IBN AL- HAITHAM J. FOR PURE & APPL. S CI. VOL.23 (2) 2010 Synthesis and Spectral Studies for new Schiff base and its Binuclear Complexes with ZnII,CdII and HgII A.T. Numan Departme nt of Chemistry, College of Education, I bn Al Haitham, Unive rsity of Baghdad Abstract A new ligand (H4L) and its comp lexes with ( Zn II , Cd II and Hg II ) were p repared. This ligand was p repared in two st eps. In t he first st ep a solution of terep hthaldehyde in methanol was reacted under reflux with 1,2-p henylenediamine to give an p recursor comp ound which reacted in the second st ep with 2,4-dihydroxy benzaldehy de to give the ligand. The comp lexes were then sy nthesized by direct reaction of the corresp onding metal chloride with the ligand. The ligand and comp lexes were characterized by sp ectroscop ic methods FT -IR, UV-Vis, 1 HNM R, and atomic absorp tion, chloride content, HPLC, mole-ratio determination. in addition to conductivity measurement. T he data of these measurements suggest a distorted tetrahedral geometry for Zn II , Cd II and Hg II comp lexes and that they would be p resented as [M 2L(H2L)CI2]. The Stability Const ant K and Gibbs free energy ∆G were calculated for [Zn2(H2L)Cl2] and [Cd2(H2L)Cl2] comp lexes by using sp ectrop hotometer method. The obtained values indicate that these comp lexes are st able in their solution. The biological activity for the following ligand ( H4L ) and comp lexes [Zn2(H2L)Cl2] and [Cd2(H2L)Cl2] was studied . Introduction Schiff's bases derived from aromatic amines and aromatic aldehydes and its comp lexes have a wide variety of app lications in many fields, e.g., biological, inorganic and analytical chemist ry [1-3]. Schiff's bases of o-p henylenediamine and its comp lexes have a variety of app lications including biological, analytical [4] and clinical [5]. M etal comp lexes of Schiff base are extensively st udied due to sy nthetic flexibility and sensitivity toward a variety of metal atoms [6].They are found useful in cataly sis, in medicine as antibiotics and anti-inflammatory agent and in the industry as anti-corrosion [7-10]. It has been found that all the comp lexes are antimicrobially active and show higher activity than the free ligand. M etal chelation affects significantly the antimicrobial/bioactive behavior of the organic ligands [11].In this p aper the sy nthesis and characterization of Schiff base [4,4'–(2,2'-(1,4-phenelenebis(methan-1-y l-1- y lidene))bis(azan-1-y l-1-ylidene)bis(1,2-p henylen))bis(azan-1-l-1-ylidene)bis(methan-1-yl-1- y lidene)dibenzene1,3-diol] ligand derived from the reaction of terep hthaldehyde, o- p henylenediamine and 2,4 -Dihy droxy benzaldehy de and some of its comp lexes with ( Zn II , Cd II and Hg II ) are reported. Experime ntal Reagent gr ade terep hthaldehyde and 2,4 -Dihy droxy benzaldehy de obtained from Fluka and o-p heny lenediamine obtained from aldrich and used as received while ZnCl2 , CdCl2.H2O and HgCl2 wer e available from (Ried ial – Dehaen, Fluka, M erck and Hop kins & William LTD) resp ectively. The FT-IR sp ectra of comp ounds were recorded as (KBr) disc using a shimadzu 8300 FT IR Sp ectrop hotometer in the range (4000-400) cm -1 . Electronic sp ectra of prep ared IHJPAS IBN AL- HAITHAM J. FOR PURE & APPL. S CI. VOL.23 (2) 2010 comp ounds were measured in the region (200-900) nm for 10 -3 M solutions in (DM F) as a solvent at 25 