Modeling Disorder in the Crystal Structure of the α Polymorph of Alq<Subscript>3</Subscript>

Abstract  

Alq₃, tris(quinolin-8-olato)aluminum(III) is used in the electron transport and/or electron-injecting layer in multilayer organic light-emitting diode device structures. In recent years, five crystalline phases (α, β, γ, δ, and ε) of Alq₃ have been identified. A structure of the α form, containing the meridional isomer, has been reported in literature based on powder XRD data. Single crystals of α Alq₃ have been found to have essentially the same unit cell parameters [triclinic, space group P [`1]P \bar {1}, a = 6.2455(10) ?, b = 12.8710(18) ?, c = 14.739(3) ?, α = 69.890(6)°, β = 89.464(5)°, and γ = 82.520(13)°] as reported previously from powder XRD: triclinic, space group P [`1]P \bar {1}, a = 6.2586(8) ?, b = 12.914(2) ?, c = 14.743(2) ?, α = 109.66(1)°, β = 89.66(1)°, and γ = 97.68(1)°. The single-crystal XRD structure for α Alq₃, however, appeared to be present mostly as the facial isomer, with a high degree of disorder. Although the structure obtained by single-crystal XRD appears to be predominantly or entirely facial, various spectroscopy results (particularly NMR) are more consistent with a meridional composition. To resolve the α Alq₃ isomerism contradiction, we have reconsidered the structural conclusions that were drawn from the single crystal XRD. Based on modeling results, the hypothesis is that α Alq₃ could be a disordered analog of ε Alq_3, with meridional conformation.     

Synthesis and Crystal Structure of 3-Quinuclidinyl α-(Cyclopentyl-1-ene)-α-hydroxy-α-phenylacetate

Abstract The title compound 3-quinuclidinyl α-(cyclopentyl-1-ene)-α-hydroxy-α-phenylacetate was obtained by the reaction of methyl α-(cyclopentyl-1-ene)-α-hydroxy-α-phenylacetate with 3-quinuclidinol in n-heptane. Its structure was characterized by ¹H, ¹³C NMR, MS and X-ray single-crystal diffraction techniques: C₂₀H₂₅NO₃, M _r = 327.41, orthorhombic, space group P2₁2₁2₁ with a = 8.547(2), b = 11.428(4), c = 18.288(5) ?, V = 1786.3(9) ?³, Z = 4. The title compound comprises a tertiary α-hydroxy acid and a bicyclo[2.2.2]octan moiety. The crystal structure shows the presence of the intermolecular O(1)–H(1)···N(1) hydrogen bonds. Index Abstract The title compound, 3-quinuclidinyl α-(cyclopentyl-1-ene)-α-hydroxy-α-phenylacetate was obtained by the reaction of methyl α-(cyclopentyl-1-ene)-α-hydroxy-α-phenylacetate with 3-quinuclidinol in n-heptane and its crystal structure determined. The title compound comprises a tertiary α-hydroxy acid and a bicyclo[2.2.2]octan moiety. The crystal structure shows the presence of the intermolecular O(1)–H(1)···N(1) hydrogen bonds.      

Structure of phosphonium rhenates(VII)

Four phosphonium rhenates(VII) were prepared and crystallized: (A) 1,2-bis (triphenylphosphonium)ethane rhenate(VII) (Pī, a=8.298(2), b=10.638(3), c= 11.242(3) ?, α=64.96(2), β=80.49(2), γ=88.17(2)°), (B) methyltriphenylphosphonium rhenate(VII) (Pca2₁, a=15.096(3), b=12.627(3), c=19.353(3) ?), (C) benzyltriphenylphosphonium rhenate(VII) (Pī, a=9.648(2), b=11.689(2), c=20.806(3) ?, α=88.44(2), β=84.63(2), γ=77.33(3)°), and (D) orthorhombic form of (iodomethyl)triphenylphosphonium rhenate(VII) (Pca2₁, a=14.952(3), b=13.120(3), c=20.603(4) ?). Each crystal structure consists of separate phosphonium cations and rhenate(VII) anions. In A centrosymmetric 1,2-bis(triphenylphosphonium)ethane cations form layers perpendicular to [011]. In B the cations are set in chains along [100] forming layers perpendicular to [001]. In C two symmetrically-independent cations form double columns along [100] and these columns are arranged in puckered layers perpendicular to [001]. D is almost isomorphous to B. The crystal structures are stabilised by weak C–H⋯O hydrogen bonds as well as phenyl rings interactions. In all crystal structures supramolecular motifs of phenyl rings embraces could be distinguished.     

