تهجين

‫م‪.‬ﺣﻮراء ﻣﻬﺪي‬ ‫اﻟﻤﺮﺣﻠﺔ اﻟﺜﺎﻟﺜﺔ‬ ‫ﻣﺤﺎﺿﺮات اﻟﻜﻴﻤﻴﺎء اﻟﺘﻨﺎﺳﻘﻴﺔ‬

‫• ﺗﺷﺎﺑﻪ ﺍﻟﺗﻧﺎﺳﻕ‪Coordination isomerism - :‬‬
‫‪ ‬ﻋﻧﺩﻣﺎ ﻳﻛﻭﻥ ﻛﻝ ﻣﻥ ﺍﻷﻳﻭﻥ ﺍﻟﺳﺎﻟﺏ ﻭ ﺍﻟﻣﻭﺟﺏ ﻓﻲ ﻣﺭﻛﺏ ﺃﻳﻭﻧﻲ ﺃﻳﻭﻧﺎ ﻣﻌﻘﺩﺍ‪ ،‬ﻳﻣﻛﻥ ﻷﻱ ﻟﻳﻛﺎﻧﺩ ﺃﻥ‬
‫ﻳﺭﺗﺑﻁ ﺑﺫﺭﺓ ﺍﻟﻔﻠﺯ ﻓﻲ ﺍﻷﻳﻭﻥ ﺍﻟﺳﺎﻟﺏ ﺃﻭ ﻓﻲ ﺍﻷﻳﻭﻥ ﺍﻟﻣﻭﺟﺏ‪ ،‬ﻭ ﺑﺫﻟﻙ ﺗﻭﺟﺩ ﻟﻠﻣﺭﻛﺏ ﺫﻱ ﺍﻟﺻﻳﻐﺔ‬

‫ﺍﻟﻭﺍﺣﺩﺓ ﻋﺩﺓ ﺍﺣﺗﻣﺎﻻﺕ ﻳﻁﻠﻕ ﻋﻠﻳﻬﺎ ﺃﺷﺑﺎﻩ ﺍﻟﺗﻧﺎﺳﻕ‪ ،‬ﻣﺛﺎﻝ‪:‬‬
‫‪[Cr(NH3)6] [Co(C2O4)3] ، [Co(NH3)6] [Cr(C2O4)3] ‬‬

‫• ﺍﻟﺗﺷﺎﺑﻪ ﺍﻟﺑﺻﺭﻱ‪optical isomerism :‬‬
‫‪ ‬ﺍﻛﺗﺷﻔﺕ ﻅﺎﻫﺭﺓ ﺍﻟﺗﺷﺎﺑﻪ ﺍﻟﺑﺻﺭﻱ ﻷﻭﻝ ﻣﺭﺓ ﻓﻲ ﺍﻟﻣﺭﻛﺑﺎﺕ ﺍﻟﻌﺿﻭﻳﺔ ﻋﻧﺩﻣﺎ ﺗﻛﻭﻥ ﺫﺭﺓ ﺍﻟﻛﺭﺑﻭﻥ‬

‫ﻣﺭﺗﺑﻁﺔ ﺑﺄﺭﺑﻊ ﻣﺟﺎﻣﻳﻊ ﻣﺧﺗﻠﻔﺔ‪.‬‬

‫ﻭ ﺛﺑﺕ ﺗﻭﺍﺟﺩﻩ ﻓﻲ ﺍﻟﺟﺯﻳﺋﺎﺕ ﺍﻟﻼﻋﺿﻭﻳﺔ ﺃﻳﺿﺎ‪ .‬ﻭ ﻳﻅﻬﺭ ﻓﻲ ﺣﺎﻟﺔ ﻋﺩﻡ ﺗﻣﺎﺛﻝ ﺍﻟﺟﺯﻱء‪ ،‬ﻓﺈﻧﻪ ﻻ ﻳﻣﻛﻥ ﺗﻁﺎﺑﻘﻪ ﻋﻠﻰ‬
‫ﺻﻭﺭﺗﻪ ﻓﻲ ﺍﻟﻣﺭﺁﺓ‪ ،‬ﻧﻅﺭﺍ ﻟﻌﺩﻡ ﺍﺣﺗﻭﺍﺋﻪ ﻋﻠﻰ ﻣﺭﻛﺯ ﺗﻣﺎﺛﻝ ﻭ ﻟﻳﺱ ﻟﻪ ﻣﺳﺗﻭﻯ ﺃﻭ ﻣﺣﻭﺭ ﺗﻣﺎﺛﻝ‪ .‬ﻓﺎﻟﺷﺑﻳﻬﺎﻥ ﺍﻟﺑﺻﺭﻳﺎﻥ‬
‫ﻳﺧﺗﻠﻔﻭﺍ ﻓﻲ ﺍﻟﺧﻭﺍﺹ ﺍﻟﻔﻳﺯﻳﺎﺋﻳﺔ ﻭ ﻓﻲ ﺍﻷﻁﻳﺎﻑ ﻓﻘﻁ‪ .‬ﻭ ﺗﺳﻣﻰ ﺍﻟﺻﻭﺭﺗﺎﻥ ﻭ ﺍﻟﻠﺗﺎﻥ ﻟﻬﻣﺎ ﺍﻟﺗﻣﺎﺛﻝ ﻧﻔﺳﻪ ﺍﻟﺫﻱ ﻳﻅﻬﺭ‬

‫ﺑﻭﺍﺳﻁﺔ ﺍﻟﻳﺩ ﺍﻟﻳﻣﻧﻰ ﻭ ﺍﻟﻳﺳﺭﻯ ﺑﺯﻭﺝ ﺍﻳﻧﺎﻧﺗﻭﻣﻭﺭﻭﻓﻲ ‪ Enantimorphic‬ﻭ ﺍﻟﺻﻭﺭﺗﺎﻥ ﻣﺗﺷﺎﻛﻠﺗﺎﻥ ﺿﻭﺋﻳﺗﺎﻥ‪.‬‬

‫ﻭ ﻫﻭ ﻋﺑﺎﺭﺓ ﻋﻥ ﺟﺯﻳﺋﻳﺗﻳﻥ ﺃﺣﺩﺍﻫﻣﺎ ﺻﻭﺭﺓ ﻣﺭﺁﺓ ﻟﻠﺛﺎﻧﻳﺔ ﻭ ﻻ ﺗﻧﻁﺑﻕ ﺍﻟﻭﺍﺣﺩﺓ ﻋﻠﻰ ﺍﻷﺧﺭﻯ‪ .‬ﻭ ﻧﻅﺭﺍ ﻟﻌﺩﻡ ﺗﻁﺎﺑﻘﻬﻣﺎ‬
‫ﻓﻬﻣﺎ ﻏﻳﺭ ﻣﺗﻣﺎﺛﻠﺗﻳﻥ ﺭﻏﻡ ﻛﻭﻥ ﺃﻁﻭﺍﻝ ﺟﻣﻳﻊ ﺍﻟﺭﻭﺍﺑﻁ ﻭ ﻣﻘﺎﺩﻳﺭ ﺟﻣﻳﻊ ﺍﻟﺯﻭﺍﻳﺎ ﻓﻲ ﺃﺣﺩﻫﻣﺎ ﻣﻁﺎﺑﻘﺎ ﻟﻣﺎ ﻓﻲ ﺍﻟﺛﺎﻧﻳﺔ‪ .‬ﻳﺩﺧﻼﻥ‬
‫ﻓﻲ ﺍﻟﺗﻔﺎﻋﻼﺕ ﺍﻟﻛﻳﻣﻳﺎﺋﻳﺔ ﺑﺄﺳﻠﻭﺏ ﻭﺍﺣﺩ ﻭ ﻳﺧﺗﻠﻔﺎﻥ ﻓﻘﻁ ﻓﻲ ﺍﺗﺟﺎﻩ ﺩﻭﺭﺍﻥ ﻣﺳﺗﻭﻯ ﺍﻟﺿﻭء ﺍﻟﻣﺳﺗﻘﻁﺏ ﺣﻳﺙ ﺗﺩﻳﺭ ﺃﺣﺩﻫﻣﺎ‬
‫ﺍﻟﻣﺳﺗﻭﻯ ﺑﺎﺗﺟﺎﻩ ﺍﻟﻳﻣﻳﻥ ﺑﻣﻘﺩﺍﺭ ﻣﻌﻳﻥ ﻭ ﺍﻟﺛﺎﻧﻳﺔ ﺗﺩﻳﺭ ﺍﻟﻣﺳﺗﻭﻯ ﺑﻧﻔﺱ ﺍﻟﻣﻘﺩﺍﺭ ﻭ ﻟﻛﻥ ﺑﺎﺗﺟﺎﻩ ﺍﻟﻳﺳﺎﺭ‪ ،‬ﻭ ﻳﻁﻠﻕ ﻋﻠﻰ ﺍﻷﻭﻝ‬

‫ﺍﺳﻡ ﺍﻟﺷﺑﻳﻪ ﺍﻟﻳﻣﻳﻧﻲ ‪ (d) dextro‬ﻭ ﺍﻟﺛﺎﻧﻲ ﺍﺳﻡ ﺍﻟﺷﺑﻳﻪ ﺍﻟﻳﺳﺎﺭﻱ ‪. (l) leavo‬‬

‫ﻳﻅﻬﺭ ﺍﻟﻣﻌﻘﺩ ‪ [Co(en)2Cl2]+‬ﺇﺷﻛﺎﻝ )‪ ،(cis – trans‬ﻭ ﻳﻛﻭﻥ ﺍﻟﻧﻭﻉ ﺗﺭﺍﻧﺱ ﻏﻳﺭ ﻧﺷﻁ ﺿﻭﺋﻳﺎ ﻷﻧﻪ ﺟﺯﺉ ﻣﺗﻣﺎﺛﻝ‪ ،‬ﻭ‬
‫ﻳﻛﻭﻥ ﺍﻟﻧﻭﻉ )‪ (cis‬ﻧﺷﻁ ﺿﻭﺋﻳﺎ ﻭ ﻳﺗﻭﺍﺟﺩ ﻓﻲ ﺻﻭﺭﺓ )‪ (d,l‬ﻛﻣﺎ ﻓﻲ ﺍﻟﺷﻛﻝ ﺍﻟﺗﺎﻟﻲ‪:‬‬

‫‪Cl Cl‬‬ ‫‪Cl‬‬ ‫‪en‬‬
‫‪Cl Cl‬‬ ‫‪Cl‬‬

‫‪en en‬‬

‫‪en‬‬

‫‪en en‬‬

‫)‪(I) cis-structure (d‬‬ ‫‪Trans-structure‬‬

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‫م‪.‬ﺣﻮراء ﻣﻬﺪي‬ ‫اﻟﻤﺮﺣﻠﺔ اﻟﺜﺎﻟﺜﺔ‬ ‫ﻣﺤﺎﺿﺮات اﻟﻜﻴﻤﻴﺎء اﻟﺘﻨﺎﺳﻘﻴﺔ‬

‫ﺗﺣﺿﻳﺭ ﻭﺗﻔﺎﻋﻼﺕ ﺍﻟﻣﺭﻛﺑﺎﺕ ﺍﻟﻣﻌﻘﺩﺓ‪:‬‬

‫‪Prepration and reaction of Coordination Compounds ‬‬
‫‪ -‬ﻟﻘﺩ ﺍﺳﺗﺧﺩﻣﺕ ﻁﺭﻕ ﻋﺩﻳﺩﺓ ﻭ ﻣﺧﺗﻠﻔﺔ ﻓﻲ ﺗﺣﺿﻳﺭ ﺍﻟﻣﺭﻛﺑﺎﺕ ﺍﻟﺗﻧﺎﺳﻘﻳﺔ‪.‬ﻭ ﻧﻅﺭﺍ ﻵﻥ ﺍﻟﻣﺎء ﻳﺳﺗﺧﺩﻡ ﻓﻲ ﺣﺎﻻﺕ ﻋﺩﻳﺩﺓ‬
‫ﻣﺫﻳﺑﺎ ﻟﺗﺣﺿﻳﺭ ﺗﻠﻙ ﺍﻟﻣﻌﻘﺩﺍﺕ ‪ ،‬ﻭ ﺑﻣﺎ ﺃﻥ ﺃﻳﻭﻧﺎﺕ ﺍﻟﻔﻠﺯﺍﺕ ﺍﻟﻣﻭﺟﺑﺔ ﻳﻣﻛﻧﻬﺎ ﺃﻥ ﺗﻛﻭﻥ ﺁﺻﺭﺓ ﺗﻧﺎﺳﻘﻳﺔ ﻣﻊ ﺟﺯﻳﺋﺎﺕ‬
‫ﺍﻟﻣﺎء‪ .‬ﻟﺫﺍ ﻓﺈﻥ ﺍﻷﻳﻭﻥ ﺍﻟﻣﻭﺟﺏ ﻓﻲ ﺍﻟﻣﺫﻳﺏ ) ﺍﻟﻣﺎء( ﻳﻛﻭﻥ ﻓﻲ ﺍﻟﻭﺍﻗﻊ ﺃﻳﻭﻧﺎ ﻣﻌﻘﺩﺍ ﻭ ﻳﺷﺎﺭ ﺇﻟﻳﻪ ﺑﺎﻷﻳﻭﻥ ﺍﻟﻣﺎﺋﻲ‬
‫‪ [M(H2O)x]n+‬ﻭ ﻳﻌﺗﺑﺭ ﺃﻳﻭﻥ ﺳﺩﺍﺳﻲ ﺍﻟﻣﺎﺋﻳﺎﺕ ‪ [M(H2O)6]n+‬ﻫﻭ ﺍﻷﻣﻳﻥ ﺍﻟﻣﺎﺋﻲ ﺍﻟﺷﺎﺋﻊ ﻟﻣﻌﻅﻡ ﺍﻟﻔﻠﺯﺍﺕ ﻓﻲ‬

