Platinum complexes of oxopurines: cis‐bis(theophyllinato‐N7)bis(triphenylphosphine)platinum(II) and cis‐chloro(theobrominato‐N1)bis(triphenylphosphine)platinum(II) ethanol hemisolvate

The syntheses and structures of two mixed‐ligand complexes of platinum(II) with deprotonated oxopurine bases and tri­phenyl­phosphine are reported, namely the theophyllinate complex cis‐bis(1,2,3,6‐tetra­hydro‐1,3‐di­methyl­purine‐2,6‐dionato‐κN⁷)­bis(tri­phenyl­phosphine‐κP)­platinum(II), [Pt(C₇H₇N₄O₂)₂(C₁₈H₁₅P)₂], (I), and the theobrominate complex cis‐chloro(1,2,3,6‐tetrahydro‐3,7‐dimethylpurine‐2,6‐dionato‐κN¹)­bis(tri­phenyl­phosphine‐κP)­platinum(II) ethanol hemisolvate, [PtCl(C₇H₇N₄O₂)(C₁₈H₁₅P)₂]·0.5C₂H₅OH, (II). In (I), the coordination geometry of Pt is square planar, formed by the two coordinating N atoms of the theophyl­linate anions in a cis arrangement and two P atoms from the tri­phenyl­phosphine groups. In (II), there are two crystallographically independent mol­ecules. They both exhibit a square‐planar coordination geometry around Pt involving one Cl atom, the coordinating N atom of the theobrominate anion and two P atoms from the tri­phenyl­phosphine groups. The two tri­phenyl­phosphine groups are arranged in a cis configuration in both structures. The heterocyclic rings are rotated with respect to the coordination plane of the metal by 82.99 (8) and 88.09 (8)° in complex (I), and by 85.91 (16) and 88.14 (18)° in complex (II). Both structures are stabilized by intramolecular stacking interactions involving the purine rings and the phenyl rings of adjacent tri­phenyl­phosphine moieties.     

Double‐helix pattern in a model compound of non‐linear optical polymers

Mol­ecules of the title compound, 3,3′‐[4‐(4‐nitro­phenyl­diazenyl)phenyl­imino]dipropionic acid, C₁₈H₁₈N₄O₆, a model compound of second‐order non‐linear optically active polymers, form helicoidal rows via hydrogen bonding between carboxy groups. Pairs of helices are wrapped around the common axis in a double‐helix arrangement unprecedented in dicarboxylic acids. The lateral packing of the helices shows an inter­digitated anti­parallel arrangement of the chromophore units.     

l‐Phenyl­alanine–4‐nitro­phenol (1/1)

In the 1:1 adduct formed between l ‐phenyl­alanine and 4‐nitro­phenol [alternative IUPAC name: (2S)‐2‐ammonio‐3‐phenyl­propanoate–4‐nitro­phenol (1/1)], C₉H₁₁NO₂·C₆H₅NO₃, the l ‐phenyl­alanine mol­ecule is in the zwitterionic state. The overall structure is stabilized via strong hydrogen bonding between polar zones and van der Waals inter­actions between non‐polar zones, which alternate with the polar zones.     

The 1:1 cocrystals of the proton‐transfer compound dilituric acid–phenyl­biguanide monohydrate

A proton‐transfer compound, 1‐phenyl­biguanidium 5‐nitro‐2,6‐dioxo‐1,2,3,6‐tetra­hydro­pyrimidin‐4‐olate monohydrate, C₈H₁₂N₅⁺·C₄H₂N₃O₅⁻·H₂O, has been synthesized by a reaction between dilituric acid (5‐nitro‐2,4,6‐trihydroxy­pyrimi­dine, Dilit) and phenyl­biguanide (N‐phenyl­imido­carbonimidic diamide, Big). This compound cocrystallized as a 1:1 adduct, and the asymmetric unit consists of two dilituric amino–oxo planar tautomeric anions (Dilit⁻), two monoprotonated phenyl­biguanidium cations (BigH⁺) and two water mol­ecules of crystallization (Z′ = 2). Protonation occurs at the N atom attached to the phenyl ring of Big as a result of the proton‐transfer process from the acidic hydr­oxy group of Dilit. In the crystal structure, the hydrated 1:1 adduct is stabilized by 25 two‐ and three‐center hydrogen bonds.     

