# A Spectral-SAR Model for the Anionic-Cationic Interaction in Ionic Liquids: Application to Vibrio fischeri Ecotoxicity

^{1}

^{2}

^{3}

^{*}

## Abstract

**:**

## 1. Introduction

## 2. The Spectral-SAR Ionic Liquid (S-SAR-IL) Model

#### 2.1. S-SAR Concepts

_{0}= 1 1 ... 1 was added to account for the free correlation term in (1).

#### 2.2. S-SAR for Ionic Liquids

_{AC}. Nevertheless, its practical definition can be achieved, since the anionic-cationic norm (13) is rewritten employing the vectorial relation (11) to the scalar product between the anionic and cationic vectors

## 3. Application to Ecotoxicology

#### 3.1. The Working System

#### 3.2. Results and Discussion

- ■
- the anionic gamma path effect is marginal over the cationic alpha path – equation (19);
- ■
- the cationic and anionic beta paths decay into the gamma ionic liquid path when met together so that recording a sort of reciprocal cancellation of their effects – equation (20);
- ■
- the anionic alpha path effect is reinforcing over the cationic gamma path averaging both at the beta path level of the resulted ionic liquid – equation (21).

## 4. Conclusions

**Figure 3.**The spectral representation of the chemical-biological interaction paths across the S-SAR to the modeled endpoints of the Vibrio fischeri, according to the least (shortest) path rule within the spectral norm-correlation space applied on Table 7 data, for the cationic, anionic and resulted ionic liquid norms of Tables 3–5, for the statistic and algebraic versions of correlation factors, from up to down and left to right, respectively. The primary-alpha, secondary-beta and tertiary-gamma path hierarchies of Table 7 are indicated by decreasing the thickness of the connecting lines.

Activity | Structural predictor variables | |||||
---|---|---|---|---|---|---|

|Y〉 | |X_{0}〉 | |X_{1}〉 | ... | |X_{k}〉 | ... | |X_{M}〉 |

y_{1} | 1 | x_{11} | ... | x_{1}_{k} | ... | x_{1}_{M} |

y_{2} | 1 | x_{21} | ... | x_{2}_{k} | ... | x_{2}_{M} |

⋮ | ⋮ | ⋮ | ⋮ | ⋮ | ⋮ | ⋮ |

y_{N} | 1 | x_{N}_{1} | ... | x_{Nk} | ... | x_{NM} |

**Table 2.**The series of the ionic liquids of Figure 2 of those toxic activities

**A**= Log(EC

_{50}) on Vibrio fischeri were considered [24], with the marked values taken from [4], along structural parameters LogP, POL (Å

^{3}), and E

_{TOT}(kcal/mol) as accounting for the hydrophobicity, electronic (polarizability) and steric (total energy at optimized 3D geometry) effects, computed with the help of HyperChem program [25], for each cation and anion containing ionic liquid, respectively.

No. | NAME | A_{exp} | Log P | Polarizability | TOTAL ENERGY | |||
---|---|---|---|---|---|---|---|---|

|Y_{EXP}〉 | CAT. |X_{1}_{C}〉 | AN. |X_{1}_{A}〉 | CAT. |X_{2}_{C}〉 | AN. |X_{2}_{A}〉 | CAT. |X_{3}_{C}〉 | AN. |X_{3}_{A}〉 | ||

1. | 1-n-butylpyridinium chloride | 0.41* | 2.85 | 0.63 | 17.51 | 2.32 | −250008.14 | −285190.78 |

2. | 1-n-butylpyridinium dicyanoamide | 0.31* | 2.85 | 0.43 | 17.51 | 5.51 | −250008.14 | −147935.98 |

3. | 1-n-butyl-3-methylpyridinium dicyanoamide | −0.34* | 3.32 | 0.43 | 19.35 | 5.51 | −274222.62 | −147935.98 |

4. | 1-n-butyl-3,5-dimethylpyridinium dicyanoamide | −0.62* | 3.78 | 0.43 | 21.18 | 5.51 | −298437.03 | −147935.98 |

