Disordered Water Molecules Research Articles

1,4-Bis(1H-benzimidazol-2-ylmethyl)-1,4,7-triazacyclononane 4.5-hydrate

The title compound, C22H27N7·4.5H2O, crystallizes with two molecules of 1,4-bis(benzimidazol-2-ylmethyl)-1,4,7-triazacyclononane and nine disordered water molecules in the asymmetric unit. Each triazacyclononane group exhibits an intramolecular N—H...N hydrogen bond. The crystal packing is dominated by N—H...O and O—H...N hydrogen bonds between organic molecules and water molecules, and also between water molecules.

Structure of bovine β-lactoglobulin (variant A) at very low ionic strength

Bovine β-lactoglobulin (BLG) is a globular protein of uncertain physiological function and a member of the lipocalin superfamily of proteins. Here, we present the X-ray structure at 3.0 Å of BLG (variant A) from an orthorhombic ( P2 12 12 1) pseudo-tetragonal crystal form that suffers from pseudo-merohedral twinning (final R working = 0.224, R free = 0.265). Crystals were grown by dialysis against ultra-purified water (i.e., at very low ionic strength), at pH ∼5.2 (≈pI), conditions vastly different from all other BLG structures determined previously. This allows critical assessment of the BLG structure and of the influence that pH, ionic strength, and crystal packing may have on the molecular structure of BLG. The pH-sensitive EF loop is found in the closed conformation characteristic of BLG at pH less than 7 and moderate to high ionic strength. Although the hydrophobic pocket appears to be empty, the presence of highly disordered water molecules cannot be excluded. The dimer interface and the hydrophobic pocket (calyx) are preserved. However, the orientation of the subunits in the dimer varies considerably with crystal form. Structure is deposited with PDB ID 2akq.

Self-assembly of N,N′,N″-tris(4-pyridyl)trimesic amide and N,N′,N″-tris(3-pyridyl)trimesic amide with AgIor CdIIions

We report herein an interesting family of tripyridyltriamides (L1 ≡ N,N′,N″-tris(3-pyridyl)trimesic amide, L2 ≡ N,N′,N″-tris(4-pyridyl)trimesic amide) used as tridentate bridging ligands to carry out crystal-engineering studies. The reaction of AgPF6 with L1 leads to a 2-D coordination polymer, [Ag(L1)PF6]n (1). The 48-membered macrocycles constructed from three-coordinate AgI ions as connectors and three tripyridyltriamide moieties propagate into 2-D extended structures. Indeed, the AgI⋯π interaction (the distance of the AgI⋯centroid of benzene is 3.209 A) increases the supramolecular complexity, and leads to inter-sheet dimerization. The reaction of CdCl2 with L2 forms a 3-D coordination network, [Cd(L2)2Cl2]n (2). The open channels with a diameter of ca. 7.5 A containing the tripyridyltriamide moieties propagate into 3-D extended structures. This is an interesting example of 3-D coordination networks containing tripyridyltriamides as functional moieties inside the channels. However, the channels are filled with disordered water molecules and chloride anions, where the latter are appended through hydrogen-bonding interactions with the amide moieties inside the channels. In addition, 1 displays a high-energy emission with a maximum at ca. 450 nm, whereas 2 shows a low-energy emission with a maximum at ca. 532 nm. The former with a ca. 450 nm emission is assigned to an intraligand transition, and the latter with a ca. 532 nm emission is tentatively ascribed to a metal-to-ligand charge-transfer transition.

Conformational change induced by hydration:trans-dichlorobis[(1R,2R,3R,5S)-(–)-isopinocampheylamine]palladium(II) andtrans-dichlorobis[(1S,2S,3S,5R)-(+)-isopinocampheylamine]palladium(II) hemihydrate

The title compounds, trans-dichlorobis[(1R,2R,3R,5S)-(-)-2,6,6-trimethylbicyclo[3.1.1]heptan-3-amine]palladium(II), [PdCl2(C10H19N)2], and trans-dichlorobis[(1S,2S,3S,5R)-(+)-2,6,6-trimethylbicyclo[3.1.1]heptan-3-amine]palladium(II) hemihydrate, [PdCl2(C10H19N)2].0.5H2O, present different arrangements of the amine ligands coordinated to PdII, viz. antiperiplanar in the former case and (-)anticlinal in the latter. The hemihydrate is an inclusion compound, with a Pd coordination complex and disordered water molecules residing on crystallographic twofold axes. The crystal structure for the hemihydrate includes a short Pd...Pd separation of 3.4133 (13) A.

