers with symmetrical molecular structure

Reaction of heteroleptic bis(phthalocyaninato) lanthanide compounds [(Pc)M{Pc(OC8H17)8}] [H2Pc=unsubstituted phthalocyanine; H2Pc(OC8H17)8 = 2,3,9,10,16,17,23,24-octakis(octyloxy)phthalocyanine] with monomeric complexes [(Pc)M(acac)] (Hacac=acetylacetone), both of which generated in situ, led to the isolation of heteroleptic phthalocyaninato-[2,3,9,10,16,17,23,24-octakis(octyloxy)phthalocyaninato] lanthainde(III) triple-decker complexes [(Pc)M{Pc(OC8H17)8}] (M=Gd-Lu) (1-8) as the sole product. Heterodinuclear analogues [(Pc)Lu{Pc(OC8H17)8}M(Pc)] (M=Gd-Yb) (9-15) were obtained in a similar manner from the reaction of [(Pc)M{Pc(OC8H17)8}] (M=Gd-Yb) and [(Pc)Lu(acac)]. The molecular structures of the herterodinuclear compound [(Pc)Lu{Pc(OC8H17)8}Er(Pc)] (13) and its homodinuclear counterparts [(Pc)M{Pc(OC8H17)8}M(Pc)] (M=Er, Lu) (5, 8) have been determined by X-ray diffraction analysis; these structures exhibit a symmetrical molecular structure with one inner planar Pc(OC8H17)8 ligand and two outer domed Pc ligands. In addition to various spectroscopic analyses, the electrochemistry of these compounds has also been studied by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods, revealing the gradually enhanced pi-pi interactions among the phthalocyanine rings in the triple-deckers along with the lanthanide contraction.     

Synthesis, characterization, and DNA-binding and -photocleavage properties of water-soluble lanthanide porphyrinate complexes

A series of cationic lanthanide porphyrinate complexes of the general formula [(Por)Ln(H(2)O)(3)](+) (Ln(3+)=Yb(3+) and Er(3+)) were synthesized in moderate yields through the interaction of meso-pyridyl-substituted porphyrin free bases (H(2)Por) with [Ln{N(SiMe(3))(2)}(3)]·x[LiCl(thf)(3)], and the corresponding neutral derivatives [(Por)Ln(L(OMe))] (L(OMe)(-)=[(η(5)-C(5)H(5))Co{P(=O)(OMe)(2)}(3)](-)) were also prepared from [(Por)Ln(H(2)O)(3)](+) by the addition of the tripodal anion, L(OMe)(-), an effective encapsulating agent for lanthanide ions. Furthermore, the water-soluble lanthanide(III) porphyrinate complexes--including [(cis-DMPyDPP)Yb(H(2)O)(3)]Cl(3) (cis-DMPyDPP=5,10-bis(N-methylpyridinium-4'-y1)-15,20-di(phenyl)porphyrin), [(trans-DMPyDPP)Yb(H(2)O)(3)]Cl(3) (trans-DMPyDPP=5,15-bis(N-methylpyridinium-4'-y1)-10,20-di(phenyl)porphyrin), [(TMPyP)Yb(L(OMe))]I(4), and [(TMPyP)Er(L(OMe))]I(4) (TMPyP=tetrakis(N-methylpyridinium-4-y1)porphyrin)--were obtained by methylation of the corresponding complexes with methyl iodide and unambiguously characterized. The binding interactions and photocleavage activities of the water-soluble lanthanide(III) porphyrinate complexes towards DNA were investigated by UV-visible, fluorescence, and near-infrared luminescence spectroscopy, as well as circular dichroism and gel electrophoresis.     

Synthesis, characterisation and magnetic study of a cyano-substituted dysprosium double decker single-molecule magnet

Bis(octacyanophthalocyanine)dysprosium(III) (1) has been synthesised, characterised and magnetically studied. By the incorporation of cyano substituents on the phthalocyanine (Pc) rings, a starting point has been created for the chemical modification of double deckers for the purpose of surface self-assembly. The modification of the rings leaves the magnetic properties of the double decker largely unaffected.     

Lanthanide amido complexes incorporating amino-coordinate-lithium bridged bis(indolyl) ligands: synthesis, characterization, and catalysis for hydrophosphonylation of aldehydes and aldimines

Two series of new lanthanide amido complexes supported by bis(indolyl) ligands with amino-coordinate-lithium as a bridge were synthesized and characterized. The interactions of [(Me(3)Si)(2)N](3)Ln(III)(μ-Cl)Li(THF)(3) with 2 equiv of 3-(CyNHCH(2))C(8)H(5)NH in toluene produced the amino-coordinate-lithium bridged bis(indolyl) lanthanide amides [μ-{[η(1):η(1):η(1):η(1)-3-(CyNHCH(2))Ind](2)Li}Ln[N(SiMe(3))(2)](2)] (Cy = cyclohexyl, Ind = Indolyl, Ln = Sm (1), Eu (2), Dy (3), Yb (4)) in good yields. Treatment of [μ-{[η(1):η(1):η(1):η(1)-3-(CyNHCH(2))Ind](2)Li}Ln[N(SiMe(3))(2)](2)] with THF gave new lanthanide amido complexes [μ-{[η(1):η(1)-3-(CyNHCH(2))Ind](2)Li(THF)}Ln[N(SiMe(3))(2)](2)] (Ln = Eu (5), Dy (6), Yb (7)), which can be transferred to amido complexes 2, 3, and 4 by reflux the corresponding complexes in toluene. Thus, two series of rare-earth-metal amides could be reciprocally transformed easily by merely changing the solvent in the reactions. All new complexes 1-7 are fully characterized including X-ray structural determination. The catalytic activities of these new lanthanide amido complexes for hydrophosphonylation of both aromatic and aliphatic aldehydes and various substituted aldimines were explored. The results indicated that these complexes displayed a high catalytic activity for the C-P bond formation with employment of low catalyst loadings (0.1 mol?% for aldehydes and 1 mol?% for aldimines) under mild conditions. Thus, it provides a convenient way to prepare both α-hydroxy and α-amino phosphonates.     

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.     

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.     

Nature of the near‐IR band in the electronic absorption spectra of neutral bis(tetrapyrrole) rare earth(III) complexes: Time‐dependent density functional theory calculations

The nature of the near‐IR band in the electronic absorption spectra of bis(tetrapyrrole) rare earth(III) complexes Y(Pc)₂ (1), La(Pc)₂ (2), Y(Pc)(Por) (3), Y(Pc)[Pc(α‐OCH₃)₄] (4), Y(Pc)[Pc(α‐OCH₃)₈] (5), and Y(Pc)[Pc(β‐OCH₃)₈] (6) was studied on the basis of time‐dependent density functional theory (TD‐DFT) calculations. The electronic dipole moment along the z‐axis in the electronic transition of the near‐IR band in all the studied neutral bis(tetrapyrrole) yttrium(III) and lanthanum(III) double‐deckers is well explained on the basis of the composition analysis of the orbitals involved. The electronic transition in the near‐IR band causes the reversion of the orbital orientation of one tetrapyrrole ring in both homoleptic and heteroleptic bis(tetrapyrrole) rare earth complexes and induces electron transfer from the tetrapyrrole ring with lower orbital energy to the other ring in the heteroleptic bis(tetrapyrrole) rare earth(III) complexes. The near‐IR band can work as an ideal characteristic absorption band to reflect the π–π interaction between the two tetrapyrrole rings in bis(tetrapyrrole) rare earth(III) double‐decker complexes because of its peculiar electronic transition nature. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010