Rare Earth Double-decker Complexes Research Articles

Synthesis and characterization of heteroleptic rare earth double-decker complexes involving tetradiazepinoporphyrazine and phthalocyanine macrocycles.

Reaction of (2,3,9,10,16,17,23,24-octabutylphthalocyaninato)lanthanide(iii) acetylacetonates (BuPcLn(acac), 1a-c, Ln = Lu (a), Eu (b), La (c)) with a tetrakis(5,7-bis(4-tert-butylphenyl)-6H-1,4-diazepino)[2,3-b,g,l,q]porphyrazine ligand (tBuPhDzPzH2, 2) produced sandwich compounds (tBuPhDzPz)Ln(BuPc) (3a-c), which represent the first heteroleptic double-deckers incorporating both Pc and DzPz decks. A combination of high-resolution mass spectrometry, UV-Vis/NIR, MCD, and 1H NMR spectroscopy, and square-wave voltammetry provided unambiguous characterization of target complexes 3 indicating that their spectral and electrochemical properties are generally intermediate with respect to their homoleptic relatives. Based on the data of solution-state 1H-1H NMR (COSY, NOESY) correlation spectroscopy supported by DFT calculations, a dimerization tendency of compounds 3 proportional to the Ln(iii) ion size was found. The spectroelectrochemical study of 3 and the corresponding homoleptic double-deckers revealed a pronounced tendency to aggregation of the one-electron oxidized forms of DzPz-containing double-decker complexes compared to homoleptic Pc2Ln compounds.

Raman spectra of rare earth double-decker complexes with porphyrinato and 2,3-naphthalocyaninato ligands

The Raman spectra of the mixed (naphthalocyaninato)[tetrakis(4-[Formula: see text]-butylphenyl)porphyrinato] rare earth double-decker compounds M(Nc)(TBPP) (M = Y, La, Ce, Eu, Dy, Lu) were studied with Density Functional Theory for the first time. The results reveal the fingerprint band for naphthalocyanine to be around 1455–1615 cm[Formula: see text] and porphyrin around 693–749 cm[Formula: see text]. Coupled Nc–Por ring–ring interaction vibration modes are also detected at 1470–1522 cm[Formula: see text], owing to the stretching between the central metal and the N atoms. These vibration modes are recognized as the dominating components in the Raman spectra of those double-decker compounds.

Strong two-photon absorptions in heteroleptic bis(phthalocyaninato) rare earth sandwich complexes

A series of heteroleptic phthalocyaninato rare earth double-decker complexes owning large two-photon absorption cross-sections were reported. The third-order nonlinear optical properties of these heteroleptic phthalocyaninato complexes were experimentally investigated by the Z-scan technique with application of femtosecond (800 nm) pulse lasers. Due to the highly delocalized π-electron system and intense π-π interactions between the phthalocyaninato macrocycles, all complexes were revealed to exhibit large two-photon absorption cross-sections with the value up to 1.83 × 105 GM, which are comparable to those efficient two-photon absorbing materials. The optical limiting behavior of these complexes in chloroform was also investigated by using femtosecond laser pulses. The excellent two-photon absorption properties and optical limiting performance indicate their good application potential in optoelectronic devices.

New mixed rare earth double-decker complexes with octyloxynaphthyl-porphyrinato and phenylthio-naphthalocyaninato ligands – preparation and spectroscopic characterization

Eight new (porphyrinato)(naphthalocyaninato) rare earth(III) double-decker complexes MIII(TONPP)[Nc(PhS)8] [M = La, Pr, Nd, Sm, Eu, Gd, Tb, and Dy; TONPP = 5,10,15,20-tetrakis(4-octyloxynaphthyl) porphyrin; Nc(PhS)8 = 3,4,12,13,21,22,30,31-octa(phenylthio)-2,3-naphthalocyanine] have been prepared and characterized by spectroscopic methods. The UV–vis absorption spectra depend on the central rare earth ionic size, suggesting that all the transitions involve molecular orbitals with contribution from both porphyrin and naphthalocyanine ligands. The IR and Raman spectra of these double-decker compounds were systemically investigated, showing that the electron hole in these mixed double-deckers is mainly localized at the naphthalocyanine ring. Their sandwich nature was also characterized by MS, EA, and 1H NMR techniques.

