Extended hypervalent 5c-6e interactions: linear alignment of five C-Se---O---Se-C atoms in anthraquinone and 9-methoxyanthracene bearing arylselanyl groups at the 1,8-positions

The structures of 1,8-bis(phenylselanyl)anthraquinone (1a), 1,8-bis(phenylselanyl)-9-methoxyanthracene (2a), and 1,8-bis(phenylselanyl)anthracene (3a) are determined by X-ray crystallographic analysis, together with the derivatives. The Se-C(i) (Ph) bonds in 1a are placed on the anthraquinone plane (both type B) and the phenyl planes are perpendicular to the anthraquinone plane. The structure around the Se atoms in 2a is very close to that of 1a: the conformations of the PhSe groups are both type B. Consequently, the five C(i)-Se- - -O- - -Se-C(i) atoms in 1a and 2a align linearly. The nonbonded Se- - -O distances in 1a and 2a are 2.673-2.688 and 2.731-2.744 A, respectively, which are about 0.7 A shorter than the sum of van der Waals radii of the atoms. The extended hypervalent sigma*(C(i)-Se)- - -n(p)(O)- - -sigma*(Se-C(i)) 5c-6e interactions are strongly suggested for the origin of the linear alignment of the five atoms in 1a and 2a. The 5c-6e must be constructed by the connection of the two hypervalent n(p)(O)- - -sigma*(Se-C(i)) 3c-4e interactions through the central n(p)(O). The five C(i)-Se- - -H- - -Se-C(i) atoms never align linearly in 3a. To reveal the nature of 5c-6e in 1a and 2a, QC calculations are performed on H(a)H(b)(A)Se- - -O([double bond]CH(2))- - -(B)SeH(a')H(b') (model a) and H(a)H(b)(A)Se- - -OH(2)- - -(B)SeH(a')H(b') (model b) with the B3LYP/6-311++G(3df,2pd) method, where the nonbonded Se- - -O distances are fixed at 2.658 A. Four conformers, a (AA-cis), a (AA-trans), a (AB), and a (BB), are optimized to be stable for model a, where a (AA) shows both type A for the (A)Se-H(b) and (B)Se-H(b') bonds in model a. Three conformers, b (AA-cis), b (AB), and b (BB), are stable for model b. The bonding models in AA, AB, and BB correspond to 3c-6e, 4c-6e, and 5c-6e, respectively. The models become more stable by 42 +/- 5 kJ mol(-1), if the type A conformation of each Se-H bond changes to type B. No noticeable saturation is observed in the stabilization for each change. QC calculations are also performed on 1a-3a at the B3LYP level. Three conformers are evaluated to be stable for 1a and 2a. The relative energies of 1a (AA-trans), 1a (AB), and 1a (BB) are 0.0, -31.5, and -60.6 kJ mol(-1), respectively, and those of 2a (AA-cis), 2a (AB), and 2a (BB) are 0.0, -24.4, and -36.5 kJ mol(-1), respectively. These results demonstrate that the origin of the linear alignment of the five C-Se- - -O- - -Se-C atoms in 1a and 2a is the energy lowering effect by the extended hypervalent 5c-6e interactions of the sigma*(C-Se)<--n(p)(O)-->sigma*(Se-C) type. The pi-conjugation between pi(C[double bond]O) and n(pz)(Se) through the pi-framework of anthraquinone must also contribute to stabilize the BB structure of 1a, where z is the direction perpendicular to the anthraquinone plane.     

Neutral helium compounds: theoretical evidence for a large class of polynuclear complexes

