Login In
1985 Volume 1 Issue 6
1985, 1(06): 493-503
doi: 10.3866/PKU.WHXB19850601
Abstract:
The FT-IR and Raman spectra for (TTA)_4LnQH(Q=quinoline) series were measured and discussed as following:
1. Structure and spectra
Due to the similar IR and Raman spectra observed for (TTA)_4LnQHseries there would be the structural analogy for the compounds, i.c. the central ion Ln~(3+) is coordinated with eight oxygen atoms which belong to four TTA groups respective- ly. IR spectra indicates that The hydrogen bond between the nitrogen of quinoline and the oxygen atom of TTA group is formed to make a stable molecular system.
The facts that there is a successive change of Ln-O IR(303-320 cm~(-1)) and Raman (310-323 cm~(-1)) vibrational frequencies with the increase of lanthanide atomic number and the vibrational frequencies of TTA C=O groups coordinated come down to near 1605 cm~(-1) from near 1657 cm~(-1) indicats the existance of hydrogen bond. In addition the low frequency spectra (500-100 cm~(-1)) is discussed in detail.
2. The abnormal spectra of Tb and Tm
...
The FT-IR and Raman spectra for (TTA)_4LnQH(Q=quinoline) series were measured and discussed as following:
1. Structure and spectra
Due to the similar IR and Raman spectra observed for (TTA)_4LnQHseries there would be the structural analogy for the compounds, i.c. the central ion Ln~(3+) is coordinated with eight oxygen atoms which belong to four TTA groups respective- ly. IR spectra indicates that The hydrogen bond between the nitrogen of quinoline and the oxygen atom of TTA group is formed to make a stable molecular system.
The facts that there is a successive change of Ln-O IR(303-320 cm~(-1)) and Raman (310-323 cm~(-1)) vibrational frequencies with the increase of lanthanide atomic number and the vibrational frequencies of TTA C=O groups coordinated come down to near 1605 cm~(-1) from near 1657 cm~(-1) indicats the existance of hydrogen bond. In addition the low frequency spectra (500-100 cm~(-1)) is discussed in detail.
2. The abnormal spectra of Tb and Tm
...
1985, 1(06): 504-510
doi: 10.3866/PKU.WHXB19850602
Abstract:
The termolecular reaction H_2+2I→2HI has been studied by quantum chemi- cal pseudopotential ab initio method. The transition state was assumed to be li- near:
I ——R_2 H ——R_1 H ——R_2 I
The reaction system was represented by a wave function consisting of two confi- gurations, i.e.
ψ=C_1ψ1+C_2ψ_2
where ψ_1 and ψ_2 are determinants describing the electronic state of reactant and product respectively. By solving a second order secular equation for fixed values of R_1 and R_2, we can obtain a point on the potential energy surface. Keeping R_1 constant and varying R_2 (or vice versa), an energy ...
The termolecular reaction H_2+2I→2HI has been studied by quantum chemi- cal pseudopotential ab initio method. The transition state was assumed to be li- near:
I ——R_2 H ——R_1 H ——R_2 I
The reaction system was represented by a wave function consisting of two confi- gurations, i.e.
ψ=C_1ψ1+C_2ψ_2
where ψ_1 and ψ_2 are determinants describing the electronic state of reactant and product respectively. By solving a second order secular equation for fixed values of R_1 and R_2, we can obtain a point on the potential energy surface. Keeping R_1 constant and varying R_2 (or vice versa), an energy ...
1985, 1(06): 511-516
doi: 10.3866/PKU.WHXB19850603
Abstract:
The interracial tension of water/kerosene with added AP type polyoxyethyle- ne-polyoxypropylene block copolymers has been determined, as a function of con- centration of copolymer at 298 K and as a function of temperrature at fixed con- tent of copolymer. The result shows that the AP type polyoxyethylene-polyoxypro- pylene block copolymers exhibit a high interracial activity. The effects of EO con- tent and PO distribution in the AP type copolymers have been investigated. At low concentrations a linear decrease of lnγ as increasing of ln(c+1) was observed. The interfacial tension decreases with increasing temperature sharply. Primary experiments indicate that the AP type copolymers are very effective demulsifiers. The relation between interfacial tension and demulsification effect on several sources of crude oils has also been discussed.
