Diethyl Ether Solvent Mol-ecule Research Articles

Synthesis and crystal structure of a PdII complex of ortho-xylylenebis(pyridyl-triazole).

A tetra-dentate ligand, namely, ortho-xylylenebis(pyridyl-triazole), o-xpt, was synthesized using the 'click' method and complexed with Pd(BF4)2. In the title com-plex, bis-{μ-1,1'-(o-xylylene)bis-[4-(pyridin-2-yl)triazole]-κN 3:N 3'}dipalladi-um(II) tetra-kis-(tetrafluoridoborate)-di-methyl-formamide-diethyl ether (1/2/1), as the BF4 salt, and including di-methyl-formamide and diethyl ether solvent mol-ecules, with stoichiometry [Pd2(C22H18N8)2](BF4)4·2C3H7NO·C4H10O, the Pd complex and the disordered diethyl ether mol-ecule lie on inversion centers. The ligand coordinates to the PdII centers with square-planar geometry, forming a dimeric macrocycle. The Pd⋯Pd separation in the complex [Pd2(o-xpt)2]4+ cation is 3.6184 (4) Å. In the crystal, the complex mol-ecules are stacked along the b axis, with π-π inter-actions between the pyridyl-triazole ligands of two mol-ecules.

Fixation of Dinitrogen at an Asymmetric Binuclear Titanium Complex.

A new type of dititanium dinitrogen complex supported by a triphenolamine (TPA) ligand is reported. Analysis by single-crystal X-ray diffraction and Raman and NMR spectroscopy reveals different coordination geometries for the two titanium centers. Hence, coordination of TPA and a nitrogen ligand results in trigonal-bipyramidal geometry, while an octahedral titanium center is obtained upon additional coordination of an ethoxide generated upon C-O bond cleavage in a diethyl ether solvent molecule. The titanium complex successfully generates ammonia in the presence of an excess amount of PCy3HI and KC8 in 154% yield (per titanium atom). A titanium complex with a bulkier TPA does not form a dinitrogen complex, and mononuclear titanium dinitrogen complexes were not accessible, presumably because of the high tendency of early transition metals to form binuclear dinitrogen complexes.

Unexpected reactions of NHC*-CuI and -AgI bromides with potassium thio- or seleno-cyanate.

The reactions of N-heterocyclic carbene CuI and AgI halides with potassium thio- or seleno-cyanate gave unexpected products. The attempted substitution reaction of bromido-(1,3-dibenzyl-4,5-di-phenyl-imidazol-2-yl-idene)silver (NHC*-Ag-Br) with KSCN yielded bis-[bis-(1,3-dibenzyl-4,5-di-phenyl-imidazol-2-yl-idene)silver(I)] tris-(thio-cyanato)-argentate(I) diethyl ether disolvate, [Ag(C29H24N2)2][Ag(NCS)3]·2C4H10O or [NHC*2Ag]2[Ag(SCN)3]·2Et2O, (1), while reaction with KSeCN led to bis-(μ-1,3-dibenzyl-4,5-diphenyl-2-seleno-imidazole-κ2 Se:Se)bis-[bromido-(1,3-dibenzyl-4,5-diphenyl-2-seleno-imid-azole-κSe)silver(I)] di-chloro-methane hexa-solvate, [Ag2Br2(C29H24N2Se)4]·6CH2Cl2 or (NHC*Se)4Ag2Br2·6CH2Cl2, (2), via oxidation of the NHC* fragment to 2-seleno-imidazole. This oxidation was observed again in the reaction of NHC*-Cu-Br with KSeCN, yielding catena-poly[[[(1,3-dibenzyl-4,5-diphenyl-2-seleno-imidazole-κSe)copper(I)]-μ-cyanido-κ2 C:N] aceto-nitrile monosolvate], {[Cu(CN)(C29H24N2Se)]·C2H3N} n or NHC*Se-CuCN·CH3CN, (3). Compound (1) represents an organic/inorganic salt with AgI in a linear coordination in each of the two cations and in a trigonal coordination in the anion, accompanied by diethyl ether solvent mol-ecules. The tri-blade boomerang-shaped complex anion [Ag(SCN)3]2- present in (1) is characterized by X-ray diffraction for the first time. Compound (2) comprises an isolated centrosymmetric mol-ecule with AgI in a distorted tetra-hedral BrSe3 coordination, together with di-chloro-methane solvent mol-ecules. Compound (3) exhibits a linear polymeric 1 ∞[Cu-C≡N-Cu-] chain structure with a seleno-imidazole moiety additionally coordinating to each CuI atom, and completed by aceto-nitrile solvent mol-ecules. Electron densities associated with an additional ether solvent mol-ecule in (1) and two additional di-chloro-methane solvent mol-ecules in (2) were removed with the SQUEEZE procedure [Spek (2015 ▸). Acta Cryst. C71, 9-18] in PLATON.

