Electron-impact coherence parameters for the excitation of the 51 P state of Sr

Electron-photon polarization correlation measurements have been carried out for the excitation of the 5¹P state of Sr at electron impact energies of 30.3 and 58.4 eV and electron scattering angles of 20°–130° for 30.3 eV and 20°–100° for 58.4 eV. The resulting Stokes parametersP ₁,P ₂,P ₃ are used to derive the usual complete scattering parameter sets λ, χ and γ,L _⊥,P _l. New FOMBT calculations for these parameters are reported alongside the measured data and show substantial agreement with the experiment and with recent calculations by Srivastava et al.     

Molecular Structure of Diphenylamine by Gas-Phase Electron Diffraction and Quantum Chemistry

Geometric parameters of the diphenylamine molecule were determined by gas-phase electron diffraction and quantum-chemical calculations. By gas-phase electron diffraction, the molecule has an asymmetric structure with torsion angles about N-C bonds of ?45.6(23)° and 173.4(46)°, which agrees with RHF/6-31G** calculations. Density functional theory (DFT) calculations at the B3LYP/6-31G** level of theory lead to a C ₂ molecular conformation in the ground electronic state. The principal experimental geometric parameters are as follows: bond lengths: C-N 1.417(1), C-C_av 1.403(1) Å; and bond angles: CNC 123.9(5)°, and NCC 121.5° (assumed) and 116.4°.     

The crystal structure of bicyclo [3.3.3]undecane-1,5-diol and the conformation of bicyclo[3.3.3]undecane (manxane)

The crystal structure of bicyclo [3.3.3]undecane-1,5-diol has been determined. It is monoclinic, P2₁/c, a = 12.99(2), b = 14.16(2), c = 12.50(1)A,β = 112.42(2)°, with two independent molecules in the asymmetric unit. One of these is disordered, but the other has almost exact C_3h symmetry and its conformation and precise molecular geometry agree well with previous calculations by molecular mechanics. The molecule shows considerable angle strain, having bridge angles in the range 118–121°     

The <Emphasis Type="Italic">r</Emphasis><Subscript>0</Subscript> structural parameters of equatorial and axial chlorocyclobutane,conformational stability from temperature dependent infrared spectra of xenon solutions,and vibrational assignments

Variable temperature (?55 to ?100 °C) studies of the infrared spectra (4,000–400 cm^?1) of chlorocyclobutane, c-C₄H₇Cl, dissolved in liquid xenon have been carried out. The infrared spectrum (4,000–100 cm^–1) of the gas has also been recorded. For this puckered ring molecule the enthalpy difference between the more stable equatorial conformer and the axial form, has been determined to be 361 ± 17 cm^?1 (4.32 ± 0.20 kJ/mol). This stability order is consistent with that predicted by ab initio calculations but the ?H is much lower than the average energy value of 646 ± 73 cm^?1 obtained from the MP2 ab initio calculations or 611 ± 28 cm^?1 from the B3LYP density functional theory calculations. The percentage of the axial conformer present at ambient temperature is estimated to be 15 ± 1%. By utilizing previously reported microwave rotational constants for both conformers combined with ab initio MP2(full)/6–311+G(d,p) predicted structural values, adjusted r ₀ parameters have been obtained. The determined heavy atom structural parameters for the equatorial conformer are: the distances C–Cl = 1.783(5), C₁–C₄ = 1.539(3), C₄–C₆ = 1.558(3) Å, and angles ∠C₆C₄C₁ = 86.9(5), ∠C₄C₁C₅ = 89.7(5)°, and for the axial conformer are: the distances C–Cl = 1.803(5), C₁–C₄ = 1.547(3), C₄–C₆ = 1.557(3) Å, and angles ∠C₆C₄C₁ = 86.3(5), ∠C₄C₁C₅ = 88.9(5) and the puckering angles for the equatorial and axial conformers are 30.7(5)° and 22.3(5)°, respectively. The conformational stabilities, harmonic force fields, infrared intensities, Raman activities, depolarization ratios and vibrational frequencies have been obtained for both conformers from MP2(full)/6-31G(d) ab initio calculations and compared to experimental values where available. The results are discussed and compared to the corresponding properties of some similar molecules.     