5. | 1-n-butylpyridinium bromide | 0.40* | 2.85 | 0.94 | 17.51 | 3.01 | −250008.14 | −1596918.25 |

6. | 1-n-butyl-3-methylpyridinium bromide | −0.25* | 3.32 | 0.94 | 19.35 | 3.01 | −274222.62 | −1596918.25 |

7. | 1-n-butyl-3,5-dimethylpyridinium bromide | −0.31* | 3.78 | 0.94 | 21.18 | 3.01 | −298437.03 | −1596918.25 |

8. | 1-n-hexyl-3-methylpyridinium bromide | −0.94* | 4.11 | 0.94 | 23.02 | 3.01 | −322641.81 | −1596918.25 |

9. | 1-n-octyl-3-methylpyridinium bromide | −2.21* | 4.90 | 0.94 | 26.69 | 3.01 | −371060.81 | −1596918.25 |

10. | 1-n-butyl-4-dimethylaminopyridinium bromide | −0.68 | 3.11 | 0.94 | 22.53 | 3.01 | −332525.97 | −1596918.25 |

11. | 1-n-butyl-3-methylimidazolium dicyanoamide | 0.67* | 0.68 | 0.43 | 17.22 | 5.51 | −260646.64 | −147935.98 |

12. | 1-n-butyl-3-methylimidazolium chloride | 0.71* | 0.68 | 0.63 | 17.22 | 2.32 | −260646.64 | −285190.78 |

13. | 1-n-butyl-3-methylimidazolium bromide | 1.01* | 0.68 | 0.94 | 17.22 | 3.01 | −260646.64 | −1596918.25 |

14. | 1-n-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide | 0.39 | 0.68 | 3.05 | 17.22 | 7.20 | −260646.64 | −1128283.62 |

15. | 1-n-hexyl-3-methylimidazolium bromide | −1.58* | 1.47 | 0.94 | 20.89 | 3.01 | −309065.84 | −1596918.25 |

16. | 1-n-octyl-3-methylimidazolium bromide | −2.37* | 2.26 | 0.94 | 24.56 | 3.01 | −357484.59 | −1596918.25 |

17. | tetrabutylammonium bromide | 0.27 | 4.51 | 0.94 | 30.91 | 3.01 | −422421.97 | −1596918.25 |

18. | hexyltriethylammonium bromide | −0.54 | 2.71 | 0.94 | 23.57 | 3.01 | −325587.25 | −1596918.25 |

19. | tetrabutylphosphonium bromide | −0.29 | 2.89 | 0.94 | 30.91 | 3.01 | −600149.62 | −1596918.25 |

20. | tributylethylphosphonium diethylphosphate | 0.07 | 2.02 | 2.63 | 27.24 | 10.53 | −551729.87 | −494172.37 |

21. | Trihexyl(tetradecyl)phosphonium bromide | 0.41 | 9.23 | 0.94 | 60.27 | 3.01 | −987499.25 | −1596918.25 |

22. | Choline bis(trifluoromethanesulfonyl)imide | 1.15 | −0.76 | 3.05 | 11.36 | 7.20 | −202450.36 | −1128283.62 |

**Table 3.**Spectral structure activity relationships (S-SAR) of the ionic liquids of Figure 2 against Vibrio fischeri toxicity, and the associated computed spectral norms with ||Y

_{EXP}>|=4.41537, statistic and algebraic correlation factors, computed upon the relations (6), (7), and (8), throughout the possible correlation models considered from the cationic data in Table 2, respectively.

Mode | Vectors | Cationic S-SAR | ||Y_{C}^{Mode}| | ${r}_{S-SAR}^{STATISTIC}$ | ${r}_{S-SAR}^{ALGEBRAIC}$ |
---|---|---|---|---|---|

Ia | | X_{0} 〉, | X_{1}_{C} 〉 | | Y_{C} 〉 ^{Ia} = 0.152926 | X_{0} 〉 −0.124263 | X_{1}_{C} 〉 | 1.47807 | 0.267342 | 0.334755 |

Ib | | X_{0} 〉, | X_{2}_{C} 〉 | | Y_{C} 〉 ^{Ib} =0.0998011 | X_{0} 〉 −0.0129369 | X_{2}_{C} 〉 | 1.08531 | 0.132169 | 0.245803 |

