Acetonitrile Disolvate Research Articles

Synthesis and crystal structure of an iron triazole complex resulting from the unexpected ligand cleavage of a triazolium carbene precursor.

Typically reactions of N-heterocyclic carbenes with transition metals are straightforward and require a carbene salt, a base strong enough to deprotonate such a salt and a metal. Yet when carbene precursors are in the form of triazolium salts, reaction may not proceed as easily as expected. In our work, we intended to obtain a triazolylidene complex of iron(II) chloride, but due to the presence of small amounts of water in the tetrahydrofuran solvent used, bis(acetonitrile)tetrakis(1-benzyl-1H-1,2,4-triazole-κN4)iron(II) μ-oxido-bis[trichloridoferrate(III)] acetonitrile disolvate, [Fe(C9H9N3)4(CH3CN)2][Fe2Cl6O]·2CH3CN - an interesting anion with a linear geometry of the O atom - was formed instead of the iron carbene complex. Reaction proceeded via cleavage of the alkyl N-substituent of the triazolium salt. The formation of the product was confirmed by X-ray crystallography. The crystal structure and possible reaction pathways are discussed.

Ethidium tetra-phenyl-borate aceto-nitrile disolvate.

In the title solvated salt, (C21H20N3){B(C6H5)4}·2CH3CN (systematic name 3,8-di-amino-5-ethyl-6-phenyl-phenanthridin-5-ium tetra-phenyl-borate aceto-nitrile disolvate), the dihedral angle between the tricyclic fused ring system (r.m.s. deviation = 0.021 Å) and the pendant phenyl group of the ethidium cation is 84.91 (7)°. The {B(C6H5)4}- anion has a typical tetra-hedral structure. The aceto-nitrile solvent mol-ecules do not accept hydrogen bonds from the -NH2 groups of the ethidium ions.

Syntheses and crystal structures of the ethanol, acetonitrile and diethyl ether Werner clathrates bis-(iso-thio-cyanato-κN)tetra-kis-(3-methyl-pyridine-κN)nickel(II).

The reaction of nickel(II)thio-cyanate with 3-methyl-pyridine (3-picoline; C6H7N) in different solvents leads to the formation of crystals of bis-(iso-thio-cyanato-κN)tetra-kis-(3-methyl-pyridine-κN)nickel(II) as the ethanol disolvate, [Ni(NCS)2(C6H7N)4]·2C2H5OH (1), the acetonitrile disolvate, [Ni(NCS)2(C6H7N)4]·2CH3CN (2), and the diethyl ether monosolvate, [Ni(NCS)2(C6H7N)4]·C4H10O (3). The crystal structures of these compounds consist of NiII cations coordinated by two N-bonded thio-cyanate anions and four 3-methyl-pyridine ligands to generate NiN6 octa-hedra with the thio-cyanate groups in a trans orientation. In compounds 1 and 2 these complexes are located on centers of inversion, whereas in compound 3, they occupy general positions. In the crystal structures, the complexes are packed in such a way that cavities are formed in which the solvent mol-ecules are located. Compounds 1 and 2 are isotypic, which is not the case for compound 3. In compounds 1 and 2 the solvate mol-ecules are disordered, whereas they are fully ordered in compound 3. Disorder is also observed for one of the 3-methyl-pyridine ligands in compound 2. Powder X-ray diffraction and IR measurements show that at room temperature all compounds decompose almost immediately into the same phase, as a result of the loss of the solvent mol-ecules.

Syntheses and crystal structures of a new pyrazine dicarboxamide ligand, N 2,N 3-bis-(quinolin-8-yl)pyrazine-2,3-dicarboxamide, and of a copper perchlorate binuclear complex.

