bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mast cells are required for optimal autoreactive T cell responses in a murine model of multiple sclerosis
Authors: Gregory Gregory D. , Robbie‐Ryan Michaela , Secor Virginia H. , Sabatino Joseph J. , Brown Melissa A. 
Published: November 2005

AbstractOnce considered to be of sole importance in allergy and parasitic infections, the role of mast cells in other pathologic and protective immune responses is becoming increasingly evident. We previously demonstrated that mast cells contribute to the severity of EAE, the rodent model of multiple sclerosis. Here we show that one mode of mast cell action is through effects on the autoreactive T cell response. Early indices of both peripheral CD4 and CD8 T cell activation, including IFN‐γ production and increases in CD44 and CD11a expression, are attenuated in mast cell‐deficient (W/Wv) mice after myelin oligodendrocyte glycoprotein35–55 priming when compared to WT animals. Reduced infiltrates of activated T cells in the central nervous system are also observed. Importantly, selective repletion of the mast cell compartment restores most T cell responses in the lymph nodes and the central nervous system, correlating with reconstitution of severe disease. The adoptive transfer of WT‐derived encephalitogenic T cells results in significantly less severe disease in W/Wv recipients, indicating that mast cells also exert potent effects after the initial T cell response is generated. Our data provide the first in vivo evidence that mast cells can significantly influence T cell responses and suggest that mast cells exacerbate disease during both the inductive and effector phases.
Synthesis of Main Group Polycations in Molten and Pseudo‐Molten GaBr3 Media
Authors: Kuznetsov Alexei N. , Popovkin Boris A. , Ståhl Kenny , Lindsjö Martin , Kloo Lars 
Published: November 2005

AbstractThe prospects of synthesizing polycationic species using GaBr3 in benzene solution at room temperature have been investigated. The salts Bi8[GaBr4]2, Sb8[GaBr4]2 and Te4[Ga2Br7]2 have been isolated and characterized. The first two compounds are isotypic with Sb8[GaCl4]2, crystallize in the space group Pna21, and feature square anti‐prismatic E82+ polycations (E = Sb, Bi). Unit‐cell parameters for Bi8[GaBr4]2 are a = 18.3014(10) Å, b = 10.3391(6) Å and c = 13.5763(7) Å, and for Sb8[GaBr4]2; a = 18.096(2) Å, b = 10.1572(9) Å and c = 13.2168(10) Å. Te4[Ga2Br7]2 crystallizes in the space group P21/c with a = 10.1600(9) Å, b = 10.8314(9) Å, c = 13.8922(10) Å and β = 99.182(7)°, and features a square‐planar Te42+ polycation. The compound Bi5[GaBr4]3 has been synthesized from molten GaBr3 and characterized by using powder diffractometry in space group Fm‐3c; a = 17.6263(8) Å. The structure model for this compound suggests the included Bi53+ cations to be practically freely oriented within its cavities in the solid phase. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Synthesis and Characterization of Two Novel, Mono‐Lacunary Dawson Polyoxometalate‐Based, Water‐Soluble Organometallic Ruthenium(II) Complexes: Molecular Structure of [{(C6H6)Ru(H2O)}(α2‐P2W17O61)]8–
Authors: Sakai Yoshitaka , Shinohara Akira , Hayashi Kunihiko , Nomiya Kenji 
Published: November 2005

