R. Alan Howie

Hydrothermal synthesis of polymeric metal carboxylates from benzene-1,2,4,5-tetracarboxylic acid and benzene-1,2,4-tricarboxylic acid

Abstract Crystallisation of benzene-1,2,4,5-tetracarboxylic acid or benzene-1,2,4-tricarboxylic acid with divalent metal-ions Co, Mn or Zn and 2,2-bipyridyl gives coordination solids of composition [Co2(C10H2O8)(C10H8N2)2(H2O)] (1), [Co3(C9H3O6)2(C10H8N2)2(H2O)2] (2), [Mn3(C9H3O6)2(C10H8N2)2(H2O)2] (3) or [Zn3(C9H3O6)2(C10H8N2)2(H2O)2] (4). Each has a sheet structure with a distorted octahedral coordination environment.

Synthesis and characterisation of polymeric metal-ion carboxylates from benzene-1,3,5-tricarboxylic acid with Mn(II), Co(II) or Zn(II) and 2,2-bipyridyl, phenanthroline or a pyridyl-2-(1-methyl-1H-pyrazol-3-yl) derivative

A total of 13 new co-ordination solids have been prepared of composition [Co(HBTC)(PHEN)(H2O)] (12), [Mn-3(BTC)(2)(PHEN)(3)] (13), [Mn(HBTC)(6)(H2O)] (14), [Mn(HBTC)(7)(H2O)] (15), [Zn-3(BTC)(2)(6)(3)(H2O)(3)]. 4H(2)O (16), [Zn-(HBTC)(6)(H2O)] (17), [Zn(H2BTC)(2)(6)] (18), [Zn(HBTC)(7)(H2O)] (19), [Zn(HBTC)(8)(H2O)] (20), [Zn-2(HBTC)(2)(9)(2)]. 2H(2)O (21), [Zn(HBTC)(10)(H2O)].H2O (22), [Co(HBTC)(10)(H2O)].H2O (23) and [Co(HBTC)(11)(H2O)] (24) 6 = pyridine-2-(1-methyl-1H-pyrazol-3-yl); 7 = pyridine-2-(1-methyl-4-bromo-1H-pyrazol-3-yl); 8 = pyridine-2-(1-methyl-4-nitro-1H-pyrazol-3-yl); 9 = pyridine-2-(1-methyl-5-trifluoromethyl-1H-pyrazol-3-yl); 10 = pyridine-2-(1-methyl-5-tert-butyl-1H-pyrazol-3-yl); 11 = pyridine-2-(1-methyl-4-nitro-5-tert-butyl-1H-pyrazol-3-yl). Compounds 12, 14, 15 and 24 have similar structures which contain metal atoms in M2O2 rings. Compounds 17, 19 and 20 all contain single stranded coordinative chains. At low temperatures compounds 14 and 15 both have high spin S = 5 ground states.

Hydrothermal crystallisation of metal (II) orotates (M=nickel, cobalt, manganese or zinc). Effect of 2,2-bipyridyl, 2,2-dipyridyl amine, 1-methyl-3-(2-pyridyl)pyrazole, phenanthroline and 2,9-dimethyl-1,10-phenanthroline upon structure

Abstract Hydrothermal synthesis of orotic acid (H3L) with Ni(OAc)2·4H2O gives a green 1D co-ordinative network of composition [Ni(HL)(H2O)3] (3). The kinetic product [Ni(HL)·(H2O)4]H2O (4) can be prepared by conventional crystallisation. When boiled in water it is transformed into the thermodynamically favoured trihydrate 3. An unstable blue phase 5 that could not be characterised was also observed. Hydrothermal synthesis of orotic acid and M(OAc)2·4H2O (M=Ni, Co, Mn or Zn) and either 2,2-bipyridyl (bipy), 2,2-dipyridylamine (dpa), phenanthroline (phen), methyl-3-(2-pyridyl)pyrazole (pypz) or 2,9-dimethyl-1,10-phenanthroline (dmphen) gave infinite 1D co-ordinative networks of composition [M(HL)bipy(H2O)] (M=Co or Mn) (6–7) and complexes of composition [Ni(HL)bipy (H2O)2]2H2O (8); [Ni(HL)(dpa)(H2O)2]H2O (9); [Ni(HL)(phen)(H2O)2]·2H2O (10); [Ni(HL)(C9H9N3)(H2O)2]·2H2O (11); [Ni(HL)(dmphen)(H2O)] (12); [Zn(HL)bipy(H2O)] (13) and [Ni(HL)(dpa)2]·0.5H2O (14).

