High-pressure single-crystal X-ray diffraction has been used to trap both the low-spin (LS) and high-spin (HS) states of the iron(II) Hofmann spin crossover framework, [FeII (pdm)(H2 O)[Ag(CN)2 ]2 ⋅H2 O, under identical experimental conditions, allowing the structural changes arising from the spin-transition to be deconvoluted from previously reported thermal effects.

Abstract Hydroxycalciomicrolite, Ca1.5Ta2O6(OH) is a new microlite-group mineral found in the Volta Grande pegmatite, Nazareno, Minas Gerais, Brazil. It occurs as isolated octahedral and as a combination of octahedral and rhombic dodecahedral crystals, up to 1.5 mm in size. The crystals are yellowand translucent, with a white streak and vitreous to resinous lustre. The mineral is brittle, with a Mohs hardness of 5-6. Cleavage is not observed and fracture is conchoidal. The calculated density is 6.176 g cm-3. Hydroxycalciomicrolite is isotropic, ncalc. = 2.010. The infrared and Raman spectra exhibit bands due to O-H stretching vibrations. The chemical composition determined from electron microprobe analysis (n = 13) is (wt.%): Na2O 0.36(8), CaO 15.64(13), SnO2 0.26(3), Nb2O5 2.82(30), Ta2O5 78.39(22), MnO 0.12(2), F 0.72(12) and H2O 1.30 (from the crystal structure data), O = F -0.30, total 99.31(32), yielding an empirical formula, (Ca1.48Na0.06Mn0.01)Σ1.55(Ta1.88Nb0.11Sn0.01)Σ2.00O6.00[(OH)0.76F0.20O0.04]. Hydroxycalciomicrolite is cubic, with unit-cell parameters a = 10.4205(1) Å, V = 1131.53(2) Å3 and Z = 8. It represents a pyrochlore supergroup,microlite-groupmineral exhibiting P4332 symmetry, instead of Fd3̅m. The reduction in symmetry is due to long-range ordering of Ca and vacancies on the A sites. This is the first example of such ordering in a natural pyrochlore, although it is known from synthetic compounds. This result is promising because it suggests that other species with P4332 or lower-symmetry space group can be discovered and characterized.

Reactions between the C,C-dicopper(l) derivative of ortho-carborane and ortho-, meta- and para-diiodobenzene are reported. The reaction with 1,2-C6H4I2 unexpectedly afforded 2,2 '-bis(1 '-ortho-carboranyl)biphenyl, HCB10H10CC6H4]2 2, whereas reactions with 1,3- or 1,4-C6H4I2 provided alternative routes to 1,3-bis(1 '-ortho-carboranyl)benzene 3 and 1,4-bis(1 '-ortho-carboranyl)benzene 4, respectively. The crystal structure of the biphenyl derivative 2 revealed significant distortions in the biphenylene framework attributable to the proximity of the two bulky carborane cages. UV absorption spectra and electrochemical data on 2 and 3 showed little electronic communication between the two carborane cages in either, and negligible pi-conjugation between the two ortho-phenylene rings in 2. However, substantial evidence was found of electronic communication between the carborane cages via the paraphenylene bridge in 4. B3LYP/6-31G* computations have been carried out on compounds 2 and 4, on 4,4 '-bis(ortho-carboranyl)biphenyl 6 and on 1,2-bis(1 '-ortho-carboranyl)benzene 7. Those on 2, 4 and 6 show the computed geometries to be in very good agreement with the experimental geometries: those on 7 allowed the reported molecular geometry of this compound to be revised and revealed a long cage C C bond of 1.725(3) angstrom. (C) 2014 Elsevier Ltd. All rights reserved.