Molecular dynamics study of water penetration in staphylococcal nuclease

The ionization properties of Lys and Glu residues buried in the hydrophobic core of staphylococcal nuclease (SN) suggest that the interior of this protein behaves as a highly polarizable medium with an apparent dielectric constant near 10. This has been rationalized previously in terms of localized conformational relaxation concomitant with the ionization of the internal residue, and with contributions by internal water molecules. Paradoxically, the crystal structure of the SN V66E variant shows internal water molecules and the structure of the V66K variant does not. To assess the structural and dynamical character of interior water molecules in SN, a series of 10-ns-long molecular dynamics (MD) simulations was performed with wild-type SN, and with the V66E and V66K variants with Glu66 and Lys66 in the neutral form. Internal water molecules were identified based on their coordination state and characterized in terms of their residence times, average location, dipole moment fluctuations, hydrogen bonding interactions, and interaction energies. The locations of the water molecules that have residence times of several nanoseconds and display small mean-square displacements agree well with the locations of crystallographically observed water molecules. Additional, relatively disordered water molecules that are not observed crystallographically were found in internal hydrophobic locations. All of the interior water molecules that were analyzed in detail displayed a distribution of interaction energies with higher mean value and narrower width than a bulk water molecule. This underscores the importance of protein dynamics for hydration of the protein interior. Further analysis of the MD trajectories revealed that the fluctuations in the protein structure (especially the loop elements) can strongly influence protein hydration by changing the patterns or strengths of hydrogen bonding interactions between water molecules and the protein. To investigate the dynamical response of the protein to burial of charged groups in the protein interior, MD simulations were performed with Glu66 and Lys66 in the charged state. Overall, the MD simulations suggest that a conformational change rather than internal water molecules is the dominant determinant of the high apparent polarizability of the protein interior.

Hydrogen-bonded aggregations of oxo-cholic acids

The crystal structures of six new crystals of oxo-cholic acids (oxo-CA) are reported: (I) 3alpha,12alpha-dihydroxy-7-oxo-5beta-cholan-24-oic acid; (II) 3alpha,7alpha-dihydroxy-12-oxo-5beta-cholan-24-oic acid; (III) 7alpha-hydroxy-3,12-dioxo-5beta-cholan-24-oic acid; (IV-alpha) and (IV-beta) 12alpha-hydroxy-3,7-dioxo-5beta-cholan-24-oic acid; (V) 3,7,12-trihydroxy-5beta-cholan-24-oic acid. (IV-beta) is a pseudopolymorphic solvated form of (IV-alpha) and contains small channels which can trap disordered water molecules. In all the structures the four saturated cycles, forming the common alicyclic skeleton, have the same conformation, while the carboxylic side chain adopts flexible conformations in order to produce the most efficient crystal aggregations. The structures display a variety of supramolecular architectures dominated by networks of cooperative O-H...O hydrogen bonds forming different packing motifs often supported by weaker C-H...O interactions.

Molecular dynamics study of hydration of the protein interior

Molecular dynamics (MD) simulations were performed to study the patterns of hydration of cavities in the interior of staphylococcal nuclease (SN) and of the variants V66E and V66K. In these variants the polar groups of Glu and Lys are internal, and they affect the polarity and size of a small internal cavity. Internal water molecules were identified in the simulations based on their coordination state. They were characterized in terms of their residence times, average locations, dipole moment fluctuations, hydrogen bonding interactions, and interaction energies. The best agreement in the locations of MD and crystallographically determined water molecules was found for molecules that have residence times of several ns, and which display small mean square displacements in the MD simulations. In the simulations the hydrophobic cavity near Val-66 in the wild type contains a relatively disordered water molecule that has never been seen crystallographically. Consideration of the protein dynamics was found to be important when studying hydration in the protein interior: inside the protein the interaction energies of water molecules fluctuate less than in bulk water, giving rise to a favorable contribution to the chemical potential. The analysis of the MD trajectories revealed that the fluctuations in the protein structure (especially the loop elements) can strongly influence protein hydration by changing the patterns or strengths of hydrogen bonding interactions between water molecules and the protein, or by providing potential energy barriers for water penetration.

