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Acta Crystallographica Section B



Acta Crystallographica Section B: Structural Science, Crystal Engineering and Materials publishes scientific articles related to the structural science of compounds and materials in the widest sense. Knowledge of the arrangements of atoms, including their



Published: 2017-03-31

 












Characterization of fluorine-centred `F...O' σ-hole interactions in the solid state

2017-03-14

In the current study, the crystal structure of 1-(3-nitrophenyl)-2,2,2-trifluoroethanone (A1) and (E)-4-((4-fluorophenyl) diazenyl)phenol (A2) has been analyzed for the characterization of the presence of a `unique' and `rare' intermolecular C(sp3/sp2)—F...O contact, which has been observed to play a significant role in the crystal packing. Theoretical charge-density calculations have been performed to study the nature and strength associated with the existence of this intermolecular F...O contact, wherein the F atom is attached to an sp3-hybridized C atom in the case of A1 and to an sp2 hybridized carbon in the case of A2. The crystal packing of the former contains two `electronically different' Csp3—F...O contacts which are present across and in between the layers of molecules. In the latter case, it is characterized by the presence of a very `short' (2.708 Å) and `highly directional' (168° at ∠C4—F1...O1 and 174° at ∠C10—O1...F1) Csp2—F...O contact. According to the Cambridge Structural Database (CSD) study, it is a rare example in molecular crystals. Topological features of F...O contacts in the solid state were compared with the gas-phase models. The two-dimensional and three-dimensional static deformation density obtained from theoretical multipole modeling confirm the presence of a charge depleted region on the F atoms. Minimization of the electrostatic repulsion between like charges are observed through subtle arrangements in the electronic environment in two of the short intermolecular F...O contacts. These contacts were investigated using inputs from pair energy decomposition analysis, Bader's quantum theory of atoms in molecules (QTAIM), Hirshfeld surface analysis, delocalization index, reduced density gradient (RDG) plot, electrostatic potential surface and distributed atomic polarizability. The intermolecular energy decomposition (PIXEL) and RDG–NCI (non-covalent interaction) analysis of the F...O contacts establish the interaction to be dispersive in nature. The mutual polarization of an O atom by fluorine and vice versa provides real physical insights into the role of atomic polarizability in interacting atoms in molecules in crystals.



1,3,5-Tri(iodoethynyl)-2,4,6-trifluorobenzene: halogen-bonded frameworks and NMR spectroscopic analysis

2017-03-14

Halogen bonding is the non-covalent interaction between the region of positive electrostatic potential associated with a covalently bonded halogen atom, named the σ-hole, and a Lewis base. Single-crystal X-ray diffraction structures are reported for a series of seven halogen-bonded cocrystals featuring 1,3,5-tris(iodoethynyl)-2,4,6-trifluorobenzene (1) as the halogen-bond donor, and bromide ions (as ammonium or phosphonium salts) as the halogen-bond acceptors: (1)·MePh3PBr, (1)·EtPh3PBr, (1)·acetonyl-Ph3PBr, (1)·Ph4PBr, (1)·[bis(4-fluorophenyl)methyl]triphenylphosphonium bromide, and two new polymorphs of (1)·Et3BuNBr. The cocrystals all feature moderately strong iodine–bromide halogen bonds. The crystal structure of pure [bis(4-fluorophenyl)methyl]triphenylphosphonium bromide is also reported. The results of a crystal engineering strategy of varying the size of the counter-cation are explored, and the features of the resulting framework materials are discussed. Given the potential utility of (1) in future crystal engineering applications, detailed NMR analyses (in solution and in the solid state) of this halogen-bond donor are also presented. In solution, complex 13C and 19F multiplets are explained by considering the delicate interplay between various J couplings and subtle isotope shifts. In the solid state, the formation of (1)·Et3BuNBr is shown through significant 13C chemical shift changes relative to pure solid 1,3,5-tris(iodoethynyl)-2,4,6-trifluorobenzene.



A new tecton with parallel halogen-bond donors: a path to supramolecular rectangles

2017-03-14

A new tecton, 1,8-diiodoethynylanthracene, with two halogen-bond donor sites was synthesized and characterized. This tecton is capable of forming two parallel halogen bonds at once, which makes it a useful building block for the construction of a variety of supramolecular squares and rectangles.



