Di­chloro­(norborna­diene)­platinum(II): a comparison with di­chloro­(cyclo­octa­diene)­platinum(II)

The crystal structure of the title compound, (bi­cyclo­[2.2.1]­hepta‐2,5‐diene)­di­chloro­platinum(II), [PtCl₂(C₇H₈)], has been determined from single‐crystal X‐ray analysis. The coordination sphere about the Pt atom is pseudo‐square planar, with shorter Pt—C distances than in the corresponding di­chloro­(cyclo­octa­diene)­platinum(II) complex.     

cis‐Di­chloro(5,8‐dioxa‐2,11‐dithia[12]‐o‐cyclo­phane)­palladium(II)

The preparation and crystal structure of the title compound, cis‐di­chloro­[6,9‐dioxa‐3,12‐di­thia­bi­cyclo­[12.4.0]­octadeca‐14,‐16,­18(1)‐tri­ene‐S,S′]­palladium(II), [PdCl₂(C₁₄H₂₀O₂S₂)], are described. The Pd atom has a square‐planar environment, coordinated to two S atoms of the di­thia­dioxa macrocycle and to two Cl^? ions. The non‐coordinating O atoms are oriented away from the metal coordination plane. Upon complexation, a bicyclic chelate structure, which consists of a seven‐ and an eleven‐membered ring, is formed.     

7‐Oxobi­cyclo­[2.2.1]­heptane‐1‐carboxylic acid and ()‐7‐oxobi­cyclo­[2.2.1]­hept‐5‐ene‐2‐endo‐carboxylic acid: hydrogen bonding in two norbornyl keto acids

Molecules of the title β‐keto acid, 7‐oxobi­cyclo­[2.2.1]­heptane‐1‐carboxylic acid, C₈H₁₀O₃, exhibit chirality due to the bridgehead carboxyl group, which is partially ordered and has a slightly asymmetric conformation. The mol­ecules form centrosymmetric hydrogen‐bonded carboxyl dimers [O?O 2.639 (2) Å]. The title alkenoic γ‐keto acid, ()‐7‐oxobi­cyclo­[2.2.1]­hept‐5‐ene‐2‐endo‐carboxylic acid, C₈H₈O₃, also forms typical centrosymmetric hydrogen‐bonded carboxyl dimers [O?O 2.660 (3) Å]. There is partial disorder of the carboxyl group in each compound.     

Chiral and meso‐bis([2.2]­para­cyclo­phan‐4‐yl)­methane and meso‐bis­([2.2]­para­cyclo­phan‐4‐yl) sulfide

The [2.2]­para­cyclo­phane groups of the title compounds, chiral and meso‐bis­(tri­cyclo­[8.2.2.2^4,7]­hexa­deca‐4,6,10,12,13,15‐hexa­en‐5‐yl)­methane (the former as a racemate), C₃₃H₃₂, and meso‐bis­(tri­cyclo­[8.2.2.2^4,7]­hexa­deca‐4,6,10,12,13,15‐hexa­en‐5‐yl) sulfide, C₃₂H₃₀S, show the characteristic structural features of the parent compound [2.2]­para­cyclo­phane and the related compound di­methylbis([2.2]­para­cyclo­phan‐4‐yl)­silane, C₃₄­H₃₆­Si: the aromatic rings are puckered, resulting in a boat conformation. The planes of the four coplanar C atoms are slightly twisted with respect to each other. The Csp³—Csp³ bond lengths of the ethyl­ene bridges are elongated by the electronic and steric effects of the skeleton.     

Diethyl 2-[cyano(toluene-4-sulfinyl)methylene]propanedioate and its Diels–Alder adduct with cyclopentadiene

The thermal Diels–Alder cyclo­additon reaction of diethyl 2-­[cyano­(toluene-4-sulfinyl)­methyl­ene]­propane­dioate, C₁₆H₁₇­NO₅S, with cyclo­penta­diene gave the pure racemates of two of the four possible diastereomers, with a complete π-facial selectivity and a high (80:20) endo/exo-sulfinyl selectivity. X-ray diffraction studies of diethyl 2-[cyano­(toluene-4-sulfinyl)­methyl­ene]­propane­dioate and the major isomer of the cyclo­addition product, namely diethyl 3-cyano-3-(toluene-4-sulfinyl)­bi­cyclo­[2.2.1]­hepta-5-ene-2,2-di­carboxyl­ate, C₂₁H₂₃­NO₅S, reveal that the conformation of the substituents on the acrylo­nitrile moiety produces both steric and electronic effects, which affect the stereoselectivity of the reaction.     