C˚ by using a CECIL, CE7200 sp ectrop hotometer. While metal contents of the comp lexes were determined by atomic absorp tion (A.A) technique using a shimadz (AA.620) atomic absorption sp ectrop hotometer .Electrical conductivity measurements of the comp lexes were recorded at 25 C˚ for 10 -3 M solutions of the samples in (DM F) by using a ( Wissenschaftlich- Techniche Werkst att en. D1820 Wilhelm LF 42) conductivity meter. Nuclear magn etic resonance sp ectra 1 HNM R for the ligand (H4L) were recorded Via usin g Burker (400M Hz) sp ectrop hotometer with a tetramethy lsilane (TM S) as an internal st andard in DM SO-d 6 in Al- Baath University , Sy ria. The chloride contents for comp lexes were determin ed by p otentiometric titration method on (686-Titro p rocessor-665. Dosimat M etrohn Swiss).The melting p oint was measured using Stuart melting p oint. Preparation S ynthesis of the ligand (H4L): The li gand was p repared in two step s S tep (1): preparation of the (precursor compound). To a solution of terep hthaldehyde 0.15 g ( 1.12 mmole) in (5 ml) of methanol, (5) drop s of glacial acetic acid were slowly added, the obtained solution was mixed with 1,2- p heny lenediamine 0.241 g (2.23 mmole) (5ml) in methanol. The mixture was reflu xed for (5 hrs.) with stirring. The oran ge solution was left t o dry for (24 hrs.) in room temp erature, the p recipitate was washed with an excess of methanol, and was dried. An orange solid was obtained. Yield (0.26) g, (74%), m.p (190 dec). S tep (2): preparation of the ligand (H4L): A solution of (p recursor comp ound) 0.12 g ( 0.38 mmole) in methanol (5 ml) and few drop s of DMF were added to 0.1 g ( 0.72 mmo le) of 2,4-dihydroxy benzaldehy de dissolving in methanol (5ml), then five drops of glacial acetic acid were added slowly to the reaction mixture. The reaction mixture was refluxed for (5 hrs.) with continuous stirring. The brown solution was left to dry for (72 hrs.) at room temp erature, the p recipitate was washed with an excess of methanol, and was dried. A brown solid was obtained. Yield (0.18) g, (85%), m.p (223 dec) . S ynthesis of complexes ions S ynthesis of [Zn2(H2L)Cl 2] (1) complex: 5ml of methanol it solution containing 0.15 g (0.27 mmole) of (H4L) with few drop s of DM F were p laced in a round bottomed flask. Then a 0.04g (0.71 mmol) of KOH in (5 ml) ethanol was added. A solution of ZnCl2 0.074g (0.54 mmole) in (10 ml) methanol was drop wise added with st irring. The mixture was refluxed for (3 hrs.). A deep green p recipitate was formed, which was filtered off, washed several times with methanol and dried at room temperature during (72 hrs.). Yield (0.051) g, (76 %), m.p. (270 dec). S ynthesis of [Cd2(H2L)Cl 2] (2), [Hg2(H2L)Cl 2] (3) The method used to p rep are these comp lexes was a similar method to that mentioned in the prep aration of [Zn2(H2L)Cl2] comp lex. Table (1) shows t he stated weight of st arting materials, % y ield and some p hysical p rop erties of the prep ared comp lexes. Results and Discussion The prep aration of the ligand (H4L) and comp lexes of the general method as shown in Scheme IHJPAS IBN AL- HAITHAM J. FOR PURE & APPL. S CI. VOL.23 (2) 2010 (1) O O H2N NH2 N N NH2H2N (1 mole) (2 mole) OH OH CH O N N N N HC CHCH HC OHHO OH HO MeO H \ DMF HC OHHO O M Cl Cl N N N N HC CHCH O M Me OH terep hthalaldehy de 1,2p he nylene diam ine glac ia lac eti c