A triangular palladium(II) supramolecular coordination complex based on 1,4-bis(1H-imidazol-1-yl)benzene and (2,2'-bipyridyl)palladium(II) nitrate: synthesis and crystal structure.

The self-assembly of ditopic bis(1H-imidazol-1-yl)benzene ligands (LH) and the complex (2,2'-bipyridyl-κ2N,N')bis(nitrato-κO)palladium(II) affords the supramolecular coordination complex tris[μ-bis(1H-imidazol-1-yl)benzene-κ2N3:N3']-triangulo-tris[(2,2'-bipyridyl-κ2N,N')palladium(II)] hexakis(hexafluoridophosphate) acetonitrile heptasolvate, [Pd3(C10H8N2)3(C12H10N4)3](PF6)6·7CH3CN, 2. The structure of 2 was characterized in acetonitrile-d3 by 1H/13C NMR spectroscopy and a DOSY experiment. The trimeric nature of supramolecular coordination complex 2 in solution was ascertained by cold spray ionization mass spectrometry (CSI-MS) and confirmed in the solid state by X-ray structure analysis. The asymmetric unit of 2 comprises the trimetallic Pd complex, six PF6- counter-ions and seven acetonitrile solvent molecules. Moreover, there is one cavity within the unit cell which could contain diethyl ether solvent molecules, as suggested by the crystallization process. The packing is stabilized by weak inter- and intramolecular C-H...N and C-H...F interactions. Interestingly, the crystal structure displays two distinct conformations for the LH ligand (i.e. syn and anti), with an all-syn-[Pd] coordination mode. This result is in contrast to the solution behaviour, where multiple structures with syn/anti-LH and syn/anti-[Pd] are a priori possible and expected to be in rapid equilibrium.

Crystal structure of a dinuclear ruthenium(II) complex with a bent CO22- bridge.

The mol-ecular and crystal structures of a CO22--bridged dinuclear ruthenium complex is reported, namely, μ-carbonito-κ2C:O-bis-[bis(2,2'-bi-pyridine-κ2N,N')carbon-ylruthenium(II)] bis-(hexa-fluorido-phosphate)-aceto-nitrile-diethyl ether (1/1/0.5), [Ru2(CO)2(C10H8N2)4(μ:κ2-C:O-CO2)](PF6)2·CH3CN·0.5C4H10O. The complex cation in the title compound consists of two {Ru(CO)(bpy)2}2+ units (bpy = 2,2'-bi-pyridine) singly bridged by a μ:κ2-C:O carbonite anion, resulting in an unsymmetrical dinuclear structure. Some of the inter-atomic C⋯O distances involving the carbonyl ligands are shorter than the sum of the van der Waals radii. There are intra-molecular C-H⋯O and aromatic π-π contacts in the cationic complex. In the crystal, the cations are linked by pairs of C-H⋯F hydrogen bonds in addition to weak C-H⋯F inter-actions between the solvent mol-ecules and PF6- counter-anions. The equatorial F atoms of one of the PF6- anions are disordered over two sets of sites with an occupancy ratio of 0.908 (7):0.092 (7) while the central O atom of the diethyl ether solvent mol-ecule is disordered over an inversion centre.

