Rotation Of Phenyl Group Research Articles

Stepwise Operation of a Molecular Rotary Motor Driven by an Appel Reaction.

To date, only a small number of chemistries and chemical fueling strategies have been successfully used to operate artificial molecular motors. Here, we report the 360° directionally biased rotation of phenyl groups about a C-C bond, driven by a stepwise Appel reaction sequence. The motor molecule consists of a biaryl-embedded phosphine oxide and phenol, in which full rotation around the biaryl bond is blocked by the P-O oxygen atom on the rotor being too bulky to pass the oxygen atom on the stator. Treatment with SOCl2 forms a cyclic oxyphosphonium salt (removing the oxygen atom of the phosphine oxide), temporarily linking the rotor with the stator. Conformational exchange via ring flipping then allows the rotor and stator to twist back and forth past the previous limit of rotation. Subsequently, the ring opening of the tethered intermediate with a chiral alcohol occurs preferentially through a nucleophilic attack on one face. Thus, the original phosphine oxide is reformed with net directional rotation about the biaryl bond over the course of the two-step reaction sequence. Each repetition of SOCl2-chiral alcohol additions generates another directionally biased rotation. Using the same reaction sequence on a derivative of the motor molecule that forms atropisomers rather than fully rotating 360° results in enantioenrichment, suggesting that, on average, the motor molecule rotates in the "wrong" direction once every three fueling cycles. The interconversion of phosphine oxides and cyclic oxyphosphonium groups to form temporary tethers that enable a rotational barrier to be overcome directionally adds to the strategies available for generating chemically fueled kinetic asymmetry in molecular systems.

Spectroscopic and DFT study of tris(β-diketonato)cobalt(III) complexes

Nuclear magnetic resonance measurements confirm that, as expected, the mer isomer of tris(β-diketonato) cobalt(III) complexes is more stable ( mer isomers are more stable because they are less affected by steric hindrance and they have lower dipoles). An excess of the mer isomer or only the mer isomer is experimentally observed. The existence of both fac and mer isomers is predicted by density functional theory calculations. At room temperature, the nuclear magnetic resonance peaks of phenyl-containing mer complexes are broad due to the intermediate rotation of bulky phenyl groups resulting in only the average orientation of the non-equivalent protons in the mer complexes. However, upon heating to 55 °C (thus speeding up the rotation) or cooling to −50 °C (slowing down the rotation), this broad peak is resolved into three sets of carbon peaks appearing in the 13C NMR spectrum, as well as splitting of the 1H NMR peaks for the non-equivalent protons in the mer isomer. In solid-state 13C NMR the aromatic rings do not rotate, resulting in the splitting of all the 13C NMR peaks. Two sets of well-defined peaks are observed for the fluorine-containing compound [Co(CF3COCHCOCPh)3] in both the 13C and 19F NMR spectra, indicating that both the fac and mer isomers are present with a ratio of fac:mer = 0.1:1. The X-ray photoelectron spectroscopy measured binding energy of the Co 2p3/2 photoelectron lines are influenced by the subtle electronic (electron-donating or electron-withdrawing) properties of the R groups on the β-diketonato ligands. Various relationships are established between the binding energy of Co 2p3/2 and several physical and density functional theory–calculated properties, confirming good electronic communication (the measurable electronic effect that a molecular fragment has on the physical properties of another molecular fragment in the molecule) of the substituent groups through the pseudo aromatic system of the β-diketonato backbones to the metal.

Deciphering the ultrafast dynamics of a new tetraphenylethylene derivative in solutions: charge separation, phenyl ring rotation and CC bond twisting.

