John J. Daly

Reaction of iodocarbonylrhodium ions with methyl iodide. Structure of the rhodium acetyl complex: [Me3PhN+]2[Rh2I6(MeCO)2(CO)2]2−

A rhodium acetyl complex [Me 3 PhN + ] 2 [Rh 2 I 6 (MeCO) 2 (CO) 2 ] 2− has been prepared and structure determined by X-ray diffraction: the RhC (acetyl) bond length is 2.062(23) A and the dimeric anion is held together by RhIRh bridges with unequal RhI bond lengths.

Structure of Phosphobenzene

WE have already shown that of the polyphosphines of formula (C6H5P)n and melting points (A) 149–150°, (B) 190°, (C) 252°–256°, (D) 260°–285°, compound A is a five-membered ring compound in the solid state1.

Crystal and molecular structure of cis-diphenylbis-(2,2′-bipyridyl)-chromium(III) iodide

Crystals of the title compound are monoclinic, space group C2/c, with cell dimensions a= 11·034, b= 16·021, c= 16·183 A, β= 103° 31′, Z= 4. The final R for 2227 counter data refined by a block-diagonal least-squares method is 0·054. The organometallic cation, which has the cis-octahedral configuration, possesses a crystallographic two-fold symmetry axis. The chromium–carbon σ bond length [2·087(4)A] is no different from the corresponding length in the cis-[(2-methoxyphenyl)2Cr(bipy)2]+(bipy = 2,2′-bipyridyl) cation. The chromium–nitrogen bonds which are not related by the two-fold symmetry axis have different lengths; those trans to nitrogen [2·087(4)] being shorter than those trans to carbon [2·147 (4)A].

Reaction of trifluoroacetonitrile with π-allylic-iridium complexes; the crystal structure of an iridium(I) six-membered ring chelate complex

[Ir(π-2-Me-C3H4)(CO)(PPh3)2] reacts with CF3CN to afford an iridium(I) six-membered chelated complex, identified by X-ray crystallography; whereas, with [Ir(π-1-MeC3H4)(CO)(PPh3)2] C4H6 is displaced and a five-membered ring system is formed from two CF3CN molecules joined head to tail.

Crystal and molecular structure of bis[(trimethylsilyl)methyl]bis-(2,2′-bipyridyl)chromium(III) iodide

Dark red crystals of the title compound are monoclinic, space group P21/c, with cell dimensions a= 18·139(15), b= 9·611(8), c= 18·919(15)A, β= 104·27(17)°, Z= 4. The structure was solved by direct methods. The final R for 3758 counter data refined by block-diagonal least-squares is 0·057. The cis-octahedral organometallic cation has an approximate two-fold symmetry axis. The CrIII–C(sp3)σ-bond length [2·107(12)A] is the same as that found in two aryl analogues. The Cr–N bond trans to carbon is 2·156(7) while that trans to nitrogen is 2·103(7)A, these differences are discussed in terms of σ- and π-bonding effects.

Crystal and molecular structure of 3,7-dihydro-1,1,3,3,5,5,7,7-octamethyl-1H,5H-benzo[1,2-c:4,5-c′]bis[1,2,5]oxadisilole

Crystals of the title compound are monoclinic, space group P21/c with a= 10·669(9), b= 9·159(8), c= 11·518(10)A, β= 115·2(1)°. Diffractometer data for 1401 planes were refined by least squares to R 0·045. The nature of the molecule was unknown and the structure was determined by direct methods. Bond lengths in the oxadisilole ring, which has approximate C2v, symmetry, are: C–C 1·411, Si–C 1·882, and Si–O 1·647 A.

Crystal and molecular structure of [iminobis(ethyleneoxy)]diphenylsilane: a five-co-ordinate silicon compound

Crystals of the title compound (V) are orthorhombic, space group P212121, with a= 9·056(7), b= 11·904(10), c= 14·175(13)A. Monochromated diffractometer data for 1341 planes were used to solve the structure by Patterson and Fourier methods and were refined by least squares to a final R of 0·070. The formal eight-membered ring is bridged by a silicon–nitrogen bond of 2·301(6)A, and the silicon atom adopts a trigonal bipyramidal geometry of approximate symmetry Cs.