‫ﺍﻟﻣﺎء‪.‬‬

‫‪H2O‬‬ ‫‪n+‬‬
‫‪H2O‬‬ ‫‪OH2‬‬

‫‪OH2‬‬
‫‪M‬‬

‫‪OH2‬‬
‫‪OH2‬‬

‫ﺃﻳﻭﻥ ﺳﺩﺍﺳﻲ ﻣﺎﺋﻳﺎﺕ‬

‫‪ .۱‬ﺗﻔﺎﻋﻼﺕ ﺍﻻﺣﻼﻝ ﻓﻲ ﺍﻟﻣﺣﺎﻟﻳﻝ ﺍﻟﻣﺎﺋﻳﺔ‪:‬‬
‫ﺗﻌﺩ ﺗﻔﺎﻋﻼﺕ ﺍﻹﺣﻼﻝ ﻋﻠﻰ ﺃﻳﻭﻥ ﺳﺩﺍﺳﻲ ﻣﺎﺋﻳﺎﺕ ﻫﻲ ﺍﻷﻛﺛﺭ ﺍﺳﺗﺧﺩﺍﻣﺎ ﻓﻲ ﻁﺭﻕ ﺍﻟﺗﺣﺿﻳﺭ ﻟﻠﻣﻌﻘﺩﺍﺕ ) ﻣﻊ‬
‫ﻣﺭﺍﻋﺎﺓ ﻅﺭﻭﻑ ﺍﻟﺗﺟﺭﺑﺔ ﺍﻟﻣﺧﺗﻠﻔﺔ(‪.‬ﻭ ﻓﻳﻬﺎ ﻳﺣﺩﺙ ﺍﺳﺗﺑﺩﺍﻝ ﺟﺯﻳﺋﺎﺕ ﺍﻟﻣﺎء ﺑﻠﻳﻛﺎﻧﺩﺍﺕ ﺃﺧﺭﻯ ﺑﺷﻛﻝ ﺗﺩﺭﻳﺟﻲ ﻭ ﻗﺩ‬
‫ﻳﻛﻭﻥ ﺗﺎﻣﺎ ﺃﻭ ﻏﻳﺭ ﺗﺎﻡ‪ .‬ﻓﻌﻠﻰ ﺳﺑﻳﻝ ﺍﻟﻣﺛﺎﻝ‪ :‬ﺇﺫﺍ ﺃﺿﻔﻧﺎ ﻣﺣﻠﻭﻻ ﻣﺎﺋﻳﺎ ﻣﻥ ﺑﺭﻭﻣﻳﺩ ﺍﻟﻧﻳﻛﻝ ‪ NiBr2‬ﺇﻟﻰ ﻭﻓﺭﺓ‬
‫ﻣﻥ ﻣﺣﻠﻭﻝ ﺍﻷﻣﻭﻧﻳﺎ ﺍﻟﻣﺭﻛﺯ‪ ،‬ﻓﺈﻧﻪ ﻳﺗﻛﻭﻥ ﺃﻳﻭﻥ ﺳﺩﺍﺳﻲ ﺃﻣﻳﻥ ﺍﻟﻧﻳﻛﻝ)‪ (II‬ﺍﻟﺫﻱ ﻳﺗﺭﺳﺏ ﻛﻣﻠﺢ ﺑﻠﻭﺭﻱ ﺑﻧﻔﺳﺟﻲ ﻣﻊ‬

‫ﺃﻳﻭﻧﺎﺕ ﺍﻟﺑﺭﻭﻣﻳﺩ ‪ ،‬ﻭ ﻳﺣﺩﺙ ﺍﺳﺗﺑﺩﺍﻝ ﺗﺎﻡ‪:‬‬

‫‪[Ni(H2O)6]2+ + 6NH3 → [Ni(NH3)6]2+ + 6H2O‬‬

‫ﻓﻣﺛﻼً ﻳﺣﺿﺭ ﺍﻟﻣﻌﻘﺩ ‪ [Cu(NH3)4]SO4‬ﺑﺳﻬﻭﻟﺔ ﻭﺫﻟﻙ ﻣﻥ ﺍﻟﺗﻔﺎﻋﻝ ﺑﻳﻥ ﻣﺣﻠﻭﻝ ‪ CuSO4‬ﺍﻟﻣﺎﺋﻲ ﻭﺑﻳﻥ ﺯﻳﺎﺩﺓ ﻣﻥ‬
‫)‪: (NH3‬‬

‫‪[Cu(H2O)4]2+ + 4NH3 → [Cu(NH3)4]2+ + 4H2O‬‬

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‫م‪.‬ﺣﻮراء ﻣﻬﺪي‬ ‫اﻟﻤﺮﺣﻠﺔ اﻟﺜﺎﻟﺜﺔ‬ ‫ﻣﺤﺎﺿﺮات اﻟﻜﻴﻤﻴﺎء اﻟﺘﻨﺎﺳﻘﻴﺔ‬

‫ﺣﻳﺙ ﺗﺳﺗﺑﺩﻝ ﺟﺯﻳﺋﺎﺕ ﺍﻟﻣﺎء ﺍﻟﻣﺗﻧﺎﺳﻘﺔ ﻓﻭﺭﺍً ﻭﻓﻲ ﺩﺭﺟﺔ ﺣﺭﺍﺭﺓ ﺍﻟﻐﺭﻓﺔ ﺑﺟﺯﻳﺋﺎﺕ ﺍﻻﻣﻭﻧﻳﺎ ﻭ ﻫﺫﺍ ﻧﺳﺗﻧﺗﺞ ﻣﻥ‬
‫ﺗﻐﻳﺭ ﺍﻟﻠﻭﻥ ﻣﻥ ﺍﻷﺯﺭﻕ ﺍﻟﻔﺎﺗﺢ ﺇﻟﻰ ﺍﻷﺯﺭﻕ ﺍﻟﻐﺎﻣﻕ‪.‬‬

‫ﺇﻻ ﺃﻥ ﻣﻌﻘﺩﺍﺕ ﺳﺩﺍﺳﻲ ﺃﻣﻳﻧﺎﺕ ﺍﻟﻧﺣﺎﺱ)‪ (II‬ﻣﺛﻝ ‪ [Cu(NH3)6]Br2‬ﻳﻣﻛﻥ ﺗﺣﺿﻳﺭﻫﺎ ﺑﺎﺳﺗﻌﻣﺎﻝ ﺳﺎﺋﻝ ﺍﻷﻣﻭﻧﻳﺎ‪.‬‬

‫ﻭ ﻧﻅﺭﺍ ﻷﻥ ﺍﻟﻠﻳﻛﺎﻧﺩﺍﺕ ﺗﺣﺗﻭﻱ ﻋﻠﻰ ﺫﺭﺍﺕ ﻭﺍﻫﺑﺔ ﺗﻣﺗﻠﻙ ﺃﺯﻭﺍﺝ ﺇﻟﻛﺗﺭﻭﻧﻳﺔ ﻏﻳﺭ ﻣﺭﺗﺑﻁﺔ ﻓﺈﻥ ﻫﺫﻩ ﺍﻟﺫﺭﺍﺕ ﻗﺩ ﺗﺭﺗﺑﻁ ﺑﺄﻳﻭﻧﺎﺕ‬
‫ﺍﻟﻬﻳﺩﺭﻭﺟﻳﻥ ﻓﻲ ﺍﻟﻣﺣﻠﻭﻝ ﻣﻣﺎ ﻳﻌﻳﻕ ﺗﻛﻭﻳﻥ ﺍﻟﻣﻌﻘﺩ ﺍﻟﻔﻠﺯﻱ ﻭ ﻟﺫﻟﻙ ﻓﺈﻥ ﺗﻛﻭﻳﻥ ﺍﻟﻣﻌﻘﺩﺍﺕ ﺍﻟﻔﻠﺯﻳﺔ ﻓﻲ ﺍﻟﻭﺳﻁ ﺍﻟﻣﺎﺋﻲ ﻳﺳﺗﻠﺯﻡ ﺃﻥ‬

‫ﻳﻛﻭﻥ ﺍﻟﻭﺳﻁ ﻗﺎﻋﺩﻳﺎ ﺿﻌﻳﻔﺎ‪.‬‬

‫ﺇﻻ ﺃﻧﻪ ﻓﻲ ﺣﺎﻟﺔ ﺍﻟﻠﻳﻛﺎﻧﺩﺍﺕ ﺍﻟﻌﺿﻭﻳﺔ ﺍﻟﻣﺣﺗﻭﻳﺔ ﻋﻠﻰ ﺫﺭﺍﺕ ﻫﻳﺩﺭﻭﺟﻳﻥ ﻗﺎﺑﻠﺔ ﻟﻺﺣﻼﻝ ﻣﺛﻝ ﺍﺳﻳﺗﻳﻝ ﺃﺳﻳﺗﻭﻥ ﻓﺈﻥ ﺍﻟﻭﺳﻁ ﺍﻟﻘﺎﻋﺩﻱ‬
‫ﺍﻟﺿﻌﻳﻑ ﻳﺅﺩﻱ ﺇﻟﻰ ﻧﺯﻉ ﺑﺭﻭﺗﻭﻥ ﻣﻛﻭﻧﺎ ﺍﺳﻳﺗﻳﻝ ﺍﺳﻳﺗﻭﻧﺎﺕ ﺍﻟﺫﻱ ﻳﺗﻔﺎﻋﻝ ﻣﻊ ﺍﻟﻔﻠﺯ ﻛﻠﻳﻛﺎﻧﺩ ﺛﻧﺎﺋﻲ ﺍﻟﺳﻥ ﺫﺍﺕ ﺷﺣﻧﺔ ﺳﺎﻟﺑﺔ‪ ،‬ﻣﺛﺎﻝ‪:‬‬

‫ﻳﺗﺭﺳﺏ ﺍﻟﻣﻌﻘﺩ ]‪ [Cr(acac)3‬ﻣﻥ ﻣﺣﻠﻭﻝ ﺍﻟﻛﺭﻭﻡ )‪ (III‬ﻭ ﺍﺳﻳﺗﻳﻝ ﺍﺳﻳﺗﻭﻥ ﻓﻲ ﻭﺟﻭﺩ ﻗﺎﻋﺩﺓ ﺿﻌﻳﻔﺔ ﻁﺑﻘﺎ ﻟﻠﺗﻔﺎﻋﻝ ﺍﻟﺗﺎﻟﻲ‪:‬‬

‫‪[Cr(H2O)6]3+ + 3 acac‾ → [Cr(acac)3] + 6H2O‬‬

‫‪ -‬ﻳﺗﺑﻠﻭﺭ ﻣﻥ ﺍﻟﻣﺣﻠﻭﻝ ﺍﻟﻣﺎﺋﻲ ﻣﻌﻘﺩ ﺳﻳﺎﻧﻭ ﺣﺩﻳﺩﺍﺕ)‪ (II‬ﺍﻟﺑﻭﺗﺎﺳﻳﻭﻡ ﻣﻥ ﺗﻔﺎﻋﻝ ﻣﺣﻠﻭﻝ ﻛﺑﺭﻳﺗﺎﺕ ﺍﻟﺣﺩﻳﺩ)‪ (II‬ﺍﻟﻣﺎﺋﻲ ﻣﻊ‬
‫ﻭﻓﺭﺓ ﻣﻥ ﻣﺣﻠﻭﻝ ﺳﻳﺎﻧﻳﺩ ﺍﻟﺑﻭﺗﺎﺳﻳﻭﻡ‪.‬‬

