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1.
The structural change near the phase transition temperatures of [NH2(CH3)2]2CuCl4 is discussed in terms of the chemical shifts and the spin-lattice relaxation times T1ρ in the rotating frame for 1H MAS NMR and 13C CP/MAS NMR. The 1H T1ρ undergoes molecular motion near the phase-transition temperature (TC2 = 253 K). In addition, the two inequivalent [NH2(CH3)2] (1) and [NH2(CH3)2] (2) sites were distinguishable by the 13C chemical shift. And, the most significant change was observed at TC2 for the 13C CP/MAS NMR spectrum; this temperature corresponds to a ferroelastic phase transition with different orientations. 相似文献
2.
The temperature dependences of the chemical shifts and intensities of 1H, 13C, and 14N nuclei in tetramethylammonium tetrabromozincate, [N(CH3)4]2ZnBr4, were investigated using single-crystal nuclear magnetic resonance (NMR) and magic angle spinning (MAS) NMR spectroscopy to elucidate the structural geometry near the phase transition temperature. Based on the analysis of the 13C cross-polarization (CP)/MAS NMR and 14N NMR spectra, the two chemically inequivalent N(1) (CH3)4 and N(2) (CH3)4 ions were distinguished. Furthermore, the 14N NMR spectrum at the phase transition temperature indicated the existence of the ferroelastic characteristics of the N(CH3)4 ions. 相似文献
3.
The (C7H12N2)2[SnCl6]Cl2·1.5H2O complex is a new member of the family of hybrid organic–inorganic perovskite compounds. It exhibits two order–disorder phase transitions with changes in the conformation of aromatic cations at the two transition temperatures 360 and 412 K. Differential scanning calorimetry, nuclear magnetic resonance (NMR), and Fourier-transform infrared (FT-IR) spectroscopy were used to investigate these phase transitions. These transition mechanisms were investigated in terms of the spin–lattice relaxation times T1 for 1H static NMR and the chemical shifts for 13C CP–MAS. The temperature dependence of T1(1H) and 13C chemical shifts are changed near TC1 and TC2. Furthermore, the splitting for 13C NMR signals in Phases (II) and (III) indicated a ferroelastic characteristic of the compound. In addition, FT-IR results indicate that the ordered conformational structure of aromatic cations undergoes a remarkable disorder with increasing temperature. The NMR and FT-IR studies suggest that the phase transition mechanisms are related to the reorientational motion of [C7H12N2]2+ cations as a whole. Phase transition was examined in light of the interesting optical properties of this material. 相似文献
4.
Some new phosphoramidates were synthesized and characterized by 1H, 13C, 31P NMR, IR spectroscopy and elemental analysis. The structures of CF3C(O)N(H)P(O)[N(CH3)(CH2C6H5)]2 ( 1 ) and 4‐NO2‐C6H4N(H)P(O)[4‐CH3‐NC5H9]2 ( 6 ) were confirmed by X‐ray single crystal determination. Compound 1 forms a centrosymmetric dimer and compound 6 forms a polymeric zigzag chain, both via ‐N‐H…O=P‐ intermolecular hydrogen bonds. Also, weak C‐H…F and C‐H…O hydrogen bonds were observed in compounds 1 and 6 , respectively. 13C NMR spectra were used for study of 2J(P,C) and 3J(P,C) coupling constants that were showed in the molecules containing N(C2H5)2 and N(C2H5)(CH2C6H5) moieties, 2J(P,C)>3J(P,C). A contrast result was obtained for the compounds involving a five‐membered ring aliphatic amine group, NC4H8. 2J(P,C) for N(C2H5)2 moiety and in NC4H8 are nearly the same, but 3J(P, C) values are larger than those in molecules with a pyrrolidinyl ring. This comparison was done for compounds with six and seven‐membered ring amine groups. In compounds with formula XP(O)[N(CH2R)(CH2C6H5)]2, 2J(P,CH2)benzylic>2J(P,CH2)aliphatic, in an agreement with our previous study. 相似文献
5.