The first metalloporphyrin dimer linked by a bridging phenylenedicarbene ligand

In the first bis­[ruthenium(II)–porphyrin]–dicarbene complex, μ‐[1,4‐phenyl­ene­bis(phenyl­methyl­idene‐κC)]bis­[(ethanol‐κO)(5,10,15,20‐tetra‐p‐tolyl­porphyrinato‐κ⁴N)ruthenium(II)] 1,2‐di­chloro­ethane trisolvate, [Ru₂(C₂₀H₁₄)(C₄₈H₃₆N₄)₂(C₂H₆O)₂]·3C₂H₄Cl₂, an inversion center is located at the center of the μ‐phenyl­ene group, leading to a parallel arrangement for the pair of porphyrin ring systems. The bond lengths and angles compare favourably with literature values for ruthenium–porphyrin–monocarbene complexes; the Ru=C(carbene) bond length and the C(phenyl)—C(carbene)—C(phenyl­ene) angle are 1.865 (3) Å and 112.3 (3)°, respectively. The Ru^II ion is displaced out of the C₂₀N₄ porphyrin least‐squares plane (by 0.2373 Å) toward the bridging ligand of the C_i‐symmetry dimer. The porphyrin ring systems of the dimer thus exhibit mildly domed conformations.     

Ammonium 4‐nitrophenylarsonate

In the crystal structure of the title compound, (NH₄)[AsO₂(OH)(C₆H₄NO₂)], the 4‐nitro­phenyl­arsonate anions and ammonium cations are linked through hydrogen bonds to form infinite chains along the b axis. The hydroxyl O atom of the 4‐nitro­phenyl­arsonate anion acts as both an acceptor and a donor of hydrogen bonds. All atoms are located in general positions.     

A new optically pure half‐sandwich Cp–Ru diphosphine complex with a chiral metal centre, (S)‐Ru(η5‐C5H5)(EPHOS)Cl {EPHOS is (+)‐(1R,2S)‐2‐[(diphenylphosphino)methylamino]‐1‐phenylpropyl diphenylphosphinite}

The crystal structure of the title compound, chloro(η⁵‐cyclopenta­dienyl){(1R,2S)‐2‐[(di­phenyl­phosphino)­methyl­amino]‐1‐phenyl­propyl di­phenyl­phosphinite‐κ²P,P′}ruthenium(II), [Ru(C₅H₅)Cl(C₃₄H₃₃NOP₂)], is reported. The pseudo‐octa­hedral complex is chiral and the configuration at the Ru atom is S. The seven‐membered metallacycle adopts a boat‐like conformation.     

[Ethylene-1,2-bis(diphenylphosphine)-P,P′]dinitratoplatinum(II) and cis-bis[(diphenylphosphinomethyl)diphenylphosphine oxide-O,P]platinum(II) dinitrate dihydrate

In [Pt(dppe)(NO₃)₂], where dppe is ethyl­ene-1,2-bis­(di­phenyl­phosphine) (C₂₆H₂₄P₂), the Pt atom is coordinated by the two P atoms and by two O atoms of the two nitrate ions. The mol­ecule has a distorted square-planar geometry, with one of the nitrate groups directed on each side of the plane. The cation in cis-[Pt(dppmO-O,P)₂](NO₃)₂·2H₂O, where dppmO is bis­(di­phenyl­phosphino­methyl)­di­phenyl­phosphine oxide (C₂₅H₂₂OP₂), comprises two five-membered chelate rings, each dppmO ligand being coordinated to platinum through one P atom and the O atom. The larger P—Pt—P angle of 102.25 (4)° is due to steric interactions between the two phenyl groups on each P atom.     

