Syntheses, structures, and electrochemical properties of platinum(II) complexes containing di-tert-butylbipyridine and crown ether annelated dithiolate ligands

A series of new platinum(II) complexes containing both 4,4'-di-tert-butyl-2,2'-bipyridine (dbbpy) and the extended tetrathiafulvalenedithiolate ligands have been prepared and characterized. These complexes include [Pt(dbbpy)(C8H4S8)] (1; C8H4S82- = 2-{(4,5-ethylenedithio)-1,3-dithiol-2-ylidene}-1,3-dithiol-4,5-dithiolate), [Pt(dbbpy)(ptdt)] (2; ptdt = 2-{(4,5-cyclopentodithio)-1,3-dithiol-2-ylidene}-1,3-dithiol-4,5-dithiolate), [Pt(dbbpy)(mtdt)] (3; mtdt = 2-{(4,5-methylethylenedithio)-1,3-dithiol-2-ylidene}-1,3-dithiol-4,5-dithiolate), [Pt(dbbpy)(btdt)] (4; btdt = benzotetrathiafulvalenedithiolate), [Pt(dbbpy)(C8H6S8)] (5; C8H6S82- = 2-{4,5-bis(methylthio)-1,3-dithiol-2-ylidene}-1,3-dithiol-4,5-dithiolate), [Pt(dbbpy)(3O-C6S8)] (6; 3O-C6S82- = 2-{4,5-dithia-(3',6',9'-trioxaundecyl)-1,3-dithiol-2-ylidene}-1,3-dithiol-4,5-dithiolate), and [Pt(dbbpy)(4O-C6S8)] (7; 4O-C6S82- = 2-{4,5-dithia-(3',6',9',12'-tetraoxatetradecyl)-1,3-dithiol-2-ylidene}-1,3-dithiol-4,5-dithiolate). The crystal structures of a new ligand precursor (2-[4,5-dithia-(3',6',9',12'-tetraoxatetradecyl)-1,3-dithiol-2-ylidene]-4,5-bis(2-cyanoethylsulfanyl)-1,3-dithiole, IIIc) and complexes 5-7 have been determined by X-ray crystallography. Complexes 1-7 show intense electronic absorption bands in the UV-vis region due to the intramolecular mixed metal/ligand-to-ligand charge-transfer transition, and they display significant solvatochromic behavior. Redox properties of these compounds have been investigated by cyclic voltammetry, and complex 7 shows a significant response for Na+ ions with a large positive shift of ca. 45 mV.     

Synthesis of bis-fused tetrathiafulvalene with mono- and dicarboxylic acids

Bis-fused tetrathiafulvalenes with mono- and dicarboxylic acids, 2-{5-(1,3-dithiol-2-ylidene)-[1,3]dithiolo[4,5-d][1,3]dithiol-2-ylidene}-1,3-dithiole-4-carboxylic acid (1) and 2-{5-(1,3-dithiol-2-ylidene)-[1,3]dithiolo[4,5-d][1,3]dithiol-2-ylidene}-1,3-dithiole-4,5-dicarboxylic acid (2) have been synthesized. The electronic structure of 1 and 2 was examined from their optical absorption spectra and using density-functional calculations.     

A (pi-extended tetrathiafulvalene)-fluorene conjugate. Unusual electrochemistry and charge transfer properties: the first observation of a covalent D(2+)-sigma-A(.-) redox state(1)

