High repetition rates optically active langasite electro-optically Q-switched laser at 1.34 µm.

An electro-optically Q-switched pulsed laser at 1.34 µm with a repetition rate of 100 kHz applying optically active langasite (La3Ga5SiO14) crystal has been reported. With Nd:YVO4 as laser crystal, the electro-optically Q-switched pulsed lasers were obtained with the maximum repetition rate of 100 kHz, maximum average output power of 2.42 W, and a minimum pulse width of 2.4 ns. Based on the theory of rate equations, the optimal pulse energy of the electro-optical Q-switching could be calculated. The experimental results have been found to be matched well with the theoretical calculations. To the best of our knowledge, this work presents the highest repetition rate and shortest pulse width which are achieved by an electric-optic LGS Q-switching at the wavelength of 1.34 µm, and it enriches the material categories for generating the high repetition rate pulsed laser.

Morphology controlled nanostructures self-assembled from phthalocyanine derivatives bearing alkylthio moieties: effect of sulfur-sulfur and metal-ligand coordination on intermolecular stacking.

To investigate the effect of sulfur-sulfur and metal-ligand coordination on the molecular structure and morphology of self-assembled nanostructures, metal-free 2,3,9,10,16,17,23,24-octakis(isopropylthio)phthalocyanine H(2)Pc(ß-SC(3)H(7))(8) (1) and its copper and lead congeners CuPc(ß-SC(3)H(7))(8) (2) and PbPc(ß-SC(3)H(7))(8) (3) are synthesized and fabricated into organic nanostructures by a phase-transfer method. The self-assembly properties are investigated by electronic absorption and Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Experimental results reveal different molecular packing modes in these aggregates, which in turn result in self-assembled nanostructures with different morphologies ranging from nanobelts for 1 through nanoribbons for 2 to cluster nanoflowers for 3. Intermolecular π-π and sulfur-sulfur interactions between metal-free phthalocyanine 1 lead to the formation of nanobelts. The additional Cu-S coordination bond between the central copper ion of 2 and the sulfur atom of the adjacent molecule of 2 in cooperation with the intermolecular π-π stacking interaction increases the intermolecular interaction, and results in the formation of long nanoribbons for 2. In contrast to compounds 1 and 2, the special molecular structure of complex 3, together with the intermolecular π-π stacking interaction and additional Pb-S coordination bond, induces the formation of Pb-connected pseudo-double-deckers during the self-assembly process, which in turn further self-assemble into cluster nanoflowers. In addition, good semiconducting properties of the nanostructures fabricated from phthalocyanine derivatives 1-3 were also revealed by I-V measurements.

2,3-Dicyano-4-[(4-methyl-phenyl-sulfon-yl)-oxy]phenyl 4-methyl-benzene-sulfonate.

In the title compound, C(22)H(16)N(2)O(6)S(2), the dihedral angle formed by the mean planes of the two benzene rings of the 4-methyl-phenyl-sulfonate groups is 21.9 (1)° and these rings form dihedral angles of 48.26 (9) and 52.73 (9)° with the central benzene ring.

Watt-level self-frequency-doubling Nd:GdCOB lasers.

Laser-diode (LD) pumped self-frequency doubling (SFD) Nd:GdCa4O(BO3)3 (Nd:GdCOB) miniature laser was demonstrated. The output power as high as 1.35 W was achieved which is over than five times than previous values for Nd:LnCa4O(BO3)3 (Ln=Y or Gd) SFD lasers and becomes the highest continuous-wave output power in this field to our knowledge. The maximum optical conversion efficiency is 17%. By comparison, we found that the cutting direction along its optimal phase-matching direction out of the principal planes is the determining factor resulting in this watt-level efficient output power. Different with previous studies, the emission wavelength is centered at about 545 nm. We believed that this efficient laser will become the most competitive one in the existing commercial green lasers, especially in the laser display, medical treatment and spectroscopic analysis etc.

Optically active homoleptic bis(phthalocyaninato) rare earth double-decker complexes bearing peripheral chiral menthol moieties: effect of pi-pi 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.

Design, synthesis, characterization, and OFET properties of amphiphilic heteroleptic tris(phthalocyaninato) europium(III) complexes. The effect of crown ether hydrophilic substituents.