AbstractThe synthesis and structural characterization of a novel class of mono‐lacunary Dawson polyoxometalate‐(POM‐)based, water‐soluble organometallic complexes, which are expected to be effective homogeneous oxidation catalyst precursors in water, is described. The organometallic complexes K8[{(C6H6)Ru(H2O)}(α2‐P2W17O61)]·12H2O (1) and K8[{(p‐cymene)Ru(H2O)}(α2‐P2W17O61)]·16H2O (2) were successfully prepared by direct reactions of the mono‐lacunary Dawson POM K10[α2‐P2W17O61]·19H2O with the organometallic precursors [(C6H6)RuCl2]2 and [(p‐cymene)RuCl2]2, respectively, in aqueous media and characterized by complete elemental analysis, thermogravimetric and differential thermal analyses (TG/DTA), and FT‐IR and solution (1H, 13C, 31P, and 183W) NMR spectroscopy. The molecular structure of [{(C6H6)Ru(H2O)}(α2‐P2W17O61)]8– (1a), in which the binding of the cationic organometallic group {(C6H6)Ru(H2O)}2+ occurs through two oxygen atoms of the four available oxygen atoms in the mono‐lacunary site of the POM, resulting in overall C1 symmetry, was successfully determined by single‐crystal X‐ray analysis. Interestingly, the hydrophilicity of the organometallic precursors is greatly enhanced by binding to a mono‐lacunary Dawson POM with higher hydrophilicity. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Synthesis of Monodisperse CdS Nanospheres in an Inverse Microemulsion System Formed with a Dendritic Polyether Copolymer
Authors: Wang Fang , Xu Guiying , Zhang Zhiqing , Xin Xia 
Published: November 2005

AbstractNanosized CdS spheres with diameters of about 25, 40, and 50 nm have been synthesized in three inverse microemulsions formed with a dendritic amphiphilic copolymer (H2O/SD31/n‐butanol/n‐heptane) through the reaction of cadmium chloride (CdCl2) with the S2– ions that were slowly released from thioacetamide (TAA). X‐ray powder diffraction (XRD), transmission electron microscopy (TEM), and UV/Vis absorption and photoluminescence (PL) spectroscopy were used to characterize the CdS nanospheres obtained. TEM and XRD studies showed that monodisperse CdS nanospheres with the zinc blende structure were produced, and the size of the CdS spheres increased with increasing water‐core size because of the increasing [water]/[dendrimer] mass ratio (ω). The blue‐shift of the maxima in the UV/Vis absorption and PL spectra indicated that the CdS spheres consisted of primary CdS nanocrystals showing a quantum confinement effect. The viscosities of the three microemulsions were also determined by rheological measurements. The viscosity of the inverse microemulsion system decreased as ω increased. The water core of the inverse microemulsion provided a soft template for the precipitation of CdS spheres.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Copper Complexes with (2,7‐Di‐tert‐butylfluoren‐9‐ylidene)methanedithiolate: Oxidatively Promoted Dithioate Condensation
Authors: Vicente José , González‐Herrero Pablo , García‐Sánchez Yolanda , Jones Peter G. , Bautista Delia 
Published: November 2005

AbstractThe reaction of [Cu(NCMe)4]PF6 with piperidinium 2,7‐di‐tert‐butyl‐9H‐fluorene‐9‐carbodithioate (pipH)[S2C(tBu‐Hfy)] (1; tBu‐Hfy = 2,7‐di‐tert‐butylfluoren‐9‐yl), affords [Cun{S2C(tBu‐Hfy)}n] (2), which reacts with various P ligands to give [Cu{S2C(tBu‐Hfy)}L2] [L = PPh3 (3a), PCy3 (3b), PiPr3 (3d); L2 = 1,1′‐bis(diphenylphosphanyl)ferrocene (dppf, 3c), bis(diphenylphosphanyl)methane (dppm, 3e)]. Compounds 3a–c react with atmospheric oxygen and moisture in the presence of NEt3 to give the dinuclear complexes [Cu2{[SC=(tBu‐fy)]2S}L2] [tBu‐fy = 2,7‐di‐tert‐butylfluoren‐9‐ylidene; L = PPh3 (4a), PCy3 (4b); L2 = dppf (4c)], which contain a new dithiolato ligand formally resulting from the condensation of two dithioato ligands with loss of a sulfide ion and two protons. Neutral CuI dithiolate complexes of the type [Cu4{S2C=(tBu‐fy)}2L4] [S2C=(tBu‐fy) = [2,7‐di‐tert‐butylfluoren‐9‐ylidene)methanedithiolate; L = PPh3 (5a), P(C6H4OMe‐p)3 (5b), PiPr3 (5d) or L2 = dppf (5c)] were obtained by treating 1 with [Cu(NCMe)4]PF6, the corresponding phosphane, and piperidine in a 1:2:2:1 molar ratio. The reaction of 1 with Cu(ClO4)2·6H2O and (Pr4N)OH in a 2:1:2 molar ratio gives the CuII complex (Pr4N)2[Cu{S2C=(tBu‐fy)}2] [(Pr4N)26], which readily oxidizes to the CuIII complex Pr4N[Cu{S2C=(tBu‐fy)}2] (Pr4N7) in the presence of atmospheric oxygen and moisture. The salt PPN7 [PPN+ =(Ph3P)2N+] was obtained from 1, CuCl2·2H2O, PPNCl, and piperidine in a 2:1:1:2 molar ratio under aerobic conditions. The crystal structures of 3a, 3c·CH2Cl2, 4a·4Me2CO, and 4c·CH2Cl2 have been determined by X‐ray diffraction studies. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Variable‐Valent Rhenium Chemistry of Conjugated Nitrogenous Ligands: Structure and Reactivity
Authors: Chakravorty Animesh 
Published: November 2005