Tritopic (Cascade) and Ditopic Complexes of Halides with an Azacryptand

Structural aspects of the binding of halides in the octaaza cryptand (1,4,11,14,17,24,29,36-octa-azapentacyclo[12.12.12.2(6,9).2(19,22).2(31,34)]-tetratetraconta-6(43),7,9(44),19(41),20,22(42),31(39),32,34(40)-nonaene, N(CH2CH2NHCH2-p-xylyl-CH2NHCH2CH2)3N), L1, were examined for fluoride, chloride, and bromide. Crystallographic results for two different fluoride complexes indicated cascade-like coordination, with two fluoride ions inside the tren-based cavity, bridged by a water molecule. In the two different chloride structures, a single chloride and a water molecule occupied the cavity. The bromide structure contained two crystallographically independent cationic cryptands. Unit A consisted of a bromide on one side of the cavity and three disordered water molecules situated between the cryptand arms on the other side. Unit B also had a bromide inside the cavity at one side, but a single molecule of water was centered at the other side of the cavity. Association constants for the three ions, determined by NMR titrations in aqueous solution at pH 5, revealed log Ka=3.15(5), 3.37(3), and 3.34(4) for fluoride, chloride, and bromide, respectively.

Inorganic−Organic Hybrid Materials Containing Porous Frameworks: Synthesis, Characterization, and Magnetic Properties of the Open Framework Solids [{Co(4,4‘-Bipy)}V2O6] and [{Co2(4,4‘-Bipy)3(H2O)2}V4O12]·2H2O

Synthesis of two novel porous framework hybrid materials, [Co(4,4‘-bipy)V2O6] (1) and [{Co2(4,4‘-bipy)3(H2O)2}V4O12]·2H2O (2), and their characterization by infrared spectroscopy, thermogravimetry, elemental analysis, manganometric titration, surface area measurement, bond valence sum calculations, temperature-dependent magnetic susceptibility measurement, and single-crystal X-ray structure analyses is described. Both compounds exhibit remarkable thermal stability. The three-dimensional structures of 1 and 2 are composed of fused {VO4} motifs linked by {Co(4,4‘-bipy)} coordination polymers. The structure of 1 is comprised of {CoO3N2} trigonal bipyramids, linked in two dimensions by corner-sharing {VO4} tetrahedra and in the third dimension by the 4,4‘-bipyridine ligands. In the bimetallic layers, the cobalt centers are bridged alternately by {VO4} and {V2O7} units, generating alternating eight-membered {Co2V2O4} and twelve-membered {Co2V4O6} rings. The crystal structure of 2 consists of a novel three-dimensional network containing two types of octahedral Co2+ ions linked by a {V2O7} group. The cobalt centers in 2 are linked in three dimensions by bridging 4,4‘-bipyridine ligands. The structure contains rather large channels parallel to the c-axis. A disordered water molecule of crystallization is present in the channels. Crystal data for C10H8N2O6CoV2, 1: triclinic space group P1̄ (No. 2), a = 8.1517(4) Å, b = 8.5794(4) Å, c = 10.1233(5) Å, α = 87.0170(10)°, β = 75.9610(10)°, γ = 75.1740(10)°, V = 663.94(6) Å3, Z = 2, Dcalcd = 2.066 Mg·m-3, R1 = 0.0252 (all data), wR2 = 0.0669. Crystal data for C15H16N3O8CoV2, 2: monoclinic space group C2/c (No. 15), a = 30.4457(13) Å, b = 11.3540(5) Å, c = 11.5836(5) Å, β = 106.5390(10)°, V = 3838.6(3) Å3, Z = 8, Dcalcd = 1.824 Mg·m-3, final R1 = 0.0447 (all data), wR2 = 0.1259.

Novel Cyanide-Bridged Three-Dimensional Coordination Polymer Derived from an Octahedral Rhenium Cluster [Re6Te8(CN)6]4−: Synthesis and Crystal Structure of [{Mn(H2O)2(DMF)} 2Re6Te8(CN)6]·2H2O

The reaction of a water solution of K4Re6Te8(CN)6 with a solution of Mn(NO3)2 in 0.02M hydrochloric acid in the presence of DMF gave crystals of a cluster rhenium complex [{ Mn(H2O)2(DMF)}2Re6Te8(CN)6]·2H2O. The structure of the compound was determined by single crystal X-ray diffraction (a = 12.6679(9) A, b = 17.4524(12) A, c = 9.7882(6) A, β = 105.570(6)°, V = 2084.6(3) A3, Z = 2, space group P21/n, R = 0. 0389). In the complex, the [Re6Te8(CN)6]4− cluster anions are linked to Mn2+ cations by the cyanide bridges, the manganese cations being additionally coordinated by the DMF molecule and two water molecules. The neighboring clusters are joined by Re-C-N-Mn bridges into a three-dimensional framework possessing cavities filled with doubly disordered water molecules.