Cationic allylnickel(II) complexes bearing labile N,S-donor ligands: Synthesis, characterization and crystal structure

The thienylimine ligands2,6-dimethyl-N-(thiophen-2-ylmethylene)aniline (L1), 2,6-diisoprop yl-N-(thiophen-2-ylmethylene)aniline (L2) and 4-methyl-N-(thiophen-2-ylmethylene)aniline (L3) were obtained by condensation reactions of 2-formyl thiophene with the corresponding anilines.The reactions of bis(allyl)di-μ-bromodinickel with one or two equivalents of the ligands L1, L2 and L3, in the presence of the thallium hexafluorophosphate TlPF6, in dichloromethane, always afforded the corresponding complexes [Ni(η3-allyl)L2][PF6] (L = L1 (1), L2 (2) or L3(3), containing two monodentate thienylimine ligands coordinated to Ni exclusively through the imine nitrogen atoms when the recrystallization was carried out in a non-coordinating solvent system such as dichloromethane/n-hexane. When complex 2 was recrystallized in dichloromethane/diethyl ether, one of the labile thienylimine ligands was substituted by a weekly coordinating diethyl ether solvent molecule giving rise to complex [Ni(η3-allyl)(L2)(O(C2H5)2)][PF6] (2′). All new complexes 1 [Ni(η3-allyl)(2,6-dimethyl-N-(thiophen-2-ylmethylene)aniline)2][PF6], 2 [Ni(η3-allyl)(2,6-diisopropyl-N-(thiophen-2-ylmethylene)aniline)2][PF6], 3 [Ni(η3-allyl)(4-methyl-N-(thiophen-2-ylmethylene)aniline)2][PF6], and 2’ [Ni(η3-allyl)(2,6-diisopropyl-N-(thiophen-2-ylmethylene)aniline)(O(C2H5)2)][PF6] have been characterized by 1H, 13C,19F,31P NMR and FT-IR spectroscopies and by elemental analysis. The molecular structures in the solid state of complexes 2 and 2′ were determined by X-ray diffraction.

Tris[2,2,6,6-tetra-methyl-8-(tri-methyl-sil-yl)benzo[1,2-d;4,5-d']bis-(1,3-di-thiol)-4-yl]methanol diethyl ether monosolvate.

The title compound, a tri-aryl-methanol, C46H64OS12Si31, was synthesized via li-thia-tion of tris-2,2,6,6-tetra-methyl-benzo[1,2-d;4,5-d']bis-[1,3]di-thiol-4-yl-methanol, 2, and electrophilic quenching with tri-methyl-silyl chloride. The current crystal structure reveals information about the reactivity of this compound and compares well with the structure reported for the unsubstituted parent compound 2 [Driesschaert et al. (2012 ▸). Eur. J. Org. Chem.33, 6517-6525]. The title compound 1 forms mol-ecular propellers and crystallizes in P [Formula: see text], featuring an unusually long Si-Car bond of 1.910 (3) Å. Moreover, the geometry at the central quaternary carbon is rather trigonal-pyramidal than tetra-hedral due to vast intra-molecular stress. One tri-methyl-silyl group is disordered over two positions in a 0.504 (4):0.496 (4) ratio and one S atom is disordered over two positions in a 0.509 (7):0.491 (7) ratio. The contribution of disordered diethyl ether solvent mol-ecule(s) was removed using the PLATON SQUEEZE (Spek, 2015 ▸) solvent masking procedure. These solvent mol-ecules are not considered in the given chemical formula and other crystal data.

New solvates of the drug naltrexone: protonation, conformation and interplay of synthons.

Naltrexone [systematic name: (4R,4aS,7aR,12bS)-3-cyclopropylmethyl-4a,9-dihydroxy-2,4,5,6,7a,13-hexahydro-1H-4,12-methanobenzofuro[3,2-e]isoquinolin-7-one] is an important morphine-related drug used for combating alcoholism and opioid dependence. Of the eight crystal forms of naltrexone known thus far, only one exists in the neutral form and it crystallizes as a monohydrate. We have isolated the naltrexone free base as two new solvate forms, i.e. the ethyl acetate 0.33-solvate, C20H23NO4·0.33C4H8O2, (I), and the diethyl ether hemisolvate, C20H23NO4·0.5C4H10O, (II). While just one solvent molecule is present in the asymmetric unit of each solvate, there are three drug molecules (Z' = 3) in ethyl acetate solvate (I) and two (Z' = 2) in diethyl ether solvate (II). In (I), one of the three crystallographically independent drug molecules is present with its cyclopropyl group disordered over two sets of positions, as is the whole diethyl ether solvent molecule in (II). In all known forms, including the title forms, the naltrexone molecule exhibits the same conformation of the fused rings. The only conformational variability of naltrexone is in the cyclopropylmethyl group. Two conformations can be found around the bond connecting this group to the N-heterocycle, which is directly related to drug protonation. We have calculated, at the B3LYP/6-31G** level of theory, the minimum energy conformations of protonated and neutral naltrexone molecules for a chosen torsion angle about this bond. The lowest energy conformers depend on the protonation state and are in agreement with those found in the solid state. Within the cyclopropylmethyl group, the bond joining the methylene C atom to the cyclopropyl fragment also evidences conformational variability. In the literature, there are two well defined conformations around this bond. A third cyclopropyl conformation around this second bond is observed in the title solvates. Concerning the supramolecular features of the previously reported crystal structures, only one classical hydrogen bond between naltrexone molecules and one C(8) homosynthon is known, pointing to the robustness of this synthon and the difficulty in disrupting it. New R22(7) and C22(10) homosynthons are found in both (I) and (II), suggesting that their occurrence derives from crystallization of the neutral drug from nonpolar solvents.