We have determined the ultra-low temperature crystal structure of the archetypal single-molecule magnet (SMM) [Mn12O12(O2CMe)16(H2O)4]·4H2O·2MeCO2H (1) at 2 K, by using a combination of single-crystal X-ray and single-crystal neutron diffraction. This is the first structural study of any SMM in the same temperature regime where slow magnetic relaxation occurs. We reveal an additional hydrogen bonding interaction between the {Mn12} cluster and its solvent of crystallisation, which shows how the lattice solvent transmits disorder to the acetate ligands in the {Mn12} complex. Unusual quantum properties observed in 1 have long been attributed to disorder. Hence, we studied the desolvation products of 1, in order to understand precisely the influence of lattice solvent on the structure of the cluster. We present two new axially symmetric structures corresponding to different levels of desolvation of 1, [Mn12O12(O2CMe)16(H2O)4]·4H2O (2) and [Mn12O12(O2CMe)16(H2O)4] (3). In 2, removal of acetic acid of crystallisation largely resolves positional disorder in the affected acetate ligands, whereas removal of lattice water molecules further resolves the acetate ligand disorder in 3. Due to the absence of acetic acid of crystallisation, both 2 and 3 have true, unbroken S4 symmetry, showing for the first time that it is possible to prepare fully axial Mn12–acetate analogues from 1, via single-crystal to single-crystal transformations.

La bencidrilamina (BB2) y sus derivados obtenidos por sustitución arílica y/o amínica presentan actividad inhibidora de los espasmos de la musculatura lisa. Como punto de partida de una investigación cuya finalidad es el diseño de nuevos derivados con mayor actividad y especificidad se estudió, mediante difracción de rayos X de monocristal, la geometría de la bencidrilamina en su forma de clorhidrato, encontrándose que presenta una conformación helicoidal, con los anillos aproximadamente perpendiculares entre sí. Cálculos de mecánica molecular para la molécula libre de bencidrilamina y de su forma protonada (bencidrilamonio), utilizando distintos potenciales, muestran que la conformación de energía mínima depende de la inclusión o no de las interacciones coulombianas. Puesto que el estado relevante para la función biológica es en solución acuosa, se efectuaron cálculos de energía mínima en presencia de agua y se comenzó el análisis mediante dinámica molecular. La simulación se lleva a cabo a presión y temperatura constante en una caja cúbica en presencia de 216 moléculas de agua (SPC/E). Se discute la relación entre la geometría en el estado sólido y las geometrías predichas para la molécula libre y solvatada.

The use of crystal vibrational modes and frequencies calculated for the periodic system to complement a Translation Libration Screw (TLS) fit in the estimation of anisotropic displacement parameters (ADPs) of hydrogen atoms in molecular crystals is proposed. As a test case we have used the para-nitroaniline crystal, for which a reference set of ADPs has been obtained by performing a single crystal neutron diffraction study at 100K. Although the largest difference between estimated and experimental reference values amounts to 0.06Å2, this value being about six times the experimental uncertainty, the agreement is better than three experimental uncertainties for 33 out of the total of 36 ADPs. The performance of the suggested method, particularly for the amino atoms, is thoroughly analyzed.

X-ray diffraction experiments at very low temperatures require samples to be isolated from atmospheric conditions and held under vacuum. These conditions are usually maintained via the use of beryllium chambers, which also scatter X-rays, causing unwanted contamination of the sample's diffraction pattern. The removal of this contamination requires novel data-collection and processing procedures to be employed. Herein a new approach is described, which utilizes the differences in origin of scattering vectors from the sample and the beryllium to eliminate non-sample scattering. The program Masquerade has been written to remove contaminated regions of the diffraction data from the processing programs. Coupled with experiments at different detector distances, it allows for the acquisition of decontaminated data. Studies of several single crystals have shown that this approach increases data quality, highlighted by the improvement in internal agreement factor with the test case of cytidine presented herein.