acid (5 dr op s) refl ux (1 5 hrs .) Me OH \ DM F 2 ,4-di hydroxy benza lde hyde (2mo le ) r efl ux (15 hr s.) gl acial aceti c acid 5 drop s 2M C l2 + 2 KO H reflux ( 3h rs.) [w here M (II)=Zn,C d a nd Hg ] Scheme (1) Synthesis route of the Schiff's base ligand (H4L) and its complexes IHJPAS IBN AL- HAITHAM J. FOR PURE & APPL. S CI. VOL.23 (2) 2010 The 1 HNM R sp ectrum of ligand (H4L), Figure (2) in DM SO–d 6 solvent shows a singlet signal at ( = 10.93 p p m) equivalent to two p rotons assigned to (O–H) group of carbon (C1,32). Two p rotons of (C5-OH, C30-OH) group app ear as a singlet signal at ( = 13.1 p p m) [18]. Two p rotons of (N=C7–H, N=C28–H) imine group app ear as a singlet signal at ( = 8.36 p p m). Two p rotons of (N=C14–H, N=C21–H) imine group app ear as a singlet signal at ( = 9.93 p p m). The multiplet signals at ( = 6.33 p p m), (7.23), (7.33), (7.46), (7.53), (7.63), (7.95) p p m are due to aromatic hy drogen of carbon (C2,33), (C3,34), (C6,31), (C9,12,23,26), (C10,11,24,25), (C16,17), (C19,20) resp ectively[13,14]. The FTIR sp ectra of the ligand and the comp lexes are p resented in table (2) and fig (3a,3b). The sp ectrum of the ligand fig (3a) shows the disapp earance of C=O and N-H bands, which sup p ose the comp lete condition of keto group with amino group [15,16]. So the st rong band app eared at 1635 cm -1 and 1620 cm -1 can be att ributed to imin group C=N (benz) and (tere) resp ectively while the band at 1238 cm -1 can be assigned to C-O. T he two bands at 3429 cm -1 and 3140 cm -1 are due to the υ (O-H) st retching [17,18]. In the case of the comp lexes (1-3) fig (3b) the bands of C=N and C-O shifted to lower frequency app earing for C=N at (1627,1604) cm -1 ,( 1620 , 1589) cm -1 , (1600, 1577) cm -1 and at (1215, 1203, 1226) cm -1 for (C-O)[19-22]. The shifting which may be due to (HOM O →LUM O), (where HOM O: Highest Occupied M olecular Orbital, LUM O: Lowest Unoccupied M olecular Orbital) confirmed the coordination of ligand through nitrogen and oxy gen atoms [23]. The broad band at (3429) cm -1 att ributed to υ(OH) in the free ligand shifted to lower frequency app eared at (3329) cm -1 , (3387) cm -1 and (3356) cm -1 for comp lexes [1-3] resp ectively[24]. The bands at (550), (551) and (559) were assigned to υ (M – N) for comp ounds [1-3] resp ectively, indicating that the imine nitrogen is involved in coordination with metal ions [25, 26]. The bands at (421), (470) and (497) cm -1 were assigned to υ(M –O) for comp ounds (1-3) resp ectively indicating that the p henolic oxy gen of the ligand is involved in coordination with metal ions[25,26]. The (UV-Vis) sp ectrum for the ligand (H4L), Figure (4) exhibits three high absorp tion p eak, the first p eaks, at (282nm) (35460.99 cm -1 ) (εm ax=2229molar -1 .cm -1 ), the second absorp tion p eak at (330nm)(30303 cm -1 ) (εmax=2175 molar -1 .cm -1 ) and the third p eak at (348nm)(28571.4 cm - 1 )(εm ax= 1861molar -1 . cm -1 ), which were assigned to (π→ π*) , (π→ π*) and (n→ π*) transition resp ectively[17]. The (UV-Vis) sp ectra data for the comp lexes (1-3) are given in table (3).The absorp tion sp ectra for these comp lexes show intense bands about (291-345) nm , which may be related to ligand filed. The absorp tion p eaks in the range (351-360) nm for these comp lexes are due to charge transfer (C.T) since they belong to d 10 configuration and they