Internal rotation and equilibrium structure of the 2-methyl-2-nitropropane molecule from joint processing of gas phase electron diffraction data,vibrational and microwave spectroscopy data,and quantum chemical calculation results

The structure and internal rotation of the 2-methyl-2-nitropropane molecule is studied by electron diffraction and quantum chemical calculations with the use of microwave and vibrational spectroscopy data. The electron diffraction data are analyzed within the general intramolecular anharmonic force field model and the quantum chemical pseudoconformer model, considering the adiabatic separation of the degree of freedom of large amplitude motion, i.e., the internal rotation of the NO₂ group. The equilibrium eclipsed configuration of the C _s symmetry molecule has the following experimental bond lengths and valence angles: r _e(N=O) = 1.226//1.226(8) Å, r _e(C–N)//r _e(C–C) = 1.520//1.515/1,521(4) Å, ∠_еC–C–N = = 109.1/106,1(8)°, ∠_еO=N=O = 124.2(6)°, ∠_eC–C–H_avg = 110(3)°. The equilibrium geometry parameters are well consistent with MP2/cc-pVTZ quantum chemical calculations and microwave spectroscopy data. The thermally average parameters previously obtained within the small vibration model show a satisfactory agreement with the new results. The electron diffraction data used in this work do not allow a reliable determination of the barrier to internal rotation. However, at a barrier of 203(2) cal/mol, which is derived from the microwave study, it follows from the electron diffraction data that the equilibrium configuration must correspond to an eclipsed arrangement of C–C and N=O bonds, which is also consistent with the results of quantum chemical calculations of various levels.     

Molecular structure and conformation of nitrobenzene reinvestigated by combined analysis of gas-phase electron diffraction,rotational constants,and theoretical calculations

The molecular structure and conformation of nitrobenzene has been reinvestigated by gas-phase electron diffraction (GED), combined analysis of GED and microwave (MW) spectroscopic data, and quantum chemical calculations. The equilibrium r _e structure of nitrobenzene was determined by a joint analysis of the GED data and rotational constants taken from the literature. The necessary anharmonic vibrational corrections to the internuclear distances (r _e ? r _a) and to rotational constants (B _e ⁽ⁱ⁾  ? B ₀ ⁽ⁱ⁾ ) were calculated from the B3LYP/cc-pVTZ quadratic and cubic force fields. A combined analysis of GED and MW data led to following structural parameters (r _e) of planar nitrobenzene (the total estimated uncertainties are in parentheses): r(C–C)_av = 1.391(3) Å, r(C–N) = 1.468(4) Å, r(N–O) = 1.223(2) Å, r(C–H)_av = 1.071(3) Å, \({\angle}\)C2–C1–C6 = 123.5(6)°, \({\angle}\)C1–C2–C3 = 117.8(3)°, \({\angle}\)C2–C3–C4 = 120.3(3)°, \({\angle}\)C3–C4–C5 = 120.5(6)°, \({\angle}\)C–C–N = 118.2(3)°, \({\angle}\)C–N–O = 117.9(2)°, \({\angle}\)O–N–O = 124.2(4)°, \({\angle}\)(C–C–H)_av = 120.6(20)°. These structural parameters reproduce the experimental B ₀ ⁽ⁱ⁾ values within 0.05 MHz. The experimental results are in good agreement with the theoretical calculations. The barrier height to internal rotation of nitro group, 4.1±1.0 kcal/mol, was estimated from the GED analysis using a dynamic model. The equilibrium structure was also calculated using the experimental rotational constants for nitrobenzene isotopomers and theoretical rotation–vibration interaction constants.     

A gas-phase electron diffraction study of the molecular structure of 1,1-difluoroethane

The molecular structure of 1,1-difluoroethane has been studied using gas-phase electron diffraction data collected on the Balzers KDG2 instrument. Effective least-squares refinement of the geometry was achieved with fixed values for vibrational amplitudes transferred from normal coordinate calculations on related molecules. In subsequent calculations, in which several amplitudes were also allowed to refine, only minor changes were noted. The refinements yielded the following main geometrical parameters (r_avalues with e.s.d. in parentheses): C—C = 1.498(4) Å, C—F = 1.364(2) Å, C—H(mean) = 1.081(3) Å, ∠CCH(mean) = 111.0(7)°, ∠CCF = 110.7(3)°, ∠FCF = 107.4(5)°. Dependent angles are ∠FCH = 108.5(8)° and ∠HCH = 107.9(7)°.     