A series of ruthenium(II) complexes with face-capping [9]ane-S-3 ligands are described. The compounds function as supramolecular receptors for anions via three tripodally arranged 3-aminopyridine ligands. The [9]ane-S-3 ligand stabilises the tripodal complexes which are more readily prepared and studied than their pi-arene ruthenium(II) analogues. Pyrenyl derivative 4 displays some activity as a photophysical anion sensor but the anion response is complicated by the complexes concentration dependent emission behaviour. The receptors bind common anions in relatively polar media forming both 1 : 1 and 1 : 2 host-anion complexes with the CH center dot center dot center dot anion interactions involving the thioether ring being implicated in anion binding as well as the convention NH donors.

The perovskite-like salt [p-CIC6H4NH3](2)CuCl4 1 exhibits a wealth of magnetic and structural phase transitions which have been probed by variable temperature single crystal X-ray diffraction, SQUID magnetometry, resonant ultrasound spectroscopy (RUS), EPR spectroscopy, DSC measurements and DFT calculations. Single crystal X-ray diffraction studies between room temperature and 3 K reveal a rich tapestry of structural changes; at 298 K the structure conforms to a monoclinic setting but undergoes a first order phase transition upon cooling below similar to 275 K to a higher symmetry orthorhombic cell. This is facilitated by a transition to an intermediate phase at similar to 277 K. Whilst the intermediate phase has a limited stability window (similar to 2 K) and has not been structurally determined, the two discrete phase transitions at 275.5 K and 277 K have been clearly detected by differential scanning calorimetry, EPR spectroscopy and RUS studies. On further cooling a dynamic relaxation process is observed in RUS measurements, evidenced by a Debye-like peak in the dissipation at similar to 140 K. Residual electron density maps from single crystal X-ray diffraction studies reveal that this may be associated with a freezing out of the NH3 center dot center dot center dot Cl hydrogen-bonding between cation and anion frameworks upon cooling. The activation barrier for this order/disorder process was estimated to be at least 27 kJ mol(-1) from the RUS data. Variable temperature dc SQUID data reveal that 1 is a 2D ferromagnet with antiferromagnetic interactions between layers below 9 K. Analysis of the temperature dependence of the magnetic susceptibility for T > 40 K reveals that 1 exhibits Curie Weiss behaviour with theta = +22.8 K indicative of dominant ferromagnetic interactions. Good agreement is observed between the strength of the ferromagnetic interaction extracted from the Weiss constant (J/k = +22.8 K) and that calculated by DFT (J/k = +25 to +28 K) and from EPR studies (J/k= +17 K). The presence of short range ferromagnetic interactions is reflected in a marked temperature dependence of the g-factors determined from EPR spectroscopy below 20 K and possibly a small elastic anomaly in the RUS data. RUS studies indicate a very small elastic anomaly associated with the transition to long range order, implying weak or no magnetoelastic effect. At fields above similar to 15 G a spin flip transition is induced and 1 displays metamagnetic behaviour, with a saturation magnetization of 0.96 mu(B). (C) 2012 Elsevier B.V. All rights reserved.

A series of novel thienyl aryleneethynylenes have been prepared by the Sonogashira cross-coupling of dibrominated or diiodinated thiophenes with arylacetylenes. Previously we have investigated the properties of 2,5-bis(phenylethynyl)thiophene, BPET (1), [Siddle et al., New J. Chem., 2007, 31, 841] and in this work we go on to make chemical modification of the central thienyl moiety and examine their influence on the photophysical properties of the arylethynylene thienyl system. Room and low temperature absorption and emission spectra have been recorded, along with fluorescence quantum yields and lifetimes. It is demonstrated that the 1,1-dioxides (3b & 4b) exhibit significant broadening of their fluorescence spectra relative to the other systems, which we attribute to some degree of charge transfer from the peripheral phenyl rings into the electron-deficient thiophene-1,1-dioxide moiety. Furthermore, a non-conjugated fused thiophene system (6b) displays phosphorescence at low temperature, which is rarely observed from aryleneethynylenes. DFT and TD-DFT calculations have been performed to assist understanding the observed properties.

