Paul R. Meehan

Chain, sheet and framework structures in the adducts of phenylphosphonic acid with 4,4'-bipyridyl (1/1), piperazine (2/1) and 1,4-diazabicyclo[2.2.2]octane (2/1)

Phenylphosphonic acid–4,4′-bipyridyl (1/1), (1), C6H7O3P.C10H8N2, triclinic, P1¯, a = 6.9026 (8), b = 9.7086 (9), c = 12.201 (2) A, α = 77.138 (9), β = 74.345 (10), γ = 75.477 (8)°, with Z = 2, is a salt, C10H9N2+.[C6H5PO2(OH)]−, containing singly protonated 4,4′-bipyridyl cations: the cations and anions are linked by N—H⋯O and C—H⋯O hydrogen bonds in an R^{2}_{2}(7) motif and these aggregates are linked into centrosymmetric R^{2}_{2}(8) dimers by O—H⋯O hydrogen bonds; the dimer units are linked into chains by C—H⋯O hydrogen bonds. Phenylphosphonic acid–piperazine (2/1), (C6H7O3P)2.C4H10N2 (2), monoclinic, P21/n, a = 6.0042 (9), b = 19.746 (3), c = 8.651 (2) A, β = 105.63 (2)°, with Z = 2, is a salt, C4H12N22+. [{C6H5PO2(OH)}−]2, containing doubly protonated piperazine: the anions are linked by O—H⋯O hydrogen bonds into centrosymmetric R^{2}_{2}(8) dimers and these dimers are linked to the centrosymmetric cations by N—H⋯O hydrogen bonds: each cation is hydrogen-bonded to four different anion dimers and each anion dimer is hydrogen-bonded to four different cations; the overall structure consists of two-dimensional sheets built from R^{4}_{6}(16) and R^{4}_{4}(18) rings. Phenylphosphonic acid–1,4-diazabicyclo[2.2.2]octane (2/1), (3), (C6H7O3P)2.C6H12N2, monoclinic, P21/n, a = 6.3607 (3), b = 21.8300 (11), c = 14.5965 (9) A, β = 92.558 (6)°, with Z = 4, is a salt in which one nitrogen of the diamine is fully protonated and the other is partially protonated: the anionic components are linked into C(4) chains by O—H⋯O hydrogen bonds, and these chains are cross-linked via the diamines by means of N—H⋯O and O—H⋯N hydrogen bonds. The resulting sheets built from R^{8}_{8}(34) rings are linked by C—H⋯O hydrogen bonds into a three-dimensional framework.

Crystal Engineering Using Bis- and Tris-phenols. Adducts with 1,4,8,11-Tetraazacyclotetradecane (Cyclam): Isolated Ladders in the Adduct with 4,4'-Thiodiphenol, Tethered Ladders in the Adduct with 4,4'-Sulfonyldiphenol and Two Interwoven Three-Dimensional Networks in the Adduct with 1,1,1-Tris(4-hydroxyphenyl)ethane

The structure of 4,4′-thiodiphenol–1,4,8,11-tetraazacyclotetradecane (2/1), (C12H10O2S)2.C10H24N4 (1), monoclinic, P21/c, a = 11.1602 (12), b = 10.8084 (12), c = 14.001 (2) A, β = 103.127 (10)°, with Z = 2, contains phenolate anions [HOC6H4SC6H4O]− and diprotonated cyclam cations [C10H26N4]2+: these cations have the centrosymmetric trans-III conformation and the two additional protons are contained within the N4 cavity of the macrocycle, held by three-centre hydrogen bonds. The phenolate anions form chains, held together by O—H⋯O hydrogen bonds, and pairs of these chains are cross-linked into ladders by the [cyclamH2]2+ cations by means of N—H⋯O hydrogen bonds. The structure of 4,4′-sulfonyldiphenol–1,4,8,11-tetraazacyclotetradecane (2/1), (C12H10O4S)2.C10H24N4 (2), triclinic, P1¯, a = 10.9345 (10), b = 11.0060 (10), c = 14.350 (2) A, α = 79.532 (10), β = 86.739 (10), γ = 87.471 (10)°, with Z = 2, contains phenolate anions [HOC6H4SO2C6H4O]− and cyclam dications [C10H26N4]2+: the phenolate anions are linked into antiparallel chains, cross-linked by the cyclam cations. There are two distinct types of ladder in the structure running along (0, y, 0) and (1\over2, y, 1\over2), respectively, and these bundled ladders are tied together by C—H⋯O hydrogen bonds to form a continuous three-dimensional array. In 1,1,1-tris(4-hydroxyphenyl)ethane–1,4,8,11-tetraazacyclotetradecane–methanol (2/1/1), (C20H18O3)2.C10H24N4.CH4O (3), triclinic, P1¯, a = 8.2208 (11), b = 16.245 (2), c = 17.337 (2) A, α = 81.694 (13), β = 89.656 (14), γ = 86.468 (12)°, with Z = 2, the structure contains centrosymmetric diprotonated cyclam cations of precisely the same type as found in (1), phenolate anions [(HOC6H4)2C(CH3)C6H4O]− and neutral methanol molecules. The molecular components are linked together by nine different types of hydrogen bond, five of O—H⋯O type and four of N—H⋯O type, to form chains running in the [001], [010] (two sets), [211] and [211¯] directions. The combination of these chain motifs generates two independent three-dimensional networks which are fully interwoven, but not bonded to one another.

