The rotational spectrum of propynyl isocyanide

Propynyl isocyanide, CH₃C₂NC, has been prepared by vacuum pyrolysis of pentacarbonyl-(1,2-dichloropropenyl isocyanide) chromium, (CO)₅Cr–CN–C(Cl)=C(Cl)CH₃, and its ground state millimeter and microwave spectrum has been observed for the first time. r_s structural parameters of this molecule with a C_3v symmetry could be obtained from the rotational constants of several isotopomers: r_(C1–C2)=1.456(2) Å, r_(C2–C3)=1.206(2) Å, r_(C3–N)= 1.316(2) Å, r_(N–C4)= 1.175(2) Å, r_(H–C1)= 1.090(1) Å, >HCC=110.7(4)°. The nitrogen quadrupole coupling constant has been determined to be 878(2) kHz and measurements of the Stark effect allowed to obtain an electric dipole moment of 4.19(3) Debye. The results fit well into a series of related compounds and are in good agreement with data from ab initio calculations.     

The rotational spectrum and heavy-atom-planar structure of propargyl benzene (3-phenyl-1-propyne)

The microwave rotational spectrum of propargyl benzene has been studied and its stable conformation has coplanar carbon atoms. This planar structure is confirmed independently by the value of its P_cc second moment consistent with only a pair of H atoms out of the plane, by its rotational spectrum obeying a- and b-type and not c-type selection rules, by its display of spectra of nine rather than six distinguishable monosubstituted ¹³C isotopomers, by the absence of tunneling splittings, and by the insensitivity of P_cc to ¹³C isotopic substitution. This conformation is also observed in its isoelectronic analogue, benzyl cyanide. The structure is stabilized by an effective hydrogen bond between an ortho C-H and the π electrons of the triple bond.     

双核镉配聚物及其衍生物荧光光谱的密度泛函理论研究

采用DFT-B3LYP/6-31+G(d)方法,对配聚物[Cd2Cl4(Hbm)2]及其6种衍生物([M2-Cl4(HbmL)2],M=Zn2+,Hg2+;L=-CH3;-NH2;-CN)基态结构进行优化,用TD-DFT/B3LYP/6-31+G(d)方法计算其吸收光谱;同时用HF-CIS/6-31G(d)方法优化其最低激发单重态的几何结构,用含时密度泛函理论计算发射光谱.结果表明:电子在基态与激发态间的跃迁,主要是在卤素配体Cl到金属离子M的电荷转移(LMCL);发射光谱峰的计算最大值与实验值基本符合.改变中心金属离子M和咪唑环上的5位取代基可以精细地调控发光材料的光谱波段.     

The rotational spectrum and structure of the phosphine-hydrogen cyanide complex

The rotational spectrum of the weakly bound complex (PH₃, HCN) in its vibrational ground state has been observed by the technique of pulsed-nozzle, Fourier-transform microwave spectroscopy. The isotopic species (PH₃, HC¹⁴N), (PH₃, DC¹⁴N) and (PH₃, HC¹⁵N) exhibit spectra of the symmetric-top type from which accurate values of the spectroscopic constants B₀, D_J, D_JK and X_aa(¹⁴N) have been determined. For (PH₃, HC¹⁴N) the appropriate values are: B₀ = 1553.3709(1) MHz, D_J = 3.306(3) kHz, D_JK = 256.9(6) kHz and X_aa(¹⁴N) = ?4.3591(14) MHz. The geometry of the complex established from the spectroscopic constants is one of C_3v symmetry at equilibrium, with the HCN molecule lying along the C₃ axis of PH₃ and oriented so that it forms a hydrogen bond to the P atom. The effective distance from P to the C nucleus is r(P ? C) = 3.913 Å.     

Crystal structure and fluorescence spectrum of the complex [Eu(III)(TTA)3(phen)]

The title complex Eu(III)(TTA)₃(phen) (where TTA = thenoyltrifluoroacetone monoanion; phen = 1,10-phenanthroline) has been synthesized in mixed solvents of acetone and ethanol (1:1 volume ratio) and its crystal structure has been determined by X-ray diffraction. The complex crystals are triclinic, space group P 1 (# 2) with cell dimensions of a = 1.32.41 (2) nm, b = 1.5278(4) nm, c = 0.9755(3) nm, α = 92.49 (2)°, β = 102.57(2)°, γ = 91.62(2)°, V = 1.9268(8) nm³, Z = 2, μ (Mo Ka)= 18.77 cm^?1, D_x=1.720 g/cm³. The coordination geometry of Eu atom is a distorted square antiprism, and the encapsulated structure that can meet the structural requirement of the typical europium luminescent sensor. The fluorescence spectrum suggests that the complex is a strong photoluminescent material.     