Ab initio calculations at the MP2 and CCSD(T) levels of theory disclose the conceivable existence of neutral complexes containing up to four helium atoms. These species are formally obtained by replacing the hydrogen atoms of parent molecules such as CH(4), SiH(4), NH(3), PH(3), H(2)O, H(2)S, C(2)H(2), C(2)H(4), and C(6)H(6) with -NBeHe moieties, which behave as monovalent functional groups containing helium. The geometries and vibrational frequencies of these M(NBeHe)(n) (n>1; M=central moiety) polyhelium complexes have been investigated at the MP2(full)/6-31G(d) level of theory, and their stability with respect to the loss of helium atom(s) has been evaluated by means of single-point calculations at the CCSD(T)/6-311G(d,p) level of theory. Molecules such as H(n)C(NBeHe)(4-n) and H(n)Si(NBeHe)(4-n) (n=0-3), C(2)(NBeHe)(2), and ortho-, meta-, and para-C(6)H(4)(NBeHe)(2) were invariably characterized as energy minima, and were found to be stable with respect to the loss of helium atom(s) by approximately 4-5 kcal mol(-1). On the other hand, species such as C(2)(NBeHe)(4) and C(6)(NBeHe)(6) were characterized as high-order saddle points on the potential-energy surface, and were unstable with respect to helium atom(s) loss owing to the bending motion of the -NBeHe groups. The molecules containing N, P, O, or S as the central atom also showed a variable topology and include second-order saddle points such as S(NBeHe)(2), third-order saddle points such as HN(NBeHe)(2), but also minimum-energy structures such as O(NBeHe)(2) and HP(NBeHe)(2), which are also stable by approximately 5 kcal mol(-1) with respect to the helium atom(s) loss. These results suggest the conceivable existence of an, in principle, very large class of M(NBeHe)(n) (n>1) polyhelium complexes, whose stability may be substantially affected by the nature and the size of the central moiety M. Atoms-in-Molecules (AIM) calculations on selected species invariably suggest that, in our investigated M(NBeHe)(n) (n>1) compounds, the beryllium-helium interaction is essentially electrostatic.     

Synthesis and Reactivity of Functionalized Binary and Ternary Thiometallate Complexes [(RT)4S6], [(RSn)3S4]2−, [(RT)2(CuPPh3)6S6], and [(RSn)6(OMe)6Cu2S6]4− (R=C2H4COOH,CMe2CH2COMe; T=Ge,Sn)

Caged chalcogens : A series of novel, functionalized T_nS_m cages (T=Ge, Sn; n/m=4:6, 3:4) with terminal COO(H) or COMe groups were synthesized and show further reactivity toward Cu^I complexes (an example of which is shown here) and to hydrazines. This led to the generation of functionalized Cu/T/S clusters or the formation of Schiff bases at the C?O groups, respectively, with or without further fragmentation of the T/S core.

     

Rationalization of the behavior of M2(CH3CS2)4I (M = Ni,Pt) chains at room temperature from periodic density functional theory and ab initio cluster calculations

The electrical conductivities and plausible charge‐ordering states in the room temperature (r.t.) phase for MMX chains [Ni₂(dta)₄I]_∞ and [Pt₂(dta)₄I]_∞ (dta = CH₃CS) have been analyzed with periodic density functional theory (DFT) and correlated ab initio calculations combined with the effective Hamiltonian theory. Periodic DFT calculations show a more delocalized nature of the ground state in [Pt₂(dta)₄I]_∞ compared to [Ni₂(dta)₄I]_∞, which features a rather large energy gap between the occupied and empty bands, and charge polarized dimer units. A larger electrical conductivity for the Pt chain can be expected, especially because the Fermi level lies within a band with contributions from Pt and I orbitals. Electronic structure parameters extracted from ab initio cluster calculations show that the large difference between the observed conductivities at 300 K for Ni and Pt compounds, of 3 orders of magnitude, cannot be explained from the parameters extracted from an embedded M₂(dta)₄I₂ dimer fragment alone. When tetramer fragments are considered, we observe that the interdimer transfer integral (t) between neighboring M₂ units connected by an iodine atom at correlated level is comparable in both chains. On the other hand, the energy to transfer an electron from a dimer to the neighboring one (Coulomb repulsion U) is three times larger in the Ni compound with respect to the Pt chain, in line with the poor conductivity of the former. The electronic structure of the M₄(dta)₈I₃ fragment points to an alternate charge‐polarization state for Ni and an average valence state for Pt when the r.t. X‐ray structure is considered. © 2012 Wiley Periodicals, Inc.     

