Vibrational spectra of the charge transfer complexes between organic sulfides and iodine

I.r. spectra of the charge transfer complexes between nine organic sulfides (as well as diethylselenide) with iodine were recorded between 1500 and 400 cm⁻¹ in CS₂ and CCl₄ solutions and in the region 600-50 cm⁻¹ in C₆H₁₂ and C₆H₆ solutions. Raman spectra of the complexes were recorded below 600 cm⁻¹. For each system, i.r. and Raman bands in the 200-160 cm⁻¹ were assigned to the II stretching mode of the complex. Additional i.r. bands below 160 cm⁻¹, absent in Raman, were ascribed to intermolecular SI stretching vibrations. The integral intensities of these bands were determined and correlated with the thermodynamic functions. Some Raman active fundamentals of 1,4-dithiane became i.r. active in the iodine complex in accordance with a break down of the C₂h symmetry. A force constant calculation was carried out for the dimethylsulfide-iodine complex and simplified calculations of the three point mass models were made for all the systems.     

Vibrational spectra of halomethylidynetricobalt nonacarbonyl complexes

Infrared and Raman spectra (1400-100 cm⁻¹) are reported for the metal cluster complexes (μ₃ - YC)CO₃(CO)₉; YF, Cl and Br, and vibrational assignments for the YCCo₃ groupings proposed. Approximate force fields have been calculated for these groups and the results are compared with those derived in earlier work on related systems. The unusually high frequencies attributed to carbon-halogen stretching modes in these complexes are shown to result from appreciable coupling of these modes with the symmetric CoC stretching mode.     

Vibrational spectra of charge transfer complexes of pyridines and halogens:: Part 1. A Laser raman study of the iodine stretching vibration in complexes pyridine .iodine. comparison with pyridine .bromine.

The Raman parameters (frequency, intensity and depolarization ratio) of the ν_II band of charge transfer complexes of iodine with several pyridine derivatives have been studied in dichloromethane solution at 296 °K. Complex formation brings about an enhancement of the intensity and depolarization degree, similar to the results which have previously been published for pyridine.bromine complexes. Some differences in the magnitude of the enhancement were observed however and these effects are discussed in terms of the charge transfer theory.     

Vibrational spectra of nitrido and oxo complexes

The vibrational spectra of a number of transition-metal complexes containing terminal or bridging nitrido (N^3?) and oxo (O^2?) ligands are reported. Full assignments of fundamental modes are given for (OsO₃¹⁴N)^?, (OsO₃¹⁵N)^?, (Os¹⁴NX₄)^?, (Os¹⁵NX₄)^?, (Ru¹⁴NX₄)^?, (Os¹⁴NX₅)^2?, (Os¹⁵NX₅)^2? and (Ru¹⁴NX₅)^2? (X = Cl, Br), and also for the oxo complexes (Mo¹⁶OCl₄, (Mo¹⁸OCl₄)^?, (Mo¹⁶OCl₅)^2? and (Mo¹⁸OCl₅)^2?. Force constants have been evaluated for the four- and five-coordinate complexes. The significance of the results is discussed in terms of the metalligand bonding involved in these species.     

Vibrational spectra of complexes of norbornadiene with transition metals

Russian Chemical Bulletin -     

Vibrational spectra and structure of thiolatomercury(II) complexes

Vibrational spectra and crystallographic studies of MeSHgX (X = Cl,Br) and related thiolatomercury(II) complexes indicate that attempted assignment of structure for RSHg(II) complexes from vibrational spectra requires extreme caution.     

Vibrational spectra of zinc halide complexes with trimethylphosphine oxide

The Raman and IR spectra are reported for the complexes ZnCl₂.2TMPO, ZnBr₂.2TMPO and ZnI₂.2TMPO. The observed frequencies for polycrystalline samples are assigned on the basis of a C_3v structure for the TMPO ligand and a C_2y structure for the ZnX₂O₂ skeletal fundamentals. To discuss the coordination effects of TMPO, the ligand vibrations are compared with those of free TMPO and the skeletal vibrations with those of acetonitrile complexes. Using the ratios of G matrix elements and of observed frequencies for symmetric and asymmetric Zn-X stretching modes, the ZnX₂O₂ skeletal structures are found to be tetrahedral.     

Photoelectron spectra of electron donor—acceptor complexes between bromine and alkylamines

The photoelectron spectra of N,N-diethylmethylamine—Br₂, triethylamine—Br₂, tri-n-propylamine—Br₂ and tri-n-butylamine— Br₂ complexes were observed. The n orbitals of the alkylamines as electron donors were found to be stabilized by molecular complex formation, while the σ4p and π4p orbitals of the bromine molecule were destabilized. These results strongly support the charge-transfer mechanism for the complex formation.     