2,4‐Di­nitro­phenyl­hydrazones of 2,4‐di­hydroxy­benz­aldehyde, 2,4‐di­hydroxy­aceto­phenone and 2,4‐di­hydroxy­benzo­phenone

In 2,4‐di­hydroxy­benz­aldehyde 2,4‐di­nitro­phenyl­hydrazone N,N‐di­methyl­form­amide solvate {or 4‐[(2,4‐di­nitro­phenyl)­hydrazono­methyl]­benzene‐1,3‐diol N,N‐di­methyl­form­amide solvate}, C₁₃H₁₀N₄O₆·C₃H₇NO, (X), 2,4‐di­hydroxy­aceto­phenone 2,4‐di­nitro­phenyl­hydrazone N,N‐di­methyl­form­am­ide solvate (or 4‐{1‐[(2,4‐di­nitro­phenyl)hydrazono]ethyl}benzene‐1,3‐diol N,N‐di­methyl­form­amide solvate), C₁₄H₁₂N₄O₆·C₃H₇NO, (XI), and 2,4‐di­hydroxy­benzo­phenone 2,4‐di­nitro­phenyl­hydrazone N,N‐di­methyl­acet­amide solvate (or 4‐­{[(2,4‐di­nitro­phenyl)hydrazono]phenyl­methyl}benzene‐1,3‐diol N,N‐di­methyl­acet­amide solvate), C₁₉H₁₄N₄O₆·C₄H₉NO, (XII), the molecules all lack a center of symmetry, crystallize in centrosymmetric space groups and have been observed to exhibit non‐linear optical activity. In each case, the hydrazone skeleton is fairly planar, facilitated by the presence of two intramolecular hydrogen bonds and some partial N—N double‐bond character. Each molecule is hydrogen bonded to one solvent mol­ecule.     

A new chain‐like cadmium(II) coordination polymer containing chains of water mol­ecules

The title cadmium(II) polymer, catena‐poly[[[bis­(4‐amino­pyridine‐κN)­aqua­cadmium(II)]‐μ‐1,4‐phenyl­enediacetato‐κ⁴O,O′:O′′,O′′′] dihydrate], {[Cd(C₁₀H₈O₄)(C₅H₆N₂)₂(H₂O)]·2H₂O}_n, comprises one‐dimensional wave‐like chains, in which the Cd atom is coordinated by 1,4‐phenyl­enediacetate and 4‐amino­pyridine molecules. The 1,4‐phenylenediacetate ligands lie about inversion centres. Extensive hydrogen‐bonding inter­actions between the chains lead to a three‐dimensional structure. Free water mol­ecules form chains in the structure.     

(4‐Nitrophenylsulfanylmethyl)triphenylstannane and (4‐nitrophenylsulfonylmethyl)triphenylstannane: R(X) rings (X is 10, 18 or 24) and C—H⋯π interactions

In the crystal structures of (4‐nitro­phenyl­sulfanyl­methyl)­tri­phenyl­stannane, [Sn(C₆H₅)₃(C₇H₆NO₂S)], (I), and (4‐nitro­phenyl­sulfonyl­methyl)­tri­phenyl­stannane, [Sn(C₆H₅)₃­(C₇H₆NO₄S)], (II), the mol­ecules are linked by paired C—H?O hydrogen bonds into centrosymmetric dimers which combine to form sheets. In (I), two such dimers form to give R(10) and R(24) rings. In (II), similar dimers form, here with R(10) and R(18) rings, but with an additional dimer due to the presence of the sulfone group, giving R(10) rings. In both structures, C—H?π interactions lead to a doubling of the width of the sheets.     

N‐[tert‐Butoxy­carbonyl­glycyl‐(Z)‐α,β‐dehydro­phenyl­alanylglycyl‐(E)‐α,β‐dehydro­phenyl­alanylphenyl­alanyl]‐4‐nitro­aniline ethanol solvate

The α,β‐dehydro­phenyl­alanine residues influence the conformation of the title penta­peptide Boc⁰–Gly¹–Δ^ZPhe²–Gly³–Δ^EPhe⁴–l ‐Phe⁵–p‐NA ethanol solvate, C₄₂H₄₃N₇O₉·C₂H₅OH. The first unsaturated phenyl­alanyl (Δ^ZPhe²) and the third glycyl (Gly³) residues form a type I β turn, while the second unsaturated phenyl­alanyl (Δ^EPhe⁴) and the last phenyl­alanyl (l ‐Phe⁵) residues are part of a type II β turn. All the amino acids in the peptide are linked trans to one another. The crystal structure is stabilized by intra‐ and inter­molecular hydrogen bonds.     

