Germanium porphines and some silicon and germanium phthalocyanines

Kane, Alexander R.; Yalman, Richard G.; Kenney, Malcolm E.

doi:10.1021/ic50070a025

Cited by 32 publications

(11 citation statements)

References 6 publications

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“…This effect has been previously observed in phthalocyanine derivatives [43][44][45] and in other trialkylsilyloxy axially substituted SubPcs prepared by us [36]. The UV-vis spectra of compounds 3-8 show a new band at around 400 nm and a red shift (bathochromic shift) of the Q band (with respect to the unsubstituted SubPc) due to the presence of the thioether groups.…”

Section: Synthesis and Spectroscopic Characterizationsupporting

confidence: 73%

Synthesis and thermotropic properties of hydroxy and silyloxy axially substituted phthalocyanines

Rey

Martínez‐Díaz

Barberá

et al. 2000

J. Porphyrins Phthalocyanines

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Novel boron(III) subphthalocyanines 5-8 with six lipophilic alkylthio chains at the peripheral sites, bearing hydroxy or triethylsilyloxy groups in the axial position, have been synthesized and their thermotropic properties have been studied. These compounds are gelatinous materials at room temperature and gradually soften as the temperature is raised up to a point at which high fluidity typical of classical liquids is observed. By the usual techniques employed for the study of thermotropic behaviour (polarizing microscopy, DSC and X-ray diffraction), no liquid crystalline properties have been found. Instead, the compounds have an amorphous structure (i.e. behave as isotropic materials) throughout the temperature range studied. They could be designated as liquid subphthalocyanines.

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Section: Synthesis and Spectroscopic Characterizationsupporting

confidence: 73%

Synthesis and thermotropic properties of hydroxy and silyloxy axially substituted phthalocyanines

Rey

Martínez‐Díaz

Barberá

et al. 2000

J. Porphyrins Phthalocyanines

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“…The dihydroxyporphinatogermanium(IV), (HO)2Ge(P), used in the x-ray crystallographic structure determination was prepared according to published procedures. 1 Well formed purple crystals exhibiting a rectangular-prismatic morphology of (MeOkGefP) were obtained by allowing methanol to diffuse into a nearly saturated solution of (HOkGeiP) in chloroform. The structure determination of crystals grown in this manner showed that the (HOkGefP) had been converted to (MeO)2Ge(P) during the crystallization process.2 Preliminary x-ray studies of a single crystal of (MeO)2Ge(P) using photographic and diffractometric methods showed the crystal system to be monoclinic and systematic absences fixed the space group to be P2\/c.…”

Section: Methodsmentioning

confidence: 99%

Crystal and molecular structure of dimethoxyporphinato-germanium(IV)

Mavridis¹,

Tulinsky²

1976

Inorg. Chem.

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The crystal and molecular structure of dimethoxyporphinatogermanium(IV), (MeOkGeCP), has been determined by x-ray crystallographic methods. The compound crystallizes in the monoclinic system, a = 15.013 (5), b = 14.441 (5), c = 8.414 (4) Á., ß = 91.85 (2)°, space group P2\/c with four molecules per unit cell. The structure was solved through the application of Sayre's equation. The crystal structure is unusual in that the asymmetric unit consists of two crystallographically independent half-molecules located at centers of symmetry. The germanium coordination corresponds to that of a slightly distorted octahedron with the methoxy groups in apical positions. The averaged structures of the independent molecules are the same except for the orientation of the methoxy groups and the structures closely approximate Duh symmetry. The independent pyrrole rings have a geometry similar to that of the azapyrrole of free base porphine and there is a general "squaring-up" and overall contraction of the central core region of (MeOhGeCP) compared to the free base. The density of (MeO)2Ge(P) is the largest of all porphyrins, especially when normalized with respect to the central ion. The abnormally large density is probably due to the fact that the molecular centers are located at face centered positions so that the packing is based upon a close packed arrangement.

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“…Also, for the low-spin NP2-NMeIm species we have taken the z-axis to be along the His NE2-Fe vector, and have used the principle of counter-rotation of the g-tensor with rotation of the His57 imidazole plane to determine the orientation of g xx and g yy . 49 In two seminal papers by Emerson and La Mar, 31–32 they used the magnetic anisotropies as predicted by Horrocks and Greenberg 45 for the study of metMb-CN in terms of off-axis binding of the cyanide ion, and fit the pseudocontact shifts of a number of amino acid side chains near the heme, to an approximate 15° off-axis tilt of the z-axis toward the meso -δ carbon, which coincided with the similar off-axis tilt of CO in the Mb-CO structure, 79 which was isostructural with metMb-CN. 32 This approach cannot be applied to the present case because of: 1) the lack of a crystal structure for a NP-NMeIm complex, and 2) the lack of assignments of protein resonances (others than those from His57) in the diamagnetic NO-bound form of NP2.…”

Section: Resultsmentioning

confidence: 94%

Electron Spin Density on the Axial His Ligand of High-Spin and Low-Spin Nitrophorin 2 Probed by Heteronuclear NMR Spectroscopy

et al. 2013

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The electronic structure of heme proteins is exquisitely tuned by the interaction of the iron center with the axial ligands. NMR studies of paramagnetic heme systems have been focused on the heme signals, but signals from the axial ligands have been rather difficult to detect and assign. We report an extensive assignment of the 1H, 13C and 15N resonances of the axial His ligand in the NO-carrying protein nitrophorin 2 (NP2) in the paramagnetic high-spin and low-spin forms, as well as in the diamagnetic NO complex. We find that the high-spin protein has σ spin delocalization to all atoms in the axial His57, which decreases in size as the number of bonds between Fe(III) and the atom in question increase, except that within the His57 imidazole ring the contact shifts are a balance between positive σ and negative π contributions. In contrast, the low-spin protein has π spin delocalization to all atoms of the imidazole ring. Our strategy, adequately combined with a selective residue labeling scheme, represents a straightforward characterization of the electron spin density in heme axial ligands.

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Germanium porphines and some silicon and germanium phthalocyanines

Cited by 32 publications

References 6 publications

Synthesis and thermotropic properties of hydroxy and silyloxy axially substituted phthalocyanines

Synthesis and thermotropic properties of hydroxy and silyloxy axially substituted phthalocyanines

Crystal and molecular structure of dimethoxyporphinato-germanium(IV)

Electron Spin Density on the Axial His Ligand of High-Spin and Low-Spin Nitrophorin 2 Probed by Heteronuclear NMR Spectroscopy

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