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1.
The first examples of β–β directly linked, acetylene‐bridged, and butadiyne‐bridged 5,15‐diazaporphyrin dimers have been prepared by palladium‐catalyzed coupling reactions of nickel(II) and copper(II) complexes of 3‐bromo‐10,20‐dimesityl‐5,15‐diazaporphyrin (mesityl=2,4,6‐trimethylphenyl). The effects of the linking modes and meso‐nitrogen atoms on the structural, optical, electrochemical, and magnetic properties of the distributed π systems were investigated by using X‐ray crystallography, UV/Vis absorption spectroscopy, DFT calculations, cyclic voltammetry, and ESR spectroscopy. Both the electronic and steric effects of the meso‐nitrogen atoms play an important role in the highly coplanar geometry of the directly linked dimers. The direct β–β linkage produces enhanced π conjugation and electron‐spin coupling between the two diazaporphyrin units.  相似文献   

2.
《化学:亚洲杂志》2017,12(7):816-821
NH‐bridged and pyrazine‐fused metallodiazaporphyrin dimers have been prepared from nickel(II) and copper(II) complexes of 3‐amino‐5,15‐diazaporphyrin by Pd‐catalyzed C−N cross‐coupling and oxidative dimerization reactions, respectively. The synergistic effects of the nitrogen bridges and meso ‐nitrogen atoms play major roles in enhancing the light‐harvesting properties and delocalization of an electron spin over the entire π‐skeletons of the metallodiazaporphyrin dimers.  相似文献   

3.
The present paper reports the first comprehensive study on the synthesis, structures, optical and electrochemical properties, and peripheral functionalizations of nickel(II) and copper(II) complexes of β‐unsubstituted 5,15‐diazaporphyrins (M‐DAP; M=Ni, Cu) and pyridazine‐fused diazacorrinoids (Ni‐DACX; X=N, O). These two classes of compounds were constructed starting from mesityldipyrromethane by a metal–template method. Ni‐DAP and Cu‐DAP were prepared in high yields by the reaction of the respective metal–bis(dibromodipyrrin) complexes with NaN3–CuX (X=I, Br), whereas Ni‐DACN and Ni‐DACO were formed as predominant products by the reaction with NaN3. In both cases, the metal centers change their geometry from tetrahedral to square planar during the aza‐annulation; X‐ray crystallographic analyses of M‐DAPs showed highly planar diazaporphyrin π planes. The Q band of Ni‐DAP was redshifted and intensified compared with that of a nickel–porphyrin reference, due to the involvement of electronegative nitrogen atoms at the meso positions. It was found that the peripheral bromination of Ni‐DAP and Ni‐DACO occurred regioselectively to afford Ni‐DAP‐Br4 and Ni‐DACO‐Br, respectively. These brominated derivatives underwent Stille reactions with tributyl(phenyl)stannane to give the corresponding phenylated derivatives, Ni‐DAP‐Ph4 and Ni‐DACO‐Ph. On the basis of the absorption spectra and X‐ray analysis, it has been concluded that the attached phenyl groups efficiently conjugate with the diazaporphyrin π system. The present results unambiguously corroborate that the β‐unsubstituted DAPs and DACXs are promising platforms for the development of a new class of π‐conjugated azaporphyrin‐based materials.  相似文献   

4.
3‐Pyridyl‐5,15‐diazaporphyrin nickel(II) serves as a bidentate metalloligand for platinum(II), ruthenium(II), and rhenium(I) metal centers. Single‐crystal X‐ray diffraction analysis of these metal complexes unambiguously reveals the presence of a dative bond between the outer metal center and the meso‐nitrogen atom. The UV/Vis absorption spectra of the complexes show substantially red‐shifted bands which are perturbed by outer‐metal coordination. This is due to the contribution of metal‐to‐ligand charge transfer interactions.  相似文献   

