Macrocyclic Ligand Design. A Large Covalently-Linked Ring System Incorporating Four Cyclam Units and its Interaction with Nickel(II), Copper(II), Zinc(II), and Cadmium(II)

2009 ◽  
Vol 62 (10) ◽  
pp. 1207 ◽  
Author(s):  
Ying Dong ◽  
Leonard F. Lindoy
Keyword(s):  
Solid State ◽  
Macrocyclic Ligand ◽  
Ligand Design ◽  
Spectrophotometric Titration ◽  
Ring System ◽  
Electrochemical Studies ◽  
Amine Group ◽  
High Dilution ◽  
Coordination Behaviour ◽  
Covalently Linked

A cyclic, tetra-linked macrocyclic species incorporating four 1,4,8,11-tetraazacyclotetradecane (cyclam) subunits has been synthesized employing Boc amine-group protecting chemistry coupled with high dilution conditions for the cyclization step. A series of 4:1 (metal:ligand (M:L)) complexes with nickel(ii), copper(ii), zinc(ii), and cadmium(ii) has been synthesized. Visible spectophotometric (including spectrophotometric titration), EPR, NMR, and electrochemical studies are reported for individual complexes and are in general accord with similar 4:1 (M:L) coordination behaviour occurring in both the solid state and in solution. The study makes available an example of a new category of large cyclic receptors whose cavity can be tuned electronically through variation of the metal centres incorporated in the cavity walls.

Synthesis and properties of covalently linked di-p-benzihomoporphyrin-BODIPY conjugates

2021 ◽  
pp. A-I
Author(s):  
Rima Sengupta ◽  
Shubham Tiwari ◽  
Mangalampalli Ravikanth
Keyword(s):  
Individual Characteristic ◽  
Electrochemical Studies ◽  
Dft Studies ◽  
Coupling Condition ◽  
Meso Position ◽  
Acid Catalyzed ◽  
Characteristic Features ◽  
Covalently Linked ◽  
Mild Acid ◽  
Spectral And Electrochemical Studies

Two mono meso-functionalized [20]di-[Formula: see text]-benzihomoporphyrins containing [Formula: see text]-formylphenyl and [Formula: see text]-iodophenyl groups at meso-position respectively were synthesized by condensing one equivalent of appropriate tetrapyrrane with one equivalent of [Formula: see text]-formyl benzaldehyde/[Formula: see text]-iodo benzaldehyde in CH2Cl2 under mild acid catalyzed conditions. The meso-formylphenyl and meso-iodophenyl functionalized di-[Formula: see text]-benzihomoporphyrins were used to synthesize two covalently linked di-[Formula: see text]-benzihomoporphyrins-BODIPY conjugates. The meso-formylphenyl-functionalized di-[Formula: see text]-benzihomoporphyrin was converted to corresponding meso-dipyrrolyl substituted di-[Formula: see text]-benzihomoporphyrin by treating with excess pyrrole under acid catalyzed conditions. In the next step, the meso-dipyrrolyl di-[Formula: see text]-benzihomoporphyrin was subjected to oxidation followed by BF2 complexation to afford the directly linked di-[Formula: see text]-benzihomoporphyrin-BODIPY conjugate. The meso-iodophenyl functionalized di-[Formula: see text]-benzihomoporphyrin was coupled with ethynyl-functionalized BODIPY under mild Pd(0) coupling condition to synthesize diphenylethyne-bridged di-[Formula: see text]-benzihomoporphyrin-BODIPY conjugate. The two conjugates were characterized by HR-MS, NMR, absorption, electrochemical, fluorescence and DFT studies. The spectral and electrochemical studies indicated that the two constituents, di-[Formula: see text]-benzihomoporphyrin and BODIPY units in the conjugates interact weakly and retain their individual characteristic features. DFT studies indicated a possibility of charge transfer between di-[Formula: see text]-benzihomoporphyrin and BODIPY units in conjugates.