Taking the halogen bonding–hydrogen bonding competition one step further: complexes of difluoroiodomethane with trimethylphosphine, dimethyl sulfide and chloromethane

2017-03-14

To rationalize the driving factors in the competition of halogen bonding and hydrogen bonding, the complexes of the combined halogen-/hydrogen-bond donor difluoroiodomethane with the Lewis bases trimethylphosphine, dimethyl sulfide and chloromethane are studied. For all Lewis bases, ab initio calculations lead to halogen- and hydrogen-bonded complexes. Fourier transform–IR experiments involving solutions of mixtures of difluoroiodomethane with trimethylphosphine(-d9) or dimethyl sulfide(-d6) in liquid krypton confirm the coexistence of a halogen-bonded and hydrogen-bonded complex. Also for solutions containing chloromethane, evidence of the formation of binary associations is found, but no definitive assignment of the multiple complex bands could be made. Using van't Hoff plots, the experimental complexation enthalpies for the halogen- and hydrogen-bonded complex of difluoroiodomethane with trimethylphosphine are determined to be −15.4 (4) and −10.5 (3) kJ mol−1, respectively, while for the halogen- and hydrogen-bonded complexes with dimethyl sulfide, the values are −11.3 (5) and −7.7 (6) kJ mol−1, respectively. The experimental observation that for both trimethylphospine and dimethyl sulfide the halogen-bonded complex is more stable than the hydrogen-bonded complex supports the finding that softer Lewis bases tend to favor iodine halogen bonding over hydrogen bonding.



Cyclic networks of halogen-bonding interactions in molecular self-assemblies: a theoretical N—X...N versus C—X...N investigation

2017-03-14

The geometries and energetics of molecular self-assembly structures that contain a sequential network of cyclic halogen-bonding interactions are investigated theoretically. The strength of the halogen-bonding interactions is assessed by examining binding energies, electron charge transfer (NBO analysis) and electron density at halogen-bond critical points (AIM theory). Specifically, structural motifs having intramolecular N—X...N (X = Cl, Br, or I) interactions and the ability to drive molecular self-assembly via the same type of interactions are used to construct larger self-assemblies of up to three unit motifs. N—X...N halogen-bond cooperativity as a function of the self-assembly size, and the nature of the halogen atom is also examined. The cyclic network of the halogen-bonding interactions provides a suitable cavity rich in electron density (from the halogen atom lone pairs not involved in the halogen bonds) that can potentially bind an electron-deficient species such as a metal ion. This possibility is explored by examining the ability of the N—X...N network to bind Na+. Likewise, molecular self-assembly structures driven by the weaker C—X...N halogen-bonding interactions are investigated and the results compared with those of their N—X...N counterparts.



The evaluation of QM/MM-driven molecular docking combined with MM/GBSA calculations as a halogen-bond scoring strategy

2017-03-14

The combination of quantum mechanics/molecular mechanics-driven (QM/MM) molecular docking with binding free-energy calculations was successfully used to reproduce the X-ray geometries of protein–ligand complexes with halogen bonding. The procedure involves quantum-polarized ligand docking (QPLD) to obtain the QM-derived ligand atomic charges in the protein environment at the B3PW91/cc-pVTZ level and the MM/GBSA (generalized-Born/surface area) algorithm to calculate the binding free energies of resultant complexes. The performance was validated using a set of 106 X-ray complexes and compared with the Glide and AutoDock VinaXB scoring functions in terms of RMSD and the reconstruction of halogen-bond geometry (distance and σ-hole angle). The results revealed that docking and scoring using the QPLD–GBSA procedure outperformed the remaining scoring functions in the majority of instances. Additionally, a comparison of the orientation of the top ranked binding poses calculated using the fixed atomic charges of ligands obtained from force-field parameterization and by QM calculations in the protein environment provides strong evidence that the use of QM-derived charges is significant.



Theoretical insights into the π-hole interactions in the complexes containing triphosphorus hydride (P3H3) and its derivatives

2017-03-29

The π-hole of triphosphorus hydride (P3H3) and its derivatives Z3X3 (Z = P, As; X = H, F, Cl, Br) was discovered and analyzed. MP2/aug-cc-pVDZ calculations were performed on the π-hole interactions in the HCN...Z3X3 complexes and the mutual influence between π-hole interactions and the hydrogen bond in the HCN...HCN...Z3X3 and HCN...Z3X3...HCN complexes studied. The π-hole interaction belongs to the typical closed-shell noncovalent interaction. The linear relationship was found between the most positive electrostatic potential of the π-hole (VS,max) and the interaction energy. Moreover, the VS,max of the π-hole was also found to be linearly correlated to the electrostatic energy term, indicating the important contribution of the electrostatic energy term to the π-hole interaction. There is positive cooperativity between the π-hole interaction and the hydrogen bond in the termolecular complexes. The π-hole interaction has a greater influence on the hydrogen bond than vice versa. The mutual enhancing effect between the π-hole interaction and the hydrogen bond in the HCN...HCN...Z3X3 complexes is greater than that in the HCN...Z3X3...HCN complexes.