Theoretical Study on the Rotational Spectra of Ar-D232S Complex

We report a theoretical study on the rotational spectra of Ar-D232S. The intermolecular po- tential energy surface was transformed from our latest ab initio three-dimensional potential of Ar-H232S. The rotational energy levels and wavefunctions of the complex were calcu- lated by using the radial discrete variable representation/angular finite basis representation method and the Lanczos algorithm. The calculated rotational transition frequencies and structural parameters were found to be in good agreement with the available experimental values.     

Experimental and theoretical studies of a silver complex of O-functionalized N-heterocyclic carbene

Experimental and theoretical studies of a silver complex namely, [1-i-propyl-3-(2-oxo-2-t-butyl ethyl)imidazol-2-ylidene]AgCl (1b), supported over an O-functionalized N-heterocyclic carbene ligand are reported. Specifically, [1-i-propyl-3-(2-oxo-2-t-butyl ethyl)imidazol-2-ylidene]AgCl (1b) was synthesized by reaction of 1-i-propyl-3-(2-oxo-2-t-butyl ethyl)imidazolium chloride 1a with Ag₂O in 42% yield. The 1-i-propyl-3-(2-oxo-2-t-butyl ethyl)imidazolium chloride 1a was synthesized by the alkylation reaction of 1-i-propylimidazole with α-chloropinacolone in 70% yield. The molecular structures of 1a and 1b have been determined by X-ray diffraction. Detailed theoretical investigation has been performed using the density functional theory method with the B3LYP functional. Bonding in 1b has been probed with the help of charge decomposition analysis (CDA), atoms in molecule (AIM) approach as well as natural bond orbital (NBO) methods. The Ag-NHC bond has a dominantly covalent character with NHC acting as an effective σ-donor. The π-back-bonding from the metal to the ligand was found to be negligible.     

The rotational spectrum of CN-

The rotational spectrum of the molecular negative ion CN(-) has been detected in the laboratory at high resolution. The four lowest transitions were observed in a low pressure glow discharge through C(2)N(2) and N(2). Conclusive evidence for the identification was provided by well-resolved nitrogen quadrupole hyperfine structure in the lowest rotational transition, and a measurable Doppler shift owing to ion drift in the positive column of the discharge. Three spectroscopic constants (B, D, and eQq) reproduce the observed spectrum to within one part in 10(7) or better, allowing the entire rotational spectrum to be calculated well into the far IR to within 1 km s(-1) in equivalent radial velocity. CN(-) is an excellent candidate for astronomical detection, because the CN radical is observed in many galactic molecular sources, the electron binding energy of CN(-) is large, and calculations indicate CN(-) should be detectable in IRC+10216-the carbon star where C(6)H(-) has recently been observed. The fairly high concentration of CN(-) in the discharge implies that other molecular anions containing the nitrile group may be within reach.     

The Fourier transform infrared spectrum of the boron trifluoride–nitrous oxide complex

The Fourier transform infrared spectra of boron trifluoride and nitrous oxide, co-deposited in nitrogen and argon matrices at cryogenic temperatures, have been recorded. Concentration and temperature cycling experiments have established the existence of a 1:1 molecular complex, the spectrum of which is consistent with a structure similar to that of BF₃.N₂O in the gas phase. The structure derived from the infrared spectrum is also consistent with the results of a series of ab initio molecular orbital calculations reported by us recently. The experimental wavenumbers and complex-monomer wavenumber shifts compare reasonably well, by and large, with those predicted by the ab initio calculations.     

A CASSCF and CCI study of the formation of the Ni2(C2H4) complex

Complete active space SCF and contracted CI calculations have been performed on the potential surface of the Ni₂-C₂H₄ complex in the singlet state. The ethene geometry and position relative to Ni₂ was optimized while the Ni-Ni distance was kept fixed at 2.5 Å.Four possible symmetric geometric arrangements were considered, yielding only an end on -bonded structure as bound. This is a consequence of the charge buildup between the nickel atoms and charge depletion at the ends, coupled with electron mobility along the bond axis, in the nickel dimer.The energy minimum corresponds to a C₂H₄ moiety distorted 21% towards a C₂H₆ geometry, with a bond energy o 24.6 kcal/mol at the CCI level and 28.1 kcal/mol with cluster corrections included. The binding is described by a donation backdonation mechanism. These results are discussed in connection with earlier work on Ni(C₂H₄) and Ni₂(C₂H₄) and in connection with experimental work.     