Sulfophthalide cycle cleavage and formation of fluorenyl structures upon poly(diphenylene sulfophthalide) thermolysis

Thermolysis of poly(diphenylene sulfophthalide) (PDSP) in the temperature range from 100 to 500 °C was studied by IR and UV-Vis spectroscopy and thermogravimetric analysis. A series of absorption bands in the IR spectrum of PDSP were assigned on the basis of the theoretical calculations of the IR spectrum of diphenyl sulfophthalide used as a model compound, in particular, ν_as(S=O) = 1352 cm^?1, ν_s(S=O) = 1196 cm^?1, ν(C-O) ～ 920 cm^?1, ν(S-O) = 824 cm^?1, and δ(SO₂) = 576 cm^?1. The sulfophthalide cycle (SPC) in PDSP decomposes at the thermolysis temperatures in a range of 260–400 °C. An analysis of the IR spectra of the thermolyzate and the quantum chemical calculations of the IR spectra of the model compounds confirmed the predominant formation of fluorenyl structures in the thermolyzed polymer. The changes in the UV-Vis spectra observed upon the thermolysis of thin films of PDSP (the hypsochromic shift of the long-wavelength absorption band from 271 to 263 nm and the appearance a shoulder at ～310 nm) and the results of TD-DFT calculations of the UV-Vis spectra of the model compounds are consistent with the hypothesis about the formation of fluorenyl structures. The general scheme of PDSP thermolysis at 260–400 °C was proposed in which the major process is the formation of fluorenyl fragments in macromolecules of the polymer due to the intramolecular ring closure in biradicals formed by the SPC cleavage.     

Crystal and molecular structure of caryophyllene α-oxide

An x-ray study (λMo K^α, 2θ/ω scanning for 2θ<30°, MLS in the anisotropic approximation) has been made of caryophyllene α-oxide (I) at ?(98–100)°C (1182 reflections, R=0.051); crystals of the orthorhombic system,a=8.975, b=10.160, c=14.882 Å, z=4, space group P2₁2₁2₁, mp 62–63°C. The crystalline and molecular structures of caryophyllene α-oxide (I) have been studied and the configuration of the oxide ring has been confirmed.     

Synthesis,crystal structure,and luminescent properties of a new modification of the zinc(II) dichloride complex with phthalazine

The coordination compound [ZnCl₂(Phtz)₂] has been synthesized by the reaction of ZnCl₂ with phthalazine (Phtz, L, C₈H₆N₂) in an ethanol solution. Its crystal structure has been determined: crystals are triclinic, space group P 0000000, a = 7.346(1) Å, b = 8.095(1) Å, c = 14.275(1) Å, α = 85.63(1)°, β = 75.75(1)°, γ = 88.43(1)°, V = 820.4(2) ų, ρ_calc = 1.605 g/cm³, Z = 2. The zinc atom is tetrahedrally coordinated to two crystallographically nonequivalent chlorine atoms and two nitrogen atoms of the ligands L (Zn(1)–N(1), 2.036(4) Å; Zn(1)–N(3), 2.043(4) Å; Zn(1)–Cl(1), 2.225(2) Å; Zn(1)–Cl(2), 2.220(2) Å; angles NZnN, 106.1(2)°; ClZnCl, 116.47(7)°). The complexes are combined into a 1D supramolecular structure by nonclassical hydrogen bonds C–H···Cl and π–π-stacking interaction between centrosymmetric pairs of aromatic rings of one of the independent ligands. The compounds [CdI₂(Phtz)] and [HgBr₂(Phtz)] have also been synthesized, and their luminescent properties have been studied.     

Étude conformationnelle et spectres infrarouges de l'acide glycyl aminométhylphosphonique

Glycyl aminomethylphosphonic acid (Gly AMPh) is studied by X-ray diffraction and IR spectrometry in the solid state. It is shown to exist as the monohydrated zwitterion

,H₂O. Its conformation in the crystal (Pbca space group) is defined by ψ₁ = ?162°, Φ₂ = ?110° and ψ₂ = ?58°. Energy calculations by a semi-empirical method for the isolated zwitterion shows two stable conformations for ψ₁ = ?75°, Φ₂ = ?120° and ψ₁ = +75°, Φ₂ = +120°, gave for ψ₂, = ?60°, the most probable value. Infrared spectra are analysed by means of normal mode calculations.     