STRUCTURAL CHEMISTRY OF SC(III) : AN OVERVIEW

Abstract Structural aspects of the chemistry of organometallic/coordination compounds of scandium(III) are reviewed. Individual compounds are classified and discussed in terms of coordination number and associated metal geometry through the range CN=3–9. The present review provides an exhaustive literature coverage 1926–1998 (April).

Crystal engineering using polyphenols. Host-guest behaviour of planar ribbons in C-methylcalix[4]resorcinarene-4,4′-trimethylenedipyridine-methanol (1/2/0.5), and capture of 2,2′-bipyridyl molecules by paired calixarene bowls in C-methylcalix[4]-resorcinarene-2,2′-bipyridyl-methanol-water (1/1/1/1.16)

Co-crystallisation of the rccc isomer of C-methylcalix[4]resorcinarene 1 with 4,4′-trimethylenedipyridine from methanol yields a solvated 1:2 adduct 2 in which the resorcinarene acts as a quadruple donor and the dipyridines both act as double acceptors, in O-H‥N hydrogen bonds. The supramolecular structure consists of linear and nearly planar ribbons with the bowls of the resorcinarene units in one ribbon acting as hosts towards the -(CH 2 ) 3 - spacer units of a neighbouring ribbon, acting as guests. Co-crystallisation of the same resorcinarene 1 with 2,2′-bipyridyl yields a doubly solvated 1:1 adduct resorcinarene-2,2′-bipyridyl-methanol-water (1/1/1/1.16) 3. The resorcinarene, methanol and water molecules combine by means of multiple O-H‥O hydrogen bonds to form paired, essentially-planar two-dimensional nets in which centrosymmetric pairs of resorcinarene bowls act as self-assembled carcerands to form large cavities in which pairs of 2,2′-bipyridyl molecules are held by a combination of O-H‥N and C-H‥O hydrogen bonds.

Controlled hydrolysis reactions of the Group 15 element–azamacrocyclic complexes MCl3L (M = As, Sb or Bi; L = 1,4,7-trimethyl-1,4,7-triazacyclononane). Formation and crystal structures of [AsCl2L][As2OCl5], [H2L]2[Sb2OCl6]Cl2, [HL]I and [H2L]2[Sb2Cl9]Cl·MeCN·H2O

Reactions of MCl3(M = As, Sb or Bi) and 1,4,7-trimethyl-1,4,7-triazacyclononane (Me3[9]aneN3= L) gave the respective 1 : 1 adducts as white-yellow microcrystalline solids which were characterised by microanalytical and spectroscopic (IR and 1H NMR) data. Addition of water to AsCl3L under controlled stoichiometry in acetonitrile solution led to the formation of the white crystalline salt [AsCl2L][As2OCl5]1. A crystal structure determination revealed the cation as five-co-ordinate with ψ-octahedral metal geometry featuring a cis-AsCl2+ unit co-ordinated to the three donor nitrogen atoms of the ligand (fac) and a stereochemically active lone pair occupying the sixth site [As–Cl 2.462(7), 2.520(7) and As–N 2.18(2), 2.12(2), 2.10(2)A with the latter directly opposite to the lone pair]. The anion is made up of a dinuclear (µ-oxo) Cl2As–O–AsCl2 unit with a single Cl– anion linked symmetrically to the two separate arsenic atoms [mean As–Clterminal 2.216(8), As–Clbridge 2.795(8)A]. Controlled hydrolysis of SbCl3L in acetonitrile solution provided colourless needle crystals of [H2L]2[Sb2OCl6]Cl22 as identified by X-ray diffraction studies. The structure of the dication shows protonation of two of the three nitrogen atoms with strong intramolecular hydrogen bonding N–H ⋯ N 2.70–2.85 A involving the third amine centre. This is the first structural characterisation of the diprotonated form of L. The structure of the accompanying chlorooxoantimony(III) anion can be described as a single (µ-oxo) Cl2Sb–O–SbCl2 unit linked to two chloride ions via secondary Sb ⋯ Cl bonding involving the two metal centres [mean Sb–Clterminal 2.435(3), Sb–Clbridge 2.863(3)A]. Each of the antimony(III) centres is further associated with a unique chloride anion, Sb ⋯ Cl– 3.550(7)A, which, in turn, forms close contacts with the two protonated nitrogen atoms of the triazamacrocycle Cl ⋯ H–N 3.07, 3.02 A. Treatment of L and SiMe3I in acetonitrile solution provided yellow needle crystals of [HL]I 3. X-Ray (diffraction) crystallographic characterisation revealed a monoprotonated ring (L) in which the single proton is bonded directly to one nitrogen atom and to the remaining two via intramolecular hydrogen N–H ⋯ N 2.71 A. The product isolated from the reaction of L and SiCl4 in the presence of antimony(V) chloride as halide abstractor in acetonitrile was identified by a crystal structure determination as [H2L]2[Sb2Cl9]Cl·MeCN·H2O 4. The structure reveals two [H2L]⋯Cl moieties which have dimensions similar to those found for 2. Conformational analyses have been carried out on free L and its mono-, di- and tri-protonated forms and the results are consistent with the experimental conformations observed in this work and elsewhere.

