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1.
Nina I. Giricheva Georgiy V. Girichev Yulia S. Medvedeva Sergey N. Ivanov Vyacheslav M. Petrov 《Structural chemistry》2012,23(3):895-903
A combined gas-phase electron diffraction and quantum chemical (B3LYP/cc-pVTZ, MP2/cc-pVDZ) study of molecular structure of
2,4,6-trinitrobenzenesulfonic acid (2,4,6-tri-NBSA) was carried out. Quantum chemical calculations showed that 2,4,6-tri-NBSA
possesses six conformers, which form three pairs of enantiomers with the relative energy of 0, 4.4/3.9, and 2.5/2.5 kcal/mol.
It was experimentally established that at T = 444(5) K a saturated vapor over 2,4,6-tri-NBSA is, predominantly (up to 93 mol.%), represented by a low-energy enantiomers
II and II′ characterized by intramolecular hydrogen bond between an H atom of the hydroxyl group and one of the O atoms of
the NO2 group. Experimental internuclear distances for the low-energy enantiomers are (?): r
h1(C–C)av. = 1.387(4), r
h1(C–S) = 1.811(6), r
h1(S=O)av. = 1.424(4), r
h1(S–O) = 1.579(4), r
h1(N–O)av. = 1.214(3), r
h1(C–N)av. = 1.491(5). Geometry of the conformer II points on existance of strong steric interactions between SO2OH group and two ortho-nitro groups. Analysis of the orbital interactions between the substituents and benzene ring was carried out. Geometric parameters
and energies of transition states between conformers were calculated (B3LYP). 相似文献
2.
The conformational composition of gaseous MTMNB and the molecular structures of the rotational forms have been studied by
electron diffraction at 130∘C aided by results from ab initio and density functional theory calculations. The conformational potential energy surface
has been investigated by using the B3LYP/6-31G(d,p) method. As a result, six minimum-energy conformers have been identified.
Geometries of all conformers were optimized using MP2/6-31G(d,p), B3LYP/6-31G(d,p), and B3LYP/cc-pVTZ methods. These calculations
resulted in accurate geometries, relative energies, and harmonic vibrational frequencies for all conformers. The B3LYP/cc-pVTZ
energies were then used to calculate the Boltzmann distribution of conformers. The best fit of the electron diffraction data
to calculated values was obtained for the six conformer model, in agreement with the theoretical predictions. Average parameter
values (ra in angstroms, angle α in degrees, and estimated total errors given in parentheses) weighted for the mixture of six conformers
are r(C–C) = 1.507(5), r(C–C)ring, av = 1.397(3), r(C–S)av = 1.814(4), r(C–N) = 1.495(4), r(N–O)av = 1.223(3), ∠(C–C–C)ring = 116.0–122.5, ∠ C6–C4–C7 = 118.2(4), ∠ C–C–S = 113.6(6), ∠ C–S–C = 98.5(12), ∠ N–C–C4 = 121.9(3), ∠(O–N–C)av = 116.8(3), ∠ O–N–O = 127.0(4). Torsional angles could not be refined. Theoretical B3LYP/cc-pVTZ torsional angles for the
rotation about C–N bond, φC−N, were found to be 30.5–36.5∘ for different conformers. As to internal rotation about C–C and C–S bonds, values of φC−C = 68–118∘ and φC−S = 66–71∘ were obtained for the three most stable conformers with gauche orientation with respect to these bonds.
Some conclusions of this work were presented in a short communication in Russ. J. Phys. Chem. 2005, 79, 1701. 相似文献
3.
K. Ramalingam R. Thiruneelakandan G. Bocelli L. Righi 《Transition Metal Chemistry》2012,37(3):265-270
The complexes trans-[Ni(4-MP)2(NCS)2]·MeCN (1) and trans-[Ni(3-MP)2(NCS)2] (2) (4-MP = tri(4-methylphenyl)phosphine, 3-MP = tri(3-methylphenyl)phosphine) were prepared and characterized by IR, UV–visible,
NMR spectra, CV, TGA and single crystal X-ray crystallography. Both the complexes have planar geometry and are diamagnetic.
