Volume 40, Issue 2

Previously prepared (J. Mol. Catalysis 11, 353 (1981)) polystyrene/ruthenium systems have been examined by EXAFS, TEM, IR and Raman spectroscopy. A structure based on small metal clusters bound to the polymer by single ruthenium-arene binding is proposed. The general validity of the approach has been confirmed by preparing a similar product when starting with poly-1- vinylnaphthalene in the place of polystyrene. Both systems are active for the hydrogenation of a large variety of unsaturated groups such as olefinic double bonds, mononuclear aromatic hydrocarbons, ketones, nitriles, nitroaromatic compounds and oximes. Catalytic activity, chemio- and stereoselectivity are discussed in terms of the proposed structure.

Stereoselective glycosylations of 2,3:5,6-di-O-ethylboranediyl-α-D-mannofuranosyl bromide (1) by two independent routes involving 1-O-tri-n-butyl-stannyl and 1-O-triethylborate α-D-mannofuranosyl derivatives give α-D-mannofuranosyl /β-D-mannofuranoside (8a) after deprotection. β-D-Mannofuranosyl β-D-mannofuranosides can be prepared by reaction of 1 with the sodium triethylborate derivative of 2,3:5,6-di-O-isopropylidene-β-D-mannofuranose (11) and by reacting 1 with hexabutyldistannoxane. The latter approach allows the synthesis of β-D-mannofuranosyl β-D-mannofuranoside (8b) after total deprotection.

Photolysis of diphenylzirconocene and 2,3-bis(methylene)bicyclo[2.2.2]octane in toluene at -25 °C yields biphenyl and (2,3-bis(methylene)bicyclo[2.2.2]octane)zirconocene (lg) (67.5% isolated yield).1g exhibits dynamic NMR spectra indicating rapid alternation of diene faces coordinated to zirconium (ring-flip mechanism). This degenerate intramolecular rearrangement is characterized by an extremely low activation barrier (⊿G ≠ -131°C = 7.1 ± 0.3 kcal/mol). 1g crystallizes in space group P1̄with a = 7.215(1) Å, b = 9.654(1) Å, c = 11.831(1) Å, α = 94.97(1)°, β = 91.81(1)°, and γ = 103.22(1)°. The X-ray structure determination reveals a pronounced metal alkyl character of the (diene)ZrCp 2 moiety. Accordingly, 1g is easily reduced electrochemically to give a Zr(III) radical anion (7) observed by esr (g = 1.990; a(H) = 2.976 G; a(Zr) = 18.36 G).

The elementary processes involved in the polymerization of ethylene by soluble Ziegler catalysts of the type Cp 2 TiMeCl/AlMeCl 2 have been studied by 13 C NMR spectroscopy. Using 13 C-enriched ethylene, detailed information was obtained directly on the system in the course of the polymerization. No spectroscopic evidence was found for precoordination of the monomer. The development of the oligomer distribution, which could be followed spectroscopically, proves that the mechanism proposed by Olivé cannot be correct. These experiments show conclusively that the ethylene is inserted into the titanium-carbon bond.

Two routes have been studied to obtain the first hexadecker sandwich complexes 4. The reaction between the η 3 -allyl tetradecker 2b and the cobalt sandwich 3b in refluxing mesitylene leads to red-violet diamagnetic 4bb in 7% yield. Bis(allyl)nickel and the cyclopentadienylcobalt(2,3-dihydro-1,3-diborol) 3b form the tripledecker η 3 -allylnickel(μ, η 5 -dihydro-1,3-diborolyl)-cobalt(η 5 -cyclopentadienyl) 9b, which reacts at 160 °C with the bis(2,3-dihydro-1,3-diborol)nickel sandwich 10c to give 4bc (21%) and the tetradecker 7b (69%). The constitution of the new complexes is derived from NMR and mass spectra.

