Phenanthroline alkylation

Classic A/-heterocychc ligands, eg, bipyridyl (bipy), terpyridyl, imidazole, pyrazine, phenanthroline, piperazine (including alkyl- and aryl-substituted derivatives), and polypyrazol-l-yl-borates (bis, tris, and tetra), have all been found to coordinate Th(IV) chlorides, perchlorates, and nitrates. The tripodal hydrotris(pyrazolyl)borates, HBPz, have been used to stabilize organometaHic complexes (31). Bis-porphyrin Th(IV) "sandwich" complexes have been... 

Amorphous (most likely atactic) 3,4-polyisoprene of 94—100% 3,4-microstmcture was prepared with a (C2H 3A1—Ti(0—/ -C Hy) catalyst (11). Crystalline 3,4-polyisoprene containing about 70% 3,4-units and about 30% i7j -l,4-microstmcture was prepared using a catalyst derived from iron acetyl acetonate, trialkyl aluminum, and an amine in benzene (37). However, this polyisoprene contained gel and was obtained in poor yield. Essentially gel-free crystallizable 3,4-polyisoprene of 70—85% 3,4-microstmcture with the remainder being cis-1,4 microstmcture was prepared in conversions of greater than 95% with a water-modified tri alkyl aluminum, ferric acetyl acetonate, and 1,10-phenanthroline catalyst (38). The 3,4-polyisoprene is stereoregular and beheved to be syndiotactic or isotactic. 

Abbreviations acac, acetylacetonate Aik, alkyl AN, acetonitrile bpy, 2,2 -bipyridine Bu, butyl cod, 1,5- or 1,4-cyclooctadiene coe, cyclooctene cot, cyclooctatetraene Cp, cyclopentadienyl Cp, pentamethylcyclopenladienyl Cy, cyclohexyl dme, 1,2-dimethoxyethane dpe, bis(diphenyl-phosphino)ethane dppen, cis-l,2-bis(di[Atenylphosphino)ethylene dppm, bis(diphenylphosphino) methane dppp, l,3-bis(diphenylphosphino)propane eda,ethylenediamine Et,ethyl Hal,halide Hpz, pyrazole HPz, variously substituted pyrazoles Hpz, 3,5-dimethylpyrazole Me, methyl Mes, mesityl nbd, notboma-2,5-diene OBor, (lS)-endo-(-)-bomoxy Ph, phenyl phen, LlO-phenanthroline Pr, f opyl py, pyridine pz, pyrazolate Pz, variously substituted pyrazolates pz, 3,5-dimethylpyrazolate solv, solvent tfb, tetrafluorobenzo(5,6]bicyclo(2.2.2]octa-2,5,7-triene (tetrafluorobenzobanelene) THE, tetrahydrofuran tht, tetrahydrothicphene Tol, tolyl. 

Dendrons 21-23 are easily prepared on a multi-gram scale and are highly soluble in common organic solvents thanks to the presence of the four long alkyl chains per peripheral fullerene unit. Therefore, they appear to be good candidates for the preparation of fullerene-rich macromolecules, for example, as shown by their attachment to a phenanthroline diol derivative and the preparation of the corresponding copper(I) complexes (see below). 

Homogeneous Processes with Tris-phenanthroline Metal(III) Oxidants. The rates of electron transfer for the oxidation of these organometal and alkyl radical donors (hereafter designated generically as RM and R, respectively, for convenience) by a series of tris-phenanthroline complexes ML33+ of iron(III), ruthe-nium(III), and osmium(III) will be considered initially, since they have been previously established by Sutin and others as outer-sphere oxidants (5). 

For a particular iron(III) oxidant, the rate constant (log kpe) for electron transfer is strongly correlated with the ionization potential Ip of the various alkylmetal donors in Figure 4 (left) (6). The same correlation extends to the oxidation of alkyl radicals, as shown in Figure 4 (right) (2). [The cause of the bend (curvature) in the correlation is described in a subsequent section.] Similarly, for a particular alkylmetal donor, the rate constant (log kpe) for electron transfer in eq 1 varies linearly with the standard reduction potentials E° of the series of iron(III) complexes FeL33+, with L = substituted phenanthroline ligands (6). 

Dioxo-l,4,7,10-tetrahydro-l,10-phenanthroline (72) with dimethyl sulfate gives l,4-dihydro-7-methoxy-l-methyl-4-oxo- 1,10-phenanthroline (73) rather than a quaternary salt, steric hindrance presumably preventing alkylation of both nitrogens.203 A related alkylation has also been reported.295 1,2,3,4-Tetrahydro-1,10-phenanthrolines similarly form 1-alkyl derivatives rather than 10-alkyl quaternary salts with alkyl halides.38 The rate of methylation of 1,10-phenanthroline with methyl iodide in dimethyl sulfoxide has been studied,296 and the polaro-graphic reduction of 1 -methyl- 1,10-phenanthrolinium iodide was reported.286... 

There has been some interest in the electrical conductivity and magnetic properties of salts of 1,10-phenanthroline and 1-alkyl-1,10-phenanthrolinium cations with 7,7,8,8-tetracyano-p-quinodimethane and its anion radical297-302 and related species.303... 

Phenanthroline and some of its alkyl-substituted derivatives improve the heat stability of polyesters594 and magnetic recording tape.595 They also improve the color of cured polyester resins.596 They are also useful in various electroplating and electrolytic processes597-601... 

We shall consider reactions catalysed by two different types of pro-catalyst the first (type A) employs Pd-allyl cations ([Pd(a]lyl)(PCy3)]+/Et3SiH or [Pd(allyl)(MeCN)2] + ), and the second (type B) employs Pd-alkyl or chloro complexes ([(phen)Pd(Me)(MeCN)]+, where phen = phenanthroline, and [(RCN)2PdCl2]). These two types of catalysts give very different products in the cyclo-isomerisation of typical 1,6-dienes such as the diallyl-malonates (10), Scheme 12.6. Since there is known to be a clear order of thermodynamic stability 11 < 12 <13, with a difference of ca. 3-4 kcal mol 1 between successive pairs, any isomerisation of products under the reaction conditions will tend towards production of 12 and 13 from 11 and 13 from 12. Clearly, when 11 is the major product (as with pro-catalysts of type A), it must be the kinetic product (see Chapter 2 for a discussion of kinetic and thermodynamic control of product distributions). However, when 12 is generated selectively, as it is with pro-catalysts of type B, there is the possibility that this is either generated by rapid (and selective) isomerisation of 11 or generated directly from 10. 

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