The Ni–P distances in both complexes are relatively short as a result of strong back donation from nickel to phosphorus. The
phenyl rings in the 3-MP analogue (2) show increased pitching with reference to the plane formed by the ipso carbons due to increased steric effects. For complex
(2), the N–Ni–N and P–Ni–P angles are significantly lower than the almost linear N–Ni–N and N–Ni–P angles observed for both
complex (1) and trans-[Ni(PPh3)2(NCS)2]. This observation indicates that the 3-methylphosphine ligand forces complex (2) to distort towards a tetrahedral geometry. IR spectra of both complexes show strong bands around 2,090 cm−1 due to N-coordinated thiocyanate, while the electronic spectra contain d–d transitions around 452 nm. Cyclic voltammograms
show that the irreversible one-electron reduction potentials increase in the following order: trans- [Ni(PPh3)2(NCS)2] < trans- [Ni(3-MP)2(NCS)2] < trans-[Ni(4-MP)2(NCS)2], revealing the electron releasing effect of the methyl groups. The planar complexes exhibit interallogony in coordinating
solvents. 相似文献
4.
Anna Rita Campanelli Aldo Domenicano Fabio Ramondo István Hargittai 《Structural chemistry》2011,22(2):361-369
The molecular structure of triphenylsilane has been investigated by gas-phase electron diffraction and theoretical calculations.
The electron diffraction intensities from a previous study (Rozsondai B, Hargittai I, J Organomet Chem 334:269, 1987) have
been reanalyzed using geometrical constraints and initial values of vibrational amplitudes from calculations. The free molecule
has a chiral, propeller-like equilibrium conformation of C
3 symmetry, with a twist angle of the phenyl groups τ = 39° ± 3°; the two enantiomeric conformers easily interconvert via three
possible pathways. The low-frequency vibrational modes indicate that the three phenyl groups undergo large-amplitude torsional
and out-of-plane bending vibrations about their respective Si–C bonds. Least-squares refinement of a model accounting for
the bending vibrations gives the following bond distances and angles with estimated total errors: r
g(Si–C) = 1.874 ± 0.004 ?, 〈r
g(C–C)〉 = 1.402 ± 0.003 ?, 〈r
g(C–H)〉 = 1.102 ± 0.003 ?, and ∠aC–Si–H = 108.6° ± 0.4°. Electron diffraction studies and MO calculations show that the lengths of the Si–C bonds in H4−n
SiPh
n
molecules (n = 1–4) increase gradually with n, due to π → σ*(Si–C) delocalization. They also show that the mean lengths of the ring C–C bonds are about 0.003 ? larger
than in unsubstituted benzene, due to a one hundredth angstrom lengthening of the Cipso–Cortho bonds caused by silicon substitution. A small increase of r(Si–H) and decrease of the ipso angle with increasing number of phenyl groups is also revealed by the calculations. 相似文献
5.
Khodayar Gholivand Farzaneh Afshar Zahra Shariatinia Karim Zare 《Structural chemistry》2010,21(3):629-636
Abstract
New phosphoramidates with formula 3-NC5H4C(O)NHP(O)XY (X=Y=Cl (1), X=Y=NH–C(CH3)3 (2a,2b), X=Y=N(C4H9)2 (3), X=Cl, Y=N(C2H5)2 (4) were synthesized and characterized by IR, 1H-, 13C-, 31P-NMR spectroscopy and CHN elemental analysis. Surprisingly, the reaction of compound 2a with LaCl3, 7H2O in 3:1 M ratio leads to a polymorph of this compound (2b). NMR spectra indicate that 2 J(PNHamide) in 2b (7.0 Hz) is very much greater than in 2a (4.1 Hz), while δ(31P) values are identical for both of them. In IR spectra, υ(P=O) is weaker but υ(C=O) is stronger in 2a than in 2b. The structures of 2a, 2b were determined by X-ray crystallography. These compounds form centrosymmetric dimers via two intermolecular P=O……H–N hydrogen bonds. Strong intermolecular N–H…N, N–H…O and weak C–H…O hydrogen bonds lead to a three-dimensional polymeric cluster in the 2a while intermolecular strong N–H……N and weak C–H……O hydrogen bonds form a two-dimensional polymeric chain in 2b. 相似文献6.
Issa Yavari Nasir Iravani S. Zahra Sayyed-Alangi Rahimeh Hajinasiri 《Monatshefte für Chemie / Chemical Monthly》2009,35(1):1199-1204
Abstract
An efficient synthesis of alkyl acylcarbamodithioates by reaction of acid chlorides with ammonium thiocyanate in the presence of thiols is described. The unusually large values of 5 J FH = 12–15 Hz, observed for alkyl (2-fluorobenzoyl)carbamodithioates provide information about Ar–C–N–H torsion in these compounds. 相似文献7.