Tetraphenylethylene (TPE) derivatives are one of the fundamental units for developing aggregation induced emission (AIE) scaffolds. However, the underlying mechanisms implicated in the relaxation of the excited TPE remain a topic of ongoing discussion, while the effect of bulky substituents on its photobehaviour is still under scrutiny. Here, we report a detailed study of the photophysical properties of a new symmetrical and bulky TPE derivative with terphenyl groups (TTECOOBu) in solvents of different polarities and viscosities. Using femto- to nanosecond (fs-ns) time-resolved absorption and emission techniques, we elucidated the role of the phenyl group rotations and core ethylene bond twisting in its behaviour. We demonstrate that TTECOOBu in DCM solutions undergoes a 600 fs charge separation along the ethylene bond leading to a resonance structure with a lifetime of ∼1 ns. The latter relaxes via two consecutive events: a twisting of the ethylene bond (∼ 9 ps) and a rotation of the phenyl rings (∼ 30 ps) leading to conformationally-relaxed species with a largely Stokes-shifted emission (∼ 12 500 cm-1). The formation of the red-emitting species clearly depends on the solvent viscosity and rigidity of the medium. Contrary to the photobehavior in the highly viscous triacetin or rigid polymer matrix of PMMA, a reversible mechanism was observed in DCM and DMF solutions. These results provide new findings on the ultrafast mechanisms of excited TPE derivatives and should help in the development of new molecular rotors with interesting AIE properties for photonic applications.

Construction of sublimable pure organic ionic material with high solid luminescence efficiency based on anion-π+ interactions tuning strategy

Charged species with π-conjugated moieties play a vital role in the development of organic electronic field, but the executable strategy of attaining high luminescent efficiency with sublimable pure organic salts is rare due to their inherent ionic nature and low vapor pressure, extremely restricting their application in the field of organic optoelectronics via common vacuum evaporation method. In this work, a series of central-type organic salts based polycyclic aromatic hydrocarbon (PAH) core are developed because of their potential higher luminescence efficiency than that of reported terminal-type organic salts like protonated pyridine framework, and they are equipped with aggregation-induced emission enhancement performance and tunable emission. The analyses of spectral data, crystal packing, and theoretical simulation demonstrate that rationally dispersing surface charge of large π cation by regulating donor–acceptor (D-A) distribution facilitates to increase anion-π+ interactions and suppress the free rotation of phenyl groups, contributing to the fluorescence enhancement in the solid state. Notably, after tuning counter-ions’ steric hindrance and dispersed charges (BArF24−), the sublimable pure organic ionic materials are obtained with high solid luminescence efficiency, and its vacuum-evaporated organic light-emitting diode (OLED) is prepared based on pure organic salt with bright yellow emission. Such inspiring results offer us new alternative material system for the organic optoelectronics.

Электронное строение и спектрально-флуоресцентные свойства лазерных красителей тиопирило-4-трикарбоцианинов

It was found that the long-wavelength absorption band of the laser dye IR 1061 and its analogue with an unsubstituted polymethine chain is strongly broadened and decreases in intensity in polar solvents, while the fluorescence band remains narrow and practically does not change in a wide range of solvent polarities. Based on the quantum-chemical calculations of these dyes by the ab initio DFT/B3LYP/6-31G (d,p) and TDDFT methods, taking into account the polarity of the medium by the PCM method, it is shown that the reason for this difference is the weakening of solvation in the fluorescent state as compared to the ground state due to the greater equalization of the charge in the first than in the latter. An increase in the alternation of bond orders in the polymethine chain in the fluorescent state was found, which causes an increase of vibronic interactions in the radiative transition as compared to the absorptive one. Spectral effects caused by a change in the angle of rotation of phenyl groups in the thiopyrylium cycle upon excitation have been analyzed.

Diversiform Nanostructures Constructed from Tetraphenylethene and Pyrene-Based Acid/Base Controllable Molecular Switching Amphiphilic [2]Rotaxanes with Tunable Aggregation-Induced Static Excimers.

