Two homonuclear

A heteronuclear bond length (one between two different atoms) is equal to the average of two homonuclear bond lengths (one between two like atoms) of the same order (both single, both double, or both triple). 

A number of classical calculations have been attempted for T-R transfer. Parker [44], in 1959, employed a classical model of two homonuclear molecules colliding with coincident planes of rotation. Each molecule contained two centers of repulsion, separated by a distance d and symmetrically placed from the center of mass, and one center of attraction located at the center of mass. The repulsive force was taken to be of the form e-ar, where r is the distance between repulsive centers and a is the steepness parameter. The attractive force was taken to be e- a/2, where R is the distance between centers of mass. This leads to an approximate potential of the form... 

Exercise 4.2. What hydrocarbon cluster is analogous to Co4(CO)i2 Write the main-group and metal isolobal fragments. Write out the compositions and draw the structures of all the mixed Co/C clusters possible between these two homonuclear Co and C clusters. 

In general, the full isotropic coupling tensor between two homonuclear spins i and j can only be preserved by a multiple-pulse sequence if Ui (t) Uj U) [i.e., if fl j (t) = ap(t)] for 0 < / < Tj,. For multiple-pulse sequences with constant rf amplitude this is only possible for spin pairs with small offset differences p - Vj v, that is, for small angles 0-j. In general, the average coupling tensors are nonisotropic. Even if isotropic effective coupling tensors (with c J = c Jy = c 0 and c Jp = 0 for a = p)... 

Ruthenium is an element with two NMR active isotopes Ru and Ru, but only the former is of practical use since it has the lowest quadrupole moment. Ruthenium-101 has a better natural abimdance but the linewidths are about 33 times larger than with Ru. The observability of Ru is three times lower than that of Mo. Only two homonuclear clusters have been reported Ru3(CO)j2 in C6D6 5( Ru)=-1208 with Avi/2 = 80Hz (reference K4[Ru(CN)6] [42] and [HRu3(CO)ii] N(PPh3)2 with two resonances, one at 5( Ru)= —633 and the second at 6( Ru)= —1202 in intensity ratio 2/1 [43]. 

S Nonequivalent homonuclear spins. If two homonuclear spins that are not equivalent are coupled, then when other interactions are present the MAS lineshape will depend on the MAS rate (Wu and Wasylishen 1993). In the case of N in cis-azobenzene dioxide large changes in the lineshape were observed and simulations showed that the lineshape was dependent on the relative orientation of two chemical shift tensors and their orientation with respect to the intemuclear vector. 

The photoinduced cleavage of metal-metal bonds is now a general reaction that finds many synthetic applications e.g., many heteronuclear metal-metal bonded complexes are most conveniently prepared by irradiating solutions containing a mixture of two homonuclear compounds. A discussion of such reactions is given in 13.3, organized according to the type of metal involved. This chapter then closes with discussions of photoinduced electron-transfer reactions and pulse-radiolysis techniques. 

Surprisingly little work has been carried out on the resolution of homochiral helicates into the two enantiomers. Self-resolution upon crystallization has been observed for two homonuclear triple helicates [37,38], but there seem to be only two well-authenticated cases of enantiomeric resolution, both using antimonyl tartrate the complex [ 02(9)3] " , a dinuclear triple helix [39], and a trinuclear double helical complex of iron(ll) [Fe3(19)2] " with a tm-terpyridyl ligand [40]. The circular dichroism spectrum of [ 02(9)3] " is shown in Figure 13. 

Consider a system comprising only two homonuclear spin- /2 nuclei, I and S, that exist in a rigid molecule which tumbles isotropically in solution, that is, it has no preferred axis about which it rotates. The two nuclei do not... 

The ratio of the translational partition functions is virtually 1 (because the masses nearly cancel explicit calculation gives 0.999). The same is true of the vibrational partition functions. Although the moments of inertia cancel in the rotational partition functions, the two homonuclear species each have er = 2, so... 

The formula given for Ag3Pn corresponds to the case where the two lone electron pairs are both associated with P atoms forming three homonuclear P - P bonds. The valence electron rules specify oniy the number of lone election pairs per formula unit. Some or all of the lone electron pairs might therefore be on the P atoms having two homonuclear bonds. 

Rogl and Nowotny (1978) have observed that the type of homonuclear linkage in borides can be correlated in simple form with the metal boron ratio of the compound. All ternary rare earth-transition metal borides are listed in table 20, arranged according to decreasing metal boron ratio, and the observed homonuclear linkage of the B atoms. One notes that if the ratio is larger than 1.75 only isolated B atoms occur. Boron dumbbells are found with values between 1,3 and 1.0. Two homonuclear bonds occur first with a metal to boron ratio of 1 and three... 

The results described here are from the initial stages of a program designed to study the structure and properties of liquid-vapor surfaces of systems composed of polyatomic species. Both computer simulation and perturbation theory methods are the tools used to obtain these results. Here we report molecular dynamics (MD) computer simulations of two homonuclear diatomic liquids, each at a temperature in the region of the triple point. The liquid-vapor surface of systems of monatomic molecules has been the subject of considerable investigation ( -2.) the past few years, but as far as we are aware, this is the first work of this type on molecular species. 

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