Aliakbar Dehno Khalaji Smail Triki Debasis Das 《Journal of Thermal Analysis and Calorimetry》2011,103(3):779-783
New 1D-chain copper(I) complex [Cu2(μ-(3,4,5-MeO-ba)2bn)(μ-I)2]
n
(1), where (3,4,5-MeO-ba)2bn = N,N′-bis(3,4-dimethoxybenzylidene)-butane-1,4-diamine, involving a new bidentate Schiff-base containing a flexible spacer (=N–C–C–C–C–N=)
has been synthesized and characterized by elemental analyses (CHN) and FT-IR spectroscopy. The crystal structure of 1 was determined from single-crystal X-ray diffraction analyses and shows the (3,4,5-MeO-ba)2en acts as a bridging ligand with the nitrogen atoms of the two imine functions and leading to the dinuclear [Cu2((μ-(3,4,5-MeO-ba)2en)] groups. Such dinuclear [Cu2((μ-(3,4,5-MeO-ba)2en)] groups are bridged by two iodine anions [(μ-I)2] to form a neutral 1D-chain copper(I) iodide coordination polymer. The coordination polyhedron about the copper(I) center
in 1 is best described as a distorted trigonal planar. Thermogravimetric analyses reveal the thermal stability and decomposition
pattern of 1. 相似文献
8.
Zuzana Vasková Zdenka Padělková Milan Mazur Dušan Valigura Jan Moncol 《Transition Metal Chemistry》2011,36(8):883-889
The synthesis, spectral characterization and crystal structures of two nitrobenzoatocopper(II) complexes, namely [Cu(2-O2Nbz)2(pca)2(H2O)2] (1) and [Cu(3,5-(O2N)2bz)2(pca)2(H2O)2] (2) (where 2-O2Nbz = 2-nitrobenzoate, 3,5-(O2N)2bz = 3,5-dinitrobenzoate, pca = pyrazinecarboxamide), are reported. Complexes 1 and 2 consist of centrosymmetric molecules with the Cu(II) atom monodentately coordinated by a pair of anionic 2-nitrobenzoato
(1) or 3,5-dinitrobenzoato (2) ligands and a pair of pyrazinecarboxamide ligands, forming a nearly tetragonal basal plane, and by a pair of water ligands
that complete the tetragonal–bipyramidal coordination polyhedron. The molecules of both complexes are linked by N–H⋯O and
O–H⋯O hydrogen bonds and lie in planes, which have different orientations depending on the space group. Similar experiments
with 3-nitrobenzoic acid resulted in the isolation of the hydrolysis product [Cu(pyzCOO)2]
n
(3) (pyzCOO = pyrazinecarboxylate). The known crystal structure of complex 3 has been re-determined at low temperature with significantly higher precision. The crystal packing and C–H⋯O/C–H⋯N hydrogen
bonds are discussed. 相似文献
9.
A. López-Hernández K. Venkatesan H. W. Schmalle Heinz Berke 《Monatshefte für Chemie / Chemical Monthly》2009,36(10):845-857
Abstract
Stable paramagnetic Cr(II) and Cr(III) bis(alkynyl) complexes of the type [trans(RC≡C)2Cr(dmpe)2] n+ (R = Ph, SiMe3, SiEt3, C≡C–SiMe3 n = 0, 1) were prepared and characterised by NMR, cyclic voltammetry, EPR, magnetic measurements, and X-ray single-crystal diffraction studies. 相似文献10.
Valiollah Mirkhani Reza Kia Akbar Rostami Vartooni Dalibor Milic 《Transition Metal Chemistry》2009,34(2):225-230
fac-[Re(CO)3(2-nben)Cl] and fac-[Re(CO)3(4-nbzen)Cl] complexes consisting of 2-nbzen = N,N′-bis(2-nitrobenzaldehyde)-1,2-diiminoethane and 4-nbzen = N,N′-bis(4-nitrobenzaldehyde)-1,2-diiminoethane were synthesized by the reaction of Re(CO)5Cl with nbzen ligands. These complexes were characterized by physico-chemical, spectroscopic methods and X-ray crystallography.
The electrochemical behavior of the two complexes was investigated by cyclic voltammetry. In the crystal structure of [Re(CO)3(4-nbzen)Cl], the neighbouring molecules are linked together by intermolecular C–H···Cl interactions to form 1D extended chains
along the b-axis.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
11.