Solid State Structure and Photoluminescence properties of poly(2,5-dialkoxy-p-phenyleneethynylene)s

1995 ◽  
Vol 413 ◽  
Author(s):  
Christoph Weder ◽  
Michael J. Wagner ◽  
Mark S. Wrighton
Keyword(s):  
Solid State ◽  
Long Range ◽  
Photophysical Properties ◽  
Significant Degree ◽  
Range Order ◽  
Quantum Yields ◽  
Side Chains ◽  
Long Range Order ◽  
Rigid Rod ◽  
Covalently Linked

ABSTRACTIn an effort to better understand the relationship between molecular structure and photophysical properties, we have prepared and investigated a series of novel poly(2,5-dialkoxy-p-phenyleneethynylene)s. Wide angle X-ray diffraction measurements show that the supramolecular structure can be easily and significantly influenced by the nature of substituents covalently linked to the rigid-rod polymer main chains. Polymers which have sterically hindered side chains are essentially amorphous, while those with only linear side chains can form lamellar structures with a significant degree of long-range order. High photoluminescence quantum yields, up to 0.86 in solution and 0.36 in the solid state, have been measured. While the solution quantum yields are independent of the functionalization, solid state quantum efficiencies were found to be related to the degree of long-range order in the samples. In samples with a high degree of long-range order, the close proximity of the coplanar oriented polymer backbones is assumed to lead to the formation of eximer complexes which provide non emissive decay channels and, hence, result in comparable low photoluminescence quantum yields. In samples that adopt only a small extent of long-range order, the rigid-rod conjugated polymer backbones behave as if they were ‘dissolved’ in a hydrocarbon solvent and consequently high quantum efficiencies are obtained. Preliminary results indicate the suitability of these polymers as the emitting layer in electroluminescent devices.

Tosylate salts of the anticancer drug lapatinib

2013 ◽  
Vol 69 (12) ◽  
pp. 1516-1523 ◽  
Author(s):  
K. Ravikumar ◽  
B. Sridhar ◽  
Jagadeesh Babu Nanubolu ◽  
A. K. S. Bhujanga Rao ◽  
R. Jyothiprasad
Keyword(s):  
Solid State ◽  
Hydrogen Bonds ◽  
Physicochemical Properties ◽  
Anticancer Drug ◽  
Ring System ◽  
Nonbonded Interactions ◽  
One Dimensional ◽  
Drug Products ◽  
Ring Motif

Two tosylate salts of an anticancer drug lapatinib,viz. a monotosylate [systematic name: ({5-[4-({3-chloro-4-[(3-fluorophenyl)methoxy]phenyl}amino)quinazolin-6-yl]furan-2-yl}methyl)[2-(methylsulfonyl)ethyl]azanium 4-methylbenzenesulfonate], C29H27ClFN4O4S+·C7H7O3S−, (I), and a ditosylate [systematic name: 4-({3-chloro-4-[(3-fluorophenyl)methoxy]phenyl}amino)-6-]5-({[2-(methylsulfonyl)ethyl]azaniumyl}methyl)furan-2-yl[quinazolin-1-ium bis(4-methylbenzenesulfonate)], C29H28ClFN4O4S2+·2C7H7O3S−, (II), were obtained during crystallization attempts for polymorphism. In both structures, the lapatinib cation is in a distorted U-like conformation and the tosylate anion is clamped between the aniline N atom and methylamine N atom through N—H...O hydrogen bonds, forming anR22(15) ring motif. The 4-anilinoquinazoline ring system is essentially planar in (I), while it is twisted in (II), controlled by an intramolecular C—H...N interaction. In (I), alternating cations and anions are linked by N—H...O hydrogen bonds intoC22(6) chains. These chains are linked by cations in a helical manner. The presence of the additional tosylate anion in (II) results in the formation of one-dimensional tapes of fused hydrogen-bonded rings through N—H...O and C—H...O interactions. These studies augment our understanding of the role of nonbonded interactions in the solid state, which is useful for correlation to the physicochemical properties of drug products.