The title pyrazine dicarboxamide ligand, N 2,N 3-bis-(quinolin-8-yl)pyrazine-2,3-dicarboxamide (H2L1), C24H16N6O2, has a twisted conformation with the outer quinoline groups being inclined to the central pyrazine ring by 9.00 (6) and 78.67 (5)°, and by 79.94 (4)° to each other. In the crystal, molecules are linked by C-H⋯O hydrogen bonds, forming layers parallel to the (10) plane, which are in turn linked by offset π-π inter-actions [inter-centroid distances 3.4779 (9) and 3.6526 (8) Å], forming a supra-molecular three-dimensional structure. Reaction of the ligand H2L1 with Cu(ClO4)2 in aceto-nitrile leads to the formation of the binuclear complex, [μ-(3-{hy-droxy[(quinolin-8-yl)imino]-meth-yl}pyrazin-2-yl)[(quinolin-8-yl)imino]-methano-lato]bis-[diaceto-nitrile-copper(II)] tris-(per-chlor-ate) aceto-nitrile disolvate, [Cu2(C24H15N6O2)(CH3CN)4](ClO4)3·2CH3CN or [Cu2(HL1-)(CH3CN)4](ClO4)3·2CH3CN (I). In the cation of complex I, the ligand coordinates to the copper(II) atoms in a bis-tridentate fashion. A resonance-assisted O-H⋯O hydrogen bond is present in the ligand; the position of this H atom was located in a difference-Fourier map. Both copper(II) atoms are fivefold coordinate, being ligated by three N atoms of the ligand and by the N atoms of two aceto-nitrile mol-ecules. The first copper atom has a perfect square-pyramidal geometry while the second copper atom has a distorted shape. In the crystal, the cation and perchlorate anions are linked by a number of C-H⋯O hydrogen bonds, forming a supra-molecular three-dimensional structure.

Bond length of perchlorate at different temperatures: X-ray and neutron comparison.

The averages (average deviations from the mean are given in square brackets) of uncorrected Cl-O bond distances in a perchlorate anion from an X-ray diffraction analysis of (N-{2-[bis(pyridin-2-ylmethyl)amino]ethyl}pyridine-2-carboxamidato)(nitric oxide)manganese perchlorate acetonitrile disolvate, [Mn(C20H20N5O)(NO)]ClO4·2CH3CN or [Mn(PaPy3)(NO)]ClO4·2CH3CN, decrease from 1.447 [4] Å at 10 K to 1.428 [4] Å at 170 K. The 10 K value is close to the neutron value (1.441 [1] Å) at 18 K. Comparisons are made with a second X-ray study at 30 K [1.444 (8) Å] and to libration-corrected, density functional theory (DFT), and Cambridge Structural Database (CSD) values.

9-(3,5-Dimethylbenzylidene)-8-(3,5-dimethylphenyl)-1,3,5,7-tetraphenyl-2,4,7,8-tetrahydro-4,7-methanoazulene acetonitrile disolvate

The title Diels–Alder product, C52H44·2CH3CN, was obtained in trace quantity as the `endo' isomer during the synthesis of 1,3-diphenyl-6-(3,5-dimethylphenyl)fulvene. One of the two co-crystallized acetonitrile molecules is linked to the main molecule by a weak C—H...N hydrogen bond.

A halide-free pyridinium-substituted η3-cycloheptatrienide-Pd complex.

We report the synthesis and characterization of a novel 4-(dimethylamino)pyridinium-substituted η3-cycloheptatrienide-Pd complex which is free of halide ligands. Diacetonitrile{η3-[4-(dimethylamino)pyridinium-1-yl]cycloheptatrienido}palladium(II) bis(tetrafluoroborate), [Pd(C2H3N)2(C14H16N2)](BF4)2, was prepared by the exchange of two bromide ligands for noncoordinating anions, which results in the empty coordination sites being occupied by acetonitrile ligands. As described previously, exchange of only one bromide leads to a dimeric complex, di-μ-bromido-bis({η3-[4-(dimethylamino)pyridinium-1-yl]cycloheptatrienido}palladium(II)) bis(tetrafluoroborate) acetonitrile disolvate, [Pd2Br2(C14H16N2)2](BF4)2·2CH3CN, with bridging bromide ligands, and the crystal structure of this compound is also reported here. The structures of the cycloheptatrienide ligands of both complexes are analogous to the dibromide derivative, showing the allyl bond in the β-position with respect to the pyridinium substituent. This indicates that, unlike a previous interpretation, the main reason for the formation of the β-isomer cannot be internal hydrogen bonding between the cationic substituents and bromide ligands.