5.
A set of 5,15‐biphenylene‐bridged porphyrin wheels, namely, [n]cyclo‐5,15‐porphyrinylene‐4,4′‐biphenylenes [n]CPB , have been synthesized through the platination of 5,15‐bis(4‐(pinacolboranyl)phenyl) nickel(II) porphyrin and subsequent reductive elimination of PtII(cod)‐bridged cyclic porphyrin intermediates. The calculated strain energies for [3]CPB , [4]CPB , [5]CPB , and [6]CPB are 49.3, 32.9, 23.5, and 16.0 kcal mol?1, respectively. UV/Vis absorption spectra and cyclic voltammetry indicated characteristic ring‐size‐dependent absorption‐peak shifts and redox‐potential shifts, which presumably reflect the degree of strain in the π‐systems. Excitation‐energy hopping (EEH) times were determined to be 5.1, 8.0, 8.0, and 9.6 ps for [3]CPB , [4]CPB , [5]CPB , and [6]CPB , respectively, in a pump‐power‐dependent TA experiment.  相似文献   

6.
The first comprehensive study of the synthesis and structure–property relationships of 2,2′‐bis(benzo[b]phosphole)s and 2,2′‐benzo[b]phosphole–benzo[b]heterole hybrid π systems is reported. 2‐Bromobenzo[b]phosphole P‐oxide underwent copper‐assisted homocoupling (Ullmann coupling) and palladium‐catalyzed cross‐coupling (Stille coupling) to give new classes of benzo[b]phosphole derivatives. The benzo[b]phosphole–benzo[b]thiophene and ‐indole derivatives were further converted to P,X‐bridged terphenylenes (X=S, N) by a palladium‐catalyzed oxidative cycloaddition reaction with 4‐octyne through the Cβ? H activation. X‐ray analyses of three compounds showed that the benzo[b]phosphole‐benzo[b]heterole derivatives have coplanar π planes as a result of the effective conjugation through inter‐ring C? C bonds. The π–π* transition energies and redox potentials of the cis and trans isomers of bis(benzo[b]phosphole) P‐oxide are very close to each other, suggesting that their optical and electrochemical properties are little affected by the relative stereochemistry at the two phosphorus atoms. The optical properties of the benzo[b]phosphole–benzo[b]heterole hybrids are highly dependent on the benzo[b]heterole subunits. Steady‐state UV/Vis absorption/fluorescence spectroscopy, fluorescence lifetime measurements, and theoretical calculations of the non‐fused and acetylene‐fused benzo[b]phosphole–benzo[b]heterole π systems revealed that their emissive excited states consist of two different conformers in rapid equilibrium.  相似文献   

7.
A reaction sequence of regioselective peripheral bromination, Suzuki–Miyaura coupling with 2‐borylated thiophene or pyrrole, and oxidative ring‐closure with FeCl3 allowed the synthesis of heterole‐fused earring porphyrins 4Pd and 9Pd from the parent earring porphyrin 1 . Differently pyrrole‐fused porphyrins 5H and 6H and their PdII complexes 5Pd and 6Pd were also synthesized. The structures of 4Pd , 5H, 6Pd , and 8Pd have been revealed by X‐ray analysis to be slightly twisted owing to constraints imposed by heterole‐fused structures. 5Pd exhibits an intensified band at 1505 nm, while 4Pd and 9Pd display small but remarkably red‐shifted absorption bands reaching around 2200 nm.  相似文献   

8.
The first examples of air‐stable 20π‐electron 5,10,15,20‐tetraaryl‐5,15‐diaza‐5,15‐dihydroporphyrins, their 18π‐electron dications, and the 19π‐electron radical cation were prepared through metal‐templated annulation of nickel(II) bis(5‐arylamino‐3‐chloro‐8‐mesityldipyrrin) complexes followed by oxidation. The neutral 20π‐electron derivatives are antiaromatic and the cationic 18π‐electron derivatives are aromatic in terms of the magnetic criterion of aromaticity. The meso N atoms in these diazaporphyrinoids give rise to characteristic redox and optical properties for the compounds that are not typical of isoelectronic 5,10,15,20‐tetraarylporphyrins.  相似文献   

