Ferrocene dicarboxylic acids

Figure 10.6 The intramolecular interstrand H-bonding pattern in amino acid conjugates of disubstituted Fc derivatives results in the formation of 10-membered rings for ferrocene dicarboxylic acid conjugates, 12-membered rings forFca-conjugates, and 14-membered rings for ferrocenediamine conjugates. Reproduced by permission from Ref. 50 of The Royal Society of Chemistry.

A nice example of grinding-induced crystal engineering is the formation of a hydrogen bonded cocrystal between ferrocene dicarboxylic acid and 1,4-diazabicyclo [2.2.2] octane (DABCO). The ferrocene dicarboxylic acid exists in the solid as a hydrogen bonded dimer based on two repeats of the carboxylic acid dimer synthon (solid A). Grinding with DABCO (solid B) gives rise to a new solid, C, in which the carboxylic acid dimers have been broken and replaced by an acid-amine synthon, Figure 8.25.30... 

Figure 8.25 Solid-solid or solid-vapour synthesis of a hydrogen bonded co-crystal between ferrocene dicarboxylic acid and 1,4-diazabicyclo [2.2.2] octane (reproduced by permission of The Royal Society of Chemistry).

Mercurioferrocenes (290) and (291) are separable by Soxhlet extraction and these may be used to prepare bromoferrocene or dibromoferrocene or the iodo analogs. Alternatively, these halogenated ferrocenes are prepared from the ferrocene boronic acids or from anions (322) or (323). Bromoferrocene is the starting material for cyanoferrocene, azidoferrocene, or aminoferrocenes, generally in the presence of a copper salt. Amtnoferrocene can be acylated to produce an amide, or converted to isocyanoferrocene by a formylation/dehydration sequence (Scheme 96). The 1,T-diisocyanoferrocene is available from the bis(acyl)azide, itself derived from ferrocene dicarboxylic acid. ... 

It also was found that the direction of the photobiocatalytic switch of the nitrospiropyran-FAD-reconstituted enzyme is controlled by the electrical properties of the electron transfer mediator. With ferrocene dicarboxylic acid as a diffusional electron transfer mediator, the enzyme in the nitrospiropyran-FAD state (10a) was found to correspond to the OFF state bio-catalyst, while the protonated nitromerocyanine state of the enzyme (10b) exhibits ON behavior. In the presence of the protonated 1-[1-(dimethyl-amino )ethyl]ferrocene, the direction of the photobioelectrocatalytic switch is reversed. The nitrospiropyran-enzyme state (10a) is activated toward the electrocatalyzed ox idation of glucose, while the protonated nitromerocyanine enzyme state (10b) is switched OFF, and is inactive for the electrochemical oxidation of glucose. This control of the photoswitch direction of the photoisomerizable reconstituted enzyme was attributed to electrostatic interactions between the diffusional electron mediator and the photoisomefizable unit... 

Ferrocene dicarboxylic acid and 3-thiophene acetic acid 314-316... 

The possibility of different chemical behaviour of polymorphic modifications has been explored before only in the case of indomethacine amorphous and crystal forms reacted with ammonia by StoweU, Griesser, Bym et al. [62]. We have investigated two rather different systems, namely the polymorphic forms of barbituric acid [63] and of ferrocene dicarboxylic acids [64], which have been reacted with... 

Triphenylantimony dichloride, 1,1 -ferrocene dicarboxylic acid disodium salt IF 30-60 7 X lo" 2... 

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