Linked Pyridines

Bipyridines with the nitrogens located at various positions on the rings, as in 3,3'-bipyridine (15), 4,4'-bipyridine (16) and 3,4'-bipyridine (17) have been studied as bridging ligands. 4,4'-bipyridine can be synthesized in 78 yield from 4-bromopyridine using NaH, Ni(O2CHCH3)2, NaOC(CH3)3, and PPh3 in (CH3OCH2)2 at 45 C. Purification is accomplished by chromatography on silica gel using a 50 50 mixture of petroleum ether diethyl ether as eluent.38 3,3'-Bipyridine (15) has been used to bridge...

Septipyridine Octipyridine Novipyridine Decipyridine

The cycloaddition-retrocycloaddition chemistry used to prepare (37) can be employed to prepare (76a-c) in quite respectable yields of 79 , 60 , and 78 , respectively.90 1. Wilkinson, G. (Ed.) Comprehensive Coordination Chemistry Pergamon Oxford, UK, 1987, Vol. 2, p 91. 2. Thompson, A. M. W. C. Coord. Chem. Rev. 1997, 160, 1-52. 3. Chelucci, G. Thumel, R. P. Chem. Rev. 2002, 102, 3129-3170. 4. Potts, K. T. Ralli, P. Theodoridis, G. Winslow, P. Org. Synth. 1986, 64, 189-195. 5. Jameson, D. L....

H3l23

In which intermolecular complementary hydrogen bonding with two sets of NH-donors and N-acceptors plays pivotal roles Scheme 10 .41'4 Various guest molecules can be included in the cavities of molecular aggregates in the crystals. Another feature of benzimidazole-containing ligands is the ability to tune the redox potential by remote site deprotonation.15'43 The oxidation potential of the Ru complex Ru H2L5 2 2 is sensitive to solution pH.44 This change arises from the proton-coupled electron...

Info

The tetraphosphine Ph2P 2CHC6H4CH PPh2 2 109 could readily be prepared by nucleophilic reaction of Ph2PCH2C6H4CH2PPh2 with BuLi at -40 C, followed by quenching of the lithiated intermediate with Ph2PCl.225 The same conditions could then be applied to the intermediate triphosphine, affording 109 as an air-sensitive white solid.225 Alternatively, albeit in lower yield, slow addition of LiPPh2 to a,a,a',a'-tetrabromo-p-xylene also gave 109 . The penultimate step in the synthesis of the new...

Syntheses Of Metal Diketonates

Although the synthesis of a metal -diketonate and its stoichiometry depend largely on the reaction conditions, such as choice of solvent, temperature, and pH of the solution, as well as on the mode of isolation of the pure complex, some general conditions can be outlined.1'2'7'8'61 This method is useful only for electropositive elements such as alkali metals, alkaline earths, and aluminum. Diketones react with these metals, in anhydrous aromatic solvents, with evolution of molecular hydrogen...

Metalcatalyzed Coupling Reactions 11221 Homocoupling of halopyridines

The most useful transition metal-mediated halopyridine homocouplings make use of a Ni0 catalyst,20 most often generated in situ through reduction of a Ni11 complex. This method provides product in much higher yield than the classic Ullmann reaction and is compatible with many functional groups. For example, the chiral bipyridine 8 was generated in 91 yield via Ni-catalyzed homocoupling of the pyridyl chloride, 7 Scheme 1 .21 Reactions that employ

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Her. 1888, 21, 1077-1078. 2. Gerdeissen, Her. 1889, 22, 244-254. 3. Waiden, Jr., G. H. Hammett, L. P. Chapman, R. P. J. Am. Chem. Soc. 1931, 53, 3908. 4. Richter, F. Smith, G. F. J. Am. Chem. Soc. 1944, 66, 396-398. 5. Smith, G. F. Cagle, F. W., Jr. J. Am. Chem. Soc. 1947, 69, 781-784. 6. Smith, G. F. Richter, F. P. Phenanthroline and Substituted Phenanthroline Indicators, their Preparation, Properties, and Applications to Analysis G. F. Smith Chemical Co, Columbus, OH, 1944. 7....