Supraicosahedral polyhedra in carboranes and metallacarboranes: The role of local vertex environments in determining polyhedral topology and the anomaly of 13-vertex closo polyhedra

Metal-free carboranes having 13 vertices are anomalous since their closo polyhedra having the expected 28 skeletal electrons are not the usual deltahedra with exclusively triangular faces but instead polyhedra with one or two trapezoidal faces obtained by removal of one or more edges from the corresponding 13-vertex deltahedron. Removal of such edges converts degree 6 boron vertices in the 13-vertex deltahedron into more favorable degree 5 boron vertices while lowering the degree of nearby carbon vertices. Thus the anomaly of the 13-vertex carborane closo polyhedron can be rationalized by the preference of boron for degree 5 vertices. The 12-vertex tetracarbon carborane (CH₃)₄C₄B₈H₈ with a nido electron count of 28 skeletal electrons but with two quadrilateral faces has a solid state structure derived from a 13-vertex “closo” polyhedron with one quadrilateral face by removal of a degree 4 vertex to give the second quadrilateral face. However, the corresponding tetraethyl derivative (C₂H₅)₄C₄B₈H₈ has a different solid state structure derived from removal of a degree 6 vertex from an unusual 13-vertex deltahedron with three degree 6 vertices to give an open hexagonal face rather than two quadrilateral faces. In contrast to the 13-vertex closo polyhedra, the 14-vertex closo polyhedron is a true deltahedron, namely the D_6d bicapped hexagonal antiprism, which is found in a carborane derivative as well as in several dimetallacarboranes with the metal atoms always at the degree 6 vertices. However, the 15-vertex closo polyhedron, so far found only in the metallaborane 1,2-μ-(CH₂)₃C₂B₁₂H₁₂Ru(η⁶-p-cymene), is a non-deltahedron with one quadrilateral face.     

The Chirality of Icosahedral Fullerenes: a Comparison of the Tripling (leapfrog), Quadrupling (chamfering), and Septupling (capra) Transformations

Fullerene polyhedra of icosahedral symmetry have the midpoints of their 12 pentagonal faces at the vertices of a macroicosahedron and can be characterized by the patterns of their hexagonal faces on the (triangular) macrofaces of this macroicosahedron. The numbers of the vertices in fullerene polyhedra of icosahedral symmetry satisfy the Goldberg equation v=20(h ²+hk+k ²), where h and k are two integers and 0 <h≥ k≥ 0 and define a two-dimensional Goldberg vector G = (h, k). The known tripling (leapfrog), quadrupling (chamfering), and septupling (capra) transformations correspond to the Goldberg vectors (1, 1), (2, 0), and (2, 1), respectively. The tripling and quadrupling transformations applied to the regular dodecahedron generate achiral fullerene polyhedra with the full I _h point group. However, the septupling transformation destroys the reflection operations of the underlying icosahedron to generate chiral fullerene polyhedra having only the I icosahedral rotational point group. Generalization of the quadrupling transformation leads to the fundamental homologous series of achiral fullerene polyhedra having 20 n ² vertices and Goldberg vectors (n, 0). A related homologous series of likewise achiral fullerene polyhedra having 60 n ² vertices and Goldberg vectors (n, n) is obtained by applying the tripling transformation to regular dodecahedral C₂₀ to give truncated icosahedral C₆₀ followed by the generalized operations (as in the case of quadrupling) for obtaining homologous series of fullerenes. Generalization of the septupling (capra) transformation leads to a homologous series of chiral C_20m fullerenes with the I point group and Goldberg vectors G=(h, 1) where m=h ²+h+1.     

Synthesis and crystal structure of new double mercury silver phosphide iodide Hg<Subscript>12</Subscript>Ag<Subscript>41</Subscript>P<Subscript>88</Subscript>I<Subscript>41</Subscript>

New double mercury silver phosphide iodide Hg₁₂Ag₄₁P₈₈I₄₁ (1) was synthesized and its crystal structure was established. Compound 1 crystallizes in the cubic system. The characteristic feature of the crystal structure 1 is the presence of the anionic cage clusters P₁₁ ³⁻, which have been previously found in alkali metal compounds only. The well-ordered P₁₁ ³⁻ clusters form a system of polyhedra, which encapsulate various disordered α-AgI-type fragments. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1882–1886, October, 2007.     

