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.     

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).     

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.     

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.     

Conformational effects, molecular orbitals, and reaction activities of bis(phthalocyaninato) lanthanum double-deckers: density functional theory calculations

The conformational effects on the frontier molecular orbital energy and stability for reduced, neutral, and oxidized bis(phthalocyaninato) lanthanum double-deckers have been revealed on the basis of density functional theory calculations. Calculation results indicate that the frontier orbital coupling degree changes along with the molecular conformation of the double-decker compound, first decreasing along with the increase of rotation angle β from 0 to 20° and then increasing along with the increase of rotation angle β from 20 to 45°. In addition, the stability for the three forms of double-decker changes in the same order, but first increasing and then decreasing along with the change of the rotation angle β in the range of 0 to 45° with a rotation energy barrier of (31.3 ± 3.1) kJ mol(-1) at 20°. This reveals that the rotation of the two phthalocyanine rings for the reduced, neutral, and oxidized bis(phthalocyaninato) lanthanum double-deckers are able to occur at room temperature. Nevertheless, the superior coordination reaction activity of the neutral bis(phthalocyaninato) lanthanum double-decker complex over their reduced form in forming sandwich-type tris(phthalocyaninato) lanthanum triple-decker compounds has also been clearly clarified on the basis of comparative calculations on the Fukui function of [La(Pc)(2)] and [La(Pc)(2)](-) using the DFT method. Fukui function analysis reveals the reaction center of the 18-electron-π-conjugated core in the bis(phthalocyaninato) lanthanum double-decker molecule against both electrophilic and radical attack. Nevertheless, the larger global chemical softness (S) for the neutral [La(Pc)(2)] than the reduced form [La(Pc)(2)](-) indicates the higher reaction activity of the former form over the latter one. This explains well the experimental findings that only the neutral instead of the reduced form of bis(tetrapyrrole) rare earth double-decker complexes, containing at least one phthalocyanine ligand, could be employed as starting materials towards the preparation of tris(tetrapyrrole) rare earth triple-decker complexes by a solution process.     

Investigation of rational syntheses of heteroleptic porphyrinic lanthanide (europium, cerium) triple-decker sandwich complexes

The use of lanthanide triple-decker sandwich molecules containing porphyrins and phthalocyanines in molecular information storage applications requires the ability to attach monomeric triple deckers or arrays of triple deckers to electroactive surfaces. Such applications are limited by existing methods for preparing triple deckers. The reaction of a lanthanide porphyrin half-sandwich complex ((Por)M(acac)) with a dilithium phthalocyanine (PcLi2) in refluxing 1,2,4-trichlorobenzene (bp 214 degrees C) affords a mixture of triple deckers of composition (Pc)M(Pc)M(Por), (Por)M(Pc)M(Por), and (Pc)M(Por)M(Pc). We have investigated more directed methods for preparing triple deckers of a given type with distinct metals in each layer. Application of the method of Weiss, which employs reaction of a (Por)M(acac) species with a lanthanide double decker in refluxing 1,2,4-trichlorobenzene, afforded the desired triple decker in some cases but a mixture of triple deckers in others. The approach we developed employs in situ formation of the lanthanide reagent EuCl[N(SiMe3)2]2 or CeI[N(SiMe3)2]2, which upon reaction with a porphyrin affords the half-sandwich complex (Por)EuX or (Por)CeX' (X = Cl, N(SiMe3)2; X' = I, N(SiMe3)2). Subsequent reaction with PcLi2 gives the double decker (Por)M(Pc). The (Por(1))EuX half-sandwich complex gave the desired triple decker upon reaction with (Pc)Eu(Pc) but little of the desired product upon reaction with (Por(2))Eu(Pc). The (Por(1))CeX' half-sandwich complex reacted with europium double deckers (e.g., (tBPc)Eu(Por(2)), (tBPc)2Eu) to give the triple deckers (Por(1))Ce(tBPc)Eu(Por(2)) and (Por(1))Ce(tBPc)Eu(tBPc) in a rational manner (tB = tetra-tert-butyl). The reactions yielding the half-sandwich, double-decker, and triple-decker complexes were performed in refluxing bis(2-methoxyethyl) ether (bp 162 degrees C). The porphyrins incorporated in the various triple deckers include meso-tetrapentylporphyrin, meso-tetra-p-tolylporphyrin, octaethylporphyrin, and meso-tetraarylporphyrins bearing iodo, ethynyl, or iodo and ethynyl substituents. The triple deckers bearing iodo and/or ethynyl substituents constitute useful building blocks for information storage applications.     

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 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.     

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.     