Ic | | X_{0} 〉, | X_{3}_{C} 〉 | | Y_{C} 〉 ^{Ic} = −0.106319 | X_{0} 〉 +2.57881·10^{−7} | X_{3}_{C} 〉 | 0.9452 | 0.0469985 | 0.21407 |

IIa | | X_{0} 〉, | X_{1}_{C} 〉, | X_{2}_{C} 〉 | | Y_{C} 〉 ^{IIa} = −0.195021 | X_{0} 〉 −0.241666 | X_{1}_{C} 〉 +0.0295874 | X_{2}_{C} 〉 | 1.64279 | 0.314715 | 0.372062 |

IIb | | X_{0} 〉, | X_{1}_{C} 〉, | X_{3}_{C} 〉 | | Y_{C} 〉 ^{IIb} = −0.139788 | X_{0} 〉 −0.222688 | X_{1}_{C} 〉 −1.62349·10^{−6} | X_{3}_{C} 〉 | 1.72651 | 0.3379 | 0.391023 |

IIc | | X_{0} 〉, | X_{2}_{C} 〉, | X_{3}_{C} 〉 | | Y_{C} 〉 ^{IIc} = 0.384457 | X_{0} 〉 −0.124625 | X_{2}_{C} 〉 −6.48599·10^{−6} | X_{3}_{C} 〉 | 1.71867 | 0.335748 | 0.389246 |

III | | X_{0} 〉, | X_{1}_{C} 〉, | X_{2}_{C} 〉, | X_{3}_{C}〉 | | Y_{C} 〉 ^{III} = 0.141278 | X_{0} 〉 −0.127251 | X_{1}_{C} 〉 −0.0677301 | X_{2}_{C} 〉 −4.48229·10^{−6} | X_{3}_{C} 〉 | 1.79053 | 0.355322 | 0.405522 |

**Table 4.**Spectral structure activity relationships (S-SAR) of the ionic liquids of Figure 2 against Vibrio fischeri toxicity, and the associated computed spectral norms with ||Y

_{EXP}>|=4.41537, statistic and algebraic correlation factors, computed upon the relations (6), (7), and (8), through all possible correlation models considered from the anionic data in Table 2, respectively.

Mode | Vectors | Anionic S-SAR | ||Y_{A}^{Mode}| | ${r}_{S-SAR}^{STATISTIC}$ | ${r}_{S-SAR}^{ALGEBRAIC}$ |
---|---|---|---|---|---|

Ia | | X_{0} 〉, | X_{1}_{A} 〉 | | Y_{A} 〉 ^{Ia} = −0.514106 | X_{0} 〉 +0.291698 | X_{1}_{A} 〉 | 1.38453 | 0.238974 | 0.313569 |

Ib | | X_{0} 〉, | X_{2}_{A}〉 | | Y_{A} 〉 ^{Ib} = −0.703086 | X_{0} 〉+0.122745 | X_{2}_{A} 〉 | 1.48745 | 0.270118 | 0.33688 |

Ic | | X_{0} 〉, | X_{3}_{A}〉 | | Y_{A} 〉 ^{Ic} = 0.376373 | X_{0} 〉 +5.11098·10^{−7} | X_{3}_{A} 〉 | 1.75453 | 0.345553 | 0.397368 |

IIa | | X_{0} 〉, | X_{1}_{A} 〉, | X_{2}_{A} 〉 | | Y_{A} 〉 ^{IIa} = −0.713422 | X_{0} 〉 +0.131985 | X_{1}_{A} 〉 +0.0904438 | X_{2}_{A} 〉 | 1.52849 | 0.282139 | 0.346174 |

IIb | | X_{0} 〉, | X_{1}_{A} 〉, | X_{3}_{A} 〉 | | Y_{A} 〉 ^{IIb} = 0.055315 | X_{0} 〉 +0.359176 | X_{1}_{A} 〉 +5.73182·10^{−7} | X_{3}_{A} 〉 | 2.15865 | 0.451919 | 0.488893 |