‫‪[Fe(H2O)6]2+ + 6CN‾ → [Fe(CN)6]4‾ + 6H2O‬‬

‫‪ -۲‬ﺗﻔﺎﻋﻼﺕ ﺍﻹﺣﻼﻝ ﻓﻲ ﺍﻟﻣﺫﻳﺑﺎﺕ ﻏﻳﺭ ﺍﻟﻣﺎﺋﻳﺔ‪:‬‬

‫ﻫﻧﺎﻙ ﻋﺎﻣﻼﻥ ﺭﺋﻳﺳﻳﺎﻥ ﻳﺳﺗﻌﻣﻝ ﺑﺳﺑﺑﻬﻣﺎ ﺃﺣﻳﺎﻧﺎً ﺍﻟﻣﺫﻳﺏ ﻏﻳﺭ ﺍﻟﻣﺎﺋﻲ ﻭﻫﻣﺎ‪:‬‬
‫‪-1‬ﻋﻧﺩﻣﺎ ﻳﻛﻭﻥ ﻻﻳﻭﻥ ﺍﻟﻔﻠﺯ ﺃﻟﻔﺔ ﻛﺑﻳﺭﺓ ﻧﺣﻭ ﺍﻟﻣﺎء ﻣﺛﻝ ﺍﻳﻭﻧﺎﺕ )‪.Cr(III),Fe(III),AI(III‬‬

‫‪-2‬ﻋﺩﻡ ﺫﻭﺑﺎﻥ ﺍﻟﻠﻳﻛﺎﻧﺩ ﻓﻲ ﺍﻟﻣﺎء‪.‬‬

‫ﺃﻥ ﺃﺿﺎﻓﺔ ﺍﻟﻠﻳﻛﺎﻧﺩ ﺍﻟﻘﺎﻋﺩﻱ ﺇﻟﻰ ﺍﻟﻣﺣﻠﻭﻝ ﺍﻟﻣﺎﺋﻲ ﺍﻟﺣﺎﻭﻱ ﻋﻠﻰ ﺍﻻﻳﻭﻧﺎﺕ ﺍﻟﻣﺫﻛﻭﺭﺓ ﻳﺅﺩﻱ ﺇﻟﻰ ﺗﻛﻭﻳﻥ ﺍﻟﻬﻳﺩﺭﻭﻛﺳﻳﺩﺍﺕ ﻋﻠﻰ ﻫﻳﺋﺔ‬

‫ﺭﺍﺳﺏ ﺟﻳﻼﺗﻳﻧﻲ ﻭﻟﻳﺱ ﺍﻟﻣﻌﻘﺩ ﺍﻟﺣﺎﻭﻱ ﻋﻠﻰ ﺍﻟﻠﻳﻛﺎﻧﺩ ﺍﻟﻣﺿﺎﻑ ﺃﻳﻥ ﺍﻻﻳﻭﻧﺎﺕ ﺗﺳﻠﻙ ﺳﻠﻭﻙ ﺣﺎﻣﺽ ﻟﻭﻳﺱ ﻛﻣﺎ ﻓﻲ ﺍﻟﻣﻌﺎﺩﻻﺕ ‪:‬‬

‫‪Cr(H2O)6]+3 + 3en‬‬ ‫‪H2O [Cr(H2O)3(OH)3] + 3enH3+‬‬

‫ﺃﻣﺎ ﺃﺫﺍ ﺍﺳﺗﻌﻣﻠﻧﺎ ﻋﻭﺿﺎً ﻋﻥ ﺫﻟﻙ ﻣﻠﺢ ﺍﻟﻛﺭﻭﻡ ﺍﻟﻼﻣﺎﺋﻲ ﻭ ﻣﺫﻳﺏ ﻏﻳﺭ ﻣﺎﺋﻲ ﻓﺄﻥ ﺍﻟﺗﻔﺎﻋﻝ ﺳﻳﺟﺭﻱ ﺑﺳﻬﻭﻟﺔ ﻣﻌﻁﻳﺎً ﺍﻟﻣﻌﻘﺩ‬

‫‪ [Cr(en)3]CI3‬ﺍﻳﺛﺭ‬ ‫‪.[Cr(en)3]3+‬‬

‫‪CrCI3‬‬ ‫‪+ 3en‬‬

‫ﻛﺛﻳﺭ ﻣﻥ ﻣﻌﻘﺩﺍﺕ ﺍﻣﻭﻧﻳﺎﺕ ﺍﻟﻛﺭﻭﻡ)‪ Ammine chromium(III) complexes .(III‬ﻳﺗﻡ ﺗﺣﺿﻳﺭﻫﺎ ﻓﻲ ﻣﺫﻳﺑﺎﺕ ﻏﻳﺭﻣﺎﺋﻳﺔ ﻣﺛﻝ‬

‫ﺛﻧﺎﺋﻲ ﻣﺛﻳﻝ ﻓﻭﺭﻣﺎﻣﻳﺩ )‪ (DMF‬ﻟﺗﺣﺿﻳﺭ ‪ cis[Cr(en)2CI2]CI‬ﺑﻧﺗﺎﺋﺞ ﺟﻳﺩﺓ ﻭﻋﻥ ﻁﺭﻳﻕ ﺍﻟﺗﻔﺎﻋﻝ ﺍﻟﻣﺑﺎﺷﺭ‪:‬‬

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‫م‪.‬ﺣﻮراء ﻣﻬﺪي‬ ‫اﻟﻤﺮﺣﻠﺔ اﻟﺜﺎﻟﺜﺔ‬ ‫ﻣﺤﺎﺿﺮات اﻟﻜﻴﻤﻴﺎء اﻟﺘﻨﺎﺳﻘﻴﺔ‬

‫‪[Cr(DMF)3CI3] + 2en‬‬ ‫‪cis-[Cr(en)2CI2]CI‬‬

‫ﻭ ﺍﻟﻠﻳﻛﺎﻧﺩﺍﺕ ﻣﻌﻅﻣﻬﺎ ﺟﺯﻳﺋﺎﺕ ﻋﺿﻭﻳﺔ ﻣﺗﻌﺎﺩﻟﺔ ﻻ ﺗﺫﻭﺏ ﻓﻲ ﺍﻟﻣﺎء ﻭ ﺑﺎﻟﺗﺎﻟﻲ ﻓﺈﻥ ﺗﺣﺿﻳﺭ ﻣﻌﻘﺩﺍﺗﻬﺎ ﻣﻊ ﺃﻳﻭﻥ ﺍﻟﻔﻠﺯ ﻳﺳﺗﻠﺯﻡ‬

‫ﺇﺫﺍﺑﺗﻬﺎ ﻓﻲ ﻣﺫﻳﺑﺎﺕ ﻋﺿﻭﻳﺔ ﻣﺛﻝ ﺍﻟﻛﺣﻭﻝ ﻛﻣﺎ ﻓﻲ ﺣﺎﻟﺔ ﺗﺣﺿﻳﺭ ﻣﻌﻘﺩﺍﺕ ﺛﻧﺎﺋﻲ ﺍﻟﺑﻳﺭﻳﺩﺍﻳﻝ ‪.‬‬
‫‪[Fe(H2O)6]2+ + 3bipy → [Fe(bipy)3]2+ + 6H2O‬‬

‫‪ -۳‬ﺗﻔﺎﻋﻼﺕ ﺍﻻﺣﻼﻝ ﺑﻐﻳﺎﺏ ﺍﻟﻣﺫﻳﺏ‬
‫ﺍﻟﺗﻔﺎﻋﻝ ﺍﻟﻣﺑﺎﺷﺭ ﺑﻳﻥ ﺍﻟﻣﻠﺢ ﺍﻟﻼﻣﺎﺋﻲ ﻭ ﺍﻟﻠﻳﻛﺎﻧﺩ ﺍﻟﺳﺎﺋﻝ ﻳﺳﺗﻌﻣﻝ ﺃﻳﺿﺎً ﻟﺗﺣﺿﻳﺭ ﺍﻟﻣﻌﻘﺩﺍﺕ ﺍﻟﻔﻠﺯﻳﺔ ﻛﻣﺎ ﻓﻲ ﺇﺿﺎﻓﺔ ﺍﻟﻣﺎء ﺇﻟﻰ‬

‫ﺳﺎﺋﻝ ﺍﻻﻣﻭﻧﻳﺎ ﺛﻡ ﺍﻟﺗﺑﺧﻳﺭ ﺣﺗﻰ ﺍﻟﺟﻔﺎﻑ ‪.‬‬

‫‪NiCI2 +6 NH3‬‬ ‫‪[Ni(NH3)6]CI2‬‬

‫ﻳﻭﺟﺩ ﺍﻟﻌﺩﻳﺩ ﻣﻥ ﻣﻌﻘﺩﺍﺕ ﺍﻵﻣﻭﻧﻳﺎ ﻻ ﻳﻣﻛﻥ ﺗﺣﺿﻳﺭﻫﺎ ﻓﻲ ﺍﻟﻣﺎء ﺑﺳﺑﺏ ﺗﺭﺳﺏ ﺍﻟﻬﻳﺩﺭﻭﻛﺳﻳﺩﺍﺕ ﺍﻟﻔﻠﺯﻳﺔ ﻓﻣﺛﻼ ﻛﻠﻭﺭﻳﺩ ﺍﻟﺣﺩﻳﺩ)‪(II‬‬

‫ﻳﻭﻟﺩ ﺍﻟﻬﻳﺩﺭﻭﻛﺳﻳﺩ ﻣﻊ ﻣﺣﻠﻭﻝ ﺍﻷﻣﻭﻧﻳﺎ ﺍﻟﻣﺎﺋﻲ ﺃﻣﺎ ﺇﺿﺎﻓﺔ ﺳﺎﺋﻝ ﺍﻷﻣﻭﻧﻳﺎ ﻋﻠﻰ ﻛﻠﻭﺭﻳﺩ ﺍﻟﺣﺩﻳﺩ)‪ (II‬ﻋﻧﺩ ﺩﺭﺟﺔ ﺍﻟﺣﺭﺍﺭﺓ ﺍﻻﻋﺗﻳﺎﺩﻳﺔ‬

‫ﻳﻧﺗﺞ ﻋﻧﻪ ﺗﻛﻭﻥ ﺍﻟﺳﺩﺍﺳﻲ ﺃﻣﻳﻥ‬

‫‪FeCl2 + 6NH3 → [Fe(NH3)6]Cl2‬‬

‫ﺃﻥ ﺃﺣﺩ ﺍﻟﻁﺭﻕ ﺍﻟﻣﺳﺗﻌﻣﻠﺔ ﻟﺗﺣﺿﻳﺭ ‪ [pt(en)2]CI2‬ﻭ ‪ [pt(en)3]CI4‬ﻫﻭ ﺍﻟﺗﻔﺎﻋﻝ ﺍﻟﻣﺑﺎﺷﺭ ﺑﻳﻥ ﺍﺛﻳﻠﻳﻥ ﺛﻧﺎﺋﻲ ﺍﻣﻳﻥ ﻭ‬
‫‪ PtCI2‬ﻭ ‪ PtCI4‬ﻋﻠﻰ ﺍﻟﺗﻭﺍﻟﻲ‪.‬‬

‫‪ -٥‬ﺗﺣﺿﻳﺭ ﺍﻟﻣﻌﻘﺩﺍﺕ ﺑﺎﻟﺗﻔﻛﻙ ﺍﻟﺣﺭﺍﺭﻱ‪:‬‬

‫ﻳﻌﺗﺑﺭ ﺍﻟﺗﻔﻛﻙ ﺍﻟﺣﺭﺍﺭﻱ ﻣﻥ ﺗﻔﺎﻋﻼﺕ ﺍﻻﺳﺗﺑﺩﺍﻝ ﻓﻲ ﺍﻟﺣﺎﻟﺔ ﺍﻟﺻﻠﺑﺔ ﻓﺎﻟﺯﻳﺎﺩﺓ ﻓﻲ ﺩﺭﺟﺔ ﺍﻟﺣﺭﺍﺭﺓ ﺗﺅﺩﻱ ﺇﻟﻰ ﻓﻘﺩﺍﻥ ﻟﻳﻛﺎﻧﺩﺍﺕ‬

