Structures, relative stability and dissociation of [Si,N,C,O]2+isomers

Fifteen isomers of [Si,N,C,O]2+ system are obtained at UB3LYP/6-311G(d) and UCCSD(T)/6-311+G(2df) (single-point) levels. The analyses are made for predicting the structures of optimized isomers, while ionic fragments with lower energies are suggested. The calculatedresults indicate that linear isomer SiNCO2+(2П) is thermodynamically the most stable species in [Si,N,C,O]2+ system, followed by linear SiOCN2+ (2П), SiCNO2+ (2П), and SiC(NO) (2A") with NCO three-membered ring. The order of stability of several kinetically stable isomers is SiNCO2 >SiCNO2+ (2П)>SiOCN2+ >SiC(NO)2+>OSiNC2+ (2П). The obtained results by analyzing the isomerizations and ionic fragment patterns show that the signal peaks of [Si,N,C,O]2+ are attributed to the contribution of linear SiNCO2+ species, which is metastable and can dissociate to the ionic fragments in the mass spectrometry experiments.     

Theoretical study on the [Si, C, N, O] potential energy surface

The structures, energetics, spectroscopies, and stabilities of the doublet [Si, C, N, O] radical are explored at the density functional theory and ab initio levels. Sixteen isomers are located, connected by 29 interconversion transition states. At the CCSD(T)/6-311+G(2df)//QCISD/6-311G(d)+ZPVE level, the lowest lying isomer is a linear SiNCO 1 (0.0 kcal/mol) mainly featuring a cumulene | . Si = N = C = O. The second and third low-lying isomers are bent OSiCN 2 (8.8) and bent OSiNC 3 (11.1), respectively. All the three low-lying isomers 1, 2, 3, and another high-lying species 5 (75.4) with a linear SiCNO structure are shown to have considerable kinetic stability and may be experimentally observable. The predicted results of isomers 1 and 2 are consistent with the previous mass spectrometry experiments. Moreover, the fourth low-lying species SiOCN 4 (23.9) with bent structure is expected to be observable in low-temperature environments. The bonding nature of the five isomers 1, 2, 3, 4, and 5 is analyzed. The calculated results are compared with those of the analogous molecules C(2)NO and Si(2)NO. Implications in interstellar space and N,O-doped SiC vaporization processes are also discussed.     

Structures and stability of isomers of [C,N,N,P] system

Interstellar species have been of interest to chemists because of their unusual structures and reactivities, such as CN, NP, CP, and SiN, which have been identi-fied in interstellar medium[1―4] and well characterized for the formation, structures, spectr…     

Structures and stability of isomers of [Si,N,N,P] system

Recently, silicon- and nitrogen-containing small molecules, such as SiN, SiC, SiC2, and NP, which have been identified in interstellar medium[1—3] and well characterized for the formation, structures, spec-tra, and reactivity using theoretical and experimental methods[4—8], have attracted more attentions because of their potential importance in chemical kinetics, in-terstellar chemistry, astrophysics, and material science. The systems with three, four, and five atoms, for ex-ample, Si2N, …     

A study on interaction of Be, Mg and Ca with phenylalanine: Binding energies, metal ion affinities and IR signature of complex stability

The interaction between divalent metal cations and amino acids plays an important role in many biological processes. In present report, we have examined the effect of metal cations (Be⁺⁺, Mg⁺⁺ and Ca⁺⁺) interaction on structures, binding energies (BE), metal ion affinities (MIA) and infrared (IR) spectra of phenylalanine (Phe) molecule by density functional theory (DFT) calculations at B3LYP/6-311++G(d,p) level. Nine different ground state isomers of Phe molecule have been optimized at B3LYP/6-311++G (d,p) level of theory. The relative ground state energies of these nine isomers are lying between 0.0-1.9 kcal/mol with respect to the ground state energy of most stable Phe isomer. Seven most stable complexes of Phe molecule with Be⁺⁺, Mg⁺⁺ and Ca⁺⁺ [Phe+M]⁺⁺ (M = Be⁺⁺, Mg⁺⁺ and Ca⁺⁺) were studied. The calculated values of metal ion affinity (MIA), BE and the Gibbs free energies of each [Phe+M] ⁺⁺ complexes were found to be in the order of Be⁺⁺ > Mg⁺⁺ > Ca⁺⁺. Among the seven [Phe+M]⁺⁺ complexes, the most stable conformer has charge solvation structure where the metal cations coordinated through tridentate bonds with -N, -O atoms and benzene ring (N/O/Ring). The [Phe+Be]⁺⁺ complex has maximum MIA value, 353.3 kcal/mol than that of [Phe+Mg]⁺⁺ and [Phe + Ca]⁺⁺ complexes. Thus, the complex [Phe+Be]⁺⁺ is energetically more stable than that of [Phe+Mg]⁺⁺ and [Phe + Ca]⁺⁺. The IR spectra of each seven conformers of [Phe+M]⁺⁺ complexes have been also calculated. The wavnumber position of (-CO) stretching mode was used to determine the charge/salt bridge structures of the [Phe+M]⁺⁺ complex. The most stable [Phe+M]⁺⁺ complex has been also verified through the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) analysis.     