New hydrocarbon bridged co-condensation agents of the type RSi(OMe)2(CH2)zC6H4(CH2)z(OMe)2SiR { 3[Ph(1,4-C3D0)2] , z = 3, R = Me; 3[Ph(1,4-C3T0)2] , z = 3, R = OMe; 4[Ph(1,4-C3D0)2] , z = 4, R = Me} were synthesized by hydrosilylation of the corresponding α,ω-dienes CH2=CH–(CH2)z–2–C6H4–(CH2)z–2–CH=CH2 [z = 3 ( 1 ), 4 ( 2 )] with HSiR(OMe)2 (R = Me, OMe). These silane monomers were sol-gel processed, partially with MeSi(OMe)3 ( T 0) to give the polysiloxanes 3 a , 3 b , 4 c , 3 d , 3 e , 4 f , and 3 ab (Table 1, Schemes 2 and 3); D = D type silicon atom (two oxygen neighbors), T = T type of silicon atom (three oxygen neighbors). The relative amounts of T and D silyl species and the degrees of condensation were determined by 29Si and 13C CP/MAS NMR spectroscopic investigations. 29Si and 13C CP/MAS NMR relaxation time studies (TSiH, TCH, T1ρH), and 2 D WISE NMR experiments were applied to get knowledge about the polymer dynamics. For the first time protons of such polysiloxane systems were detected by 1H SPE/MAS NMR measurements in suspension. Mobility studies were carried out in different solvents. Furthermore the swelling capacities of the polymers 3 a , 3 b , and 4 c in different solvents and the BET surface areas of all materials were investigated. SEM micrographs show the morphology of 3 a and 3 b . 相似文献
6.
Some new N‐4‐Fluorobenzoyl phosphoric triamides with formula 4‐F‐C6H4C(O)N(H)P(O)X2, X = NH‐C(CH3)3 ( 1 ), NH‐CH2‐CH=CH2 ( 2 ), NH‐CH2C6H5 ( 3 ), N(CH3)(C6H5) ( 4 ), NH‐CH(CH3)(C6H5) ( 5 ) were synthesized and characterized by 1H, 13C, 31P NMR, IR and Mass spectroscopy and elemental analysis. The structures of compounds 1 , 3 and 4 were investigated by X‐ray crystallography. The P=O and C=O bonds in these compounds are anti. Compounds 1 and 3 form one dimensional polymeric chain produced by intra‐ and intermolecular ‐P=O···H‐N‐ hydrogen bonds. Compound 4 forms only a centrosymmetric dimer in the crystalline lattice via two equal ‐P=O···H‐N‐ hydrogen bonds. 1H and 13C NMR spectra show two series of signals for the two amine groups in compound 1 . This is also observed for the two α‐methylbenzylamine groups in 5 due to the presence of chiral carbon atom in molecule. 13C NMR spectrum of compound 4 shows that 2J(P,Caliphatic) coupling constant for CH2 group is greater than for CH3 in agreement with our previous study. Mass spectra of compounds 1 ‐ 3 (containing 4‐F‐C6H4C(O)N(H)P(O) moiety) indicate the fragments of amidophosphoric acid and 4‐F‐C6H4CN+ that formed in a pseudo McLafferty rearrangement pathway. Also, the fragments of aliphatic amines have high intensity in mass spectra. 相似文献
7.
《Journal of Saudi Chemical Society》2020,24(8):567-583
The two new hybrids single crystals having the general formula [(CH3CH2CH2)4N]2MIICl4 with MII = Co (1) and Mn (2) have been synthetised by the slow evaporation process in aqueous solutions. In this article, these compounds were described by the following characterization techniques: X-rays diffraction, thermal analysis (TGA-TDA), vibrational spectroscopy, nuclear magnetic resonance (NMR), and electrical properties. From the crystallographic study, the crystals (1) and (2) have been disclosed to be crystallized too in the centrosymmetric monoclinic systems, with space group P21/c (Z = 4) and C2/c (Z = 8), respectively. Their crystal structures consist of [MCl4]2− anions and two different cations [(CH3CH2CH2)4N]+, which are connected by a three dimensional network of C-H···Cl hydrogen bonds. In both crystals, each MII center atom being surrounded by four chloride ligands forming a slightly distorted tetrahedral geometry. The tetrahedral [CoCl4]2− is ordered, while the tetrahedral [MnCl4]2− is disordered. Some tetrapropylammonium cations of these compounds are found to be disordered. The thermal analysis studies made in the temperature range (298–473 K) did not show any phase transition for the two crystals. Furthermore, the electrical properties of the two compounds are studied by using the complex impedance spectroscopy technique in the temperature and frequency field varied of 290–363 K and 1 kHz–13 MHz, respectively. 相似文献
8.