Dual-emissive tetraphenylethene (TPE) and pyrene-containing amphiphilic molecules are of great interest because they can be integrated to form stimuli responsive materials with various biological applications. Herein, we report the study of mechanically interlocked molecules (MIMs) with aggregation-induced static excimer emission (AISEE) property through a series of TPE and pyrene-based amphiphilic [2]rotaxanes, where t-butylcalix[4]arene with hydrophobic nature was used as the macrocycle. Evidently, by adorning TPE and pyrene units in [2]rotaxanes P1, P2, P1-b, and P2-b, they display remarkable emission bands in 70% of water fraction (fw) in tetrahydrofuran (THF)/water mixture, which could be attributed to the restricted intramolecular rotation of phenyl groups, whereas prominent blue-shifted excimer emission of pyrene started to appear as fw reached 80% for P1 and 90% for P1-b, P2, and P2-b, which was ascribed to the favorable π-π stacking and hydrophobic interactions of the pyrene rings that enabled their static excimer formation. The well-defined distinct amphiphilic nanostructures of [2]rotaxanes including hollowspheres, mesoporous nanostructures, spheres, and network linkages can be driven smoothly depending on the molecular structures and their aggregated states in THF/water mixture. These fascinating diversiform nanostructures were mainly controlled by the skillful manner of reversible molecular shuttling of t-butylcalix[4]arene macrocycle and also the interplay of multinoncovalent interactions. To further understand the aggregation capabilities of [2]rotaxanes, the human lung fibroblasts (MRC-5) living cell incubated with either P1, P2, P1-b, or P2-b was studied and monitored by confocal laser scanning microscopy. The AISEE property was achieved at an astonishing level by integrating TPE and pyrene to MIM-based reversible molecular switching [2]rotaxanes; furthermore, distinct nanostructures, especially hollowspheres and mesoporous nanostructures, were observed, which are rarely reported in the literature but are highly desirable for future applications.

Crystal structures, Hirshfeld surface analysis and PIXEL calculations of four (E)-1-(2-hydroxyphenyl)-3-phenylprop-2-en-1-one derivatives, containing methoxy substituents. The importance of π interactions

A detailed structural analysis has been carried out on four chalcone (E)-1-(2-hydroxyphenyl)-3-phenylprop-2-en-1-one derivatives, having a varying number of methoxy substituents, namely (E)-3-(3,4-dimethoxyphenyl)-1-(2-hydroxyphenyl)prop-2-en-1-one, (1), (E)-3-(4-methoxyphenyl)-1-(2-hydroxy-4-methoxyphenyl)prop-2-en-1-one, 2, (E)-3-(2,5-dimethoxyphenyl)-1-(2-hydroxy-4-methoxyphenyl)prop-2-en-1-one, 3, and (E)-3-(2,5-dimethoxyphenyl)-1-(2-hydroxy-3,4-dimethoxyphenyl)prop-2-en-1-one, 4. Crystal structures were determined at 100 K by single crystal X-ray diffraction. Compound 2 displayed an unexpectedly large interplanar angle of 25 and 28,o between the phenyl groups in the two independent molecules, due to the formation of a dimeric substructure requiring a pronounced phenyl group rotation to minimise steric hindrance. Such a substructure was absent in 1, 3 and 4. In all cases the 2-hydroxyl substituent forms intramolecular hydrogen bonds with its neighbouring carbonyl group. Different combinations of C–H⋯O, C–H···π and/or π ···π interactions are displayed by 1, 3 and 4, with also CO··· π intermolecular interactions present in 2. The relative contributions of various intermolecular contacts in these structures were investigated using Hirshfeld surfave analysis and the associated two dimensional fringerprint plots. Important molecule pairs were identified in the crystal structures using the PIXEL method. The PIXEL lattice energy calculations revealed that in all cases the dispersion contribution was the major contributor to the packing stabilization, followed by the Coulombic contribution.A search of structures of alkoxy derivatives of (E)-1-(2-hydroxyphenyl)-3-phenylprop-2-en-1-one derivatives in the CCDC data base has also been carried out.

The Effect of Phenyl Substitutions on Microstructures and Dynamics of Tetraalkylphosphonium Bis(trifluoro- methylsulfonyl)imide Ionic Liquids.

Extensive atomistic simulations demonstrated that a gradual substitution of hexyl chains with phenyl groups in tetraalkylphosphonium cations results in remarkable changes in hydrogen bonding interactions, liquid structures and scattering structural functions, and rotational dynamics of hexyl chains and phenyl groups in tetraalkylphosphonium bis(trifluoromethylsulfonyl)imide ionic liquids. Hydrogen donor sites in hexyl chains present competitive characteristics with those in phenyl groups in coordinating anions, as well as their continuous and intermittent hydrogen bonding dynamics. Cation-cation and anion-anion spatial correlations show concomitant shift to short distances with decreased peak intensities with variations of cation structures, whereas cation-anion correlations have a distinct shift to large radial distances due to decreased associations of anions with neighboring cations. These microstructural changes are qualitatively manifested in shifts of prominent peaks for prevalent charge alternations and adjacency correlations between ion species in scattering structural functions. Meanwhile, rotational dynamics of hexyl chains speed up, which, in turn, slow down rotations of phenyl groups, whereas anions exhibit imperceptible changes in their rotational dynamics. These computational results are intrinsically correlated with conformational flexibilities, molecular sizes, and steric hindrance effects of phenyl groups in comparison with hexyl chains, and constrained distributions of anions around cations in heterogeneous ionic environments.