A series of homoleptic bis(phthalocyaninato) rare earth sandwich complexes with large two-photon absorption cross-section

The third-order nonlinear optical properties of a series of homoleptic substituted phthalocyaninato rare earth double-decker complexes were experimentally investigated by the Z-scan technique at the wavelength of 800 nm. All complexes were revealed to exhibit large two-photon absorption cross-sections. The measured two-photon absorption values of these complexes remain constant at different laser intensities, indicating nonlinearity is originated from pure two-photon absorption behavior. In addition, the two-photon absorption cross-section of these complexes increases along with the decrease of the rare earth atomic radius, suggesting that intense intramolecular π–π interaction between the phthalocyaninato macrocycles improves the third-order nonlinear optical properties. The optical limiting behavior of these complexes in chloroform was also investigated by using femtosecond laser pulses. The excellent two-photon absorption properties and optical limiting performance indicate their good application potential in photonic and optoelectronic devices.

Chiral bis(phthalocyaninato) yttrium double-decker complexes. Synthesis, structure, spectroscopy, and electrochemistry

Two new chiral sandwich-type bis(phthalocyaninato) yttrium double-decker complexes including the homoleptic species (R)- and (S)-Y[Pc(OBNP)4]2 (1) and a heteroleptic analogue (R)- and (S)-Y(Pc)[Pc(OBNP)4] (2) {Pc = unsubstituted phthalocyaninate; [Pc(OBNP)4] = tetrakis(dinaphtho[1,2-e:1',2'-g]-1,4-(dioxocine)[2,3-b;2',3'-k;2'',3''-t;2''',3'''-c']phthalocyaninate)} have been synthesized and spectroscopically characterized. In particular, the molecular structures of (R)- and (S)-1 were determined on the basis of single crystal X-ray diffraction analysis, representing the first structurally characterized chiral bis(phthalocyaninato) rare earth double-decker complexes. Perfect mirror-image CD signals observed in the whole phthalocyanine absorption range of the CD spectra of the (R)- and (S)-enantiomers for both compounds reveal the effective chiral information transfer from the peripheral binaphthyl moieties to the phthalocyanine chromophore, while the difference observed in the CD spectrum between 1 and 2 indicates the effect of the chiral substituent number on the chiral information transfer. Nevertheless, the absolute structures unambiguously elucidated for both enantiomers of the homoleptic double-decker render it possible to clarify the chirality of optically active bis(phthalocyaninato) rare earth compounds.

Constructing bis(porphyrinato) rare earth double-decker complexes involving N-confused porphyrin.

Reaction of metal-free N-confused 5,10,15,20-tetrakis(4-chlorophenyl)porphyrin (H2NTClPP) with metal-free 5,10,15,20-tetrakis[(4-tert-butyl)phenyl]porphyrin (H2TBPP) in the presence of M(III)(acac)3·nH2O (acac = acetylacetonate) in refluxing 1,2,4-trichlorobenzene (TCB) led to the isolation of heteroleptic bis(porphyrinato) rare earth compounds M(III)(HNTClPP)(TBPP) (M = La, Pr) (1, 2) in 6.7-10% yield. These represent the first examples of sandwich-type porphyrin rare earth double-decker complexes that involve N-confused porphyrin ligand. Different from their homoleptic bis(porphyrinato) rare earth double-decker counterparts HM(III)(TBPP)2 (M = La, Pr) (3, 4), the acidic proton in the heteroleptic analogues was revealed to localize at the inverted pyrrole nitrogen atom of the N-confused porphyrin ligand on the basis of NMR spectroscopic studies. Nevertheless, their heteroleptic bis(porphyrinato) sandwich molecular nature was confirmed on the basis of single crystal X-ray diffraction analysis over the praseodymium double-decker complex.