Design, synthesis, crystal structure and in vitro cytotoxic properties of a novel Schiff base derived from indole and biphenyl.

A novel and potentially active dihydroorotate dehydrogenase (DHODH) inhibitor, namely 3-({(E)-[(E)-1-(biphenyl-4-yl)ethylidene]hydrazinylidene}methyl)-1H-indole (BEHI) acetonitrile disolvate, C23H19N3·2CH3CN, has been designed and synthesized. The structure of BEHI was characterized by elemental analysis, Q-TOF (quadrupole time-of-flight) MS, NMR, UV-Vis and single-crystal X-ray diffraction. The antitumour activity of the target molecule was evaluated by the MTT method. Results indicated that BEHI exhibited rather potent cytotoxic activity against human A549 (IC50 = 20.5 µM) and mouse breast 4T1 (IC50 = 18.5 µM) cancer cell lines. Meanwhile, to rationalize its potencies in the target, BEHI was docked into DHODH and the interactions with the active site residues were analyzed. Single-crystal structure analysis indicated that hydrogen bonds are present only between BEHI and acetonitrile solvent molecules in the asymmetric unit. The interplay of weak π-π stacking and weak C(N)-H...π interactions between neighbouring BEHI molecules play crucial roles in the formation of the final supramolecular frameworks.

1–9-NαC]-Linusorb B3 (cyclolinopeptide A) acetonitrile disolvate

The title compound, C57H85N9O9·2C2H3N [systematic name:cyclo-(prolyl-prolyl-phenylalanyl-phenylalanyl-leucyl-isoleucyl-isoleucylleucyl-valyl) acetonitrile disolvate; synonym: cyclolinopeptide acetonitrile disolvate], is a polypeptide with nine amino acids,viz.NαC-(Pro1–Pro2–Phe3–Phe4–Leu5–Ile6–Ile7–Leu8–Val9). It was extracted from flaxseed oil and crystallized from acetonitrile as a disolvate. In the title molecule, there are four intramolecular N—H...O hydrogen bonds. One of the two acetonitrile molecules is hydrogen bonded to Phe3viaan N—H...N hydrogen bond, while the second acetonitrile molecule is located at the other side of the peptide ring and is linked to the title molecule by a C—H...N hydrogen bond. In the crystal, molecules are linked by N—H...O hydrogen bonds, forming chains along thea-axis direction. The chains are linked by C—H...O hydrogen bonds, forming undulating layers parallel to theacplane.

New homodinuclear tris(3-alkylpyrazolyl)borate complexes of CoII and NiII with a tetraacetylethane dianion as a bridging ligand.