Nature and importance of three-body interactions in the (H2O)2HCl trimer

 The nature and importance of nonadditive three-body interactions in the (H₂O)₂HCl cluster have been studied by the supermolecule coupled-cluster method and by symmetry-adapted perturbation theory (SAPT). The convergence of the SAPT expansion was tested by comparison with the results obtained from the supermolecule coupled-cluster calculations including single, double, and noniterative triple excitations [CCSD(T)]. It is shown that the SAPT results reproduce the converged CCSD(T) results within 3% at worst. The SAPT method has been used to analyze the three-body interactions for various geometries of the (H₂O)₂HCl cluster. It is shown that the induction nonadditivity is dominant, but it is partly quenched by the first-order Heitler–London-type exchange and higher-order exchange–induction/deformation terms. This implies that the classical induction term alone is not a reliable approximation to the nonadditive energy and that it will be difficult to approximate the three-body potential for (H₂O)₂HCl by a simple analytical expression. The three-body energy represents as much as 21–27% of the pair CCSD(T) intermolecular energy. Received: 15 September 1999 / Accepted: 3 February 2000 / Published online: 2 May 2000     

Synthesis and Crystal Structure of the Binuclear Complex [Pr2(C10H8N2O4)2(C10H9N2O4)2(H2O)4]·3H2O·C6H6

The binuclear praseodymium(III) complex with N‐(1‐carboxyethylidene)‐salicylhydrazide (C₁₀H₁₀N₂O₄, H₂L) was prepared in H₂O‐C₂H₅OH mixed solution, and the crystal structure of [Pr₂L₂(HL)₂(H₂O)₄]·3H₂O·C₆H₆ was determined by X‐ray single crystal diffraction. The crystal complex crystallizes in the triclinic system with space group P‐1, and in the structure each Pr atom is 9‐coordinated by carboxyl O and acyl O and azomethine N atoms of two tridentate ligands to form two stable five‐membered rings sharing one side in keto‐mode and two water molecules. The coordination polyhedron around Pr³⁺ was described as a monocapped square antiprism geometry. In an individual molecule, four tridentate ligands were coordinated by two negative univalent (HL) and two bivalent forms (L) respectively. Two negative univalent ligands were coordinated via μ₂‐bridging mode.     

Prevalence of the alkyl/phenyl-folded conformation in benzylic compounds C6H5CH2-X-R (X=O,CH2, CO,S, SO,SO2): significance of the CH/pi interaction as evidenced by high-level ab initio MO calculations

Ab initio MO calculations were carried out to examine the conformational energies of various benzylic compounds C(6)H(5)CH(2)XR (X=O, CH(2), CO, S, SO, SO(2); R=CH(3), C(2)H(5), iC(3)H(7), tC(4)H(9)) at the MP2/6-311G(d,p)//MP2/6-31G(d) level. Rotamers with R/Ph in gauche relationship are generally more stable than the R/Ph anti rotamers. In these stable geometries, the interatomic distance in the interaction of alpha- or beta-CH in the alkyl group and the ipso-carbon atom of the phenyl ring is short. The computational results are consistent with experimental data from supersonic molecular jet spectroscopy on 3-n-propyltoluene and NMR and crystallographic data on structurally related ketones, sulfoxides, and sulfones. In view of this, the alkyl/phenyl-congested conformation of these compounds has been suggested to be a general phenomenon, rather than an exception. The attractive CH/pi interaction has been suggested to be a dominant factor in determining the conformation of simple aralkyl compounds.     

Analysis of Nascent Rotational Energy Distributions and Reaction Mechanisms of the Gas‐Phase Radical–Radical Reaction O(3P)+(CH3)2CH→C3H6+OH

This paper reports on the gas‐phase radical–radical dynamics of the reaction of ground‐state atomic oxygen [O(³P), from the photodissociation of NO₂] with secondary isopropyl radicals [(CH₃)₂CH, from the supersonic flash pyrolysis of isopropyl bromide]. The major reaction channel, O(³P)+(CH₃)₂CH→C₃H₆ (propene)+OH, is examined by high‐resolution laser‐induced fluorescence spectroscopy in crossed‐beam configuration. Population analysis shows bimodal nascent rotational distributions of OH (X²Π) products with low‐ and high‐N′′ components in a ratio of 1.25:1. No significant spin–orbit or Λ‐doublet propensities are exhibited in the ground vibrational state. Ab initio computations at the CBS‐QB3 theory level and comparison with prior theory show that the statistical method is not suitable for describing the main reaction channel at the molecular level. Two competing mechanisms are predicted to exist on the lowest doublet potential‐energy surface: direct abstraction, giving the dominant low‐N′′ components, and formation of short‐lived addition complexes that result in hot rotational distributions, giving the high‐N′′ components. The observed competing mechanisms contrast with previous bulk kinetic experiments conducted in a fast‐flow system with photoionization mass spectrometry, which suggested a single abstraction pathway. In addition, comparison of the reactions of O(³P) with primary and tertiary hydrocarbon radicals allows molecular‐level discussion of the reactivity and mechanism of the title reaction.     