Two amphiphilic heteroleptic tris(phthalocyaninato) europium complexes with hydrophilic crown ether heads and hydrophobic octyloxy tails [Pc(mCn)(4)]Eu[Pc(mCn)(4)]Eu[Pc(OC(8)H(17))(8)] [m = 12, n = 4, H(2)Pc(12C4)(4) = 2,3,9,10,16,17,23,24-tetrakis(12-crown-4)phthalocyanine; m = 18, n = 6, H(2)Pc(18C6)(4) = 2,3,9,10,16,17,23,24-tetrakis(18-crown-6)phthalocyanine; H(2)Pc(OC(8)H(17))(8) = 2,3,9,10,16,17,23,24-octakis(octyloxy)phthalocyanine] (1, 2) were designed and prepared from the reaction between homoleptic bis(phthalocyaninato) europium compound [Pc(mCn)(4)]Eu[Pc(mCn)(4)] (m = 12, n = 4; m = 18, n = 6) and metal-free H(2)Pc(OC(8)H(17))(8) in the presence of Eu(acac)(3).H(2)O (Hacac = acetylacetone) in boiling 1,2,4-trichlorobenzene. These novel sandwich triple-decker complexes were characterized by a wide range of spectroscopic methods and electrochemically studied. With the help of the Langmuir-Blodgett technique, these typical amphiphilic triple-decker complexes were fabricated into organic field effect transistors (OFET) with top contact configuration on bare SiO(2)/Si substrate, hexamethyldisilazane-treated SiO(2)/Si substrate, and octadecyltrichlorosilane (OTS)-treated SiO(2)/Si substrate, respectively. The device performance is revealed to be dependent on the species of crown ether substituents and substrate surface treatment. OFETs fabricated from the triple decker with 12-crown-4 hydrophilic substituents, 1, allow the hole transfer in the direction parallel to the aromatic phthalocyanine rings. In contrast, the devices of a triple-decker compound containing 18-crown-6 as hydrophilic heads, 2, transfer holes in a direction along the long axis of the assembly composed of face-to-face aggregated triple-decker molecules, revealing the effect of molecular structure, specifically the crown ether substituents on the film structure and OFET functional properties. The carrier mobility for hole as high as 0.33 cm(2) V(-1) s(-1) and current modulation of 7.91 x 10(5) were reached for the devices of triple-decker compound 1 deposited on the OTS-treated SiO(2)/Si substrates, indicating the effect of substrate surface treatment on the OFET performance due to the improvement on the film quality as demonstrated by the atomic force microscope investigation results.

Morphology-controlled self-assembled nanostructures of 5,15-di[4-(5-acetylsulfanylpentyloxy)phenyl]porphyrin derivatives. Effect of metal-ligand coordination bonding on tuning the intermolecular interaction.

Novel metal-free 5,15-di[4-(5-acetylsulfanylpentyloxy)phenyl]porphyrin H2[DP(CH3COSC5H10O)2P] (1) and its zinc congener Zn[DP(CH3COSC5H10O)2P] (2) were designed and synthesized. Single-crystal X-ray diffraction (XRD) analysis confirmed the tetrapyrrole nature of these two compounds, revealing the existence of metal-ligand coordination bond between the carbonyl oxygen in the aryloxy side chain of meso-attached phenyl group in the porphyrin molecule with the zinc center of neighboring porphyrin molecule in the crystal structure of 2. This intermolecular Zn-O coordination bond induces the formation of a supramolecular chain structure in which the porphyrinato zinc moieties are arranged in a "head-to-tail" mode (J-aggregate), which is in contrast to a "face-to-face" stacking mode (H-aggregate) in the supramolecular structure formed depending on the C-H...pi interaction in the crystal of 1. Their self-assembling properties in MeOH and n-hexane were comparatively investigated by scanning electronic microscopy and XRD technique. Intermolecular pi-pi interaction of metal-free porphyrin 1 leads to the formation of hollow nanospheres and nanoribbons in MeOH and n-hexane, respectively. In contrast, introduction of additional Zn-O coordination bond for porphyrinato zinc complex 2 induces competition with intermolecular pi-pi interaction, resulting in nanostructures with nanorod and hollow nanosphere morphology in MeOH and n-hexane. The IR and XRD results clearly reveal the presence and absence of such metal-ligand coordination bond in the nanostructures formed from porphyrinato zinc complex 2 and metal-free porphyrin 1, respectively, which is further unambiguously confirmed by the single-crystal XRD analysis result for both compounds. Electronic absorption spectroscopic data on the self-assembled nanostructures reveal the H-aggregate nature in the hollow nanospheres and nanoribbons formed from metal-free porphyrin 1 due to the pi-pi intermolecular interaction between porphyrin molecules and J-aggregate nature in the nanorods and hollow nanospheres of 2 depending on the dominant metal-ligand coordination bonding interaction among the porphyrinato zinc molecules. The present result appears to represent the first effort toward controlling and tuning the morphology of self-assembled nanostructures of porphyrin derivatives via molecular design and synthesis through introduction of metal-ligand coordination bonding interaction. Nevertheless, availability of single crystal and molecular structure revealed by XRD analysis for both porphyrin derivatives renders it possible to investigate the formation mechanism as well as the molecular packing conformation of self-assembled nanostructures of these typical organic building blocks with large conjugated system in a more confirmed manner.