Crown ether complexation of scandium(III). Formation and spectroscopic characterisation of ScCl2+–oxacrown species and crystal structures of two scandium dibenzocrowns

The reaction systems ScCl3–SbCl5–MeCN–crown ether(L), where L = 6,7,9,10,17,18,20,21 -octa-hydrodibenzo[b,k][1,4,7,10,13,16] hexaoxacyclooctadecine (dibenzo-18-crown-6), 6,7,9,10,12,13,20,21,23,24,26,27 -dodecahydrodibenzo [b,n][1,4,7,10,13,16,19,22] octaoxacyclotetracosine (dibenzo-24-crown-8) and 6,7,9,10,12,13,15,16,23,24,26,27,29,30,32,33-hexadecahydrodibenzo [b,q][1,4,7,10,13,16,19,22,25,28] decaoxacyclotriacontine (dibenzo-30-crown-10), have been investigated. Halide abstraction generates the ScCl2+ cation in situ which can be stabilised by macrocyclic complexation with the appropriate cyclic ether. The compound [ScCl2(dibenzo-18-crown-6)][SbCl6] was isolated as a white solid and characterised as the hexachloroantimonate (V) salt from microanalytical and spectroscopic (IR, 1H and 13C NMR) data. Entrapment of a trans-ScCl2 unit within the ring cavity involving five-co-ordination of the ring oxygen atoms is seen as the most likely arrangement. Removal of a further chloride ion from this compound, effected by the addition of SbCl5(three equivalents), provides [ScCl(dibenzo-18-crown-6)(MeCN)][SbCl6]2 as established by microanalytical and spectroscopic data, and similar cavity entrapment of a trans-ScCl(MeCN) unit has been discussed. Solution studies, as monitored by 1H NMR spectroscopy, indicate that complete removal of chloride ion from [ScCl(dibenzo-18-crown-6)(MeCN)][SbCl6]2 can be effected but only with a heavy excess (10 equivalents) of SbCl5. The compound [ScCl2(dibenzo-24-crown-8)(H2O)][SbCl6]·2MeCN 1 was isolated as red crystals and structurally characterised by X-ray diffraction studies. Crystals are monoclinic, space group P21/n, Z= 4 and R 0.0638. The structure consists of [ScCl2(dibenzo-24-crown-8)(H2O)]+ cations and [SbCl6]– anions with two solvent (MeCN) molecules trapped in the lattice. For the cation the ScIII co-ordination geometry is essentially pentagonal bipyramidal involving two axial chlorine atoms [Sc–Cl 2.387(4) and 2.397(4)A, Cl–Sc–Cl 173.8(2)°] and five equatorial oxygen atoms comprising four from the crown ether with Sc–O distances in the range 2.184(7)–2.297(7)(mean 2.25 A) and one from a co-ordinated water molecule [Sc–Owater 2.130(8)A]. The threaded ScCl2+ unit is located within the ring cavity but in an ‘off-centre’ position. Intracavity hydrogen bonding of the type Sc–OH2⋯ Oring is present with Owater⋯ Oring 2.65 and 2.75 A. The compound [ScCl2(dibenzo-30-crown-10)(H2O)2][SbCl6]· MeCN·H2O 2 was isolated as yellow needle crystals and characterised crystallographically as the hexachloroantimonate (V) salt. Crystals are triclinic, space group P, Z= 2 and R= 0.0639. There are two solvent molecules (MeCN and H2O) trapped in the lattice. In the [ScCl2(dibenzo-30-crown-10)(H2O)2]+ cations the ScIII ion is seven-co-ordinate, involving bonds to three oxygens from the crown ether, two chlorine atoms and two water molecules, and shows distorted pentagonal-bipyramidal geometry. The trans-ScCl2 unit [Sc–Cl 2.411 (3) and 2.419(3)A, Cl–Sc–Cl 169.3(2)°] is located in an annexe section of the ring with Sc–Oring bond distances ranging between 2.208(8) and 2.280(8)(mean 2.25 A), Sc–Owater 2.148(9) and 2.160(8)A. Both of the co-ordinated water molecules are involved in a complex pattern of intracavity hydrogen bonding of the type Sc–OH2⋯ Oring with one molecule forming three Owater⋯ Oring close contracts in the range 2.83–2.98 A and the other forming four such contracts in the range 2.75–3.00 A.

