Ordinary Bonds Research Articles

A NEW FAMILY OF BINUCLEAR MOLYBDENUM(V) AND TUNGSTEN(V) CHALCOHALIDES

Abstract A number of chalcohalide complexes of molybdenum and tungsten having the unusual composition MS2X3(SeX2) (X = Cl, Br) have been synthesized. Their structure has been studied by vibrational spectroscopy, 35Cl and 79Br NQR methods, magnetic measurements and X-ray structure analysis for the bromide compounds. The compounds are dimeric; the metal atoms (d1) in them are bonded directly by an ordinary bond and bridging S2 ligands, coordinated perpendicular to the metal-metal bond. The coordination of the SeX2 (X = Cl, Br) ligands is unusual; the selenium atom, as donor, is bonded to the metal and, as acceptor, to two bridging halogen atoms.

The effect of electron deficit on the geometry of sulphide bridged methylcyclopentadienylmetal tetrahedra. Synthesis, physicochemical characteristics, and molecular structures of Cp′ 3Cr 3(μ 3-S) 4Co(CO), Cp′ 4Cr 4(μ 3-O)(μ 3-S) 3+ ZnCl 3·C 4H 8O −, and Cp′ 4V 4S 4 (Cp′ = π-CH 3C 5H 4)

A diamagnetic electron-saturated cluster, Cp′ 3Cr 3(μ 3-S) 4Co(CO) (I), was obtained by heating a heterotrinuclear cluster, Cp′ 2Cr 2SCMe 3(μ 3-S) 2Co(CO) 2 (Cp′ = π-CH 3C 5H 4), in heptane in the presence of diphenylacetylene. The treatment of (Cp′CrSCMe 3) 2S with anhydrous ZnCl 2 in THF led to an electron-deficient cationic cluster, Cp′ 4Cr 4(μ 3-O)(μ 3-S) + 3 (II), with one unpaired electron (ZnCl 3 · thf − is the anion). Interaction between Cp′ 2V and t-butylmercaptan in boiling heptane gives Cp′ 4V 4S 4 (III) which is a new member in the family of cubane clusters, Cp 4M 4S 4, and contains an electron-deficient metal tetrahedral skeleton with two unpaired electrons. The structure of compounds I–III was determined by an X-ray diffraction study. I contains the metal tetrahedral Cr 3Co skeleton which is flattened down the axis joining Co and the centre of the Cr 3 base (CrCo 2.692(4), CrCr 2.816(3) Å). The μ 3-S bridge is located above each face (CoS average, 2.171(6) Å; CrS average, 2.255(5) Å). The Co atom is also linked to the terminal CO group (CoC 1.82(2) Å). and each Cr atom is bonded to the π-CH 3C 5H 4 (CrC average, 2.29(2) Å. The cationic cluster in II is a distorted tetrahedron in which the CrCr bonds at the sulphide bridge faces (average, 2.765(2) Å) are longer than those at the oxygen bridge face (average, 2.687(2) Å). The CrO bonds (average, 1.994(5) Å) are shorter than the CrS bonds (average, 2.224(3) Å), and both are shorter than their counterparts in the neutral cluster, Cp′ 4Cr 4(μ 3-O)(μ 3-S) 3·CuBr 2 described previously, presumably because of the enhancement of π-bonding in both OCr and SCr bonds. This interaction is particularly noticeable in III, which has a strongly electron-deficient metal V 4 skeleton (VS average, 2.292(3) Å) which gives rise to short VV distances (average, 2.867(3) Å). The molecule of III is sterically not strained, the VC distances (average, 2.28(1) Å) being close to distances expected for ordinary bonds. The physicochemical properties of I–III and the specific features of bonding peculiar to these clusters in relation to the electron deficit of their metal skeletons are discussed.

Quantum-chemical semiempirical calculations of 1-methylsilatrane

To ascertain the nature of the transannular Si /l arrow/ N bond in molecules of the atrane type and the possibility of its description in semiempirical MO methods we calculated the 1-methylsilatrane (I), trimethylamine (II), triethylamine (III), triethanolamine (IV), trimethoxymethylsilane (V), triethoxymethylsilane (VI), and N,N-dimethylaminotrimethoxysilane (VII) molecules by the CNDO/2 and INDO methods (in sp and spd bases) and the MNDO method (in the sp basis). On the basis of an analysis of the electron density distribution and the compositions of the MO it was concluded that the transannular bond is due to the formation of a three-center N-Si-C/sub ax/ bond and an interaction with donor-acceptor character with the participation of the 3d AO of silicon and is weaker than the ordinary Si-N chemical bond in VII.

