Trans-systemic complexity

Rhenium forms a number of mono-oxo, CTs-dioxo, and trans-dioxo complexes in oxidation states IV through VII. Reversible, proton-independent, one-electron potentials for several systems are represented in Table 1 [13-22, 35, 36]. As is the case forTc, a large change in E° for a given redox step can be produced by changing the ancillary ligands. 

Apart from a comparison of the cis and trans dichloro complexes and a comparison of dichloro with chloroaquo species, little has been done to study the effect of the non-amine, monodentate non-participating ligands upon the lability of Rum complexes. Where studied, cis-dichlorotetra-(amine) complexes are considerably more labile than their trans isomers but there are insufficient data at this time to say whether there is any great sensitivity of lability to the nature of the tetraamine ligand in such systems. The extremely low reactivity of irans-[Ru(cyclam)Cl2]+ (the rate constant for Cl- exchange is reported293 to be 3 x 10 7s 1 at 102 °C) seems to be an exception that is, as yet, unexplained. Some relevant data are collected in Table 11. 

Green has also used the method of H+ addition to a -CHO-substituted (allyl)metal complex for the preparation of (s-trans-diene) complex derivatives of a Group 8 metal. The Ru complex 35 was synthesized in that way.33 Stable [(s-tra ,s-r 4-conjugated diene) Ru(acac)2] isomers have been described34 and related [(s-tra s-r 4-diene)Ru(trispyrazolylbo-rate)Cl] systems are stable and isolable.35 Eventually, Mashima et al. have described the reaction of all-tra ,s-l,8-diphenyloctatetraene with [Ru(acac)3] under reducing conditions. A dimetallic complex (36) was isolated and characterized by X-ray diffraction, that contained a linear array of two (s-tra ,s-r 4-diene)Ru subunits36 (see Scheme 10). 

In addition, the experimental observation of (.s-tra/u-i7 -diene)metal-locene complexes is kinetically facilitated by the special appearance of the energy prohle of the dienemetallocene system. For the parent system there is evidence (27-31) that the stable (butadiene)ZrCp2 isomers [about equal amounts of (s-trans- (3a) and (s-cu-T -butadiene)zirconocene (Sa) are obtained under equilibrium conditions (22, 23)] are connected through a reactive (T7 -butadiene)zirconocene intermediate (4a) which rapidly equilibrates with s-trans diene complex 3a, but is separated from the (s-cis-diene)metalIocene isomer Sa by a rather substantial activation barrier (Fig. 1). 

Tlie final stage of the light reactions is catalyzed by photosystem I, a trans-membrane complex consisting of about 14 polypeptide chains and multiple associated proteins and cofactors (Figure 19.19). The core of this system is a... 

According to Kegan, few people achieve the capacity for the degree of complexity described by level 5, which is referred to as trans-systemic. At this level, one s perspective is considered incomplete, or as only one aspect of the fuller narrative. One s ways of knowing are open to being influenced by—and potentially enriched in consideration of—those of another. 

Reaction of the alkenyl carbene complex 117, derived from tetra-O-benzyl-aldehydo-D-hbose, with cyclohexene oxide in the presence of [Cp2TiCl]2 gave the oxa-trans-decalin complex 118, together with a smaller proportion of the epimer at the asterisked carbon. This work was extended to the use of sugar epoxide 119 and the carbene complex 120 to give the dioxabicyclo-system 121. ... 

Zadeh, L A., Outline of a new approach to the analysis of complex systems and decision processes , Trans. Systems Man and Cybernetics, IEEE, 1973, SMC-3, pp. 28-44. 

Organohalides (usually with Csp -X bonds) and Pd(0) readily participate in ligand coupling processes. Pd(0) is readily oxidised to Pd(ll), with simultaneous oxidative addition into the C-Br bond, to givea c/s-organopalladium complex, which rapidly equilibrates to the trans-system. 

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