IIc | | X_{0} 〉, |X_{2}_{A} 〉, |X_{3}_{A} 〉 | | Y_{A} 〉 ^{IIc} = 0.0132641 | X_{0} 〉 +0.0618883 | X_{2}_{A} 〉 +4.14933·10^{−7} | X_{3}_{A} 〉 | 1.82903 | 0.365689 | 0.414242 |

III | | X_{0} 〉, | X_{1}_{A} 〉, | X_{2}_{A} 〉, |X_{3}_{A} 〉 | | Y_{A} 〉 ^{III} = 0.912459 | X_{0} 〉 +0.776175 | X_{1}_{A} 〉 −0.209622 | X_{2}_{A} 〉 +9.70982·10^{−7} | X_{3}_{A} 〉 | 2.36461 | 0.504184 | 0.53554 |

**Table 5.**Spectral structure activity relationships (S-SAR) of the ionic liquids of Figure 2 against Vibrio fischeri toxicity, and the associated computed spectral norms with ||Y

_{EXP}>|=4.41537, statistic and algebraic correlation factors, computed upon the relations (6), (7), and (8), through all possible correlation models considered for the cationic-anionic interaction (11), respectively.

Mode | Ionic Liquid S-SAR | ||Y_{AC} 〉 ^{Mode} | ${r}_{S-SAR}^{STATISTIC}$ | ${r}_{S-SAR}^{ALGEBRAIC}$ |
---|---|---|---|---|

Ia | | Y_{AC} 〉 ^{Ia} = −0.36118 | X_{0} 〉 −0.124263 | X_{1}_{C} 〉 +0.291698 | X_{1}_{A} 〉 | 2.58965 | 0.185959 | 0.586507 |

Ib | | Y_{AC} 〉 ^{Ib} = −0.603285 | X_{0} 〉 −0.0129369 | X_{2}_{C} 〉 +0.122745 | X_{2}_{A} 〉 | 2.30825 | 0.179482 | 0.522776 |

Ic | | Y_{AC} 〉 ^{Ic} =0.270054 | X_{0} 〉 +2.57881·10^{−7} | X_{3}_{C} 〉 +5.11098·10^{−7} | X_{3}_{A} 〉 | 2.41575 | 0.259502 | 0.547123 |

IIa | | Y_{AC} 〉 ^{IIa} = −0.908443 | X_{0} 〉 −0.241666 | X_{1}_{C} 〉 +0.131985 | X_{1}_{A} 〉 +0.0295874 | X_{2}_{C} 〉 +0.0904438 | X_{2}_{A} 〉 | 2.88368 | 0.219986 | 0.653101 |

IIb | | Y_{AC} 〉 ^{IIb} = −0.084473 | X_{0} 〉 −0.222688 | X_{1}_{C} 〉 +0.359176 | X_{1}_{A} 〉 −1.62349·10^{−6} | X_{3}_{C} 〉 +5.73182·10^{−7} | X_{3}_{A} 〉 | 3.48056 | 0.352356 | 0.788283 |

IIc | | Y_{AC} 〉 ^{IIc} =0.397721 | X_{0} 〉 −0.124625 | X_{2}_{C} 〉+0.0618883 | X_{2}_{A} 〉 −6.48599·10^{−6} | X_{3}_{C} 〉+4.14933·10^{−7} | X_{3}_{A} 〉 | 3.17318 | 0.299925 | 0.718667 |

III | | Y_{AC} 〉 ^{III} =1.05374 | X_{0} 〉 −0.127251 | X_{1}_{C} 〉 +0.776175 | X_{1}_{A} 〉 −0.0677301 | X_{2}_{C} 〉 −0.209622 | X_{2}_{A} 〉 −4.48229·10^{−6} | X_{3}_{C} 〉 +9.70982·10^{−7} | X_{3}_{A} 〉 | 3.7151 | 0.397148 | 0.841402 |

Mode | Ia | Ib | Ic | IIa | IIb | IIc | III |
---|---|---|---|---|---|---|---|

cosθ_{AC} | 0.66397 | 0.600124 | 0.562018 | 0.653248 | 0.60019 | 0.599635 | 0.591015 |

**Table 7.**Synopsis of the statistic and algebraic values of paths connecting the S-SAR models of Table 5, in the norm-correlation spectral-space of Figure 3, for the ionic liquids of Figure 2 against Vibrio fischeri toxicity. The primary, secondary and tertiary - the so called alpha (α), beta (β) and gamma (γ) paths, are indicated according to the least path principle in spectral norm-correlation space with the statistic and algebraic variants of the correlation factors used, respectively.