Experimental Investigation on Binary Phase Diagram of the Thermotropic Phase Transitions Compounds (n‐CnH2n+1R3)2ZnCl4
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The thermotropic phase transitions compounds (n‐CnH2n+1R3)2ZnCl4 as well as a series of their binary mixtures were prepared by a solution reflux method from their ethanol solutions. The experimental subsolidus binary phase diagram of [n‐C18H37N(CH3)3]2ZnCl4‐[n‐(C18H37)2N(CH3)2]2ZnCl4 is constructed over the entire composition range by differential scanning calorimetry(DSC) and X‐ray. Experi‐ mental results indicate one stable intermediate phase [n‐C18H37N(CH3)3] [n‐(C18H37)2N(CH3)2]ZnCl4 at WC18C3Zn %=59.75 %, and two invariant three phase equilibria, which shows two eutectoid temperatures: Te1 at 310±1 K for eutectoid point WC18C3Zn %=36.24 %, Te2 at 313±1 K for eutectoid point WC18C3Zn %=80.17 %. These three noticeable solid‐solution ranges are α‐phase at the left, ?‐phase at the right, and ψ‐phase in the middle of the phase diagram. It is (n‐CnH2n+1R3)2ZnCl4 systems as phase change materials that are characterized the phase transition temperatures T in the range of 310 to 340 K, the transition enthalpies ΔH in the range of 38.40 and 168.72 J/g between two polymorphic forms. 相似文献
9.
Synthesis and Molecular Structure of the Binuclear tert-Butyliminovanadium(IV) Complexes [(μ-NtC4H9)2V2(CH2CMe3)2X2] (X = OtC4H9, CH2CMe3) Syntheses of the neopentylvanadium(V) compounds tC4H9N?V(CH2CMe3)3?n(OtC4H9)n (n = 0 ( 7 ), 1 ( 6 ), 2) are described. 6 and 7 decompose by irradiation splitting off neopentane and yielding the binuclear diamagnetic neopentylvanadium(IV) complexes [(μ-NtC4H9)2V2(CH2CMe3)2X2] [X = OtC4H9 ( 8 ), CH2CMe3 ( 11 )]. All compounds obtained are characterized by 1H and 51V NMR spectroscopy. 8 has been found by X-ray diffraction analysis to be a binuclear complex with bridging tert-butylimino ligands and a vanadium—vanadium single bond. The complexes tC4H9N?V(CH2C6H5)(OtC4H9)2 and [(μ-NtC4H9)2V2(CH2SiMe3)2(OtC4H9)2] ( 10 ) have been also prepared; the crystal structure of 8 and 10 are nearly identical. 相似文献
10.
Tushar S. Basu Baul Anup Paul Anthony Linden 《Journal of organometallic chemistry》2012,696(26):4229-4235
Three triorganotin(IV) complexes of composition R3SnLH (R = Me, Bu and Ph and LH = 2-[(E)-2-(4-hydroxy-3,5-dimethylphenyl)-1-diazenyl]benzoate) have been synthesized and characterized by 1H, 13C, 119Sn NMR, and IR spectroscopic techniques in combination with elemental analysis. The crystal structures of the carboxylate ligand HO2CC6H4{NN(C6H2-4-OH-3,5-(CH3)2)}-o in its neutral form and three triorganotin(IV) complexes, viz., polymeric (R3Sn[O2CC6H4{N–N(H)(C6H2-4-O-3,5-(CH3)2)}-o])n (R = Me (1) and Bu (2)) and monomeric Ph3Sn[O2CC6H4{N–N(H)(C6H2-4-O-3,5-(CH3)2)}-o] (3) complexes are reported. The polymeric complexes 1 and 2 exist as extended chains in which the LH-bridged Sn-atoms adopt a trans-R3SnO2 trigonal bipyramidal configuration with R groups in the equatorial positions and the axial sites occupied by an oxygen atom from the carboxylate ligand and the phenoxide O atom of the next carboxylate ligand. The Sn atom in complex 3 has a distorted tetrahedral geometry. In all three complexes, the carboxylate ligand is in the zwitterionic form with the phenolic proton moved to the nearby azo nitrogen atom, in contrast to the free carboxylic acid ligand which is in the azo form. 相似文献
11.
