Ian B. Gorrell

Preparation and crystal structures of aluminium hydride adducts with tetrahydrofuran [AlH3·OC4H8]2 and AlH3·2OC4H8

Crystalline adducts [AIH3·OC4H8]2 and AIH3·2OC4H8[OC4H8= tetrahydrofuran (THF)] can be obtained from solutions of alane in THF and from the reaction of [Me3N·AIH3]2 with THF.

Preparation, crystal structure and extended-Hückel molecular-orbital study of the free-radical complex [Ni2(cp)2(PhCN2S2)](cp =η-C5H5)

Dimeric 4-phenyl-1,2,3,5-dithiadiazole (PhCN2S2)2 reacted with [{Ni(cp)(CO)}2] to give [Ni2(cp)2-(PhCN2S2)](cp =η-C5H5). The X-ray structure was found to be based on an Ni2S2 tetrahedral core with Ni–Ni 2.441(1), S ⋯ S 2.905(2) and average Ni–S 2.172(1)A. The relatively short nickel–nickel distance, indicating formally 19-electron nickel centres, and other structural features are discussed in relation to similar dinickel complexes and by means of extended-Huckel calculations.

The 4-phenyl-1,2,3,5-dithiadiazole complex [Fe2(CO)6(PhCN2S2)]: its preparation, crystal structure, and an extended-Hückel molecular-orbital study of the bonding

The dithiadiazole (PhCN2S2)2 reacts with [Fe2(CO)9] or [Fe3(CO)12] to give [Fe2(CO)6(PhCN2S2)]. The butterfly structure of this complex is similar to that of other Fe2S2 complexes, with Fe–Fe 2.533(2), S–S 2.930(2), and mean Fe–S 2.225(10)A. Extended-Huckel molecular-orbital (m.o.) calculations, supported by X-ray structural data, indicate that the unpaired electron (in an antibonding m.o. largely concentrated on the dithiadiazole ligand) is responsible for the very weak S ⋯ S and intermolecular N ⋯ N interactions.

Tris(3-tert-butylpyrazolyl)hydroborato zinc hydride: synthesis, structure and reactivity of a monomeric zinc hydride derivative

The monomeric zinc hydride derivative {η3-HB(3-Butpz)3}ZnH has been synthesized by the reaction of ZnH2 with Tl{η3-HB(3-Butpz)3} and its reactivity investigated.

Reactions of S3N2Cl2 and (NSCl)3 with a new silylcyanamide reagent (Me3Si)2N·CN: synthesis and X-ray crystal structure of SNSNS: N·CN and bicyclic CCLS3N5

The new reagent bis(trimethylsilyl)cyanamide reacts with S3N2Cl2 and (NSCl)3 to give [graphic omitted]·NCN and CClS3N5 in good yields; the crystal structures of both products have been determined.

4-Phenyl-1,2,3,5-dithiadiazolyl: a novel coupling reagent for the formation of E–E bonds (E = C, P, Si)

[Ph[graphic omittted]]2 reacts under mild conditions with molecules containing bonds of the types P–Cl (Ph2PCl and PhPCl2), Si–Br (Me3SiBr) and activated C–Cl or C–Br (ortho-chloranil or MeCOBr) with the formation of [Ph[graphic omittted]]X (X = Cl or Br) and the corresponding E–E (E = P, Si or C) bonded compounds; the application of dithiadiazolyl radicals as coupling reagents is discussed in the context of the strength of the E–Hal bond.

Tris(pyrazolyl)hydroboratozinc alkyl derivatives: direct comparison of the reactivity of Zn-C and Mg-C bonds

The monoalkyl zinc derivatives [η3-HB(3-Butpz)3]ZnR (3-Butpz = 3-C3N2ButH2; R = Me, Et) have been prepared by metathesis of R2Zn with Tl[HB(3-Butpz)3], and their reactivity compared with that of the isostructural magnesium alkyl derivatives.

Preparation and structures of some new pyrrolidinido- and piperidinidoalanes and -aluminates

Alane and lithium tetrahydroaluminate each reacted with an excess of pyrrolidine or piperidine in tetrahydrofuran (thf) to give the new dinuclear compounds {Al[[graphic omitted]H2]3}2[n= 3 (from pyrrolidine)1 or 4 (from piperidine)2] and L2Li[µ-[graphic omitted]H2]2Al[[graphic omitted]H2]2[n= 3, L = thf 3 or H[graphic omitted]H24;n= 4, L = thf 5]. The compounds were characterised by elemental analysis, multinuclear NMR spectroscopy, mass spectrometry and, for 1, 4 and 5, X-ray crystallography. In 1, which contains an Al2N2 ring, average distances are Al–N(terminal) 1.797(2) and Al–N(bridging) 1.963(2)A. Exocyclic N–Al–N angles are in the range 112.6–114.4°, the endocyclic N–Al–N angle is 86.69(9)° and Al–N–Al is 93.31(9)°. The sums of the angles at the terminal nitrogens are close to 360°. In 4, which contains an LiN2Al ring, distances are Al–N(terminal) 1.824(8), Al–N(bridging) 1.880(7), Li–N(terminal) 2.035(20) and Li–N(bridging) 2.149(20)A. The sums of the angles at terminal nitrogens are 349.1 and 355.4°. Ring angles are N–Al–N 100.0(3), Al–N–Li 82.0(4) and N–Li–N 84.2(5)°. In 5 average distances are Al–N(terminal) 1.828(3), Al–N(bridging) 1.895(3), Li–O 1.987(6)A and Li–N(bridging) 2.135(6)A. The sums of the angles at terminal nitrogens are 358.1 and 357.4°. Ring angles are N–Al–N 100.69(13), Al–N–Li 84.0(2) and N–Li–N 86.2(2)°. Exchange between bridging and terminal amido groups is slow on the NMR time-scale at 250 MHz in 1 and 2 but fast in 3–5. Separate signals for axial and equatorial protons are observed from cooled samples of 2 and 5.