AbstractThe valence states of particular concern in this review are VI–I and the ligand types are diimine, azoimine, imineamide and azooximeall bidentate and N,N‐coordinating. Metal reduction potentials and stability of oxidation states are subject to control via variation of the nature and extent of N,N‐chelation and coligation. Back‐bonding plays a major role in determining stability and isomer specificity, particularly in the valence domain III–I. Three types of mediated oxygen atom transfer processes have been scrutinized and modeled: from ReVO to tertiary phosphanes and variable‐spacer diphosphanes, from water to diimine and from oxime to metal/coligand. Other reactivity topics include isomerizations associated with ligand substitution, stable azo anion radical generation and azo cleavage. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
A New Coordination Polymer Architecture with (10,3)‐a Network Containing Chiral Hydrophilic 3‐D Channels
Authors: Zharkouskaya Aksana , Buchholz Axel , Plass Winfried 
Published: November 2005

AbstractThe triaminoguanidine‐based Schiff‐base ligand H5LOH reacts with copper(II) ions to afford a three‐dimensional coordination polymer with (10,3)‐a topology which is solely assembled by a single trigonal molecular building block {Cu3LOH}+. The unusual bridging mode of the phenolate oxygen atoms between the trigonal building blocks leads to a dihedral angle between the interlinked {Cu3LOH}+ units of 71°. The (10,3)‐a topology of the singular network results in a rather large void space of about 56 % that is established by interpenetrated chiral channels with a diameter limited by pseudo‐tetrahedral cavities defined by non‐coordinating phenolate hydroxy groups of the ligand. Additional information to establish the composition is derived from elemental analysis and TGA measurements. For the coordination polymer an overall antiferromagnetic behavior is observed. The spin‐frustrated trinuclear building blocks {Cu3LOH}+ are antiferromagnetically coupled via the bis(phenoxide)‐bridged dinuclear copper(II) moieties for which a dihedral angle of 132° is observed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Dinuclear Lanthanide Schiff‐Base Complexes Forming a Rectangular Columnar Mesophase
Authors: Binnemans Koen , Lodewyckx Katleen , Cardinaels Thomas , Parac‐Vogt Tatjana N. , Bourgogne Cyril , Guillon Daniel , Donnio Bertrand 
Published: November 2005

AbstractThe Schiff base LH3 obtained by condensation of 3‐formyl‐4‐hydroxyphenyl‐3,4,5‐tris(tetradecyloxy)benzoate with 1,3‐diamino‐2‐propanol reacts with lanthanide(III) acetate salts to form dinuclear complexes of the type Ln2L2 with the trivalent ions from the first half of the lanthanide series (Ln = Nd, Sm, Gd). These stable and neutral metallomesogens exhibit a rectangular columnar mesophase over a broad temperature range. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
The Hexakis(thiocyanato)ferrate(III) Ion: a Coordination Chemistry Classic Reveals an Interesting Geometry Pattern for the Thiocyanate Ligands
Authors: Addison Anthony W. , Butcher Raymond J. , Homonnay Zoltán , Pavlishchuk Vitaly V. , Prushan Michael J. , Thompson Laurence K. 
Published: November 2005