Generation of carbon-cage polyhedra

The problem of the generation of polyhedra with degree-3 vertices, and faces each of which is pentagonal or hexagonal, is addressed in order to characterize carbon in order to characterize clusters of ca. 30 or more atoms. Following Eulerian type arguments such polyhedra are subcategorized in terms of numbers of different types of local structures. An algorithm to generate such polyhedra is developed, and its computer implementation is described. Results for smaller than 80-vertex cages of subcategories anticipated to be more chemically relevant are reported. The singular position of the truncated-icosahedron (buckminsterfullerene) structure is noted.     

Topological aspects of chemically significant polyhedra

This paper considers both static and dynamic properties of chemically significant polyhedra. Static properties of polyhedra consider relationships between the numbers and degrees/sizes of polyhedral vertices, edges, and faces; polyhedral symmetries; and numbers of topologically distinct polyhedra of various types. Dynamic properties of polyhedra involve studies of polyhedral isomerizations from both macroscopic and microscopic points of view. Macroscopic aspects of polyhedral isomerization can be described by graphs called topological representations in which the vertices correspond to different permutational isomers and the edges to single degenerate polyhedral isomerization steps. Such topological representations are presented for isomerizations of polyhedra having five, six, and eight vertices. Microscopic aspects of polyhedral isomerizations arise from consideration of the details of polyhedral topology, such as the topological aspects of diamond-square-diamond processes. In this connection, Gale diagrams are useful for describing isomerizations of five- and six-vertex polyhedra, including the Berry pseudorotation of a trigonal bipyramid through a square pyramid intermediate and the Bailar or Ray and Dutt twists of an octahedron through a trigonal prism intermediate.     

Chemical applications of topology and group theory

This paper characterizesforbidden polyhedra, which are polyhedra with fewer than 9 vertices which cannot be formed using only the 9s,p, andd atomic orbitals. In this connection polyhedra are of particular interest if their symmetry groups are direct product groups of the typeR × C′ _s in whichR is a group containing only proper rotations andC′ _s is eitherC _s orC _i in which the non-identity element is an inversion center or a reflection plane which is called theprimary plane of the groupR ×C′ _s . Using this terminology polyhedra of the following types are shown always to be forbidden polyhedra: (1) Polyhedra having 8 vertices, such direct product symmetry point groups, and either an inversion center or aprimary plane fixing either 0 or 6 vertices; (2) Polyhedra having a 6-fold or higherC _n rotation axis. However, these conditions are not necessary for a polyhedron to be forbidden since in addition to one 7-vertex polyhedron and ten 8-vertex polyhedra satisfying one or both of the above conditions there are two forbiddenC _3v 8-vertex polyhedra which satisfy neither of the above conditions. For part 15 of this series see reference 1.     

The effect of CH<Subscript>3</Subscript>, F and NO<Subscript>2</Subscript> substituents on the individual hydrogen bond energies in the adenine–thymine and guanine–cytosine base pairs

The substituent effects on the geometrical parameters and the individual hydrogen bond (HB) energies of base pairs such as X–adenine–thymine (X–A–T), X–thymine–adenine (X–T–A), X–guanine–cytosine (X–G–C), and X–cytosine–guanine (X–C–G) have been studied by the quantum mechanical calculations at the B3LYP and MP2 levels with the 6–311++G(d,p) basis set. The electron withdrawing (EW) substituents (F and NO₂) increase the total binding energy (ΔE) of X–G–C derivatives and the electron donating (ED) substituent (CH₃) decreases it when they are introduced in the 8 and 9 positions of G. The effects of substituents are reversed when they are located in the 1, 5, and 6 positions of C, with exception of CH₃ in the 1 position and F in the 5 position, which in both cases the ΔE value decreases negligibly small. With minor exceptions (X=8–CH₃, 8–F, and 9–NO₂), both ED and EW substituents increase slightly the ΔE values of X–A–T derivatives. The individual HB energies (∆E _HBs) have been estimated using electron densities that calculated at the hydrogen bond critical points (HBCPs) by the atoms in molecules (AIM) method. Most of changes of individual HBs are in consistent with the ED/EW nature of substituents and the role of atoms entered H-bonding. The remarkable change is observed for NO₂ substituted derivative in each case.     