The formation of charge-transfer complexes from N-vinylindole and chlorine,bromine, and iodine

The reaction of vinylindole with bromine, chlorine, and iodine in CCl₄ solution in the cold leads to the formation of charge-transfer complexes (CTC). The formation of CTC has been confirmed by a study of the physicochemical properties and the IR and UV spectra of the reaction products.     

Vibrational spectra of AuF5 complexes with nitrogen fluorides and oxofluorides

Vibrational spectra and structural features of AuF₅ complexes with nitrogen fluorides (NF₃, N₂F₄) and oxofluorides (FNO, NF₃O) are investigated. Vibrational frequency assignment in the solid phase and in solution of anhydrous HF was made. Distinctive features of vibrational spectra of X⁺AuF₆ ^? (X = NF₄ ⁺, N₂F₃ ⁺, NO⁺, NOF₂ ⁺) related to structural transformations of cations and hexafluoroaurate anion due to the influence of the crystal field and cation-anion interactions are discussed.     

Vibrational spectra and structure of complexes containing the hydrogen dinitrate ion

Infrared and Raman spectra of solid hydrogen dinitrate complexes with K⁺, Rb⁺, Cs⁺, (CH₃)₄N⁺, trans-(Co py₄Cl₂)⁺, Ph₄As⁺, Ph₄P⁺, (C₂H₅)₄N⁺ and (C₄H₉)N⁺ have been recorded and analyzed. The assignments were assisted by deuteration and, in the case of the Cs⁺, (CH₃)₄N⁺, and Ph₄As⁺ complexes, by ¹⁵N substitution. Infrared spectra at 50 kbar of the (CH₃)₄N⁺ complex were also recorded. The salient features of the i.r. spectra are the lack of fundamental OH bands above 1800 cm⁻¹ and the appearance of a strong absorption centered at about 600 cm⁻¹, both indicating very strong hydrogen bonding. The i.r. and Raman spectra permit the differentiation between the planar and nonplanar types of the hydrogen dinitrate ion.     

Infrared spectra of new Re(III) complexes with thiourea derivatives

Complexes of the type [Re(III)L6]X3, with L = thiourea, N-methylthiourea, N-ethylthiourea or N,N'-dimethytlthiourea and X = Cl- or PF6-, were prepared as suitable precursors for the synthesis of new rhenium complexes potentially useful in nuclear medicine. The infrared (IR) spectra of these complexes were recorded and analyzed and a general vibrational pattern for Re(III) complexes with thiourea derivatives could be established. Approximate assignments for N-allylthiourea and N-ethylthiourea are also proposed for the first time. The synthesis of the new complex [Re(III)(N-allylthiourea)6](PF6)3 is also reported, and information about its structural characteristics was obtained comparing its IR spectrum with those of the other complexes of the investigated series.     

Spectrophotometric study of the reaction of iodine and bromine with two new macrocycle diamides and di-ortho methoxybenzoyl thiourea in chloroform solution

The complex formation reactions of iodine and bromine with two new macrocycle diamides (1 and 2) and di-ortho methoxybenzoyl thiourea (DOMBT) (3) have been studied spectrophotometrically at various temperatures in chloroform solution. In all cases the resulting 1:2 (macrocycle to halogen) or (DOMBT to halogen) molecular complexes were formulated as (macrocycle...X(+))X(3)(-) or (DOMBT.... X(+))X(3)(-). The formation constants of the resulting molecular complexes were evaluated from computer fitting of the absorbance-mole ratio data. For iodine complexes we found that the values of K(f) vary in the order of 1 approximately 2>3. In the case of bromine complexes the values of K(f) are larger (>10(8)) and vary in the order of 1>2>3. The enthalpy and entropy of complexation reactions of iodine with 1, 2 and 3 were determined from the temperature dependence of the formation constants. In all cases it was found that the complexation reactions are enthalpy stabilized, but entropy destabilized.     

Vibrational spectra of the Cu(II) complexes of L-asparagine and L-glutamine

The infrared and Raman spectra of the copper(II) complexes [Cu(L-asn)2] and [Cu(L-gln)2] (L-asn=L-asparagine; L-gln=L-glutamine), were recorded and analyzed in relation to its structural peculiarities. Some comparisons between the spectra of these complexes and with those of related systems are made. The characteristics of the carboxylate and amide groups of the bonded ligands are discussed in detail.