Synthesis of the anisobidentate compound bis(2-amino-cyclopent-1-ene-carbodithioate)diethyltin (IV). Experimental and theoretical study

The bis(2-amino-1-cyclopentenecarbodithioate)diethyltin (IV) compound (1) was synthesized by reacting diethyltin (IV) chloride with two equivalents of sodium 2-amino-1-cyclopentenecarbodithioate. The structure of (1) was determined by FT-IR and multinuclear magnetic resonance (¹H, ¹³C, ¹¹⁹Sn) spectroscopy, mass spectrometry and X-ray diffraction methods. The geometry obtained around Tin is a skewed trapezoidal bipyramid with both organic residues in mutual trans-positions. To study the coordination of Tin, theoretical calculations at Hartree-Fock (HF) level were carried out. Results for relativistic, quasi-relativistic and non-relativistic pseudopotentials are reported. The concept of local bond order is defined and applied to quantify the weak local interaction between the thiocarbonyl sulfur atom and Tin.     

ChemInform Abstract: Metal-Metal Bonding and Charge Localization in (Ru2X9)n-, X: Cl or Br; n = 1, 2, 3, 4. A Spectroelectrochemical Study

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

QTAIM and stress tensor interpretation of the (H2O)5 potential energy surface

Using the quantum theory of atoms in molecules a near complete combined directed spanning quantum topology phase diagram (QTPD) was constructed from the nine (H₂O)₅ reaction‐pathways and five unique Poincaré–Hopf solutions that were found after an extensive search of the MP2 potential energy surface. Two new energy minima that were predicted from earlier work are found and include the first (H₂O)₅ conformer with a 3‐D_QT quantum topology. The stress tensor Poincaré–Hopf relation indicated a preference for 2‐D_QT (H₂O)₅ topologies as well as the presence of coupling between shared‐shell O? H BCPs to the hydrogen‐bond BCPs that share an H NCP. The complexity of the near complete combined QTPD was explained in terms of the O…O bonding interactions that were found in six of the nine (H₂O)₅ reaction‐pathways and for all points of the combined QTPD. The stabilizing role of the O…O bonding interactions from the values of the total local energy density was explored. © 2016 Wiley Periodicals, Inc.     

Interactions with ATP, DNA Cleavage and Anti-tumor Activities of Complexes with Anions [Mo（V）O2（O2CeH4）2]^3-, [Mo（Ⅴ）0.5W（Ⅵ）0.5O2（O2C6H4）2]^2.5- and [W（Ⅵ）O2（O2C6H4）2]^2-

(NH3CH2CH2NH2)3[Mo(Ⅴ)O2(O2C6H4)2] (1), (NH3CH2CH2NH2)2.5[Mo(Ⅴ)o.sW(Ⅵ)o.502(O2C6H4)2] (2) and(NH3CH2CH2NH2)2[VC(Ⅵ)O2(O2C6H4)2] (3) were synthesized, structurally characterized by X-ray diffraction analysis, and studied on their interactions with ATP, their DNA cleavage activities and antitumor properties. The redox state of molybdenum was not changed on going from crystal to aqueous solutions in complexes 1 and 2, while tungsten underwent reduction from W(VI) to W(V) in complexes 2 and 3. ATP promoted the oxidation of both molybdenum and tungsten from M(Ⅴ) to M(Ⅵ) and the hydrolysis of catecholate ligands in solution consisting of ATP and the complexes. Complex 1 possesses fairly good activity to DNA cleavage and against tumor S180 in mice, and is more effective than the control drug cyclophosphamide under the identical conditions. However, complexes 2 and 3 exhibited marginal effectiveness. The effectiveness of anti-tumor of the complexes was related positively to their DNA cleavage activities and their hydrolysis of catecholate ligands.     