Luminescent Metallacycle-Cored Liquid Crystals Induced by Metal Coordination.

Two rhomboidal metallacycles based on metal-coordination-driven self-assembly are presented. Because metal-coordination interactions restrict the rotation of phenyl groups on tetraphenylethene units, these metallacycles were emissive both in solution and in solid state, and their aggregation-induced emission properties were well-retained. Moreover, the rhomboidal metallacyclic structures offer a platform for intermolecular packing beneficial for the formation of liquid crystalline phases. Therefore, although neither of building blocks shows mesogenic properties, both thermotropic and lyotropic (in DMF) mesophases were observed in one of metallacycles, indicating that mesophases could be induced by metal-coordination interactions. This study not only reveals the mechanism for the formation of cavity-cored liquid crystals, but also provides a convenient approach to preparing supramolecular luminescent liquid crystals, which will serve as good candidates for chemo sensors and liquid crystal displays.

Terpyridyl-based triphenylamine derivatives with aggregation-induced emission characteristics for selective detection of Zn2+, Cd2+ and CN− ions and application in cell imaging

Two terpyridyl triphenylamine derivative luminogens (DTPy-TPA and TPy-TPA) with aggregation-induced emission (AIE) characteristics were designed and synthesized. The number of terpyridyl units of these two compounds has a remarkable effect on the responses towards metal ions. DTPy-TPA with two terpyridyl groups on both sides displayed multi-response to Zn2+ and Cd2+ in THF solution along with distinct absorption and emission spectral changes, and obvious naked-eye color changes. However, TPy-TPA with one terpyridyl phenyl group didn't work. This should be resulted from the formation of supramolecular polymers or oligomers for DTPy-TPA to restrict the intramolecular motions, but dimers for TPy-TPA. Moreover, both of these two compounds in H2O/THF (9:1, v:v) solution could selectively and sensitively detect CN− with distinct fluorescence quenching, which was attributed to the nucleophilic addition of CN− to the α-position of the dicyanovinyl group and thus the free rotation of phenyl groups on TPA. The sensing mechanism of DTPy-TPA or TPy-TPA with CN− was confirmed by 1H NMR titration and Job's plot. Finally, based on their excellent photophysical properties, these two probes were successfully employed to detect CN− in living HEK293 cells using fluorescence bioimaging.

Phenyl rotation barrier in Z‐azobenzene: A physical organic problem in honor of J.D.R.

AbstractThe Z isomer of azobenzene exhibits nonbonded interactions between ortho substituents on adjacent phenyl groups. For o,o′‐difluoroazobenzene derivatives, through‐space 19F‐19F spin‐spin coupling is observed. The coupling constant decreases as the nuclear magnetic resonance probe temperature is decreased culminating in collapse to a single peak. We have used density functional theory and X‐ray crystallography to argue that phenyl group rotation is responsible for this loss of through‐space coupling. We experimentally measured phenyl rotation barriers in the range of 37 to 44 kJ/mol for o,o′‐difluoroazobenzene derivatives. These rotation barriers are qualitatively similar to literature experimental values for fluxional systems but higher than calculated values for Z‐azobenzene.This is the only project in 35 years that I discussed with J.D.R. This mechanistic interpretation of an unusual nuclear magnetic resonance phenomenon is a classic physical organic investigation inspired by my training with Roberts. I tell this scientific story interwoven with a few observations about working with Roberts.

Twist of C═C Bond Plays a Crucial Role in the Quenching of AIE-Active Tetraphenylethene Derivatives in Solution

Aggregation-induced emission (AIE) has emerged as a new class of attractive photoluminescence behavior. Understanding the precise mechanism of the AIE phenomenon will lead to the rational molecular design of novel molecules with AIE properties (AIEgens). In this work, we selected disubstituted derivatives of tetraphenylethene (TPE), a well-known archetypal AIEgen, as the model compounds to elucidate the AIE mechanism. As the result of photochemical experiments and quantum chemical computations, π-bond twist (π twist), including E–Z isomerization (EZI), was found to be the major factor for quenching the photoexcited state of TPE derivatives in the solution state, differently from the well-accepted propeller-like rotation of the side phenyl groups in earlier research. In photochemical experiments, the prepared TPE derivatives exhibited EZI in the solution state upon photoirradiation, and a negative correlation was observed between this isomerization and the AIE phenomenon. The theoretical computations verif...