《Journal of organometallic chemistry》2011,696(26):4229-4235
Three triorganotin(IV) complexes of composition R3SnLH (R = Me, Bu and Ph and LH = 2-[(E)-2-(4-hydroxy-3,5-dimethylphenyl)-1-diazenyl]benzoate) have been synthesized and characterized by 1H, 13C, 119Sn NMR, and IR spectroscopic techniques in combination with elemental analysis. The crystal structures of the carboxylate ligand HO2CC6H4{NN(C6H2-4-OH-3,5-(CH3)2)}-o in its neutral form and three triorganotin(IV) complexes, viz., polymeric (R3Sn[O2CC6H4{N–N(H)(C6H2-4-O-3,5-(CH3)2)}-o])n (R = Me (1) and Bu (2)) and monomeric Ph3Sn[O2CC6H4{N–N(H)(C6H2-4-O-3,5-(CH3)2)}-o] (3) complexes are reported. The polymeric complexes 1 and 2 exist as extended chains in which the LH-bridged Sn-atoms adopt a trans-R3SnO2 trigonal bipyramidal configuration with R groups in the equatorial positions and the axial sites occupied by an oxygen atom from the carboxylate ligand and the phenoxide O atom of the next carboxylate ligand. The Sn atom in complex 3 has a distorted tetrahedral geometry. In all three complexes, the carboxylate ligand is in the zwitterionic form with the phenolic proton moved to the nearby azo nitrogen atom, in contrast to the free carboxylic acid ligand which is in the azo form. 相似文献
12.
Xerogels containing residues of amide derivatives of phosphonic and thiophosphonic acids, ≡Si(CH2)3NHP(S, O)(OC2H5)2 (functional group concentration of 1.3–2.2 mmol/g) have been prepared by a sol-gel method. It has been shown that xerogels having a developed porous structure (with specific surface areas of 240–485 m2/g, pore volumes of 0.20–0.50 cm3/g, and pore diameters of 3.6–6.5 nm) are formed at tetraethoxysilane-to-trifunctional silane ratios of 4: 1 (and above) and 6: 1 (and above) for the derivatives of phosphonic and thiophosphonic acids, respectively. The IR and 13C CP/MAS NMR spectroscopy data have demonstrated that the surface layer of the xerogels contains not only (thio)phosphonic acid residues, but also silanol groups and water molecules participating in hydrogen bonding. The 29Si CP/MAS NMR spectroscopy data have indicated that structural groups are, for the most part, contained in structural units T3 [(≡SiO)3Si(CH2)3NHP(O, S)(OC2H5)2] and T2 [(≡SiO)2Si(OR)[(CH2)3NHP(O, S)(OC2H5)2] (R = H or C2H5). 相似文献
13.
An organic–inorganic hybrid compound [(CH3)2NH2]2ZnBr4 has been prepared at room temperature under the slow evaporation method. Its structure was solved at 150 K using the single-crystal X-ray diffraction method. [(CH3)2NH2]2ZnBr4 crystallizes in the monoclinic system – a = 8.5512 (12) Å, b = 11.825 (2) Å, c = 13.499 (2) Å, β = 90.358 (6)°, V = 1365 (4) Å3, and Z = 4, space group P21/n. In the structure of [(CH3)2NH2]2ZnBr4, tetrabromozincate anions are connected to organic cations through N–H⋯ Br hydrogen bonds. Differential scanning calorimetry (DSC) measurements indicate that [(CH3)2NH2]2ZnBr4 undergoes four phase transitions at T1 = 281 K, T2 = 340 K, T3 = 377 K, and T4 = 408 K. Meanwhile, several studies including DSC measurements and variable-temperature structural analyses were performed to reveal the structural phase transition at T = 281 K in [(CH3)2NH2]2ZnBr4. Conductivity and dielectric study as a function of temperature (378 < T [K] < 423) and frequency (10−1 < f [Hz] < 106) were investigated. Analysis of equivalent circuit, alternating current conductivity, and dielectric studies confirmed the phase transition at T4. Conduction takes place by correlated barrier hopping in each phase. 相似文献
14.
Alpar Pöllnitz Vito Lippolis Massimiliano Arca Anca Silvestru 《Journal of organometallic chemistry》2011,696(15-16):2837-2844
Cleavage of the Se–Se bond in [2-(Et2NCH2)C6H4]2Se2 (1) with SO2Cl2 (1:1 molar ratio) yielded the organoselenium(II) chloride [2-(Et2NCH2)C6H4]SeCl (2). Treatment of 2 with excess of KX yielded the organoselenium(II) halides [2-(Et2NCH2)C6H4]SeX [X = Br (3), I (4)]. The new compounds 2–4 were characterized by solution NMR spectroscopy (1H, 13C, 77Se, 2D experiments). The solid-state molecular structures of 2, 2·HCl and 3 were established by single crystal X-ray diffraction. Distorted T-shaped coordination geometries of type (C,N)SeX (X = Cl, Br) and CSeCl2 were found for the neutral halides 2 and 3, and the zwitterionic species [2-{Et2N+(H)CH2}C6H4]SeCl2 ̄ (2·HCl), respectively. DFT calculations were performed on 2–4 and the related tellurium compounds [2-(Et2NCH2)C6H4]TeX [X = Cl (5), Br (6) and I (7)] in order to elucidate the bond nature and FT-Raman features of this class of organochalcogen(II) derivatives. 相似文献
15.