Optical spectroscopy of (C2H5NH3)2CdCl4:Cu2+ under pressure: Study of Cu2+ local structure from theoretical calculations

The variations experienced by the energy E_u(π) of the e_u(π)→b_1g (～x²–y²) charge‐transfer transition of (C₂H₅NH₃)₂CdCl₄:Cu²⁺ upon pressure in the 0‐ to 40‐kbar range have been measured at room temperature by means of a sapphire anvil cell. These data reveal that E_u(π) undergoes a red shift of 1400 cm^?1 on passing from ambient pressure to 40 kbars. To understand this puzzling result theoretical calculations of ?E_u(π)/?R_eq and ?E_u(π)/?R_ax have been performed where R_eq and R_ax mean the equatorial and axial Cu²⁺–Cl^? distances of the elongated CuCl₆^4? complex, respectively. All results indicate that ?E_u(π)/?R_eq and ?E_u(π)/?R_ax for R_eq=228 pm and R_ax=297 pm are indeed negative. Moreover ab initio complete active space self‐consistent field (CASSCF/CASPT2) and density functional calculations lead to ?E_u(π)/?R_ax values, which are about 10 times smaller than those of ?E_u(π)/?R_eq. From the ensemble of experimental and theoretical results, it is concluded that a pressure of 40 kbars gives rise to a decrement of ≈25 pm of the axial distance and at the same time to an increase of ≈7 pm of the equatorial one. It is stressed that the present study on a diluted Jahn–Teller impurity lies far beyond the current possibilities of X‐ray absorption structure techniques. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001     

Theoretical study on structures and vibrational spectra of M+(H2O)Ar (M = Cu,Ag, Au)

A theoretical study on the structures and vibrational spectra of M⁺(H₂O)Ar_0‐1 (M = Cu, Ag, Au) complexes was performed using ab initio method. Geometrical structures, binding energies (BEs), OH stretching vibrational frequencies, and infrared (IR) absorption intensities are investigated in detail for various isomers with Ar atom bound to different binding sites of M⁺(H₂O). CCSD(T) calculations predict that BEs are 14.5, 7.5, and 14.4 kcal/mol for Ar atom bound to the noble metal ion in M⁺(H₂O)Ar (M = Cu, Ag, Au) complexes, respectively, and the corresponding values have been computed to be 1.5, 1.3, and 2.1 kcal/mol when Ar atom attaches to a H atom of water molecule. The former structure is predicted to be more stable than the latter structure. Moreover, when compared with the M⁺(H₂O) species, tagging Ar atom to metal cation yields a minor perturbation on the IR spectra, whereas binding Ar atom to an OH site leads to a large redshift in OH stretching vibrations. The relationships between isomers and vibrational spectra are discussed. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011     

ChemInform Abstract: Spectroscopic and Structural Studies of Difluorophosphoryl Azide F2P(O)N3, Difluorophosphoryl Isocyanate F2P(O)NCO,and Difluorophosphoric Acid Anhydride,F2(O)POP(O)F2.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

Reaction of the Pincer‐type Ligand {2, 6‐[P(O)(OEt)2]2‐4‐tert‐Bu‐C6H2}— with [Ph3C]+[PF6]—. Unprecedented Rearrangement and Carbon‐Carbon Bond Formation

The reaction of the organolithium derivative {2, 6‐[P(O)(OEt)₂]₂‐4‐tert‐Bu‐C₆H₂}Li ( 1 ‐Li) with [Ph₃C]⁺[PF₆]^— gave the substituted biphenyl derivative 4‐[(C₆H₅)₂CH]‐4′‐[tert‐Bu]‐2′, 6′‐[P(O)(OEt)₂]₂‐1, 1′‐biphenyl ( 5 ) which was characterized by ¹H, ¹³C and ³¹P NMR spectroscopy and single crystal X‐ray analysis. Ab initio MO‐calculations reveal the intramolecular O···C distances in 5 of 2.952(4) and 2.988(5)Å being shorter than the sum of the van der Waals radii of oxygen and carbon to be the result of crystal packing effects. Also reported are the synthesis and structure of the bromine‐substituted derivative {2, 6‐[P(O)(OEt)₂]₂‐4‐tert‐Bu]C₆H₂}Br ( 9 ) and the structure of the protonated ligand 5‐tert‐Bu‐1, 3‐[P(O)(OEt)₂]₂C₆H₃ ( 1 ‐H). The structures of 1 ‐H, 5 , and 9 are compared with those of related metal‐substituted derivatives.     