‫ﺍﻟﺗﻧﺎﺳﻕ ﺍﻟﻣﺗﻁﺎﻳﺭﺓ ﻭ ﺗﺣﻝ ﻣﺣﻠﻬﺎ ﻓﻲ ﺍﻟﻛﺭﺓ ﺍﻟﺗﻧﺎﺳﻘﻳﺔ ﺍﻳﻭﻧﺎﺕ ﺍﻟﻣﻌﻘﺩ‪.‬‬

‫‪[Cu(H2O)4]SO4.H2O‬‬ ‫‪[CuSO4] + 5H2O‬‬

‫ﺃﺯﺭﻕ ﺍﻟﻠﻭﻥ‬ ‫ﻋﺩﻳﻡ ﺍﻟﻠﻭﻥ‬

‫‪[Rh(NH3)5H2O]I3‬‬ ‫‪100◦C [Rh(NH3)5I]I2 + H2O‬‬

‫‪ -٦‬ﺗﻔﺎﻋﻼﺕ ﺍﻷﻛﺳﺩﺓ ﻭﺍﻹﺧﺗﺯﺍﻝ‪:‬‬
‫ﻓﻳﻣﺎ ﺗﻘﺩﻡ ﺍﺳﺗﺧﺩﻣﻧﺎ ﺃﻣﺛﻠﺔ ﻟﻡ ﺗﺗﻐﻳﺭ ﻓﻳﻬﺎ ﺣﺎﻟﺔ ﺗﺄﻛﺳﺩ ﺍﻟﻔﻠﺯ ﺧﻼﻝ ﻋﻣﻠﻳﺔ ﺍﻟﺗﺣﺿﻳﺭ‪ .‬ﺍﻻ ﺃﻧﻪ ﻳﻭﺟﺩ ﺍﻟﻌﺩﻳﺩ ﻣﻥ ﺍﻟﻠﻳﻛﺎﻧﺩﺍﺕ‬
‫ﺑﺎﺳﺗﻁﺎﻋﺗﻬﺎ ﺃﻥ ﺗﻌﻣﻝ ﺑﻭﺻﻔﻬﺎ ﻋﻭﺍﻣﻝ ﻣﺧﺗﺯﻟﺔ‪ .‬ﻛﻣﺎ ﻳﻣﻛﻥ ﺟﻌﻝ ﺣﺎﻻﺕ ﺍﻟﺗﺄﻛﺳﺩ ﺍﻟﻌﺎﻟﻳﺔ ﻟﺑﻌﺽ ﺍﻟﻔﻠﺯﺍﺕ ﻣﺳﺗﻘﺭﺓ ﺑﺎﻟﺗﺂﺻﺭ‬

‫ﺍﻟﺗﻧﺎﺳﻘﻲ‪.‬ﻭ ﻣﻥ ﺍﻷﻣﺛﻠﺔ ﺍﻟﻣﻌﺭﻭﻓﺔ ﻋﻠﻰ ﻫﺫﺍ ﺍﻟﻧﻭﻉ ﺍﻟﺛﺎﻧﻲ ﻫﻭ ﻛﻳﻣﻳﺎء ﺍﻟﻛﻭﺑﻠﺕ‪:‬‬

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‫م‪.‬ﺣﻮراء ﻣﻬﺪي‬ ‫اﻟﻤﺮﺣﻠﺔ اﻟﺜﺎﻟﺜﺔ‬ ‫ﻣﺤﺎﺿﺮات اﻟﻜﻴﻤﻴﺎء اﻟﺘﻨﺎﺳﻘﻴﺔ‬

‫ﺗﻌﺩ ﺃﻣﻼﺡ ﺍﻟﻛﻭﺑﻠﺕ )‪(II‬ﻛﻣﻠﺢ ﺑﺳﻳﻁ ﻳﻛﻭﻥ ﻣﺳﺗﻘﺭ ﺃﻛﺛﺭ ﻣﻥ ﺃﻳﻭﻥ ﺍﻟﻛﻭﺑﻠﺕ )‪ (III‬ﻓﻲ ﺣﻳﻥ ﺗﺻﺑﺢ ﺣﺎﻟﺔ ﺍﻻﻛﺳﺩﺓ ﺍﻟﺛﻼﺛﻳﺔ ﺍﻟﺣﺎﻟﺔ‬

‫ﺍﻟﻣﺳﺗﻘﺭﺓ ﻋﻧﺩﻣﺎ ﻳﺗﻧﺎﺳﻕ ﺍﻟﻛﻭﺑﻠﺕ ﻣﻊ ﺍﻧﻭﺍﻉ ﻣﻌﻳﻧﺔ ﻣﻥ ﺍﻟﻠﻳﻛﺎﻧﺩﺍﺕ ‪.‬ﻭ ﺍﻟﺳﺑﺏ ﺍﻻﺧﺭ ﻓﻲ ﺍﺳﺗﺧﺩﺍﻡ ﺍﻣﻼﺡ ﺍﻟﻛﻭﺑﻠﺕ ﺍﻟﺛﻧﺎﺋﻳﺔ ﺍﻥ‬
‫ﺗﻔﺎﻋﻼﺕ ﺍﻻﺳﺗﺑﺩﺍﻝ ﻓﻲ ﻣﻌﻘﺩﺍﺕ )‪ Co(II‬ﺑﻁﻳﺋﺔ ﺟﺩﺍً‪ ،‬ﻟﺫﻟﻙ ﺗﺣﺿﺭ ﺃﻣﻳﻧﺎﺕ ﺍﻟﻛﻭﺑﻠﺕ ﺍﻟﺛﻼﺛﻲ ﻣﻥ ﺍﻟﻣﺣﻠﻭﻝ ﺍﻟﻣﺎﺋﻲ ﻭ ﺫﻟﻙ ﺑﻣﺯﺝ‬

‫ﻣﺣﻠﻭﻝ ﻣﻛﻭﻥ ﻣﻥ ﺃﻳﻭﻥ ﺍﻟﻛﻭﺑﻠﺕ )‪ (II‬ﺍﻟﻣﺎﺋﻲ ﻭ ﻛﻠﻭﺭﻳﺩ ﺍﻷﻣﻭﻧﻳﻭﻡ ﻭ ﺍﻷﻣﻭﻧﻳﺎ ﻭ ﺍﻟﻔﺣﻡ ﺍﻟﺣﺟﺭﻱ ﻛﻌﺎﻣﻝ ﻣﺳﺎﻋﺩ‪.‬‬

‫‪4[Co(H2O)6]Cl2 + 4NH4Cl + 20NH3 +O2 → 4[Co(NH3)6]Cl3 + 26H2O‬‬

‫ﺇﻻ ﺃﻥ ﺍﻷﻛﺛﺭ ﺷﻳﻭﻋﺎ ﻫﻲ ﺗﻔﺎﻋﻼﺕ ﺍﻻﺧﺗﺯﺍﻝ ﺍﻟﺗﻲ ﺗﺣﺩﺙ ﻟﻠﻌﻧﺻﺭ ﺍﻻﻧﺗﻘﺎﻟﻲ ﺧﻼﻝ ﻋﻣﻠﻳﺔ ﺍﻟﺗﺣﺿﻳﺭ ﺣﻳﺙ ﻳﻌﺩ ﺍﻟﻠﻳﻛﺎﻧﺩ ﻧﻔﺳﻪ‬
‫ﻋﺎﻣﻼ ﻣﺧﺗﺯﻻ‪ ،‬ﻭ ﻣﻥ ﺃﻣﺛﻠﺗﻬﺎ‪ :‬ﻓﻲ ﺗﺣﺿﻳﺭ ﺍﻳﺳﻭﻣﺭﺍﺕ ﺳﻳﺯ ﻭ ﺗﺭﺍﻧﺱ ﺛﻧﺎﺋﻲ ﺃﻭﻛﺯﺍﻻﺗﻭ ﺛﻧﺎﺋﻲ ﻣﺎﺋﻳﺎﺕ ﻛﺭﻭﻣﺎﺕ )‪ (III‬ﺍﻟﺑﻭﺗﺎﺳﻳﻭﻡ‬

‫ﻳﺧﺗﺯﻝ ﺛﻧﺎﺋﻲ ﻛﺭﻭﻣﺎﺕ ﺍﻟﺑﻭﺗﺎﺳﻳﻭﻡ ﺑﺣﺎﻣﺽ ﺍﻻﻭﻛﺯﺍﻟﻳﻙ‬

‫‪K2Cr2O7 + 7H2C2O4 → 2K[Cr(C2O4)2(H2O)2] + 6CO2 + 3H2O‬‬

‫‪ -٦‬ﺍﻟﺗﺣﻔﻳﺯ‪ :‬ﺗﺳﺗﺧﺩﻡ ﺍﻟﻣﺣﻔﺯﺍﺕ ﻟﺯﻳﺎﺩﺓ ﺳﺭﻋﺔ ﺍﻟﺗﻔﺎﻋﻝ ﻭ ﺍﻧﻭﺍﻋﻬﺎ‪:‬‬

‫• ﻣﺣﻔﺯﺍﺕ ﻏﻳﺭ ﻣﺗﺟﺎﻧﺳﺔ )‪ (Hterogenous Catalysts‬ﻭﻫﻲ ﺍﻟﺗﻲ ﺗﺧﺗﻠﻑ ﻓﻳﻬﺎ ﺣﺎﻟﺔ ﺍﻟﻁﻭﺭ ﺍﻟﻣﺣﻔﺯ ﻋﻥ ﺣﺎﻟﺔ‬
‫ﺍﻟﻣﻭﺍﺩ ﺍﻟﻣﺗﻔﺎﻋﻠﺔ ‪.‬‬

‫• ﺍﻟﻣﺣﻔﺯﺍﺕ ﺍﻟﻣﺗﺟﺎﻧﺳﺔ )‪ (Homogeneous catalysts‬ﻭﻫﻲ ﺍﻟﺗﻲ ﺗﺗﺷﺎﺑﻪ ﺣﺎﻟﺔ ﺍﻟﻣﺣﻔﺯ ﻣﻊ ﺣﺎﻟﺔ ﺍﻟﻣﻭﺍﺩ ﺍﻟﻣﺗﻔﺎﻋﻠﺔ ‪.‬‬

‫ﺳﻧﻌﻁﻲ ﺃﻣﺛﻠﺔ ﻋﻥ ﺍﺳﺗﺧﺩﺍﻡ ﺍﻟﻣﺣﻔﺯﺍﺕ ﺍﻟﻣﺗﺟﺎﻧﺳﺔ ﻭ ﺍﻟﻐﻳﺭ ﻣﺗﺟﺎﻧﺳﺔ ‪ :‬ﻣﻥ ﺃﺷﻬﺭ ﺍﻷﻣﺛﻠﺔ ﻻﺳﺗﺧﺩﺍﻡ ﺍﻟﻣﺣﻔﺯﺍﺕ ﺍﻟﻐﻳﺭ‬

‫ﻣﺗﺟﺎﻧﺳﺔ ﻫﻭ ﺗﺣﺿﻳﺭ ﺍﻟﻣﺭﻛﺏ ‪ [Co(NH3)6]Cl3‬ﺑﺎﺳﺗﺧﺩﺍﻡ ﺑﻌﺽ ﺍﻟﺳﻁﻭﺡ ﺍﻟﺻﻠﺑﺔ ﻛﺎﻟﻔﺣﻡ ﺍﻟﺧﺷﺑﻲ ‪ ،‬ﻓﻌﻧﺩ ﺗﺳﺧﻳﻧﻪ‬

‫ﻟﺳﺎﻋﺎﺕ ﻻ ﻳﺗﻐﻳﺭ ﻟﻭﻧﻪ ﺍﻷﺻﻔﺭ ﺍﻟﺑﺭﺗﻘﺎﻟﻲ ﻭ ﺑﻭﺟﻭﺩ ﺍﻟﻔﺣﻡ ﻳﻅﻬﺭ ﺍﻟﻠﻭﻥ ﺍﻷﺣﻣﺭ ‪[Co(NH3)5(H2O)]+3‬‬

‫‪[Co(H2O)6]CI2‬‬ ‫‪NH3,H2O,HCI‬‬

‫‪[Co(NH3)5CI]CI2‬‬

‫‪O2 ,NH4CI‬‬

‫‪NH3,H2O,HCI‬‬

‫‪[Co(H2O)6]CI2‬‬ ‫‪ O2 ,NH4CI‬ﻓﺣﻡ‬ ‫‪[Co(NH3)6]CI3‬‬

‫ﻭﺗﺗﻡ ﻋﻣﻠﻳﺔ ﺍﻟﺗﺣﺿﻳﺭ ﻣﻥ ﺧﻼﻝ ﻣﻳﻛﺎﻧﻳﻛﻳﺔ ﻭﺗﺗﻡ ﻋﻣﻠﻳﺔ ﺍﻻﻛﺳﺩﺓ ﻣﻥ ﺧﻼﻝ ﺗﻛﻭﻥ ﻣﺭﻛﺏ ﺟﺳﺭﻱ ﻧﺷﻁ‬

‫‪[Co(H2O)6]+2‬‬ ‫‪[Co(NH3)(H2O)5]+2‬‬ ‫‪[Co(NH3)2(H2O)4]+2‬‬ ‫‪[Co(NH3)6]+2‬‬

‫‪+O2 [(NH3)5Co—O—O—Co(NH3)5]+4 +2NH3‬‬

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‫ﺑﻭﺟﻭﺩ ﺍﻟﻔﺣﻡ \ﺳﺭﻳﻊ‬ ‫‪[Co(NH3)6]+3‬‬
‫‪NH3‬‬
‫‪[Co(NH3)5(OH)]+2‬‬