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.

Crystal structure and self-assembly property of sandwich-type mixed (phthalocyaninato)(porphyrinato) rare earth double-decker complexes

Two sandwich-type mixed (phthalocyaninato)(porphyrinato) rare earth double-decker complexes, M(Pc)(TPP) [H2Pc=phthalocyanine; H2TPP=meso-tetra(phenyl)porphyrin] (M=Eu, Lu) (1, 2) were synthesized and the structure of Lu(Pc)(TPP) was characterized by X-ray single-crystal diffraction method. Crystal data: triclinic, space group P1¯, Z=2, C77H45Cl3LuN12, Mr=1419.57, a=12.573(5), b=12.911(5), c=22.935(5)Å, α=103.793(5)°, β=101.363(5)°, γ=93.682(5)°, V=3521(2)Å3, μ(Mo Kα)=1.196mm−1, F(000)=1426, R=0.0590, and wR=0.1639 for 9745 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°. The self-assembled nano-structures of both complexes 1 and 2 were systematically investigated by electronic absorption and Fourier transform infrared (FT-IR) spectroscopy, transmission electronic microscopy (TEM), scanning electronic microscopy (SEM), and X-ray diffraction (XRD) techniques, revealing the effect of molecular structure on the dimension of self-assembled nano-structures.

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.

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.

Optically Active Homoleptic Bis(phthalocyaninato) Rare Earth Double-Decker Complexes Bearing Peripheral Chiral Menthol Moieties: Effect of π−π Interaction on the Chiral Information Transfer at the Molecular Level

With the view to creating novel sandwich-type phthalocyaninato rare earth complexes toward new applications in material science and catalysis, d- and l-enantiomers of a series of optically active homoleptic bis(phthalocyaninato) rare earth double-deckers with four chiral menthol moieties at the peripheral positions of the phthalocyanine ligand, M(Pc*)(2) [Pc* = 2(3),9(10),16(17),23(24)-tetrakis(2-isopropyl-5-methylcyclohexoxyl)phthalocyanine; M = Eu, Y, Lu] (1-3), have been designed and prepared by treating (d)- or (l)-4-(2-isopropyl-5-methylcyclohexoxyl)-1,2-dicyanobenzene with the corresponding M(acac)(3).nH(2)O (acac = acetylacetonate) in the presence of the organic base 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) in refluxing n-pentanol. For the purpose of comparative study, heteroleptic bis(phthalocyaninato) europium analogues (d)- and (l)-Eu(Pc)(Pc*) (4) as well as the unsubstituted homoleptic bis(phthalocyaninato) europium counterpart Eu(Pc)(2) (5) were also prepared. The novel synthesized bis(phthalocyaninato) rare earth double-deckers have been characterized by a wide range of spectroscopic methods including MS, (1)H NMR, IR, and electronic absorption spectroscopic measurements in addition to elemental analysis. In contrast to the CD silent monomeric metal-free 2(3),9(10),16(17),23(24)-tetrakis(2-isopropyl-5-methylcyclohexoxyl)phthalocyanine, observation of the CD signal in the N absorption region of 4 reveals the significant effect of intramolecular pi-pi interaction on intensifying the asymmetrical perturbation of the chiral menthol units onto the phthalocyanine chromophore, which results in successful chiral information transfer from menthol moieties to the phthalocyanine chromophore at a molecular level in the heteroleptic double-decker compound 4 despite the lack of CD signal in the Soret and Q absorption regions of the phthalocyanine ligand. This is further supported by the optical activity of homoleptic bis(phthalocyaninato) rare earth double-deckers M(Pc*)(2) (1-3), as revealed by the CD signals even in the Soret and Q absorption regions according to the CD spectroscopic result, indicating the intensified asymmetrical perturbation of the chiral menthol units onto the phthalocyanine chromophores along with the increase in the chiral menthol substituent number from 4 to 1-3. The present result at the molecular level is helpful for understanding the chiral information transfer mechanism at the supermolecular level. In addition, the electrochemical properties of bis(phthalocyaninato) rare earth complexes have also been comparatively investigated by cyclic voltammetry and differential pulse voltammetry.