Ionic mobility,structure, and conductivity of 45ZrF<Subscript>4</Subscript>-35BiF<Subscript>3</Subscript>-20CsF glass according to <Superscript>19</Superscript>F NMR,IR, Raman,and impedance spectroscopy

¹⁹F NMR, IR, Raman and impedance spectroscopy are used to study the ionic mobility, structure, and conductivity of 45ZrF₄-35BiF₃-20CsF bismuth fluorozirconate glass. With the increase in temperature from 150 K to 500 K the fluorine-containing groups pass from the rigid lattice to local movements (reorientations), and then to diffusion. According to the results of IR and Raman spectroscopy, the lattice of this glass consists of ZrF₈ polyhedra linked by their vertices into chains. The glass has high ionic conductivity: σ ≈ 1.8×10⁻⁴ S/cm in a temperature range of 480–485 K.     

Antioxidant activityofaromatic alkaloids from the marine sponges <Emphasis Type="Italic">Aaptos aaptos</Emphasis> and <Emphasis Type="Italic">Hyrtios</Emphasis> SP.

Aaptamine (1) and isoaaptamine (2) were isolated from the marine sponge Aaptos aaptos; 6-bromo-2′-de-N-methylaplysinopsin (3) from the marine sponge Hyrtios sp. Alkaloids 1–3 were tested for the ability to trap 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical, to reduce Folin–Ciocalteau reagent (FCR), and to inhibit oxidation of linoleic acid (LA) induced by peroxide radicals. Compounds 1 (IC₅₀ 18 μM), 2 (IC₅₀ 16 μM), and 3 (IC₅₀ 18 μM) reacted strongly with DPPH, comparable with trolox (IC₅₀ 16 μM) and showed high reducing ability for FCR. The inhibition of LA oxidation by 1–3 was comparable with that of ionol (BHT). It was shown that the antioxidant activity of 1–3 was related to their ability to release both electrons and H atoms.     

Density functional computations of alkynylation of nitrones catalyzed by chiral zinc(II)-complexes

The alkynylation of nitrones catalyzed by chiral zinc(II)-complexes was studied by means of the density functional theory (DFT). All the intermediates and transition states were optimized completely at B3LYP/6-31G(d,p) level. Calculation results confirm that this alkynylation of nitrones was endothermic and the total absorbed energy was about 14 kJ/mol. The formation of the M5 complexes was the rate-determining step and the chirality-limiting step for this alkynylation. The transition states TS3-re involve a H(8)–O(2)–Zn(6)–C(9)–C(14)–N(13)–O(12) 7-membered ring, and thus the transition states TS3-si involve a Zn(6)–C(9)–C(14)–N(13)–O(12) 5-membered ring. The dominant reaction is the attack of nitrones from the re-surface of M4. The reactivity of anti-nitrones was stronger than that of syn-nitrones for zinc-catalyzed alkynylation of nitrones. The dominant reaction channel was cata → TS1b → M1b → M2 → M3b → TS2b → M4b → TS3b1-anti-re → M5b1-anti-re → Pro-R. The dominant products predicted theoretically were of R-chirality, (2R)-N-hydroxy-N-methylpent-3-yn-2-amine. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Optimization of the Extraction Conditions and Simultaneous Quantification by RP-LC of Six Alkaloids in Evodiae Fructus

A reversed phase liquid chromatographic (LC) method coupled with DAD (250 nm) has been developed and validated for simultaneous quantification of six alkaloids, dehydroevodiamine (1), wuzhuyuamide-I (2), 5-hydroxyrutaecarpine (3), 14-formyldihydrorutaecarpine (4), evodiamine (5) and rutaecarpine (6), in 12 batches evodiae fructus [the dried, unripe fruits of Evodia rutaecarpa (Juss.) Benth. or E. rutaecarpa (Juss.) Benth. var. officinalis (Dode) Huang, E. rutaecarpa (Juss.) Benth. var. bodinieri (Dode) Huang] as a traditional Chinese medicine. The method was carried out by a C₁₈ column (250 × 4.6 mm) with a gradient mobile phase of methanol, acetonitrile, and phosphoric acid–triethylamine–buffer solution. The contents of 1–6 in the evodiae fructus could easily be determined within 70 min. The experimental results were satisfactory for the intra-day and inter-day precision and accuracy of the method for simultaneous determination. The linear calibration ranges of 1–6 were 40–1,000, 20–500, 1–100, 10–500, 40–1,000 and 80–1,000 μg mL⁻¹. The recoveries of 1–6 were 97.43–103.73% with RSDs from 0.21 to 1.99%. The limits of detection for 1–6 were 2.0, 2.0, 0.1, 1.0, 5.0 and 5.0 μg mL⁻¹, and the limits of quantification were 6.6, 6.6, 0.3, 3.3, 16.5 and 16.5 μg mL⁻¹. The method was successfully applied to the quantification of six alkaloids in the evodiae fructus.     