‫‪ [Co(NH3)5CI]+2‬ﺑﻁﻲ‬

‫ﺃﻣﺎ ﺍﻟﻣﺣﻔﺯﺍﺕ ﺍﻟﻣﺗﺟﺎﻧﺳﺔ ﻓﺑﻌﺽ ﺗﻔﺎﻋﻼﺕ ﻣﻌﻘﺩﺍﺕ ﺍﻟﺑﻼﺗﻳﻥ )‪ (IV‬ﻋﺎﺩ ًﺓ ﺑﻁﻳﺋﺔ ﺇﻻ ﺑﻭﺟﻭﺩ ﻣﺣﻔﺯ ﺍﻟﺑﻼﺗﻳﻥ )‪ (II‬ﺍﻟﺫﻱ ﻳﺟﻌﻝ‬

‫ﺍﻟﺗﻔﺎﻋﻝ ﻳﺟﺭﻱ ﺑﺳﻬﻭﻟﺔ ﻭﺩﻭﻥ ﺍﻟﺣﺎﺟﺔ ﺍﻟﻰ ﻅﺭﻭﻑ ﺻﻌﺑﺔ ﻭ ﺗﺳﺗﺧﺩﻡ ﺣﺎﻟﻳﺎً ﻟﺗﺣﺿﻳﺭ ﻣﺭﻛﺑﺎﺕ ﺍﻟﺑﻼﺗﻳﻥ ﺍﻟﺭﺑﺎﻋﻲ ‪،‬ﻭﻋﻠﻰ ﻫﺫﺍ‬
‫ﺍﻷﺳﺎﺱ ﺗﺣﺿﺭ ﺍﻟﻣﻌﻘﺩﺍﺕ ﺗﺭﺍﻧﺱ ‪ [PtA4X2]2+‬ﻋﻥ ﻁﺭﻳﻕ ﺃﻛﺳﺩﺓ ﺍﻟﻣﺭﻛﺏ ‪ [PtA4]2+‬ﺑﻣﺳﺎﻋﺩﺓ ‪ X2‬ﺃﻭ ﺑﻭﺟﻭﺩ ﺯﻳﺎﺩﺓ ﻣﻥ ﻣﻥ‬

‫‪ X-‬ﻭ ﺑﻭﺟﻭﺩ ﻛﻣﻳﺎﺕ ﻛﺎﻓﻳﺔ ﻣﻥ ﺍﻟﻣﺣﻔﺯ‪ [PtA4]+2‬ﻭ ﻣﺛﺎﻝ ﻟﺫﻟﻙ ﻫﻭ ﺍﻟﻔﺎﻋﻝ ﺑﻳﻥ ‪ [Pt(NH3)4CI2]2+‬ﻭ ‪ Br-‬ﺑﻭﺟﻭﺩ‬
‫‪.[Pt(NH3)4]2+‬‬

‫‪Trans-[Pt(NH3)4CI2]2+ +2Br-‬‬ ‫‪Trans-[Pt(NH3)4Br2]2+ + 2CI-‬‬

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‫ﺍﺳﺗﻘﺭﺍﺭﻳﺔ ﺍﻷﻳﻭﻧﺎﺕ ﺍﻟﻣﻌﻘﺩﺓ ﻓﻲ ﺍﻟﻣﺣﻠﻭﻝ‬

‫ﺷﻐﻠﺕ ﺍﻟﻛﻳﻣﻳﺎء ﺍﻟﻔﺭﺍﻏﻳﺔ )‪ (stereochemistry‬ﻟﻠﻣﺭﻛﺑﺎﺕ ﺍﻟﺗﻧﺎﺳﻘﻳﺔ ﺍﻫﺗﻣﺎﻡ ﺍﻟﺑﺎﺣﺛﻳﻥ ﻟﺳﻧﻳﻥ ﻋﺩﻳﺩﺓ ‪ ،‬ﺇﻻ ﺃﻥ‬
‫ﺍﻻﻫﺗﻣﺎﻡ ﺍﻟﺷﺩﻳﺩ ﻟﻠﺣﺻﻭﻝ ﻋﻠﻰ ﻣﻌﻘﺩﺍﺕ ﺛﺎﺑﺗﺔ ﻭ ﻣﺳﺗﻘﺭﺓ ﺣﺭﺍﺭﻳﺎ ﻟﻼﺳﺗﻔﺎﺩﺓ ﻣﻧﻬﺎ ﻓﻲ ﺷﺗﻰ ﺃﻧﻭﺍﻉ ﺍﻟﺻﻧﺎﻋﺔ ﺟﺫﺏ ﺍﻧﺗﺑﺎﻩ‬
‫ﺍﻟﺑﺎﺣﺛﻳﻥ ﺣﺩﻳﺛﺎ ﻭﻟﻔﻬﻡ ﻛﻳﻣﻳﺎء ﻣﺣﺎﻟﻳﻝ ﺍﻟﻔﻠﺯﺍﺕ ﻳﺟﺏ ﻣﻊ ﺃﻥ ﻧﻌﺭﻑ ﻁﺑﻳﻌﺔ ﻭ ﺍﺳﺗﻘﺭﺍﺭﻳﺔ ﺍﻟﻣﻌﻘﺩﺍﺕ ﺍﻟﺗﻲ ﺗﻛﻭﻧﻬﺎ ﺍﻻﻳﻭﻧﺎﺕ‬
‫ﺍﻟﻔﻠﺯﻳﺔ ﻣﻊ ﺍﻟﻣﺫﻳﺏ ﻭ ﻣﻊ ﺍﻟﻠﻳﻛﺎﻧﺩﺍﺕ ﺍﻟﻣﻭﺟﻭﺩﺓ ﻓﻲ ﺍﻟﻣﺣﻠﻭﻝ ‪.‬ﺃﻥ ﺇﺿﺎﻓﺔ ﺍﻟﻣﻭﺍﺩ ﺍﻟﻣﻛﻭﻧﺔ ﻟﻠﻣﻌﻘﺩﺍﺕ ‪(Complexing‬‬
‫)‪ agent‬ﺇﻟﻰ ﺍﻟﻣﺎء ﻳﻭﻟﺩ ﻣﺭﻛﺑﺎﺕ ﻣﻌﻘﺩﺓ ﺛﺎﺑﺗﺔ ﻭ ﺫﺍﺋﺑﺔ ﻻﻳﻭﻧﺎﺕ ﺍﻟﻔﻠﺯﺍﺕ ‪ ،‬ﻭﻋﻧﺩ ﺇﺿﺎﻓﺔ ﺍﻻﻣﻭﻧﻳﺎ ﺇﻟﻰ ﻣﺣﻠﻭﻝ ﻣﻠﺢ ﺍﻟﻧﺣﺎﺱ‬
‫ﺍﻟﺛﻧﺎﺋﻲ ﻳﺣﺩﺙ ﺗﻔﺎﻋﻝ ﺳﺭﻳﻊ ﺗﺣﻝ ﻓﻳﻪ ﺟﺯﻳﺋﺎﺕ ﺍﻻﻣﻭﻧﻳﺎ ﻣﺣﻝ ﺟﺯﻳﺋﺎﺕ ﺍﻟﻣﺎء ﺍﻟﻣﺗﻧﺎﺳﻘﺔ ﻣﻊ ﺍﻻﻳﻭﻥ ﺍﻟﻔﻠﺯﻱ ﻭﻋﻠﻰ ﺍﻟﺭﻏﻡ ﻣﻥ ﺇﻥ‬
‫ﻧﺎﺗﺞ ﺍﻟﺗﻔﺎﻋﻝ ﻳﺭﻣﺯ ﻟﻪ ﺑﺎﻟﺻﻳﻐﺔ ‪ [Cu(NH3)4]+2‬ﻓﻔﻲ ﺍﻟﻭﺍﻗﻊ ﺗﺗﻛﻭﻥ ﻋﺩﺓ ﻧﻭﺍﺗﺞ ﻣﺗﻧﻭﻋﺔ ﻭ ﺍﻟﻛﻣﻳﺔ ﺍﻟﻧﺳﺑﻳﺔ ﻟﻛﻝ ﻧﻭﻉ ﻳﻌﺗﻣﺩ‬

‫ﻋﻠﻰ ﺗﺭﺍﻛﻳﺯ ﺍﻳﻭﻥ ﺍﻟﻧﺣﺎﺳﻳﻙ ﻭ ﺍﻻﻣﻭﻧﻳﺎ‬

‫ﺃﻥ ﺍﻟﻣﻌﻠﻭﻣﺎﺕ ﺍﻟﺗﻲ ﺗﺟﻣﻌﺕ ﻟﻣﺛﻝ ﻫﺫﻩ ﺍﻟﺩﺭﺍﺳﺎﺕ ﻳﻣﻛﻥ ﺇﻥ ﻳﻌﺑﺭ ﻋﻧﻬﺎ ﺑﺛﻭﺍﺑﺕ ﺍﻻﺳﺗﻘﺭﺍﺭﻳﺔ )‪ (Stability Constants‬ﻭﻟﻘﺩ‬
‫ﻭﺟﺩ ﺃﻥ ﺣﺎﺻﻝ ﺿﺭﺏ ﺗﺭﺍﻛﻳﺯ ﺍﻟﻣﻭﺍﺩ ﺍﻟﻧﺎﺗﺟﺔ ﻟﺧﻠﻳﻁ ﺗﻔﺎﻋﻝ ﻣﻭﺟﻭﺩ ﻓﻲ ﺣﺎﻟﺔ ﺍﻟﺗﻭﺍﺯﻥ ﻭ ﻓﻲ ﺩﺭﺟﺔ ﺣﺭﺍﺭﺓ ﻣﻌﻳﻧﺔ ﻣﻘﺳﻣﺔ ﻋﻠﻰ‬
‫ﺣﺎﺻﻝ ﺿﺭﺏ ﺗﺭﺍﻛﻳﺯ ﺍﻟﻣﻭﺍﺩ ﺍﻟﻣﺗﻔﺎﻋﻠﺔ ﻳﺳﺎﻭﻱ ﻛﻣﻳﺔ ﺛﺎﺑﺗﺔ ‪ ،‬ﻭﺍﻥ ﺛﻭﺍﺑﺕ ﺍﻟﺗﻭﺍﺯﻥ ‪ K1, K2,K3, K4‬ﺗﺳﻣﻰ ﺛﻭﺍﺑﺕ ﺍﻻﺳﺗﻘﺭﺍﺭﻳﺔ‬

‫ﺍﻟﺗﺩﺭﻳﺟﻲ )‪.(Stepwise Stability Constants‬‬

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‫ﻭﺗﻣﺛﻝ )‪ (n‬ﺃﻗﺻﻰ ﻋﺩﺩ ﺗﻧﺎﺳﻕ ﻷﻳﻭﻥ ﺍﻟﻔﻠﺯ ‪ M‬ﻣﻊ ﺍﻟﻠﻳﻛﺎﻧﺩ ‪ L‬ﻭﻳﺑﻳﻥ ﺍﻟﺷﻛﻝ ﺃﺩﻧﺎﻩ ﺍﻟﻌﻼﻗﺔ ﺑﻳﻥ ﺍﻟﻧﺳﺏ ﺍﻟﻣﺋﻭﻳﺔ ﻟﻛﻝ‬

‫ﻧﻭﻉ ﻣﻥ ﺃﻧﻭﺍﻉ ﺍﻣﻭﻧﻳﺎﺕ ﺍﻟﻧﺣﺎﺱ ﺍﻟﺛﻧﺎﺋﻲ ﻓﻲ ﺍﻟﻣﺣﻠﻭﻝ ﻣﻘﺎﺑﻝ ﺗﺭﻛﻳﺯ ﺍﻻﻣﻭﻧﻳﺎ ﺍﻟﺣﺭﺓ ﻏﻳﺭ ﺍﻟﻣﺗﺣﺩﺓ ﻭ ﻳﺷﻳﺭ ﺍﻟﺭﺳﻡ‬
‫ﺍﻟﺑﻳﺎﻧﻲ ﺍﻟﻰ ﺃﻥ ﺍﻟﻣﻌﻘﺩ ‪ [Cu(NH3)4]+2‬ﻣﻬﻡ ﺟﺩﺍً ﻭ ﺫﻟﻙ ﻻﻧﻪ ﻫﻭ ﺍﻟﻣﺳﻳﻁﺭ ﻓﻲ ﺍﻟﻣﺣﻠﻭﻝ ‪.‬‬

‫• ﻫﻧﺎﻙ ﻁﺭﻳﻘﺔ ﺃﺧﺭﻯ ﻟﻠﺗﻌﺑﻳﺭ ﻋﻥ ﺛﻭﺍﺑﺕ ﺍﻟﺗﻭﺍﺯﻥ ﻭ ﻫﻲ ﻛﺎﻟﺗﺎﻟﻲ‪:‬‬

‫‪M + L ↔ ML‬‬ ‫‪B1‬‬ ‫=‬ ‫]‪[ML‬‬
‫]‪[M ][L‬‬

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‫م‪.‬ﺣﻮراء ﻣﻬﺪي‬ ‫اﻟﻤﺮﺣﻠﺔ اﻟﺜﺎﻟﺜﺔ‬ ‫ﻣﺤﺎﺿﺮات اﻟﻜﻴﻤﻴﺎء اﻟﺘﻨﺎﺳﻘﻴﺔ‬
‫‪M + 2L ↔ ML2‬‬
‫‪B2‬‬ ‫=‬ ‫] ‪[ML2‬‬
‫‪[M ][l]2‬‬