Further study of estertin trichlorides, Cl3SnCH2CH2CO2R. Lewis acidity towards acetonitrile. Crystal structure of Cl3SnCH2CH2CO2Pr-i

Abstract Crystals of Cl 3 SnCH 2 CH 2 CO 2 Pri-i are orthorhombic, space group P 2 1 2 1 2 1 with a 9.638(6), b 10.004(7) and c 12.848(8) A. The tin atom is five-coordinate with two chlorines and carbon equatorial and the remaining chlorine and the carbonyl oxygen axial, in a distorted trigonal-bipyramidal arrangement: (SnCl) ax 2.389(3), average (SnCl) eq 2.320(2), SnC 2.142(9), SnO 2.337(5) A. Apart from the equatorial chlorine and the terminal carbons in the isopropyl group, all non-hydrogen atoms are essentially coplanar. The molecule approaches C 2 v symmetry although not constrained to do so by the crystallographic space group. In MeCN solution, the compounds Cl 3 SnCH 2 CH 2 CO 2 R (I, R = Me, Pr-i, C 6 H 4 X (X = p -MeO, H, p -Cl, o -MeO or C 6 H 3 Cl 2 -2,4) form as equilibrium mixtures of 1/1 and 2/1 MeCN/I complexes; the chelate ring is broken in the 2/1 complexes. Equilibrium constants indicate that the strength of the intramolecular SnO coordination in I increases with the electron releasing ability of the R group.

The influence of cation upon the supramolecular aggregation patterns of dithiocarbamate anions functionalised with hydrogen bonding capacity—the prevalence of charge-assisted O–H⋯S interactions

A range of supramolecular architectures is found in the title dithiocarbamate salts, each with hydrogen bonding functionality in the form of aτ least one hydroxyl group. A common feature in the crystal packing is the prevalence of charge-assisted O–H⋯S hydrogen bonding. In [NH4][S2CN(CH2CH2OH)2] (1), a 3-D network is found mediated by cooperative O–H⋯S, N–H⋯O and N–H⋯S hydrogen bonding. Reducing the hydrogen bonding functionality by replacing the ammonium cation in (1) by the 4-aza-1-azoniabicyclo(2.2.2)octanium cation to give [DABCO-H][S2CN(CH2CH2OH)2] (2), results in a 2-D array. Further reduction of the hydrogen bonding functionality, this time by substituting a CH2CH2OH with an alkyl group to give [DABCO-H][S2CN(CH2CH2OH)CH3] (3) and [DABCO-H][S2CN(CH2CH2OH)CH2CH3] (4) allows for the formation of 1-D supramolecular chains. The introduction of alkali metal cations rather than protic cations removes the possibility of the hydroxyl-O participating in hydrogen bonding interactions as these now coordinate the alkali metal. In the sodium trihydrate, Na[S2CN(CH2CH2OH)2]·3H2O (5), O–H⋯O hydrogen bonds are found along with charge-assisted O–H⋯S contacts so that a 3-D network results. Substituting a CH2CH2OH group with a n-propyl group gives Na[S2CN(CH2CH2OH)CH2CH2CH3]·2H2O (6) and yields a 2-D array. For the anhydrous K[S2CN(CH2CH2OH)2] (7) and Cs[S2CN(CH2CH2OH)2] (8) salts, the crystal packing is dominated by charge-assisted O–H⋯S hydrogen bonding giving 3-D network structures. The systematic analysis of the crystal packing patterns of these salts reveals the importance of charge-assisted O–H⋯S hydrogen bonding in stabilising these crystal structures.