The synthesis of novel electrochemically amphoteric TTFAQ-sigma-A compounds (TTFAQ = 9,10-bis(1,3-dithiol-2-ylidene)-9,10-dihydroanthracene, sigma = saturated spacer, A = polynitrofluorene acceptor) is reported. Their solution redox behavior is characterized by three single-electron reduction and one two-electron oxidation waves. Electrochemical quasireversibility of the TTFAQ(2+) state and a low E(ox) - E(red) gap ( approximately 0.25 V) for 3-(9-dicyanomethylene-4,5,7-trinitrofluorene-2-sulfonyl)-propionic acid 2-[10-(4,5-dimethyl-[1,3]dithiol-2-ylidene)-9,10-dihydroanthracen-9-ylidene]-5-methyl-[1,3]dithiol-4-ylmethyl ester (10) has enabled the electrochemical generation of the hitherto unknown transient D(2+)-sigma-A(.-) state as observed in cyclic voltammetry and time-resolved spectroelectrochemistry. The ground state of compound 10 was shown to be ionic in the solid but is essentially neutral in solution (according to electron paramagnetic resonance). The X-ray structure of an intermolecular 1:2 complex between 2-[2,7-bis(2-hydroxyethoxy)-9,10-bis(4,5-dimethyl-[1,3]dithiol-2-ylidene)-9,10-dihydroanthracene and 2,5,7-trinitro-4-bromo-9-dicyanomethylenefluorene, 14.(17)(2), reveals, for the first time, full electron transfer in a fluorene charge-transfer complex.     

冠醚环化二硫烯双核Au(I)配合物的合成、结构及电化学性质

合成了含有冠醚环化二硫烯的双核Au(I)配合物[(30-C2S4)Au2(PPh3):](1),[(40-C2S4)Au2·(PPh3)2](2),[(30一C6-S8)Au2(Pph3)2](3)和[(40-C6-S8)Au2(PPh3)2](4)以及富硫配合物[(btdt)Au2·(PPh3)2](5).通过x射线...     

New strategies and building blocks for functionalised 9,10-bis(1,3-dithiol-2-ylidene)-9,10-dihydroanthracene derivatives,including pyrrolo-annelated derivatives and pi-extended systems with intramolecular charge-transfer

A range of new functionalised 9,10-bis(1,3-dithiol-2-ylidene)-9,10-dihydroanthracene (TTFAQ) derivatives have been synthesised from the key di(halomethyl) building blocks, 10-[4,5-bis(bromomethyl)-1,3-dithiol-2-ylidene]-anthracene-9(10H)-one 10, 10-[4,5-bis(chloromethyl)-1,3-dithiol-2-ylidene]anthracene-9(10H)-one 11 and 9-[4,5-bis(chloromethyl)-1,3-dithiol-2-ylidene]-10-[4,5-bis(hexylsulfanyl)- 1,3-dithiol-2-ylidene]-9,10-dihydroanthracene 18. A Diels-Alder strategy comprising trapping of the transient exocyclic diene 19, which is derived from 18, with 1,4-naphthoquinone leads to the aromatised TTFAQ anthraquinone system 21. Horner-Wadsworth-Emmons olefination of 21 with the anion generated from reagent 22 gave the fused bis(TTFAQ) structure 23. Pyrrolo-annelated derivatives 30-34 have been obtained in a sequence of reactions from compound 10. Mono-formylation of the pyrrole ring of 32 and 33 under Vilsmeier conditions gave 35 and 36 which upon reaction with 2,4,5,7-tetranitrofluorene gave the donor-pi-acceptor diads 38 and 39. Cyclic voltammetry (CV) in solution for all the TTFAQ derivatives shows the typical quasi-reversible two-electron oxidation wave of the TTFAQ core at potentials which vary slightly depending on the substituents. For example, the value of Eox is raised by the electron withdrawing anthraquinone and tetranitrofluorene units of 21 and 38, respectively. The CV of the conjugated TTFAQ dimer 23 showed two, two-electron oxidation waves corresponding to the sequential formation of 23(2+) and 23(4+) (delta Eox = 130 mV) providing evidence for a significant intramolecular electronic interaction, i.e. the dication 23(2+) acts as a conjugated donor-pi-acceptor diad, thereby raising the oxidation potential of its partner TTFAQ unit. Spectroelectrochemical studies on 23 support this explanation. A strong intramolecular charge transfer band at lambda max 538 nm is seen in the UV-Vis spectra of the TTFAQ-pi-tetranitrofluorene diads 38 and 39. The X-ray crystal structures are reported for compounds 30, 33 and 34. The pyrrolo-TTFAQ moiety adopts a saddle-shape with the central ring of the dihydroanthracene moiety folded along the C(9) ... C(10) vector in each case. Significant intermolecular interactions are observed in the structures.     