Bis[1,4,8,11,15,18,22,25-octa(butyloxyl)phthalocyaninato] rare earth double-decker complexes: synthesis, spectroscopy, and molecular structure

Homoleptic octa-alpha-substituted bis(phthalocyaninato) rare earth double-deckers HM(III)[Pc(alpha-OC(4)H(9))(8)](2) [M = Eu (1), Y (2); Pc(alpha-OC(4)H(9))(8) = 1,4,8,11,15,18,22,25-octa(butyloxyl)phthalocyanine] have been prepared by treating the metal-free phthalocyanine H(2)Pc(alpha-OC(4)H(9))(8) with the corresponding M(acac)(3).nH(2)O (acac = acetylacetonate) in the presence of organic base 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and benzo-18-crown-6/benzo-15-crown-5 in refluxing n-octanol. To the best of our knowledge, it is the first example of homoleptic non-peripherally octa(alkoxyl)-substituted bis(phthalocyaninato) rare earth complexes. Comparative studies on a series of reactions reveal the key role of DBU as catalyst and crown ether as template in the formation of homoleptic rare earth double-decker complexes with structurally highly deformed non-peripherally octa(butyloxy)-substituted phthalocyanine ligand. The molecular structure of complex 1 has been determined by single-crystal X-ray diffraction analysis. The metal center is octa-coordinated by the isoindole nitrogen atoms of the two phthalocyaninato ligands, forming a distorted square antiprism. Despite the extremely non-planar saddle conformation employed by metal free H(2)Pc(alpha-OC(4)H(9))(8) molecule, both the phthalocyanine rings in HEu(III)[Pc(alpha-OC(4)H(9))(8)](2) (1) adopt a conformation that is domed toward the europium center, similar to corresponding unsubstituted or beta-substituted bis(phthalocyaninato) analogues. These two bis(phthalocyaninato) rare earth double-deckers have also been characterized by a wide range of spectroscopic methods including MS, (1)H NMR, UV-vis, IR, and EPR. Structural and spectroscopic studies reveal that the pi-pi interaction between the two Pc(alpha-OC(4)H(9))(8) rings is weaker than that for the corresponding unsubstituted or beta-substituted bis(phthalocyaninato) analogues.

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

Mixed (Phthalocyaninato)(Porphyrinato) Rare Earth Double-Decker Complexes withC4Chirality: Synthesis, Resolution, and Absolute Configuration Assignment

Mixed (phthalocyaninato)(porphyrinato) rare earth double-decker complexes [HM(III){Pc(alpha-3-OC(5)H(11))(4)}{TOAPP}] [Pc(alpha-3-OC(5)H(11))(4) = 1,8,15,22-tetrakis(3-pentyloxy)-phthalocyaninate; TOAPP = meso-tetrakis(4-octylamino-phenyl)porphyrinate; M = Y (1), Ho (2)] were prepared as a racemic mixture by treating metal-free phthalocyanine H(2)Pc(alpha-3-OC(5)H(11))(4) with half-sandwich complexes [M(III)(acac)(TOAPP)], generated in situ from M(acac)(3).nH(2)O and H(2)TAPP [TAPP = meso-tetrakis(4-amino-phenyl)porphyrinate], in refluxing 1-octanol. The obtained double-deckers were characterized by elemental analysis and various spectroscopic methods. The molecular structures of 1 and 2 were determined by single-crystal X-ray diffraction analysis. The compounds crystallize in the triclinic system with a pair of enantiomeric double-deckers per unit cell. Resolution of 1 and 2 was achieved using a chiral HPLC technique combined with the formation of their diastereomeric mixture using L-Boc-Phe-OH as the chiral resolving agent, yielding for the first time the pure diastereoisomers of chiral mixed (phthalocyaninato)(porphyrinato) rare earth double-decker complexes with C(4) symmetry. The absolute configuration of these chiral complexes was assigned by comparing the experimental circular dichroism spectrum with a simulated one on the basis of time-dependent density functional theory calculations.