‫‪M + 3L ↔ ML3‬‬ ‫‪B3‬‬ ‫=‬ ‫] ‪[ML3‬‬
‫‪[M ][L]3‬‬

‫‪M + NL ↔ MLN‬‬ ‫‪BN‬‬ ‫=‬ ‫] ‪[MLN‬‬
‫‪[M ][l]N‬‬

‫ﻭ ﺗﺳﻣﻰ ‪ β 1 , β 2 , β 3 , …..‬ﺑﺛﻭﺍﺑﺕ ﺍﻟﺗﻛﻭﻳﻥ ﺍﻟﻛﻠﻲ )ﺛﻭﺍﺑﺕ ﺍﻻﺳﺗﻘﺭﺍﺭ ﺍﻟﻛﻠﻳﺔ(‪.‬‬

‫‪ .‬ﻭ ﺗﺳﻣﻰ ‪ βn‬ﻣﺣﺻﻠﺔ ﺛﻭﺍﺑﺕ ﺍﻻﺳﺗﻘﺭﺍﺭﻳﺔ ﺃﻭ ﺍﻟﺗﻛﻭﻳﻥ‪.‬‬

‫ﻣﻣﺎ ﺳﺑﻕ ﻓﺈﻧﻪ ﻣﻥ ﺍﻟﻭﺍﺿﺢ ﺃﻥ ﻫﻧﺎﻙ ﻋﻼﻗﺔ ﺑﻳﻥ ‪ k‬ﻭ‪ β‬ﻭ ﺑﺎﻟﺗﺎﻟﻲ ﻓﺈﻧﻪ ﻋﻣﻭﻣﺎ ﻳﻛﻭﻥ ‪:‬‬

‫‪Bn = K1K2K3.......Kn‬‬

‫ﻭ ﻫﻛﺫﺍ ﻓﺈﻥ ‪:‬‬

‫ﺛﺎﺑﺕ ﺍﻟﺗﻛﻭﻳﻥ ﺍﻟﻛﻠﻲ ﻟﺗﻛﻭﻳﻥ ﺍﻟﻣﻌﻘﺩ)ﺛﺎﺑﺕ ﺍﻻﺳﺗﻘﺭﺍﺭ ﺍﻟﺛﻳﺭﻣﻭﺩﻳﻧﺎﻣﻳﻛﻲ ﺍﻟﻛﻠﻲ( = ﺣﺎﺻﻝ ﺿﺭﺏ ﺛﻭﺍﺑﺕ‬
‫ﺍﻟﺗﻛﻭﻳﻥ ﺍﻟﺗﺩﺭﻳﺟﻲ‬

‫ﺇﻥ ﺍﻟﺗﻌﻳﻳﻥ ﺍﻟﺩﻗﻳﻕ ﻟﺛﻭﺍﺑﺕ ﺍﻻﺳﺗﻘﺭﺍﺭ ﺍﻟﻣﺗﻛﻭﻧﺔ ﻓﻲ ﺍﻟﻣﺣﻠﻭﻝ ﻣﻭﺿﻭﻉ ﺑﺎﻟﻎ ﺍﻷﻫﻣﻳﺔ ‪ ،‬ﻓﻛﺛﻳﺭ ﻣﻥ ﻁﺭﻕ‬
‫ﺍﻟﻔﺻﻝ ﻭ ﺍﻟﺗﺣﻠﻳﻝ ﺍﻟﻛﻳﻣﻳﺎﺋﻲ ﺇﺿﺎﻓﺔ ﺇﻟﻰ ﺍﻟﻣﺣﺎﻭﻟﺔ ﻟﻠﻭﺻﻭﻝ ﺇﻟﻰ ﻣﺭﻛﺑﺎﺕ ﺛﺎﺑﺗﺔ ﻻﺳﺗﺧﺩﺍﻣﻬﺎ ﻓﻲ ﺷﺗﻰ ﺍﻟﻣﺟﺎﻻﺕ‬

‫ﺍﻟﺻﻧﺎﻋﻳﺔ ﻭ ﺍﻟﺩﻭﺍﺋﻳﺔ‪ ،‬ﺗﺳﺗﻧﺩ ﺇﻟﻰ ﻣﻌﺭﻓﺔ ﺩﻗﻳﻘﺔ ﻟﺛﻭﺍﺑﺕ ﺍﺳﺗﻘﺭﺍﺭ ﺍﻟﻣﻌﻘﺩﺍﺕ ﺍﻟﻣﺗﻛﻭﻧﺔ ﻓﻲ ﺍﻟﻣﺣﻠﻭﻝ‪.‬‬

‫ﻧﻼﺣﻅ ﺃﻧﻪ ﺑﺎﺳﺗﺛﻧﺎءﺍﺕ ﻗﻠﻳﻠﺔ ﻓﺈﻥ ﻗﻳﻡ ‪ Ki،‬ﻋﻠﻰ ﻭﺟﻪ ﺍﻟﻌﻣﻭﻡ ﺗﻘﻝ ﻓﻲ ﺍﻟﺗﻔﺎﻋﻝ ﺍﻟﺗﺩﺭﻳﺟﻲ ﻟﻠﻔﻠﺯ ‪ M‬ﻣﻊ‬

‫ﺍﻟﻠﻳﻛﺎﻧﺩ ‪ . L‬ﻭﻫﺫﺍ ﻳﻣﻛﻥ ﺗﻭﺿﻳﺣﻪ ﻣﻥ ﻗﻳﻡ ‪ Ki،‬ﻟﺗﻛﻭﻳﻥ ﻣﻌﻘﺩﺍﺕ ‪ CdII-NH3‬ﺣﻳﺙ ﺍﻟﻠﻳﻛﺎﻧﺩ ‪ L‬ﻣﺗﻌﺎﺩﻟﺔ ﻭ‬

‫¯‪ CdII-CN‬ﺣﻳﺙ ﺍﻟﻠﻳﻛﺎﻧﺩ ‪ L‬ﺳﺎﻟﺑﺔ ﺍﻟﺷﺣﻧﺔ‪.‬‬ ‫ﻣﻌﻘﺩﺍﺕ‬

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‫م‪.‬ﺣﻮراء ﻣﻬﺪي‬ ‫اﻟﻤﺮﺣﻠﺔ اﻟﺜﺎﻟﺜﺔ‬ ‫ﻣﺤﺎﺿﺮات اﻟﻜﻴﻤﻴﺎء اﻟﺘﻨﺎﺳﻘﻴﺔ‬

‫‪Cd2+ + NH3‬‬ ‫‪↔ [Cd(NH3)]2+‬‬ ‫‪K1= 102.65‬‬

‫‪[Cd(NH3)]2+ + NH3 ↔ [Cd(NH3)2]2+‬‬ ‫‪K2= 102.10‬‬

‫‪[Cd(NH3)2]3+ + NH3 ↔ [Cd(NH3)3]2+‬‬ ‫‪K3= 101.44‬‬
‫‪[Cd(NH3)3]3+ + NH3 ↔ [Cd(NH3)4]2+‬‬ ‫)‪K4= 100.93 ( β4=107.12‬‬

‫‪……………………………………………………………………………………………………..‬‬

‫¯‪Cd2+ + CN‬‬ ‫‪↔ [Cd(CN)]+‬‬ ‫‪K1= 105.48‬‬

‫]‪[Cd(CN)]+ + CN¯ ↔ [Cd(CN)2‬‬ ‫‪K2= 105.12‬‬

‫¯]‪[Cd(CN)2] + CN¯ ↔ [Cd(CN)3‬‬ ‫‪K3= 104.63‬‬
‫¯‪[Cd(CN)3]¯+ CN¯ ↔ [Cd(CN)4]2‬‬ ‫)‪K4= 103.65 ( β4=1018.8‬‬

‫ﻭ ﺍﻟﻘﻳﻡ ﺍﻟﻛﺑﻳﺭﺓ ﻟﺛﻭﺍﺑﺕ ﺍﻻﺳﺗﻘﺭﺍﺭ ﻟﻠﻣﻌﻘﺩ ﺗﺷﻳﺭ ﺇﻟﻰ ﺃﻥ ﺗﺭﻛﻳﺯ ﺍﻟﻣﻌﻘﺩ ﻫﻭ ﺃﻛﺑﺭ ﺑﻛﺛﻳﺭ ﻣﻥ ﺗﺭﻛﻳﺯ ﺍﻟﻣﻛﻭﻧﺎﺕ‬
‫ﺍﻟﺗﻲ ﻳﺗﻛﻭﻥ ﻣﻧﻬﺎ ﺍﻟﻣﻌﻘﺩ ﻋﻧﺩ ﺍﻟﺗﻭﺍﺯﻥ‪ .‬ﻭ ﺗﺳﺟﻝ ﻋﺎﺩﺓ ﺛﻭﺍﺑﺕ ﺍﻻﺳﺗﻘﺭﺍﺭ ﻓﻲ ﺻﻭﺭﺓ ﻟﻭﻏﺎﺭﻳﺗﻡ‪.‬‬

‫ﻭ ﺛﺎﺑﺕ ﺍﻻﺳﺗﻘﺭﺍﺭ ﺍﻟﻛﻠﻲ ﻓﻲ ﺣﺩﻭﺩ ‪ 104‬ﺃﻭ ﺃﻛﺑﺭ ﻳﺷﻳﺭ ﻋﺎﺩﺓ ﺇﻟﻰ ﺗﻛﻭﻳﻥ ﺍﻟﻣﻌﻘﺩ ﺍﻟﺛﺎﺑﺕ ﻣﻥ ﺍﻟﻧﺎﺣﻳﺔ‬
‫ﺍﻟﺛﺭﻣﻭﺩﻳﻧﺎﻣﻳﻛﻳﺔ‪ .‬ﻭ ﻋﻧﺩﻣﺎ ﺗﻛﻭﻥ ﺛﻭﺍﺑﺕ ﺍﻻﺳﺗﻘﺭﺍﺭ ﻭﺍﻁﺋﺔ ﺃﻭ ﺳﺎﻟﺑﺔ ﺍﻟﻘﻳﻣﺔ ﻓﺈﻧﻬﺎ ﺗﺷﻳﺭ ﺇﻟﻰ ﺗﻛﻭﻥ ﺍﻟﻣﻌﻘﺩ‬

‫ﺑﺗﺭﻛﻳﺯ ﻗﻠﻳﻝ ﺟﺩﺍ ﺃﻭ ﻋﺩﻡ ﺗﻛﻭﻧﻪ ‪ ،‬ﻣﺛﺎﻝ‪ :‬ﺗﻛﻭﻳﻥ ])‪ [Cu(NH3)5(OH2‬ﻓﺈﻥ ﻗﻳﻣﺔ ‪ log K5‬ﻫﻲ ‪ 0.5-‬ﺗﻘﺭﻳﺑﺎ‪.‬‬

‫ﻭ ﺃﻣﺎ ﺍﻟﻘﻳﻡ ﺍﻟﻌﺩﺩﻳﺔ ﻟﻬﺫﻩ ﺍﻟﺛﻭﺍﺑﺕ ﻭﻛﻘﺎﻋﺩﺓ ﻋﺎﻣﺔ ﻭ ﻟﻳﺱ ﺇﻁﻼﻗﺎ ﺗﺗﺭﺗﺏ ﺣﺳﺏ ﺍﻟﺗﺭﺗﻳﺏ‪:‬‬

‫‪K1 > K2 > K3 > K4 > Kn‬‬

‫ﺣﻳﺙ ﻳﺯﺩﺍﺩ ﺗﺭﻛﻳﺯ ﺍﻟﻧﻭﺍﺗﺞ ﻛﻠﻣﺎ ﺗﻘﺩﻣﺕ ﺧﻁﻭﺍﺕ ﺍﻟﺗﻔﺎﻋﻝ ‪ ،‬ﻓﺗﻘﻝ ﺑﺎﻟﺗﺎﻟﻲ ﻗﻳﻣﺔ ﺛﺎﺑﺕ ﺍﻟﺗﻛﻭﻳﻥ )ﻧﻅﺭﺍ ﻷﻥ ﺗﺭﻛﻳﺯ‬
‫ﺍﻟﻣﻭﺍﺩ ﺍﻟﺩﺍﺧﻠﺔ ﻓﻲ ﺍﻟﺗﻔﺎﻋﻝ ﺃﻳﺿﺎ ﻛﺑﻳﺭ( ‪.‬‬