don’t have d-d transition [27,28]. From the p osition of the band and the value of εm ax the tetrahedral st ructure may be p rop osed for these complexes. The M olar conductance values for the ligand (H4L) comp lexes are summarized in table (3). These values were found in the range (24.9 - 27.9) S.cm 2 .mole -1 , so they corresp ond to non- electrolytic behavior [29]. The (HPLC) chromatograms for the comp ound (H4L), [Zn2(H2L)Cl2] and [Cd2(H2L)Cl2] comp lexes, exhibits one sharp signal at retention time (Rt=6.877), (Rt=7.036) and (Rt=7.048) resp ectively, indicating the purity of the compounds . The atomic absorp tion analysis and the chloride content results of the comp lexes are in a good agreement with the suggested formula [M 2(H2L)Cl2]. The mole-ratio (L:M ) was calculated depending on the measurement the absorbance of the solutions which contain increased molar concentrations of one component (ligand) with constant concentration to the other comp onent metal ion. The optical absorbance was measured at wave length of highest absorbance of p roduced comp lex and does not occur at the absorbance to the chelate ligand alone or to the metal ion alone. The relationship between the absorbance which IHJPAS IBN AL- HAITHAM J. FOR PURE & APPL. S CI. VOL.23 (2) 2010 was p resented as (Y) axis and the concentration of the two reactants (ligand: metal) was drawn, which was p resented as (X) axis, then the rectum contiguity was drown until they intersect and from the intersection p oint equivalent metal was limitated as it was shown in the figures (5a) and (5b). On the basis of these measurement the st ability constant K and Gibbs free energy ∆G were calculated. The st ability constant K and Gibbs free energy were calculated using the method shown above. The equilibrium of the comp lex metal ion and the ligand for 2:1 mole ratios and K for this ratio is exp ressed by : 2M+ L M2L …………... (1) K= [M 2L] / [M ] 2 [L] ……………. (2) K= (1- α)/ 4α 3 C 2 …………… (3) Where C and α are the concentration and degree of decomp osition of the comp lex resp ectively, the values were determin ed from the equation α = (Am - AS) / Am As = The absorbance for M :L= 1:2. Am = The absorbance for M :L= 1:3. As and Am, are the absorbance of the M : L =1:1, M : L=2:1, M : L=3:1 and M: L=4:1 resp ectively. The calculation of ∆G at 300°K was carried out according to followin g exp ression ∆G = - 2.303RT log k Where R=8.31J mole - 1 .K -1 and T=300°K. The obtained date is list ed in table (4) which shows t hat the complexes are stable (∆G < 0) and there stability increase in the order Cd (II) > Zn (II). The biological activity of the ligands (H4L) and [Zn2(H2L)Cl2], [Cd2(H2L)Cl2], comp lexes was st udied by using inhib ition method for two typ es of p athogenic bacteria. One ty p e of bacteria was gram positive which is Bacillus Cereus. T he second one was gram n egative which is Pseudomonas. The biological effect of the chemical co mplexes, was studied for the (2) typ es of bacteria as shown in table (5). The rate of inhibition diameter was varied accordin g to the variation in the comp lex ty p e and Bacterial typ e. Re ferences 1. Cimerman, Z.; M iljanic, S. and Galic, N. (2000), Croatica Chemica Acta., 73 (1), 81- 95 2. Singh P, Goel R L, and Singh B P, (1975) J. Indian Chem. Soc., 52, 958. 3. Perry , B.; Beezer, A. E.; M iles, R. J.; Smith, B. W.;, M iller, J. and Nascimento, M . G., (1988) M icrobois., 45, 181. 