Making optimal use of empirical energy functions: force-field parameterization in crystal space.

Today's energy functions are not able yet to distinguish reliably between correct and almost correct protein models. Improving these near-native models is currently a major bottle-neck in homology modeling or experimental structure determination at low resolution. Increasingly accurate energy functions are required to complete the "last mile of the protein folding problem," for example during a molecular dynamics simulation. We present a new approach to reach this goal. For 50 high resolution X-ray structures, the complete unit cell was reconstructed, including disordered water molecules, counter ions, and hydrogen atoms. Simulations were then run at the pH at which the crystal was solved, while force-field parameters were iteratively adjusted so that the damage done to the structures was minimal. Starting with initial parameters from the AMBER force field, the optimization procedure converged at a new force field called YAMBER (Yet Another Model Building and Energy Refinement force field), which is shown to do significantly less damage to X-ray structures, often move homology models in the right direction, and occasionally make them look like experimental structures. Application of YAMBER during the CASP5 structure prediction experiment yielded a model for target 176 that was ranked first among 150 submissions. Due to its compatibility with the well-established AMBER format, YAMBER can be used by almost any molecular dynamics program. The parameters are freely available from www.yasara.org/yamber.

Crystal structure, infrared and raman spectra of tripotassium trisaccha-rinate dihydrate, K3(C7H4NO3S)3·2H2O

Abstract The crystal structure of tripotassium trisaccharinate dihydrate, K3(C7H4NO3S)3·2H2O, is triclic, space group $$P \bar 1, Z = 2$$ . It consists of three crystallographically independent potassium and saccharinato ions as well as two structurally different water molecules. Potassium coordination polyhedra are irregular, with K1 and K3 six-coordinated and the third one K2 seven-coordinated. The K−O distances range from 2.652(9) to 3.100(2) Å(mean: 2.790 Å) whereas the K−N distance is 3.025(3) Å. The water molecules W2 is disordered over three positions with occupancies of approximately 0.6, 0.2 and 0.2. The hydrogen atom (H1W1) of the ordered water molecule (O1W) is hydrogen bonded to the sulfonyl oxygen atom (O11) (R(O...O)=2.976(3) Å), whereas the other hydrogen atom (H2W1) is bifurcated to the carbonyl oxygen atom (O13) (R(O...O)=2.851(3) Å) and the disordered water molecules (O23W) (R(O...O)=3.067(12) Å). The carbonyl oxygens (O13, O23 and O33) and one of the disordered water molecules (O22W) are involved in C−H...O hydrogen bonds (R(C−H...O)=3.027(4)–3.304(9) Å). Structural characteristics of the studied compound are compared with the analogous trisodium trisaccharinate dihydrate and dipotassium sodium trisaccharinate monohydrate. Infrared and Raman spectra of the title compound have been analyzed in relation to the structure, and compared with the spectra of trisodium trisaccharinate dihydrate.

Novel cadmium–organic frameworks with nitrilotriacetate

AbstractNovel cadmium–organic frameworks incorporating nitrilotriacetate (NTA3−) and BPY (4,4′‐bipyridine) were synthesized under hydrothermal conditions and structurally characterized by single‐crystal x‐ray crystallography and other techniques. The crystal structure of CUmof‐7, [Cd4(BPY)5(NTA)2(H2O)4]ċ(NO3)2ċ(H2O)x, consists of infinite 2D cationic bilayers stacked along the c direction, and perforated by wide tubular channels filled with nitrate ions and highly disordered water molecules. CUmof‐8, [Cd4(BPY)4(NTA)2(H2O)10]ċ(BPY)ċ(NO3)2ċ (H2O)8, is a 1D metal–organic polymer produced by the self‐assembly of a bimetallic secondary building unit into a cationic chain, $[{\rm Cd}_2({\rm BPY})_2 ({\rm NTA})({\rm H}_{2} {\rm O})_5]_n^{n+}$. NTA3− appears in both crystal structures as an effective polydentate ligand which traps the Cd2+ metal ions inside three chelate five‐membered rings, eliminating available coordination sites and favouring the formation of 1D polymers (for CUmof‐8). Copyright © 2003 John Wiley & Sons, Ltd.