Archana Chaudhary Namita Sharma Veena Dhayal Arpita Saxena Meena Nagar Rakesh Bohra 《应用有机金属化学》2011,25(3):198-206
Some bis(cyclopentadienyl)titanium(IV) complexes of the type [Cp2TiCl2?n{L}n] {where, n = 1 or 2; L = ONC(R)Ar; R = H or CH3 and Ar = C5H4N‐2, C4H3O‐2 or C4H3S‐2} have been synthesized by the metathetical reactions of Cp2TiCl2 with the sodium salt of internally functionalized oximes in 1:1 and 1:2 stoichiometry in anhydrous THF. All these red to brown colored solid derivatives have been characterized by elemental analyses, FT‐IR and NMR (1H and 13C{1H}) spectral studies. The FAB mass spectra of some representative derivatives indicate their monomeric nature. Oximato ligands in all the complexes appear to bind the titanium via N and O in a dihapto ( ‐N, O) manner in the solid state. Thermogravimetric curves of [Cp2TiCl{ONC(CH3)C5H4N‐2}] and [Cp2Ti{ONC(CH3)C5H4N‐2}2] suggest the formation of hybrid materials CpTiO(Cl) and Cp2TiO, respectively, as the final products at 900 °C under nitrogen atmosphere. Sol–gel transformations of Cp2TiCl2, [Cp2TiCl{ONC(CH3)C5H4N‐2}] and [Cp2Ti{ONC(CH3)C5H4N‐2}2] yielded titania a–c, respectively, at low sintering temperature (600 °C). The powder XRD patterns, IR as well as Raman spectra of all these oxides indicate the formation of nano‐sized anatase phase. The SEM images of titania a–c indicate agglomers like surface morphologies. The absorption spectra of a–c exhibit an energy band gap in the range of 3.47–3.71 eV. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
16.
Complete demethylation of Cp2Ti(CH3)2 in dichloromethane with 2 M equivalent of [η5-(C5H4COOH)]Cr(CO)2NO (5), [η5-(C5H4COOH)]Cr(NO)2X] (X = Cl 6, X = I 7), and [η5-(C5H4COOH)]W(CO)3CH3 (8); gives Cp2Ti{[OC(O)C5H4]Cr(CO)2NO}2 (13), Cp2Ti{[OC(O)C5H4]Cr(NO)2Cl}2 (14), Cp2Ti{[OC(O)C5H4]Cr(NO)2I}2 (15),and Cp2Ti{[OC(O)C5H4]W(CO)3CH3}2 (16), respectively. The chemical shifts of C(2)-C(5) carbon atoms of compounds 13-15 have been assigned using two-dimensional HetCOR NMR spectroscopy. The assigned chemical shifts were compared with the NMR data of their analogues of ferrocene, and the opposite correlation on the assignments was observed for cynichrodenoyl moieties. 相似文献
17.
A. V. Ivanov A. S. Zaeva E. V. Novikova A. V. Gerasimenko W. Forsling 《Russian Journal of Coordination Chemistry》2007,33(4):233-243
Crystalline adducts of zinc and copper(II) dithiocarbamate complexes with dibutyl-and diisobutylamines of the general formula [M(NHR′2)(S2CNR2)2] (M = Zn, 63Cu, and 65Cu; R = CH3 and C2H5; R2 = (CH2)4O; R′ = C4H9 and i-C4H9) were synthesized. Their structures and spectroscopic properties were studied by EPR and solid-state natural abundance 13C and 15N CP/MAS NMR spectroscopy. Experimental EPR data and computer-assisted modeling confirmed the individual character of copper(II) adducts. The geometries of the copper coordination polyhedra were found to be intermediate between a tetragonal pyramid and a trigonal bipyramid (TBP). The contributions from TBP to the geometries of the adducts obtained were calculated from the EPR data. According to the X-ray diffraction data, the adduct of zinc diethyldithiocarbamate with diisobutylamine exists in two isomeric forms. The 13C and 15N CP/MAS NMR signals were assigned to the atomic positions in two crystallographically independent conformer molecules. 相似文献
18.