Structural and stereochemical nonrigidity of 7-(heptaphenylcycloheptatrienyl) isothiocyanate

By means of DFT B3LYP/6-31G(d, p) calculations of 7-(heptaphenylcycloheptatrienyl) isothiocyanate, the dissociation–recombination mechanism for intramolecular migrations of the isothiocyanato group has been revealed, and the structure of the transition state preceding the formation of a tight ion pair has been found for the first time. According to calculations, the high activation barrier for displacements of the isothiocyanato group ΔEZPE≠ = 21.3 kcal/mol is related to the stable conformation of the molecule with the equatorial–NCS group and the orthogonally located phenyl substituent in the axial position. The rearrangement of the molecule to the form favorable for migrations of the–NCS group involves the inversion of the seven-membered ring accompanied by rotation of the phenyl group.

Synthesis and Structure of N‐Hetero‐ortho‐phenylene Hexamers Containing 2,3‐Substituted Pyridine Moieties

AbstractN‐Hetero‐ortho‐phenylene hexamers with two 2,3‐substituted pyridine moieties (i.e., 1a–c) were prepared by palladium‐catalyzed homocoupling with pyridine‐directed C–H cleavage as the key step. The conformations of the resulting hexamers in solution and in the solid state were investigated by computational methods, X‐ray analysis, and 1H NMR spectroscopy. Calculations at the SCS‐MP2/def2‐TZVPP//B97‐D3(bj)/def2‐SVP level suggested that helical folding of 1a as the pyridine moieties are stacked is thermally more stable than the equivalent folding in the unsubstituted ortho‐phenylene hexamer. The conformations of single crystals of 1 were consistent with the optimized structures obtained by DFT calculations. Except for rotation of the terminal phenyl groups, only one set of signals corresponding to a helical conformation was observed by analysis of 1 by 1H NMR spectroscopy in CDCl3 solution.

Memory chromic polyurethane with tetraphenylethylene

ABSTRACTThis article reports a chromic polymer, which is responsive to its shape memory properties and has both the behavior of shape memory polymers and chromic materials. We employed a strategy to fabricate such a smart material, which represents a new principle for making chromic materials. This material is made of shape memory polyurethane with tetraphenylethylene units (0.1 wt %) covalently connected to the soft‐segments (PCL, Mw = 4000). The material displays biocompatibility, shape fixity of 88–93%, and almost 100% shape recovery and has reversible mechanochromic, solvatochromic, and thermochromic shape memory effect. The memory chromism represented by the reversible change of emission intensity shows negative correlation with shape fixity, temperature, and existence of solvent. It may be explained that when the soft segments are molten or dissolved in solvent, the shape recovery switch is open, the AIE units are free from crystal binding and can migrate easily to larger areas, thus the AIE units/particles are far apart from each other and the barrier for rotation of phenyl groups is reduced, which lead to the reduction of emission intensity, appeared by no colors or pale colors, and vice versa. Since the switch is a fundamental structural character of SMPs, the shape memory properties have led to the chromism and we call this memory chromic. © 2013 Wiley Periodicals, Inc. J. Polym. Sci. Part B: Polym. Phys. 2014, 52, 104–110

Theoretical Insight into the Origin of Large Stokes Shift and Photophysical Properties of Anilido‐Pyridine Boron Difluoride Dyes