Efficient high repetition rate electro-optic Q-switched laser with an optically active langasite crystal.

With an optically active langasite (LGS) crystal as the electro-optic Q-switch, we demonstrate an efficient Q-switched laser with a repetition rate of 200 kHz. Based on the theoretical analysis of the interaction between optical activity and electro-optic property, the optical activity of the crystal has no influence on the birefringence during Q-switching if the quarter wave plate used was rotated to align with the polarization direction. With a Nd:LuVO4 crystal possessing a large emission cross-section and a short fluorescence lifetime as the gain medium, a stable LGS Q-switched laser was designed with average output power of 4.39 W, corresponding to a slope efficiency of 29.4% and with a minimum pulse width of 5.1 ns. This work represents the highest repetition rate achieved so far in a LGS Q-switched laser and it can provide a practical Q-switched laser with a tunable high repetition rates for many applications, such as materials processing, laser ranging, medicine, military applications, biomacromolecule materials, remote sensing, etc.

Infrared spectra of phthalocyanine and naphthalocyanine in sandwich-type (na)phthalocyaninato and porphyrinato rare earth complexes. Part 3. The effects of substituents and molecular symmetry on the infrared characteristics of phthalocyanine in bis(phthalocyaninato) rare earth complexes.

The infra-red (IR) spectroscopic data for a series of 45 homoleptic unsubstituted and substituted bis(phthalocyaninato) rare earth complexes M(Pc)2 and M(Pc*)2 [M=Y, La...Lu except Pm; H2Pc=phthalocyanine; H2Pc*=2,3,9,10,16,17,24,25-octakis(octyloxy)phthalocyanine (H2OOPc) and 2(3),9(10),16(17),24(25)-tetra(tert-butyl)phthalocyanine (H2TBPc)] have been collected with resolution of 2 cm(-1). The IR spectra for M(Pc)2 and M(OOPc)2 are much simpler than those of M(TBPc)2, revealing the relatively higher symmetry of the former two compounds. For M(Pc)2 the Pc-* marker band at 1312-1323 cm(-1), attributed to the pyrrole stretching, and the isoindole stretching band at 1439-1454 cm(-1) are found to be dependent on the central rare earth size, shifting slightly to the higher energy along with the decrease of rare earth radius. The frequency of the vibration at 876-887 cm(-1) is also dependent on the rare earth ionic size. The metal size-sensitivity of this band and theoretical studies render it possible to re-assign it to the coupling of isoindole deformation and aza vibration. The nature of another metal-sensitive vibration mode at 1110-1116 cm(-1), which was previously assigned to the C-H bending, is now re-assigned as an isoindole breathing mode with some small contribution also from C-H in-plane bending. These assignments are supported by comparative studies of the IR spectra of substituted bis(phthalocyaninato) analogues M(OOPc)2 and M(TBPc)2. By comparison between the IR spectra of unsubstituted and substituted bis(phthalocyaninato) rare earth analogues and according to the IR characteristics of alkyl groups, some characteristic vibrational fundamentals due to the Pc rings and the substituents can be separately identified. In conclusion, all the metal size-dependent IR absorptions are composed primarily of the vibrations of pyrrole or isoindole stretching, breathing or deformation or aza stretching of the Pc ring.

2,3,9,10,16,17,24,25-Octakis(octyloxycarbonyl)phthalocyanines. Synthesis, spectroscopic, and electrochemical characteristics.

A series of three novel 2,3,9,10,16,17,24,25-octakis(octyloxycarbonyl)phthalocyanine compounds M[Pc(COOC8H17)8] (M = 2H, Cu, Zn) (1-3) have been synthesized via the cyclic tetramerization of 4,5-di(octyloxycarbonyl)phthalonitrile, which was obtained by a newly developed procedure with o-xylene as starting material, promoted with organic base 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) in the absence and presence of metal salt like M(acac)2.H2O (M = Cu, Zn) in n-octanol at 120 degrees C. In addition to elemental analysis, these novel octakis(octyloxycarbonyl)-substituted phthalocyanine compounds have been characterized by a series of spectroscopic methods. The electrochemistry of these compounds was also studied by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods. A significant shift to the positive direction for both the first oxidation and the first reduction of compound 1, relative to H2Pc, reveals the electron-withdrawing nature of octyloxycarbonyl groups attached to the peripheral positions of phthalocyanine. The effect of peripheral octyloxycarbonyl substitution on the electrochemistry of the series of phthalocyanines 1-3 has been reasonably explained by theoretical calculation results using the density functional theory (DFT) method.