Di-μ-chlorido-bis({4-[bis(trimethylsilyl)amino]-6-chloro-2,2,8,8-tetramethyl-5,7-bis(trimethylsilyl)-3,5,7-triaza-4,6-diphospha-2,8-disilanon-3-en-4-ido-κ2P,P′}palladium(II)) diethyl ether disolvate

The title compound, [Pd2(C18H54Cl2N4P2Si6)2Cl2]·2C4H10O, features a dinuclear chloride-bridged palladium complex bearing two equivalents of the novel monoanionic mixed valent (λ3-P)—N—(λ5-P) ligand. A metal catalyzed coupling of two aminoiminophosphines and a shift of one chlorine from the metal to the phosphorus results in the (λ3-P)—N—(λ5-P) ligand. The molecule contains a planar bimetallic Pd2Cl2core with a crystallographic centre of inversion at the mid-point of the Pd...Pd line. The Pd atoms are in a distorted square-planar arrangement, where the P/Pd/P and Cl/Pd/Cl planes are twisted with respect to each other by a dihedral angle of 7.57 (4)°. The P—Pd—P bite angle is 71.380 (18)°. Intramolecular C—H...Cl interactions are observed. In the crystal, the diethyl ether solvent molecule is disordered over two sites, with an occupancy ratio of 0.788 (5):0.212 (5).

Free energies for the coordination of ligands to the magnesium of chlorophyll-a in solvents

The coordination of bases to chlorophyll magnesium modifies spectroscopic properties in solution as well as in situ in reaction centres. We evaluate the free energies of complexation of one or two pyridine, 1-propanol, diethyl ether or water solvent molecules at 298 and 150 K to rationalise observed phenomena. Various a priori dispersion-corrected density functional theory calculations are performed as well as second-order Møller–Plesset calculations, focusing on the effects of dispersion modifying the intermolecular interactions, of dispersion modifying solvation energies, of entropy, and of basis-set superposition error. A process of particular interest is magnesium complexation in ether at low temperature that is often exploited to assign the Q-band visible absorption spectrum of chlorophyll. Recently, we demonstrated that trace water interferes with this process, but the nature of the resulting complex could not be uniquely determined; here, it is identified as ether.Chlorophyll-a.H2O, consistent with interpretations based on our authoritative 2013 assignment.

Crystal structures of trans-di-chlorido-tetra-kis-[1-(2,6-diiso-propyl-phen-yl)-1H-imidazole-κN (3)]iron(II), trans-di-bromido-tetra-kis-[1-(2,6-diiso-propyl-phen-yl)-1H-imidazole-κN (3)]iron(II) and trans-di-bromido-tetra-kis-[1-(2,6-diiso-propyl-phen-yl)-1H-imidazole-κN (3)]iron(II) diethyl ether disolvate.

