Oligo bridges

The hydrolysis products of cis- and trans-DDP are known to undergo condensation reactions with formation of di- and oligo-p-OH species [11,15]. However, for geometric reasons less robust OH bridged species are expected for trans compounds compared to the cyclic species formed by the cis isomer [11]. 

OLIGO-2-PYRIDYLAMIDES AS BRIDGING LIGANDS IN POLYNULEAR LINEAR COMPLEXES... 

Oligo- and polymethylene-bridged complexes can be prepared by reaction of metal carbonyl anions with w.w -dihaloalkanes. This method proved to be a simple entry to the iron series /j,-(CH2)j.][(t75-C5H5) Fe(CO)2]2 (x s 3) (283), but yielded quite different products in the case of Na[(T 5-C5H5)Mo(CO)3] (283) and Na[Mn(CO)s] (284). An alternative two-step synthesis of the iron compounds involves the preparation of the mononuclear w-haloalkyls LXM—(CH2)X—X, and a subsequent... 

Indelli, M. T., Chiorboli, C., Flamigni, L., De Cola, L., Scandola, E, Photoinduced electron transfer across oligo-p-phenylene bridges. Distance and conformational effects in Ru0I) Rh0II) dyads. Inorg. Chem. 2007, 46, 5630-5641. 

In the context of oligo-fluorene (oFL) molecular wires, we will conclude with an outlook that focuses on donor-acceptor conjugates bearing Ceo electron-accepting units and zinc porphyrin (ZnP) or ferrocene (Fc) electron-donating moieties, respectively. Both, the donor and acceptor are covalently connected by oFL bridges of variable length. 

Several years later Schanze and Cabana reported a study of the distance dependence of photoinduced ET in a second series of oligo-proline bridged dyads (51a-c, Scheme 22 and Table 4) [126,127]. In this study the authors were able to study photoinduced ET in CH3OH, a solvent that is demonstrated to stabilize the extended conformation of the proline spacers [126]. Rate constants for forward ET in 51a-c are determined by using luminescence decay techniques, and an overall distance dependence of 3 = 1.0 A 1 is obtained from the rate data (Table 4). By... 

Fig. 25 The series of dyads, 29(n), possessing the oligo-p-phenylenevinylene bridge that were used to investigate the switchover from superexchange characteristics to molecular wire behaviour in the photoinduced electron transfer reaction, from the locally excited state of tetracene (TET) donor to the pyromellitimide (PI) acceptor.148 Also, shown are a schematic of the photoinduced charge separation rate versus, donor-acceptor distance (lower left-hand side) and the LUMO energies of TET and the various bridges (lower right-hand side).

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