The interracial tension of water/kerosene with added AP type polyoxyethyle- ne-polyoxypropylene block copolymers has been determined, as a function of con- centration of copolymer at 298 K and as a function of temperrature at fixed con- tent of copolymer. The result shows that the AP type polyoxyethylene-polyoxypro- pylene block copolymers exhibit a high interracial activity. The effects of EO con- tent and PO distribution in the AP type copolymers have been investigated. At low concentrations a linear decrease of lnγ as increasing of ln(c+1) was observed. The interfacial tension decreases with increasing temperature sharply. Primary experiments indicate that the AP type copolymers are very effective demulsifiers. The relation between interfacial tension and demulsification effect on several sources of crude oils has also been discussed.
1985, 1(06): 517-527
doi: 10.3866/PKU.WHXB19850604
Abstract:
The electronic energy bands of the charge transfer complex molecular crystal TMPD·(TCNQ)_2 have been calculated. In the calculation,both TMPD and TCNQ are treated as quasi-one-dimensional molecular columns respectively (Figs.1 and 2), and two adjacent molecules are considered as a super-molecule.The method of EHMO/LCAO-MO-CO is used [Eqs.(1)—(5)]. According to the principle of super- conjugation, the methyl group in TMPD is treated as a heteroatom Me with seven electrons. The valence orbital ionization potential I_(Me) and orbital exponent ζ_M of the 2p orbital are given in Eqs.(6) and (7). The results of the frontier and subfrontier energy bands and the energy levels of the corresponding orbitals of the respective isolated molecules (E_(iso)) are shown in Tables 1 and 2.
From Figs.3 and 4, it can be seen that the energy bands of the molecular column TMPD are quasi-double degenerated to a larger extent than those of the columns NMP and TTF. This is because, in these molecular columns, one supermolecule is composed of two molecules, and the intermolecular distance within the column TMPD is larger than those of columns NMP and TTF. It can also be seen that the band E_(HO) of column TMPD jonts with E_(HO-1) at α=0.5, but the band E_(LU) of column TCNQ in crystal TMPD·(TCNQ)_2 does not connect with E_(LU+1). This fact is concerned with the low electrical conductivty of the crystal.
...
The electronic energy bands of the charge transfer complex molecular crystal TMPD·(TCNQ)_2 have been calculated. In the calculation,both TMPD and TCNQ are treated as quasi-one-dimensional molecular columns respectively (Figs.1 and 2), and two adjacent molecules are considered as a super-molecule.The method of EHMO/LCAO-MO-CO is used [Eqs.(1)—(5)]. According to the principle of super- conjugation, the methyl group in TMPD is treated as a heteroatom Me with seven electrons. The valence orbital ionization potential I_(Me) and orbital exponent ζ_M of the 2p orbital are given in Eqs.(6) and (7). The results of the frontier and subfrontier energy bands and the energy levels of the corresponding orbitals of the respective isolated molecules (E_(iso)) are shown in Tables 1 and 2.
From Figs.3 and 4, it can be seen that the energy bands of the molecular column TMPD are quasi-double degenerated to a larger extent than those of the columns NMP and TTF. This is because, in these molecular columns, one supermolecule is composed of two molecules, and the intermolecular distance within the column TMPD is larger than those of columns NMP and TTF. It can also be seen that the band E_(HO) of column TMPD jonts with E_(HO-1) at α=0.5, but the band E_(LU) of column TCNQ in crystal TMPD·(TCNQ)_2 does not connect with E_(LU+1). This fact is concerned with the low electrical conductivty of the crystal.
...
1985, 1(06): 528-532
doi: 10.3866/PKU.WHXB19850605
Abstract:
The visible absorption and fluorescence spectra of metallo derivatives of tetrakis- (ortho-chlorophenyl) porphin (OCITPP) and tetraphenylporphin (TPP) in the pre- sence of 2,4—dinitrochlorobenzene (DNCB) have been studied.Both the absorbance and the fluorescence intensity were found to be lower than those of metalloporphins in the absence of DNDB,indicating the formation of molecular complexes between the donor and the π accepter DNCB. Owing to the reduced molecular symmetry and steric hindrance resulted from the monochloro-substitution at the orthophenyl positions, the binding between the donor and the acceptor for metalloporphins of OCITPP series, was weakened, and hence the fluorescence of metallopophins of OCITPP series was less quenched by DNCB than metalloporphins of TPP series.