AbstractWe are grateful to Professor Ulrich Müller, of Philipps‐Universität Marburg, for drawing the attention of ourselves and the referees to a prior structure report for (NMe4)3[Fe(NCS)6].1 The 1977 and 20052 reports differ only in the choice of unit cell origin. The conclusions from the structure–spectra relationships discussed in the 2005 paper remain the same.
Cycloadditions to Alkenyl[2.2]paracyclophanes
Authors: Aly Ashraf A. , Ehrhardt Sonja , Hopf Henning , Dix Ina , Jones Peter G. 
Published: November 2005

AbstractCycloadditions between the 4‐alkenyl[2.2]paracyclophanes 7, 16–21 and the dienophiles 10a–h have been studied. Whereas 10a, b, d, and g prefer Diels–Alder addition involving the olefinic double bond and one double bond of a cyclophane benzene ring, 10c, e, f, and h undergo other cycloadditions such as ene reaction (10c), [2+2] cycloaddition to the olefinic double bond (10e) and heterodiene addition to the vinyl substituent (10f, h). Several of the isolated cycloadducts (e.g. 24–26, 52) are valuable substrates for the preparation of annelated cyclophanes. The mechanisms of several of these cycloadditions are discussed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Ketene Chemistry after 100 Years: Ready for a New Century
Authors: Tidwell Thomas T. 
Published: November 2005

AbstractThe existence of ketenes was established 100 years ago, and in recent years the pace of discovery in the study of these reactive intermediates has accelerated — extremely unstable ketenes such as difluoroketene have been directly observed for the first time, while a variety of bisketenes stabilized by silyl substituents have been isolated as long‐lived compounds at room temperature. New methods for generating ketenes for applications in synthesis have been devised, and these have been applied in the preparation of many valuable targets. Asymmetric synthesis by nucleophilic additions and by [2+2] cycloadditions to ketenes to form β‐lactams and β‐lactones has been achieved with high yields and high stereoselectivities. The free‐radical chemistry of ketenes is receiving increasing levels of attention, and new rearrangement reactions of ketenes have been developed. These advances create new opportunities to utilize the unique structures and high reactivity of ketenes for even greater progress in the future. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
One‐Pot Synthesis of Orthogonally Protected Enantiopure S‐(Aminoalkyl)cysteine Derivatives
Authors: Bolognese Adele , Fierro Olga , Guarino Daniela , Longobardo Luigi , Caputo Romualdo 
Published: November 2005

AbstractThe general synthesis of a new class of non‐natural diamino acids, 2‐amino‐3‐[(2′‐aminoalkyl)thio]propanoic acids or S‐(aminoalkyl)cysteines, is reported. Under the conditions devised, enantiopure N‐Boc‐protected β‐iodoamines, readily generated from proteinogenic α‐amino acids, are treated with L‐cysteine ethyl ester hydrochloride, using Cs2CO3 as a base. The S‐alkylation products, obtained in high yields (96–98 %) and without any detectable traces of accompanying byproducts, are hydrolysed to yield the free carboxyl group. An orthogonal protection is then introduced on the free amino group by treatment with Fmoc‐OSu under standard conditions. The inclusion of one of these orthogonally protected diamino acids in a solid‐phase growing pentapeptide is also reported. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Syntheses of O6‐Alkyl‐ and Arylguanine Derivatives: Nucleobase Adducts Derived from Styrene 7,8‐ and 3,4‐Oxides
Authors: Novák Jan , Hasník Zbyněk , Linhart Igor 
Published: November 2005