Unique Thermal Structural Phase Transitions Exhibited by Unsymmetrical Organometallic Gold(III)-Dithiolene Complexes with Pentylthio and Hexylthio Groups

Unsymmetrical gold(III)-dithiolene complexes are potential candidates for molecular materials that exhibit thermal structural phase transitions. In this study, unsymmetrical ppy-gold(III) (ppy⁻=C-deprotonated-2-phenylpyridine(−)) complexes [AuC5] and [AuC6] coordinated by dithiolene ligands containing tetrathiafulvalene (TTF) skeletons with pentylthio (2-{bis(pentylthio)-1,3-dithiol-2-ylidene}-1,3-dithiol-4,5-dithiolate(2−)) and hexylthio groups (2-{bis(hexylthio)-1,3-dithiol-2-ylidene}-1,3-dithiol-4,5-dithiolate(2−)) were synthesized. Both complexes exhibited a large absorption band at approximately 508 nm, owing to intramolecular ligand-to-ligand charge transfer. One-dimensional columnar structures with head-to-tail molecular arrangements around the metal ions were constructed in the crystals. The flexible alkylthio groups were intercalated into crystalline spaces between dithiolene ligands in the columns. [AuC5] exhibits a simple phase transition at 198 °C between crystalline and isotropic phases irreversibly. The crystalline phase of [AuC6] observed at 25 °C melted at 148 °C. Another crystalline phase grew above 148 °C with a very slow crystallization rate from the liquid phase and was completely transformed into an isotropic phase at 200 °C.     

含吡啶基四硫富瓦烯衍生物的合成、 结构和电化学性质

在乙酰乙酸乙酯和氧化亚铜共同催化下, 二-(1,3-二硫环戊烯-2-硫酮-4,5-二硫)合锌酸四乙基铵盐分别与2-碘吡啶(1a)、 3-碘吡啶(1b)和4-碘吡啶(1c)反应, 制得硫酮化合物2,3-二(2-吡啶硫基)-1,3-二硫环戊烯-2-硫酮(2a)、 2,3-二(3-吡啶硫基)-1,3-二硫环戊烯-2-硫酮(2b)和2,3-二(4-吡啶硫基)-1,3-二硫环戊烯-2-硫酮(2c). 在醋酸汞催化下, 硫酮化合物2a, 2b和2c分别被氧化为2,3-二(2-吡啶硫基)-1,3-二硫环戊烯-2-酮(3a)、 2,3-二(3-吡啶硫基)-1,3-二硫环戊烯-2-酮(3b)和2,3-二(4-吡啶硫基)-1,3-二硫环戊烯-2-酮(3c). 以亚磷酸三乙酯为偶联剂, 氧酮化合物3a, 3b和3c分别发生自偶联反应生成2,3,6,7-四(2-吡啶硫基)四硫富瓦烯(4a)、 2,3,6,7-四(3-吡啶硫基)四硫富瓦烯(4b)和2,3,6,7-四(4-吡啶硫基)四硫富瓦烯(4c). 采用核磁共振波谱(NMR)、 傅里叶变换红外光谱(FTIR)和质谱(MS)分析了所合成化合物的结构和组成, 通过X射线衍射分析确认了吡啶基四硫富瓦烯衍生物4b和4c的晶体结构. 循环伏安法研究结果表明, 化合物4a, 4b和4c呈现准可逆的两电子转移过程, 结合量子化学计算, 分析了不同位置取代的吡啶基对四硫富瓦烯电化学电势的影响.     