9.
A reaction sequence of regioselective peripheral bromination, Suzuki–Miyaura coupling with 2‐borylated thiophene or pyrrole, and oxidative ring‐closure with FeCl3 allowed the synthesis of heterole‐fused earring porphyrins 4Pd and 9Pd from the parent earring porphyrin 1 . Differently pyrrole‐fused porphyrins 5H and 6H and their PdII complexes 5Pd and 6Pd were also synthesized. The structures of 4Pd , 5H, 6Pd , and 8Pd have been revealed by X‐ray analysis to be slightly twisted owing to constraints imposed by heterole‐fused structures. 5Pd exhibits an intensified band at 1505 nm, while 4Pd and 9Pd display small but remarkably red‐shifted absorption bands reaching around 2200 nm.  相似文献   

10.
A useful parameter describing magnetic coupling interactions has been inspected in transition metal dimers, in which two transition metal ions are bridged by extended bis‐bidentate ligands. This parameter is the square of overlap integral between the spatial parts of magnetic orbitals in the broken symmetry state. The oxalato‐bridged Cu (II) dimers, in which the Cu (II) atom is either in tetrahedral or square pyramid coordination environment, have been calculated with the density functional theory coupling the broken symmetry approach. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2003  相似文献   

11.
Conjugated polymers consisting of pyrrole or an N‐substituted pyrrole bridged by methine with a mesogenic group were synthesized. Chemical structures of the products were confirmed with IR, NMR, UV–visible (UV–vis) spectroscopy, and gel permeation chromatography analysis. Liquid crystallinity was examined with differential scanning calorimetry measurements and polarizing optical microscopy observations. Liquid crystal domains of the polymer were macroscopically oriented in one direction by an external magnetic force (10 Tesla). The polymer orientation was confirmed by optical microscopy and X‐ray analysis. One of the polymers exhibited a striated fan‐shaped texture when observed with a polarizing optical microscope. This is attributed to the formation of a chiral smectic C (SmC*) phase, which is a property of ferroelectricity. Spontaneous polarization of the polymer occurred at 110 nC/cm2. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 616–629, 2005  相似文献   

12.
The title isomers, namely 3‐chloro‐N‐[1‐(1H‐pyrrol‐2‐yl)ethylidene]aniline, (I), and 4‐chloro‐N‐[1‐(1H‐pyrrol‐2‐yl)ethylidene]aniline, (II), both C12H11ClN2, differ in the position of the chlorine substitution. Both compounds have the basic iminopyrrole structure, which shows a planar backbone with similar features. The dihedral angle formed by the planes of the pyrrole and benzene rings is 75.65 (7)° for (I) and 86.56 (8)° for (II). The H atom bound to the pyrrole N atom is positionally disordered and partial protonation occurs at the imino N atom in (I), while this phenomenon is absent from the structure of (II). Packing interactions for both compounds include intermolecular N—H...N hydrogen bonds and C—H...π interactions, forming centrosymmetric dimers for both (I) and (II).  相似文献   

13.
We report the synthesis and characterisation of new examples of meso‐hydroxynickel(II) porphyrins with 5,15‐diphenyl and 10‐phenyl‐5,15‐diphenyl/diaryl substitution. The OH group was introduced by using carbonate or hydroxide as nucleophile by using palladium/phosphine catalysis. The NiPor?OHs exist in solution in equilibrium with the corresponding oxy radicals NiPor?O.. The 15‐phenyl group stabilises the radicals, so that the 1H NMR spectra of {NiPor?OH} are extremely broad due to chemical exchange with the paramagnetic species. The radical concentration for the diphenylporphyrin analogue is only 1 %, and its NMR line‐broadening was able to be studied by variable‐temperature NMR spectroscopy. The EPR signals of NiPor?O. are consistent with somewhat delocalised porphyrinyloxy radicals, and the spin distributions calculated by using density functional theory match the EPR and NMR spectroscopic observations. Nickel(II) meso‐hydroxy‐10,20‐diphenylporphyrin was oxidatively coupled to a dioxo‐terminated porphodimethene dyad, the strongly red‐shifted electronic spectrum of which was successfully modelled by using time‐dependent DFT calculations.  相似文献   