Jiří Pinkas Róbert Gyepes Jiří Kubišta Michal Horáček Martin Lamač 《Journal of organometallic chemistry》2011,696(11-12):2364-2372
The preparation of a new functionalized cyclopentadienyl ligand bearing a nitrile pendant substituent, (C5H4CMe2CH2CN)? is reported. The corresponding lithium salt of this ligand (1) was prepared by the reaction of in situ lithiated acetonitrile with 6,6-dimethylfulvene. The ligand was subsequently utilized for the synthesis of group 4 metal complexes [(η5–C5H4CMe2CH2CN)2MCl2] (M = Ti, 2; M = Zr, 3; M = Hf, 4), [(η5–C5H5) (η5–C5H4CMe2CH2CN)MCl2] (M = Ti, 7; M = Zr, 8), and [(η5-C5Me5) (η5 C5H4CMe2CH2CN)2ZrCl2] (9). Alternative route to 2 comprised the preparation of half-sandwich complex [(η5–C5H4CMe2CH2CN)TiCl3] (6). The prepared compounds were characterized by common spectroscopic methods and the solid state structures of complexes 2, 3, 4, 7, and 9 were determined by the single-crystal X-ray diffraction analysis. In addition, compound 7 was converted to the corresponding dimethyl derivative [(η5–C5H5) (η5–C5H4CMe2CH2CN)TiMe2] (10) and also treated with the chloride anion abstractor Li[B(C6F5)4] to generate the cationic complex with the coordinated nitrile group, as suggested by the NMR spectroscopy. A formation of yet another cationic complex was observed upon treating compound 10 with (Ph3C)[B(C6F5)4]. 相似文献
19.
Xu-Feng Liu 《Journal of Coordination Chemistry》2017,70(1):116-126
Four diiron dithiolate complexes with monophosphine ligands have been prepared and structurally characterized. Reactions of (μ-SCH2CH2S-μ)Fe2(CO)6 or [μ-SCH(CH3)CH(CH3)S-μ]Fe2(CO)6 with tris(4-chlorophenyl)phosphine or diphenyl-2-pyridylphosphine in the presence of Me3NO·2H2O afforded diiron pentacarbonyl complexes with monophosphine ligands (μ-SCH2CH2S-μ)Fe2(CO)5[P(4-C6H4Cl)3] (1), (μ-SCH2CH2S-μ)Fe2(CO)5[Ph2P(2-C5H4N)] (2), [μ-SCH(CH3)CH(CH3)S-μ]Fe2(CO)5[P(4-C6H4Cl)3] (3), and [μ-SCH(CH3)CH(CH3)S-μ]Fe2(CO)5[Ph2P(2-C5H4N)] (4) in good yields. Complexes 1–4 were characterized by elemental analysis, 1H NMR, 31P{1H} NMR and 13C{1H} NMR spectroscopy. Furthermore, the molecular structures of 1–4 were confirmed by X-ray crystallography. 相似文献
20.
Two solid phase transitions of [Cd(H2O)6](BF4)2 occurring on heating at TC2=183.3 K and TC1=325.3 K, with 2 K and 5 K hysteresis, respectively, were detected by differential scanning calorimetry (DSC). High value of entropy changes indicated large orientational disorder of the high temperature and intermediate phase. Nuclear magnetic resonance (1H NMR and 19F NMR) relaxation measurements revealed that the phase transitions at TC1 and TC2 were associated with a drastic and small change, respectively, of the both spin-lattice relaxation times: T1(1H) and T1(19F). These relaxation processes were connected with the “tumbling” motions of the [Cd(H2O)6]2+, reorientational motions of the H2O ligands, and with the iso- and anisotropic reorientation of the BF4− anions. The cross-relaxation effect was observed in phase III. The line width and the second moment of the 1H and 19F NMR line measurements revealed that the H2O reorientate in all three phases of the title compound. On heating the onset of the reorientation of 3 H2O in the [Cd(H2O)6]+2, around the three-fold symmetry axis of these octahedron, causes the isotropic reorientation of the whole cation. The BF4− reorientate isotropically in the phases I and II, but in the phase III they perform slow reorientation only about three- or two-fold axes. A small distortion in the structure of BF4− as well as of [Cd(H2O)6]2+ is postulated. The temperature dependence of the bandwidth of the O-H stretching mode measured by Fourier transform middle infrared spectroscopy (FT-MIR) indicated that the activation energy for the reorientation of the H2O did not change much at the TC2 phase transition. 相似文献