AbstractA series of O6‐alkyl and ‐arylguanine derivatives that may be formed in vivo after exposure to styrene has been prepared by reaction of 6‐(4‐aza‐1‐azoniabicyclo[2.2.2]octyl)‐purine with alkoxides and aryloxides, respectively. Themonoprotected diols 2‐allyloxy‐ or 2‐benzyloxy‐1‐phenylethanol and 2‐allyloxy‐ or 2‐benzyloxy‐2‐phenylethanol were used as synthetic equivalents of styrene 7,8‐oxide. 4‐Vinylphenol, 2‐(4‐hydroxyphenyl)ethanol and 4‐hydroxyphenylacetic acid were used as synthetic equivalents of arene oxide metabolites of styrene, i. e., styrene 3,4‐oxide, 4‐(2‐hydroxyethyl)benzene 1,2‐oxide and 4‐carboxymethylbenzene 1,2‐oxide, respectively. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Ion‐Pairing Effects in the Self‐Assembly of a Fluorescent Pseudorotaxane
Authors: Clemente‐León Miguel , Pasquini Chiara , Hebbe‐Viton Virginie , Lacour Jerome , Dalla Cort Antonella , Credi Alberto 
Published: November 2005

AbstractHerein we report on the self‐assembly, in a low polarity solvent, of a pseudorotaxane species comprising binaphthyl‐26‐crown‐8 (BN26C8) as the macrocyclic host and anthracenyl‐benzylammonium as the threadlike positively charged guest (ABH+). Absorption and luminescence data reveal a very efficient energy transfer process occurring from the binaphthyl to the anthracene singlet excited states. The self‐assembly is highly dependent on the nature of the counteranion confirming the crucial role played by it in the competition between the self‐assembly process and the formation of ion pairs (ABH+X–). This behavior can be readily evidenced in dilute solutions from the analysis of the luminescence properties of the system. The complexation of chloride, sulfate and hexafluorophosphate salts of ABH+ by racemic BN26C8 as well as the complexation of ABH+ salts of the chiral anion tris[tetrachlorobenzenediolato]phosphate(V) (TRISPHAT–) by (+)BN26C8 are described. The efficiency in complexation follows the trend PF6– > TRISPHAT– > Cl–, SO42–. The use of the chiral anion TRISPHAT allowed us to investigate the possibility of inducing stereoselective control on the formation of the interpenetrating assembly. Preliminary 1H NMR spectroscopic evidence supports the fact that the chiral anion is paired to the supramolecular complex and that its configuration influences the recognition process. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
NMR Enantiodiscrimination of Polar and Apolar Substrates by Multifunctional Cyclodextrins
Authors: Uccello‐Barretta Gloria , Balzano Federica , Sicoli Giuseppe , Scarselli Alessandro , Salvadori Piero 
Published: November 2005

AbstractMixed methylated/carbamoylated cyclodextrins constitute a new class of chiral complexing agents for NMR spectroscopy, which are able to induce anisochrony of enantiomeric mixtures of apolar trisubstituted allenes and polar derivatized compounds most of which are endowed with a π‐acidic 3,5‐dinitrophenyl ring. The differing contribution to enantiorecognition phenomena of the nature and location of the functional groups on the two cyclodextrin rims was shown. Some interesting aspects of the complexation phenomena, which are the basis of chiral recognition, have been underlined by NMR spectroscopic investigations.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Substituent Effects on the Gas‐Phase Basicity of Formamidine Ureas
Authors: Díaz David D. , Finn M. G. , Mishima Masaaki 
Published: November 2005

AbstractThe gas‐phase basicities (GBs) for a representative set of six formamidine ureas with variations in the imino substituent [RN=CH–N(Me)C(O)NMe2] were determined in proton‐transfer equilibria by ion cyclotron resonance (ICR) mass spectrometry and further explored with calculations at the B3LYP/6‐31+G* level. The GB values, ranging from 218.6 to 230.9 kcal mol–1, were also compared with those previously reported for N1,N1‐dimethyl‐N2‐substituted formamidines. For all compounds investigated, protonation occurs preferentially at the imino nitrogen. In the cases of R = n‐C7H15, Ph(CH2)3 and Ph, no stable O‐protonated structures exist which can transfer proton to the N atom without a significant barrier. Relative GBs were linearly correlated to the inductive effect of the imine nitrogen substituents. The calculated structures are also given, and the calculated basicities are in good agreement with the observed values. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Synthesis and Electronic Properties of 3‐Acceptor‐Substituted and 3,7‐Bisacceptor‐Substituted Phenothiazines
Authors: Sailer Markus , Nonnenmacher Michael , Oeser Thomas , Müller Thomas J. J. 
Published: November 2005