Synthesis and characterisation of polymeric manganese and zinc 5-hydroxyisophthalates

The crystallisation of 5-hydroxyisophthalic acid with divalent Mn or with Mn or Zn and either 2,2-bipyridine (2,2-bipy) or pyridine-2-(1H-pyrazol-3-yl) gave solids of composition [Mn(C8H4O5)(H2O)3]·2H2 O( 1), [Mn(C8H4O5)(2,2-bipy)]·H2 O( 2), [Mn2(C8H4O5)2(C8H7N3)2]·H2 O( 3) and [Zn(C8H4O5)(2,2-bipy)] (4). Each compound has 1D co-ordinative chains that are connected by hydrogen bonds. Compounds 2–4 contain M2C2O4 rings with pseudo-chair geometries. The Mn atoms in 2 are coupled antiferromagnetically.

Synthesis of bis[(ferrocenylmethyl)trimethylammonium] [bis(1,3-dithiole-2-thione-4,5-dithiolato)zincate] and [bis(1,3-dithiole-2-thione-4,5-dithiolato)zincate] salts, ([FcCH2NMe3]2[Zn(dmit)2] and [FcCH2NMMe3]2[Zn(dmio)2]): crystal structures of [FcCH2NMe3]2[Zn(dmio)2] and [NEt4]2[Zn(dmit)2]·MeOH

Abstract The crystal structures of [(ferrocenylmethyl)trimethyl-ammonium]2[Zn(dmit)2], [FcCH2 NMe3]2[Zn(dmit)2], (4), and {[NEt4]2[Zn(dmit)2]·MeOH} (5) are reported (dmit = 1,3-dithiole-2-thione-4,5-dithiolato). The dihedral angle between the C5 planes in the [FcCH2NMe3]+ cation of 4 is 1.66°; the C5 rings are within 1.6(4)° of an eclipsed conformation. The zinc atoms in both the ionic complexes have distorted tetrahedral geometries. The bite angles of the dmit ligands are 93.67(4)° in 4 and 93.43(8) and 94.01(9)° in 5, with the remaining SZnS bond angles having distinct values in the two complexes. The ZnS bond lengths are similar in the two complexes being in the range 2.3311(12) to 2.35(2) A. Different interanionic S…S contacts in the two complexes, at distances less than twice the van der Waals radius of S, lead to different packing arrangements. Spectral details (NMR, IR and UV-visible) of 4 and [FcCH2NMe3]2[Zn(dmio)2] (6, dmio = 1,3-dithiole-2-one-4,5-dithiolato) have also been obtained.

Some further studies of estertin compounds. crystal structures of [NEt4][MeO2CCH2CH2Sn(dmio)2] (dmio = 1,3-dithiole-2-one-4,5-dithiolato) and (MeO2CCH2CH2)2SnX2[X2 = I2, (NCS)2 or Cl, Br]

Abstract Estertn compounds, (MeO2CCH2CH2)2SnX2 [X2 = I2 (2); X2 = Br2 (9); X2 = Cl, Br (4)) or X2 = (NCS)2 (3)] have been obtained by halide exchange reactions of (MeO2CCH2CH2)2SnCl2. Crystal structure determinations of 2–4 revealed chelating MeO2CCH2CH2 units with distorted octahedral geometries at tin. The SnO bond lengths in the isothiocyanato complex, 3, are shorter [2.390(11) to 2.498(12), mean 2.439 A], with the chelate bite angles, CSnO, larger [74.3(7) to 78.2(6), mean 76.0°] than those in the halide analogues 2 and 4 [SnO = 2.519(2) to 2.541(8), mean 2.530 A; CSnO 72.8(3) to 73.9(4), mean 73.3°]. 1H, 13C and 119Sn NMR and IR spectra of 2–4 and 9 were determined in CDCl3 solution: the NMR spectra of (MeO2CCH2CH2)2SnX2 show the following trends: (i) both δ1Hα and δ13Cα, increase and (ii) both 2 J ( SnH ) and 1 J(SnC ) decrease in the sequence X2 = (NCS)2, Cl2, ClBr, Br2 and I2. The MeO2CCH2CH2 and dmio groups (dmio = 1,3-dithiole-2-one-4,5-dithiolato) are all chelating groups in (MeO2CCH2CH2)2Sn(dmio) (5). As shown by X-ray crystallography, the tin atom in the anion of solid [Q][MeO2CCH2CH2Sn(dmio)2] 6 (Q = NEt4) forms 5 strong bonds [to C and the 4 thiolato S atoms, SnS 2.459(2) to 2.559(2) A], arranged in a near trigonal bipyramidal array. There is an additional Intramolecular but weaker, interaction with the carbonyl oxygen atom [SnO = 3.111(5) A]; v(C=O) = 1714 cm−1 in solid 6 (Q = NEt4). NMR spectra of 5 and 6 are also reported.