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‫م‪.‬ﺣﻮراء ﻣﻬﺪي‬ ‫اﻟﻤﺮﺣﻠﺔ اﻟﺜﺎﻟﺜﺔ‬ ‫ﻣﺤﺎﺿﺮات اﻟﻜﻴﻤﻴﺎء اﻟﺘﻨﺎﺳﻘﻴﺔ‬

‫ﺠـدوﻝ ‪ :١-٦‬اﻋﺘﻤـﺎد ﺜواﺒـت اﻻﺴـﺘﻘ ارر اﻟﺘـدرﻴﺠﻲ )‪log10Kn‬؛ ﺘـدرﻴﺞ ﻤـوﻟﻲ( ﻋﻠـﻰ ﻋـدد اﻟﻤرﺘﺒطـﺎت )‪ (n‬ﻷﻨظﻤـﺔ ﻨﻤوذﺠﻴـﺔ‬
‫)ﻋﻨد ‪ ٢٩٨.٢‬ك(‬

‫‪en /‬‬ ‫‪Cl- /‬‬ ‫‪NCS- /‬‬ ‫‪NH3 /‬‬ ‫‪F- /‬‬ ‫أﻴون اﻟﻔﻠز‪/‬‬
‫‪Fe2+‬‬ ‫‪Pd2+‬‬ ‫‪Cr3+‬‬ ‫‪Co2+‬‬ ‫‪Al3+‬‬ ‫اﻟﻤرﺘﺒط‬

‫‪4.3 1.2‬‬ ‫‪3‬‬ ‫‪2.1 6.1‬‬ ‫‪log10K1‬‬
‫‪3.3 0.5‬‬ ‫‪1.7‬‬ ‫‪1.6 5‬‬ ‫‪log10K2‬‬
‫‪2 -0.3‬‬ ‫‪1‬‬ ‫‪1.1 3.9‬‬ ‫‪log10K3‬‬

‫‪-1.3 0.3‬‬ ‫‪0.7 2.7‬‬ ‫‪log10K4‬‬
‫‪-0.7‬‬ ‫‪0.2 1.6‬‬ ‫‪log10K5‬‬
‫‪-1.3‬‬ ‫‪-0.6 0.5‬‬ ‫‪log10K6‬‬

‫‪H2NCH2CH2NH2 = en‬‬

‫ﻣﺎﺫﺍ ﻳﻌﻧﻲ ﺍﻻﺳﺗﻘﺭﺍﺭ ﻣﻥ ﻧﺎﺣﻳﺔ ﺍﻟﺩﻳﻧﺎﻣﻳﻛﺎ ﺍﻟﺣﺭﺍﺭﻳﺔ ‪.‬‬

‫ﻻﺑﺩ ﻣﻥ ﺗﻭﺿﻳﺢ ﻣﺎﺫﺍ ﻳﻌﻧﻲ ﻋﻠﻡ ﺍﻟﺩﻳﻧﺎﻣﻳﻛﺎ ﺍﻟﺣﺭﺍﺭﻳﺔ ؟‬

‫ﺑﺷﻛﻝ ﻣﺧﺗﺻﺭ" ﻓﺈﻥ ﻋﻠﻡ ﺍﻟﺩﻳﻧﺎﻣﻳﻛﺎ ﺍﻟﺣﺭﺍﺭﻳﺔ ﻳﻧﺑﺊ ﻓﻘﻁ ﻓﻳﻣﺎ ﺇﺫﺍ ﻛﺎﻥ ﺗﻐﻳﺭ ﻛﻳﻣﻳﺎﺋﻲ ﻣﻌﻳﻥ ﻗﺎﺑﻼ ﻟﻠﺣﺩﻭﺙ ﺃﻡ ﻻ ﺩﻭﻥ ﺃﻥ‬
‫ﻳﺑﻳﻥ ﺳﺭﻋﺔ ﺣﺩﻭﺙ ﻫﺫﺍ ﺍﻟﺗﻐﻳﺭ"‪.‬‬

‫ﻓﻳﺳﺗﻁﻳﻊ ﺍﻟﻛﻳﻣﻳﺎﺋﻲ ﺍﺳﺗﻧﺗﺎﺝ ﻓﻳﻣﺎ ﺇﺫﺍ ﻛﺎﻥ ﺗﻔﺎﻋﻝ ﻣﺎ ﻣﻣﻛﻥ ﺍﻟﺣﺩﻭﺙ ﻋﻧﺩ ﻅﺭﻭﻑ ﻣﻌﻳﻧﺔ ﺃﻡ ﻻ‪ .‬ﻭ ﻋﻼﻭﺓ ﻋﻠﻰ ﺫﻟﻙ ﻳﻣﻛﻥ‬
‫ﺃﻥ ﻳﺳﺗﻧﺗﺞ ﺍﻟﻛﻳﻣﻳﺎﺋﻲ ﻓﻳﻣﺎ ﺇﺫﺍ ﻛﺎﻥ ﻣﺭﻛﺏ ﻣﻌﻳﻥ ﺛﺎﺑﺗﺎ ﻋﻧﺩ ﻅﺭﻭﻑ ﻣﻌﻳﻧﺔ ﺃﻡ ﻻ‪..‬‬

‫ﻫﻧﺎﻙ ﻋﻼﻗﺔ ﺗﺭﺑﻁ ﺑﻳﻥ ﺍﻟﺗﻐﻳﺭ ﻓﻲ ﺍﻟﻁﺎﻗﺔ ﺍﻟﺣﺭﺓ ﺍﻟﻘﻳﺎﺳﻳﺔ ‪ ∆G°‬ﻭ ﺛﺎﺑﺕ ﺍﻟﺗﻭﺍﺯﻥ ‪K‬‬

‫‪∆G = ∆H - T∆S‬‬

‫‪ΔG◦ = - RTln β‬‬

‫ﻟﺫﺍ ﻋﻧﺩ ﺩﺭﺍﺳﺔ ﺗﻛﻭﻳﻥ ﺍﻟﻣﺭﻛﺑﺎﺕ ﺍﻟﻣﻌﻘﺩﺓ ﻫﻧﺎﻙ ﻧﻭﻋﺎﻥ ﻣﻥ ﺍﻻﺳﺗﻘﺭﺍﺭﻳﺔ ﻫﻣﺎ‪:‬‬

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‫م‪.‬ﺣﻮراء ﻣﻬﺪي‬ ‫اﻟﻤﺮﺣﻠﺔ اﻟﺜﺎﻟﺜﺔ‬ ‫ﻣﺤﺎﺿﺮات اﻟﻜﻴﻤﻴﺎء اﻟﺘﻨﺎﺳﻘﻴﺔ‬

‫‪ -۱‬ﺍﻻﺳﺗﻘﺭﺍﺭﻳﺔ ﺍﻟﺛﺭﻣﻭﺩﺍﻳﻧﻣﻳﻛﻳﺔ ‪ :Thermodynamic stability‬ﻭﻫﻲ ﻋﺑﺎﺭﺓ ﻋﻥ ﻣﻘﻳﺎﺱ ﻣﺩﻯ ﺗﻛﻭﻥ ﻣﺭﻛﺏ ﻣﻌﻳﻥ ﺃﻭ‬
‫ﻣﺩﻯ ﺗﺣﻭﻟﻪ ﺍﻟﻰ ﻣﺭﻛﺏ ﺍﺧﺭﻋﻧﺩ ﻅﺭﻭﻑ ﻣﻌﻳﻧﺔ ﻭ ﻓﻲ ﺣﺎﻟﺔ ﺍﻟﺗﻭﺍﺯﻥ ‪ ،‬ﻭﻳﻌﻧﻲ ﺗﻬﺗﻡ ﺑﺛﻭﺍﺑﺕ ﺍﻟﺗﻛﻭﻳﻥ ﻟﻠﻣﻌﻘﺩﺍﺕ ﻭ ﻁﺎﻗﺎﺕ‬

‫ﺍﺻﺭﺓ ﻓﻠﺯ‪ -‬ﻟﻳﻛﺎﻧﺩ ﻭﻏﻳﺭﻫﺎ‪.‬‬
‫‪ -۲‬ﺍﻻﺳﻘﺭﺍﺭﻳﺔ ﺍﻟﺣﺭﻛﻳﺔ ‪ : Kinetic stability‬ﻳﺷﻳﺭ ﻫﺫﺍ ﺍﻟﻧﻭﻉ ﻣﻥ ﺍﻻﺳﺗﻘﺭﺍﺭﻳﺔ ﺇﻟﻰ ﺳﺭﻋﺔ ﺑﻠﻭﻍ ﺣﺎﻟﺔ ﺍﻟﺗﻭﺍﺯﻥ ﺍﺛﻧﺎء‬
‫ﺗﻛﻭﻥ ﻣﺭﻛﺏ ﻣﻌﻳﻥ ﺍﻭ ﺗﺣﻭﻟﻪ ﺍﻟﻰ ﻣﺭﻛﺏ ﺍﺧﺭ ‪ ،‬ﻭﻳﻌﻧﻲ ﺇﻧﻬﺎ ﺗﻬﺗﻡ ﺑﻣﻌﺩﻝ ﺳﺭﻋﺔ ﺍﻟﺗﻔﺎﻋﻼﺕ ﺍﻟﻛﻳﻣﻳﺎﺋﻳﺔ ﻭ ﻣﻳﻛﺎﻧﻳﻛﻳﺔ‬

‫ﺍﻟﺗﻔﺎﻋﻼﺕ ﺍﻟﻛﻳﻣﻳﺎﺋﻳﺔ ‪.‬‬

‫ﻣﺛﺎﻝ‪ :‬ﻓﻲ ﺍﺣﺩﻯ ﺍﻟﺗﺟﺎﺭﺏ ﺍﻟﺗﻲ ﺃﺟﺭﻳﺕ ﻋﻠﻰ ﺗﻔﺎﻋﻝ ‪ [Ni(H2O)6]2+‬ﻣﻊ ﻣﺣﻠﻭﻝ ﺍﻻﻣﻭﻧﻳﺎ ﻋﻧﺩ ﺩﺭﺟﺔ ﺣﺭﺍﺭﺓ ‪ 30‬ﻣﺋﻭﻳﺔ ﺗﻡ‬

‫ﺍﻟﺣﺻﻭﻝ ﺛﻭﺍﺑﺕ ﺍﻻﺳﺗﻘﺭﺍﺭﻳﺔ ﺍﻟﻣﺗﻌﺎﻗﺑﺔ ﺍﻟﺗﺎﻟﻳﺔ ) ﺑﺩﻻﻟﺔ ﺍﻟﻠﻭﻏﺎﺭﻳﺗﻡ (‪:‬‬

‫‪logK1‬‬ ‫‪LogK2‬‬ ‫‪LogK3‬‬ ‫‪LogK4‬‬ ‫‪logK6‬‬ ‫‪logK6‬‬

‫‪2.67 2.12 1.61 1.07 0.63 -0.09‬‬

‫‪ -۱‬ﻟﻣﺎﺫﺍ ﺗﺗﻧﺎﻗﺹ ﻗﻳﻡ ‪ Kn‬ﺍﻟﻣﺗﻌﺎﻗﺑﺔ ‪ -۲ .‬ﻣﺎ ﻫﻭ ﻣﺩﻟﻭﻝ ﺍﻟﻘﻳﻣﺔ ﺍﻟﺳﺎﻟﺑﺔ ﻟﺛﺎﺑﺕ ﺍﻟﺗﻛﻭﻳﻥ ‪. K6‬‬

‫‪ -٤‬ﻣﺎ ﻫﻲ ﺍﻟﻔﺻﺎﺋﻝ ﺍﻷﻳﻭﻧﻳﺔ ﺍﻟﻣﺷﻣﻭﻟﺔ ﺑﺎﻟﺗﻭﺍﺯﻥ ﺍﻟﺫﻱ ﻳﺻﺎﺣﺏ ‪ K3‬ﻭ ‪K4‬‬ ‫‪ -۲‬ﻣﺎ ﻗﻳﻣﺔ ﺛﺎﺑﺕ ﺍﻟﺗﻛﻭﻳﻥ ﺍﻟﻛﻠﻲ ‪B‬‬

‫‪Ni2+ + 4NH3‬‬ ‫‪[ Ni(NH3)4]2+‬‬ ‫‪-٥‬ﻣﺎ ﻣﻘﺩﺍﺭ ﺍﻟﺗﺑﺩﻝ ﻓﻲ ﺍﻟﻁﺎﻗﺔ ﺍﻟﺣﺭﺓ ﺍﻟﻘﻳﺎﺳﻲ ﻟﻠﺗﻔﺎﻋﻝ ‪:‬‬