Dynamic bond percolation theory: A microscopic model for diffusion in dynamically disordered systems. I. Definition and one-dimensional case

A dynamic bond percolation model is defined and studied. The model is intended to describe diffusion of small particles (ions, electrons) in a medium which is statistically disordered (as in ordinary bond percolation), but which is also undergoing dynamic rearrangement processes on a timescale short compared to the observation time. The model should be applicable to polymeric solid electrolytes, where the orientational motions of the polymer (which are responsible for configurational entropy) cause the dynamic motion of the medium (polymer) in which the small particles (alkali ions) diffuse. The model is characterized by three parameters: an average hopping rate w which appears in the master equation for hopping, a percentage of available bonds f, and a mean renewal time τ̄ren for dynamic motion of the medium to rearrange the assignments of closed and open bonds. We show that the behavior is always diffusive for observation times long compared to τ̃ren, in agreement with experiment on polymeric solid electrolytes. We also derive a closed-form expression for the diffusion coefficient. For observation times smaller than the renewal time there is no diffusion, again in accord with the behavior of polymeric solid electrolytes below the glass transition temperature. The diffusion coefficient is a monotonically increasing function of the inverse renewal time and hence of the free volume, the configurational entropy, and the temperature.

Floating Rate Notes and Immunization

As shown in several of those papers, the appropriate immunizing duration is a function of the assumption regarding the stochastic process describing the man? ner in which the term structure of interest rates changes. The theory has been well developed for ordinary bonds. This paper extends the existing literature on duration and immunization to a different type of security, the floating rate note. The floating rate note (FRN) is a debt security in which coupon payments adjust according to changes in interest rates. The coupons are closely tied to cur? rent short-term spot rates, with the result that prices of FRNs are always at or near par value. They became popular in this country in 1974 with a Citieorp issue

Linear-Combination-of-Atomic-Orbitals Band Theory and the Second-Nearest-Neighbor Electron Interaction

The concept of the second-nearest-neighbor electron (SNE) interaction has been introduced recently to explain the piezoelectric constants and Szigeti effective charges. But the idea of SNE interaction is criticized because of the lack of warrant for actual existence of it. This paper gives the relative strength of the SNE interaction energy in diamond using the LCAO band theory of J.C. Slater. The SNE interaction energy is 42% of the ordinary chemical bond energy in diamond.

Neutron scattering spectra of hydridocarbonyls in the 900–200 cm–1energy region

It is shown that neutron scattering spectroscopy is a powerful technique for characterizing vibrations of hydrogen atoms in simple and complex transition metal hydridocarbonyls. The spectra of HCo(CO)4, H2Fe(CO)4, HMn(CO)5, HCo(PF3)4, KHFe(CO)4, H3Mn3(CO)12 and CsHFe3(CO)11 are recorded and discussed, and a neutron “selection rule” is used to assign vibrations in the first three compounds. It is found that the hydrogen bending vibration for a hydrogen atom in a three centre-two-electron bond, is little displaced from that in an ordinary bond.

PREMIUMS ON CONVERTIBLE BONDS: COMMENT

The Journal of FinanceVolume 25, Issue 4 p. 928-930 Comment PREMIUMS ON CONVERTIBLE BONDS: COMMENT G. A. Mumey, G. A. MumeyKrannert Graduate School of Industrial Administration, Purdue University.Search for more papers by this author G. A. Mumey, G. A. MumeyKrannert Graduate School of Industrial Administration, Purdue University.Search for more papers by this author First published: September 1970 https://doi.org/10.1111/j.1540-6261.1970.tb00568.xCitations: 2 Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article.Citing Literature Volume25, Issue4September 1970Pages 928-930 RelatedInformation

A study of imidazole by the proton magnetic resonance method

The concentration dependence of the chemical shifts of the protons of imidazole in six polar organic solvents and water has been studied. In aqueous solutions an exchange of the NH protons between the imidazole and the water molecules takes place. In organic solvents, the position and half-width of the NH line of imidazole depend on the concentration. With an increase in the concentration, this line shifts in the downfield direction. The shift δ (1 ppm for a solution of imidazole in DMSO) may be due to the formation of an ordinary hydrogen bond (> NH ⋯ N ≤) between the imidazole molecules.