Molecular structure of hexafluorobicyclo [2.2.0]hexa-2,5-diene (hexafluoro-dewar-benzene) in the vapour phase

Hexafluoro-Dewar-benzene has been studied by the electron-diffraction method. A model with C_2v symmetry gives excellent agreement between experimental and theoretical data. The structural parameters with error limits are (cf. Fig. 1): r(C₁-C₄)= 1.598 ±0.017 Å, r(C₁-C₂) = 1.505 ±0.005 Å, r(C₂-C₃) = 1.366 ± 0.015 Å, r(C₁-F₁) = 1.328±0.015 Å, r(C₂-F₂) = 1.319±0.007 Å, ∠F₁C₁C₄ = 118.7±0.7°, ∠F₂C₂C₃ = 133.6±0.7°, τ= 121.8±2.0°, and δ = -7.5±2.0°. Molecular orbital calculations by the CNDO/2 method gave τ = 119.8° and δ = ?4.2°.     

Molecular structure of p-diisocyanobenzene from gas-phase electron diffraction and theoretical calculations and effects of intermolecular interactions in the crystal on the benzene ring geometry

In this study, the molecular structure of p-diisocyanobenzene has been determined by gas-phase electron diffraction and quantum chemical calculations. The electron diffraction intensities from a previous study by Colapietro et al. (J Mol Struct 125:19–32, 1984) have been reanalyzed using geometrical constraints and initial values of vibrational amplitudes from computations. The equilibrium structure of the molecule has D _2h symmetry, whereas the average geometry in the gaseous phase is best described by a non-planar model of C _2v symmetry. The lowering of symmetry is due to large-amplitude motion of the substituents out of the plane of the benzene ring. The non-planar model has an internal ring angle at the ipso position, ∠_aC2–C1–C6 = 120.6 ± 0.2°, about 1° smaller than that from the previous study, but consistent with the quantum chemical calculations. The mean length of the ring C–C bonds and the length of the triple bond are accurately determined as 〈r _g(C–C)〉 = 1.398 ± 0.003 Å and r _g(N≡C) = 1.177 ± 0.002 Å, respectively. Comparison with the gaseous isoelectronic molecules p-diethynylbenzene and p-dicyanobenzene shows that the differences in the mean lengths of the ring C–C bonds and in the lengths of the triple bonds determined by electron diffraction are equal or closely similar to the corresponding differences from quantum chemical calculations. The present experimental value of the ipso angle in free p-diisocyanobenzene is slightly, but significantly smaller than that obtained by X-ray crystallography. The difference is confirmed by computational modeling of the crystal structure and appears to be due to –N≡C···H–C intermolecular interactions in the crystal.     

To the Knowledge of Interpseudohalogens: A Contribution to Cyanogen Isocyanate (NC–NCO)

Cyanogen isocyanate (NC–NCO) has been prepared and studied using a combined experimental and theoretical approach. A crystalline film of the interpseudohalogen species was stabilized by vapor deposition on a cold substrate (T = –100 °C). From IR spectroscopy on the “free” molecule, trapped in a matrix of solid argon, the connectivity and geometry of this unstable interpseudohalogen was deduced and substantiated by theoretical calculations. With this information, the crystal structure of NCNCO in the solid state could be analysed using powder X‐ray diffraction [Pbca (No. 61), a = 7.63(1) Å, b = 6.50(2) Å, c = 6.03(6) Å; V = 299.5(1) ų]. The compound transforms into amorphous polymeric C₂N₂O at T > –68 °C. The results obtained were compared with recent findings and further discussed in the general context of C–N–(O) chemistry.     

Kristallstruktur,Phasenumwandlung und Kaliumionenleitfähigkeit von Kaliumtrifluormethylsulfonat

Crystal Structure, Phase Transition, and Potassium Ion Conductivity of Potassium Trifluoromethanesulfonate According to the results of temperature dependent powder diffractometry (Guinier‐Simon‐technique) potassium trifluoromethanesulfonate is dimorphic. The phase transition occurs between –63 °C and –45 °C. The low‐temperature modification crystallizes monoclinic with a = 10.300(3) Å, b = 6.052(1) Å, c = 14.710(4) Å, β = 111.83(2)° (–120 °C) and the room‐temperature modification with a = 10.679(5) Å, b = 5.963(2) Å, c = 14.624(5) Å, β = 111.57(3)°, Z = 6, P2₁. According to single crystal structure determination, potassium trifluoromethanesulfonate consists of three different potassium‐oxygen‐coordination polyhedra, linked by sulfur atoms of the trifluoromethanesulfonate groups. This results in a channel structure with all lipophilic trifluoromethane groups pointing into these channels. By means of DSC, the transition temperature and enthalpy have been determined to be –33 °C and 0.93 ± 0.03 kJ/mol, respectively. The enthalpy of melting (237 °C) for potassium trifluoromethanesulfonate is 13.59 kJ/mol, the potassium ionic conductivity is 3.68 · 10^–6 Scm^–1 at 205 °C.     