Hydrogen bonding patterns of 2-aminopyridinium nicotinic acetate

The crystal structure of 2-aminopyridinium nicotinic acetate (C₁₁H₁₁N₃O₂) has been determined from X-ray diffraction data using MO Kα radiation. The crystals are monoclinic, P2₁/n, with a=8.787(9) Å, b=12.176(2) Å, c=10.866(2) Å, β=110.11(1)°, and z=4. There is an intermolecular hydrogen bonding between the amino group of the 2-aminopyridine and the oxygen atoms of the nicotinic acetate. Both the six-membered rings are planar. The cations and anions are linked together in chains along the [001] direction by N–HO hydrogen bonds.     

A 2D Network in Co-Crystal (1:1) Based on <Emphasis Type="Italic">trans</Emphasis>-[PtBr<Subscript>2</Subscript>(Acetoxime)<Subscript>2</Subscript>] and 18-Crown-6

Abstract  

A 1:1 co-crystal of trans-[PtBr₂(acetoxime)₂] and 18-crown-6 has been obtained by a slow-evaporation of the equimolar mixture of trans-[PtBr₂(acetoxime)₂] and the crown ether. The compound crystallizes in the triclinic space group P [`1] P\,\bar{1} , with unit cell parameters a = 7.4765(2) Å, b = 9.5044(2) Å, c = 10.1591(3) Å, α = 83.687(1)°, β = 70.847(1)°, γ = 79.773(1)°, Z = 1. trans-[PtBr₂(acetoxime)₂] is assembled with 18-crown-6 into a 2D network structure by interactions between the oxygen atoms of 18-crown-6 and the hydroxylic and methyl hydrogen atoms of the oxime ligands.     

Self-Assembly of a New 1D Coordination Polymer Built of [Nb<Subscript>6</Subscript>Cl<Subscript>12</Subscript>(CN)<Subscript>6</Subscript>]<Superscript>4−</Superscript> and Mn(III) Complexes

Abstract  

A new 1D coordination polymer [Me₄N]₃{[Mn(L)][Nb₆Cl₁₂(CN)₆]}·3MeCN·H₂O (1) (L = acacen ²⁻ = N,N′-bis(acetylacetone)-1,2-ethylenediimine) was synthesized from reaction between [Me₄N]₄[Nb₆Cl₁₂(CN)₆] and [Mn(L)]Cl in acetonitrile. The crystal structure of 1 was determined from single-crystal X-ray diffraction analysis. Compound 1 crystallizes in the tetragonal system, space group I4₁/a (No. 88), a = 30.585(4), c = 27.348(6) ?, V = 25582(7) ?³, Z = 16. Its 1D framework consists of chains formed of metal clusters and Mn(L) complexes linked to each other by Nb–C≡N–Mn–N≡C–Nb linkages. The chains extend along the a and b crystallographic axes and are related to each other by 4₁ screw axis. The chains are held together by [Me₄N]⁺ cations and solvent molecules located in channels running between the chains. 1 and the previously reported 1D coordination polymer [Me₄N]₃{[Mn(5-MeO-salen)][Nb₆Cl₁₂(CN)₆]} (3) differ from each other in terms of their synthesis and their structural characteristics.     

Crystal of Tetrakis(1-ethyl-1H-imidazole)diisothiocyanatocopper(II) bis(1-ethyl-1H-imidazole)diisothiocyanatocopper(II)