Variable temperature single crystal X-ray diffraction and SQUID magnetometry experiments have revealed a gradual spin transition in [FeII(L)](ClO4)2 (where L=1,4,7-tris(2-aminophenyl)-1,4,7-triazacyclononane), centred around room temperature. The gradual nature of the spin transition has been attributed to the lack of significant intermolecular interactions between iron centres and the propensity of the counter ions to accommodate the internal strain in the crystal caused by spin crossover.

A comprehensive study of the magnetic and photomagnetic behaviors of cis-[Fe(picen)(NCS)(2) ] (picen = N,N'-bis(2-pyridylmethyl)1,2-ethanediamine) was carried out. The spin-equilibration was extremely slow in the vicinity of the thermal spin-transition. When the cooling speed was slower than 0.1 K  min(-1), this complex was characterized by an abrupt thermal spin-transition at about 70 K. Measurement of the kinetics in the range 60-70 K was performed to approach the quasi-static hysteresis loop. At low temperatures, the metastable HS state was quenched by a rapid freezing process and the critical T(TIESST) temperature, which was associated with the thermally induced excited spin-state-trapping (TIESST) effect, was measured. At 10 K, this complex also exhibited the well-known light-induced excited spin-state-trapping (LIESST) effect and the T(LIESST) temperature was determined. The kinetics of the metastable HS states, which were generated from the freezing effect and from the light-induced excitation, was studied. Single-crystal X-ray diffraction as a function of speed-cooling and light conditions at 30 K revealed the mechanism of the spin-crossover in this complex as well as some direct relationships between its structural properties and its spin state. This spin-crossover (SCO) material represents a fascinating example in which the metastability of the HS state is in close vicinity to the thermal spin-transition region. Moreover, it is a beautiful example of a complex in which the metastable HS states can be generated, and then compared, either by the freezing effect or by the LIESST effect.

Some new phosphorus(III) derivatives Ar(2)PX (X = Br, Cl, F or H), ArPX(2) (X = Br or Cl), Ar(3)P and Ar(t)BuPCl, with the 2,5-bis(trifluoromethyl)phenyl (Ar) substituent on phosphorus, have been prepared, and characterised by (31)P and (19)F NMR solution-state spectroscopy. The complexing ability of Ar(2)PX, Ar(3)P and Ar(t)BuPCl towards the dimeric platinum(II) complexes [PtY(μ-Y)(PEt(3))](2) (Y = Cl or Br, the latter for X = Br only) has also been investigated. Single-crystal X-ray diffraction studies at low temperature have been carried out for Ar(3)P, Ar(2)PCl and the hydrolysis or oxidation products Ar(2)P(H)OH and Ar(2)P(O)OH. The structures of Ar(3)P and Ar(2)PCl are particularly interesting as in each compound the geometry around P is approximately octahedral. In Ar(3)P there are three short contacts to fluorine as well as the three bonded C atoms for both of the independent molecules in the unit cell. For Ar(2)PCl there are two short P-F contacts, and the octahedron is completed by a weak P-P interaction to a neighbouring molecule. In both instances the lone pair on the P(III) centre appears to be stereochemically inactive, and does not play a significant role in the structure.

The remarkable room temperature structure of trimethyltin hydroxide comprises a total of 32 crystallographically independent SnMe3OH units arranged in four independent coordination polymer strands. We suggest that a Z' = 4 value is more appropriate than Z' = 32, reflecting the polymeric structure of the compound. DSC, single crystal and XRPD studies show that on cooling below ca. 160 K the structure undergoes a first order phase change to a symmetric Z' = 1 structure with just one crystallographically unique SnMe3OH unit. The phase change is reversible, and on warming past 176 K the high Z' structure is regenerated, in an endothermic transition. The Z' = 1 and 4 structures are an enantiotropic pair, and trimethyltin hydroxide represents a case where the higher Z' structure is the most stable form at high temperature with the high Z' value possibly arising from a consideration of the dynamics of the crystal as a whole.

