Ferrocene-containing 1,3-disubstituted

Ferrocene-containing co-polyesters, preparation, 12, 350 Ferrocene-containing liquid crystals dendrimers, 12, 235 disubstituted ferrocenes, 12, 227 hydrogen-bonded ferrocene derivatives, 12, 234 monosubstituted ferrocenes, 12, 222 polycatenar ferrocenes, 12, 234 properties, 12, 221... 

A number of organometallic polymers containing metallocenes and metallocene analogues has been well-known for some time2. Because of the features of high-temperature stability and radiation resistance of the ferrocene nucleus, ferrocene-containing polymers are of special interest. Basically, these polymers may be divided into two classes the metallocene moiety is either located in a pendant group or in a backbone of the polymer chain. The former polymers have been synthesized by vinyl polymerization of vinyl metallocene monomers such as vinylferrocene. The latter polymers have been prepared by polycondensation of l,l -disubstituted metallocenes or metallocene dihalides with a.w-disubstituted monomers, and fell into two main types, (A) and (B). 

UV data collected from substituted ferrocene systems have been summarized by Rosenblum (68) and some analysis of the electronic transitions involved has been provided. Until recently, little use had been made of the extensive tabulation of UV data of various substituted ferrocenes found in the literature. Several Russian workers have now attempted a qualitative correlation of the absorption bands of a series of mono- (20) and 1,1 -disubstituted (19) ferrocenes with the nature of the substituent. For each of the four different absorption bands observed in the spectra of these substituted ferrocenes, both bathochromic and hypsochromic shifts were exhibited for those ferrocenes containing electron-donating or -withdrawing... 

Fig. 6-1. Schematic representation of a ferrocene-containing macrocycle with the ferrocene moiety appended to the macrocycle. Fc = 1-substituted or l,l -disubstituted ferrocene x = O, S, or NR m,n,p= 1, 2, or 3 y = number of ferrocene units attached (usually between 1 and 4).

Fig. 9-12. First 1,3-disubstituted ferrocene-containing liquid crystals (15 and 16) and non mesomorphic 1,3-disubstituted ferrocene derivatives 17.

Fig. 9-21. Unsymmetrically l,l -disubstituted ferrocene-containing thermotropic liquid crystals and examples of their transition temperatures.

Synthesis and mesomorphic properties of the first ferrocene-containing side-chain liquid crystalline polymers, 69, obtained by grafting either a 1,1 - or a 1,3-disubstituted ferrocene derivative functionalized by a vinyl group onto a polysiloxane have been reported [155J. These polymers showed enantiotropic SmC and/or SmA mesophases. 

Malacea R, Routaboul L, Manorrty E, Daran J-C, Poli R (2008) Synthesis, characterization and crystal structures of two new platinum complexes with planar chiral 1,2-disubstituted ferrocenes containing phosphine and thioether donor groups. J Mol Struct 890 249-254... 

ZnCl2/HCI-catalyzed polymerization of (dimethylamino)methylferrocene. However, the resulting material was of low molecular weight (M 2400), and a mixture of 1,2-, and M -disubstituted ferrocene units was found to be present in the main chain 78). Recently, however, the synthesis of well-defined polymers of structure 29 (M 18,000-139,000) containing face to face ferrocene units with naphthalene bridging groups was achieved (79). 

Deschenaux and co-workers also isolated liquid crystalline polysiloxanes containing ferrocene in their side chains.236 These polymers contained either 1,3- or l,l -disubstituted ferrocene and were synthesized from the reaction of preformed polysiloxanes and vinyl organo-iron monomers. 

The hydrosilylation strategy has also been used to prepare well-characterized sidepolymers containing ferrocene [60]. Grafting of vinyl-terminated mesogens onto poly(methylhydrosiloxane-r-dimethylsiloxane) yielded materials with 1,T- (2.27a) and 1,3-disubstituted (2.27b) ferrocene units... 

Although an o-disubstituted ferrocene is chiral, very often (but not always) the ferrocenyl fragments employed contain a group bearing a stereogenic carbon atom. One early example was provided by Togni, Spindler and co-workers (Scheme 2.45). 

Liquid-crystalline polysiloxanes containing 1,3- or l,l -disubstituted ferrocene moieties in their sidechains were also synthesized through a reaction of vinyl organometallic monomers with preformed polysiloxanes. " The synthesis of one such liquid-crystalline metal-containing polysiloxane 55 is shown in scheme 17. 

In 1963, Rausch reported the synthesis of polymercuriferrocenylene (88) via reaction of 1,1-dichloromercuriferrocene (87) with either ethanolic sodium iodide or aqueous sodium thiosulfate. This mercury-based polymer could be decomposed to give mono- and disubstituted ferrocenes in addition to ferrocene itself. Neuse and Crossland later reported that polymercuriferrocenylene could be converted to relatively low molecular weight polyferrocenylene (86) by reacting the mercury-containing polymer (88) with ferrocene (73) at 245-260°C as shown in Scheme 21. ... 

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