Theoretical study on structures and stability of Si2CP isomers

The structures, energetics, spectroscopies, and isomerization of various doublet Si2CP species are explored theoretically. In contrast to the previously studied SiC2N and SiC2P radicals that have linear SiCCN and SiCCP ground states, the title Si2CP radical has a four-membered-ring form cSiSiPC 1 (0.0 kcal/mol) with Si-C cross-bonding as the ground-state isomer at the CCSD(T)/6-311G(2df)//B3LYP/6-311G(d)+ZPVE level, similar to the Si2CN radical. The second low-lying isomer 2 at 11.6 kcal/mol has a SiCSiP four-membered ring with C-P cross-bonding, yet it is kinetically quite unstable toward conversion to 1 with a barrier of 3.5 kcal/mol. In addition, three cyclic species with divalent carbene character, i.e., cSiSiCP 7, 7' with C-P cross-bonding and cSiCSiP 8 with Si-Si cross-bonding, are found to possess considerable kinetic stability, although they are energetically high lying at 44.4, 46.5, and 41.4 kcal/mol, respectively. Moreover, a linear isomer SiCSiP 5 at 44.3 kcal/mol also has considerable kinetic stability and predominantly features the interesting cumulenic /Si=C=Si=P/* form with a slight contribution from the silicon-phosphorus triply bonded form /Si=C*-Si[triple bond]P/. The silicon-carbon triply bonded form *Si[triple bond]C-Si[triple bond]P/ has negligible contribution. All five isomers are expected to be observable in low-temperature environments. Their bonding nature and possible formation strategies are discussed. For relevant species, the QCISD/6-311G(d) and CCSD(T)/6-311+G(2df) (single-point) calculations are performed to provide more reliable results. The calculated results are compared to those of the analogous C3N, C3P, SiC2N, and Si2CN radicals with 17 valence electrons. Implications in interstellar space and P-doped SiC vaporization processes are also discussed.     

Si2CN: a stable nitrogen-containing radical with cyclic ground state

The structures and isomerization of Si(2)CN species are explored at density functional theory and ab initio levels. Fourteen minimum isomers are located connected by 23 interconversion transition states. At the coupled-cluster single double (CCSD)(T)/6-311+G(2df)//QCISD/6-311G(d) +zero-point vibrational energies level, the thermodynamically most stable isomer is a four-membered ring form cSiSiCN 1 with Si-C cross bonding. Isomer 1 has very strong C-N multiple bonding characters, formally suggestive of a radical adduct between Si(2) and CN. Such a highly pi-electron localization can effectively stabilize isomer 1 to be the ground state. The second low-lying isomer is a linear form SiCNSi 5 (9.8 kcal/mol above 1) with resonating structure among [Si=C-*N=Si], *[Si=C=N=Si], and [Si=C=N-Si*]* with the former two bearing more weight. The species 1 and 5 have very high kinetic stability stabilized by the barriers of at least 25 kcal/mol. Both isomers should be experimentally or astrophysically observable. In light of the fact that no cyclic nitrogen-containing species have been detected in space, the cyclic species 1 could be a very promising candidate. The calculated results are compared to those of the analogous molecules C(3)N, C(3)P, SiC(2)N, and SiC(2)P. Implications of Si(2)CN in interstellar and N-doped SiC vaporization processes are also discussed.     