Synthesis and structural features of tris(5-bromo-2-methoxyphenyl)antimony dicarboxylates

Tris(5-bromo-2-methoxyphenyl)antimony bis(4-nitrophenylacetate) (I), tris(5-bromo-2-methoxyphenyl)antimony bis(2-methoxybenzoate) (II), and tris(5-bromo-2-methoxyphenyl)antimony bis(phenylpropiolate) (III) have been synthesized via the reaction between tris(5-bromo-2-methoxyphenyl) antimony and 4-nitrophenylacetic acid, 2-methoxybenzoic acid, and phenylpropiolic acid, respectively, in the presence of hydrogen peroxide (molar ratio: 1: 2: 1). According to X-ray diffraction data, the antimony atom in molecules of complexes I–III has a distorted trigonal bipyramidal coordination. The OSbO axial angles and the CSbC bond angles in the equatorial plane are 173.27(15)°, 172.96(11)°, 172.99(10)°, and 115.5(2)°–123.3(2)°, 108.81(16)°–129.32(17)°, and 110.66(17)°–127.91(17)°, respectively. The Sb-O bond lengths are 2.092(4) and 2.115(4)Å in I, 2.088(3) and 2.097(2) Å in II, and 2.096(3) and 2.120(3) Å in III. The Sb-C bonds range within 2.095(6)–2.123(6) Å in I, 2.107(4)–2.117(4) Å in II, and 2.097(4)–2.116(4) Å in III. Complexes I, II, and III are observed to have intramolecular Sb…OCH₃ contacts (3.169–3.226, 3.134–3.174, and 3.147–3.196 Å, respectively) in addition to Sb…O=C interactions (3.121, 3.139Å; 2.944, 3.038 A0; 3.111, 3.120 Å).     

Synthese,Struktur und Reaktionen von Vanadiumsäureestern VO(OR)3: Umesterung und Reaktion mit Oxalsäure

Synthesis, Structure, and Reactions of Vanadium Acid Esters VO(OR)₃: Transesterification and Reaction with Oxalic Acid The reaction of tert.‐Butyl Vanadate VO(O‐tert.Bu)₃ ( 1 ) with H₂C₂O₄ in the primary alcohols ethanol and propanol results in the formation of (ROH)(RO)₂OV^V(C₂O₄)V^VO(OR)₂(HOR) (with R = C₂H₅ 2 and R = C₃H₇ 3 ). Compounds 2 and 3 are the first structurally characterized neutral, binuclear oxo‐oxalato‐complexes with pentavalent vanadium. The two vanadium atoms are connected by a bisbidentate oxalate group. The {VO₆} coordination at each vanadium site is completed by a terminal oxo group, an alcohol ligand and two alcoxide groups. The binuclear molecules are connected to chains by hydrogen bonding. In the case of 2 a reversible isomorphic phase transition in the temperature range of –90 °C to –130 °C is observed. From methanolic solution the polymeric Methyl Vanadate [VO(OMe)₃] ( 4 ) was obtained by transesterification. A report on the crystal structures of 1 , 2 and 3 as well as a redetermination of the structure of 4 is given. Crystal data: 1, orthorhombic, Cmc2₁, a = 16.61(2) Å, b = 9.274(6) Å, c = 10.784(7) Å, V = 1662(2) ų, Z = 4, d_c = 1.144 gcm^–1; 2 (–90 ° C) , monoclinic, I2/a, a = 33.502(4) Å, b = 7.193(1) Å, c = 15.903(2) Å und β = 143.060(3)°, V = 2303(1) ų, Z = 4, d_c = 1.425 gcm^–1; 2 (–130 ° C) , monoclinic, I2/a, a = 33.274(4) Å, b = 7.161(1) Å, c = 47.554(5) Å, β = 142.798(2)°, V = 6851(1) ų, Z = 12, d_c = 1.438 gcm^–1; 3 , triklinic, P1, a = 9.017(5) Å, b = 9.754(5) Å, c = 16.359(9) Å, α = 94.87(2)°, β = 93.34(2)°, γ = 90.42(2)°, V = 1431(1) ų, Z = 2, d_c = 1.340 gcm^–1; 4 , triklinic, P1, a = 8.443(2) Å, b = 8.545(2) Å, c = 9.665(2) Å, α = 103.202(5)°, β = 96.476(5)°, γ = 112.730(4)°, V = 610.2(2)ų, Z = 4, d_c = 1.742 gcm^–1.     