The visible absorption and fluorescence spectra of metallo derivatives of tetrakis- (ortho-chlorophenyl) porphin (OCITPP) and tetraphenylporphin (TPP) in the pre- sence of 2,4—dinitrochlorobenzene (DNCB) have been studied.Both the absorbance and the fluorescence intensity were found to be lower than those of metalloporphins in the absence of DNDB,indicating the formation of molecular complexes between the donor and the π accepter DNCB. Owing to the reduced molecular symmetry and steric hindrance resulted from the monochloro-substitution at the orthophenyl positions, the binding between the donor and the acceptor for metalloporphins of OCITPP series, was weakened, and hence the fluorescence of metallopophins of OCITPP series was less quenched by DNCB than metalloporphins of TPP series.
1985, 1(06): 533-542
doi: 10.3866/PKU.WHXB19850606
Abstract:
Based on the studies of IR Spectra of various ZSM-5 zeolites it was found that there are two strong bands at ca. 1875 and 2000 cm~(-1) and their absorbance ratio is a characteristic value. A method to treat the data of IR spectra by using relative absorbance with 2000 cm~(-1) band as a “internal standard” has been develo- ped. The acidity of various ZSM-5 samples has been determined by this method and related to their concentrations of Brönsted acid measured by potential titration and activity of cumeue cracking. od relationships have been found. The assignment of 1875 cm~(-1) and 2000 cm~(-1) bands has been discussed according to the experimental results. The theoretical base of this quantitive method for treating the IR spectra of ZSM-5 zeolite has been found by inferring the relation between relative absorbance and the concentration by the Beer-Lambert law.
Based on the studies of IR Spectra of various ZSM-5 zeolites it was found that there are two strong bands at ca. 1875 and 2000 cm~(-1) and their absorbance ratio is a characteristic value. A method to treat the data of IR spectra by using relative absorbance with 2000 cm~(-1) band as a “internal standard” has been develo- ped. The acidity of various ZSM-5 samples has been determined by this method and related to their concentrations of Brönsted acid measured by potential titration and activity of cumeue cracking. od relationships have been found. The assignment of 1875 cm~(-1) and 2000 cm~(-1) bands has been discussed according to the experimental results. The theoretical base of this quantitive method for treating the IR spectra of ZSM-5 zeolite has been found by inferring the relation between relative absorbance and the concentration by the Beer-Lambert law.
1985, 1(06): 543-546
doi: 10.3866/PKU.WHXB19850607
Abstract:
A sublimation calorimeter has been constructed in our laboratory for solid compounds in pressure range≥0.1 mmHg at 298.15 K. Using this calorimeter and LKB 8700 vaporization calorimeter, the enthalpies of vaporization, ΔH, or the enthalpies of sublimation, ΔH_(sub), of trichorohenzens were measured to be;
Compound ΔH(kJmol)~(-1) ΔH_(sub)(kJmol~(-1))
Water 43.72±0.18
n-Decane 51.21±0.25
Naphthalene 73.26±0.92
1,2,3-Trichlorobenzene 75.14±0.75
1,2,4-Trichlorobenzene 55.06±0.50
1,3,5-Trichlorobenzene 72.68±0.50
A sublimation calorimeter has been constructed in our laboratory for solid compounds in pressure range≥0.1 mmHg at 298.15 K. Using this calorimeter and LKB 8700 vaporization calorimeter, the enthalpies of vaporization, ΔH, or the enthalpies of sublimation, ΔH_(sub), of trichorohenzens were measured to be;
Compound ΔH(kJmol)~(-1) ΔH_(sub)(kJmol~(-1))
Water 43.72±0.18
n-Decane 51.21±0.25
Naphthalene 73.26±0.92
1,2,3-Trichlorobenzene 75.14±0.75
1,2,4-Trichlorobenzene 55.06±0.50
1,3,5-Trichlorobenzene 72.68±0.50
1985, 1(06): 547-555
doi: 10.3866/PKU.WHXB19850608
Abstract:
any studies on rotational distribution of photofragments have been done both in experimental and in theoretical aspects during the past decade, but eomparisions of the theoretical results with the experimental ones remain few and far between. An attempt has been made to emphasize the effects of the repulsive interaction between photofragments on their rotational distribution. A simple classical model was postulated and the interpretation with this model is qualitatively in od ag- reement with a series of experimental observations listed in Table 1. Based on this model, the angular momentum of the photofragments could be divided into two parts: one from the rotation of the parent molecule; the cooling of the parent molecules in a supersonic jet could only affect the first part. The second part depends mainly upon the nature of the dissociative potential surface. Using this simple model, one can also obtain some dynamic informations including some characteristics of the potential surface. A number of examples are given in the discussion, which show that the interpretation with this model is fairly consistent with the results observed in the photolysis of ClCN, BrCN, C_4N_2 etc. in effusive or supersonic molecular beams. This qualitative agreement means that the classical model is helpful if the quantum theory on the rotational distribution of photofragments is not available in practice.