The rotational spectrum of bromoacetyl chloride

The rotational spectrum of bromoacetyl chloride, BrCH₂COCl, has been assigned using a pulsed molecular beam Fourier transform microwave spectrometer. It has been possible to determine the rotational and quartic centrifugal distortion constants of the energetically favoured conformer (anti-periplanar) as well as the complete bromine and chlorine quadrupole coupling tensors including their off diagonal elements for the following isotopomers: ⁷⁹BrCH₂CO³⁵Cl, ⁸¹BrCH₂CO³⁵Cl, ⁷⁹BrCH₂CO³⁷Cl, and ⁸¹BrCH₂CO³⁷Cl. Experimental results are supported by quantum chemical calculations.     

A novel dimeric complex of dysprosium with pyridine-3-carboxylic acid: structure and photophysical properties

A dimeric complex [Dy(NIC)₃(H₂O)₂]₂ (HNIC = pyridine-3-carboxylic acid) has been synthesized. X-ray analysis reveals that it forms a novel dimeric structure through bridged oxygen atoms of carboxylate groups. The title complex crystallizes in space group P2₁/c, with a = 9.560(3), b = 11.601(4), c = 17.731(5)?Å, β = 91.572(4)°, V = 1965.7(10)?ų, D _c = 1.909?Mg/m³, Z = 2, F(000) = 1100, GOF = 0.956, R ₁ = 0.0248. Photophysical properties have been studied with ultraviolet absorption, excitation and emission spectra. The complex exhibits strong blue emission.     

The far-infrared rotational spectrum of the CF radical

The rotational spectrum of CF in its ground electronic state was studied around 1000 GHz, using a tunable far-infrared source. Seven transitions were observed originating from the ²Π_1/2 and ²Π_3/2 substates. The hyperfine and Λ-type splittings were resolved. The results were combined with gas-phase electron resonance and infrared diode laser spectra to determine all pertinent molecular constants.     

The rotational spectrum and structure of HOOOH

Dihydrogen trioxide, HOOOH, which is a species with fundamental importance for understanding the chain formation ability of the oxygen atom, was detected in a supersonic jet by a Fourier transform microwave spectrometer with a pulsed discharge nozzle, together with double resonance and triple resonance techniques. Its precise molecular structure was determined from the experimentally determined rotational constants of HOOOH and its isotopomer, DOOOD. Many of the microwave and millimeter wave transitions can now be accurately predicted, which could be facilitated for remote sensing of the molecule to elucidate its roles in various chemical processes.     

Internal dynamics features in the free jet rotational spectrum of the acetaldehyde-Kr molecular complex

The structure and the dynamics of internal motions in the complex formed between acetaldehyde and Kr are studied by free jet absorption microwave spectroscopy performed in the range 60-78 GHz. The fourfold structure of each rotational line is evidence of the vibration-rotation coupling between the overall rotation of the complex, a tunneling motion of the Kr atom between two equivalent positions and the internal rotation of the methyl group in the acetaldehyde moiety. The four sets of transitions could be fitted with a coupled Hamiltonian which allows for the Coriolis interaction obtaining the energy separation between the vibrational energy levels related to the tunneling motion, while the observed splittings due to the methyl group internal rotation were analyzed independently with an appropriate model. The potential energy barriers for the tunneling motion and the internal rotation of the methyl group have been calculated and the interaction of the rare gas atom with the acetaldehyde moiety is reflected in the change of the V(3) barrier to internal rotation in going from the molecule to the weakly bound complex.     

Fluxional behavior of Al(Et)(q)2 (q=2-methyl-8-quinolinolato) studied by temperature dependent H NMR spectroscopy

Two α-CH₂ hydrogens of the Et group in Al(Et)(q^′)₂ (q^′=2-methyl-8-quinolinolato) show two ¹H NMR peaks at different positions with a separation of 0.19 ppm at 25 °C, due to the presence of a chiral center at Al. On raising the temperature, the two peaks collapsed, and coalesced above 100 °C. The ¹H NMR fluxional behavior is accounted for by simultaneous rotation of the q^′ ligands, and kinetic parameters of kJ mol⁻¹, kJ mol⁻¹, J K⁻¹ mol⁻¹ are evaluated.     