14.
Two novel homoleptic diazaporphyrinato lanthanide sandwich com-plexes M(2)(DAP)(3) [M = Ce (1), Eu (2); DAP= 2,8,12,18-tetra-ethyl-3,7,13,17-tetramethyl-5,15-diazaporphyrinate] were synthesized by a one-pot reaction of the corresponding M(acac)(3).nH(2)O (acac = acetylacetonate) with metal-free D(2)(h) type diazaporphyrin, H(2)DAP. The spectroscopic and electrochemical properties are compared with those of complexes based on D(4)(h) symmetry porphyrin ligands.  相似文献   

15.
The title compounds, rac‐(1′R,2R)‐tert‐butyl 2‐(1′‐hydroxyethyl)‐3‐(2‐nitrophenyl)‐5‐oxo‐2,5‐dihydro‐1H‐pyrrole‐1‐carboxylate, C17H20N2O6, (I), rac‐(1′S,2R)‐tert‐butyl 2‐[1′‐hydroxy‐3′‐(methoxycarbonyl)propyl]‐3‐(2‐nitrophenyl)‐5‐oxo‐2,5‐dihydro‐1H‐pyrrole‐1‐carboxylate, C20H24N2O8, (II), and rac‐(1′S,2R)‐tert‐butyl 2‐(4′‐bromo‐1′‐hydroxybutyl)‐5‐oxo‐2,5‐dihydro‐1H‐pyrrole‐1‐carboxylate, C13H20BrNO4, (III), are 5‐hydroxyalkyl derivatives of tert‐butyl 2‐oxo‐2,5‐dihydropyrrole‐1‐carboxylate. In all three compounds, the tert‐butoxycarbonyl (Boc) unit is orientated in the same manner with respect to the mean plane through the 2‐oxo‐2,5‐dihydro‐1H‐pyrrole ring. The hydroxyl substituent at one of the newly created chiral centres, which have relative R,R stereochemistry, is trans with respect to the oxo group of the pyrrole ring in (I), synthesized using acetaldehyde. When a larger aldehyde was used, as in compounds (II) and (III), the hydroxyl substituent was found to be cis with respect to the oxo group of the pyrrole ring. Here, the relative stereochemistry of the newly created chiral centres is R,S. In compound (I), O—H...O hydrogen bonding leads to an interesting hexagonal arrangement of symmetry‐related molecules. In (II) and (III), the hydroxyl groups are involved in bifurcated O—H...O hydrogen bonds, and centrosymmetric hydrogen‐bonded dimers are formed. The Mukaiyama crossed‐aldol‐type reaction was successful when using the 2‐nitrophenyl‐substituted hydroxypyrrole, or the unsubstituted hydroxypyrrole, and boron trifluoride diethyl ether as catalyst. The synthetic procedure leads to a syn configuration of the two newly created chiral centres in all three compounds.  相似文献   

16.
The crystal and mol­ecular structures of 4‐ethyl‐3,5‐dimethyl­pyrrole‐2‐carbaldehyde, C10H15NO, (I), benzyl 3,5‐dimethyl­pyrrole‐2‐carboxyl­ate, C14H15NO2, (II), benzyl 4‐acetyl‐3,5‐dimethyl­pyrrole‐2‐carboxyl­ate, C16H17NO3, (III), dimethyl 3,5‐dimethyl­pyrrole‐2,4‐dicarboxyl­ate, C10H13NO4, (IV), 4‐ethyl‐3,5‐dimethyl‐2‐(p‐tos­ylacet­yl)pyrrole, C17H21NO3S, (V), and ethyl 4‐(2‐ethoxy­carbonyl‐2‐hydroxy­acrylo­yl)‐3,5‐dimethyl­pyrrole‐2‐carboxyl­ate, C15H19NO6, (VI), were determined at 130 K. Compounds (I), (II), (IV), (V) and (VI) form hydrogen‐bonded dimers [N—H⋯O=C = 1.97 (2)–2.03 (3) Å]. Four dimers, viz. (I) and (IV)–(VI), have inversion symmetry, while the dimer of (II) has twofold symmetry. Only (III) forms polymeric chains involving hydrogen bonds between the pyrrole H atom and the acetyl carbonyl group [H⋯O = 1.97 (2) Å] and is further stabilized by CH3⋯O inter­actions (C—H⋯O = 2.28–2.49 Å). Compound (VI) was found to occur as the enol ether in the crystal.  相似文献   