Path | Value | |||||
---|---|---|---|---|---|---|

Cationic | Anionic | Ionic Liquid | ||||

statistic | algebraic | statistic | algebraic | statistic | algebraic | |

Ia-IIa-III | 0.324618 | 0.320376α | 1.0154 | 1.0049 | 1.14608 | 1.15396α |

Ia-IIb-III | 0.324616 | 0.320376 | 1.01536γ | 1.0049γ | 1.1451α | 1.15396 |

Ia-IIc-III | 0.324616α | 0.320376 | 1.01541 | 1.0049 | 1.14513 | 1.15396 |

Ib-IIa-III | 0.739827 | 0.723082 | 0.907864β | 0.899373β | 1.42694γ | 1.44248 |

Ib-IIb-III | 0.739746β | 0.723082 | 0.907871 | 0.899373 | 1.42377 | 1.44248γ |

Ib-IIc-III | 0.739754 | 0.723082β | 0.907893 | 0.899373 | 1.42385 | 1.44248 |

Ic-IIa-III | 0.900418γ | 0.86674 | 1.09986 | 1.08906 | 1.31968 | 1.33226 |

Ic-IIb-III | 0.900057 | 0.86674γ | 0.630373 | 0.625533 | 1.30763 | 1.33226 |

Ic-IIc-III | 0.90009 | 0.86674 | 0.630371α | 0.625533α | 1.30908β | 1.33226β |

## Acknowledgements

## References

- Pernak, J.; Chwala, P. Synthesis and Anti-Microbial Activities of Choline-Like Quaternary Ammonium Chlorides. Eur. J. Med. Chem
**2003**, 38, 1035–1042. [Google Scholar] - Bernot, R.J.; Brueseke, M.A.; Evans-White, M.A.; Lamberti, G.A. Acute and Chronic Toxicity of Imidazolium-Based Ionic Liquids on Daphnia Magna. Environ. Toxicol. Chem
**2005**, 24, 87–92. [Google Scholar] - Sheldon, R.A. Green Solvents for Sustainable Organic Synthesis: State of the Art. Green Chem
**2005**, 7, 267–278. [Google Scholar] - Docherty, K.M.; Kulpa, C.F., Jr. Toxicity and Antimicrobial Activity of Imidazolium and Pyridinium Ionic Liquids. Green Chem
**2005**, 7, 185–189. [Google Scholar] - Freemantle, M. New Frontiers for Ionic Liquids. Chem. Eng. News
**2007**, 1, 23–26. [Google Scholar] - Anastas, P.T.; Warner, J.C. Green Chemistry Theory and Practice; 1998; Oxford University Press: New York. [Google Scholar]
- Jastorff, B.; Molter, K.; Behrend, P.; Bottin-Weber, U.; Filser, J.; Heimers, A.; Ondurschka, B.; Ranke, J.; Scaefer, M.; Schroder, H.; Stark, A.; Stepnowski, P.; Stock, F.; Stormann, R.; Stolte, S.; Welz-Biermann, U.; Ziegert, S.; Thoming, J. Progress in Evaluation of Risk Potential of Ionic Liquids—Basis for an Eco-design of Sustainable Products. Green Chem
**2005**, 7, 362–372. [Google Scholar] - Wells, A.S.; Coombe, V.T. On the Freshwater Ecotoxicity and Biodegradation Properties of Some Common Ionic Liquids. Org. Process Res. Dev
**2006**, 10, 794–798. [Google Scholar] - Garcia, M.T.; Gathergood, N.; Scammells, P.J. Biodegradable Ionic Liquids. Part II. Effect of the Anion and Toxicology. Green Chem
**2005**, 7, 9–14. [Google Scholar] - Jain, D.; Kumar, A.; Chauhan, S.; Chauhan, S.M.S. Chemical and Biochemical Transformation in Ionic Liquids. Tetrahedron
**2005**, 61, 1015–1060. [Google Scholar] - Dupont, J.; Suarez, P.A.Z. Physico-Chemical Processes in Imidazolium Ionic Liquids. Phys. Chem. Chem. Phys
**2006**, 8, 2441–2452. [Google Scholar] - Hansen, J.P.; McDonald, I.R. Theory of Simple Liquids1986; Academic Press: London, 2nd Ed ed. [Google Scholar]
- Scammells, P.J.; Scott, J.L.; Singer, R.D. Ionic Liquids: The Neglected Issues. Aust. J. Chem