The three-center-four-electron (3c-4e) bond nature revisited. An atoms-in-molecules theory (AIM) and ELF study

Theoretical calculations (B3LYP/6–311+ +G**) were performed on a series of formally hypervalent compounds showing linear three-center geometries. The bonding nature was analyzed by the electron density, ρ(r), and electron-localization function (ELF) topologies, including calculations of the AIM charges and NMR chemical shifts (GIAO method). In addition, a quantitative analysis was also performed of the localization and delocalization indexes, obtained from the electron-pair density in conjunction with the definition of an atom in a molecule. Furthermore, the populations and fluctuations in the ELF basins were also evaluated. The compounds studied presented linear (1–5), T-shaped (6–9), and bipyramidal structures (10–15). Our results support the 3c-4e model for the linear (1–5) structures, but reveal for the T-shaped (6–9) structures only a small contribution from this model. In addition, there is no evidence to support the 3c-4e bond scheme for the bipyramidal compounds (10–15). Received: 1 June 2000 / Accepted: 4 October 2000 / Published online: 19 January 2001     

Theoretical study on dithieno[3,2-b:2′,3′-d]phosphole derivatives: high-efficiency blue-emitting materials with ambipolar semiconductor behavior

Phosphole-based systems due to the unique electronic and optical properties have recently been paid much attention as optoelectronic materials. In this work, the relationship among the electronic structure, charge injection, and transport was investigated for five derivatives of dithieno[3,2-b:2′,3′-d]phosphole (systems 1–5). The structures of systems 1–5 in the ground (S₀) and the lowest singlet excited (S₁) states were optimized at the HF/6-31G* and CIS/6-31G* levels of theory, respectively. Based on these structures, electronic spectra were calculated by time-dependent density functional theory. The simulated emission peaks of five phosphole derivatives locating at the blue–green region (448–516 nm), are in good agreement with the experimental data. Compared with tris-(8-quinolinolate) aluminum (III) (Alq₃), normally used as an excellent electron transporter, systems 1–5 show a significant improvement in electron affinity (EA) due to σ*–π* hyperconjugation, which can effectively promote ability of electron injection. The small differences between λ _h and λ _e for systems 1–5 (0.06–0.14 eV) facilitate charge transfer balance, which suggests systems 1–5 can act as potential ambipolar materials. Owing to good rigidity, low-lying LUMO levels, delocalized frontier molecular orbitals, and the small reorganization energies, the five derivatives of dithieno[3,2-b:2′,3′-d]phosphole are expected to be high-efficiency blue materials in single-layer OLEDs.     

Synthesis and photophysical behavior of thia-aza macrocycles with 9-anthracenylmethyl moiety as fluorescent appendage

1,3-Bis(bromomethyl)-2-methoxy-5-methylbenzene, 1,3-bis(bromomethyl)-2,4,6-trimethylbenzene, 1,3- and 1,4-bis(bromomethyl)benzene undergo nucleophilic substitution with methyl mercaptoacetate to provide respective diesters 6–9. These diesters (6–9) on stirring with bis(3-aminopropyl)amine and diethylenetriamine in methanol–toluene (1:1) mixture undergo intermolecular cyclization to give respective thia-aza macrocycles 10–15. The alkylation of macrocycles 10–13 with 9-anthracenylmethyl chloride gave amine N-(anthracenylmethyl) substituted macrocycles 16–19. The extraction profile of macrocycles 10–15 towards alkali (Li⁺, Na⁺, K⁺), alkaline earth (Mg²⁺, Ca²⁺, Sr²⁺, Ba²⁺), Ag⁺, Tl⁺ and Pb²⁺ picrates shows preferential extraction of Ag⁺ with these macrocycles. The macrocycles 16–19 show fluorescence spectrum typical of anthracene moiety and depending on their structures exhibit 0–80 times increase in fluorescence on addition of transition metal ions. Fluorescent receptors 16, 17, and 19 are capable of functioning as a very efficient multi input OR logic gate.