Structures and spectroscopic properties of bis(phthalocyaninato) yttrium and lanthanum complexes: theoretical study based on density functional theory calculations

Density functional theory (DFT) calculations were carried out to describe the molecular structures, molecular orbitals, atomic charges, UV-vis absorption spectra, IR, and Raman spectra of bis(phthalocyaninato) rare earth(III) complexes M(Pc)(2) (M = Y, La) as well as their reduced products [M(Pc)(2)](-) (M = Y, La). Good consistency was found between the calculated results and experimental data. Reduction of the neutral M(Pc)(2) to [M(Pc)(2)]- induces the reorganization of their orbitals and charge distribution and decreases the inter-ring interaction. With the increase of ionic size from Y to La, the inter-ring distance of both the neutral and reduced double-decker complexes M(Pc)(2) and [M(Pc)(2)](-) (M = Y, La) increases, the inter-ring interaction and splitting of the Q bands decrease, and corresponding bands in the IR and Raman spectra show a red shift. The orbital energy level and orbital nature of the frontier orbitals are also described and explained in terms of atomic character. The present work, representing the first systemic DFT study on the bis(phthalocyaninato) yttrium and lanthanum complexes sheds further light on clearly understanding structure and spectroscopic properties of bis(phthalocyaninato) rare earth complexes.     

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.     

Heteroleptic bis(phthalocyaninato) europium(III) complexes fused with different numbers of 15-crown-5 moieties. Synthesis, spectroscopy, electrochemistry, and supramolecular structure

A series of heteroleptic bis(phthalocyaninato) europium(III) complexes, namely, Eu(Pc)[Pc(15C5)] (2), Eu(Pc)[Pc(opp-15C5)2] (3), Eu(Pc)[Pc(adj-15C5)2] (4), Eu(Pc)[Pc(15C5)3] (5), and Eu(Pc)[Pc(15C5)4] (6) [Pc = unsubstituted phthalocyaninate; Pc(15C5) = 2,3-(15-crown-5)phthalocyaninate; Pc(opp-15C5)2 = 2,3,16,17-bis(15-crown-5)phthalocyaninate; Pc(adj-15C5)2 = 2,3,9,10-bis(15-crown-5)phthalocyaninate; Pc(15C5)3 = 2,3,9,10,16,17-tris(15-crown-5)phthalocyaninate, Pc(15C5)4 = 2,3,9,10,16,17,24,25-tetrakis(15-crown-5)phthalocyaninate], with one, two, three, and four 15-crown-5 voids attached at different positions of one of the two phthalocyaninato ligands in the double-decker molecules, have been devised and prepared by Eu(Pc)(acac)-induced (Hacac = acetylacetone) mixed cyclization of the two corresponding phthalonitriles in the presence of organic base 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) in n-pentanol. For the purpose of comparative studies, homoleptic counterparts Eu(Pc)2 (1) and Eu[Pc(15C5)4]2 (7) have also been prepared. These sandwich double-decker complexes have been characterized by a wide range of spectroscopic methods in addition to elemental analysis. Their electrochemistry has also been studied by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The molecular structure of Eu(Pc)[Pc(15C5)4] (6) has been determined by X-ray diffraction analysis. Their supramolecular structure-formation properties, in particular for compounds 5 and 6 in the presence of potassium ions, have also been comparatively studied for the purpose of future functional investigation.     

Heteroleptic rare earth double-decker complexes with naphthalocyaninato and phthalocyaninato ligands. General synthesis, spectroscopic, and electrochemical characteristics

A novel one-pot procedure starting from the corresponding M(acac)3 x nH2O, metal-free phthalocyanine H2Pc', and naphthalonitrile in the presence of DBU in n-octanol has been developed to prepare heteroleptic (naphthalocyaninato)(phthalocyaninato) rare earth double-decker complexes. A series of six sandwich compounds with different naphthalocyaninato ligands, phthalocyaninato ligands, and central rare earth metals, namely, Sm[Nc(tBu)4](Pc) [Nc(tBu)4 = 3(4),12(13),21(22),30(31)-tetra(tert-butyl)naphthalocyaninato; Pc = unsubstituted phthalocyaninato] (1), Sm(Nc)(Pc') [Pc' = Pc(OC5H11)4, Pc(OC8H17)8; Nc = 2,3-naphthalocyaninato; Pc(OC5H11)4 = 2(3),9(10),16(17),24(25)-tetrakis(3-pentyloxy)phthalocyaninato; Pc(OC8H17)8 = 2,3,9,10,16,17,24,25-octakis(octyloxy)phthalocyaninato] (2, 3), and M(Nc)[Pc(alpha-OC5H11)4] [M = Sm, Eu, Y; Pc(alpha-OC5H11)4 = 1,8,15,22-tetrakis(3-pentyloxy)phthalocyaninato] (4-6), have been isolated in good yields from this one-pot procedure demonstrating the generality of this synthetic pathway. In addition to spectroscopic analyses, the electrochemistry of these novel compounds has also been studied by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods.     