Dinuclear rhenium(I) carbonyl complexes based on π-conjugated polypyridyl ligands with tetrathiafulvalenes: Syntheses, crystal structures, properties and DFT calculations

A series of tetrathiafulvalene-substituted 2,3-di(2-pyridyl)quinoxaline (dpq) ligands, 2-(4,5-bis(methylthio)-1,3-dithiol-2-ylidene)-6,7-di(pyridin-2-yl)- [1,3]dithiolo[4,5-g]quinoxaline (L₁), dimethyl-2-(6,7-di(pyridin-2-yl)-[1,3]dithiolo[4,5-g]quinoxalin-2-ylidene)-1,3-dithiole-4,5-dicarboxylate (L₂), and 2-(5,6-dihydro-[1,3]dithiolo[4,5-b] [1,4]dithiin-2-ylidene)-6,7-di(pyridin-2-yl)-[1,3]dithiolo[4,5-g]quinoxaline (L₃), have been prepared. Reactions of these ligands with Re(CO)₅Cl afford the corresponding dinuclear rhenium(I) carbonyl complexes, Re₂(L)(CO)₆Cl₂ (L = L₁, 5a; L = L₂, 5b; L = L₃, 5c). All new compounds are fully characterized by ¹H NMR, IR and mass spectroscopies. The crystal structures of 5a and 5b have been studied. Optimized conformations and molecular orbital diagrams of 5a−5c have been calculated with density functional theory (DFT). The spin-allowed singlet−singlet electronic transitions of all complexes have been calculated with time-dependent DFT (TDDFT), and the UV-Vis−NIR spectra are discussed based on the theoretical calculations.     

新型不对称双席夫碱化合物的合成及其晶体结构

采用“一锅法”,小分子NH₃和水杨醛分别与2-氨甲基吡啶和4-氨甲基吡啶经缩合反应合成了两种新型的不对称双席夫碱化合物--2-{1,2-二［(E)-2-羟基苯亚甲氨基］-2-(2-吡啶基)乙基}苯酚(2a)和2-{1,2-二［(E)-2-羟基苯亚甲氨基］-2-(4-吡啶基)乙基}苯酚(2b),其结构经¹H NMR, ¹³C NMR, IR和X-射线单晶衍射(2b)表征。2b(CCDC： 1 423 247)属单斜晶系,P2(1)/n空间群,晶胞参数a=10.764(3) , b=9.725(2) , c=21.934(5) , β=93.291(9) °, V=2 292.2(9) ³, Dc=1.268 mg·cm^-3, Z=4, F(000)=920, μ=0.084 mm^-1。     

具有螺旋结构的金属镍有机-无机配位聚合物的合成及表征

在水热体系中合成了3个中心金属为镍离子, 以六配位扭曲八面体构型形成的具有螺旋结构的配位聚合物{[Ni₂L₂(bib)₂·2H₂O]·5H₂O}_n(1), [Ni₂L₂(bpy)]_n(2)和{[Ni₂L₂(bibpip)₂·2H₂O]·6H₂O}_n(3)[H₂L=4,4'-三苯胺二甲酸; bib=1,3-二(咪唑基)苯; bpy=4,4-联吡啶; bibpip=1,4-二(4-咪唑苄基)哌嗪]. 通过单晶及粉末X射线衍射、 红外光谱、 元素分析和热重分析对这3种化合物进行了表征. 结果表明, 化合物1属于单斜晶系, C2/c空间群, 其骨架为具有{4²·6⁵·8}拓扑结构的二维层结构; 化合物2属于斜方晶系, Fdd2空间群, 其骨架为具有{4⁸·5⁴·6³}拓扑结构的三维超分子网络; 化合物3属于三斜晶系, P\begin{array}{c}\bar{1}\end{array}空间群, 为1个五重穿插的三维超分子网络, 其骨架具有{4⁴·6²}拓扑结构.     