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Graphical abstract 1,3- and 1,4-Bis(bromomethyl)benzene and its substituted derivatives undergo nucleophilic substitution with methyl mercaptoacetate to provide respective diesters 6–8. These diesters (6–8) on stirring with bis(3-aminopropyl)amine in methanol–toluene (1:1) mixture undergo intermolecular cyclization to give respective thia-aza macrocycles 10–12. The alkylation of macrocycles 10–12 with 9-anthracenylmethyl chloride gave amine N-(anthracenylmethyl) substituted macrocycles 16–18. The macrocycles 16–18 exhibit 0–80 times increase in fluorescence on addition of transition metal ions.

     

Syntheses,spectroscopic and crystallographic characterizations of 4-nitrobenzyloxy derivatives and benzofurans from <Emphasis Type="Italic">ortho</Emphasis>-substituted benzaldehydes and 4-nitrobenzyl bromide

A series of benzyloxybenzaldehyde derivatives (1–3) were prepared by the reactions of 4-nitrobenzyl bromide with 4-hydroxy-3-methoxybenzaldehyde (vanillin), 2-hydroxy-3-methoxybenzaldehyde (o-vanillin) and 2-hydroxy-4-methoxybenzaldehyde. When the reaction time is quite long, benzofuran derivatives (4 and 5) were obtained by the reactions of ortho-hydroxyaldehydes with the 4-nitrobenzyl bromide. Condensation reactions among the three benzyloxybenzaldehyde derivatives (1–3) with 2-aminomethylfuran (furfurylamine) yielded the new imine compounds (6–8). The structures of these aldehydes (1–3), benzofuran derivatives (4 and 5) and imine compounds (6–8) were confirmed on the basis of elemental analyses, IR, ¹H NMR and ¹³C NMR and mass spectroscopy. The solid-state structures of compounds 4–6 were determined by single-crystal X-ray crystallography.     

Theoretical study of structure and properties of hexuronic acid and <Emphasis Type="SmallCaps">d</Emphasis>-glucosamine structural units of glycosaminoglycans

The Becke3LYP functional of DFT theory was used to investigate molecular structure and sodium affinity of the systems CH₃CO₂Na (1), CH₃–O–SO₃Na (2), CH₃–NH–SO₃Na (3), saccharide_1Na₂ (4), saccharide_2Na (5), saccharide_3Na₃ (6), saccharide_4Na₂ (7), and saccharide_5Na₂ (8), respectively, which are models of N- and O-sulfate glycosaminoglycans. Interaction enthalpies, entropies and Gibbs energies of the sodium-coordinated systems in the gas phase were determined with the B3LYP/6-311+G(d,p) and B3LYP/6-31+G(d) methods. The computed Gibbs energies, ΔG ^o , of model systems 1–3 are negative and span a rather broad energy interval (from −500 to −1,500 kJ mol⁻¹). Gibbs interaction energies for sodium acetate, sodium sulfate and sodium sulfamate functions of the five saccharides, systems 4–8 are always lower than those values found for the model compounds 1–3. The ionization of sodium salts of saccharides studied in gas phase is in most cases connected with considerable conformational rearrangement of the ionic species. This rearrangement causes an additional energetic stabilization of anionic species and is connected with the substantial release of entropy.     

Steric distortion of planar NiP<Subscript>2</Subscript>N<Subscript>2</Subscript> chromophores: a spectral,cyclic voltammetric and single crystal X-ray structural study

The complexes trans-[Ni(4-MP)₂(NCS)₂]·MeCN (1) and trans-[Ni(3-MP)₂(NCS)₂] (2) (4-MP = tri(4-methylphenyl)phosphine, 3-MP = tri(3-methylphenyl)phosphine) were prepared and characterized by IR, UV–visible, NMR spectra, CV, TGA and single crystal X-ray crystallography. Both the complexes have planar geometry and are diamagnetic. The Ni–P distances in both complexes are relatively short as a result of strong back donation from nickel to phosphorus. The phenyl rings in the 3-MP analogue (2) show increased pitching with reference to the plane formed by the ipso carbons due to increased steric effects. For complex (2), the N–Ni–N and P–Ni–P angles are significantly lower than the almost linear N–Ni–N and N–Ni–P angles observed for both complex (1) and trans-[Ni(PPh₃)₂(NCS)₂]. This observation indicates that the 3-methylphosphine ligand forces complex (2) to distort towards a tetrahedral geometry. IR spectra of both complexes show strong bands around 2,090 cm⁻¹ due to N-coordinated thiocyanate, while the electronic spectra contain d–d transitions around 452 nm. Cyclic voltammograms show that the irreversible one-electron reduction potentials increase in the following order: trans- [Ni(PPh₃)₂(NCS)₂] < trans- [Ni(3-MP)₂(NCS)₂] < trans-[Ni(4-MP)₂(NCS)₂], revealing the electron releasing effect of the methyl groups. The planar complexes exhibit interallogony in coordinating solvents.     