Reactions of co-ordinated ligands. Part VI. The addition of hexafluoropropene, trifluoroethylene, and chlorotrifluoroethylene to tricarbonyl(diene)iron or ruthenium complexes and to tricarbonyl(o-styryldiphenylphosphine)iron

U.v. irradiation of a solution of hexafluoropropene and tricarbonyl(buta-1,3-diene)iron, tricarbonyl(isoprene)iron, tricarbonyl(2,3-dimethylbuta-1,3-diene)iron, and tricarbonyl(cyclohexa-1,3-diene)ruthenium affords 1 : 1 π-allylic adducts, in which the fluoro-olefin links the iron atoms and the hydrocarbon chain. An X-ray crystal-structure determination of the isoprene adduct established the direction of addition as FeCF(CF3)CF2, and comparison of n.m.r. data suggests the same direction of addition for the other systems studied. Reaction of tricarbonyl(cyclohexa-1,3-diene)iron affords a 1 : 1 adduct formulated as an endo-CF2·CHF(CF3) substituted tricarbonyl(cyclohexa-1,3-diene)iron complex, a π-allylic complex in which an additional hexafluoropropene links the C6 ring and iron atom, and a third product a tetracarbonylferracyclopentane. Related reactions of tricarbonyl(tricyclo[4.2.0]octa-1,3-diene)iron and tricarbonyl(cyclo-octa-1,3-diene)iron are reported. Similar oxidative-linking reactions occur between chlorotrifluoroethylene and tricarbonyl(2,3-dimethylbuta-1,3-diene)iron, and trifluoroethylene with tricarbonyl(cyclohexa-1,3-diene or bicyclo[4.2.0]octa-1,3-diene)iron. The reaction of tricarbonyl(o-styryldiphenylphosphine)iron with hexafluoropropene, chlorotrifluoroethylene, and trifluoroethyleno also leads to 1 : 1 adducts, formulated as ferracyclopentanes. The mechanism of formation of these compounds is discussed.

Crystal and molecular structure of tetra(methylsilicon) hexasulphide (1,3,5,7-tetramethyl-2,4,6,8,9,10-hexathia-1,3,5,7-tetrasila-adamantane)

The crystal structure of the title compound has been determined by single-crystal X-ray diffraction methods. Crystals are monoclinic, space group C2/c, with a= 9.382(10), b= 16.513(20), c= 10.584(11)A, β= 107° 10(10)′, and Z= 4. The structure was solved by direct methods and refined by block-diagonal least-squares techniques to R 4.4% for 1 284 independent reflections measured by diffractometer. The molecule exhibits the crystallographically required C2 symmetry and approximates closely to Td(3m) symmetry like the corresponding Ge and Sn compounds. Mean molecular parameters in the adamantane-type structure are: Si–S 2.129, Si–C 1.836 A; Si–S–Si 104.6, S–Si–S 111.8, and S–Si–C 107.0°. The Si valence angles show a smaller distortion from the tetrahedral value than do those at S. The molecular conformation and crystal packing are compared with that in other hexathia-adamantanes.

Crystal and molecular structure of 2,cis-4,trans-6-triphenyl-2,4,6-trithioxo-1,3,5,2,4,6-trioxatriphosphorinan

Crystals of the title compound (Ia) are monoclinic, space group P21/c with a= 12·257(10), b= 9·299(7), c= 21·027(17)A, β= 119·77(17)°. The structure was solved by direct methods. Diffractometer data for 3148 planes were refined by block-diagonal least-squares to R 0·043. The boat-like six-membered ring approximates closely to the symmetry m(C8): five of the constituent atoms are coplanar to within 0·04 A while the sixth, an oxygen atom, is displaced 0·32 A from this plane. Two phenyl groups and one sulphur atom lie on one side of the heterocyclic ring and the other phenyl group and two sulphur atoms on the other side. The mean lengths of the chemically equivalent bonds are: P–C 1·779(4), PS 1·896(2), P–O 1·613(3), and CC 1·383(7)A.