Inclusion of Two PhP(O)(OH) 2 Guest Molecules into the Cavity of Macrocyclic Cavidand Cucurbit[8]uril

A new inclusion compound which is a supramolecular adduct of cucurbit[8]uril with two guest molecules of phenylphosphonic acid, PhP(O)(OH)₂, included into the cavity as ``two guests in host'' is reported. The guests match both size and hydrophilicity/hydrophobicity requirements. Two phenyl groups of molecules of PhP(O)(OH)₂ are directed toward the center of the large hydrophobic cavity whereas the PO(OH)₂ groups are outward-looking and bound with each hydrophilic portal of cucurbit[8]uril by a short hydrogen bond.     

Syntheses and crystal structures of supramolecular compounds of tetranuclear ZrIV and HfIV aqua hydroxo complexes with macrocyclic cavitand cucurbituril

Slow evaporation of hydrochloric acid solutions of zirconium(iv) or hafnium(iv) oxochlorides and cucurbituril in air afforded compounds with composition [M₄(OH)₈(H₂O)₁₆]Cl₈·(C₃₆H₃₆N₂₄O₁₂)·16H₂O, where M = Zr (1) or Hf (2). According to the X-ray diffraction data, complexes 1 and 2 are isostructural. Their crystal structures can be described as packings of polymer chains consisting of alternating cucurbituril molecules and tetranuclear cations [M₄(OH)₈(H₂O)₁₆]⁸⁺ linked to each other via an extensive network of hydrogen bonds. Compound 2 is the first structurally characterized tetranuclear hafnium aqua complex.     

Inclusion of nickel(<Emphasis Type="SmallCaps">II</Emphasis>) and copper(<Emphasis Type="SmallCaps">II</Emphasis>) complexes with aliphatic polyamines in cucurbit[8]uril

The inclusion compound of macrocyclic cavitand cucurbit[8]uril (CB[8]) with the nickel(II) complex containing the tetraazamacrocyclic ligand cyclam, {[Ni(cyclam)]@CB[8]}Cl₂··16H₂O (1), and the inclusion compounds of CB[8] with the copper(II) bis-ethylene-diamine complex, {trans-[Cu(en)₂(H₂O)₂]@CB[8]}Cl₂·{CB[8]}·42H₂O (2a) and {trans-[Cu(en)₂(H₂O)₂]@CB[8]}Cl₂·17H₂O (2b), were synthesized and characterized by X-ray diffraction analysis, IR and ESR spectroscopy, and electrospray mass spectrometry. Guest—host inclusion compounds can be directly synthesized starting from a metal complex and cucurbit[8]uril, as was exemplified by the preparation of compounds 2a and 2b.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2414–2419, November, 2004.     

Sandwich-type tetranuclear lanthanide complexes with cucurbit[6]uril: from molecular compounds to coordination polymers

Sandwich-type lanthanide complexes with macrocyclic ligand cucurbit[6]uril (C 36H 36N 24O 12, CB[6]) were synthesized under hydrothermal conditions from aqueous solutions of lanthanide(III) bromides, CB[6], and 4-cyanopyridine. According to X-ray analysis (Ln = La, Pr, Dy, Ho, Er, and Yb), the compounds with different structural types of lanthanide cores have a common fragment where the tetranuclear hydroxo complex is sandwiched between two macrocycles {(IN@CB[6])Ln 4(mu 3-OH) 4(IN@CB[6])} (6+) (IN = isonicotinate). The photoluminescence (for Ln = Eu) and Fourier transform ion cyclotron resonance mass spectra (for Ln = Pr, Dy, and Er) were studied. The compounds are used for the first time as precursors for the synthesis of lanthanide-silver heterometallic coordination polymers. The chainlike crystal structure of polymers (Ln = La, Pr, and Dy) is constituted by the sandwich complexes linked via the coordination of IN nitrogen atoms to the silver atoms.     

Jørgensen complex within a molecular container: selective encapsulation of trans-[Co(en)2Cl2]+ into cucurbit[8]uril and influence of inclusion on guest's properties

The unprecedented selective encapsulation of trans-[Co(en)2Cl2]+ from the mixture of trans and cis isomers into the cavity of macrocyclic cavitand cucurbit[8]uril (C48H48N32O16, CB[8]) leads to the inclusion compound {trans-[Co(en)2Cl2]@CB[8]}Cl.17H2O (1). Single-crystal X-ray analysis, 1H NMR, and ESI-MS spectra confirm the formation of host-guest complex 1 in both solid state and solution. The geometry of the complex cation alters significantly upon inclusion, which causes appreciable hypsochromic shifts of the absorption bands of the guest complex. According to TGA data, inclusion of trans-[Co(en)2Cl2]+ dramatically stabilizes the complex toward thermal decomposition. Encapsulation of trans-[Co(en)2Cl2]+ into the CB[8] cavity also increases the stability of the metal complex toward isomerization into the cis form. The supramolecular adduct {cis-[Co(en)2(H2O)2](CB[8])6}Cl3.ca109.5H2O (2) was isolated only after prolonged heating of an aqueous solution of 1 at 120 degrees C in an evacuated tube; it was characterized by X-ray crystallography, IR, and elemental analysis.     

