Miles T. Lakin

Crown thioether complexes of p-block elements: crystal and molecular structures of SbCl3·9s3 (9s3 = 1,4,7-trithiacyclononane) and 2SbCl3·18S6 (18S6 = 1,4,7,10,13,16-hexathiacyclooctadecane)

The first crown thioether complexes of SbIII and BiIII, as representative p-block elements, have been isolated, viz SbCl3·9S31, BiCl3·9S3·0.5 MeCN, SbCl3·15S5, 2SbCl3·18S6 2 and BiCl3·18S6; X-ray crystal structure determinations of 1 and 2 establish full participation of ligand S-donor sites in metal ⋯ sulphur bonding in each case.

Reactions of 1,4,7-trithiacyclononane, [9]aneS3, with early transition metal halides: synthesis and X-ray structure of {Fe([9]aneS3)2}[Sb2Cl8]

SummaryThe reactions of titanium(III) and (IV) chlorides with the crown thioether [9]aneS3 were investigated. [TiCl3- (MeCN)3] gives a purple 1:1 adduct with a proposed octahedral structure involving tridentate fac-attachment of the ligand. With [TiCl4(MeCN)2] the identity of the yellow 1∶1 adduct obtained is discussed in terms of a six-coordinate species with bidentate ligand chelation. The title compound was isolated from the reactions of [9]aneS3 with [TiCl3(MeCN)3] [SbCl6] (by accident) and iron filings/SbCl5 in MeCN solution and characterised crystallographically. The cation has two macrocyclic ligands coordinated facially to a six-coordinate Fe2+ ion; the anion comprises dimeric [(SbCl4)2] units linked together into a polymeric chain by weak halogen bridging.

Synthesis and molecular structure of the adduct trichlorobismuth–1,4,7,10,13,16-hexathiacyclooctadecane (1/1)

The reaction (1:1) of BiCl3 and [18]aneS6 in acetonitrile provides colourless crystals of the adduct BiCl3·[18]aneS6. An X-ray crystal structure determination has revealed a BiCl3 pyramidal unit bonded to all six sulfur atoms of the macrocyclic ring which adopts an unusual S-shaped conformation. The bismuth atom sits on a crystallographically imposed three-fold axis in a nine-co-ordinate [3:3:3] geometrical arrangement involving two sets of three sulfur atoms and the three chlorine atoms respectively. Crystals are cubic, space group Pa3 with Z= 8 and a= 16.381(5)A 1312 independent reflections were measured of which 825 with [I/σ(I) 2.0] were used in the final refinement, R= 0.044 (R′= 0.067), Bi–S 3.146(4) and 3.225(4)A, Bi–Cl 2.607(4)A and Cl–Bi–Cl 89.0(1)°.

Group 15–azamacrocyclic chemistry. Reactions of 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane (L) with MCl3(M = As or Sb): crystal and molecular structures of [H2L][As4O2Cl10] and [H2L][Sb2OCl6]

The reactions of MCl3(M = As or Sb) and 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane (tetramethylcyclam, L) have been studied under controlled hydrolysis conditions as a route to anionic bridging chlorooxo arsenic- or antimony-(III) species. With M = As, the ionic complex [H2L][As4O2Cl10]1 has been isolated and characterised by an X-ray crystal-structure determination. The diprotonated tetraazamacrocyclic dications adopt an endodentate geometry with all four N–CH3 groups positioned on the same side of the ring in an R,S,R,S[trans-(I)] configuration. The two protons are bonded to alternate nitrogen atoms and are involved in hydrogen bonding within the ring cavity. Each arsenic(III) centre of the tetranuclear µ4-chloro-µ-oxo complex anion [As4O2Cl10]2– shows ψ-octahedral co-ordination geometry with an associated stereochemically active lone pair. With M = Sb, the ionic complex [H2L][Sb2OCl6]2 has been isolated and its structure determined. The macrocyclic dications are again in an endodentate conformation with intramolecular hydrogen bonding across the ring cavity but in this case the N–CH3 groups are directed in pairs to opposite sides of the ring in an R,R,S,S[trans-(III)] configuration. The antimony atoms of the binuclear µ-chloro-µ-oxo complex anion [Sb2OCl6]2– have ψ-octahedral geometry with a stereochemically active lone pair. Both anions contain similar Cl2MOMCl2 primary units (mean As–Cl 2.21, Sb–Cl 2.43, As–O 1.77, Sb–O 1.94 A) with Cl– ions forming secondary M ⋯ Cl interactions (mean As ⋯ Cl 3.08, Sb ⋯ Cl 2.89 A).

Heteroleptic metallacyclic potassium organodiamido zincate complex. Synthesis and structure of polymeric {[K(thf)][MeZn(ButNCHCHNBut)]}n

The reaction of the C–C coupled dimer of two neutral organozinc radicals, [MeZn(ButNCHCH(NBut)CH(NBut)CHNBut)ZnMe]1, with potassium in tetrahydrofuran affords the metallacyclic neteroleptic potassium organodiamido zincate K[MeZn(ButNCHCHNBut)]2 quantitatively, which exists in the solid state (X-ray crystallography) as a linear polymer formed by alternating potassium cations and organodiamidozincate anions.

Crown ether complexation of scandium(III), yttrium(III) and lanthanum(III) halides. Synthesis and spectroscopic characterisation of anhydrous cationic metal-oxacrown species and crystal structure of a scandium benzocrown

Halide abstraction reactions of MCl3(M = Sc, Y or La) with SbCl5 in the presence of a crown ether provided a series of anhydrous cationic MIII-crown compounds of the types [MCl2(crown)][SbCl6][M = Sc, crown = 1, 4, 7, 10, 13, 16- hexaoxacyclooctadecane (18-crown-6), 2,3,5,6,8,9,11,12-octahydro-1,4,7,10,13-benzopentaoxacyclopentadecine (benzo-15-crown-5), or 1,4,7,10,13-pentaoxacyclo- pentadecane (15-crown-5)], [ScCl2(12-crown-4)(MeCN)][SbCl6](12-crown-4 =1,4,7,10-tetraoxacyclododecane),[M(18-crown-6)(MeCN)3][SbCl6]3(M = Y or La) and [M(12-crown-4)(MeCN)5]-[SbCl6]3(M = Y or La). Analytical and spectroscopic (1H and 13C NMR) characterisation of these compounds supports their formulation as hexachloroantimonate(v) salts. The structure of [ScCl2(benzo-15-crown-5)][SbCl6] has been determined by X-ray diffraction. Crystals are orthorhombic, space group Pbca with a= 17.015(10), b= 13.296(8), c= 22.236(12)A and Z= 8. The cation has a threaded structure with an essentially linear ScCl2+ unit [Sc–Cl (mean) 2.395 A, Cl–Sc–Cl 175.5°]. All the oxygen atoms of the oxacrown ligand are coplanar and are bonded to the central scandium atom, Sc–O 2.166(4)–2.223(4)A, (mean) 2.188 A with the benzene ring titled out of this plane at an angle of 24.9°. The resulting geometry of the seven-co-ordinate scandium atom is pentagonal bipyramidal.

Crystal and molecular structure of 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane: Energy and structural relationships for this tetraazamacrocycle in its neutral and protonated forms

AbstractThe X-ray crystal structure of 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane has been determined. The neutral ligand crystallises in the triclinic space groupP

Unusual crown ether encapsulation of a chloroscandium(III) cation. Structure of threaded [ScCl2(18-crown-6)][SbCl6]

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