Experimental investigation of halogen-bond hard–soft acid–base complementarity

2017-03-29

The halogen bond (XB) is a topical noncovalent interaction of rapidly increasing importance. The XB employs a `soft' donor atom in comparison to the `hard' proton of the hydrogen bond (HB). This difference has led to the hypothesis that XBs can form more favorable interactions with `soft' bases than HBs. While computational studies have supported this suggestion, solution and solid-state data are lacking. Here, XB soft–soft complementarity is investigated with a bidentate receptor that shows similar associations with neutral carbonyls and heavy chalcogen analogs. The solution speciation and XB soft–soft complementarity is supported by four crystal structures containing neutral and anionic soft Lewis bases.



Cocrystal assembled by 1,4-diiodotetrafluorobenzene and phenothiazine based on C—I...π/N/S halogen bond and other assisting interactions

2017-03-29

The halogen-bonded cocrystal of 1,4-diiodotetrafluorobenzene (1,4-DITFB) with the butterfly-shape non-planar heterocyclic compound phenothiazine (PHT) was successfully assembled by the conventional solution-based method. X-ray single-crystal diffraction analysis reveals a 3:2 stoichiometric ratio for the cocrystal (1,4-DITFB/PHT), and the cocrystal structure is constructed via C—I...π, C—I...N and C—I...S halogen bonds as well as other assisting interactions (e.g. C—H...F/S hydrogen bond, C—H...H—C and C—F...F—C bonds). The small shift of the 1,4-DITFB vibrational band to lower frequencies in FT–IR and Raman spectroscopies provide evidence to confirm the existence of the halogen bond. In addition, the non-planarity of the PHT molecule in the cocrystal results in PHT emitting weak phosphorescence and relatively strong delayed fluorescence. Thus, a wide range of delayed fluorescence and weak phosphorescence could play a significant role in selecting a proper π-conjugated system to engineer functional cocrystal and luminescent materials by halogen bonds.



Testing the tools for revealing and characterizing the iodine–iodine halogen bond in crystals

2017-03-29

To understand what tools are really suitable to identify and classify the iodine–iodine non-covalent interactions in solid organic polyiodides, we have examined the anisotropy of the electron density within the iodine atomic basin along and across the iodine–iodine halogen bond using the Laplacian of electron density, one-electron potential and electron localization function produced by Kohn–Sham calculations with periodic boundary conditions. The Laplacian of electron density exhibits the smallest anisotropy and yields a vague picture of the outermost electronic shells. The one-electron potential does not show such a deficiency and reveals that the valence electron shell for the halogen-bond acceptor iodine is always wider than that for the halogen-bond donor iodine along its σ-hole direction. We have concluded that the one-electron potential is the most suitable for classification of the iodine–iodine bonds and interactions in complicated cases, while the electron localization function allows to distinguish the diiodine molecule bonded with the monoiodide anion from the typical triiodide anion.



Halogen bonding stabilizes a cis-azobenzene derivative in the solid state: a crystallographic study

2017-03-29

Crystals of trans- and cis-isomers of a fluorinated azobenzene derivative have been prepared and characterized by single-crystal X-ray diffraction. The presence of F atoms on the aromatic core of the azobenzene increases the lifetime of the metastable cis-isomer, allowing single crystals of the cis-azobenzene to be grown. Structural analysis on the cis-azobenzene, complemented with density functional theory calculations, highlights the active role of the halogen-bond contact (N...I synthon) in promoting the stabilization of the cis-isomer. The presence of a long aliphatic chain on the azobenzene unit induces a phase segregation that stabilizes the molecular arrangement for both the trans- and cis-isomers. Due to the rarity of cis-azobenzene crystal structures in the literature, our paper makes a step towards understanding the role of non-covalent interactions in driving the packing of metastable azobenzene isomers. This is expected to be important in the future rational design of solid-state, photoresponsive materials based on halogen bonding.