Ming-Li Liu Jian-Min Dou Da-Cheng Li Da-Qi Wang Jian-Zhong Cui 《Transition Metal Chemistry》2012,37(1):117-124
The thiosemicarbazide and hydrazide Cu(II) complexes, [Cu3L21(py)4Cl2] (1), [Cu(HL2)py] (2) and [Cu(HL3)py] (3), (H2L1 = 1-picolinoylthiosemicarbazide, H3L2 = N′-(2-hydroxybenzylidene)-3-hydroxy-2-naphthohydrazide, H3L3 = 2-hydroxy-N′-((2-hydroxy-naphthalen-1-yl)methylene)benzohydrazide) have been prepared and characterized through physicochemical and spectroscopic
methods as well as X-ray crystallography. Complex 1 has a centrosymmetric structure with –N–N– bridged Cu3 skeleton. Neighboring molecules are linked into a 3D supermolecular framework by π–π stacking interactions, N–H···Cl and
C–H···Cl hydrogen bonds. Complexes 2 and 3 have similar planar structures but different dimers formed by concomitant Cu···N and Cu···O interactions, respectively. Solvent
accessible voids with a volume of 391 ?3 are included in the structure of complex 2, indicating that this complex is a potential host candidate. Thermogravimetric analysis shows that the three complexes are
stable up to 100 °C. 相似文献
12.
Limin Han Guangbin Zhang Ning Zhu Ruijun Xie Quanling Suo Meihua Luo Linhong Weng 《Journal of Cluster Science》2010,21(4):789-801
Two novel bimetallic complexes, [Cr(CO)3(η
6-C6H5)–C≡C–C6H4–Fc] (Fc = C5H5FeC5H4] (1) and [Cr(CO)3(η
6-C6H5)–C ≡ C–Fc–C(CH3)2–Fc] (3), were synthesized by the Sonogashira coupling reaction. By using of (1) and (3) as ligands to react with Co2(CO)8, two others novel polymetallic complexes, [Cr(CO)3(η
6-C6H5){Co2(CO)6-η
2-μ
2-C≡C–}–C6H4–Fc] (2) and [Cr(CO)3(η
6-C6H5){Co2(CO)6-η
2-μ
2-C≡C–}Fc–C(CH3)2–Fc] (4) were obtained. Four carbonyl complexes were characterized by elemental analysis, FT-IR, NMR and MS. The molecular structures
of complexes (1), (2) and (4) were determined by single crystal X-ray diffraction. The interactions among the ferrocenyl,
Cr(CO)3 and Co2(CO)6-η
2-μ
2-C≡C– units were investigated by cyclic voltammetry. 相似文献
13.
Jian-Long Xia Wei-Cheng Xiong Gang Chen Guang-Ao Yu Shan Jin Sheng-Hua Liu 《Transition Metal Chemistry》2009,34(4):389-393
Abstract Formal [2 + 2 + 2] addition reaction of [Cp*Ru(H2O)(NBD)][BF4] (NBD = norbornadiene) with 4,4′-Diethynylbiphenyl generates [C9H9-η6-C6H4(RuCp*)–C6H4(RuCp*)-η6-C9H9][BF4]2. The reaction of [Cp*Ru(H2O)(NBD)][BF4] with 1,4-diphenylbutadiyne generates the unusual [2 + 2 + 2] additional organic compound Ph–C≡C–C9H8–Ph in addition to the organometallic compound [Cp*Ru(η6-C6H5–C≡C–C≡C–Ph)][BF4]. [C9H9-η6-C6H4(RuCp*)–C6H4(RuCp*)-η6-C9H9][BPh4]2 is generated after the reaction of compound [C9H9-η6-C6H4(RuCp*)–C6H4(RuCp*)-η6-C9H9][BF4]2 with Na[BPh4]. The structure of this compound was confirmed by X-ray diffraction. A possible approach to form Ph–C≡C–C9H8–Ph and [Cp*Ru(η6-C6H5–C≡C–C≡C–Ph)][BF4] is suggested.
Graphical Abstract Formal [2 + 2 + 2] addition reaction of [Cp*Ru(H2O)(NBD)]BF4 (NBD = norbornadiene) with 4,4′-Diethynylbiphenyl generates [C9H9-η6-C6H4(RuCp*)–C6H4(RuCp*)-η6-C9H9][BF4]2. The reaction of [Cp*Ru(H2O)(NBD)][BF4] with 1,4-diphenylbutadiyne simply generates unusual [2 + 2 + 2] additional organic compound Ph–C≡C–C9H8–Ph in addition to the organometallic compound [Cp*Ru(η6-C6H5–C≡C–C≡C–Ph)][BF4]. [C9H9-η6-C6H4(RuCp*)–C6H4(RuCp*)-η6-C9H9][BPh4]2 is generated after the reaction of compound [C9H9-η6-C6H4(RuCp*)–C6H4(RuCp*)-η6-C9H9][BF4]2 with Na[BPh4]. The structure of this compound was confirmed by X-ray diffraction. And the possible approach to form Ph–C≡C–C9H8–Ph and [Cp*Ru(η6-C6H5–C≡C–C≡C–Ph)][BF4] was suggested.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
14.