Quantum chemical topology: The electronic structure of the alkaline nitrites MONO (M = Li,Na, K) studied by means of topological analysis of the electron localization function

In the search of the protocovalent bonding, previously recognized in the nitrous acid (HONO), a nature of the chemical bonds in the alkaline nitrites MONO (M = Li, Na, K) has been studied by means of the topological analysis of the Electron Localization Function (ELF) and Electron Localizability Indicator (ELI‐D). Calculations carried out with the B3LYP and MP2(full) methods, in conjunction with the aug‐cc‐pVTZ and 6‐311++G(3df,3pd) basis sets, revealed the cis (C_2v, more stable) and trans (C_s) isomers as minima on PES. Alkaline nitrites consist of the alkali metal cation M^δ+ interacting, mainly via electrostatic forces, with the nitrite anion [ONO]^δ− (δ ≈ 1e). The covalent N O bonds are characterized by disynaptic basins V(N,O) with the basin populations: 1.58÷1.62e for cis‐M^δ+[ONO]^δ− but 1.39÷1.49e for single N O bond and 1.81÷1.87e for formally double NO bond in trans M^δ+[O NO]^δ−. The protocovalent nitrogen–oxygen bond has not been observed. The N O bonds are slightly polarized towards the nitrogen atom with the polarity index p_NO ≤ 0.12. Two different sets of the hybrid (Lewis) structures are compared leading to different pictures of the bonding. According to NBO data there is a delocalization between the single N O and double NO type bonds, meanwhile results of the ELF analysis emphasize an electron delocalization between the single N O and ionic O⁻N⁺ hybrids. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010     

Crystal structure,electrochemical and photochemical studies of the trans-[Fe(cyclam)(NO)Cl]Cl2 complex (cyclam = 1,4,8,11-tetraazacyclotetradecane)

The trans-[Fe(cyclam)(NO)Cl]Cl₂ complex was synthesized by the reaction of cis-[Fe(cyclam)Cl₂]Cl with NO gas. The X-ray structure of the complex showed that the [Fe–NO] moiety is linear, consistent with the NO⁺ character of the nitric oxide ligand. This suggestion was reinforced by the IR data, which showed the νNO at 1888 cm⁻¹. The cyclic voltammogram of the trans-[Fe(cyclam)(NO)Cl]²⁺ complex presented three electrochemical processes at −0.70, 0.08 and 0.40 V versus Ag/AgCl. The first and last redox processes are centered at the NO ligand, whereas the second is characteristic of the generated aqua species, trans-[Fe(cyclam)Cl(H₂O)]²⁺. Upon irradiation at 330 nm, pH 3.4, the title complex releases the NO moiety with the concomitant generation of the trans-[Fe(cyclam)(H₂O)Cl]⁺ complex as suggested by electronic and IR spectroscopy as well as by cyclic voltammetry technique.     

Reactivity of the Re-NO centre: Proton induced oxidation of Re(NO)2+ to Re(NO)3+. Synthesis and characterisation of some Re(II) thiocyanato-halogenonitrosyl complexes

The Re(NO)²⁺ moiety as [Re(NO)(NCS)₃H₂O]⁻ or [Re(NO)(NCS)₂(L-L)H₂O]· [L-L = phen (1,10-phenanthroline) or bipy (2,2′-bipyridine)] undergoes proton-induced oxidation reaction with HX (X = Cl, Br) to produce a Re(NO)³⁺ moiety. The spectral and physico-chemical data suggest that the anionic complex is 5 coordinate and the neutral one is 6 coordinate with axial NO group and two NCS ligands intrans-equatorial positions. The complex, [Re(NO)(NCS)₂(phen)Br]·H₂O shows complicated magnetic behaviour which is discussed in the paper. The ESR spectrum of this compound shows typical rhenium hyperfines and <g>-tensor anisotropy compatible with the loss of axial symmetry. However, the spectrum of [Re(NO)(NCS)₂Br₂]⁻ quite reasonably shows axial symmetry, other features being grossly comparable to the L-L compounds. The anionic species and the neutral L-L complex show irreversible one-electron oxidation waves at different voltages. This may correspond to a conversion of Re(NO)³⁺ to Re(NO)⁴⁺ in both the cases. Interestingly enough, only the neutral complexes exhibit an irreversible reduction wave due probably to a conversion of Re(NO)³⁺ to Re(NO)²⁺.     