Preparation,crystal structure,and magnetic properties of β-Li3TiF6 = LiLi(TiF6)(TiF6)2 – a double fluoride?

Purple colored single crystals of the β-modification of Li₃TiF₆ have been prepared by heating an appropriate mixture of LiF and TiF₃ at 820°C under an argon atmosphere. β-Li₃TiF₆ crystallizes in C2/c with a = 14.452(2) Å, b = 8.798(1) Å, c = 10.113(1) Å and β = 96.30(1)º. The structure is isotypic to β-Li₃VF₆ and contains isolated compressed TiF₆ octahedra (d_Ti–F = 1.91–2.01 Å). Magnetic properties of β-Li₃TiF₆ were studied and discussed. Band structure calculations and calculations of the Madelung part of the lattice energy, MAPLE, were performed to discuss the chemical bonding.     

Investigations on crystal structure of a novel 3-((4,6-dimethylpyrimidin-2-yl)amino)isobenzofuran-1(3H)-one,and related theoretical studies

In this report, 3-((4,6-dimethylpyrimidin-2-yl)amino)isobenzofuran-1(3H)-one have been synthesized via reaction between phthalaldehydic acid and 2-amino-4,6-dimethylpyrimidine in 90% yields and characterized by Infrared (IR), Nuclear Magnetic Resonance (NMR), Ultraviolet–visible (UV–Vis), X-ray single crystal diffraction techniques. The single-crystal X-ray analysis shows that the title compound crystallizes in the triclinic space group P-1 with unit-cell parameters a = 7.9351(4) Å, b = 11.1687(6) Å, c = 16.1281(9) Å, α = 73.713(5)°, β = 80.362(5)°, γ = 72.882(4)° and Z = 4. A theoretical study with hybrid functional B3LYP 6-311G (d, p) basis set have been used in calculations. The structural and electronic properties have been detailed. The title compound was screened for its antioxidant activity by (1,1-diphenyl-2-picryl hydrazyl) free radical scavenging (DPPH), Ferric ion reducing antioxidant power (FRAP), total phenolic contents (TP) assays and its ferrous ions chelating property. Electronic absorption titration, thermal denaturation measurement and viscosity techniques were used to determine the interaction between double stranded DNA (dsDNA) and compound 1. In three techniques, the mode of binding of compound 1 to dsDNA is minor groove. The UV–Vis measurement results allowed the calculation of the binding constant showing the binding strength of compound 1 to dsDNA was calculated as 8.13 × 10⁴ ± 0.07 L mol⁻¹. Moreover, the molecular docking calculations have been performed to investigate the compound–DNA interactions, computationally. In molecular docking calculations, it was observed that for the title compound, the lowest energy docking pose takes place in the minor groove of DNA and in addition to minor groove binding, interactions between the compound and the consecutive base pairs of DNA which may cause a partial intercalation were also observed. Results showed that title compound – DNA complex is stabilized by several hydrogen bonds, and Pi-alkyl interactions also take part in the stabilization of the complex. Binding affinities of the lowest energy docking pose of the title compound was found to be −8.3 kcal/mol.     

Origin of Spectrum Shifts of Benzophenone–Water Clusters: DFT Study

Structures and electronic excitation energies of the benzophenone–water (Bp–H₂O) and benzophenone–methanol (Bp–CH₃OH) complexes have been investigated by means of density functional theory calculations. The CAM-B3LYP/6-311++G(d,p) and higher level calculations were carried out for the system. The calculations indicate that free Bp has a nonplanar structure with twist angle of 54.2° for two phenyl rings (referred to as ?). In the case of the Bp–H₂O system, the twist angle of the phenyl rings and structure of the Bp skeleton were hardly changed by hydration (? = 55.1° for Bp–H₂O). However, the excitation energies of Bp were drastically changed by this solvation. The time-dependent density functional calculations show that the n–π* transition (S₁ state) is blue-shifted by the solvation, whereas two π–π* transitions (S₂ and S₃) were red-shifted. The origin of the specific spectral shifts is discussed on the basis of the theoretical results.