(4-甲基-1,3-二噻烷-2-亚甲基)-1,7-二芳基-1,6-二烯-3,5-二酮的合成

从2,4-戊二酮和1,2,3-三溴丙烷出发合成了一类新的α-羰基二硫缩烯酮类化合物,并以其为底物合成了(4-甲基-1,3-二噻烷-2-亚甲基)-1,7-二芳基-1,6-二烯-3,5-二酮类化合物,通过IR和1H NMR方法对其进行了表征.     

Synthesis and Electrochemical Behavior of Electroactive Bistetrathiafulvalene-attached Thiacalix[4]arene Assemblies

Tetrabromoalkylthiacalix[4]arenes(1a and 1b) reacted with excess bis(tetraethylammonium)-bis(1,3- dithiole-2-thione-4,5-dithiol)zincate(2) to give thiacalix[4]arene-thiones(3a and 3b) in the presence of Na₂S. Two novel bistetrathiafulvalene-attached thiacalix[4]arene assemblies(5a and 5b) formed via triethyl phosphite-mediated cross-coupling of thiacalix[4]arene-thiones(3a and 3b) and 4,5-biscyanoethylthio-1,3-dithiole-2-one(4). All the four new compounds were characterized by ¹H NMR, ¹³C NMR, IR, MS spectra and elemental analysis. Meanwhile, the structures of thiacalix[4]arene-thiones(3a and 3b) were identified by X-ray analysis. In addition, the cyclic voltammograms of the resulting thiacalix[4]arenes containing electroactive TTF units(5a and 5b) were provided.     

Syntheses,crystal structures and properties of two novel imino-π-extended TTF derivatives

Two novel conjugated imino-π-extended tetrathiafulvalenes with p-iminobenzene, N,N′-bis(4,5-bis(methylthio)-1,3-dithiol-2-ylidene)benzene-1,4-diamine (1) and N,N′-bis(4,5-bis(ethylenedithio)-1,3-dithiolo-2-ylidene)benzene-1,4-diamine (2), have been synthesized and characterized by NMR, IR, MS and X-ray single-crystal diffraction. Both the two targets adopt chair-like conformation, and the central rings of p-iminobenzene moieties of the two molecules are severely twisted from the planarity of two dithiole rings, respectively. The UV–vis spectra of 1 and 2 show the lowest-energy absorption bands caused by the HOMO–LUMO one-electron promotion. Cyclic voltammetry (CV) measurements show only one, two-electron irreversible oxidation picks. These experimentally estimated energy levels of the frontier orbital of 1 and 2 (E_HOMO 1: = ?5.45, 2: ?5.47 eV) are in good agreement with those obtained from DFT calculations (E_HOMO 1: = ?5.5, 2: = ?5.3 eV). The high HOMO–LUMO gaps of 1 (4.05 eV) and 2 (4.00 eV) indicate high kinetic stability of the title compounds.     

Electronic structures and charge transport properties of the organic semiconductor bis[1,2,5]thiadiazolo-p-quinobis(1,3-dithiole), BTQBT, and its derivatives

We analyze the correlation between crystal and film structures and charge transport of an important organic semiconductor, bis[1,2,5]thiadiazolo-p-quinobis(1,3-dithiole) (BTQBT), and its derivatives 4,8-bis(1,3-dithiol-2-ylidene)-4H,8H-[1,2, 5]selenadiazolo[3,4-f]-2,1,3-benzothiadiazole, 4,8-bis(1,3-diselenol-2-ylidene)-4H,8H-benzo[1,2-c:4,5-c']bis[1,2,5]thiadiazole, and tetramethyl-BTQBT. We present first-principles density functional theory (DFT) calculations that agree well with earlier angle-resolved photoelectron spectroscopy (ARPES) experiments on BTQBT films, strongly supporting that the BTQBT films adopt the same layered structure as in the single crystals. Qualitative charge transport properties based on presented DFT results agree with experiments regarding the sign of the charge carriers and the unusually small anisotropy of conductivity. These agreements indicate that accurate electronic structure calculations, when coupled with ARPES, help establish the correlation between intermolecular packing and charge transport, which is one of the central but elusive aspects of organic molecular materials. Predictions are made for derivatives of BTQBT, and calculations agree with available experimental information on the conductivities. Comparisons are made with pentacene, one of the most widely studied organic molecular materials.     