Utilizing bifurcated halogen-bonding interactions with the uranyl oxo group in the assembly of a UO2–3-bromo-5-iodobenzoic acid coordination polymer

2017-03-29

The synthesis and crystal structure of a new uranyl coordination polymer featuring 3-bromo-5-iodobenzoic acid is described and the luminescent and vibrational properties of the material have been explored. Compound (1), [UO2(C7H3BrIO2)2]n, features dimeric uranyl units chelated and then linked by 3-bromo-5-iodobenzoic acid ligands to form a one-dimensional coordination polymer that is subsequently assembled via bifurcated halogen-bonding interactions with uranyl oxo atoms to form a supramolecular three-dimensional network. The asymmetric, bifurcated halogen-bonding interaction in (1) is notable as it represents the first observation of this synthon in a uranyl hybrid material. Raman and IR spectroscopy showed that halogen-bonding interactions with the uranyl oxo atoms result in small shifts in υ1 and υ3 frequencies, whereas luminescence spectra collected at an excitation wavelength of 420 nm reveal partially resolved uranyl emission.



Crystallographic insights into the structural aspects of thioctic acid based halogen-bond donor for the functionalization of gold nanoparticles

2017-03-29

The synthesis and self-assembly capabilities of a new halogen-bond donor ligand, 2,3,5,6-tetrafluoro-4-iodophenyl 5-(1,2-dithiolan-3-yl)pentanoate (1), are reported. The crystal structure of ligand (1) and the formation of a cocrystal with 1,2-di(4-pyridyl)ethylene, (1)·(2), both show halogen bonds involving the 4-iodotetrafluorobenzene moiety. Ligand (1), being a self-complementary unit, forms an infinite halogen-bonded chain driven by the S...I synthon, while the cocrystal (1)·(2) self-assembles into a discrete trimeric entity driven by the N...I synthon. Ligand (1) was also successfully used to functionalize the surface of gold nanoparticles, AuNP-(1). Experiments on the dispersibility profile of AuNP-(1) demonstrated the potential of halogen bonding in facilitating the dispersion of modified NPs with halogen-bond donors in pyridine.



Color-tunable phosphorescence of 1,10-phenanthrolines by 4,7-methyl/-diphenyl/-dichloro substituents in cocrystals assembled via bifurcated C—I...N halogen bonds using 1,4-diiodotetrafluorobenzene as a bonding donor

2017-03-29

Single-crystal X-ray diffraction reveals a series of phosphorescent cocrystals which were assembled by 1,4-diiodotetrafluorobenzene (1,4-DITFB) and either 4,7-dimethyl-1,10-phenanthroline (DMPhe), 4,7-diphenyl-1,10-phenanthroline (DPPhe) or 4,7-dichloro-1,10-phenanthroline (DClPhe) via C—I...N halogen bonding. These cocrystals, labeled (1), (2) and (3), respectively, are phosphorescent and a distinct change in phosphorescent color can be observed from orange–yellow, green to yellow–green, with well defined vibrational band maxima at 587, 520 and 611 nm for (1), (2) and (3). Based on the dependence of halogen bonding in sites and strength, we discussed the impact of substituents with different electron-withdrawing effects and steric hindrance on intermolecular noncovalent interactions and phosphorescence. The method of inducing and modulating phosphorescence by halogen bonding and other weak non-covalent interactions through changing the substituent groups of molecules should be significant in both theory and the application of optical function materials with predictable and modulated luminescent properties.



Relationships between hydrogen bonds and halogen bonds in biological systems

2017-03-29

The recent recognition that halogen bonding (XB) plays important roles in the recognition and assembly of biological molecules has led to new approaches in medicinal chemistry and biomolecular engineering. When designing XBs into strategies for rational drug design or into a biomolecule to affect its structure and function, we must consider the relationship between this interaction and the more ubiquitous hydrogen bond (HB). In this review, we explore these relationships by asking whether and how XBs can replace, compete against or behave independently of HBs in various biological systems. The complex relationships between the two interactions inform us of the challenges we face in fully utilizing XBs to control the affinity and recognition of inhibitors against their therapeutic targets, and to control the structure and function of proteins, nucleic acids and other biomolecular scaffolds.