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.

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.

Vibrational spectroscopy of phthalocyanine and naphthalocyanine in sandwich-type (na)phthalocyaninato and porphyrinato rare earth complexes: Part 14. The infrared and Raman characteristics of phthalocyanine in “pinwheel-like” homoleptic bis[1,8,15,22-tetrakis(3-pentyloxy)phthalocyaninato] rare earth(III) double-decker complexes

The infrared (IR) spectroscopic data and Raman spectroscopic properties for a series of 13 “pinwheel-like” homoleptic bis(phthalocyaninato) rare earth complexes M[Pc(α-OC 5H 11) 4] 2 [M = Y and Pr–Lu except Pm; H 2Pc(α-OC 5H 11) 4 = 1,8,15,22-tetrakis(3-pentyloxy)phthalocyanine] have been collected and comparatively studied. Both the IR and Raman spectra for M[Pc(α-OC 5H 11) 4] 2 are more complicated than those of homoleptic bis(phthalocyaninato) rare earth analogues, namely M(Pc) 2 and M[Pc(OC 8H 17) 8] 2, but resemble (for IR) or are a bit more complicated (for Raman) than those of heteroleptic counterparts M(Pc)[Pc(α-OC 5H 11) 4], revealing the decreased molecular symmetry of these double-decker compounds, namely S 8. Except for the obvious splitting of the isoindole breathing band at 1110–1123 cm −1, the IR spectra of M[Pc(α-OC 5H 11) 4] 2 are quite similar to those of corresponding M(Pc)[Pc(α-OC 5H 11) 4] and therefore are similarly assigned. With laser excitation at 633 nm, Raman bands derived from isoindole ring and aza stretchings in the range of 1300–1600 cm −1 are selectively intensified. The IR spectra reveal that the frequencies of pyrrole stretching and pyrrole stretching coupled with the symmetrical C H bending of –CH 3 groups are sensitive to the rare earth ionic size, while the Raman technique shows that the bands due to the isoindole stretchings and the coupled pyrrole and aza stretchings are similarly affected. Nevertheless, the phthalocyanine monoanion radical Pc′ − IR marker band of bis(phthalocyaninato) complexes involving the same rare earth ion is found to shift to lower energy in the order M(Pc) 2 > M(Pc)[Pc(α-OC 5H 11) 4] > M[Pc(α-OC 5H 11) 4] 2, revealing the weakened π–π interaction between the two phthalocyanine rings in the same order.

Infrared spectroscopic characteristics of phthalocyanine in mixed [tetrakis(4-chlorophenyl)porphyrinato](phthalocyaninato) rare earth double-deckers

The infra-red (IR) spectroscopic data for a series of 15 mixed [tetrakis(4-chlorophenyl)porphyrinato](phthalocyaninato) rare earth double-decker complexes with tervalent rare earths M III(TClPP)(Pc) (M = Y, La, …, Lu except Ce and Pm) and intermediate-valent cerium Ce(TClPP)(Pc) have been collected with resolution of 2 cm −1. For M III(TClPP)(Pc), typical IR marker band of the monoradical anion Pc − shows the most intense absorption band whose frequency linearly varies in the range from 1311 cm −1 for La(TClPP)(Pc) to 1320 cm −1 for Lu(TClPP)(Pc) along with the decrease of rare earth ionic size. The peaks at 1016–1023 cm −1 are assigned to C Cl stretchings. For Ce(TClPP)(Pc), a medium band at 1329 cm −1 with contribution from pyrrole stretching was the marker IR band of phthalocyanine dianion Pc 2−. The TClPP − IR marker band at ca. 1270–1300 cm −1 was not observed for these compounds. These facts indicate that the hole in these double-deckers is mainly localized at the phthalocyanine ring.