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.

Studies of "pinwheel-like" bis[1,8,15,22-tetrakis(3-pentyloxy)phthalocyaninato] rare earth(III) double-decker complexes.

Homoleptic bis(phthalocyaninato) rare-earth double-deckers complexes [M(III)[Pc(alpha-OC5H11)4]2] (M = Eu, Y, Lu; Pc(alpha-OC5H11)4 = 1,8,15,22-tetrakis(3-pentyloxy)phthalocyaninate) have been prepared by treating the metal-free phthalocyanine H2Pc(alpha-OC5H11)4 with the corresponding M(acac)3.nH2O (acac = acetylacetonate) in refluxing n-octanol. Due to the C4h symmetry of the Pc(alpha-OC5H11)4 ligand and the double-decker structure, all the reactions give a mixture of two stereoisomers with C4h and D4 symmetry. The former isomer, which is a major product, can be partially separated by recrystallization due to its higher crystallinity. The molecular structure of the major isomer of the Y analogue has been determined by single-crystal X-ray diffraction analysis. The metal center is eight-coordinate bound to the isoindole nitrogen atoms of the two phthalocyaninato ligands, forming a distorted square antiprism. Such an arrangement leads to an interesting pinwheel structure when viewed along the C4 axis, which assumes a very unusual S8 symmetry. The major isomers of all these double-deckers have also been characterized with a wide range of spectroscopic methods. A systematic investigation of their electronic absorption and electrochemical data reveals that the pi-pi interaction between the two Pc(alpha-OC5H11)4 rings is weaker than that for the corresponding unsubstituted or beta-substituted bis(phthalocyaninato) analogues.

Synthesis, structure, spectroscopic properties, and electrochemistry of (1,8,15,22-tetrasubstituted phthalocyaninato)lead complexes.

Three (1,8,15,22-tetrasubstituted phthalocyaninato)lead complexes Pb[Pc(alpha-OR)(4)] [H(2)Pc(alpha-OC(5)H(11))(4) = 1,8,15,22-tetrakis(3-pentyloxy)phthalocyanine; H(2)Pc(alpha-OC(7)H(15))(4) = 1,8,15,22-tetrakis(2,4-dimethyl-3-pentyloxy)phthalocyanine; H(2)Pc(alpha-OC(10)H(7))(4) = 1,8,15,22-tetrakis(2-naphthyloxy)phthalocyanine] (1-3) have been prepared as racemic mixtures by treating the corresponding metal-free phthalocyanines H(2)Pc(alpha-OR)(4) (4-6) with Pb(OAc)(2).3H(2)O in refluxing n-pentanol. The molecular structure of Pb[Pc(alpha-OC(5)H(11))(4)] (1) in the solid state has been determined by single-crystal X-ray diffraction analysis. This compound, having a nonplanar structure, crystallizes in the monoclinic system with a P2(1)/c space group. Each unit cell contains two pairs of enantiomeric molecules, which are linked by weak coordination of the Pb atom of one molecule with an aza nitrogen atom and its neighboring oxygen atom from the alkoxy substituent of another molecule, forming a pseudo-double-decker supramolecular structure in the crystals with a short ring-to-ring separation, 2.726 A, and thus a strong ring-ring pi-pi interaction. The decreased molecular symmetry for these complexes has also been revealed by the NMR spectra of 1 and 2. The methyl protons of the 3-pentyloxy and 2,4-dimethyl-3-pentyloxy side chains of 1 and 2, respectively, are chemically inequivalent. In addition to the elemental analysis and various spectroscopic characterizations, these compounds have also been electrochemically studied. Two one-electron oxidations and up to five one-electron reductions have been revealed by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods.

The first slipped pseudo-quadruple-decker complex of phthalocyanines.

The first slipped pseudo-quadruple-decker complex of phthalocyanines was formed unexpectedly upon treatment of the protonated double-decker SmIIIH(Pc)[Pc(alpha-OC4H9)8] with NaOH. The supramolecular structure contains two double-decker units linked by two sodium ions by an extremely rare coordination mode of phthalocyanines in which an aza nitrogen atom and two oxygen atoms from neighboring alkoxy substituents form a tridentate ligand.