17.
Acetylene and trans‐ethylene bridged BIII‐subporphyrin dimers were synthesized by cross‐coupling reactions of meso‐bromo BIII subporphyrin. These dimers display perturbed and red‐shifted absorption spectra reaching around 750 nm and fluorescence reaching at around 850 nm with high quantum yields of 0.39 and 0.47, respectively. DFT calculations have revealed that the HOMOs and the LUMOs of both dimers are spread over the two subporphyrin units as an indication of effective conjugation between the two subporphyrin units. The large Stokes shifts and characteristic pico‐second time‐resolved transient absorption spectra indicated that the S1‐states of the dimers relax with structural changes, which are larger for the trans‐ethylene bridged dimer.  相似文献   

18.
A series of perylene‐3,4,9,10‐bis(dicarboximide) (PDI) dimers linked through the bay regions was systematically synthesized to examine the electronic structures and photophysical properties in dependence on the distance and orientation between the two PDI units. The spectroscopic and electrochemical measurements suggested that the coupling value of a directly linked PDI dimer (PDI)2 is much larger than those of para‐ and meta‐phenylene‐bridged PDI dimers p‐(PDI)2 and m‐(PDI)2. The width of Davydov splitting was quantitatively evaluated to compare the coupling values between the two PDI units in these dimers by absorption spectroscopy in frozen 2‐methyl‐THF. Excimer formation of PDI dimers induced the strong fluorescence quenching and large red‐shifts. Femtosecond transient absorption revealed a broad absorption derived from an excimer in the range from about 600 nm to the near‐IR region. The rate constants of formation and decay of the excimer are strongly dependent on the coupling values. Time‐resolved measurements on ferrocene‐linked p‐(PDI)2 revealed a competition between the photoinduced processes of electron transfer and excimer formation in PhCN, which is in sharp contrast with the sole electron‐transfer process in toluene.  相似文献   

19.
合成了四种齐聚噻吩衍生物:5,5"-二氰基-2,2’:5’,2"-三噻吩 (DCN3T), 5,5"’-二氰基-2,2’:5’,2":5",2"’-四噻吩 (DCN4T), 5,5"’-甲氧基-2,2’:5’,2":5",2"’-四噻吩(DMO4T) 和 4,4"-二羧基-5,5"-二丙基-2,2’:5’,2"-三噻吩 (BP3T-DCOOH),研究了它们的电致变色性质,研究结果发现,这四种齐聚噻吩衍生物膜在电场作用下,可以发生可逆的颜色变化。  相似文献   

20.
A series of soluble carbonyl‐bridged heterotriangulenes, in which flexible n‐dodecyl chains are attached through different spacers to the planar nitrogen‐centered polycyclic core, have been synthesized. The introduction of triisopropylsilylethynyl moieties enabled, for the first time, the characterization of single‐crystal columnar packing of a substituted heterotriangulene by X‐ray crystallography. Electrochemical studies disclosed the carbonyl‐bridged heterotriangulene core as a reasonably strong acceptor for a reversible two‐electron transfer. The tendency of substituted heterotriangulenes to self‐assemble in solution, on surfaces, and in the bulk appeared to sensitively depend on the nature of the lateral substituents, their steric demand, and the applied solution processing conditions. It can be concluded that 1) additional phenylene moieties between the heterotriangulene core and the n‐dodecyl chains facilitate self‐assembly by extending the π‐conjugated polycyclic disc, 2) the rod‐like ethynylene spacers introduce some additional flexibility and hence lower the overall aggregation tendency, and 3) the combination of both features in the phenylene–ethynylene moieties induces thermotropic liquid crystallinity.  相似文献   

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