C–H and C–O oxidative addition in reactions of aryl carboxylates with a PNP pincer-ligated Rh(i) fragment

Abstract

Reactions of a series of phenyl esters with a (PNP)Rh fragment have been studied. PhO(2)CPh only underwent C-H oxidative addition (OA). PhO(2)CCF(3) chiefly underwent acyl-oxygen OA. PhO(2)CBu(t) and PhO(2)CNEt(2) initially underwent OA of an ortho-C-H bond of the phenyl group but continued thermolysis led to the phenyl-oxygen OA products.

Why is Benzene Unique? Screening Magnetic Properties of C6H6 Isomers

“…The name of benzene is almost an equivalent to the concept of aromaticity; aromaticity of benzene has been investigated extensively both in its ground and excited states. [1][2][3][4][5] Aromaticity is an elusive phenomenon that has been employed by chemists to explain exceptional stability [6][7][8][9][10][11][12][13][14][15][16][17][18][19] or justify particular reactivity of various molecules. [20][21][22][23][24][25] IUPAC recommends four criteria -structural, energetic, electronic, and magnetic (SEEM) -to characterize aromatic species.…”

“…An answer to this question is crucial for the whole chemical community, because the magnetic probes for assessing aromaticity are the most frequently used indices to rationalize stability in terms of aromaticity that is an energetic property of a particular molecule. [13,14,16,18] If electronic energy of molecules correlates with their magnetizability, one can potentially assess the global minimum on a potential energy surface (PES) just by computing or measuring magnetic susceptibility of various isomers of a certain molecule. This tempting approach can be a replacement for sophisticated measurements of atomization energy.…”

Metallapentalenofuran: Shifting Metallafuran Rings Promoted by Substituent Effects

“…As shown in Scheme 2, am echanism for the formation of complex 9 is proposed as follows: at first, the reductive elimination of 8 occurs to give the 16 eo smapentalene intermediate (A), which is subsequently oxidized by FeCl 3 to give the higher valent chloro-osmapentalene intermediate (B). Then, the known deprotonation [12] of the intermediate B gives the osmapentalyne 9 as the final product.…”

“…The solvent CH 2 Cl 2 and phenyl groups on PPh 3 were disordered and refined by using restraints. CCDC 1846 846 (11), 1846847 (12), and 1846845 (13)c ontain the supplementary crystallographic data for this paper.T hese data can be obtained free of charge from The Cambridge Crystallographic Data Centre.…”

“…As the first Craig-type Mçbius metallacycle, [10] osmapentalyne (1,S cheme1)i sa7 -carbon "carbolong complex" [11] with novel reactivity and unique properties. For example,o smapentalyne 1 can undergo an electrophilic addition reactionw ith H + to give the 16 eo smapentalene (2), [12] or with X 2 to give complexes 3 and 4. [13] The cycloaddition of complex 1 with terminal alkynes in the absence or presence of water can occur to give cycloaddition products such as cyclobutametallapentalenes (5) [14] or a-metallapentalenofurans (6), [15] respectively.…”