Theoretical study on structures and stabilities of [H,Ge,C,N

Theoretical investigations are performed for the first time on the simplest hydrogenated germanium cyanide [H,Ge,C,N], whose analogs [H,C(2),N] and [H,Si,C,N] have been detected in space and laboratory, respectively. The detailed potential energy surfaces in both singlet and triplet states are constructed at the CCSD(T)/6-311+G(3df,2p)//B3LYP/6-31G(d)+ZPVE level, including 18 minimum isomers and 26 interconversion transition states. The former three low-lying and kinetically stabilized isomers are HGeCN (1)1 (0.0 kcal/mol), HGeNC (1)2 (5.1 kcal/mol), and cyclic cCHNGe(1)7 (11.1 kcal/mol). In addition, five isomers HCNGe (1)3 (33.8), HNCGe (1)5 (29.8), cNHCGe (1)8 (37.9), HGeCN (3)1 (30.1), and HNCGe (3)5 (26.5) each have considerable barriers, despite their high energies. Future laboratory characterization and astrophysical detection of the eight [H,Ge,C,N] isomers, especially the former three low-lying species (1)1, (1)2, and (1)7, are highly recommended. The accurate spectroscopic data at the QCISD/6-311G(d,p) level are provided. For some species, the CBS-QB3 calculations are also performed. Wherever possible, comparisons with the analogous [H,C(2),N] and [H,Si,C,N] are made on the structural, energetic, and bonding properties.     

Photochemical Behavior of Platinum(II) and Palladium(II) Complexes of 4,4′-Dimethyl-2,2′-Bipyridine

Several mixed-ligand complexes of formula [MX 2 (MBPY)] {where M is Pd(II) or Pt(II); X is Cl m , I m , N 3 m or NO 2 m and MBPY is 4,4'-dimethyl-2,2'-bipyridine} have been prepared. The UV-Vis spectra of these complexes were found to show a low-lying MLCT band and on irradiation at the MLCT band these complexes sensitize the oxidation of 2,2,6,6-tetramethyl-4-piperidinol (XH) in N , N -dimethylformamide (DMF) to 4-hydroxy-2,2,6,6-tetramethyl-1-piperidinoloxy free radical (XO). This photo-oxidation reaction involves singlet molecular oxygen ( 1 O 2 ) as an intermediate and its presence was confirmed by quenching studies using bis(diethyldithiocarbamato)nickel(II) [Ni(DDTC) 2 ], a well-known 1 O 2 quencher. The ability of the complexes to photosensitize the above photo-oxidation reaction follows the order: [Pt ( N 3 ) 2 ( MBPY ) ] ( 2 ) ～ [Pt ( NO 2 ) 2 ( MBPY ) ] ( 3 ) > [PtCl 2 ( MBPY ) ] ( 4 ) > [PtI 2 ( MBPY ) ] ( 1 ) > [Pd ( NO 2 ) 2 ( MBPY ) ] ( 7 ) ～ [Pd ( N 3 ) 2 ( MBPY ) ] ( 6 ) > [PdCl 2 ( MBPY ) ] ( 8 ) > [PdI 2 ( MBPY ) ] ( 5 ), which reflects the nature of the metal ion and the nature of the ligands present in the complexes.     

Atmospheric pressure chemical ionization and fragmentation of aminomonosaccharides in H2O and D2O

Aminomonosaccharides (glucosamine, galactosamine, and mannosamine) in H₂O and D₂O were ionized by atmospheric pressure chemical ionization (APCI) and their fragmentation patterns were investigated to identify them. All the aminomonosaccharides showed the same fragment ions but their relative ion intensities were different. Major product ions generated in H₂O were [M + H]⁺, [M + H – H₂O]⁺, and [2M + H – 3H₂O]⁺, while in D₂O were [M_D6 + D]⁺, [M_D6 + D – D₂O]⁺, and [2M_D6 + D – D₂O – 2HDO]⁺. At a high fragmentor voltage above 120 V, the relative ion intensities of the major product ions showed different trends according to the aminomonosaccharides. For the use of H₂O as solvent and eluent, the order of the ion intensity ratio of [M + H – H₂O]⁺/[2M + H – 3H₂O]⁺ was galactosamine > mannosamine > glucosamine. When using D₂O as solvent and eluent, the order of the ion intensity ratios of [M_D6 + D – D₂O]⁺/[M_D6 + D]⁺ and [2M_D6 + D – D₂O – 2HDO]⁺/[M_D6 + D]⁺ was mannosamine > galactosamine > glucosamine. It was found that glucosamine, galactosamine, and mannosamine could be distinguished by the specific trends of the major product ion ratios in H₂O and D₂O. Copyright © 2009 John Wiley & Sons, Ltd.     