Linear chains in polymeric di­cyclo­hexyl­ammonium tri­butyl­(4‐oxo‐4H‐pyran‐2,6‐di­carboxyl­ato)­stannate and methyl­phenyl­ammonium tri­butyl(pyridine‐2,6‐di­carboxyl­ato)­stannate containing trigonal bipyramidal tin

catena‐Poly­[di­cyclo­hexyl­ammonium [tri­butyl­tin‐μ‐(4‐oxo‐4H‐pyran‐2,6‐di­carboxyl­ato‐O²:O⁶)]], (C₁₂­H₂₄N)­[Sn(C₇­H₂­O₆)(C₄H₉)₃], consists of 4‐oxo‐4H‐pyran‐2,6‐di­carboxyl­ato groups that axially link adjacent tri­butyl­tin units into a linear polyanionic chain. The ammonium counter‐ions surround the chain, and each cation forms a pair of hydrogen bonds to the double‐bond carbonyl O atoms of the same dianionic group. The chain propagates in a zigzag manner along the c axis of the monoclinic cell. In catena‐poly­[methyl­(phenyl)­ammonium [tri­butyl­tin‐μ‐(pyridine‐2,6‐di­carboxyl­ato‐O²:O⁶)]], (C₇H₁₀N)­[Sn(C₇H₃NO₄)­(C₄H₉)₃], the pyridine‐2,6‐di­carboxyl­ato groups also link the tri­butyl­tin groups into a chain, but the hydrogen‐bonded chain propagates linearly on the ac face of the monoclinic cell.     

20‐Di­cyano­methyl­ene‐5,8,11,14‐tetraoxa‐2,17‐di­thia­bi­cyclo­[16.4.1]­tricosa‐1(23),18,21‐triene and its mercury(II) dichloride complex

The structures of the title compound, C₂₀H₂₄N₂O₄S₂, and its mercury(II) dichloride complex, dichloro{20‐di­cyano­methyl­ene‐5,8,11,14‐tetraoxa‐2,17‐di­thia­bi­cyclo­[16.4.1]­tricosa‐1(23),18,­21‐tri­ene‐κ⁴O,κS¹⁷}mercury(II), [HgCl₂(C₂₀­H₂₄­N₂­O₄­S₂)], have been determined by X‐ray crystallographic analyses. The mercury(II) dichloride complex has two independent mol­ecules of [HgCl₂(C₂₀H₂₄N₂O₄S₂)] in the lattice. The mercury(II) ion has pentagonal bipyramidal coordination which involves one S atom, four O atoms and two Cl^? ions.     

(1R*,11R*)‐Bi­cyclo­[9.4.1]­hexa­decane‐12,16‐dione

The title compound, C₁₆H₂₆O₂, (I), prepared by oxidation of (1R*,11R*)‐12‐hydroxy­bi­cyclo­[9.4.1]­hexa­decan‐16‐one using pyridinium dichromate, has a trans configuration of the two fused rings and represents an interesting precursor for the synthesis of macrocyclic structures.     

The gossypol–cyclo­dodecanone (1/2) inclusion complex

Gossypol and cyclo­dodecanone crystallize at room temperature as an inclusion complex in a 1:2 molar ratio. This complex, viz. 1,1′,6,6′,7,7′‐hexa­hydroxy‐5,5′‐diiso­pro­pyl‐3,3′‐di­methyl‐2,2′‐bi­naphthalene‐8,8′‐di­carbox­aldehyde–cyclo­do­deca­none (1/2), C₃₀H₃₀O₈·2C₁₂H₂₂O, is unusual in that there is limited intermolecular hydrogen bonding within the structure. Each cyclo­dodecanone mol­ecule accepts a hydrogen bond from a gossypol mol­ecule, but there are no gossypol‐to‐gossypol hydrogen‐bond interactions. The gossypol mol­ecules form a framework structure enclosing channels, and the cyclo­dodecanone mol­ecules lie in these channels. In terms of the number of non‐H guest atoms, this is the largest gossypol inclusion complex reported to date.     

Two new conformationally restricted 4,5‐dihydroxynorvaline analogues with a norbornane skeleton

The structures of two conformationally restricted 4,5‐di­hydroxy­norvaline analogues with a norbornane skeleton, namely methyl (1S,2S,3R,4R)‐2‐benz­amido‐3‐(1,2‐di­hydroxy­ethyl)­bi­cyclo[2.2.1]­heptane‐2‐carboxyl­ate, C₁₈H₂₃NO₅, and methyl (1R,2S,3R,4S)‐2‐benz­amido‐3‐(1,2‐di­hydroxy­ethyl)­bi­cyclo[2.2.1]­heptane‐2‐carboxyl­ate, C₁₈H₂₃NO₅, exhibit a conformation in the helical region of the ?,ψ map but their handedness is opposite. In both cases, the torsion angles (χ^1,1) giving the relative orientation of the 1,2‐di­hydroxy­ethyl group of the amino acid side chain and the benz­amide group of the peptide chain indicate that these groups adopt a nearly eclipsed conformation. Both compounds show a complex hydrogen‐bonding pattern.     

