Organometallic heterocycles structural studies

The family of photoreducible dyes (e.g, acridinium, xanthene, thiazinium among other classes of dyes) produce excited states of essentially quinoidal structures which can act as efficient acceptors of electrons. Amines [59], sulfur compounds, especially sulfmate salts [60], heterocycles of low ionization potential [61], alkylcarboxylates and stable enolate anions [62], and several classes of organo-metallic compounds, notably allylic and benzylic organostannanes [63], represent classes of compounds which have proved efficacious as coinitiators in electron transfer sensitization with these dyes. Electron transfer with the organometallics was unambiguously established in a series of model studies involving electron acceptors of the anthracene class [64],... 

The tetrameric Zr complexes [Zr(0H)2(H20)2L]4X8 (L = bipyridyl, phenanthroline, various Schiff-bases X = Cl, NCS) were the presumed products from the reaction of ZrOCl2 with various heterocyclic bidentate ligands.336 The interaction of H20 with Zr0(C104)2 or Zr0(N03)2 was probed by NMR spectroscopy.337,338 In the latter case, the cation [Zr4(0H)8(H20)i6]8+ (80) was proposed as the product.338 The related trimer [Zr02Ci2H8(/u2-0H)]3(//3-0)Li5(THF)g(H20)5 (81) was isolated from the hydrolysis product of an organometallic precursor. X-ray structural data confirmed the planarity of the six-membered Zr3(/r2-OH)3 core.339 In related work, protometric studies of Zr hydroxide complexes have probed thermodynamic stability,340 while FT IR and theoretical investigations have addressed the details of laser-ablated group IV metal atoms that... 

Spectra-structure correlation charts showing the probable positions of the characteristic absorption frequencies of some 1000 aliphatic, aromatic, and heterocyclic compounds [ ], together with various classes of aliphatic and organometallic derivatives in the 15-to 35-/1 region, are shown in Figs. 3 and 4. Some of the important classes of compounds studied and summarized in these correlation charts are alkanes, alkenes, cyclopropanes, cyclopentanes, cyclohexanes, substituted benzenes, polynuclear hydrocarbons, heterocyclics. 

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