Hydrogen bonds and proton location in 1:1 and 2:1 complexes of N-methylmorpholine betaine with picric acid

The 1:1 and 2:1 complexes of N-methylmorpholine betaine (MMB) with picric acid (TNPH) have been prepared and their structures determined by X-ray diffraction. In the 1:1 complex, MMBH·TNP, betaine is protonated and carboxylate group forms a hydrogen bond with the picrate anion, the O⋯O distance is 2.588(4) Å. The 2:1 complex, (MMB) 2H·TNP·(1/2)H 2O, crystallises as semihydrate with partly disordered water molecule. The carboxylate groups of a pair of MMB molecules are bridged by a proton to form a dimeric cation with a short and asymmetric hydrogen bonds with O⋯O distance equals 2.458(5) Å. The FTIR spectrum of the 1:1 complex shows a strong absorption at ca. 2500 cm −1 due to the νOH vibration. A broad and intense absorption in the 1500–400 cm −1 region in the spectrum of the 2:1 complex is typical for a very short hydrogen bonds. NMR spectra of investigated complexes are discussed. (MMB) 2H·TNP·(1/2)H 2O complex is the first example of betaine homoconjugated cation with phenolate counter anion.

2-(4-Chlorophenyl)-1,3-dicyano-6,7-dihydro-4-imino-9,10-dimethoxybenzo[a]quinolizine-water (2/5).

Crystals of the title compound, C(23)H(17)ClN(4)O(2).2.5H(2)O, contain channels filled with highly disordered water molecules. The best structure refinement was obtained by removing the solvent contribution from the intensity data and refining against a solvent-free model. The central six-membered ring of the quinolizine molecule has a slightly distorted screw-boat conformation.

Disordered Crystal Structure of Bis[(2.2.2-Cryptand)Sodium] Bis[Aqua(Isothiocyanato)(μ-Isothiocyanato)Sodium] 2[Na(2.2.2-Crypt)] + · [Na 2 (NCS) 2 (μ-NCS) 2 (H 2 O) 2 ] 2–

Crystals of bis[(2.2.2-cryptand)sodium] bis[aqua(isothiocyanato)(μ-isothiocyanato)sodium]: 2[Na(C18H36N2O6)]+ · [Na2(NCS)2(μ-NCS)2(H2O)2]2– (I) were synthesized and studied by X-ray diffraction analysis. The disordered structure of I (a = 12.715 A, b = 10.458 A, c = 21.767 A, β = 102.56°, space group P21/n) was solved by the direct method and refined by the full-matrix least-squares method in anisotropic approximation to R = 0.058 from 3896 independent reflections (CAD4 automated diffractometer, λMoKα). The crystal consists of two complex ions [I1]+ and [I2]2– (molar ratio 2 : 1). The Na+ cation of the host–guest cation I1 is coordinated by all eight heteroatoms (6O + 2N) of the cryptand ligand. The coordination polyhedron of this Na+ cation is a distorted cube. The atoms of two groups (CH2–CH2 and CH2–O–CH2–CH2) in the cryptand ligand are disordered over two positions. The independent cation Na+ of the centrosymmetric binuclear complex anion I2 is coordinated by one bifurcated O atom of the disordered water molecule and by three N atoms of the SCN– ligands (including two bridging ligands). The coordination polyhedron of this Na+ caiotn is a distorted tetrahedron. The complex ions in the crystal structure of I are united by hydrogen bonds.

X-ray structure of nitric oxide reductase (cytochrome P450nor) at atomic resolution

Crystal structures of the nitric oxide reductase cytochrome P450nor (P450nor) in the ferric resting and the ferrous carbonmonoxy (CO) states have been determined at 1.00 and 1.05 A resolution, respectively. P450nor consists of 403 amino-acid residues (46 kDa) and is one of the largest proteins refined to this resolution so far. The final models have conventional R factors of 10.2% (ferric resting) and 11.7% (ferrous CO), with mean coordinate errors of 0.028 (ferric resting) and 0.030 A (ferrous CO) as calculated from inversion of the full positional least-squares matrix. Owing to the atomic resolution, novel features are found in the refined structures. Firstly, two orientations of the haem are observed both in the ferric resting and the ferrous CO states. Secondly, a disordered water molecule bound to the haem iron is found in the ferric resting state. In addition, the accurate structures at atomic resolution enabled the examination of general stereochemical parameters that are commonly used in refinement cycles of protein structures.