{(E)‐ and {(Z)‐2‐[α,β‐bis­(methoxy­carbonyl)­vinyl]­cyclo­pentadien‐1‐yl­idene}tri­phenyl­phospho­rane

The Ramirez yl­ide undergoes electrophilic substitution with di­alkyl acetyl­ene­di­carboxyl­ates, yielding a mixture of the Z and E adducts. The crystal structure analyses of the two adducts formed using di­methyl­acetyl­ene, viz. di­methyl (E)‐ and (Z)‐1‐[2‐(tri­phenyl­phospho­ranyl­idene)­cyclo­pentadien‐1‐yl]­ethyl­ene­di­carboxyl­ate, both C₂₉H₂₅O₄P, explain an unusual chemical shift observed for the vinyl H atom of the Z adduct, which had previously precluded a definitive assignment of the isomers. In addition, the structures explain why only one of the isomers reacts further with acetyl­ene esters to produce azulenes with a rare substitution pattern.     

11‐Hydro­xy‐3,3‐di­methyl‐7,12‐dioxo‐3,4,6,6a,7,12,12a,12b‐octa­hydro­benz­[a]­anthracen‐1‐yl acetate

The Diels–Alder reaction between 5‐hydroxy‐1,4‐naphtho­quinone and 5,5‐di­methyl‐3‐vinyl‐1,2‐cyclo­hexa­dienyl acetate by endo addition gives the title compound, C₂₂H₂₂O₅, in 68% yield. This racemic diastereoisomer has the opposite regiochemistry to ochromycinone analogues produced previously and may allow access to a new type of anticancer‐active saqua­yamycin analogue.     

The 1:1 adduct of 5‐methylbenzene‐1,3‐diol (orcin) and 1,4‐di­aza­bicyclo­[2.2.2]­octane

In the title adduct, C₆H₁₂N₂·C₇H₈O₂, the orcin and 1,4‐di­aza­bi­cyclo­[2.2.2]­octane moieties are held together by O—H⋯N hydrogen bonds. One‐dimensional chiral hydrogen‐bonded chains are formed along the b axis. Neighbouring chains are held together principally by van der Waals interactions and are interrelated by translation, resulting in a chiral layer.     

cis‐Verbenol

cis‐Verbenol (alternative name: 4,6,6‐tri­methyl­bi­cyclo­[3.1.1]­hept‐3‐en‐2‐ol), C₁₀H₁₆O, forms an orthorhombic P2₁2₁2₁ crystal that contains three mol­ecules per asymmetric unit. These three mol­ecules form hydrogen‐bonded helices parallel to the shortest axis of the lattice. The O?O distances associated with the hydrogen bonds are 2.760 (3), 2.760 (3) and 2.766 (3) Å.     

Inclusion of diprotonated [2.2.2]cryptand in the cavity of uranyl‐complexed p‐phenyl­tetra­homodioxacalix[4]arene

In the title compound, 4,7,13,16,21,24‐hexa­oxa‐1,10‐diazo­nia­bicyclo­[8.8.8]hexa­cosane dioxo[7,13,21,27‐tetra­phenyl‐3,17‐di­oxa­penta­cyclo­[23.3.1.1^5,9.1^11,15.1^19,23]ditriaconta‐1(29),5,7,9(30),11(31),12,14,19(32),20,22,25,27‐dodeca­ene‐29,30,31,32‐tetra­olato]uranium dimethyl sulfoxide tri­solvate, (C₁₈H₃₈N₂O₆)[U(C₅₄H₄₀O₆)O₂]·3C₂H₆OS, the uranyl ion is bound to the four phenoxide groups of the deprotonated p‐phenyl­tetra­homodioxacalix[4]arene ligand in a cone conformation, resulting in a dianionic complex. The diprotonated [2.2.2]cryptand counter‐ion is located in the cavity defined by the eight aromatic rings of the homooxacalixarene, where it is held by cation–anion, cation–π and possibly C—H⋯π inter­actions. Dimerization in the packing leads to the formation of sandwich assemblages in which two diprotonated [2.2.2]cryptands are encompassed by two uranyl complexes.     

Two isomers of 2,4‐di­benzyl‐8‐azabicyclo­[3.2.1]­octan‐3‐ol

The crystal structures of the title compounds, 2α,4α‐di­benzyl‐3α‐tropanol (2α,4α‐di­benzyl‐8‐methyl‐8‐aza­bi­cyclo­[3.2.1]­octan‐3α‐ol), C₂₂H₂₇NO, (I), and 2α,4α‐di­benzyl‐3β‐tropanol (2α,4α‐di­benzyl‐8‐methyl‐8‐aza­bi­cyclo­[3.2.1]­octan‐3β‐ol), C₂₂H₂₇NO, (II), show that both compounds have a piperidine ring in a chair conformation and a pyrrolidine ring in an envelope conformation. Isomer (I) is asymmetric, the benzyl groups having different orientations, whereas isomer (II) is mirror symmetric, and the N and O atoms, the C atom attached to the hydroxy group, and the methyl C atom attached to the N atom lie on the mirror plane. In the crystal structures of both (I) and (II), the mol­ecules are linked together by intermolecular O—H⋯N hydrogen bonds to form chains that run parallel to the a direction in (I) and parallel to b in (II).     

