Carbethoxymethyne (EtOCOC:) has been generated by the short wavelength photolysis of diethylmercury bisdiazoacetate, (N2CC02Et)2Hg + hv -* 2EtOCOC: + 2N2 + Hg, and its reactions with cyclohexene, c/s-2-butene, and rra«s-2-butene were investigated. The carbyne, formed in its 2 ground state, adds to the olefinic bond in a spin allowed but, according to INDO MO calculations, orbital symmetry forbidden concerted step with retention of the geometrical configuration of the parent olefin to yield a cyclopropyl radical. Parallel to addition, preferential insertion into the allylic C-H bonds also occurs yielding an alkyl radical. Thus, the basic chemical behavior of doublet ground state carbynes appears to bear a close resemblance to that of singlet carbenes. The cyclopropyl and alkyl radicals undergo free radical combination and hydrogen abstraction reactions with solvent molecules. The hydrogen abstraction reaction of cyclopropyl radicals is stereoselective and occurs from the sterically less hindered side of the ring, resulting in the preponderant formation of the less stable endo product. In the longer wavelength photolysis of the source compound N2 is eliminated in a stepwise fashion and a singlet state mercury carbene, which is capable of insertion and stereospecific addition, is formed. Cleavage of the C-Hg linkage in the source compound results in the formation of ethyl diazoacetate which was detected and monitored during the photolysis by infrared spectroscopy. The effect of conversion and wavelength of photolysis on product yields and the relative importance of the various competing primary modes of decomposition were investigated and the overall mechanism is discussed.arbon free radicals constitute the most common and frequently encountered class of organic intermediates. The chemistry of the trivalent, divalent, and to a lesser extent of the zerovalent carbon radicals, the simplest representatives of which are H3C•, H2C:, and the free carbon atom, respectively, comprises one of the fundamental pillars of modern organic chemistry. Little, however, is known about the family of monovalent carbon radicals, the carbynes. The simplest of

Die Synthesen der drei Bipyridy1‐Ru(II)‐Komplexe (I)‐(III), die hydrolytisch stabile oberflächenaktive Bindungen und verschiedene Molekülladungen besitzen, sowie die Eigenschaften ihrer monomolekularen Schichten werden beschrieben Der oberflächenaktive Ligand 4,4′‐Di‐n‐nonadecylbipyridin‐(2,2′) wird durch Raney‐ Ni‐Kupplungsreaktion aus 4‐n‐Nonadecylpyridin, Alkylierungsprodukt vom 4‐Methyl‐ pyridin‐Carbanion mit n‐Octadecylchlorid (Ausb. 43%), in l4proz. Ausb. dargestellt.

Surfactant ruthenium complexes are attracting attention as potential photoinduced electron-transfer reagents, especially for possible light energy storage schemes. The ester derivatives i(bpy)2RuH[bpy(COORi)(COOR2)]|2+ (where bpy = 2,2'-bipyridine, the carboxy substituents are in the 4,4' positions, and Rt = R2 = CigH37 (I); R3 = C18H37, R2 = H (111); and Ri = C18H37, R2 = C2H5 (IV)) have been prepared and characterized. The alkaline hydrolysis of I to octadecanol and 11 (Rt = R2 = H), with III as an intermediate product, proceeds more rapidly in monolayers and in 50% aqueous THE than does that of the water-soluble analogue V (R¡ = R2 = C2H3) in aqueous solution. Both the surface pressure-area characteristics and luminescence of monolayers of the surfactant compounds spread on aqueous subphases depends strongly on dissolved anions; even traces of strongly interacting anions such as perchlorate lead to condensation of the films, while luminescence is ~20-fold more intense in the presence of perchlorate as compared with chloride. When the monolayers are transferred to glass slides, the pretreatment of the glass affects the extent of dark ester hydrolysis. Prolonged photolysis of monolayer assemblies on glass in contact with water leads to a slow (quantum yield, ~5 X 10-6) nonhydrolytic degradation of the complex, but to no detectable water dissociation (quantum yield for H2 production, <1 X 10-4).

No abstract

Reverse-phase paired-ion high performance liquid chromatography (HPLC) has been used to determine diester, monoester-monocarboxylate and dicarboxylate derivatives of tris(2,2'-bipyridyl)ruthenium(II) (Run(bpy)32+) which can be distinguished on the basis of water solubility and molecular charge. Positively charged surfactant ruthenium derivatives have been ion-paired with methanesulfonate anions in the aqueous tetrahydrofuran mobile phase while their water soluble analogues have been paired with n-heptanesulfonate anions to provide suitable retention for separation on a C18 bonded column. Using optical detection at 280 nm, the lower limit of sensitivity is 1 X 10~12 mol with ±2% precision at the 2.5 X 10~9 mol level. Monitoring hydrolysis reactions of diester derivatives of Ru1I(bpy)32+ by HPLC has proven superior to absorption and emission spectrometry.