Approximate relationship between the energy characteristics of the valence states of atoms and their effective charges in a diatomic molecule with an ordinary sigma bond

Approximate relationship between the energy characteristics of the valence states of atoms and their effective charges in a diatomic molecule with an ordinary sigma bond

Splitting of the vibrational frequencies of the multiple bonds of symmetrical molecules

1. The vibrational spectra of symmetrical molecules containing equivalent multiple bonds was investigated. 2. The interaction of multiple bonds is not detected in the vibrational spectra when two intermediate ordinary bonds C-C are present in the molecule. 3. The splitting of the frequencies of the symmetrical and antisymmetrical vibrations of multiple bonds separated by oxygen and nitrogen atoms was studied (anhydrides of carboxylic acids, peroxides, imides). The causes of splitting of the frequencies were elucidated, and a physical interpretation was given. The conclusion was drawn that the force field in one group of atoms may depend substantially on the coordinates of the atoms in another, extremely distant part of the molecule.

Inhibited Oxidation of Elastomers

Abstract 1. The oxidation of elastomers in the presence of true inhibitors, of which secondary aromatic amines are an important class, is for practical purposes an initiation reaction and primary oxidation of the chains is possible only to a slight degree. 2. Inhibited oxidation (initiation) is fundamentally distinct from autocatalytic oxidation. 3. The method of study of inhibited oxidation (initiation) consists in the study of the consumption of inhibitor, while the rate of this process is equal to either the proportional rate of initiation or the constancy of the concentration of dissolved oxygen in the entire mass of the rubber film or specimen studied. 4. In the inhibited oxidation of different types of rubber, the rate of initiation is practically constant for each temperature. The activation energy of the reaction is equal to 22.6 kcal. per mole, and is independent of the nature of the polymer in the absence of electrically negative substituents in the polymer. 5. In the case of strongly activated nitration, the diffusion of oxygen in the rubber may have a retarding influence. Then the concentration of dissolved molecular oxygen [O2] differs at different depths below the surface. The relation of the rate of consumption of inhibitor wi to the concentration of oxygen is a straight-line function, i.e., wi=A[O2]n; at 120° C, n=0.5. 6. The reactivity of rubber hydrocarbons with respect to molecular oxygen and certain other chemically active agents is determined principally by the content of double bonds in the main chains of the molecules of the polymers. Marked structural differences, such as degree of polymerization, spatial configuration, presence of aromatic rings, etc., have practically no influence on the rate of inhibited oxidation. 7. The absorption of oxygen by the double bonds of the side chains of butadiene rubbers has a much higher activation barrier (27–28 kcal. per mole); consequently, the double bonds are practically inactive during the inhibited oxidation of elastomers. 8. The oxidation of polyisobutylene in the presence of phenyl-2-naphthylamine is characterized by the presence of a temperature threshold, below which initiation does not take place. The directly related change of molecular weight and consumption of inhibitor indicate that destruction of the polymer continues until a constant molecular weight is reached. 9. The inhibited oxidation of Butyl rubber is characterized by the simultaneous progress of two rates of oxidation. The first is the rate of oxidation of the chains, which do not reach a constant weight; the second is the rate of absorption of oxygen at the double bonds. In both polyisobutylene and Butyl rubber, the ordinary bonds of the long chains are considerably weakened. Since the concentration of ordinary bonds in Butyl rubber is much higher than the concentration of double bonds, the rate of oxidation of the former is greater than the rate of oxidation of the latter.

The Effect of Taxation on Securities

retical effect of a tax upon the ordinary corporation bond. The two generally recognized taxes in the United States affecting such a bond are direct personal property taxes and income taxes. The personal property tax is generally imposed upon the principal of the bond. The income tax is imposed upon the interest the bond bears. To realize the effect of a personal property tax upon the principal of the bond, take the hypothetical case of a bond owned in a state having no personal property tax and no income tax. If such a state were to pass a law imposing a 1 per cent tax upon the principal of a $1,000 bond bearing 5 per cent the owner would be obliged to pay $10 in taxes each year. This would reduce the income on the bond from $50 to $40 a year. If the state, instead of enacting the personal property tax just stated, were to pass an income tax law taxing the bond owner 20 per cent upon the interest of the bond, the owner would be obliged to pay $10 in taxes each year. This would make exactly the same reduction in his income from the bond, which would then yield only $40 a year. It may be seen, therefore, because as a general proposition all taxes are paid out of income, that it is immaterial, in considering the effect of a tax on the bond, whether the tax is based upon its principal or income. If the owner of the bond