Syntheses and Properties of Tetrakis(pentafluorophenyl)tellurium,Te(C6F5)4, and Related Compounds — Single Crystal Structures of Tris(pentafluorophenyl)tellurium Bromide,Te(C6F5)3Br,Tris(pentafluorophenyl)tellurium Trifluoromethanesulfonate, [Te(C6F5)3][OSO2CF3], and Bis(pentafluorophenyl)tellurium Oxide,Te(C6F5)2O

Te(C₆F₅)₄ was prepared from the reactions of TeCl₄ or Te(C₆F₅)₂Cl₂ with Grignard reagents or AgC₆F₅ in moderate to good yields. Substitution reactions with Me₃SiX (X = Cl, Br, OSO₂CF₃), with equimolar amounts of Br₂, with AgNO₃ and with H[BF₄] or BF₃·OEt₂ yielded the Te(C₆F₅)₃X derivatives (X = Cl, Br, OSO₂CF₃, NO₃, BF₄). Oxidation reactions of Cd, Hg, and Pd⁰ complexes led to Te(C₆F₅)₂ and the corresponding bis(pentafluorophenyl) derivatives M(C₆F₅)₂ (M = Cd, Hg, Pd) and with InBr to In(C₆F₅)₂Br. From very slow hydrolysis of Te(C₆F₅)₄ the oxide Te(C₆F₅)₂O was prepared. The thermal decomposition, the NMR and mass spectra of the partially new compounds are discussed. The crystal structures of Te(C₆F₅)₃Br (monoclinic, P2₁/a, Z = 4), [Te(C₆F₅)₃][OSO₂CF₃] (monoclinic, P2₁/n, Z = 16) and [Te(C₆F₅)₂O]₂ (triclinic, P1¯, Z = 2) were determined.     

Application in the cyclohexane oxidation of a scorpionate oxovanadium(IV) complex: synthesis,structure, and properties of VO(C5H7O2)(BC9H7N6I3)

An oxovanadium(IV) complex, VO(C₅H₇O₂)(BC₉H₇N₆I₃), derived from hydrotris(4-iodinpyrazolyl)borate was designed and synthesized at room temperature in methanol. The complex was characterized by elemental analysis, IR spectra, UV-Vis spectroscopy, and single-crystal X-ray diffraction. The structural analysis shows that the vanadium(IV) center possesses a distorted-octahedral geometry with a N₃O₃ core, containing a tridentate hydrotris(4-iodinpyrazolyl)borate with nitrogen as three donors. The complex is the first structurally characterized example of a vanadium(IV) complex with hydrotris(4-iodinpyrazolyl)borate. It was used as a catalyst for cyclohexane oxidation under mild conditions and the effects of a variety of factors such as amount of acid and H₂O₂, the kind of solvent, as well as temperatures were evaluated; the maximum turnover number value reaches 321.     

乙醇-水分子团簇C2H5OH(H2O)n (n=1-9)稳定结构的量子化学研究

采用密度泛函理论B3LYP方法, 在B3LYP/6-311++G(2d,2p)//B3LYP/6-311++G(d,p)基组水平上对乙醇-水分子团簇(C₂H₅OH(H₂O)_n (n=1-9))的各种性质进行研究, 如: 优化的几何构型、结构参数、氢键、结合能、平均氢键强度、自然键轨道(NBO)电荷分布、团簇的生长规律等. 结果表明, 从二维(2-D)环状结构到三维(3-D)笼状结构的过渡出现在n=5的乙醇-水分子团簇中. 此外, 利用团簇结合能的二阶差分、形成能、能隙等性质, 发现在n=6时乙醇-水分子团簇的最低能量结构稳定性较好, 可能为幻数结构. 最后, 为了进一步探讨氢键本质, 将C₂H₅OH(H₂O)_n (n=2-9)最低能量结构的各种性质与纯水分子团簇(H₂O)_n (n=3-10)比较, 结果表明前者与后者中的水分子之间氢键相似.