An orthorhombic crystal form of cyclohexaicosaose, CA26·32.59 H 2O: comparison with the triclinic form

Cycloamylose containing 26 glucose residues (cyclohexaicosaose, CA26) crystallized from water and 30% (v/v) polyethyleneglycol 400 in the orthorhombic space group P2 12 12 1 in the highly hydrated form CA26·32.59 H 2O. X-ray analysis of the crystals at 0.85 Å resolution shows that the macrocycle of CA26 is folded into two short left-handed V-amylose helices in antiparallel arrangement and related by a twofold rotational pseudosymmetry as reported recently for the (CA26) 2·76.75 H 2O triclinic crystal form [Geßler, K. et al. Proc. Natl. Acad. Sci. USA 1999, 96, 4246–4251]. In the orthorhombic crystal form, CA26 molecules are packed in motifs reminiscent of V-amylose in hydrated and anhydrous forms. The intramolecular interface between the V-helices in CA26 is dictated by formation of an extended network of interhelical CH⋯O hydrogen bonds; a comparable molecular arrangement is also evident for the intermolecular packing, suggesting that it is a characteristic feature of V-amylose interaction. The hydrophobic channels of CA26 are filled with disordered water molecules arranged in chains and held in position by multiple CH⋯O hydrogen bonds. In the orthorhombic and triclinic crystal forms, the structures of CA26 molecules are equivalent but the positions of the individual water molecules are different, suggesting that the patterns of water chains are perturbed even by small structural changes associated with differences in packing arrangements in the two crystal lattices rather than with differences in the CA26 geometry.

Molecular recognition in cyclodextrin complexes of amino acid derivatives. 1. Crystallographic studies of beta-cyclodextrin complexes with N-acetyl-L-phenylalanine methyl ester and N-acetyl-L-phenylalanine amide pseudopeptides.

Cyclodextrins (CDs) are widely utilized in studies of chiral and molecular recognition. By changing the functionality of the guest molecule, the effect of such changes on recognition by the host CD molecule can be examined. We report crystal structure determinations for two nearly isomorphous complexes of phenylalanine derivatives: beta-CD/N-acetyl-L-phenylalanine methyl ester and beta-CD/N-acetyl-L-phenylalanine amide. The complexes crystallize as hydrated head-to-head host dimers with two included guest molecules in space group P1. The crystal packing is such that it presents a nonconstraining hydrophobic pocket adjacent to a hydrophilic region, where potential hydrogen-bonding interactions with hydroxyl groups of neighboring cyclodextrin molecules and waters of hydration can occur. The two host molecules display very similar conformations; only a few of the primary hydroxyl groups are conformationally disordered. There are a number of changes in the location of water of hydration molecules, some of which are the result of different hydrogen-bonding interactions. For the different guest molecules, similar modes of penetration are observed in the CD torus; however, there is a 0.985-A shift in the position of the guest molecules in the host torus, which takes place without changing the hydrophobic interactions displayed by the phenyl side chains. This observation and the thermal motion of the guest molecules in the ester complex are taken as evidence that complex binding forces are weak. The pseudopeptides experience a significant degree of flexibility in the crystalline environment provided by CD dimers. Conformational differences of the pseudopeptide backbones and the presence of disordered water molecules in the host-guest interface provide examples of different hydrogen-bonding schemes of similar potential energy. The crystal system presents an opportunity to establish a database of molecular interactions for small peptides and peptide analogues with waters of hydration and functional groups in nonconstraining binding environments.

Synthesis and structure of the polymeric cluster compound [Mn(H2O)4]3[W4S4(CN)12]·nH2O containing very large cavities

The compound [Mn(H2O)4]3[W4S4(CN)12]·nH2O (1) was prepared by the reaction of an aqueous solution of MnSO4 with a glycerol solution of KCs5[W4S4(CN)12]·4H2O. Complex 1 was characterized by X-ray diffraction analysis and IR spectroscopy. According to the X-ray diffraction data, the three-dimensional polymeric framework of 1 comprises only 24.2% of the unit-cell volume. The volume of the cavities per formula unit is 1664 A3. The cavities are occupied by highly disordered water molecules.