Discriminating alkylbenzene isomers with tandem mass spectrometry using a dielectric barrier discharge ionization source

Soft ambient ionization sources generate reactive species that interact with analyte molecules to form intact molecular ions, which allows rapid, sensitive, and direct identification of the molecular mass. We used a dielectric barrier discharge ionization (DBDI) source with nitrogen at atmospheric pressure to detect alkylated aromatic hydrocarbon isomers (C₈H₁₀ or C₉H₁₂). Intact molecular ions [M]^•+ were detected at 2.4 kV_pp, but at increased voltage (3.4 kV_pp), [M + N]⁺ ions were formed, which could be used to differentiate regioisomers by collision-induced dissociation (CID). At 2.4 kV_pp, alkylbenzene isomers with different alkyl-substituents could be identified by additional product ions: ethylbenzene and -toluene formed [M-2H]⁺, isopropylbenzene formed abundant [M-H]⁺, and propylbenzene formed abundant C₇H₇⁺. At an operating voltage of 3.4 kV_pp, fragmentation of [M + N]⁺ by CID led to neutral loss of HCN and CH₃CN, which corresponded to steric hindrance for excited state N-atoms approaching the aromatic ring (C-H). The ratio of HCN to CH₃N loss (interday relative standard deviation [RSD] < 20%) was distinct for ethylbenzene and ethyltoluene isomers. The greater the number of alkyl-substituents (C-CH₃) and the more sterically hindered (meta > para > ortho) the aromatic core, the greater the loss of CH₃CN relative to HCN was.     

Synthesis,characterization, and metal uptake of multiple functionalized immobilized-polysiloxane diamine-thiol chelating ligand derivatives

Immobilized-polysiloxane (diamine-thiol) tetraethylacetate, P-(NN-S)-TEA (where P represents [Si–O]_n polysiloxane network), was synthesized using one-pot reaction of tetraethylorthosilicate (TEOS) with 3-(ethylenediaminetriethylacetate)propyltrimethoxysilane and 3-thiolethylacetatepropyltrimethoxysilane in the presence of cetyl trimethylammonium bromide (CTAB) as a surfactant. Its ethylenediamine and diethylenetriamine modified polysiloxane (diamine-thiol)-tetrakis(N-2-aminoethylacetamide), P-(NN-S)-TEA-NN, and polysiloxane (diamine-thiol)-tetrakis(N-diethylenediamineacetamide), P-(NN-S)-TEA-NNN chelating ligand systems were also obtained. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopic (XPS), and thermogravimetric analysis (TGA) techniques have been used for establishing their structures. An elemental CHNX combustion analyzer was used to determine the mass fractions of carbon, hydrogen, nitrogen, and sulfur of samples. The metal uptake capacities results showed that the modified polysiloxane ligand systems exhibited high capacities for the uptake of divalent metal ions in the following order: Cu²⁺> Pb²⁺> Ni²⁺> Co²⁺.     

Theoretical study of the Si2NO potential energy surface

The structures, spectroscopies, and stabilities of the doublet Si₂NO radical are explored at the density functional theory (DFT) and ab initio levels. Seventeen isomers are located, connected by 26 interconversion transition states. At the CCSD(T)/6‐311+G(2df)//QCISD/6‐311G(d)+ZPVE level, three low‐lying isomers are predicted, that is, one bent species SiNSiO 3 (5.1 kcal/mol) containing the important Si?N triple bonding and two four‐membered ring isomers including cyclic cSiNSiO 1 (0.0) with Si? Si cross‐bonding with C_2v symmetry and puckered cSiNSiO 1′ (11.9) with divalent carbene character. Three low‐lying isomers 1, 1′, and 3 have reasonable kinetic stabilities and might be observable either experimentally or astrophysically. The possible formation strategies of 1, 1′, and 3 in laboratory and in space are discussed in detail. The calculated vibrational frequencies and possible formation processes of 3 are consistent with recent experimental observations. In light of the fact that no cyclic nitrogen‐containing species have been detected in space, two cyclic isomers 1 and 1′ could be promising candidates. Furthermore, the bonding nature of three isomers 1, 1′, and 3 is analyzed. The calculated results are also compared with those of the analogue C₂NO radical. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007     