4. Patel, P. R.; Thaker, B. T. and Zele. S., (1999) Indian J. Chem., 38 A, 563. 5. M ahindra, A. M .; Fisher, J. M .and Rabinovitz, (1983) Nature (London) 303 64. 6. Sp inu, C .and Kriza, A. (2000) Acta Chime. Slov., 47,179. 7. Sun, B.;Chen, J.;Hu ,J. Y. and Li, X. (2001), J Chin.Chem.Lett .,12 (11),1043. 8. Boghaei D M and M ohebi S, (2002) Tetrahedron,58 (26), 5356.. 9. Liu,J.;Wu, B.;Zhang ,B. and Liu, Y. (2006) Turk J.Chem., 30,41. 3), 677.( 358. Inorg. Chim.ActaD, J )2005( ,and Ranford .I .S ,Tan.;X .V ,Jin10. 11. M ishra ,A. P. and M onika Soni, (2008) M et Based Drugs,. 12. Ahsen ,V.; Gök celi, F. and Bekaroğlu, ö. (1987) J. Chem. Soc. Dalton T rans., 1827. 13. Parikh, V. M . (1985) “Absorp tion Sp ectroscop y of Organic M olecules” Translated by Khut hier Abdul Hussain, Al-Rawi Jasim M . A. and Al-Iraqi. M ahammed A. IHJPAS IBN AL- HAITHAM J. FOR PURE & APPL. S CI. VOL.23 (2) 2010 14. Robert, M . Silver Schtein, Bassler and M orrill, (1981) “Sp ectrop hotometer Identification of Organic Compound”, 5yh ed. 15. Sanmartim, J.; Bermejo, M . R. ; Garcia Deibe ,A.M . and Rivas, I.M ., (2000) J. Chem. Soc. Dalton Trans., 4174 - 4181. 16. Aldulaimi, Sultan J. S., (2005) M sc. Thesis, University of Baghdad, College of Education - Ibn- AL-Haitham,. 17. William Kemp, (1987) “Organic Sp ectroscop y ” 2nd Edition. 18. Koksal, H.; Tumer, M . and Serin, S., (1996) Sy nth. Read. Inorg. M et. Org. Chem., 26, 1577. 19. Xishi Tai, Xianhong Yin, Qiang chen, and M inyu Tan, (2003) M olecules, 439-440. 20. Agrawal, R. K.; Prasad, S. and Gahlot, N.. (2004) T wk. J. Chem. 28. 21. Al-Janabi, A. E., (2005) M Sc Thesis, University of Baghdad,. 22. Smith, P.H.; M orris, J.R. and Ry an, G.D., (1989) J. Am.Chem.Soc., 111, 7437. 23. Tumer, M .; Celik, C.; Koksal, H. and Serin, S., (1999) Trans. M et.Chem., 24, 525. 24. Tumer, M .; Koksal, H.; Serin, S. and Digrak, M ., (1999) Trans. M et. Chem., 24, 13. 25. Addison, A.W.; Rao, T.N. and Sinn, E., (1984) Inorg. Chem., 23, 1957-1967. 26. Preti, C. and Tosi, G., (1977) Can J.Chem., 55, 1409. 27. Lever, A. B. P., (1968) “ Inorganic Electronic Sp ectroscop y ”, New York, 6, 121. 28. Karabocek, S. and Kaeabocek, N., (1997) Polyhedron, 11, 1771-1774. 29. Ketlle, S. F. A., (1975) "Coordination Comp ounds", T homas Nelson & Sons, London,. Table (1) Elemental analysis results and some physical propertie s of the complexes and their reactants quantities. Dec=decomposition, calc. = calculated, ( ) =t heoretical No. Empirical Formula colour m.p ºC Wt of metal chlo ride (g ) Wt. of product (g) Yield % Found (cal c.)% metal Cl 1 H4L brown 22 3 dec - 0.18 85 - - 2 [Zn2( H2L)Cl2] P ale yellow 27 0 dec 0.074 0.051 68.91 (17.34) 16.35 (9.4) 8.5 3 [Cd2( H2L)Cl2] P ale yellow 24 0 dec 0.109 0.078 72 (26.50) 25.45 (8.36 ) 7.4 4 [Hg2( H2L )Cl2] P ale yellow 25 0 dec 0.146 0.046 32 (39.15) 37.86 (6.92 ) 5.1 IHJPAS IBN AL- HAITHAM J. FOR PURE & APPL. S CI. VOL.23 (2) 2010 Table (2): FT-IR spectral data (wave number ύ) cm -1 for the ligand (H4L) and its complexes Table (3): Electronic data and molar conductivity for the ligand (H4L) and its Metal complexes υ (M-O) υ (M-N) υ (C-O) υ (C-H) al iph. υ (C-H) arom. υ(C=C) arom. υ (O-H) υ(C=N) Compounds No. - - 12 35 29 27 30 62 1500 3429 1635 1620 [H4L] 421 55 0 12 15 29 24 30 66 1527 3329 1627 1604 [Zn2(H 2L)Cl2] 1 470 55 1 12 03 29 24 