Synthesis and Crystal Structure of (H)2[Y(H2O)8]2(NO3)8(C36H36N24O12)?13H2O

The compound of (H)₂[Y(H₂O)₈]₂(NO₃)₈(C₃₆H₃₆N₂₄O₁₂)13H₂O composition was obtained from a nitric acid solution of yttrium nitrate and a macrocyclic cavitand cucurbituryl. According to X-ray diffraction data, the crystal structure of the compound involves alternating layers of cucurbituryl molecules and eight-coordinate yttrium aqua complexes. The structure has a complex system of hydrogen bonds involving the oxygen atoms of cucurbituryl and water molecules and the nitrate anions and linking all structural elements of the crystal.     

Synthesis and crystal structures of PrIII and NdIII complexes with the macrocyclic cavitand cucurbit[6]uril

The [{Pr(NO₃)₂(H₂O)₃}{Pr(NO₃)(H₂O)₄} (C₃₆H₃₆N₂₄O₁₂)](NO₃)₃·4H₂O and [{Nd(NO₃)(H₂O)₄} ₂(NO₃@C₃₆H₃₆N₂₄O₁₂)][Nd(NO₃)₆] complexes were prepared by heating a mixture of lanthanide nitrates, cucurbit[6]uril, and water in a sealed tube. X-ray diffraction study demonstrated that the metal atoms in the former complex are linked to the macrocycle through tridentate coordination of the portal oxygen atoms of cucurbit[6]uril to the praseodymium(III) cation. The neodymium(III) complex is the first example of lanthanide compounds with cucurbit[6]uril belonging to coordination polymers. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1511–1517, September, 2006.     

Cluster Oxalate Complexes [W3(μ3-Q)(μ2-Q)3 (C2O4)3(H2O)3]2? (Q=S, Se): Mechanochemical Synthesis and Crystal Structure

Mechanochemical reaction of cluster coordination polymers (Q=S, Se) with solid leads to the cluster core excision with the formation of anionic complexes . Extraction of the reaction mixture with water followed by crystallization gives crystalline (main product) and (1) (minor product). In the case of the Se cluster, the complex could not be isolated, and the treatment of the aqueous extract with PPh₃ gave (2) in a low yield. Alternatively, it was obtained from and in high yield. Both 1 and 2 were characterized by X-ray structure analysis. Dedicated to Academician I. I. Moiseev on the occasion of his 75th birthday and in recognition of his outstanding contribution to cluster chemistry.     

Synthesis and crystal structure of [Fe4O2(H2O)10(C5H5NCOO)4](NO3)8 · 2H2O

Crystals of the tetranuclear complex [Fe₄O₂(H₂O)₁₀(C₅H₅NCOO)₄](NO₃)₈ · 2H₂O are obtained by the slow evaporation of an aqueous solution of iron(III) nitrate and isonicotinic acid. According to the X-ray diffraction data, four metal atoms lie in the same plane and together with two μ₃-O oxygen atoms form the fragment [Fe₄(μ₃-O)₂]¹⁰⁺. The [Fe₄O₂(H₂O)₁₀(C₅H₅NCOO)₄]⁸⁺ cation has been obtained and structurally characterized for the first time.     

Aquadimethylsulfoxide complexes of rare earth elements Pr,Eu, and Tm with the [Mo3S7Br7]3− cluster anion

New complexes of rare earth elements [Ln(DMSO)_m(H₂O)_n][Mo₃S₇Br₇], Ln=Pr, Eu, Tm were synthesized and investigated by X-ray diffraction analysis. In [Pr(DMSO)₆(H₂O)₂]³⁺ and [Eu(DMSO)₇(H₂O)]³⁺, the coordination polyhedra of Ln are distorted, square antiprisms (coordination number is 8); in [Tm(DMSO)₆(H₂O)]³⁺, the coordination polyhedron of Ln is a distorted pentagonal bipyramid (coordination number is 7). In all complexes, DMSO is coordinated via oxygen atoms. Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences. Swiss Technological Institute, Zurich, Switzerland. Translated fromZhurnal Strukturnoi Khimii, Vol. 36, No. 6, pp. 1046–1069, November–December, 1995. Translated by L. Smolina