Nina I. Giricheva Georgiy V. Girichev Michail S. Fedorov Sergey N. Ivanov 《Structural chemistry》2013,24(3):807-818
A combined gas-phase electron diffraction/mass-spectrometric and quantum chemical (B3LYP/cc-pVTZ, MP2/cc-pVTZ) study of the molecular structures of para-methylbenzenesulfonic acid (4-MBSA) and meta-nitrobenzenesulfonic acid (3-NBSA) was carried out. On the basis of mass spectrometric analysis, it was found that the substituted benzenesulfonic acids are thermostable at least up to 431(3) K. The fragmentations of 4-MBSA and 3-NBSA molecules under electron impact were analyzed. Quantum chemical calculations show that the 4-MBSA molecule exists as an enantiomeric pair, which is formed as a result of rotation of OH group about the S–O(H) bond. The 3-NBSA molecule has two conformers with different orientations of the O–H bond with respect to the nitro group and two corresponding enantiomers. The equilibrium configurations of 4-MBSA and both conformers of 3-NBSA have similar structures of the SO3H group, with the O–H bond eclipsing one of the S=O bonds. Selected experimental bond distances for 4-MBSA/3-NBSA are (Å) r h1(C–C)av = 1.403(3)/1.395(4); r h1(C–S) = 1.765(5)/1.784(5); r h1(S=O)av = 1.433(4)/1.438(4); and r h1(S–O) = 1.618(4)/1.620(4). The potential functions for the internal rotation of SO3H, OH, and CH3 or NO2 groups were calculated, and the transition states between enantiomers (conformers) were determined. The influence of substituent's nature on molecular geometry as well as on the energies of frontier orbitals and red-ox properties of the compounds is discussed. The inductive and mesomeric substituent effects were estimated from the donor–acceptor interaction energies of the natural bond orbitals of substituent and benzene frame. The correlation between group electronegativities and cooperative energetic characteristics of inductive and mesomeric effects of substituents is shown. 相似文献
15.
The reaction of gold(III) neutral complexes AuBr(CN)2(N–N) {N–N = 2,2′-bipyridine (bpy), 5,5′-dimethyl-2,2′-bipyridine (Me2bpy), 1,10-phenanthroline (phen)} with a stoichiometric amount of K[AuCl4] · 2H2O in nitromethane at room temperature led to the formation of 1:1 electrolytes which were characterized by NMR and IR spectroscopy,
conductivity measurements, elemental analyses and X-ray diffraction. Both the anions and the cations of these salts are singly
charged square-planar Au(III) complexes and the cations have general formula [AuCl2(N–N)]+. A hypothesis on the possible reaction mechanisms is presented to give an explanation for the formation of the reaction products. 相似文献
16.
Abstract The molecular and crystal structure of a 1:1 co-crystal of 4,4′-dimethyl-7,7′-bi([1,2,5]thiadiazolo[3,4-b]pyridylidene)–chloranilic acid, (1), has been determined by X-ray diffraction at the monoclinic space group P21/c with cell parameters of a = 8.422(6), b = 7.343(4), c = 16.112(7) ?, β = 104.988(8)°, V = 962.5(10) ?3 and Z = 2. In the crystal structure, two components connect via the intermolecular O–H···N hydrogen bonds [2.804(4) ?] and S···O
heteroatom interaction [2.945(3) ?] with R
2
2(7) couplings to form a unique and infinite one-dimensional supramolecular tape structure. The calculations of (1) at the HF/6-31G(d), MP2/6-31G(d), and B3LYP/6-31G(d) levels can almost reproduce X-ray geometry. In addition, the distances
of the intermolecular O–H···N and S···O interactions by MP2/6-31G(d) and B3LYP/6-31G(d) levels agree well with those in the
crystal. The calculated binding energies corrected BSSE and ZPE are −4.487 (HF), −7.473 (MP2), and −5.640 (B3LYP) kcal/mol.