The title compounds, [FeCl2(C15H20N2)4], (I), [FeBr2(C15H20N2)4], (II), and [FeBr2(C15H20N2)4]·2C4H10O, (IIb), respectively, all have triclinic symmetry, with (I) and (II) being isotypic. The Fe(II) atoms in each of the structures are located on an inversion center. They have octa-hedral FeX 2N4 (X = Cl and Br, respectively) coordination spheres with the Fe(II) atom coordinated by two halide ions in a trans arrangement and by the tertiary N atom of four aryl-imidazole ligands [1-(2,6-diiso-propyl-phen-yl)-1H-imidazole] in the equatorial plane. In the two independent ligands, the benzene and imidazole rings are almost normal to one another, with dihedral angles of 88.19 (15) and 79.26 (14)° in (I), 87.0 (3) and 79.2 (3)° in (II), and 84.71 (11) and 80.58 (13)° in (IIb). The imidazole rings of the two independent ligand mol-ecules are inclined to one another by 70.04 (15), 69.3 (3) and 61.55 (12)° in (I), (II) and (IIb), respectively, while the benzene rings are inclined to one another by 82.83 (13), 83.0 (2) and 88.16 (12)°, respectively. The various dihedral angles involving (IIb) differ slightly from those in (I) and (II), probably due to the close proximity of the diethyl ether solvent mol-ecule. There are a number of C-H⋯halide hydrogen bonds in each mol-ecule involving the CH groups of the imidazole units. In the structures of compounds (I) and (II), mol-ecules are linked via pairs of C-H⋯halogen hydrogen bonds, forming chains along the a axis that enclose R 2 (2)(12) ring motifs. The chains are linked by C-H⋯π inter-actions, forming sheets parallel to (001). In the structure of compound (IIb), mol-ecules are linked via pairs of C-H⋯halogen hydrogen bonds, forming chains along the b axis, and the diethyl ether solvent mol-ecules are attached to the chains via C-H⋯O hydrogen bonds. The chains are linked by C-H⋯π inter-actions, forming sheets parallel to (001). In (I) and (II), the methyl groups of an isopropyl group are disordered over two positions [occupancy ratio = 0.727 (13):0.273 (13) and 0.5:0.5, respectively]. In (IIb), one of the ethyl groups of the diethyl ether solvent mol-ecule is disordered over two positions (occupancy ratio = 0.5:0.5).

μ-Butane-1,4-diylbis(di-phenyl-phos-phane)-κ(2) P:P']bis-{[butane-1,4-diylbis(di-phenyl-phosphane)-κ(2) P,P']copper(I)} bis-(hexa-fluorido-phosphate) diethyl ether disolvate.

In the centrosymmetric dinuclear copper(I) complex cation of the title compound, [Cu2(C28H28P2)3](PF6)2·2C4H10O, the CuI atom is bonded to three P atoms of two butane-1,4-diylbis(di­phenyl­phosphane) (dppb) ligands with a triangular coordination geometry. One of these P atoms belongs to a bridging dppb ligand [Cu—P = 2.2381 (5) Å] and two belong to a chelating dppb ligand [Cu—P = 2.2450 (6) and 2.2628 (5) Å]. The bridging dppb ligand lies on an inversion centre. In the crystal, the cation and the PF6 − anion are linked by C—H⋯F inter­actions, forming a tape along [110]. The cation and the diethyl ether solvent mol­ecule are also linked by a C—H⋯O inter­action.

Bis(μ-2-hydroxymethyl-2-methylpropane-1,3-diolato)bis[dichloridotitanium(IV)] diethyl ether disolvate

The title complex, [Ti2Cl4{CH3C(CH2O)2(CH2OH)}2], lies across a centre of symmetry with a diethyl ether solvent mol­ecule hydrogen bonded to the –CH2OH groups on either side of it. The TiIV atom is coordinated in a distorted octa­hedral geometry by a tripodal ligand and two terminal chloride atoms. There are three coordination modes for the tripodal ligand distinguishable on the basis of their very different Ti—O bond lengths. For the terminal alkoxo ligand, the Ti—O distance is 1.760 (1) Å, the asymmetric bridge system has Ti—O bond lengths of 1.911 (1) and 2.048 (1) Å. The Ti—O bond length for the alcohol O atom is the longest at 2.148 (1) Å.

Carbonyl{3,3′-di-tert-butyl-5,5′-dimethoxy-2,2′-bis[(4,4,5,5-tetramethyl-1,3,2-dioxaphospholan-2-yl)oxy]biphenyl-κ2P,P′}hydrido(triphenylphosphane-κP)rhodium(I) diethyl ether trisolvate

In the title compound, [RhH(C74H68O8P2)(C18H15P)(CO)]·3C4H10O, the CHP3 coordination set at the RhI ion is arranged in a distorted trigonal–bipyramidal geometry with the P atoms adopting equatorial coordination sites and the C atom of the carbonyl ligand as well as the H atom adopting the axial sites. The asymmetric unit contains two very similar mol­ecules of the rhodium complex, two half-occupied diethyl ether mol­ecules and further diethyl ether solvent mol­ecules which could not be modelled successfully. Therefore contributions of the latter were removed from the diffraction data using the SQUEEZE procedure in PLATON [Spek (2009 ▶). Acta Cryst. D65, 148–155].