3-(4,5-二苄硫基-1,3-二硫杂环戊烯-2-亚基)萘吡喃酮的合成、性质及量子化学计算

设计合成了一种新的具有D-π-A体系的有机分子:3-(4,5-二苄硫基-1,3-二硫杂环戊烯-2-亚基)萘吡喃酮,通过UV-vis,1H NMR,13C NMR,TOFMS和IR确定了其结构.初步研究了该化合物的电子光谱、荧光光谱和热稳定性.运用Gaussian 03量子化学程序包,采用密度泛函(DFT)B3PW91的方法优化了其基态几何结构,得到的几何参数与实验结果吻合得很好.研究结果表明,体系中存在着分子内的电荷转移,有较好的荧光性质,为寻找新的发光材料具有一定的实际意义.     

The interplay of inverted redox potentials and aromaticity in the oxidized states of new pi-electron donors: 9-(1,3-dithiol-2-ylidene)fluorene and 9-(1,3-dithiol-2-ylidene)thioxanthene derivatives

Derivatives of 9-(1,3-dithiol-2-ylidene)fluorene (9) and 9-(1,3-dithiol-2-ylidene)thioxanthene (10) have been synthesised using Horner-Wadsworth-Emmons reactions of (1,3-dithiol-2-yl)phosphonate reagents with fluorenone and thioxanthen-9-one. X-ray crystallography, solution electrochemistry, optical spectroscopy, spectroelectrochemistry and simultaneous electrochemistry and electron paramagnetic resonance (SEEPR), combined with theoretical calculations performed at the B3P86/6-31G** level, elucidate the interplay of the electronic and structural properties in these molecules. These compounds are strong two-electron donors, and the oxidation potentials depend on the electronic structure of the oxidised state. Two, single-electron oxidations (E(1)ox < E(1)ox) were observed for 9-(1,3-dithiol-2-ylidene)fluorene systems (9). In contrast, derivatives of 9-(1,3-dithiol-2-ylidene)thioxanthene (10) display the unusual phenomenon of inverted potentials (E(1)ox > E(1)ox) resulting in a single, two-electron oxidation process. The latter is due to the aromatic structure of the thioxanthenium cation (formed on the loss of a second electron), which stabilises the dication state (10(2+)) compared with the radical cation. This contrasts with the nonaromatic structure of the fluorenium cation of system 9. The two-electron oxidation wave in the thioxanthene derivatives is split into two separate one-electron waves in the corresponding sulfoxide and sulfone derivatives 27-29 owing to destabilisation of the dication state.     

Solvent effects on the three-photon absorption cross-section of a highly conjugated fluorene derivative

Herein, we report the study of the three-photon absorption cross-section dependence on solvents parameters for a highly conjugated organic dye, 2,2'-(4,4'-(1E,1'E)-2,2'-(9,9-didecyl-9H-fluorene-2,7-diyl) bis(ethene-2,1-diyl)bis(4,1-phenylene))dibenzo[d]thiazole (A-pi-pi-pi-A). The three-photon absorption cross-section was measured for this organic dye in solution in four different solvents with polarity function, Deltaf between 0.162 and 0.247. The experiments show how the solvent's reorientation of the electrons and polarity contribute to the 3PA cross-section. Multiphoton-absorption experiments of A-pi-pi-pi-A in all four different solvents were performed with a tunable OPG pumped by a 25 picosecond Nd-YAG laser.     