Two derivatives of (N‐phenylthioureidoalkyl)phosphonates

The structures of di­phenyl [3‐methyl‐1‐(3‐phenyl­thio­ureido)­butyl]­phosphonate and di­phenyl [2‐methyl‐1‐(3‐phenyl­thio­ureido)­butyl]­phosphonate, both C₂₄H₂₇N₂O₃PS, are reported. In both compounds, the thio­urea moiety adopts a syn–syn conformation (i.e. the S—C—N—C torsion angles are synperi­planar), which enables N—H⋯O hydrogen bonds to be formed between centrosymmetrically related mol­ecules. The geometries around the P atoms can be described as distorted tetrahedral. Some of the functional groups in each structure are disordered. The bulk of the different alkyl substituents between the amide and phosphonate groups influences the molecular conformation and crystal packing. Although the structures of these compounds and two related derivatives appear to be similar, they are not isostructural.     

Astemizole tetra­chloro­cuprate(II)

The structure of {3‐[(4‐fluoro­phenyl)­methyl]‐1H‐benzimidazol‐2‐ylidene}{1‐[2‐(4‐meth­oxy­phenyl)­ethyl]‐4‐piperidin‐1‐io}ammonium tetra­chloro­cuprate(II), (C₂₈H₃₃FN₄O)[CuCl₄], contains diprotonated cations of astemizole hydrogen bonded to three Cl atoms in two different CuCl₄^2? anions, with Cl?N distances in the range 3.166 (4)–3.203 (4) Å. The geometry around copper is flattened tetrahedral with significantly different Cu—Cl distances which lie in the range 2.1968 (14)–2.2861 (12) Å. The phenyl­ethyl C atoms of the (4‐methoxy­phenyl­)ethyl group are disordered indicating the presence of two conformers in the crystals.     

Two 2,2‐dihalo‐N‐(1‐phenyl­ethyl)­cyclo­propane‐1‐carbox­amides

The crystal structures of (1R,1′S)‐2′,2′‐di­chloro‐N‐(1‐phenyl­ethyl)­cyclo­propane‐1′‐carbox­amide, C₁₂H₁₃Cl₂NO, (I), and (1R,1′R)‐2′,2′‐di­fluoro‐N‐(1‐phenyl­ethyl)­cyclo­propane‐1′‐car­box­amide, C₁₂H₁₃F₂NO, (II), have been determined. Both crystals contain two independent mol­ecules with different conformations of the phenyl­ethyl groups. In the crystals of both compounds, the mol­ecules are linked together by N—H⃛O hydrogen bonds, thus forming chains in the a direction.     

A ruthenium(II)–porphyrin–carbene complex with a weakly bonded methanol ligand

The title di­phenyl­carbene porphyrin complex (di­phenyl­carbenyl‐κC)(methanol‐κO)(5,10,15,20‐tetra‐p‐tolyl­por­phy­rin­ato‐κ⁴N)ruthenium(II) methanol solvate, [Ru­(C₁₃H₁₀)(C₄₈H₃₆N₄)(CH₄O)]·CH₄O, has a six‐coordinate Ru atom with a methanol mol­ecule as the second axial ligand. The carbene fragment is slightly distorted from an ideal sp² configuration, with a C(phenyl)—C(carbene)—C(phenyl) angle of 112.2 (3)°. The Ru—C bond length of 1.845 (3) Å is comparable with other carbene complexes. The two phenyl rings of the carbene ligand are perpendicular to the carbene plane. Methanol solvate mol­ecules link the methanol ligands of adjacent porphyrin complexes via hydrogen bonds.     