Di-μ-acetato-bis(dimethylformamide)pentakis(μ-N,2-dioxidobenzene-1-carboximidato)tetrakis(1-ethylimidazole)pentamanganese(III)manganese(II)–diethyl ether–dimethylforamide–methanol–water (1/1/1/1/0.12)

The title compound [Mn6(C7H4NO3)5(CH3CO2)2(C5H8N2)4(C3H7NO)2]·(C2H5)2O·C3H7NO·CH3OH·0.12H2O, abbreviated as MnII(OAc)2[15-MCMnIII(N)shi-5](EtIm)4(DMF)2·diethyl ether·DMF·MeOH·0.12H2O (where −OAc is acetate, MC is metallacrown, shi3− is salicylhydroximate, EtIM is n-ethylimidazole, DMF is N,N-dimethylformamide, and MeOH is methanol) contains five MnIII ions as members of the metallacrown ring and an MnII ion bound in the central cavity. The central MnII ion is seven-coordinate with a distorted face-capped trigonal–prismatic geometry. The five MnIII ions of the metallacrown ring are six-coordinate with distorted octa­hedral geometries. The configuration of the MnIII ions about the metallacrown ring follow a ΔΛΔPP pattern, with P representing planar. The four 1-ethyl­imidazole ligands are bound to four different MnIII ions. A diethyl ether solvent mol­ecule was found to be disordered over two mutually exclusive sites with an occupancy ratio of 0.568 (7):0.432 (7). A methanol solvent mol­ecule was found to be disordered over two mutually exclusive sites by being hydrogen bonded either to a dimethyl­formamide solvent mol­ecule (major occupancy component) or to an O atom of the main mol­ecule (minor occupancy component). The occupancy ratio refined to 0.678 (11):0.322 (11). Associated with the minor component is a partially occupied water mol­ecule [total occupancy 0.124 (15)].

Poly[[bis(μ-4,4′-bipyridyl-κ2N:N′)bis(thiocyanato-κN)manganese(II)] diethyl ether disolvate

In the title compound, {[Mn(NCS)2(C10H8N2)2]·2C4H10O}n, the MnII ion is coordinated by four N-bonded 4,4′-bipyridine (bipy) ligands and two N-bonded thio­cyanate anions in a distorted octa­hedral coordination geometry. The asymmetric unit consists of one MnII ion and two bipy ligands each located on a twofold rotation axis, as well as one thio­cyanate anion and one diethyl ether mol­ecule in general positions. In the crystal structure, the metal centers with terminally bonded thicyanate anions are bridged by the bipy ligands into layers parallel to (001). The diethyl ether solvent mol­ecules occupy the voids of the structure.

Coordination polymers of cobalt(II): [Co(4,4′-bpy)2(O2CCF3)2]n and [Co(4,4′-bpy)(O2CCH3)2(H2O)2

Two novel coordination polymers of cobalt(II) have been synthesized and characterized structurally. The first compound, [Co(4,4′-bpy)2(O2CCF3)2] (1), was obtained from the reaction of Co(O2CCF3)2 with 4,4′-bipyridine. Compound 1 has a covalently linked, two-dimensional, fishing-net-like structure. The fishing nets of 1 stack in the lattice, allowing the formation of extended channels that host diethyl ether solvent molecules in the solid state. The second compound, [Co(4,4′-bpy)(O2CCH3)2(H2O)2] (2), was obtained from the reaction of Co(CH3CO2)2·4H2O with 4,4′-bipyridine. Compound 2 has a covalently linked one-dimensional chain structure. In the crystal lattice of 2 the one-dimensional chains form an interpenetrating, three-dimensional structure via interchain hydrogen bonds between acetate and H2O ligands. There are channels parallel to the b axis in the lattice of 2 that appear to host small guest molecules such as methanol and H2O.