Nature of E2X2 σ(4c–6e) of the X---E—E---X type at naphthalene 1,8-positions and model, elucidated by X-ray crystallographic analysis and QC calculations with the QTAIM approach

2017-03-29

The nature of E2X2 σ(4c–6e) of the X-*-E-*-E-*-X type is elucidated for 1-(8-XC10H6)E–E(C10H6X-8′)-1′ [(1) E, X = S, Cl; (2) S, Br; (3) Se, Cl; (4) Se, Br] after structural determination of (1), (3) and (4), together with model A [MeX---E(H)—E(H)---XMe (E = S and Se; X = Cl and Br)]. The quantum theory of atoms-in-molecules dual functional analysis (QTAIM-DFA) is applied. The total electron energy densities Hb(rc) are plotted versus Hb(rc) – Vb(rc)/2 for the interactions at the bond critical points (BCPs; *), where Vb(rc) show the potential energy densities at the BCPs. Data for the perturbed structures around the fully optimized structures are employed for the plots, in addition to those of the fully optimized structures. The plots were analysed using the polar coordinate (R, θ) representation of the data of the fully optimized structures. Data containing the perturbed structures were analysed by (θp, κp), where θp corresponds to the tangent line of the plot and κp is the curvature. Whereas (R, θ) shows the static nature, (θp, κp) represents the dynamic nature of interactions. E-*-E are all classified as shared shell (S) interactions for (1)–(4) and as weak covalent (Cov-w) in nature (S/Cov-w). The nature of pure CS (closed shell)/typical-HB (hydrogen bond) with no covalency is predicted for E-*-X in (1) and (3), regular CS/typical-HB nature with covalency is predicted for (4), and an intermediate nature is predicted for (2). The NBO energies evaluated for E-*-X in (1)–(4) are substantially larger than those in model A due the shortened length at the naphthalene 1,8-positions. The nature of E2X2 of σ(4c–6e) is well elucidated via QTAIM-DFA.



Incommensurately modulated twin structure of nyerereite Na1.64K0.36Ca(CO3)2

2017-03-29

The incommensurately modulated twin structure of nyerereite Na1.64K0.36Ca(CO3)2 has been first determined in the (3 + 1)-dimensional symmetry group Cmcm(α00)00s with modulation vector q = 0.383a*. Unit-cell values are a = 5.062 (1), b = 8.790 (1), c = 12.744 (1) Å. Three orthorhombic components are related by threefold rotation about [001]. Discontinuous crenel functions are used to describe the occupation modulation of Ca and some CO3 groups. The strong displacive modulation of the O atoms in vertexes of such CO3 groups is described using x-harmonics in crenel intervals. The Na, K atoms occupy mixed sites whose occupation modulation is described in two ways using either complementary harmonic functions or crenels. The nyerereite structure has been compared both with the commensurately modulated structure of K-free Na2Ca(CO3)2 and with the widely known incommensurately modulated structure of γ-Na2CO3.



Temperature-induced first-order displacive phase transition of isonicotinamide-4-methoxybenzoic acid co-crystal

2017-03-29

Isonicotinamide–4-methoxybenzoic acid co-crystal (1), C6H6N2O·C8H8O3, is formed through slow evaporation from methanol solution and it undergoes a first-order isosymmetry (monoclinic I2/a ↔ monoclinic I2/a) structural phase transition at Tc = 142.5 (5) K, which has been confirmed by an abrupt jump of crystallographic interaxial angle β from variable-temperature single-crystal XRD and small heat hysteresis (6.25 K) in differential scanning calorimetry measurement. The three-dimensional X-ray crystal structures of (1) at the low-temperature phase (LTP) (100, 140 and 142 K) and the high-temperature phase (HTP) (143, 150, 200, 250 and 300 K) were solved and refined as a simple non-disordered model with final R[F2 > 2σ(F2)] ≃ 0.05. The asymmetric unit of (1) consists of crystallographically independent 4-methoxybenzoic acid (A) and isonicotinamide (B) molecules in both enantiotropic phases. Molecule A adopts a `near-hydroxyl' conformation in which the hydroxyl and methoxy groups are positioned on the same side. Both `near-hydroxyl' and `near-carbonyl' molecular conformations possess minimum conformational energies with an energy difference of < 0.15 kJ mol−1 from a potential energy surface scan. In the crystal, molecules are joined into linear ABBA arrays by intermolecular N—H...O and O—H...N hydrogen bonds which were preserved in both phases. However, these ABBA arrays are displaced from planarity upon LTP-to-HTP transition and the changes in inter-array interactions are observed in two-dimensional fingerprint plots of their Hirshfeld surfaces. The PIXEL energies of each molecular pair in both phases were calculated to investigate the difference in intermolecular interaction energies before and after the displacement of ABBA arrays from planarity, which directly leads to the single-crystal-to-single-crystal phase transition of (1).