Solid state electrochemiluminescence from homogeneous and patterned monolayers of bifunctional spirobifluorene

2018 ◽  
Vol 54 (39) ◽  
pp. 4999-5002 ◽  
Author(s):  
Sergej Kudruk ◽  
Elena Villani ◽  
Federico Polo ◽  
Sebastian Lamping ◽  
Martin Körsgen ◽  
...  
Keyword(s):  
Solid State ◽  
Self Assembled Monolayers ◽  
Assembled Monolayers ◽  
Self Assembled ◽  
Covalently Linked

Electrochemiluminescence (ECL) from self-assembled monolayers of a spirobifluorene dye covalently linked to a transparent ITO surface is reported.

scholarly journals A ferrocene redox-active triazolium macrocycle that binds and senses chloride

2012 ◽  
Vol 8 ◽  
pp. 246-252 ◽  
Author(s):  
Nicholas G White ◽  
Paul D Beer
Keyword(s):  
Solid State ◽  
Good Yield ◽  
Electrochemical Studies ◽  
Nmr Titration ◽  
X Ray ◽  
X Ray Crystallography ◽  
H Nmr ◽  
Redox Active

A ferrocene bis(triazole) macrocycle was synthesised in good yield by the Eglinton coupling of an acyclic bis(alkyne) precursor and characterised in the solid state by X-ray crystallography. Alkylation gives the corresponding triazolium macrocycle, which binds chloride and benzoate strongly in CD3CN solution through favourable charge-assisted C–H···anion interactions, as evidenced by 1H NMR titration experiments. Preliminary electrochemical studies reveal that the redox-active macrocycle is capable of sensing chloride in CH3CN solution.

Ring inversion in solid fluorocyclohexane

1986 ◽  
Vol 64 (10) ◽  
pp. 2094-2095 ◽  
Author(s):  
Roderick E. Wasylishen
Keyword(s):  
Solid State ◽  
Gas Phase ◽  
Solid Phase ◽  
Ring System ◽  
Cyclohexane Ring ◽  
Ring Inversion ◽  
Nmr Study

Inversion of the cyclohexane ring system in the solid state has been directly observed in a 19F nmr study of solid fluorocyclohexane. The barrier to ring inversion in the orientationally disordered solid phase, ΔG≠e→a = 44.1 ± 0.9 kJ mol−1 at 263 K is found to be only slightly larger than the value previously reported for a CFCl3 solution of fluorocyclohexane. The population of the equatorial conformation is slightly favored over the axial conformation with K = Pe/Pa = 1.56 at 281 K; similar values have been obtained in CFCl3 and in the gas phase.

Erste strukturelle Charakterisierung eines leicht oxidierbaren 1,4-Dihydrochinoxalin-Derivats / First Structural Characterization of an Easily Oxidized Derivative of 1,4-Dihydroquinoxaline

1993 ◽  
Vol 48 (6) ◽  
pp. 713-718 ◽  
Author(s):  
Alexander Lichtblau ◽  
Hans-Dieter Hausen ◽  
Wolfgang Kaim
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Dihedral Angle ◽  
Structural Characterization ◽  
Crystal Structure Analysis ◽  
Ring System ◽  
Structural Flexibility ◽  
Steric Repulsion ◽  
Alkyl Groups

The first crystal structure analysis of a 1,4-dihydroquinoxaline is described by example of the 1,4-bis(tert-butyldimethylsilyl) derivative. In the solid state, this molecule exhibits a nonplanar heterocycle with a dihedral angle of 156.3° along the N—N axis in the boat-shaped 8π electron ring system. The alkyl groups of the Si(tert-Bu)Me2 substituents are arranged as to minimize steric repulsion. Despite the reduced π electron conjugation due to non-planarity, the compound is oxidized reversibly to an EPR detectable radical cation at —0.59 V vs. ferrocene in dichloromethane. However, the second oxidation to the fully aromatic dication is electrochemically irreversible. A comparison with previously obtained results illustrates the structural flexibility of the non-aromatic 1,4-dihydro-1,4-diazine ring system which is strongly affected by rather weak non-bonded interactions.

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