NiII and ZnII complexes of the hexadentate macrocyclic ligand cis‐6,13‐di­methyl‐1,4,8,11‐tetra­aza­cyclo­tetra­decane‐6,13‐di­amine

The title pendent‐arm macrocyclic hexa­amine ligand binds stereospecifically in a hexadentate manner, and we report here its isomorphous Ni^II and Zn^II complexes (both as perchlorate salts), namely (cis‐6,13‐di­methyl‐1,4,8,11‐tetra­aza­cyclo­tetra­decane‐6,13‐di­amine‐κ⁶N)­nickel(II) di­per­chlorate, [Ni(C₁₂H₃₀N₆)]­­(ClO₄)₂, and (cis‐6,13‐di­methyl‐1,4,8,11‐tetraaza‐cyclo­tetra­decane‐6,13‐di­amine‐κ⁶N)­zinc(II) di­per­chlorate, [Zn(C₁₂H₃₀N₆)]­(ClO₄)₂. Distortion of the N—M—N valence angles from their ideal octahedral values becomes more pronounced with increasing metal‐ion size and the present results are compared with other structures of this ligand.     

[(1R,2R)‐1,2‐Di­amino­cyclo­hexane‐κ2N,N′](α‐di­imine‐κ2N,N′)­platinum(II) bis­(hexa­fluoro­phosphate), where α‐di­imine is 2,2′‐bi­pyridine and 1,10‐phen­anthroline

The title Pt^II complexes, viz. (2,2′‐bi­pyridine‐κ²N,N′)[(1R,2R)‐1,2‐di­amino­cyclo­hexane‐κ²N,N′]­platinum(II) bis­(hexa­fluoro­phosphate), [Pt(C₆H₁₄N₂)(C₁₀H₈N₂)](PF₆)₂, and [(1R,2R)‐1,2‐di­amino­cyclo­hexane‐κ²N,N′](1,10‐phenanthroline‐κ²N,N′)platinum(II) bis­(hexa­fluoro­phosphate), [Pt(C₆H₁₄N₂)(C₁₂H₈N₂)](PF₆)₂, containing an aromatic α‐di­imine and a non‐planar di­amino­cyclo­hexane, both form a ladder‐type structure, which is constructed via loose π–π stacking on the α‐di­imine ligands and hydrogen bonding between the cyclic amines and the counter‐anions. In the former compound, there are two independent complex cations, both of which have a twofold axis through the Pt atom.     

A new polymorph of cis–transoid–cis‐dicyclohexano‐18‐crown‐6

A new orthorhombic polymorphic modification of the title compound (alternative name: cis–transoid–cis‐2,5,8,15,18,21‐hexaoxatri­cyclo­[20.4.0.0^9,14]­hexa­cosane), C₂₀H₃₆O₆, has been found and is compared with the previously known monoclinic modification. In the structures of the two polymorphs, the crown‐ether mol­ecules are centrosymmetric and reveal essen­tially the same molecular shape but different packing motifs.     

An ion pair formed by protonated Fe(cp*py)2 and the octanuclear cluster U8Cl24O4(cp*py)2 [cp*py is tetramethyl‐5‐(2‐pyridyl)cyclopentadiene]

In bis­[1,1′,2,2′,3,3′,4,4′‐octa­methyl‐5‐(2‐pyridinio)‐5′‐(2‐pyri­dyl)­ferrocene] di‐μ₃‐chloro‐hexadeca‐μ₂‐chloro‐hexa­chloro­di‐μ₄‐oxo‐di‐μ₃‐oxo‐bis­[(η⁵,κN)‐1,2,3,4‐tetra­methyl‐5‐(2‐pyridyl)­cyclo­penta­dienyl]octauranium(IV) di­chloro­methane tetrasolvate, [Fe(C₁₄H₁₇N)(C₁₄H₁₆N)]₂[U₈Cl₂₄O₄(C₁₄H₁₆N)₂]·4CH₂Cl₂, (I), two protonated Fe(cp*py)₂ units [cp*py is tetra­methyl‐5‐(2‐pyridyl)­cyclo­penta­diene] form an ion pair with the dianionic centrosymmetric cluster U₈Cl₂₄O₄(cp*py)₂. The latter is the highest nuclearity assemblage in the chemistry of uranium (non‐uranyl) compounds reported to date.