**2005**, 58, 155–169. [Google Scholar] - Hunt, P.A.; Gould, I.R.; Kirchner, B. The Structure of Imidazolium-Based Ionic Liquids: Insights from Ion-Pair Interactions. Aust. J. Chem
**2007**, 60, 9–14. [Google Scholar] - Hunt, P.A.; Kirchner, B.; Welton, T. Characterizing the Electronic Structure of Ionic Liquids: An Examination of the 1-Butyl-3-ethylimidazolium Chloride Ion Pair. Chem. Eur. J
**2006**, 12, 6762–6775. [Google Scholar] - Hunt, P.A.; Gould, I.R. Structural Characterization of the 1-Butyl-3-Methylimidazolium Chloride Ion Pair Using Ab Initio Methods. J. Phys. Chem. A
**2006**, 110, 2269–2282. [Google Scholar] - Hunt, P.A. The Simulation of Imidazolium-Based Ionic Liquids. Mol. Simul
**2006**, 32, 1–10. [Google Scholar] - Putz, M.V.; Lacrămă, A.-M. Introducing Spectral Structure Activity Relationship (S-SAR) Analysis. Application to Ecotoxicology. Int. J. Mol. Sci
**2007**, 8, 363–391. [Google Scholar] - Jastorff, B.; Stormann, R.; Ranke, J.; Molter, K.; Stock, F.; Oberheitmann, B.; Hoffmann, W.; Hoffmann, J.; Nuchter, M.; Ondruschka, B.; Filser, J. How Hazardous are Ionic Liquids? Structure – Activity Relationship and Biologic Testing as Important Elements for Sustainability Evaluation. Green Chem
**2003**, 5, 136–142. [Google Scholar] - Pernak, J.; Sobaszkiewicz, K.; Mirska, I. Antimicrobial Activities of Ionic Liquids. Green Chem
**2003**, 5, 52–56. [Google Scholar] - Lacrămă, A.M.; Putz, M.V.; Ostafe, V. Designing a Spectral Structure-Activity Ecotoxico-Logistical Battery. Advances in Quantum Chemical Bonding Structures; Putz, M.V., Ed.; Research Signpost: Kerala, India, 2007. in press ( http://www.trnres.com/putz.htm).
- National Toxicology Program (NTP) and National Institute of Environmental Health Sciences (NIEHS), Review of Toxicological Literature for Ionic Liquids; 2004; Prepared By Integrated Laboratory Systems Inc., Research Triangle Park.
- Bernot, R.J.; Kennedy, E.E.; Lamberti, G.A. Effects of Ionic Liquids on the Survival, Movement, and Feeding Behavior of the Freshwater Snail, Physa Acuta. Environ. Toxicol. Chem
**2005**, 24, 1759–1765. [Google Scholar] - Couling, D.J.; Bernot, A.R.; Docherty, K.M.; Dixon, J.K.; Maginn, E.J. Assessing the Factors Responsible for Ionic Liquid Toxicity to Aquatic Organisms via Quantitative Structure – Property Relationship Modeling. Green Chem
**2006**, 8, 82–90. [Google Scholar] - Hypercube, Inc, 2002; HyperChem 7.01, Program package.
- Stepnowski, P.; Skladanowski, A.C.; Ludwiczak, A.; Laczynska, E. Evaluating the Cytotoxicity of Ionic Liquids Using Human Cell Line Hela. Hum. Exp. Toxicol
**2004**, 23, 513–517. [Google Scholar] - Hansch, C.; Leo, A. Exploring QSAR; 1995; ACS Professional Reference Book; ACS: Washington, DC. [Google Scholar]
- Swatloski, R.P.; Holbrey, J.D.; Rogers, R.D. Ionic Liquids Are Not Always Green: Hydrolysis of 1-Butyl-3-Methylimidazolium Hexafluorophosphate. Green Chem