The near-infrared two-photon absorption (TPA) spectra of a series of cyclometalated iridium complexes have been measured. These complexes exhibit moderately large TPA cross-sections of approximately 20 GM at the biological relevant wavelength of 800 nm. A new complex has been designed and synthesised, and found to have an increased cross-section of 44 GM at 800 nm. Full photophysical characterisation of this complex is presented.

SessionsC644 molecule.Each 2,2'-iminobenzoate unit is linking two Cu(II) ions in a bis-bidentate mode, and the phenantroline unit is acting as a blocking ligand.The unit cell parameters are: a = 31.7600(5), b = 9.8517(2), c = 14.4899(3)Ǻ, α = 90, β = 113.204(1),γ = 90º, V = 4167.00(14)Ǻ 3 , space group C 2/c.The magnetic properties of both compounds, namely the magnetization in function of the applied magnetic field and the susceptibility in function of the temperature will be presented and discussed.

Reaction of a diphosphane with a chlorophosphane in the presence of SnCl2 or AlCl3 leads to the formation of dicationic heterocycles with three (3P) or four (4P) linked phosphorus atoms. Some 3P derivatives with small alkyl substituents may also be prepared by direct alkylation of cyclic triphosphenium ions. Several new species were prepared in solution, some of which were isolated and characterised by single-crystal X-ray diffraction. Investigations into the factors favouring formation of 3P or 4P species are described.

An enantiotropic pair of polyrnorphs of (H-2-o-PDA(2+))(4)(H5O2+)(SO42)(4)(HSO4-)center dot 2H(2)O (1) interconvert at 140-142 K with a concomitant change in Z'. The details of the structural change are studied by single-crystal X-ray and neutron diffraction which shows that both forms are close packed with the difference resulting from the linearization of hydrogen bonds at low temperature as part of an extensive charge-assisted hydrogen-bonding network. The related (H-2-o-PDA(2+))(2)(SO42-)(2)center dot 3H(2)O (2) has also been characterized by single-crystal neutron diffraction and exhibits a disordered "flip-flop" water chain and short nonbonded O center dot center dot center dot O contacts enforced by NH3+center dot center dot center dot OSO32- hydrogen-bonded bridges. A total of seven other related salts have been isolated and structurally characterized revealing a surprisingly high incidence of Z' > 1 structures as a result of frustration in the charge-assisted hydrogen-bonded network.

Sessions C367to control polymorphism in pharmaceuticals.Our compound of interest is pyrazinamide (PZA), a polymorphic API used in the treatment of tuberculosis and is known to exist in 4 different forms.Only two cocrystals of PZA have been reported to date.We identified aminobenzoic acid (ABA) and hydroxybenzoic acid (HBA) as suitable cocystal formers (coformers) for PZA.In addition, we decided to investigate the effect of changing the orientation of the hydrogen bonding groups in ABA and HBA on cocrystal formation by employing the 3 constitutional isomers of each for a total of 6 coformers: o-aminobenzoic acid (oABA) commonly known as anthranilic acid, m-aminobenzoic acid (mABA), p-aminobenzoic acid (pABA), o-hydroxybenzoic acid (oHBA) commonly known as salicylic acid, m-hydroxybenzoic acid (mHBA) and p-hydroxybenzoic acid (pHBA).Our results show that PZA forms a cocrsytal with each of the coformers, repeatedly and consistently suggesting that they are not polymorphic.This presentation will show the synthesis and characterization of 6 new PZA cocrystals, namely PZA•oABA (1), PZA•mABA (2), PZA•pABA (3), PZA•oHBA (4), PZA•mHBA (5) and PZA•pHBA (6).The characterization techniques employed include powder X-ray diffraction (PXRD), differential scanning calorimetery (DSC), melting point, and in some cases 1 H NMR and single crystal X-ray crystallography (cocrystals 1 and 3).