any studies on rotational distribution of photofragments have been done both in experimental and in theoretical aspects during the past decade, but eomparisions of the theoretical results with the experimental ones remain few and far between. An attempt has been made to emphasize the effects of the repulsive interaction between photofragments on their rotational distribution. A simple classical model was postulated and the interpretation with this model is qualitatively in od ag- reement with a series of experimental observations listed in Table 1. Based on this model, the angular momentum of the photofragments could be divided into two parts: one from the rotation of the parent molecule; the cooling of the parent molecules in a supersonic jet could only affect the first part. The second part depends mainly upon the nature of the dissociative potential surface. Using this simple model, one can also obtain some dynamic informations including some characteristics of the potential surface. A number of examples are given in the discussion, which show that the interpretation with this model is fairly consistent with the results observed in the photolysis of ClCN, BrCN, C_4N_2 etc. in effusive or supersonic molecular beams. This qualitative agreement means that the classical model is helpful if the quantum theory on the rotational distribution of photofragments is not available in practice.
1985, 1(06): 556-565
doi: 10.3866/PKU.WHXB19850609
Abstract:
The eigenvalue problem of Hückel matrix including next nearest interaction has been dealt with using graphic method as well as difference equation method respe- ctively.In difference equation approach, a parametric form of equation (10) is obtained and both the coponents of the molecular orbitals Cn and energy levals x have been written formally out as formulas (11) and (13). With large n and small η(|η|<1) the secular equation can be approximated by eq.(16), from which the Taylor expansion (18) of θ in terms of η can be derived. In graphic approach both the characteristic polynomial P_N (x, η) and the C_n(x) are expanded in powers of η by means of theorems~[1] published previously. When |η|<1 the secular equation is reasonably approximated by eq.(32) where terms higher than η~3 have been neglected. Thus a Taylor expansion of x can be formulated as (34). It is easily seen that both approaches are conformed to each other.
As an application of the present results, the role of the next nearest interaction in linear polyene has been investigated in detail where a simple numerical analysis has been done. We see that the next nearest interaction changes the energe levels somewhat, however, the HOMO-LUMO gap Δθ_F, the total energy of electrons E_H and the bond orders are almost kept unchanged. Only the wavefunctions are infuenced which in turn makes the charge density un-uniform; as a result, terminal wave and a charge density wave (CDW) could be predicted.
1985, 1(06): 566-570
doi: 10.3866/PKU.WHXB19850610
Abstract:
By the use of a precision automatic adiabatic calorimeter we have measured the heat capacities for water/silica adsorption system with various adsorbed amoun- ts over the temperature range from 200-320 K.The results obtained show that when the amount of adsorbed water makes the surface coverage (θ) larger than 1, the peak for phase transition of adsorbed water will appear on the C_p-T curves.This means that aggregate of water molecules adsorbed on the surface of silica has for- med. On the other hand when θ<1, no phase transition is observed as the temperature of the system rise and then the C_p—T curves are smooth. These phemomena are in coincidence with molecules on silica surface is weaker than that on the γ-Al_2O_3, the peak profiles for water/silica is sharper than that for H_2O/γ-Al_2O_3 even if the two adsorption systems have the same amount of adsorbed water. The rise in the peak temperature with increase of amount of adsorbed on the surface of silica could become buk water easier as compared with the water adsorbed on the γ-Al_2O_3. Besides, the heat capacities for silica without any adsorbed water over the temperature range from 200 K to 300 K have been obtained by extrapolating the C_p—T curves with various adsorbed amounts at the same temperatures.