**2003**, 5, 361–363. [Google Scholar] - Kamrin, M.A. Pesticide Profiles: Toxicity, Environmental Impact, and Fate; 1997; Lewis Publishers: Boca Raton, Florida. [Google Scholar]
- Docherty, K.M.; Hebbeler, S.Z.; Kulpa, C.F., Jr. An Assessment of Ionic Liquid Mutagenicity Using the Ames Test. Green Chem
**2006**, 8, 560–567. [Google Scholar] - Stock, F.; Hoffmann, J.; Ranke, J.; Stormann, R.; Ondruschka, B.; Jastorff, B. Effects of Ionic Liquids on the Acetylcholinesterase —A Structure-Activity Relationship Consideration. Green Chem
**2004**, 6, 286–290. [Google Scholar] - Raves, M.L.; Harel, M.; Pang, Y.P.; Silman, I.; Kozikowski, A.P.; Sussman, J.L. 3D Structure of Acetylcholinesterase Complexed with the Nootropic Alkaloid, (−)-Huperzine A. Nat. Struct. Biol
**1997**, 4, 57–63. [Google Scholar] - Skladanowski, A.C.; Stepnowski, P.; Kleszczynski, K.; Dmochowska, B. AMP Deaminase in Vitro Inhibition by Xenobiotics. A Potential Molecular Method for Risk Assessment of Synthetic Nitro- and Polycyclic Musks, Imidazolium Ionic Liquids and N-Glucopyranosyl Ammonium Salts. Environ. Toxicol. Phar
**2005**, 19, 291–296. [Google Scholar] - Ranke, J.; Molter Stock, F.; Bottin-Weber, U.; Poczobutt, J.; Hoffmann, J.; Ondruschka, B.; Filser, J.; Jastorff, B. Biological Effects of Imidazolium Ionic Liquids with Varying Chain Lengths in Acute Vibrio Fischeri and Wst-1 Cell Viability Assays. Ecotoxicol. Environ. Saf
**2004**, 58, 396–404. [Google Scholar] - Standard Test Method for Assessing the Microbial Detoxification of Chemically Contaminated Water and Soil Using a Toxicity Test with a Luminescent Marine Bacterium. In ASTM Designation: D 5660–96; 1996.
- Kaiser, K.L.E.; Palabrica, V.S. Photobacterium phosphoreum Toxicity Data Index. Water Poll. Res. J. Can
**1991**, 26, 361–431. [Google Scholar] - McQueen, D.J.; Post, J.R.; Mills, E.L.; Fish, C.J. Trophic Relationships in Freshwater Pelagic Eco-systems. Can. J. Fish. Aquat. Sci
**1986**, 43, 1571–1581. [Google Scholar] - Swatloski, R.P.; Holbrey, J.D.; Memon, S.B.; Caldwell, G.A.; Caldwell, K.A.; Rogers, R.D. Using Caenorhabditis Elegans to Probe Toxicity Of 1-Alkyl-3-Methylimidazolium Chloride Based Ionic Liquids. Chem. Commun.
**2004**, 668–669. [Google Scholar] - Wong, P.T.; Couture, P. Toxicity Screening Using Phytoplankton. Dutka, B.J., Bitton, G., Eds.; In Toxicity Testing Using Microorganisms; 1986; Volume II, CRC Press: Boca Raton, Fl; pp. 79–100. [Google Scholar]
- Latala, A.; Stepnowski, P.; Nedzi, M.; Mrozik, W. Marine Toxicity Assessment of Imidazolium Ionic Liquids: Acute Effects on the Baltic Algae Oocystis submarina and Cyclotella meneghiniana. Aquat. Toxicol