Abstract  A new complex [Cu(NCS)₄ (N-Eim)₄] [Cu(NCS)₂ (N-Eim)₂] (where N-Eim = N-ethylimidazole) has been synthesized and structurally characterized by single-crystal X-ray diffraction. The compound crystallizes in the Triclinic space group P−1 with the parameters: a = 8.7707(18) ?, b = 10.712(2) ?, c = 13.511(3) ?, α = 104.73(3)°, β = 104.84(3)°, γ = 102.52(3)°, V = 1131.54(3) ?³, with Z = 1 formula units. In the structure, the copper atoms all assume an elongated octahedral geometry with two distinct coordination environments; one is coordinated by four N-ethyl-imidazole ligands and two axial SCN groups, and another by two SCN groups and two N-ethyl-imidazole ligands. The two units form one infinite 1D zigzag chain along the [1 0 1] plane by two thiocyanate ligands from the [Cu(NCS)₄ (N-Eim)₄] units. Index Abstract  The title compound, tetrakis(1-ethyl-1H-imidazole)diisothio cyanatocopper(II) bis(1-ethyl-1H-imidazole)diisothiocyanatocopper(II) has been synthesized and structurally characterized by single-crystal X-ray diffraction. In the structure, the copper atoms all assume an elongated octahedral geometry with two distinct coordination environments. The two units form one infinite 1D zigzag chain along the [1 0 1] plane by two thiocyanate ligands from the [Cu(NCS)₄ (N-Eim) 4] units.      

One-Dimensional Polymers Constructed with Paddle-Wheel Dinuclear Copper(II) Bridged by 4,4′-Bipyridine

Abstract  

The coordination compound {[Cu(NAP)₂](4,4′-bpy)_1/2}·DMF (1) was prepared by the reaction of α-naphthoic acid, 4,4′-bipyridine and Copper(II) acetate hydrate in basic solution, and was fully characterized by X-ray diffraction, element analysis, FTIR and TG analysis. Crystals of compound 1 belongs to the monoclinic crystal system, space group C2/c; a = 17.460(4) ?, b = 13.928(3) ?, c = 21.240(4) ?, β = 93.83(3), V = 5153.7 ?³, Z = 8. The structure analyses of 1 show a one-dimensional chain structure where the binuclear structural units [Cu₂(NAP)₄] are bridged by 4,4′-bipyridine molecules. Furthermore, the 1D chains are assembled to form 2D supramolecular sheet by intermolecular π···π stacking interactions between naphthalene rings.     

Synthesis, Crystal Structure of a New Co(II) Complex with Pyrazine-2,3,5,6-tetracarboxylic Acid

Abstract A new complex [Co(H₂pztc)(bpy)H₂O] (H₄pztc = pyrazine-2,3,5,6-tetracarboxylic acid, bpy = 2,2′-bipyridine) has been synthesized by hydrothermal reactions of Co(NO₃)₂ · 6H₂O with H₄pztc and bpy and characterized by IR and X-ray diffraction single crystal structure analysis. It belongs to monoclinic system, P2₁/c space group with a = 13.454(2) ?, b = 12.939(2) ?, c = 11.4993(19) ?, α = 90°, β = 111.640(3)°, γ = 90°. This complex is assembled into 3D supramolecular architecture by hydrogen bonds (O–H···O, C–H···O). Index Abstract A new complex of cobalt(II) with pyrazine-2,3,5,6-tetracarboxylic acid and 2,2′-bipyridine is assembled by intermolecular hydrogen bonds forming 2D layer and 3D supramolecular network.      

3D-graphite structure

The structure of clusters of some new carbon 3D-graphite phases have been calculated using the molecular-mechanics methods. It is established that 3D-graphite polytypes α_{1, 1}, α_{1, 3}, α_{1, 5}, α_{2, 1}, α_{2, 3}, α_{3, 1}, β_{1, 2}, β_{1, 4}, β_{1, 6}, β_{2, 1}, and β_{3, 2} consist of sp ²-hybridized atoms, have hexagonal unit cells, and differ in regards to the structure of layers and order of their alternation. A possible way to experimentally synthesize new carbon phases is proposed: the polymerization and carbonization of hydrocarbon molecules.     

Synthesis and Crystal Structure of [1,2,4]-Triazolo-annulated 3-Aza-A-homocholestane Derivative: A Novel Pentaheterocyclic Ring System

Abstract  

A novel pentaheterocyclic ring system derived from (5α)-cholestan-3-one, i.e. [1R-[1α(R*),3aβ,3bα,5aβ,12aα,12bβ,14aα]]-1-(1,5-dimethylhexyl)-1,2,3,3a,3b,4,5,11,12,12a,12b,13,14,14a-tetradecahydro-8,12a,14a-trimethyl-9-(2,4,6-trichlorophenyl)-cyclopenta[5,6]naphtho[2,1-d][1,2,4]triazolo[1,5-a]azepinium hexachloroantimonate (6) has been synthesized via the reverse-electron-demand 1,3-dipolar cycloaddition of the 1-aza-2-azoniaallene cation 4 to the triple bond of acetonitrile followed by ring enlargement. The structure of 6 was determined by NMR, IR and high-resolution mass spectra, and unequivocally confirmed by X-ray crystallographic analysis. The title compound crystallizes in monoclinic class under the space group P2-1 with a = 8.163(3) ?, b = 11.214(4) ?, c = 24.191(9) ?, α = 90°, β = 97.740(5)°, and γ = 90°. The five-membered triazole ring is essentially planar and aromatic, while the seven-membered azepine ring is not planar, but adopts a chair-like conformation.     