Ruthenium(ii) bis(terpyridine) electron transfer complexes with alkynyl-ferrocenyl bridges: synthesis, structures, and electrochemical and spectroscopic studies

Two novel alkynyl-bridged symmetric bis-tridentate ligands 1,2-bis(1'-[4'-(2,2':6',2'-terpyridinyl)]ferrocenyl)ethyne (; tpy-Fc-C[triple bond, length as m-dash]C-Fc-tpy; Fc = ferrocenyl; tpy = terpyridyl) and 1,4-bis(1'-[4'-(2,2':6',2'-terpyridinyl)]ferrocenyl)-1,3-butadiyne (; tpy-Fc-C[triple bond, length as m-dash]C-C[triple bond, length as m-dash]C-Fc-tpy) and their Ru(2+) complexes and have been synthesized and characterized by cyclic voltammetry, UV-vis and luminescence spectroscopy, and in the case of by single-crystal X-ray diffraction. Cyclic voltammograms of both compounds, and , display two severely overlapping ferrocene-based oxidative peaks with only one reductive peak. The redox behavior of and is dominated by the Ru(2+)/Ru(3+) redox couple (E(1/2) from 1.33 to 1.34 V), the Fe(2+)/Fe(3+) redox couples (E(1/2) from 0.46 to 0.80 V), and the tpy/tpy(-)/tpy(2-) redox couples (E(1/2) from -1.19 to -1.48 V). The UV-vis spectra of and show absorption bands assigned to the (1)[(d(π)(Fe))(6)] → (1)[(d(π)(Fe))(5)(π*(tpy)(Ru))(1)] MMLCT transition at ～555 nm. Complexes and are luminescent in H(2)O-CH(3)CN (4?:?1, v/v) solution at room temperature, and exhibits the strongest luminescence intensity (λ(max)(em): 710 nm, Φ(em): 2.28 × 10(-4), τ: 358 ns) relative to analogous ferrocene-based bis(terpyridine) Ru(ii) complexes reported so far.     

Isolation and Spectroscopic Characterization of Protonated Mixed [Tetrakis (4-pyridyl)porphyrinato] (phthalocyaninato)Rare Earth (Ⅲ)Double-decker Compounds

IntroductionThe homoleptic sandwich~type porphyrinato and phthalocyaninato metal complexesRE (P) z and RE2 (P) 3 (RE =rare earth 1 P = Por or Pc) have been intensively studied over sev-eral decades due to their potential application in non-linear optical (NLO) materials, molecu-lar electronic and magnetic ..te.i.l.L1--l6j.The double-deckers have also aroused a growing interest as structural and spectroscopicsynthetic models for the dimmer of bacteriochlorophyl1 molecules in bacterial pho…     

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.     

Novel one-dimensional polymers generated from p-Ferrocenylbenzoate: syntheses, structures, and magnetic properties

Treatment of p-ferrocenylbenzoate [p-HOOCH4C6Fc, Fc = (eta5-C5H5)Fe(eta5-C5H5)] with Mn(OAc)2 x 2H2O or Cd(OAc)2 x 2H2O afforded one-dimensional linear chain polymer [[Mn(OOCH4C6Fc)2(mu2-OH2)(H2O)2](H2O)]n (1), double-bridge polymer [Mn(mu2-OOCH4C6Fc)2(phen)]n (phen = phenanthroline) (2), and ladderlike framework [[Cd(mu2-OOCH4C6Fc)(eta2-OOCH4C6Fc)(bbp)](CH3OH)]n (bbp = 4,4'-trimethylene-dipyridine) (3). The solution-state cyclic voltammograms indicate that the half-wave potentials of the ferrocenyl moieties in these polymers are all shifted to positive potential compared to that of sodium p-ferrocenylbenzoate. Both 1 and 2 behave as 1D Heisenberg Mn(II) chains with weak intrachain antiferromagnetic interactions between the local high-spin Mn(II) ions, and the exchange coupling parameters J (-5.20 and -3.25 cm(-1) for 1 and 2, respectively) are larger than those of most of the reported di-Mn(II) complexes that contain mu2-aqua and mu2-carboxylato units and one-dimensional Mn(II) carboxylic polymers.     

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.     

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     

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.