Polynuclear complexes and coordination polymers of 3d metals have attracted significant interest evoked by a number of their unique properties. One of the most common approaches to the directed synthesis of coordination polymers is the linking of pre-prepared discrete coordination units by polydentate ligands. The formation of polynuclear complexes is usually a spontaneous process and precise prediction of the products of such reactions is virtually impossible in most cases. Tris(pyrazolyl)borates (Tp) act as tripodal `capping' ligands which form stable complexes with 3d metal ions. In such 1:1 compounds, three metal-ion coordination sites are occupied by N atoms from a Tp anion. This limits the number of remaining coordination sites, and thus the number of additional ligands which may coordinate, and opens an attractive approach for the directed design of desirable structures by exploiting ligands with appropriate composition and topology. In the present study, Tp anions with neopentyl [TpNp, tris(3-neopentylpyrazolyl)borate] and cyclohexyl [TpCy, tris(3-cyclohexylpyrazolyl)borate] substituents were used as `capping' ligands and the dianion of tetraacetylethane (3,4-diacetylhexa-2,4-diene-2,5-diolate, tae2-) was employed as a bridge. The dinuclear complexes (μ-3,4-diacetylhexa-2,4-diene-2,5-diolato-κ4O2,O3:O4,O5)bis{[tris(3-cyclohexyl-1H-pyrazol-1-yl-κN2)borato]cobalt(II)} acetonitrile disolvate, [Co2(C27H40BN6)2(C10H12O4)]·2CH3CN, (I)·2CH3CN, and (μ-3,4-diacetylhexa-2,4-diene-2,5-diolato-κ4O2,O3:O4,O5)bis{[tris(3-neopentyl-1H-pyrazol-1-yl-κN2)borato]nickel(II)}, [Ni2(C24H40BN6)2(C10H12O4)], (II), were synthesized by the reaction of the mononuclear complexes TpCyCoCl or TpNpNiCl with H2tae (3,4-diacetylhexane-2,5-dione or tetraacetylethane) in the presence of NEt3 as base. Compounds (I) and (II) were characterized by mass spectrometry, elemental analysis, and X-ray crystallography. They possess similar molecular structures, X-ray diffraction revealing them to be dinuclear in nature and composed of discrete Tp-M units in which two metal ions are linked by a tae2- dianion. Each metal ion possesses a five-coordinate square-pyramidal environment. The interplanar angles between the acetylacetonate fragments are significantly smaller than the near-90° values commonly observed.

An investigation of the electron density of a Jahn-Teller-distorted Cr(II) cation: the crystal structure and charge density of hexakis(acetonitrile-κN)chromium(II) bis(tetraphenylborate) acetonitrile disolvate.

In the crystal structure of the title homoleptic Cr(II) complex, [Cr(CH3CN)6](C24H20B)2·CH3CN, the [Cr(CH3CN)6](2+) cation is a high-spin d(4) complex with strong static, rather than dynamic, Jahn-Teller distortion. The electron density of the cation was determined by single-crystal X-ray refinements using aspherical structure factors from wavefunction calculations. The detailed picture of the electronic density allowed us to assess the extent and directionality of the Jahn-Teller distortion of the Cr(II) cation away from idealized octahedral symmetry. The topological analysis of the aspherical d-electron density about the Cr(II) cation showed that there are significant valence charge concentrations along the axial Cr-N axes. Likewise, there were significant valence charge depletions about the Cr(II) cation along the equatorial Cr-N bonds. These charge concentrations are in accordance with a Jahn-Teller-distorted six-coordinate complex.

Crystal structure of cis-anti-cis-di-cyclo-hexane-18-crown-6 aceto-nitrile disolvate.

The title compound (systematic name: cis-anti-cis-2,5,8,15,18,21-hexa­oxatri­cyclo­[20.4.0.09,14]hexa­cosane aceto­nitrile disolvate), C20H36O6·2CH3CN, crystallizes from an aceto­nitrile solution of di­cyclo­hexane-18-crown-6 on evaporation. The mol­ecule is arranged around a center of symmetry with half the crown ether mol­ecule and one mol­ecule of aceto­nitrile symmetry independent. All O—C—C—O torsion angles are gauche while all C—O—C—C angles are trans. The sequence of torsion angles is [(tg+t)(tg−t)]3; the geometry of oxygen atoms is close to pseudo-D 3d with three atoms below and three atoms above the mean plane, with an average deviation of ±0.16 (1) Å from the mean plane. This geometry is identical to that observed in metal ion complexes of di­cyclo­hexane-18-crown-6 but differs significantly from the conformation of a free unsolvated mol­ecule. Each aceto­nitrile mol­ecule connects to a crown ether mol­ecule via two of its methyl group H atoms (C—H⋯O). Weaker inter­actions exist between the third H atom of the aceto­nitrile methyl group and an O atom of a neighbouring crown ether mol­ecule (C—H⋯O); and between the N atom of the aceto­nitrile mol­ecule and a H atom of another neighbouring crown ether mol­ecule. All these inter­molecular inter­actions create a three-dimensional network stabilizing the disolvate.