(20R,22R)-6α,7α-Epoxy-5α,27-dihydroxy-1-oxowitha-2,24-dienolide in Leaves of Withania somnifera: Isolation and its Crystal Structure

Abstract  (20R,22R)-6α,7α-Epoxy-5α,27-dihydroxy-1-oxowitha-2,24-dienolide (27-hydroxy-withanolide B) was isolated from Withania somnifera. The structure of the withanolide was established by spectral analysis and X-ray diffraction studies. The compound crystallizes in the orthorhombic space group P2₁2₁2₁ with unit cell parameters: a = 9.2163(3), b = 11.1828(4), c = 23.6146(9) ?, Z = 4. The crystal structure was refined to R = 0.0495 for 3,284 observed reflections. All the rings of the steroid skeleton are trans connected. Rings A and B exist in a half-chair conformation, ring C a chair, and five membered ring D is intermediate between a half-chair and an envelope. The δ-lactone ring E adopts a distorted sofa conformation. The twist along the length of the steroid nucleus is −6.5°. The characteristic pattern observed in the packing diagram is the appearance of twisted chains of molecules packed together to form layers. Index Abstract  Isolation and crystal structure analysis of (20R,22R)-6α,7α-epoxy-5α,27-dihydroxy-1-oxowitha-2,24-dienolide.      

Hydrogen Bonded 3D Supramolecular Architectures of Two Organic Salts Assembled from 2-Aminoheterocyclic Compounds and Phosphoric Acid

Abstract  

Two phosphate salts (2-aminopyrimidine): (phosphoric acid): H₂O [HL1⁺ (H₂PO₄) ⁻ ]·H₂O (1), and (4-phenylthiazol-2-amine): (phosphoric acid) [HL2⁺·(H₂PO₄)⁻] (2) based on 2-aminoheterocyclic compounds, 2-aminopyrimidine (L1), and 4-phenylthiazol-2-amine (L2) were prepared and structurally characterized by X-ray crystallography. Compound 1 crystallizes in the triclinic, space group P-1, with a = 6.2201(7) Å, b = 8.6139(9) Å, c = 9.4800(10) Å, α = 109.685(2)°, β = 106.3340(10)°, γ = 95.4450(10)°, V = 448.72(8) Å³, Z = 2. For 1, the cations were linked to each other via intermolecular C–H···N hydrogen bonds to form a 1-D chain structure running along the a-axis direction. The anions and the water molecules were connected alternatively along the a-axis direction through O–H···O hydrogen bonds to form a 1-D chain also. The cationic chains and the anionic chains were alternatively connected along the c-axis direction through N–H···O and C–H···O hydrogen bonds to form a 2D corrugated sheet. Adjacent sheets were combined together through π–π interaction to form double sheet. These double sheets were further joined together by O–H···O and N–H···O hydrogen bonds to produce a 3D network structure. Compound 2 crystallizes in the Orthorhombic, space group Pbca, with a = 10.1929(10) Å, b = 8.4406(9) Å, c = 27.589(2) Å, α = 90°, β = 90°, γ = 90°, V = 2373.6(4) Å³, Z = 8. In 2, the phosphates formed 1D chain along the b-axis through two P–O–H···O = P hydrogen bonds. The cations formed 1D zigzag chain along the b-axis direction under the CH–π interaction. The anionic chains were intercalated between two adjacent cationic chains through N–H···O, O–H···O, C–H···O, and O–S contacts. Such stacking repeated along the c-axis direction to form a 3D network structure.     