The geometric and electronic structures and photophysical properties of anilido-pyridine boron difluoride dyes 1-4, a series of scarce 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) derivatives with large Stokes shift, are investigated by employing density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations to shed light on the origin of their large Stokes shifts. To this end, a suitable functional is first determined based on functional tests and a recently proposed index-the charge-transfer distance. It is found that PBE0 provides satisfactory overall results. An in-depth insight into Huang-Rhys (HR) factors, Wiberg bond indices, and transition density matrices is provided to scrutinize the geometric distortions and the character of excited states pertaining to absorption and emission. The results show that the pronounced geometric distortion due to the rotation of unlocked phenyl groups and intramolecular charge transfer are responsible for the large Stokes shift of 1 and 2, while 3 shows a relatively blue-shifted emission wavelength due to its mild geometric distortion upon photoemission, although it has a comparable energy gap to 1. Finally, compound 4, which is designed to realize the rare red emission in BODIPY derivatives, shows desirable and expected properties, such as high Stokes shift (4847 cm(-1)), red emission at 660 nm, and reasonable fluorescence efficiency. These properties give it great potential as an ideal emitter in organic light-emitting diodes. The theoretical results could complement and assist in the development of BODIPY-based dyes with both large Stokes shift and high quantum efficiency.

Molecular motion in zinc hydrazone grid complexes

Four new grid forming hydrazone ligands substituted with methoxy and dimethylamino groups were synthesised. Combination of these ligands with zinc triflate in acetonitrile resulted in self-assembly to form grids as indicated by 1H NMR and ES-MS. 1H NMR also showed thermally induced rotation of the intercalated phenyl ring in both the new grids, and in three previously reported grid compounds. Of these seven, five were amenable to study by variable temperature 1H NMR. Though the observed rates varied by more than an order of magnitude depending upon ligand structure and level of deprotonation, activation energies were similar (∼60 kJ/mol) for all complexes studied. This suggests a model in which dissociation of the central pyrimidine ligand precedes phenyl group rotation with an enthalpy of dissociation near zero. The rate of rotation of the phenyl ring increases with an introduction of electron-donating substituents on the phenyl ring, possibly due to an increased repulsion between π systems.

Chiral bicyclo[3.3.1]-3,7-dioxanonane derivatives: Study of crystallization mode and conformational dynamics in solution

A homologous series of chiral bis-ketals and mixed hemiketal-ketals with rigid bicyclo[3.3.1]-3,7-dioxanonane skeleton has been prepared. The crystallization mode (conglomerate or racemic compound) was established by chiral HPLC with double UV/polarimetric detection. The study of the solid-state structure by single crystal X-ray diffraction disclosed interesting CH⋯π intermolecular interactions. Hindering of rotation of phenyl groups at (hemi)ketalic centres was found to occur. A 1H–DNMR study gave activation barriers Δ G # of 15.9 kcal mol −1 in the ketalic moiety and 10.3 kcal mol −1 in the hemiketalic moiety. The experimental results were substantiated by MM and DFT calculations for ground and transition states.

Reversible Single Molecular Switch Operating at 300 K on a Surface

A single 4-pyridylazobenzene molecule is observed at room temperature on a Si(111)-B surface by using scanning tunnel microscopy. The reversible conformational switching of this molecule is induced by tunneling electrons and observed at room temperature. This process is based on an intramolecular rotation of a single phenyl group without isomerization of the N=N double bond.

About the activation energies of the main and secondary relaxations in cured styrene butadiene rubber

AbstractThis article studies the influence of the network structure on the activation energies of the α and β relaxations in vulcanized styrene butadiene rubber, SBR. A cure system based on sulphur and TBBS (N‐t‐butyl‐2‐benzothiazole sulfenamide) was used in the formulation of several compounds cured at 433 K. The activation energies were evaluated from internal friction (loss tangent) data of the compounds using an automated subresonant forced pendulum in a wide frequency range and between 80 K and 273 K. The internal friction data of the samples reveal two transitions, α and β, characterized by the temperatures Tα and Tβ, due to the glass transition and the phenyl group rotation of the copolymer, respectively. Although Tα increases at higher crosslink density, it shows also a dependence with the amount of polysulphide and monosulphide linkages present in the samples. The highest activation energy for this process is obtained for the samples with high crosslink density and 30% of monosulphides in this structure. In the case of the β‐relaxation, there is a pronounced change in the activation energy between the uncured and the cured samples. The type of structure formed during vulcanization has an important effect in the activation energy of the segmental mode‐process. In the case of the β‐process, the cis‐trans isomerization that takes place during vulcanization in the butadiene part of the SBR, might be the cause of conformational changes in the surrounding of the phenyl rings that affect the energy barrier associated to the phenyl rotation. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009