Chlorido(4,4′-dimethoxy-2,2′-bipyridine)(1,4,7-trimethyl-1,4,7-triazacyclononane)ruthenium(II) perchlorate acetonitrile disolvate and aqua(4,4′-dimethoxy-2,2′-bipyridine)(1,4,7-trimethyl-1,4,7-triazacyclononane)ruthenium(II) bis(perchlorate) dihydrate

The title complexes, [RuCl(C(9)H(21)N(3))(C(12)H(12)N(2)O(2))]ClO(4)·2C(2)H(3)N, (I), and [Ru(C(9)H(21)N(3))(C(12)H(12)N(2)O(2))(H(2)O)](ClO(4))(2)·2H(2)O, (II), display similar structures with the Ru atom in a distorted octahedral environment. In the crystal packing of the chloride complex, (I), the Ru complex molecules are held together in pairs through C-H···Cl interactions of the 4,4'-dimethoxy-2,2'-bipyridine and chloride ligands. In the case of the aqua complex, (II), hydrogen bonding affords a tetrameric hydrogen-bonded network. These two structures are the first examples of complexes with the {Ru(1,4,7-trimethyl-1,4,7-triazacyclononane)} motif and an electron-rich substituted 2,2'-bipyridine ligand.

5,11,17,23,29,35-Hexa-tert-butyl-37,38,39,40,41,42-hexakis(ethoxycarbonylmethoxy)calix[6]arene acetonitrile disolvate

In the title compound, C90H120O18·2CH3CN, the calix[6]arene has a 1,2,3-alternate conformation and possesses inversion symmetry. It crystallizes as an acetonitrile disolvate, with a half-mol­ecule of calix[6]arene and one mol­ecule of solvent in the asymmetric unit. In the crystal, the two solvent mol­ecules are enclosed in voids between the calix[6]arene mol­ecules. They form weak C—H⋯O hydrogen bonds involving an O atom of the lower rim substituent. The cavity of the calix[6]arene itself is enclosed by two opposite phenol rings, which are turned into the cavity due to the presence of a C—H⋯π inter­action. The calix[6]arene mol­ecule exhibits disorder of one substituent on its lower rim [occupancy ratio 0.897 (3):0.103 (3)].

Rhodamine 6G hexa-chlorido-stannate(IV) acetonitrile disolvate.

In the title compound, bis({6-ethylamino-10-[2-(methoxycarbonyl)phenyl]-2,7-dimethylxanthen-3-ylidene}ethanaminium) hexachloridotin(IV) acetonitrile disolvate, (C27H29N2O3)2[SnCl6]·2C2H3N, the octa­hedral SnCl6 2− anion lies on an inversion center. The xanthene ring system is essentially planar, with an average deviation of 0.020 Å, and the substituent benzene ring forms a dihedral angle of 85.89 (2)° with it. The Sn—Cl distances are in the range 2.4237 (3)–2.4454 (3) Å. There are N—H⋯Cl hydrogen bonds between SnCl6 2− ions and rhodamine 6G cations as well as π–π stacking inter­actions between rhodamine 6G cations (inter­planar distance of 3.827 Å).

Bis[chloridobis(triphenylphosphine)copper(I)-μ-chlorido]bis(1,2-diaminopropane)copper(II) acetonitrile disolvate

The title complex [systematic name: bis­(1,2-diamino­propane-2κ2N,N′)di-μ-chlorido-1:2κ2Cl,2:3κ2Cl-dichlorido-1κCl,3κCl-tetra­kis(triphenyl­phosphine)-1κ2P,3κ2P-tricopper(I,II,I) acetonitrile disolvate], [{(Ph3P)2Cl2Cu}2Cu(C3H10N2)2]·2C2H3N, is a centrosymmetric linear trinuclear mixed-valence copper complex in which the central CuII atom is bridged by Cl atoms to the two CuI atoms. The coordination geometry is octa­hedral for CuII, with Jahn–Teller elongation of the Cu—Cl bonds, and distorted tetra­hedral for CuI, with a wide P—Cu—P angle. The diamine ligands are twofold disordered, with occupancy factors of ca 0.6:0.4, and form one N—H⋯Cl hydrogen bond each with a terminal Cl atom.