The ethylene molecule in the binuclear complex [bis(2-4η-phosphorinyl)nickel](η 2 -ethylene)-P,P′-nickel (1) is displaced by 1-alkenes in an equilibration reaction to give the corresponding (η 2 -1-alkene)nickel complexes 2-5. The NMR spectra of the octene complex 3 and the propene complex 6 are temperature dependent because of valence isomerization in the phosphorinyl group and rotation of the olefin. The binuclear structure is not maintained upon displacement of the ethylene by butadiene or isoprene. One nickel atom is displaced as the dodecatrienediylnickel complex 9 and the remaining bis(phosphorinyl)nickel fragment B reacts with insertion of the diene into one allyl-Ni bond to give 7 resp. 8. The molecular structure of 7 was determined by X-ray crystallography.

Aluminum can be dissolved by ethylene in the presence of aluminum trichloride to form primarily bis-(dichloro-aluminum)-ethanes (1) and (2) or in the presence of ethyl aluminum dichloride to form chloro-aluminum-ethyl-(dichloroaluminum)-ethane (3) and/or a tris-aluminum compound Cl 2 A1-C 2 H 4 -Al(Cl)-C 2 H 4 -Al(Cl)Et (4). 1-4 react further with olefins, with elimination of alkyl aluminum dichloride and/or dialkyl aluminum chloride, which are practically inert towards olefins. The C 2 H 4 -bridge is available to the growth and displacement reaction with olefins.

Bicyclic 1,2-diazepin-3-ones 1a-c, 2a, c are prepared by an iron carbonyl mediated reaction sequence from alkynes and cyclic 1,2-diazenes. The latter are first converted into hexacarbonyl diiron complexes which react with two molecules of an alkyne to afford tricyclic carbonyl iron compounds I -III. Oxidative degradation with bromine leads to these novel heterocycles whose structure is confirmed by an X-ray analysis of 1b.

The syntheses of 5a-c by coupling reactions of 3-tert-butoxy-1,6-methano[10]annulene with different aryldiazonium salts as well as their spectroscopic properties are described; an X-ray structure analysis of 5c is reported.

(Me 3 P) 2 Ni(C 2 H 4 ) (5) and (dmpe) 2 Ni2(C 2 H 4 ) 3 (6) react with various alkynes including ethyne (acetylene) and 1-alkynes to form the crystalline compounds (Me 3 P) 2 Ni(C 2 RR′), (dmpe)Ni(C 2 RR′), and (dmpe) 2 Ni 2 (C 2 R 2 ) 2 (R.R′ = H, Me, Ph). Structural assignments were made on the basis of 1 H, 13 C, and 31 P NMR data. The crystal and molecular structure of (dmpe)Ni(C 2 Ph 2 ) (17) has been determined by X-ray crystallography.

Reactions of (1,5-cyclooctadiene)(1,3,5-cyclooctatriene)ruthenium(0) with 3-butenoic acid in the presence of tertiary phosphines, PR 3 , afford η 3 -allylcarboxylatoruthenium(II) complexes formulated as (PR 3 ) 2 [xxx](1 (PR 3 = PPh 3 ), 2 (PR 3 = P(C 6 H 4 -p-OCH 3 ) 3 ). The reaction of 1 with carbon monoxide gives the complex (PPh 3 ) 2 (CO)[xxx] while reaction with Br 2 or I 2 leads to ring closure of the organic ligand to afford 2-butenolide.

Hydroxyl radicals from the radiolysis of N 2 O/O 2 (4:1 v/v)-saturated aqueous solutions have been reacted with acetate ions (10 -2 M). As measured by pulse radiolysis, the resulting ·CH 2 CO 2 - radicals react with oxygen yielding the corresponding peroxyl radicals, ·O 2 CH 2 CO 2 - (k = 1.7 x 10 9 M -1 s -1 ). These peroxyl radicals decay bimolecularly (2k = 1.5 x 10 8 M -1 s -1 ) giving rise to the products (G values in brackets) glyoxylic acid (2.7), glycolic acid (0.7), formaldehyde (1.4), carbon dioxide (1.4), organic hydroperoxide (0.7) and hydrogen peroxide (2.5). Oxygen is consumed with a G value of 5.3. Aided by data from pulse radiolysis it is concluded that the intermediate tetroxide formed upon the bimolecular decay breaks down by various routes to yield: (i) hydrogen peroxide and two molecules of glyoxylic acid (ca. 27%); (ii) oxygen, glycolic acid and glyoxylic acid (ca. 25%); (iii) hydrogen peroxide and two molecules of formaldehyde, carbon dioxide and OH - (25%). These reactions do not involve free radicals as intermediates; (iv) There is some O ⨪ 2 (G ≈ 0.5) formed in the decay of the peroxyl radicals, which is attributed to the decay of intermediate oxyl radicals (tetroxide → O 2 + 2 · OCH 2 CO 2 - ) by 1,2-H shift, oxygen addition and HO 2 · elimination, a reaction sequence which gives rise to glyoxylic acid (10%); (v) The reaction of O 2 ⨪ with the organic peroxyl radical yields the hydroperoxide (13%). Reaction (iii) is a novel peroxyl radical reaction.

The course of Aggregation of molecules of the title compound (1b) through different, spectroscopically discernible and chemically identifiable forms of associations could be followed by matrix isolation and thin film infrared and UV-visible spectroscopy. It was found that molecules of 1b in thin films form clusters which at low temperatures interact weakly, probably through the carbonyl oxygens of one and the boron atoms of the neighbouring molecules. On warming to 260 K this association gradually takes the form of more defined chelate bonds, probably with ordered three-dimensional intermolecular structures. Above this temperature spontaneous formation of crystallites of the previously reported ʻhotʼ and ʻcoldʼ modifications was observed. Studies with films of varying thickness indicate an interdependence of crystallite size and lattice energies.

Tl 2 TiS 4 is orthorhombic, space group Pbca, with a = 22.176(7), b = 9.484(4), c = 6.3977(9) Å, Z = 8. The crystal structure was solved by direct methods and refined to a conventional R of0.058 for 704 reflections with I ≥3σ(I). The crystal structure is characterized by infinite perthioanions, ∞ 1 -[TiS 4/2 (S2) 2- ], which are separated by Tl + -cations. The anion chains are built up by distorted octahedra which share two skew edges to form infinite cis-chains running along [001], The two unshared S-atoms of each octahedron are connected via a S -S-single bond of 2.10 Å length. The crystal structure is described as a mixed packing of TI-and S-atoms, composed of puckered TlS 2 -layers, in which the Ti-atoms occupy the octahedral interstices. The relationship of the ∞ 1 -[TiS 4 2- -]-chains to the anionic groups of Cs 2 TiS 3 is discussed.

Hydroboration of CS 2 with NaB 3 H 8 yields the new compound Na[CH 2 (BH 2 ) 5 S 4 ], isolated as the tri-dioxanat. The anion has the adamantane skeleton CB 5 S 4 .The crystal structure of the analog-ous compound (C 6 H 5 ) 4 P[CH 2 (BH 2 ) 5 S 4 ] was determined from diffractometer data and refined to R = 0.043. The tetragonal unit cell (space group P4/n) contains two formula units (a = b = 1351.7 pm; c = 790.0 pm).

Cyanides such as P(CN) 3 , As(CN) 3 , PhP(CN) 2 , Bu t As(CN) 2 and Ge(CN) 4 react with [(CF 3 ) 2 CS] 2 (1) by insertion of the carbon atom of the iso-nitrile isomer into the four-membered [CS] 2 ring to give compounds PR′ 3 (2), AsR′ 3 (3), FP(S)R′ 2 (4), PhP(S)R′2 (5), Bu t AsR′ 2 (6) and GeR′ 4 (7) respectively, where R′ is the novel heterocyclic ligand[xxx]. The crystal structures of 3 and 7 are reported.

Chromyl Chloride reacts with carboxylic acids [RCOOH where R = C 2 H 5 , n-C 3 H 7 , CH 2 CI, CHCl 2 and CCI 3 ] to give reduced chromium(III) carboxylates, [Cr 3 O(OOCR) 6 (H 2 O) 3 ]Cl. Magnetic susceptibility, UV-visible and IR measurements are all consistent with their trinuclear basic structures. Reactions of chromyl chloride with carboxylic acid anhydrides [(RCO) 2 O where R = CH 3 , C 2 H 5 and n-C 3 H 7 ] give dinuclear oxo-bridged complexes of the type, [Cr 2 O(OOOCR) 3 ]Cl. These compounds behave as non-electrolytes in polar organic solvents. IR spectra suggest the presence of bridging carboxylato groups containing Cr-O -Cr chains. Their low magnetic moment values suggest polymeric structures exhibiting antiferromagnetic coupling between Cr atoms.

The compounds [(C 6 H 5 ) 4 As] 2 TeCl 4 (1), [(C 2 H 5 ) 4 N] 2 TeBr 4 · CH 3 CN (2), and [(C 2 H 5 ) 4 N] 2 TeI 4 (3) were prepared by the reaction of Te, X 2 , and excess (C 2 H 5 ) 4 NX (X = Br, I) in acetonitrile solution or by heating of [(C 6 H 5 ) 4 As] 2 TeCl 6 , Te, and (C 6 H 5 ) 4 ASCl for several hours in the same solvent. The structures of 1-3 were determined from single crystal X-ray data. 1 crystallizes in the monoclinic space group P2 1 /n with a = 1061.8(2), b = 1614.2(3), c = 1341.7(3) pm, β = 94.21° and Z = 2; 2: tetragonal, P4/mmm, a = 1039.7(2), c = 690.5(1), Z = 1; 3: tetragonal, I4/mmm, a = 1061.7(2), c = 1342.8(4), Z = 2. In 1-3 Te(II) exhibits a square planar coordination. The Te -CI, Te -Br, and Te-I bond lengths were found to be 260.7 (mean), 275.3, and 298.5 pm, respectively.

The synthesis and the spectroscopic properties of the title compounds Cp(CO) 2 FeBiX 2 (with X = SC(S)NEt 2 and SC(S)OMe) are described. The crystal structure of Cp(CO) 2 FeBi[SC(S)NEt 2 ] 2 was investigated by an X-ray analysis.

In benzene solution the position of the 1 H NMR signals of sulfanes, H 2 Sn, strongly depends on the sulfur chain length and on the sulfane concentration. Under proper conditions all sulfanes in a mixture are characterized by well-resolved NMR signals showing a downfield shift with increasing length of the sulfur chain. The shift differences between the higher homologues ( n > 8 ) remain nearly constant, thus allowing the assignment of the signals up to H 2 S 35 and the determination of the complete sulfane distribution in crude oils. In sulfane mixtures without solvent as well as in CS 2 and CCl 4 solutions, however, H 2 S 8 shows the largest downfield shift. The signals of the higher sulfanes overlap in a narrow range at slightly higher field and cannot be characterized except for the CCl 4 solution where an assignment up to H 2 S 11 is possible. The chemical shifts are interpreted in terms of inter- and intramolecular hydrogen bondings. The upfield shift caused by benzene is attributed to the formation of H 2 S n · benzene complexes.

Selenium (1) and tellurium bis(trithiocarbonates) (2) were found to react with bromine and iodine to give the corresponding haloselenium (11) and halotellurium trithiocarbonates (7, 8). Reaction of 2 with excess of bromine give tribromotellurium trithiocarbonates (9).

N,N′-Diorganyl-oxalic acid diamides react with bis(diethylamino)dimethylsilane to yield the 1,3-Diaza-2-sila-cyclopentane-4,5-diones 1-9. The compounds were characterized by elemental analyses and spectroscopic data (NMR: 1 H, 13 C, 29 Si, 14 N; MS; IR).

Tetrafluorosilane and phenyltrifluorosilane react with the O-trimethylsilyl derivatives of N.N-disubstituted aminoethanols and with the N-trimethylsilyl derivative of N.N.N′-trimethylethylene diamine to give the corresponding monosubstituted fluorosilyl compounds in which, on the basis of 19 F NMR spectroscopic studies, intramolecular N -Si bonding raises the coordination number of silicon from four to five (i.e. λ 4 Si -> λ 5 Si). The low temperature 19 F NMR data suggest a trigonal-bipyramidal configuration at λ 5 Si with an axial N -Si coordinate bond.

The reactions of the glycinato, alaninato, or cyclo-leucinato chelate platinum complexes trans -[xxx] with nitrosyl salts NO + X - (X = BF 4 , PF 6 , SbF 6 ) in acetonitrile at -20 °C give the blue nitrosyl compounds {(0N)Pt [xxx] X·nCH 3 CN. Nitrosation at the amino group is not observed. The spectroscopic data of the nitrosyl complexes (IR, XPE) are reported. [xxx] + PF 6 - reacts with lithium halides or halogens in DMF to give the platinum (IV) complexes X 2 Pt(NH 2 CH 2 CO 2 ) 2 (X = CI, Br, I).

Charge-transfer Complexes, Nickel Dithiolenes. Methyl Viologen, X-Ray Anionic nickel dithiolenes form crystalline charge-transfer complexes with methyl viologen in its oxidized and reduced forms. X-ray analysis reveals that the planar acceptor methyl viologen interacts with the planar dithiolene donor via an expected parallel and a novel perpendicular arrangement.

Secundary amines - especially 2-aryloxyethyl-n-propylamines and 4-arylpiperazines were treated with ethyldichlorophosphate yielding ethylchlorophosphamides. Subsequent substitution of the chloroatom by morpholine derivatives, imidazole or triazole formed new ethylphosphorodiamidates with a broad-spectrum-fungicidal activity. Experimental details as well as the fungicidal properties are reported.

The amides of nicotinoylamino acids were prepared and alkylated to the quaternary salts 1f-n. The α-amino acid moiety in 1 is S configurated. The salts 1 cyclise under the influence of base to give the cyclopeptide-like substances 4, 5 and 7, with seven-or fourteen (sixteen, eighteen-) membered rings, respectively.

Seventeen analogs of the luteinizing hormone releasing hormone (LHRH) have been synthesized, bioassayed, and compared for antiovulatory activity (AOA) in rats. The emphasis of design was replacement of Tyr 5 of LHRH. Position 5 has not been extensively studied. [N-Ac-D-2-Nal 1 , D-pClPhe 2 , D-3-Pal 3 , D-Arg 6 , D-Ala 10 ]-LHRH was the baseline for new designs. Comparison of the AOA's of the 17 analogs with the baseline revealed the two peptides with Phe 5 and 3-Pal 5 had equivalent AOA's, and were the best of the 17, and about 45% more potent than the baseline. Analogs with pClPhe 5 , oClPhe 5 , α-MepClPhe 5 , 2-Nal 5 , Trp 5 , and His 5 were less potent than the Phe 5 -and 3-Pal 5 -analogs. Based on the Phe 5 -analog, eight other analogs were synthesized with changes in positions 1, 2, 3 and 7 and although none were better than the baseline, 5/8 showed 20-60% AOA's at 250 ng and revealed optimum positions for new designs.

Displacement of triflyl group by fluoride ion in benzyl 2,3-anhydro sugars leads with stereochemical inversion to fluorodeoxy sugars, providing a general method for the introduction of fluorine in the neighbourhood of oxirane ring in anhydro sugars. This procedure is mild, convenient, and does not experience difficulties which sometime are encountered in nucleophilic fluoride displacements in carbohydrate systems.

From the mycelium of the fungus Aspergillus quadrilineatus, a new pigment 7-methoxyaverufin has been isolated besides mannitol, sterigmatocystin, versicolorin, ergosterol, and averufin.