High-extinction ruthenium compounds for sunlight harvesting and hole transport

The compounds Ru(bpy) 2(BTL)(PF 6) 2 and Ru(deeb) 2(BTL)(PF 6) 2, where bpy is 2,2'-bipyridine, deeb is 4,4'-(C 2H 5CO 2) 2-bpy, and BTL is 9'-[4,5-bis(cyanoethylthio)]-1,3-dithiol-2-ylidene]-4',5'-diazafluorene, were found to have very high extinction coefficients in the visible region. In an acetonitrile solution, the extinction of Ru(deeb) 2(BTL)(PF 6) 2 was = 44 000 +/- 1000 M (-1) cm (-1) at lambda = 470 nm. Two quasi-reversible oxidation waves, E 1/2 = +0.88 and +1.16 V, and an irreversible reduction, E pr = -1.6 V, were observed versus ferrocene (Fc (+/0)). At -40 degrees C, a state was observed with spectroscopic properties characteristic of a metal-to-ligand charge-transfer excited state, tau = 25 ns. This same compound was found to photoinject electrons into TiO 2 with a quantum yield Phi = 0.3 +/- 0.2 for 532.5 or 417 nm light excitation in a 0.1 M LiClO 4/acetonitrile electrolyte. In regenerative solar cells, a sustained photocurrent was observed with a maximum incident photon-to-current efficiency of 0.4. The photocurrent action and absorptance spectra were in good agreement, consistent with injection from a single excited state.     

Transient excited-state absorption and gain spectroscopy of a two-photon absorbing probe with efficient superfluorescent properties

The synthesis, linear photophysical properties, two-photon absorption (2PA), excited-state transient absorption, and gain spectroscopy of a new fluorene derivative tert-butyl 4,4'-(4,4' (1E,1'E)-2,2'-(9,9-bis(2- (2-ethoxyethoxy)ethyl)-9H-fluorene-2,7-diyl)bis(ethene-2,1-diyl)bis(4,1 phenylene)]dipiperazine-1-carboxylate (1) are reported. The steady-state linear absorption and fluorescence spectra, along with excitation anisotropy, fluorescence lifetimes, and photochemical stability of 1 were investigated in a number of organic solvents at room temperature. The 2PA spectra of 1 with a maximum cross-section of ~ 300 GM were obtained with a 1 kHz femtosecond laser system using open-aperture Z-scan and two-photon-induced fluorescence methods. The transient excited-state absorption (ESA) and gain kinetics of 1 were investigated by a femtosecond pump-probe methodology. Fast relaxation processes (~1-2 ps) in the gain and ESA spectra of 1 were revealed in ACN solution, attributable to symmetry-breaking effects in the first excited state. Efficient superfluorescence properties of 1 were observed in a nonpolar solvent under femtosecond excitation. One- and two-photon fluorescence microscopy imaging of HCT 116 cells incubated with probe 1 was accomplished, suggesting the potential of this new probe in two-photon fluorescence microscopy bioimaging.     

Novel rhodium <Emphasis Type="Italic">N</Emphasis>-heterocyclic carbene catalysed arylation of aldehydes with phenylboronic acid

Reaction of 1,3-dialkylperhydrobenzimidazolinylidene, 1,3-dialkyl-4-methylimidazolinylidene and 1,3-dialkylimidazolinylidene with [RhCl(COD)]₂ yields {1,3-dialkylperhydrobenzimidazolin-2-ylidene}-, {1,3-dialkyl-4-methylimidazolin-2-ylidene}- {1,3-dialkylimidazolin-2-ylidene}chloro(η⁴-1,5-cyclooctadiene)rhodium(I) complexes (2a–c) and (4a, b). All compounds synthesised were characterised by elemental analysis, n.m.r. spectroscopy. Phenylboronic acid reacts with aldehydes in the presence of a catalytic amount of the new rhodium(I)–carbene complexes (2a–c) and (4a, b), to give the corresponding aryl secondary alcohols in good yield (73–99%).