Kinetics of the reaction of nitric oxide with polypyridylamine iron(II) complexes

The reactions of three polypyridylamine ferrous complexes, [Fe(TPEN)]²⁺, [Fe(TPPN)]²⁺, and [Fe(TPTN)]²⁺, with nitric oxide (NO) (where TPEN = N,N,N′,N′-tetrakis(2-pyridylmethyl)ethylenediamine, TPPN = N,N,N′,N′-tetrakis(2-pyridylmethyl)-1,2-propylenediamine, and TPTN = N,N,N′,N′-tetrakis(2-pyridylmethyl)trimethylenediamine) were investigated. The first two complexes, which are spin-crossover systems, presented second-order rate constants for complex formation reactions (k_f) of 8.4 × 10³ and 9.3 × 10³ M^?1 s^?1, respectively (pH 5.0, 25 °C, I = 0.1 M). In contrast, the [Fe(TPTN)]²⁺ complex, which is in low-spin ground state, did not show any detectable reaction with NO. k_f values are lower than those of high-spin Fe(II) complexes, such as [Fe(EDTA)]^2? (EDTA = ethylenediaminetetraacetate) and [Fe(H₂O)]²⁺, but higher than low-spin Fe(II) complexes, such as [Fe(CN)₅(H₂O)]^3? and [Fe(bipyridine)₃]²⁺. The release of NO from the [Fe(TPEN)NO]²⁺ and [Fe(TPPN)NO]²⁺ complexes were also studied, showing the values 15.6 and 17.7 s^?1, respectively, comparable to the high-spin aminocarboxylate analogs. A mechanism is proposed based on the spin-crossover behavior and the geometry of these complexes and is discussed in the context of previous publications.     

Dipole moments,structure, and transannular interactions in silatranes containing planar fragments

The method of dipole moments and theoretical calculations (DFT B3LYP/6-31G^*) were used for structural assessment of silatranes N[CH₂(RMeC₆H₂)O]₃SiR¹ containing planar fragments in the six-membered semirings. They are endo structures with transannular N→Si interaction which involves, along with nitrogen and silicon, oxygen atoms adjacent to silicon.     

预测[Si, C, S]＋和[Si, C, S]－体系的稳定异构体

采用DFT, QCISD及CCSD(T)方法分别对二重态的[Si, C, S]＋和[Si, C, S]－体系势能面进行理论计算, 用QCISD/6-311＋G(d)方法, 在[Si, C, S]＋和[Si, C, S]－体系中, 我们分别得到了2个过渡态连接的3个稳定体和2个过渡态连接的4个稳定体, 经热力学及动力学分析发现, [Si, C, S]＋体系只有二重态线性的离子[Si—C—S]＋可能稳定存在, 而[Si, C, S]－体系有二重态线性的离子[Si—C—S]－和三元环c-[SiCS]－可能稳定存在.     

金属离子(Na~+、K~+、Ca~(2+)、Mg~(2+)、Zn~(2+))与鸟嘌呤异构体配合物的稳定性

在B3LYP/6-311++G**水平上用极化连续介质模型(PCM)系统研究了金属离子(M+/2+=Na+,K+,Ca2+,Mg2+,Zn2+)和十三种鸟嘌呤异构体形成的配合物GnxM+/2+(n为鸟嘌呤异构体的编号,x表示M+/2+与鸟嘌呤异构体的结合位点)在气(g)液(a)两相中的稳定性顺序.着重探讨了液相中配合物的稳定性差异,并且从溶质-溶剂效应、结合能、形变能及异构体的相对能量等几个方面分析了造成稳定顺序发生变化的原因.报道了溶液中这五种金属离子与鸟嘌呤异构体结合形成的六种基态配合物:aG1N2,N3Na+,aG1N2,N3K+,aG1O6,N7Ca2+,aG1N2,N3Mg2+(aG1O6,N7Mg2+),aG2N3,N9Zn2+.可以看出,除了在Zn2+配合物中鸟嘌呤异构体为G2外,构成其余四种金属离子配合物的鸟嘌呤异构体都是G1,但结合位点不同.同时对气相中各类配合物稳定性也进行了系统的排序,并报道了几种较稳定的配合物,如:gG3N1,O6K+,gG5N1,O6K+,gG3N1,O6Ca2+/Mg2+,gG4O6,N7Ca2+/Mg2+.