6α,7α-epoxy-5α,17α,dihydroxy-1-oxo-22R-witha-2,24-dienolide in leaves of Withania somnifera: Isolation and its crystal structure

6α,7α-epoxy-5α,17α,dihydroxy-1-oxo-22R-witha-2,24-dienolide (C₂₈H₃₈O₆) was isolated from Withania somnifera leaves. The structure of the withanolide was established by spectral analysis and X-ray diffraction studies as withanone. The compound crystallizes in the orthorhombic space group P2₁2₁2₁ with unit cell parameters: a = 9.191(10) Å, b = 12.858(6) Å, c = 21.400(16) Å, Z = 4. The crystal structure was solved by direct methods and refined to R = 0.0603 for 1742 observed reflections. There is positional disorder of the H atom in a hydroxy group (O5), resulting in two possible hydrogen-bond linkages. All the rings of the steroid skeleton are trans connected. Ring A exists in a half-chair conformation, ring B is intermediate between a half-chair and a sofa, ring C a distorted chair, and five-membered ring D is intermediate between a half-chair and an envelope. The δ-lactone ring E adopts a sofa conformation. The twist along the length of the steroid nucleus is negligible [C19–C10…C13–C18=1.8°]. Both the hydroxy groups are involved in hydrogen bonding.     

Self-Assembly of C-Methyl Calix[4]resorcinarene with 5,5′-Bipyrimidine

Abstract The X-ray crystal structure of the complex formed between 5,5′-bipyrimidine and C-methylresorcinarene is described. The structure (C₄₁H₄₅N₅O₁₂) is triclinic with a = 12.8610(10), b = 13.0560(10), c = 13.6068(11)?, α = 104.0730(10), β = 104.9260(10), γ = 111.6430(10)° and space group P-1. The structure reveals that the resorcinarene adopts a boat conformation and forms a three-dimensional network through hydrogen bonding to two water molecules and one dipyrimidine ligand. A single nitromethane molecule is included in the superstructure. Graphical Abstract Self-Assembly of C-Methyl Calix[4]resorcinarene with 5,5’-Bipyrimidine Charles L. Barnes(1) and Eric Bosch(2)* The X-ray crystal structure of the complex formed between 5,5′-bipyrimidine and C-methylresorcinarene is reported.      

Crystal Structure of 2, 8, 14, 20-<Emphasis Type="Italic">tert</Emphasis>-Butylpyrogallol[4]arene

Abstract  The aromatic derivative 2, 8, 14, 20-tert-butylpyrogallol[4]arene was synthesized by the acid catalyzed condensation of pivalaldehyde and pyrogallol in refluxing aqueous ethanol. Single crystal X-ray analysis revealed that the molecule crystallizes in the monoclinic crystal system; space group: P2₁/c. Unit cell dimensions: a = 11.1175(7) ?, α = 90°, b = 23.4525(15) ?, β = 101.6720(10)°, c = 21.9595(14) ?, γ = 90°, D_calc = 1.205 Mg/m³ g/m³ for Z = 4. In the solid state, the macrocycle is found to adopt a crown structure that is unique for the rcct conformation. Graphical abstract   Crystal Structure of 2, 8, 14, 20- tert -Butylpyrogallol[4]arene Eric E. Dueno, Allen D. Hunter, Matthias Zeller, Thomas A. Ray, Ralph N. Salvatore, Cesar H. Zambrano Acid catalyzed condensation of pyrogallol and pivalaldehyde in refluxing aqueous ethanol afforded a pyrogallol[4]arene derivative in good yield. Single crystal X-ray diffraction analysis revealed that a new calyx-like structure was formed under the reaction conditions. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.

X-Ray Crystallographic Structure of the Cyclic Di-amino Acid Peptide: <Emphasis Type="Italic">N,N</Emphasis>′-Diacetyl-cyclo(Gly-Gly)