Abstract3‐Acceptor‐substituted and 3,7‐bisacceptor‐substituted phenothiazines can be synthesized in moderate to excellent yields through Suzuki cross‐coupling reactions between phenothiazin‐3‐yl pinacolyl boronates or phenothiazin‐3,7‐diyl bis(pinacolyl boronates) and electron‐deficient (hetero)aryl halides. The electronic properties of (hetero)aryl‐substitutedN‐methyl phenothiazines (UV/Vis absorption, fluorescence, redox potentials) can be correlated with the computed energies of the frontier molecular orbitals. Nitro‐substituted derivatives reveal electronically amphoteric behavior, displaying both reversible oxidations and reversible reductions. X‐ray structure analysis of the phenothiazinylp‐(2,5‐dinitro)phenylene‐bridged dyad13revealed donor–acceptor interactions between the molecules. Pyridyl and pyrimidyl derivatives fluoresce with quantum yields (Φf) of up to 49 % and can be regarded as redox‐active fluorophores. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Preparation of Conformationally Constrained α2‐Antagonists: The Bicyclo[3.2.0]heptane Approach
Authors: Bonnaud Bernard , Mariet Natacha , Vacher Bernard 
Published: November 2005

AbstractThe aim of this research was to discover α2‐receptor antagonist subtypes that are more selective than known compounds. We focused on rigid molecules possessing a benzo‐fused bicyclo[3.2.0]heptane skeleton. The synthetic route used relied upon the intramolecular [2+2] cycloaddition of styrylketene precursors. The cycloaddition was remarkably efficient and delivered multigram quantities of the cycloadduct 2. Studies of the removal of the ketone group in 2 revealed a facile opening of the four‐membered ring. Upon thermal elimination of TCI‐13‐endo (TCI = thiocarbonylimidazole) and TCI‐13‐exo, different products were obtaineddepending on the stereochemistry of the OH function of the precursor. Distinct mechanisms were proposed to account for the divergent outcomes observed. Double bond reductions from either methylcyclobutene or methylenecyclobutane isomers were thoroughly investigated in order to optimize the stereocontrol at the C‐1 position. Hydrogenation of the internal π‐bond produced an endo‐1‐methylcyclobutane derivative with high diastereoselectivity, whereas the exo‐1‐methyl isomer was best isolated by chromatographic separation of the acid 37. Finally, the prototypic imidazolidines 1, unsubstituted and bearing a methyl group at C‐1, were synthesized for biological evaluation.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Synthesis and Photophysical Studies of New Porphyrin–Phthalocyanine Dyads with Hindered Rotation
Authors: Tomé João P. C. , Pereira Ana M. V. M. , Alonso Cristina M. A. , Neves Maria G. P. M. S. , Tomé Augusto C. , Silva Artur M. S. , Cavaleiro José A. S. , Martínez‐Díaz M. Victoria , Torres Tomás , Rahman G. M. Aminur , Ramey Jeff , Guldi Dirk M. 
Published: November 2005

AbstractA series of novel porphyrin–phthalocyanine (Por‐Pc) dyads1–3have been synthesized by using standard methodologies for unsymmetrically substituted phthalocyanine preparation. These two chromophoric units have been directly linked for the first time, that is, without any spacer, through the β‐pyrrolic position of ameso‐tetraphenylporphyrin, thus allowing a close proximity of the two units in a rigid arrangement. For this, a novel porphyrin–phthalonitrile precursor4had to be prepared. The UV/Vis spectra indicate that the basic electronic characteristics of both individual units (i. e., porphyrin and phthalocyanine) are retained in the hybrid Por‐Pc molecules. The short Por‐Pc separation in dyads1–3leads to strong excitonic coupling and ultrafast energy transfer (ca. 1012s–1), as determined by femtosecond transient absorption measurements, from the highly energetic1*(ZnPor) unit to the1*(ZnPc), which evolves to populate the long‐lived3*(ZnPc) by intersystem crossing. Interestingly, the energy transfer seems to occur more efficiently in dyads2and3, which have smaller HOMO–LUMO energy gaps. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)