**2005**, 73, 91–98. [Google Scholar] - EN Water Quality—Fresh Water Algal Growth-Inhibition Test with Scenedesmus Subspicatus and Selenastrum Capricornutum (ISO 8692: 1993). In European Committee for Standardization; 1993; Brussels.
- EN Water Quality—Marine Algal Growth-Inhibition Test with Skeletonema Costatum and Phaeodactylum Tricornutum (Iso 10253:1995). In European Committee for Standardization; 1995; Brussels.
- Cross, J. Introduction to Cationic Surfactants: Analytical and Biological Evaluation1994; Marcel Dekker, Inc: New York, 3rd Ed ed. [Google Scholar]
- Pretti, C.; Chappe, C.; Pieraccini, D.; Gregori, M.; Abramo, F.; Monni, G.; Intorre, L. Acute Toxicity of Ionic Liquids to The Zebrafish (Danio rerio). Green Chem
**2006**, 8, 238–240. [Google Scholar] - Newman, M.; Dixon, P. Ecologically Meaningful Estimates of Lethal Effect in Individuals. In Ecotoxicology: A Hierarchical Treatment; Newman, Mc, Jagoe, Ch., Eds.; Lewis: Boca Raton, U.S.A, 1996; pp. 225–253. [Google Scholar]
- Gathergood, N.; Garcia, M.T.; Scammells, P.J. Biodegradable Ionic Liquids: Part I. Concept, preliminary targets and evaluation. Green Chem
**2004**, 6, 166–175. [Google Scholar] - Gathergood, N.; Scammells, P.J.; Garcia, M.T. Biodegradable Ionic Liquids. Part III. The First Readily Biodegradable Ionic Liquids. Green Chem
**2006**, 8, 156–160. [Google Scholar] - Ropel, R.; Belveze, L.S.; Aki, S.N.V.K.; Stadtherr, M.A.; Brennecke, J.F. Octanol-Water Partition Coefficients of Imidazolium-Based Ionic Liquids. Green Chem
**2005**, 7, 83–90. [Google Scholar] - Stolte, S.; Arning, J.; Bottin-Weber, U.; Matzke, M.; Stock, F.; Thiele, K.; Uerdingen, M.; Welz-Biermann, U.; Jastorff, B.; Ranke, J. Anion Effects on the Cytotoxicity of Ionic Liquids. Green Chem
**2006**, 8, 621–629. [Google Scholar] - Shugart, L. Molecular Markers to Toxic Agents. In Ecotoxicology: A Hierarchical Treatment; Newman, Mc, Jagoe, Ch., Eds.; Lewis: Boca Raton, Fl, 1996; pp. 133–161. [Google Scholar]
- Stiefl, N.; Bauman, K. Structure-Based Validation of the 3D-QSAR Technique MaP. J. Chem. Inf. Mod
**2005**, 45, 739–749. [Google Scholar]

© 2007 by MDPI Reproduction is permitted for noncommercial purposes.

## Share and Cite

**MDPI and ACS Style**

Lacrămă, A.-M.; Putz, M.V.; Ostafe, V.
A Spectral-SAR Model for the Anionic-Cationic Interaction in Ionic Liquids: Application to Vibrio fischeri Ecotoxicity. *Int. J. Mol. Sci.* **2007**, *8*, 842-863.
https://doi.org/10.3390/i8080842

**AMA Style**

Lacrămă A-M, Putz MV, Ostafe V.
A Spectral-SAR Model for the Anionic-Cationic Interaction in Ionic Liquids: Application to Vibrio fischeri Ecotoxicity. *International Journal of Molecular Sciences*. 2007; 8(8):842-863.
https://doi.org/10.3390/i8080842

**Chicago/Turabian Style**

Lacrămă, Ana-Maria, Mihai V. Putz, and Vasile Ostafe.
2007. "A Spectral-SAR Model for the Anionic-Cationic Interaction in Ionic Liquids: Application to Vibrio fischeri Ecotoxicity" *International Journal of Molecular Sciences* 8, no. 8: 842-863.
https://doi.org/10.3390/i8080842