29 50 1539 3387 1620 1589 [Cd2(H2L)Cl2] 2 497 55 9 12 22 29 58 30 89 1550 3356 1600 1577 [Hg2(H2L)Cl2] 3 Coordination m  S. cm2. mole –1 Assignments ύ cm -1 λ nm Compou nd s No. _____ π → π * 35460.99 282 H4L π →π * 30303 330 n→ π * 28735.63 348 Distorted T etrahedral Ligand field 34246.57 292 [Zn2(H2L)Cl2] 1 25 Ligand field 29940 334 C.T 28490 351 Distorted T etrahedral Ligand field 34364.689 291 [Cd2(H2L)Cl2] 2 24.9 Ligand field 28985.5 345 C.T 27777.7 360 Distorted T etrahedral Ligand field 34246.57 292 [Hg2(H2L)Cl2] 3 27.9 Ligand field 29850.74 335 C.T 28490 351 IHJPAS IBN AL- HAITHAM J. FOR PURE & APPL. S CI. VOL.23 (2) 2010 Table (4) Stability constant and ∆G for the ligand (H4L) complexes [Zn2(H2L)Cl2] and [Cd2(H2L)Cl2] Compou nd s As Am α K Log K 1/K ∆G [Zn2(H4L)Cl2] 2.37 2.4 0.0125 1.26408090117× 10 11 11 7.91×10 -12 -62.8 [Cd2(H4L)Cl2] 1.82 1.83 0.00546 1.527711213517×10 12 12.18 6.55×10 -13 -69.5 Table (5) Showed the inhibition circle diameter in millimeter for the bacteria after 24 hour incubation paid and 37C for H4L and some complexes Compounds P.S . B.C. Control DM F 10.9 9.9 H4L 30 25 [Zn2(H2L)Cl2] 16 20 [Cd2(H2L)Cl2] 20 18 IHJPAS IBN AL- HAITHAM J. FOR PURE & APPL. S CI. VOL.23 (2) 2010 Fig. (2) 1 HNMR spectrum of the ligand (H4L) Fig. (3a) FT-IR s pectrum for the (H4L) Fig .(3b) FT-IR S pectrum of the complex [(Zn2 (H2L)Cl 2] Fig. (4) Electroni c spectrum of the ligand (H4L) IHJPAS IBN AL- HAITHAM J. FOR PURE & APPL. S CI. VOL.23 (2) 2010 Fig. (5a) The mole-ratio curve of complex [Zn2(H2L)Cl 2] in solution (1× 10 -3 mole.L -1 ) at (λ=345 nm) Fig. (5b) The mole-ratio curve of complex [Cd2(H2L)Cl 2] in soluti on (1× 10 -3 mole.L -1 ) at (λ=335 nm) IHJPAS 2010) 2( 32المجلد مجلة ابن الهیثم للعلوم الصرفة والتطبیقیة حضیر ودراسات طیفیة لقاعدة شف جدیدة ومعقداتها ثنائیة النواة مع ت ZnII, CdII and HgII أحمد ثابت نعمان قسم الكیمیاء، كلیة التربیة ابن الهیثم، جامعة بغداد الخالصة دند الجدیاتضمن البحث تحضیر اللیك 4,4'–(2,2'-(1,4-phenelenebis(methan-1-y l-1-ylidene))bis(azan-1-y l-1-ylidene)bis(1,2- p henylen))bis(azan-1-y l-1-ylidene)bis(methan-1-yl-1-ylidene)dibenzene1,3-diol :إذ حضر هذا اللیكاند بخطوتین terep) (ةفاعلمالخطوة األولى hthaldehyde 1,2 ) مع-p henylenediamine) و تكوین N 1 ,N 1 '-(1,4-phenylenebis(methan-1-y lylidene))dibenzene-1,2diamine ــــة ــــم الخطـــــوة الثانیــ N ةفاعلــ 1 ,N 1 '-(1,4-phenylenebis(methan-1-y lylidene))dibenzene-1,2diamine ـــــع مـ 2,4dihydroxy benzaldehy de ).H4L( الجدید اللیكاندو تكوین 4,4'–(2,2'-(1,4-phenelenebis(methan-1-y l-1-ylidene))bis(azan-1-y l-1-ylidene)bis(1,2- p henylen))bis(azan-1-y l-1-ylidene)bis(methan-1-yl-1-ylidene)dibenzene1,3-diol تكونت معقدات جدیـدة لهـا اذ) 2:1(المیثانول وسطا للتفاعل وبنسبة عمالتم مفاعلة هذا اللیكاند مع بعض العناصر الفلزیة باست M]الصیغة العامة 2(H2L)Cl2] Zn : اذ II , Cd II and Hg II =M (HPLC), ،المرئیـة –األشعة تحت الحمـراء ، واألشـعة فـوق البنفسـجیة ، ق الطیفیةائیع المركبات بالطر جم شخصت , 1 HNM R مـع قیـاس التوصـیلیة الموالریـة ، مطیافیة االمتصاص الذري للعناصر وتم تعیین محتوى الكلور ودرجـات االنصـهار فــانمـن نتـائج البحـث .1:2 للیكانـد الـى الفلـز وكانـت النسـبةلتعیـین نســبة ا) mole-ratio( طریقـة كـذلك اسـتخدمت .الكهربائیـة ) K (ب ثابـت االســتقراریةحســ .المشـوه الســطوح ربـاعي وهــ الزنـك والكــادمیوم والزئبـق كـل مــن الشـكل الفراغــي المقتـرح لمعقــدات .لوجیة للیكاند المحضر ومعقداتهو الفعالیة البای أختیرت . ∆ G وطاقة جبس الحرة IHJPAS IHJPAS