1,7-Bis(1,3-dimethyluracil-6-yl)-1,4,7,10-tetraazacyclododecane acetonitrile disolvate at 100 K

The title compound [systematic name: 1,1′,3,3′-tetra­methyl-1,1′,2,2′,3,3′,4,4′-octa­hydro-6,6-(1,4,7,10-tetra­azacyclo­dodec­ane-1,7-di­yl)dipyrimidine-2,2′,4,4′-tetra­one acetonitrile disolvate], C20H32N8O4·2CH3CN, an N-uracil-substituted cyclen derivative, is located on a crystallographic twofold rotation axis running through the center of the 12-membered ring and adopts a [3333] quadrangular conformation with C atoms occupying the corners.

The effect of hydrogen-bonding anions on the structure of metal–sulfimide complexes

Investigations into the effects of the choice of anion on the hydrogen-bonding interactions between anions and metal-sulfimide cationic complexes have led to the study of three novel compounds. Hexakis(S,S-diphenylsulfimide)cobalt(II) diiodide S,S-diphenylsulfimide acetonitrile disolvate, [Co(C12H11NS)6]I2.C12H11NS.2C2H3N, crystallizes in the centrosymmetric space group P-1 with Z = 2. Six diphenylsulfimide ligands coordinate to the cobalt centre through their N atoms. Two iodide counter-ions hydrogen bond to the cation through N-H...I interactions, with N...I distances in the range 3.7302 (19)-3.8461 (19) A. One extra molecule of sulfimide is included in the asymmetric unit, regardless of the metal-ligand ratio used in the synthesis, and this sulfimide molecule also hydrogen bonds to one of the iodide counter-ions through one N-H...I hydrogen bond. The reaction of FeCl3.6H2O with S,S-diphenylsulfimide monohydrate yields hexakis(S,S-diphenylsulfimide)iron(III) trichloride, [Fe(C12H11NS)6]Cl3. The complex crystallizes in the centrosymmetric cubic space group Pa-3 and the asymmetric unit contains one-sixth of a formula unit. Two of the chloride anions each hydrogen bond to three sulfimide NH groups on opposite sides of the [Fe(Ph2SNH)6]3+ cation. The third chloride anion does not take part in any strong hydrogen bonding; instead it is surrounded by aromatic groups and is involved in C-H...Cl hydrogen bonds. The reaction of [Pt(Ph2SNH)4]Cl2 with I2 facilitates oxidation of the Pt(II) metal centre to Pt(IV), producing tetrakis(S,S-diphenylsulfimide)diiodoplatinum(IV) dichloride dichloromethane disolvate, [PtI2(C12H11NS)4]Cl2.2CH2Cl2. The crystal structure is centrosymmetric, with the elongated octahedral cationic complex situated on an inversion centre. The chloride anions are hydrogen bonded to the cation through N-H...Cl hydrogen bonds, with two cis NH groups hydrogen bonded to each anion. Strong hydrogen bonding within these three compounds is limited to N-H...halide hydrogen bonds between the cation and two anions, with a three-up/three-down arrangement of the NH groups in the first two compounds. The anions also 'cap' the NH groups in the third compound. In all three cases, the anions are also involved in weaker hydrogen bonds utilizing the plethora of relatively acidic aryl CH groups in the structures.

A dinuclear nickel(II) complex of the ligand 2,6-bis[2-(dimethylamino)ethyliminomethyl]-4-methylphenol

In the title complex, triaqua{μ-2,6-bis[2-(dimethylamino)ethyliminomethyl]-4-methylphenolato}-μ-bromo-bromodinickel(II) bromide monohydrate acetonitrile disolvate, [Ni2Br2(C17H27N4O)(H2O)3]Br·H2O·2C2H3N, the NiII atoms are octahedrally coordinated and the donor groups are different (N2O3Br and N2O2Br2), with an intermetallic separation of 3.2346 (9) A.