‫ﺍﻟﺟﻭﺍﺏ‪ -۱ :‬ﺃﺳﻬﺎﻡ ﻛﻝ ﻣﻥ ﺍﻟﻌﻭﺍﻣﻝ ﺍﻹﺣﺻﺎﺋﻳﺔ ﻭ ﺍﻟﻔﺭﺍﻏﻳﺔ ) ﺍﻟﺧﺎﺻﺔ ﺑﺎﻹﻋﺎﻗﺔ ( ﻓﻲ ﺗﻐﻳﺭﺍﺕ ﺍﻻﻧﺗﺭﻭﺑﻲ ﻭ ﻫﺫﻩ ﺍﻟﺗﻐﻳﺭﺍﺕ‬
‫ﻫﻲ ﺍﻟﺳﺑﺏ ﺍﻟﺭﺋﻳﺳﻲ ﻓﻲ ﺗﻐﻳﺭ ﻗﻳﻡ ‪ Kn‬ﺍﻟﻣﺗﻌﺎﻗﺑﺔ ‪.‬‬

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‫م‪.‬ﺣﻮراء ﻣﻬﺪي‬ ‫اﻟﻤﺮﺣﻠﺔ اﻟﺜﺎﻟﺜﺔ‬ ‫ﻣﺤﺎﺿﺮات اﻟﻜﻴﻤﻴﺎء اﻟﺘﻨﺎﺳﻘﻴﺔ‬

‫‪ -۲‬ﺍﻟﻣﻌﻘﺩ ‪ [Ni(NH3)5(H2O)]+2‬ﻫﻭ ﺍﻟﻣﺣﺑﺫ ﺛﺭﻣﻭﺩﻳﻧﺎﻣﻳﻛﻳﺎً ﻋﻠﻰ ﺍﻟﻣﻌﻘﺩ ‪. [Ni(NH3)6]+2‬‬

‫‪[Ni(H2O)4(NH3)2]+2 + NH3‬‬ ‫‪[Ni(H2O)3(NH3)3]+2 + H2O‬‬ ‫‪ -۳‬ﻗﻳﻣﺔ ‪.B = 8.01‬‬
‫‪[Ni(H2O)3(NH3)3]+2 + NH3‬‬ ‫‪[Ni(H2O)2(NH3)4]+2 + H2O‬‬ ‫‪ -٤‬ﺍﻟﺗﻭﺍﺯﻥ ﺍﻟﺫﻱ ﻳﺻﺎﺣﺏ ‪ K3‬ﻫﻭ ‪:‬‬
‫ﺍﻟﺗﻭﺍﺯﻥ ﺍﻟﺫﻱ ﻳﺻﺎﺣﺏ ‪ K4‬ﻫﻭ ‪:‬‬

‫‪ΔG◦ = - RTln β4 = -2.303 X 1.987 X 7.47 = -10.36 Kcal mol-1‬‬ ‫‪-٥‬‬

‫ﺍﻟﻌﻭﺍﻣﻝ ﺍﻟﻣﺅﺛﺭﺓ ﻓﻲ ﺍﺳﺗﻘﺭﺍﺭ ﺍﻟﻣﻌﻘﺩﺍﺕ‪:‬‬

‫ﺗﺗﺣﻛﻡ ﻋﺩﺓ ﻋﻭﺍﻣﻝ ﻓﻲ ﺍﺳﺗﻘﺭﺍﺭ ﻣﻌﻘﺩ ﻳﺗﻛﻭﻥ ﻣﻥ ﺍﻳﻭﻥ ﻓﻠﺯﻱ ﻭ ﻟﻳﻛﺎﻧﺩ ﻣﻌﻳﻧﻳﻥ‪.‬‬

‫ﺃﻭﻻ ‪ :‬ﺻﻔﺎﺕ ﺍﻟﻔﻠﺯ‪.‬‬

‫ﺍﺳﺗﻘﺭﺍﺭﻳﺔ ﺍﻟﻣﻌﻘﺩﺍﺕ ﺍﻟﺗﻲ ﺗﻛﻭﻧﻬﺎ ﺍﻟﻔﻠﺯﺍﺕ ﺍﻟﻣﺧﺗﻠﻔﺔ ﺗﺧﺿﻊ ﻻﺗﺟﺎﻫﺎﺕ ﻣﻌﻳﻧﺔ ﺍﻟﺗﻲ ﺗﺷﻣﻝ ﺗﺄﺛﻳﺭﺍﺕ ﺣﺟﻡ ﺍﻻﻳﻭﻥ ﺍﻟﻔﻠﺯﻱ ﻭ‬
‫ﺷﺣﻧﺗﻪ ﻓﻣﺛﻼً ‪ -۱‬ﻓﻔﻲ ﺣﺎﻟﺔ ﺍﻻﻳﻭﻧﺎﺕ ﺍﻟﻔﻠﺯﻳﺔ ﺫﺍﺕ ﺍﻟﺷﺣﻧﺔ ﺍﻟﻣﺗﺳﺎﻭﻳﺔ ﻭ ﺍﻟﺣﺟﻡ ﺍﻟﻣﺧﺗﻠﻑ ﻳﻼﺣﻅ ﺃﻥ ﺍﻻﻳﻭﻧﺎﺕ ﺫﺍﺕ ﺍﻟﺣﺟﻡ‬

‫ﺍﻷﺻﻐﺭ ﺗﻭﻟﺩ ﻣﺟﺎﻻً ﻛﻬﺭﺑﺎﺋﻳﺎً ﺍﻛﺑﺭ ﻭﺑﺎﻟﺗﺎﻟﻲ ﻓﻬﻲ ﺗﻛﻭﻥ ﻣﺭﻛﺑﺎﺕ ﺃﻛﺛﺭ ﺍﺳﺗﻘﺭﺍﺭﺍً ‪،‬ﻛﻣﺎ ﺍﻻﻳﻭﻧﺎﺕ ﺍﻟﺗﺎﻟﻳﺔ‪:‬‬

‫‪BeOH+ MgOH+ CaOH+ SrOH+ BaOH+‬‬ ‫ﺍﺯﺩﻳﺎﺩ ﺣﺟﻡ ﺍﻻﻳﻭﻥ ﺍﻟﻔﻠﺯﻱ‬
‫ﻧﻘﺻﺎﻥ ﺍﺳﺗﻘﺭﺍﺭﻳﺔ ﺍﻟﻣﻌﻘﺩﺍﺕ‬

‫ﻧﻘﺻﺎﻥ ﻗﻳﻡ ‪K‬‬

‫‪ -۲‬ﺃﻣﺎ ﻓﻲ ﺣﺎﻟﺔ ﺍﻻﻳﻭﻧﺎﺕ ﺫﺍﺕ ﺍﻟﺣﺟﻡ ﺍﻟﻣﺗﺳﺎﻭﻱ ﺗﻘﺭﻳﺑﺎً ﻭ ﺍﻟﺷﺣﻧﺎﺕ ﺍﻟﻣﺧﺗﻠﻔﺔ ‪ ،‬ﻓﻼﻳﻭﻥ ﺫﻭ ﺍﻟﺷﺣﻧﺔ ﺍﻷﻛﺑﺭ ﻳﺳﻠﻁ ﻣﺟﺎﻻً ﺃﻛﺑﺭ‬
‫ﻭ ﺑﺎﻟﺗﺎﻟﻲ ﺗﻛﻭﻥ ﻣﺭﻛﺑﺎﺕ ﺃﻛﺛﺭ ﺍﺳﺗﻘﺭﺍﺭﺍً‪.‬‬

‫ﺃﺫﻥ ﻧﺳﺑﺔ ﺍﻟﺷﺣﻧﺔ ﺇﻟﻰ ﻧﺻﻑ ﺍﻟﻘﻁﺭ ﻋﻼﻗﺔ ﻣﻬﻣﺔ ﻓﻲ ﺗﻘﺭﻳﺭ ﺍﺳﺗﻘﺭﺍﺭﻳﺔ ﺍﻟﻣﺭﻛﺑﺎﺕ ﺍﻟﻣﻌﻘﺩﺓ ‪ ،‬ﻟﻧﺄﺧﺫ ﻋﻠﻰ ﺳﺑﻳﻝ ﺍﻟﻣﺛﺎﻝ ﺍﻳﻭﻧﺎﺕ‬
‫‪ M2+‬ﻟﻠﺳﻠﺳﻠﺔ ﺍﻻﻧﺗﻘﺎﻟﻲ ﺍﻷﻭﻟﻰ )ﻧﺻﻑ ﺍﻟﻘﻁﺭ ﻳﻘﻝ ﻋﺑﺭ ﺍﻟﺳﻠﺳﻠﺔ ( ﻭ ﺑﻬﺫﺍ ﻓﺄﻥ ﺍﻟﻧﺳﺑﺔ ]ﺷﺣﻧﺔ \ ﻧﺻﻑ ﺍﻟﻘﻁﺭ[ ﺗﺯﺩﺍﺩ ﻋﺑﺭ‬
‫ﺍﻟﺳﻠﺳﻠﺔ ﻭﺑﺎﻟﺗﺎﻟﻲ ﺗﺯﺩﺍﺩ ﺍﺳﺗﻘﺭﺍﺭﻳﺔ ﺍﻟﻣﺭﻛﺑﺎﺕ ﺍﻟﻣﻌﻘﺩﺓ ﺍﻟﻧﺎﺗﺟﺔ ‪ ،‬ﻭ ﻳﻌﺭﻑ ﻫﺫﺍ ﺍﻟﺗﺭﺗﻳﺏ ﺑﺳﻠﺳﻠﺔ ﺍﻳﺭﻓﻧﻙ – ﻭ ﻟﻳﺎﻣﺱ‬

‫)‪. (Irving – Williams‬‬

‫‪Mn+2 < Fe+2 < Co+2 < Ni+2 < Cu+2 > Zn+2‬‬

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‫م‪.‬ﺣﻮراء ﻣﻬﺪي‬ ‫اﻟﻤﺮﺣﻠﺔ اﻟﺜﺎﻟﺜﺔ‬ ‫ﻣﺤﺎﺿﺮات اﻟﻜﻴﻤﻴﺎء اﻟﺘﻨﺎﺳﻘﻴﺔ‬

‫ﻭﻗﺩ ﺃﺗﺿﺢ ﺫﻟﻙ ﻣﻥ ﺩﺭﺍﺳﺔ ﺍﺳﺗﻘﺭﺍﺭ ﺍﻟﻣﻌﻘﺩﺍﺕ ﺍﻟﻣﺗﻛﻭﻧﺔ ﺑﻳﻥ ﺍﻷﻳﻭﻧﺎﺕ ﺍﻟﻣﺳﺗﻘﺭﺓ ﺛﻧﺎﺋﻳﺔ ﺍﻟﺗﻛﺎﻓﺅ ) ﺃﻱ ﻣﻥ ﺍﻟﻣﻧﻐﻧﻳﺯ‬
‫ﻓﺻﺎﻋﺩﺍً( ﻭ ﺑﻳﻥ ﻣﺎ ﻳﺭﺑﻭ ﻋﻠﻰ ‪ ۹۰‬ﻟﻳﻛﺎﻧﺩ ﺗﺭﺗﺑﻁ ﺑﺎﻟﻔﻠﺯ ﺑﻭﺍﺳﻁﺔ ﺫﺭﺓ ﺍﻻﻭﻛﺳﺟﻳﻥ ﺃﻭ ﺍﻟﻧﺗﺭﻭﺟﻳﻥ‪ ،‬ﺇﻥ ﺍﺳﺗﻘﺭﺍﺭ ﻣﻌﻘﺩﺍﺕ ﻫﺫﻩ‬

‫ﺍﻻﻳﻭﻧﺎﺕ ﻳﺗﻐﻳﺭ ﻛﻣﺎ ﻓﻲ ﺃﻋﻼﻩ ﻣﻬﻣﺎ ﻛﺎﻥ ﻧﻭﻉ ﺍﻟﻠﻳﻛﺎﻧﺩ‪.‬‬

‫‪ -۳‬ﺗﺄﺛﻳﺭ ﺍﻟﻣﺟﺎﻝ ﺍﻟﺑﻠﻭﺭﻱ ‪(Crystal field effect):‬‬
‫ﺗﻠﻌﺏ ﻁﺎﻗﺔ ﺍﻻﺳﺗﻘﺭﺍﺭ ﻟﻠﻣﺟﺎﻝ ﺍﻟﺑﻠﻭﺭﻱ )‪ ( CFSE‬ﺩﻭﺭﺍً ﻣﻬﻣﺎً ﻓﻲ ﺍﺳﺗﻘﺭﺍﺭﻳﺔ ﻣﻌﻘﺩﺍﺕ ﺍﻟﻔﻠﺯﺍﺕ ﺍﻻﻧﺗﻘﺎﻟﻳﺔ ﻭﻳﻅﻬﺭ ﺃﻧﻬﺎ‬

‫ﺍﻟﻣﺳﺅﻭﻟﺔ ﻋﻥ ﺍﻟﻧﻅﺎﻡ ