Kenneth J. Haller

Interconversions of .eta.5-cyclopentadienyl, .eta.1-cyclopentadienyl, and ionic ".eta.0"-cyclopentadienyl rhenium compounds - x-ray crystal structure of tetrakis(trimethylphosphine)methylnitrosylrhenium cyclopentadienide

The reaction of (eta/sup 5/-C/sub 5/H/sub 5/)Re(NO)(CH/sub 3/)(PMe/sub 3/) and PMe/sub 3/ (trimethylphosphine) produced (eta/sup 1/C/sub 5/H/sub 5/)Re(NO)(CH/sub 3/)(PMe/sub 3/)/sub 3/. The reaction is reversible with K/sub eq/ = 0.4 M/sup -2/ at 4/sup 0/C in THF-d/sub 8/. Upon heating at 48/sup 0/C in THF in the presence of high concentrations of PMe/sub 3/, the equilibrium mixture was converted to (Re(NO)(CH/sub 3/)(PMe/sub 3/)/sub 4/)/sup +/(C/sub 5/H/sub 5/)/sup -/, which precipitates from solution. The structure was determined by X-ray crystallography: monoclinic space group P2/sub 1//c, with unit cell constants a = 12.893 (2) A, b = 13.622 (2) A, c = 15.068 (2) A, ..beta.. = 97.47 (2)/sup 0/, and Z = 4. 20 references, 2 figures, 2 tables.La reaction de (η 5 −C 5 H 5 )Re(NO)(CH 3 )(PMe 3 ) et PMe 3 donne (η 1 −C 5 H 5 ) Re(NO)(CH 3 )(PMe 3 ) 3 . Par chauffage a 48°C dans THF, le melange des 2 complexes est converti en [Re(NO)(CH 3 )(PMe 3 ) 4 ] 4 [C 5 H 5 ] − , dont on etudie la structure cristalline

Synthesis and crystal structures of two diruthenium polysulphide complexes

Abstract The reaction between Ru(SPh)(PPh3){P(OMe)3}(η-C5H5) and sulphur, in acetonitrile, affords two diruthenium polysulphide complexes, Ru2{P(OMe)3}2(η-C5H5)2S4(I) and Ru2{P(OMe)3}2(η-C5H5)2S6(II). The latter could be converted to the former by reaction with PPh3. Structures of both blue-black, crystalline species were determined by single crystal X-ray diffraction methods. The former contained a six-membered, non-planar ring (cyclohexane chair structure) consisting of the two metal atoms and four sulphurs with the metals in the 1- and 4-positions, while the latter contained a Ru2S6 eight-membered ring, with metal atoms in the 1- and 5-positions and a long bond between two sulphurs across this ring, a structure not unlike that of [S8]2+. Comments are presented on the unusual bonding in the Ru2Sn rings in these two species.

Synthesis, structure, and photochemistry of a rhenium(I) enolate complex

Abstract The rhenium(I) enolate complex fac-(CO)3(P(CH3)3)2Re(OC(CH3)C5H4) (4 was prepared from the reaction of (η5-C5H4C(O)CH3)Re(CO)3 (3) with P(CH3)3. Compound 4 was characterized structurally in the solid state by X-ray crystallography and in solution by IR and 1H, 13C, and 31P NMR spectroscopy. Photolysis of 4 at 337 nm in CH2Cl2 solution cleaves the ReO bond: smooth conversionto fac-(CO)3(P(CH3)3)2ReCl (5) is observed with a quantum yield of 0.04.

Crystal structures of two syn bent tetraalkylhydrazines, their radical cations, and a dication

Abstract The crystal structures of 2,7-diazatetracyclo[6.2.2.23,6.02.7]tetradec-4-ene, 2, its cation radical nitrate salt 2+, NO3-, 2,7-diazatetracyclo[6.2.2.23,6.03,7]tetradecane, 3, its dication dihexafluorophosphate salt 32+(PF6-)2, and a low quality structure of the monocation radical tosylate salt of 3 are reported and compared with MNDO calculations of these structures. Cations 2+ and 3+ are found to be significantly syn bent at nitrogen, and the dication 32+ has a longer N-N distance than its azo analogue, 2,3-diazabicyclo [2.2.2]oct-2-ene (11).

The X-ray crystal structure of tetramesityldisilene

Tetramesityldisilene adopts a trans-bent geometry in the crystal, with an SiSi bond length of 216.0 pm; two of the cis aromatic rings are only slightly twisted relative to the approximate plane of the two silicon and four neighbouring carbon atoms, while the other two rings are nearly perpendicular to this plane.

The use of N-benzenethiophthalimide as a reagent in organometallic syntheses: benzenethiolato- and N-phthalimidometal carbonyl complexes

The reaction between PPN[CpW(CO) 3 ](PPN + = Ph 3 PNPPh 3 + ) and N -benzenethiophthalimide (PhSphth) gives CpW(CO) 3 SPh and PPN[phth], and the organometallic compound was isolated in high yield. Contrasting results occur using PPN[Mn(CO) 5 ] and PPN[CpMo(CO) 3 ]. Although the expected benzenethiolatometal complexes are detected as initial products, these species react further with the phthalimide anion (phth − ) to give phthalimidometal complexes. From a reaction using PPN[Mn(CO) 5 ] and PhSphth in a ratio one can isolate PPN[Mn(CO) 4 (phth) 2 ] in good yield. There is some evidence that PPN [Mn(CO) 4 (SPh)(phth)] is also an intermediate in this reaction. In a ratio, these reagents give a mixture of PPN[Mn(CO) 4 (phth) 2 ] and PPN[Mn 2 (μ-SPh) 3 (CO) 6 ]. Formation of PPN[Mn(CO) 4 (phth) 2 ] can also be accomplished by more traditional reactions between PPN[phth] and either MnBr(CO) 5 or Mn 2 (μ-Br) 2 (CO) 8 . A single crystal X-ray diffraction study provides the structure of PPN[Mn(CO) 4 (phth) 2 ]. The reaction between PPN[CpMo(CO) 3 ] and PhSphth gives CpMo(Co) 3 SPh which is rapidly converted to a species believed to be PPN[CpMo(CO) 2 (phth) 2 ]. Isolation of this unstable compound was not accomplished.

Conformational studies and crystal structures of cis- and trans-1,4-bis(trimethylsilyl)hexamethyl-1,4-disilacyclohexa-2,5-diene

Abstract The geometries of cis -and trans -bis(1,4-trimethylsilyl)-1,2,3,4,5,6-hexamethyl-1,4-disilacyclohexa-2,5-diene have been studied by 13 C NMR and X-ray single crystal analysis. The trans isomer adopts a nearly planar conformation with a slight deformation toward a chair form which is most likely caused by steric interactions between the vinyl-methyl substituents and the groups on the ring silicon atoms. Unlike the trans isomer and the other previously reported disilacyclohexadienes, the cis isomer resides in a slightly twisted boat conformation. The two bulky trimethylsilyl substituents are located in pseudo-axial positions. This finding is in accord with recent calculations which predict the bulky 1,4 substituents should occupy axial positions in the cyclohexa-2,5-dienyl ring system.

Oxidative ring opening and rearrangement of an anthroquinocyclopropene. Molecular structure of a novel spiro-3-furanone

Abstract Reaction of anthraquinone 1 with diethyl dithiophosphate led to oxidative ring opening with the formation of spiro-3-furanone 3; subsequent oxidation of 3 with alkaline potassium ferricyanide gave a 4,5-bis(quino)-3-furanone, 4, whose structure was established by x-ray crystallography.

The synthesis and molecular structure of a disilacyclopropanimine

Tetra(2,6-dimethylphenyl)disilene reacts with (2,6-dimethylphenyl)isocyanide in benzene solution at room temperature to form disilacyclopropanimine (1), a bright red crystalline compound with λmax=; 510nm, whose structure was established by X-ray crystallography.

1,8,15,22,30,34-hexaoxa-29,35-dioxo[8.8.7](1,4,2)cyclopha-3,5,17,19-tetrayne and 1,8,15,22,30,34-hexaoxa-29,35-dioxo[8.8.7](1,4,2)cyclophane, models for conformationally-defined hosts

Abstract The title molecules exhibit minimum barriers of 24-26 kcal mol -1 to ring inversion; an X-ray crystal structure of the saturated phane shows the aromatic rings to lie in contact and stacked.