A novel nickel(II) coordination polymer incorporating 1,4‐phenylene­diacetic acid and 1,10‐phenanthroline

The title nickel(II) coordination polymer, viz. poly[[bis­(1,10‐phenanthroline)tris­(μ₃‐1,4‐phenyl­enediacetato)trinickel(II)] dihydrate], {[Ni₃(C₁₀H₈O₄)₃(C₁₂H₈N₂)₂]·2H₂O}_n, consists of linear trinuclear building blocks with two crystallographically unique Ni atoms. One Ni^II atom and the geometric centre of one 1,4‐phenyl­enediacetate ligand in the trinuclear unit both lie on inversion centres, while the other unique Ni^II atom lies near the inversion centre, together with another 1,4‐phenyl­enediacetate ligand. Each pair of adjacent trinuclear units is bridged by 1,4‐phenyl­enediacetate ligands, forming two kinds of infinite chains along the a and b axes, respectively. These two kinds of chains crosslink to yield a two‐dimensional network in the ab plane. The two‐dimensional sheets further stack along the c axis viaπ–π stacking inter­actions and hydrogen bonds, forming a three‐dimensional supramolecular structure.     

A dimeric layered structure of a 4‐oxo‐4,5‐di­hydro‐1H‐pyrazolo­[3,4‐d]­pyrimidine compound

The title compound, 6‐methyl­sulfanyl‐1‐(3‐phenyl­propyl)‐4,5‐di­hydro‐1H‐pyrazolo­[3,4‐d]­pyrimidin‐4‐one, C₁₅H₁₆N₄OS, crystallizes in space group Pbca, with two mol­ecules of similar structure in the asymmetric unit. The molecular structure shows the absence of intramolecular stacking in the crystalline state, as indicated by earlier ¹H NMR analysis in solution. In addition, the crystal packing reveals the formation of a layered structure, due mainly to intermolecular N—H?O=C hydrogen bonding and arene–arene interactions.     

cis‐(6RS,13RS)‐3,3,10,10‐Tetra­methyl‐6,13‐diphenyl‐1,8‐dioxa‐4,11‐diaza­cyclo­tetra­decane‐2,5,9,12‐tetra­one and two of its precursors

The title macrocycle, C₂₆H₃₀N₂O₆, (VI), was obtained by `direct amide cyclization' from the linear precursor 3‐hydr­oxy‐N‐[1‐methyl‐1‐(N‐methyl‐N‐phenyl­carbamoyl)ethyl]‐2‐phenylpropanamide, the N‐methyl­anilide of rac‐2‐methyl‐2‐[(3‐hydroxy‐2‐phenyl­propanoyl)­amino]­propanoic acid, C₁₃H₁₇NO₄, (IV). The reaction proceeds via the inter­mediate rac‐2‐(2‐hydroxy‐1‐phenyl­ethyl)‐4,4‐dimethyl‐1,3‐oxazol‐5(4H)‐one, C₁₃H₁₅NO₃, (V), which was synthesized independently and whose structure was also established. Unlike all previously described analogues, the title macrocycle has the cis‐diphenyl configuration. The 14‐membered ring has a distorted rect­angular diamond‐based [3434] configuration and inter­molecular N—H⋯O hydrogen bonds link the mol­ecules into a three‐dimensional framework. The propanoic acid precursor forms a complex series of inter­molecular hydrogen bonds, each of which involves pairwise association of mol­ecules and which together result in the formation of extended two‐dimensional sheets. The oxazole inter­mediate forms centrosymmetric hydrogen‐bonded dimers in the solid state.     

Preference for the Diels–Alder addition of dienes syn to the O atom in cross‐conjugated spiro­cyclic cyclo­hexadienones

In the Diels–Alder reaction, the preferred addition of dienes syn to the O atom in cross‐conjugated cyclo­hexadienones containing an oxa‐­spiro ring system is observed. The two structures reported here, namely rel‐(1R,4aR,9S,9aS,10R)‐4a,9,9a,10‐tetra­hydro‐9,10‐di­phenyl­spiro­[9,10‐epoxy­anthra­cene‐1(4H),2′‐oxiran]‐4‐one, C₂₇H₂₀O₃, and rel‐(1R,4aS,9R,9aS,10S)‐4a,9,9a,10‐tetra­hydro‐9,10‐di­phenyl­spiro­[9,10‐epoxy­anthracene‐1(4H),2′‐oxetane]‐4‐one, C₂₈H₂₂O₃, are the minor and sole products, respectively, of the reactions of di­phenyl­isobenzo­furan with two slightly different cyclo­hexadienones. These structures differ in the size of the oxa‐­spiro ring, by one C atom, and in the relative configuration at the spiro­cyclic ring C atom, leading to some minor conformational differences between the two compounds.