Complete basis set,hybrid-DFT study,and NBO interpretations of the conformational behavior of 1,2-dihaloethanes

The conformational behavior of 1,2-difluoroethane (1), 1,2-dichloroethane (2), 1,2-dibromoethane (3), and 1,2-diiodoethane (4) have been analyzed by means of complete basis set CBS-QB3, hybrid-density functional theory (B3LYP/Def2-TZVPP) based methods and natural bond orbital (NBO) interpretation. Both methods showed the expected greater stability of the gauche conformation of compound 1 compared to its anti conformation. Contrary to compound 1, the anti conformations of compounds 2–4 are more stable than their gauche conformation. The stability of the anti conformation compared to the gauche conformation increases from compound 1 to compound 4. The NBO analysis of donor–acceptor (σ → σ*) interactions showed that the generalized anomeric effect (GAE) is in favor of the gauche conformation of compound 1. Contrary to compound 1, GAE is in favor of the anti conformations of compounds 2–4. The GAE values calculated (i.e., GAE_anti − GAE_gauche) increase from compound 1 to compound 4. On the other hand, the calculated dipole moment values for the gauche conformations decrease from compound 1 to compound 4. In the conflict between the GAE and dipole moments, the former succeeded in accounting for the increase of the anti conformation stability from compound 1 to compound 4. There is a direct correlation between the calculated GAE, ∆[r _c–c(G) − r _c–c(A)] and ∆[r _c–x(A) − r _c–x(G)] parameters. The correlations between the GAE, bond orders, total steric exchange energies (TSEEs), ΔG _{Anti–Gauche}, ΔG ^‡(Gauche → Gauche′, C _2v), ΔG ^‡(Anti → Gauche, C ₂), dipole–dipole interactions, structural parameters, and conformational behaviors of compounds 1–4 have been investigated.     

Microwave-Assisted Minutes Synthesis of Bioactive Phenylbutanoids Occurring in <Emphasis Type="Italic">Zingiber cassumunar</Emphasis>

Microwave-assisted condensation of benzaldehyde (3a,b) with acetone in aqueous sodium hydroxide adsorbed on basic alumina provides phenylbutenone (4a–4b) in 68–71% yield within 4 min, which upon further reduction with sodium borohydride and basic alumina gives phenylbutenol (5a,b) in 91–94% yield within 2 min. Dehydration of 5 with anhydrous copper (II) sulfate gives phenylbutadiene (1a,b), a metabolite of Zingiber cassumunar, within 3 min in 42–48% yield, respectively. All the steps involve environmental friendly solvents and reagents, mild reaction conditions, and overall formation of product 1a,b from 3a,b in 34–38% yield within 9 min under microwave irradiation. __________ Published in Khimiya Prirodnykh Soedinenii, No. 4, pp. 300–302, July–August, 2005.     

Synthesis and structure of cobalt complexes [Ph3(n-Pr)P 2+ [CoI4]2? and [Ph3(n-Am)P 2+ [CoI4]2?

Complexes Ph₃(n-Pr)P₂⁺[CoI₄]²⁻ (I) and [Ph₃(n-Am)P]₂⁺ [CoI₄]²⁻ (II) were synthesized by reactions of triphenyl(alkyl)phosphonium iodide with cobalt(II) iodide in acetone. According to the X-ray diffraction data, complexes I and II consist of tetrahedral triphenyl(alkyl)phosphonium cations (for I, P-C is 1.787(4)–1.804(4) ? and CPC is 106.73(18)°–111.4(18)°; for II P-C is 1.786(6)–1.802(6) ? and CPC is 107.6(3)°–111.7(3)°) and [CoI₄]²⁻ anions (Co-I 2.5923(6)–2.6189(6) ?, ICoI 101.86(2)°–113.25(2)° for I; Co-I 2.5899(9)–2.6171(9) 107.01(3)°–110.47(3)° for II).