Reactions of Dienes with a Mo(0) Complex with Tetraphosphine Coligand [Mo(P4)(Ph2PCH2CH2PPh2)] (P4 = Meso‐o‐C6H4(PPhCH2CH2PPh2)2)

Reaction of tetraphosphine complex [Mo(κ⁴‐P4)(Ph₂PCH₂CH₂PPh₂)] (1; P4 = meso‐o‐C₆H₄‐(PPhCH₂CH₂PPh₂)₂) with E‐1,3‐pentadiene in toluene at 60 °C gave the η⁴‐diene complex [Mo(η⁴‐E‐1,3‐pentadiene)(κ⁴‐P4)] (2), which is present as a mixture of two isomers due to the orientation of the Me group in the diene ligand. Treatment of 1 with Z‐1,3‐pentadien also resulted in the formation of 2 as the sole product after heating the reaction mixture at 90 °C. Whereas the reaction of 1 with 1,3‐cyclohexadiene at 60 °C afforded the η⁴‐diene complex [Mo(η⁴‐cyclohexadiene)(κ⁴‐P4)] (6), that with cyclopentadiene led to the C‐H bond scission product [η⁵‐C₅H₅)MoH(κ³‐P4)] (7). Detailed structures were determined by X‐ray crystallography for 2, 6,and 7, and fluxional feature of 6 in solution was clarified based on the VT‐NMR studies.     

Binuclear ruthenium(II) pyridazine complex catalyzed transfer hydrogenation of ketones

A convenient and general method of synthesis of binuclear ruthenium(II) pyridazine complex was reported. The synthesized complex was characterized by analytical and spectral methods. The structure of the complex was confirmed by X-ray diffraction technique and was found to be an efficient catalyst for the transfer hydrogenation of ketones with excellent conversions in the presence of isopropanol/KOH at 82 °C. The effect of solvents, bases, and different catalyst/substrate ratio for the reaction was also investigated.     

A study on orientation and absorption spectrum of interfacial molecules by using continuum model

In this work, a numerical procedure based on the continuum model is developed and applied to the solvation energy for ground state and the spectral shift against the position and the orientation of the interfacial molecule. The interface is described as a sharp boundary separating two bulk media. The polarizable continuum model (PCM) allows us to account for both electrostatic and nonelectrostatic solute-solvent interactions when we calculate the solvation energy. In this work we extend PCM to the interfacial system and the information about the position and orientation of the interfacial molecule can be obtained. Based on the developed expression of the electrostatic free energy of a nonequilibrium state, the numerical procedure has been implemented and used to deal with a series of test molecules. The time-dependent density functional theory (TDDFT) associated with PCM is used for the electron structure and the spectroscopy calculations of the test molecules in homogeneous solvents. With the charge distribution of the ground and excited states, the position- and orientation-dependencies of the solvation energy and the spectrum have been investigated for the interfacial systems, taking the electrostatic interaction, the cavitation energy, and the dispersion-repulsion interaction into account. The cavitation energy is paid particular attention, since the interface portion cut off by the occupation of the interfacial molecule contributes an extra part to the stabilization for the interfacial system. The embedding depth, the favorable orientational angle, and the spectral shift for the interfacial molecule have been investigated in detail. From the solvation energy calculations, an explanation has been given on why the interfacial molecule, even if symmetrical in structure, tends to take a tilting manner, rather than perpendicular to the interface.     

Synthesis, spectroscopic characterization and crystal structure of mixed ligand Ni(II) complex of N-4-diethylaminosalicylidine-N′-4-nitrobenzoyl hydrazone and 4-picoline

A novel mixed ligand nickel complex [NiLB] [H₂L-N-4-diethylaminosalicylidine-N′-4-nitrobenzoyl hydrazone and B-4-picoline] has been synthesized and characterized by elemental analysis, IR spectrum, UV-Vis spectrum and structure has been confirmed by single crystal X-ray structure analysis. The crystal structure reveals that the complex adopts distorted square planar structure with ONO donor atoms of primary ligand and N donor atom of the secondary ligand 4-picoline.