Pyridine ferrocenyl complex

Keywords pyridine ferrocenyl complex, Suzuki coupling... 

Disubstituted pyridine/pyrimidine ferrocenyl complexes have been obtained by mechanically (mortar and pestle) induced Sukuzi coupling reactions in the solid state. The solventless process is much faster, and more selective, than the same reaction carried out in solution (040RM2810). The synthesis and structure of the complex [Fe(ri -C5H4-4-C5H4N)(Ti -C5H4-3-C4H3N2)] are reported as a test case. 

The preparation of ferrocenyl substituted pyridines, such as 4-ferrocenylpyiidine and l,r-di(2-pyiidyl)feiTocene (L), allowed the preparation of complexes with formula [Rh(cod)L2]CI04. The multitopic ligands, A,A -bis[(A)-prolyl)phenylenediamine, A,A -bis [(A)-pyrrolidin-2-yl]methyl)phenylenediamine, A,Af -bis[(6 )-A-benzylprolyl]phe-nylenediamine, and A,A -bis [(A)-Af-benzyl-pyrrolidin-2-yl]methyl)phenylenediamine, were synthesized and their coordination properties with Rh(i) studied. The ligand bis(bipyridine)-calix[4]arene (BBPC) reacted with 2 equiv. of [Rh(nbd)2]BF4 or [Rh(nbd)(CH3CN)2]BF4 yielding the bimetallic compound [Rh(nbd)(BBPC)]2[BF4]2 396. ... 

Naturally, it is possible to synthesise a similar ligand system without central chirality and in fact without the unnecessary methylene linker unit. A suitable synthesis starts with planar chiral ferrocenyl aldehyde acetal (see Figure 5.30). Hydrolysis and oxidation of the acetal yields the corresponding carboxylic acid that is transformed into the azide and subsequently turned into the respective primary amine functionalised planar chiral ferrocene. A rather complex reaction sequence involving 5-triazine, bromoacetal-dehyde diethylacetal and boron trifluoride etherate eventually yields the desired doubly ferrocenyl substituted imidazolium salt that can be deprotonated with the usual potassium tert-butylate to the free carbene. The ligand was used to form a variety of palladium(II) carbene complexes with pyridine or a phosphane as coligand. 

It should be noted that a number of SPC polymers which contain other heterocycles have been prepared, motivated by their promising optical or electrical properties. Examples include pyridine (65) [123], pyrrole (66) [124], oxadiazole (67) [125], selenophene (68) [126], benzo[2,l,3]thiadiazole (69) [127], benzo[2,l,3]selenadiazole (70) [126], perylene bisimide (71) [128], 1,4-diketo- pyrrolo[3,4-c]pyrrole-l,4-dione (72 and 73) [127,129], and triphenyleamine (74) [127] as part of the polymer backbone by SPC (Figure 19c). Specifically for metal complexation, porphyrin [130], difluoroboraindacene [131], bipyridine [132], phenanthroHne [113], terpyridine [133, 134], and the like [123] were embedded in the backbone. In this context, an interesting report was submitted by Rehahn et al., in which l,l -ferrocenyl units were incorporated into a PPP (Figure 22.20). Due to a low-energy barrier for rotation around the Cp-Fe-Cp axes (Cp = cyclopentadienyl), the obtained polymer 75 was assumed to take randomly coiled conformations [135]. 

The experimental PHIP studies and DFT calculations were also combined to explore the chemistry of Rh(I) complex possessing a chiral ferrocenyl phosphine thioether bidentate ligand [130]. The relative stability of the [Rh(P,S Bu)L2] (L = MeOH, pyridine, or MeCN (P,S Bu) = CpFe[q5-i,2-C5H3(PPh2)(CH2S Bu)]) complexes, their ability to form dihydrides upon interaction with H2, the relative stability of the products, and the mechanisms of the site exchange in the dihydrides were addressed. 

Photoexcitation (X = 313 nm) of the charge-transfer adducts of N with CuBr(Py)(PPh3) or Cu[HB(Pz)3] in hexane (Py = pyridine, Pz = 1-pyrazolyl) gives rise to Q with = 0.37-0.65. The photorearrangement of the complexes of N with halo(ferrocenyl-diphenylphosphine)copper(I) tetramers... 

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