Condensation reactions of indole with acetophenones affording mixtures of 3,3-(1-phenylethane-1,1-diyl)bis(1H-indoles) and 1,2,3,4-tetrahydro-3-(1H-indol-3-yl)-1-methyl-1,3-diphenylcyclopent[b]indoles

Condensation of indole 1a with eight acetophenones 8a–h in ethanolic HCl afforded the corresponding mixtures of condensation products: 3,3-(1-phenylethane-1,1-diyl)bis(1H-indoles) 11a–h (2:1 condensation of indole:acetophenone, –H₂O) and diastereomers of substituted 1,2,3,4-tetrahydro-3-(1H-indol-3-yl)-1-methyl-1,3-diphenylcyclopent[b]indoles 12a–h and 13a–h (2:2 condensation of indole:acetophenone, –2H₂O). Each mixture was analyzed by ¹H NMR. The use of substituted electron-withdrawing acetophenones favored formation of 2:1 condensation products, whereas the use of substituted electron-donating acetophenones favored formation of 2:2 condensation products. Increased reaction temperature gave higher 2:2 condensation yields, but temperatures above 40?°C were unfavorable, giving complex, tarry mixtures.     

5‐Iodobenzofurazan 1‐oxide: polymorphs,pseudosymmetry and disorder

5‐Iodobenzofurazan 1‐oxide (systematic name: 5‐iodobenzo‐1,2,5‐oxadiazole 1‐oxide), C₆H₃IN₂O₂, occurs in two polymorphic forms, both monoclinic in P2₁/c with Z′ = 2. The intermolecular interactions in the two polymorphs are quite different. In polymorph (I), there are strong intermolecular I...O interactions, with I...O distances of 3.114 (8) and 3.045 (8) Å. In polymorph (II), there are strong intermolecular I...N interactions, with I...N distances of 3.163 (4) and 3.175 (5) Å. In (I), there is about 15% disorder in one molecule and about 5% in the other. In both polymorphs, there are pseudosymmetric relationships between the crystallographically independent molecules.     

Superoxo, peroxo, and hydroperoxo complexes formed from reactions of rhodium porphyrins with dioxygen: thermodynamics and kinetics

Rhodium(II) porphyrin complexes react with dioxygen to form terminal superoxo and bridged mu-peroxo complexes. Equilibrium constants for dioxygen complex formation with rhodium(II) tetramesitylporphyrin ((TMP)Rh*) and a m-xylyl-tethered dirhodium(II) diporphyrin complex (*Rh(m-xylyl)Rh*) are reported. (TMP)Rh-H reacts with oxygen to form a transient hydroperoxy complex ((TMP)Rh-OOH), which reacts on to form the rhodium(II) complex ((TMP)Rh*) and water. Kinetic studies for reactions of (TMP)Rh-H with O2 suggest a near concerted addition of dioxygen to the (TMP)Rh-H unit. Reactivity studies for mixtures of H2/O2 and CH4/O2 with the dirhodium(II) complex (*Rh(m-xylyl)Rh*) are reported.     

Hydrogen‐Atom Transfer in Reactions of Organic Radicals with [CoII(por)]. (por=Porphyrinato) and in Subsequent Addition of [Co(H)(por)] to Olefins

Do the hydrogen shuffle! DFT calculations and experiments reveal low‐barrier multistep pathways for hydrogen‐atom transfer from organic radicals to [Co^II(por)] ^. to form [Co(H)(por)], and for the radical pathway leading to net olefin insertion into the Co? H bond of [Co(H)(por)] (see scheme). The results suggest that hydrogen‐atom‐transfer pathways could be important in numerous addition reactions of M? H complexes with unsaturated substrates.

     

Activation of CH bonds by octaethylporphyrinrhodium dimer

Octaethylporphyrinrhodium dimer, [RhOEP]₂, reacts thermally with arylmethyl CH bonds to produce octaethylporphyrinbenzylrhodium compounds.     

Competitive O-H and C-H oxidative addition of CH3OH to rhodium(II) porphyrins

Rhodium(II) porphyrins react with CH(3)OH in benzene by alternate mechanisms that give H-CH(2)OH and H-OCH(3) bond activation in different methanol concentration regimes which is a rare example of transition metal reactivity with methanol.     

Structure Determination of the Products from the Acid-Catalyzed Condensation of Indole with Acetone

Four of the previously reported compounds obtained from the acid-catalyzed condensation of indole with acetone are now assigned the following structures: cis-4,4a,9,9a-tetrahydro-2-(1H-indol-3-yl)-4,4-dimethyl-3H-carbazole (2a), 1,1',4,4'-tetrahydro-1,1,1',1'-tetramethyl-3,3'(2H,2'H)-spirobi[cyclopent[b]indole] (4), 4,4a-dihydro-2-(3-1H-indolyl)-4,4-dimethyl-3H-carbazol-4a-ol (7), and 5-(2-aminophenyl)-1,3,4,5-tetrahydro-1,1,4,4-tetramethylcyclopent[kl]acridine (8). The structure of the novel rearrangement product 8 was solved by an X-ray crystal structure determination. The two previously reported autoxidation products of 4 are now assigned the following structures: 1,3',4,4'-tetrahydro-1,1,4',4'-tetramethyl-cis-dispiro[cyclopent[b]indole-3(2H),2'(5'H)-furan-5',3"-[3H]-indol]-2"(1"H)-one (5) and 1,4-dihydro-1,1,5',5'-tetramethylspiro[cyclopent[b]indole-3(2H),3'(4'H)-1-benzazocine]-2'(1'H),6'(5'H)-dione (6).     

Anionically cross linked homopolymer colloids applied in formation of platinum nanoparticles

Diprotonic sulfuric and succinic acids react efficiently with the tertiary amine sites in polydimethylaminoethylmethacrylate (PDMAEMA) to produce polymer colloid nano-particles held together by dinegatively charged anions that cross link the partially protonated PDMAEMA homopolymer. This procedure is used to encorporate [PtCl(6)](2-) as a cross linker into the framework of well defined polymer network colloid particles that have dual roles as nanoreactors and a source of protective polymer coating. Reduction of the cross linking [PtCl(6)](2-) groups produces platinum metal nano-particles (1.12(.25)nm) that are relatively small and narrowly dispersed. Formation of colloid particles by reaction of diprotic acids with homopolymers that have proton accepting centers provides a convenient intentional route to incorporate a variety of homopolymers into self assembled polymer network materials for applications as nanoreactors and transport systems.     

Reduction of carbon monoxide by [(TMTAA)Rh]2 to form a dimetal ketone complex

Benzene solutions of [(TMTAA)Rh](2) (1) react with CO (P(CO) = 0.8-20 atm; T = 298 K) by cleaving the Rh(II)-Rh(II) bond to form dirhodium(III) ketone (TMTAA)Rh-C(O)-Rh(TMTAA) [2; ν(CO) = 1726 cm(-1); (1)J(103)Rh(13)C(O)(103)Rh = 45 Hz]. Thermodynamic values for the reaction of 1 with CO to form 2 were evaluated from equilibrium constant measurements [K(1)(298 K) = 5.0(0.6) × 10(3), ΔG(1)°(298 K) = -5.0(0.1) kcal mol(-1), ΔH(1)° = -14(1) kcal mol(-1), and ΔS(1)° = -30(3) cal K(-1) mol(-1)].