Identification of the dysprosium(III) chloride solvate DyCl3(THF)3.5: crystal structure of the ion pair [trans-DyCl2(THF)5] [trans-DyCl4(THF)2]

Abstract Treatment of DyCl 3 (H 2 O) 6 with thionyl chloride in the presence of tetrahydrofuran provided colourless crystals of DyCl 3 (THF) 3.5 , subsequently identified as the ionic salt [ trans -DyCl 2 (THF) 5 ] [ trans -DyCl 4 (THF) 2 ] by an X-ray diffraction study. The dysprosium atom in the monocation is seven coordinate with the trans -DyCl 2 unit [Dy-Cl, 2.624(5)A˚] surrounded by five tetrahydrofuran molecules (Dy-O, mean 2.41(2)A˚) in a regular pentagonal bipyramidal geometry. For the anion the dysprosium atom is six coordinate with an octahedral geometry comprising four equatorial chlorine atoms (Dy%z.sbnd;Cl, mean 2.642(5)A˚) and two axial tetrahydrofuran molecules (Dy-O, 2.41(2)A˚).

Synthesis crystal structure of [GdCl2dibenzo-18-crown-6-MeCN][SbCl6]·2MeCN dibenzo-18-crown-6-2,3,11,12-dibenzo-1,4,7,10,13,16-hexaoxacyclooctadeca-2,11-diene

Treatment of GdCl3(THF)2 with an acetonitrile solution of antimony(V) chloride (as halide abstractor) in the presence of dibenzo-18-crown-6 provides the yellow crystalline salt [GdCl2(dibenzo-18-crown-6)(MeCN)][SbCl6]·2MeCN whose structure has been determined by single-crystal X-ray diffraction. The gadolinium atom is situated within the ring cavity bonded to all six oxygen atoms of the oxacrown Gd-O 2.545(4)–2.683(4) A. Further bonding to two chlorine atoms, located on opposite sides of the ring plane, GdCl 2.632(2) 2.679(2) A one acetonitrile molecule GdN 2.579(5) A, gives a nine-coordinate cation geometry approximating a planar hexagon with two capping atoms above one below the plane.

Sandwich-type crown ether complexation of scandium(III): Formation and structural identification of [Sc(1,4,7,10-tetraoxacyclododecane)2][SbCl6][Sb2Cl8(MeCN)2] ∗d 2MeCN

Abstract Addition of SbCl5 and SbCl3 to ScCl3(THF)3 in acetonitrile solution in the presence of 1,4,7,10-tetraoxacyclododecane(12-crown-4) led to the formation of the ionic compound [Sc(12-crown-4)2][SbCl6][Sb2Cl8(MeCN)2] ∗d 2MeCN. The structure was established by X-ray diffraction studies and showed an Sc3+ ion complexes by two oxacrown ligands (coordination number 8, distorted square-antiprismatic geometry) in a sandwich-type topology with separate [SbVCl6]− and dinuclear [Sb2IIICl8(MeCN)2]2− counteranions.

Crown ether complexation of PrCl2+: Synthesis and structural characterisation of [PrCl2(dibenzo-18-crown-6)(H2O)][SbCl6]·0.5MeOH·0.5MeCN

Abstract Treatment of PrCl3(MeCN)3.5 with antimony(V) chloride in the presence of dibenzo-18-crown-6 provided yellow needle crystals of [PrCl2(dibenzo-18-crown-6)(H2)][SbCl6]·0.5MeOH·0.5MeCN following recrystallisation of the initial reaction product from boiling CH3OH/CH3CN (50:50). The ionic formulation was verified by X-ray crystallography. The cations have crystallographic m symmetry and the metal atoms are nine coordinate involving binding to all six crown oxygen atoms PrOcrown 2.651(11)–2.668(10) A, mean 2.658(10) A, two chlorine atoms 2.740(4), 2.749(4) A and a water molecule PrOH2O 2.487(10) A.