Crystal structure and coordination chemistry of Cl3SnCH2CH2CH2CO2Et

Abstract The crystal and molecular structure of Cl3SnCH2CH2CH2CO2Et is reported. Crystals of Cl3SnCH2CH2CH2CO2Et are monoclinic, space group P21/c with a 8.0242(5), b 11.571(5), c 13.129(12) A and β 104.54(6)°. The tin atom is 5 coordinate with two chlorines and carbon equatorial and the remaining chlorine and the carbonyl oxygen axial, in a distorted trigonal bipyramidal arrangement: (SnCl)ax 2.382(4) A, average (SnCl)eq 2.310(3), SnC 2.125(12), SnO 2.405(8) A. The six-membered chelate ring is slightly boat-shaped. Coordination of the carbonyl group to tin persists in solution but is broken on complexation to Cl3SnCH2CH2CH2CO2Et by strong nitrogen donors (2,2′-bipyridyl, 1,10-phenanthroline and pyridine (2 moles)). Comparison of the formation constants for adducts of Cl3Sn(CH2)nCO2Et (A, n  2 or 3), both chelates with monodentate donors, D, suggests comparable acceptor strengths for A (n  2) and A (n  3) for 1/1 adduct formation but that A (n  2) is a weaker acceptor for 2D/A formation.

Synthesis and properties of bis(1,3-dithiole-2-thione-4,5-dithiolato)bismuthate(1-) salts, [Q][Bi(dmit)2]. Crystal structure of [AsPh4][Bi(dmit)2]·1/2DMSO: comparison of the solid state structures of [Q][Bi(dmit)2] and [Q][Sb(dmit)2]

Abstract Ionic complexes, [Q][Bi(dmit)2] (5:QNEt4, NBu4, 1,4-Me2-pyridinium and AsPh4), have been obtained from BiBr3 and [Q]2[Zn(dmit)2] [H2–dmit4,5-dimercapto-1,3-dithiole-2-thione]. As established by the crystal structure determination of [(5:QAsPh4)·1/2DMSO], the cations have near tetrahedral geometries and are well separated from the anions. The anions, containing chelating dmit ligands, are linked into chains via Bi–thiolato–S inter-anion bonds: Bi2S2 rings are formed within the chains, with Bi⋯Bi distances alternating between 3.7760(3) and 3.9092(3) A. The bismuth atoms are six-coordinate, arising from two inter-anion Bi–S [Bi–S=3.0391(13) and 3.1643(14) A] and four intra-anion Bi–S bonds [between 2.6680(13) and 2.8370(13) A], with stereochemistries, including the equatorial-sited stereochemically active lone pair, of distorted pentagonal bipyramids. There are no S⋯S contacts between the anions less than the sum of the van der Waals radii. Comparisons are made between the structure of [(5:QAsPh4)·1/2DMSO] and those reported previously for (5:QNEt4), [(5:QNEt4)·1/2Et2O] and [(5:QNBu4) as well as those for [Q][Sb(dmit)2] (4).