The results suggest that the complex (1) is very stable and the dispersion interaction is significantly important for the attractive intermolecular interaction in
(1). The NBO analysis has revealed that the n(N) → σ*(O–H) interaction gives the strongest stabilization to the system and the major interaction for the intermolecular
S···O contact is n(O) → σ*(S–N).
Index Abstract In the crystal structure of the title compound, the molecules are linked by intermolecular O–H···N hydrogen bonds and short
S···O heteroatom interactions with R
2
2(7) couplings to construct a unique and infinite one-dimensional supramolecular tape structure.
相似文献
17.
Zhi Qiang Shi Ning Ning Ji Ren Gao Zhao Ji Kun Li Zhi Feng Li 《Structural chemistry》2011,22(1):225-233
Two new copper(II) complexes, [Cu(p-FBA)2(2,2′-bpy)]·(H2O) (1) and [Cu(p-FBA)(2,2′-bpy)2]·(p-FBA)2 (2) {p-FBA = p-fluorobenzoic acid, 2,2′-bpy = 2,2′-bipyridine} have been obtained from an identical starting mixture using temperature as
the only independent variable and characterized by X-ray single crystal diffraction as well as with infrared spectroscopy,
elemental analysis, and thermogravimetric analysis. The results reveal that 1 has 1D infinite chain structure formed by O–H···O hydrogen bonds, while 2 features a 0D structure. Additionally, there exist C–H···O hydrogen bonds and π–π stacking interactions in 1, forming 2D supramolecular structure. Furthermore, density functional theory (DFT) calculations of the structures, stabilities,
orbital energies, composition characteristics of some frontier molecular orbitals and Mulliken charge distributions of the
[Cu(p-FBA)2(2,2′-bpy)] of 1 and [Cu(p-FBA)(2,2′-bpy)2]+ cation of 2 were performed by means of Gaussian 03W package and taking B3LYP/lanl2dz basis set. 相似文献
18.
Paul Rademacher 《Structural chemistry》2006,17(1):19-25
The electronic and geometrical structures of fluorocyclopropanes (1–12) have been analysed using DFT B3LYP calculations. A linear relationship, Δɛω=−0.172 Δr−0.171 (n=12, R=0.931), between Δɛω (in eV), the difference of the energies of the Walsh orbitals ωS and ωA, and Δr (in pm), the difference of vicinal and distal C–C bond lengths, is established. Correcting the orbital splitting by the basic value at Δr=0.00 pm, an even better linear correlation Δɛω
eff=0.0720 Δr (n=12, R=0.984) is obtained. The results confirm the general applicability of the two-orbitals model for the relationship between geometrical and electronic structures for substituted cyclopropanes.
1For Part 4 see Ref. [17]. 相似文献
19.
Thermal behavior of xGa2O3–(50 − x)PbO–50P2O5 (x = 0, 10, 20, and 30 mol.% Ga2O3) and xGa2O3–(70 − x)PbO–30P2O5 (x = 0, 10, 20, 30, and 40 mol.% Ga2O3) glassy materials were studied by thermo-mechanical analysis (TMA) and differential thermal analysis (DTA). Replacement of
PbO for Ga2O3 is accompanied by increasing glass-transition temperature (263 ≤ T
g/°C ≤ 535), deformation temperature (363 ≤ T
d/°C ≤ 672), crystallization temperature (396 ≤ T
c/°C ≤ 640) and decreasing of coefficient of thermal expansion (5.1 ≤ CTE/ppm K−1 ≤ 16.7). Values of Hruby parameter were determined (0.1 ≤ K
H ≤ 1.3). The thermal stability of prepared glasses increases with increasing of concentration of Ga2O3. 相似文献
20.
Santanu Mandal Ashok Kumar Rout Guillaume Pilet Debasis Bandyopadhyay 《Transition Metal Chemistry》2009,34(7):719-724
Two new mononuclear complexes of copper(II), namely [CuL2] (1) and [CuL′2] (2) have been synthesized by reacting copper perchlorate with furfurylamine and salicylaldehyde or 2-hydroxyacetophenone, where
L = (2-hydroxybenzyl-2-furylmethyl)imine and L′ = (2-hydroxymethylbenzyl-2-furylmethyl)imine, the respective asymmetric bidentate
Schiff bases that are formed in situ to bind the Cu(II) ion. The complexes have been characterized by elemental analysis,
IR spectroscopy and single crystal X-ray diffraction studies. Structural studies reveal that the mononuclear units of both
the complexes (1) and (2) adopt square planar geometry supported by weak intermolecular C–H···π interactions. 相似文献