By the use of a precision automatic adiabatic calorimeter we have measured the heat capacities for water/silica adsorption system with various adsorbed amoun- ts over the temperature range from 200-320 K.The results obtained show that when the amount of adsorbed water makes the surface coverage (θ) larger than 1, the peak for phase transition of adsorbed water will appear on the C_p-T curves.This means that aggregate of water molecules adsorbed on the surface of silica has for- med. On the other hand when θ<1, no phase transition is observed as the temperature of the system rise and then the C_p—T curves are smooth. These phemomena are in coincidence with molecules on silica surface is weaker than that on the γ-Al_2O_3, the peak profiles for water/silica is sharper than that for H_2O/γ-Al_2O_3 even if the two adsorption systems have the same amount of adsorbed water. The rise in the peak temperature with increase of amount of adsorbed on the surface of silica could become buk water easier as compared with the water adsorbed on the γ-Al_2O_3. Besides, the heat capacities for silica without any adsorbed water over the temperature range from 200 K to 300 K have been obtained by extrapolating the C_p—T curves with various adsorbed amounts at the same temperatures.
THE SDUDY OF THE INTERMEDIATES REACTIONS AND THE REACTION MECHANISM IN THEE THERMOLYSIS OF TETRALINE
1985, 1(06): 571-574
doi: 10.3866/PKU.WHXB19850611
Abstract:
In order to understand more clearly the reaction mechanism in the thermolysis of tertraline, thermal decomposition of some intermediates such as 1-methylindan and butylbenzene were studied.
It follows from the experimental results that the thermolysis of 1-methylindan and butylbenzene proceeds as
The thermolysis of tetraline was affected signficantly when some free radical initiator was added.
These results give not only some enligntenments for elucidating the real paths of tetraline thermolysis but also proofs of some reaction steps in the reaction mechanism.
In order to understand more clearly the reaction mechanism in the thermolysis of tertraline, thermal decomposition of some intermediates such as 1-methylindan and butylbenzene were studied.
It follows from the experimental results that the thermolysis of 1-methylindan and butylbenzene proceeds as
The thermolysis of tetraline was affected signficantly when some free radical initiator was added.
These results give not only some enligntenments for elucidating the real paths of tetraline thermolysis but also proofs of some reaction steps in the reaction mechanism.
1985, 1(06): 575-578
doi: 10.3866/PKU.WHXB19850612
Abstract:
The title compound crystallizes in orthorhombic crystal system with space group P 2_12_12_1, α=0.8983(4) nm, b=1.7538(9) nm, c=1.7603(16) nm and z=4. The crystal structure were solved by direct method. Molecular absolute configurations for two enantiomeric structures were determined by anomalous scattering of Pd~(++) for CuKα radiation. The final R factors are 0.050 for R-(+)-structureand 0.051 for S-(-)-structure.
The title compound crystallizes in orthorhombic crystal system with space group P 2_12_12_1, α=0.8983(4) nm, b=1.7538(9) nm, c=1.7603(16) nm and z=4. The crystal structure were solved by direct method. Molecular absolute configurations for two enantiomeric structures were determined by anomalous scattering of Pd~(++) for CuKα radiation. The final R factors are 0.050 for R-(+)-structureand 0.051 for S-(-)-structure.
1985, 1(06): 579-585
doi: 10.3866/PKU.WHXB19850613
Abstract:
This paper suggests a method for the determination of the ionic hydration num- bers, The method is based on the selectivity of the ion exchange membrane for ion to pass through.Only one kind of ions—anions or cations is allowed to get across the membrane, when an ion exchange membrane is used as an electrolysis membrane.
Three factors causing the volume change of solution in electrode compartment are counted here: (1) the transference of water which are carried by transferring ions, (2)the transference of ions, (3) the electrode reaction. By means of the measured volume change of solution in the anode or cathode compartment, minus the volume change caused by the latter two factors, the transferring volume of water can be obtained, then the transferring mole numbers of water can be calculated. The transferring mole numbers of ions can be calculated from the neasurement of quantities of electricity. The transferring mole numbers of water were divided by the transferring mole numbers of ions, that is the ionic hydration number.
...
This paper suggests a method for the determination of the ionic hydration num- bers, The method is based on the selectivity of the ion exchange membrane for ion to pass through.Only one kind of ions—anions or cations is allowed to get across the membrane, when an ion exchange membrane is used as an electrolysis membrane.
Three factors causing the volume change of solution in electrode compartment are counted here: (1) the transference of water which are carried by transferring ions, (2)the transference of ions, (3) the electrode reaction. By means of the measured volume change of solution in the anode or cathode compartment, minus the volume change caused by the latter two factors, the transferring volume of water can be obtained, then the transferring mole numbers of water can be calculated. The transferring mole numbers of ions can be calculated from the neasurement of quantities of electricity. The transferring mole numbers of water were divided by the transferring mole numbers of ions, that is the ionic hydration number.
...