A potential Cu/V-organophosphonate platform for tailored void spaces via terpyridine mold casting

2017-03-29

The reaction of appropriate copper and vanadium salts with tetratopic methane tetra-p-phenylphosphonic acid (MTPPA) in the presence of 2,2′:6′:2′′-terpyridine (terpy) yielded the three-dimensional bimetallic copper vanadium phosphonate framework [{Cu(terpy)}4Cu(VO2)4(MTPPA-H)2]·4H2O (1). Terpy has no net contribution to the three-dimensional structure providing a potential platform for void space formation via mold-casting. The structure was characterized by single-crystal X-ray diffraction and thermogravimetric analysis (TGA). Magnetic measurements were performed using a SQUID magnetometer. The crystal structure of the methanol solvate of the free ligand, MTPPA·MeOH, was analysed using Hirshfeld surfaces and fingerprint plots.



Variable-temperature structural studies on valence tautomerism in cobalt bis(dioxolene) molecular complexes

2017-03-29

A variable-temperature single-crystal structural study of five valence tautomeric cobalt molecular complexes, CoII(3,5-DBSQ)2(DBPy)2 (1), CoII(3,5-DBSQ)2(DBPy)2·1.33C7H8 (1S), CoII(3,5-DBSQ)2(DCPy)2·C7H8 (2S), CoII(3,5-DBSQ)2(TBPy)2 (3) and CoII(3,5-DBSQ)2(TCPy)2 (4) (S = toluene, 3,5-DBSQ = 3,5-di-tert-butylsemiquinonate, DBPy = 3,5-dibromopyridine, DCPy = 3,5-dichloropyridine, TBPy = 3,4,5-tribromopyridine and TCPy = 3,4,5-trichloropyridine) is reported. The re-crystallization of (1S) in toluene at 277 K resulted in a concomitant formation of a solvent-free polymorph, CoII(3,5-DBSQ)2(DBPy)2 (1). Thermally induced valence tautomerism (VT) is observed only in (1S), (1) and (2S) [hs-CoII(3,5-DBSQ)2L2 ↔ ls-CoIII(3,5-DBSQ)(3,5-DBCat)L2 (hs = high spin, ls = low spin, 3,5-DBCat = 3,5-di-tert-butylcatecholate)], whereas (3) and (4) remain locked in the hs-CoII(3,5-DBSQ)2 state during cooling of the sample. Multi-temperature single-crystal studies demonstrate the change in cobalt coordination environment during the VT conversion. The non-solvated compound (1) shows a sharp VT transition (T1/2 ∼ 245 K with ΔT ∼ 10 K) from hs-CoII(3,5-DBSQ)2(DBPy)2 to ls-CoIII(3,5-DBSQ)(3,5-DBCat)(DBPy)2 oxidation state, whereas the other polymorph with lattice solvent (1S) results in a broad transition (T1/2 ∼ 150 K with ΔT ∼ 100 K). This increase in the VT transition temperature for (1) relative to (1S) illustrates the effect of lattice solvent on the VT transition mechanism. Additionally, the influence of halogen substitutions on the pyridine ring is discussed with respect to observed VT behaviour in the studied compounds.



Triclinic crystal structure distortion of multiferroic BiMn7O12

2017-03-29

The quadruple perovskite BiMn7O12 obtained via high-pressure synthesis was investigated by high-resolution synchrotron X-ray powder diffraction over a temperature range of 10 to 295 K. Careful Rietveld analysis reveals triclinic lattice distortion of BiMn7O12 at 295 K, which increases upon cooling to 10 K. Also hkl-dependent anisotropic Bragg reflection shape was introduced to give a precise description of the diffracted intensities. Importantly BiMn7O12 crystal structure was described in the non-centrosymmetric I1 triclinic space group. We also demonstrate the use of irreducible representations analysis (ISODISTORT program) for crystal structure distortion from Im to I1 space group. The irreducible representation which describes crystal structure distortion points towards possible ferroelectricity. Finally anisotropic thermal lattice expansion was observed.