Abstract  

The cyclic di-amino acid peptide N,N′-diacetyl-cyclo(Gly-Gly), C₈H₁₀N₂O₄, crystallizes in the triclinic space group P[`1] P\bar{1} with unit cell parameters a = 9.4855(4) ?, b = 10.0250(3) ?, c = 10.0763(4) ?, α = 73.682(2)°, β = 82.816(2)°, γ = 81.733(2)°, V = 906.40(6) ?<sup>3</sup>, Z = 4 (2 molecules, A and B, per asymmetric unit), D<sub>c</sub> = 1.452 g cm<sup>−3</sup> and linear absorption coefficient 0.118 mm<sup>−1</sup>. The crystal structure determination was carried out with MoKα X-ray data measured at 120(2) K. In the final refinement cycle the data/restraints/parameter ratios were 4124/0/258 and goodness-of-fit on F<sup>2</sup> = 1.0008. Final R indices for [I > 2σ(I)] were R<sub>1</sub> = 0.0501, wR<sub>2</sub> = 0.1007 and R indices (all data) R<sub>1</sub> = 0.0864, wR<sub>2</sub> = 0.11180. The largest electron density difference peak and hole were 0.241 and −0.232 e ?<sup>−3</sup>, respectively. The DKP rings in both molecules A and B have boat conformations with pseudo mm2 (C<sub>2v</sub>) symmetry if the N atoms and CH<sub>2</sub> groups are considered identical. In each case, the prow and stern of the boat are the α-carbons C(3) and C(6). The overall molecular symmetry of molecules A and B is approximately C<sub>2</sub> with the twofold symmetry axis of the DKP boat being maintained through the centre of the DKP ring. Details of the molecular geometry are compared with that of the parent compound cyclo(Gly-Gly) in which the DKP ring is planar with exact symmetry [`1] \bar{1} (C_i).     

Crystal Structure, Absolute Configuration, Conformational Analysis and Molecular Dynamics Study of the Novel Steroidal Tetrazole Derivative: (25R)-3,12a-diaza-A,C-bishomo-5α-spirostano[3,4-d] [12a,12d] bistetrazole [HS-989]

Abstract  

The X-ray crystal structure of the bistetrazole steroid derivative: (25R)-3,12a-diaza-A,C-bishomo-5α-spirostano[3,4-d] [12a,12d] bistetrazole (HS-989) has been determined at room temperature. The crystals are orthorhombic, space group P2₁2₁2₁ with a = 16.855(1) ?, b = 25.048(2) ?, c = 6.402(1) ?, V = 2702.7(5) ?³ Z = 4, Density (calculated) = 1.250 Mg/m³. The tetrazole-modified 7-membered rings A and C have similar modified uniaxial chair conformations, with pseudo-symmetry m through the extra C–N tetrazole bond; the 6-membered rings B and F are symmetrical chairs; of the 5-membered rings, D is in a half-chair and ring E an envelope conformation; tetrazole rings T1 and T2 are both planar and oriented towards the α-face. The spirostan moiety is β-oriented. Overall the modified steroid skeleton is reasonably flat, with a pseudo-torsion angle C(19)–C(10)···C(13)–C(18) of −6.2°. Conformational sampling, using high temperature SYBYL molecular dynamics was used to investigate different arrangements of the steroid skeleton. Predicted low energy conformations were found to compare favourably in some respects with both X-ray crystallographic and NMR observations but with important differences.     

Crystal Structure and Characterization of [Ni(RPOEt)<Subscript>2</Subscript>(C<Subscript>2</Subscript>H<Subscript>5</Subscript>OH)<Subscript>2</Subscript>](ClO<Subscript>4</Subscript>)<Subscript>2</Subscript> [RPOEt = bis{(diphenylphosphinyl)methyl}ethyl phosphinate]

Abstract  

The compound [Ni(RPOEt)₂(C₂H₅OH)₂](ClO₄)₂ (1) [RPOEt = bis{(diphenylphosphinyl)methyl}ethyl phosphinate] has been prepared in the form of single crystals and characterized by elemental and thermal analyses, IR spectroscopy and by a single crystal X-ray diffraction study. The complex crystallizes in the triclinic P[`1] P\bar{1} space group with a = 9.8773(5), b = 13.741(1), c = 14.287(1) ?, α = 64.313(9), β = 70.280(5), γ = 89.973(7)o, V = 1620.5(2) ?³, and Z = 1. The nickel(II) atom in 1, situated at the centre of symmetry, is coordinated by four oxygen atoms from two RPOEt ligands and two oxygen atoms from two ethanol molecules in a slightly distorted octahedral environment. The third phosphoryl-oxygen atom from the phosphinate ligand is hydrogen bonded to the oxygen atom of the ethanol molecule coordinated to nickel(II). The complex [Ni(RPOEt)₂(C₂H₅OH)₂]²⁺ cations are linked by the C–H···O hydrogen bonds into one-dimensional chains and by the composite π···π and C–H···π phenyl interactions into a final three-dimensional structure.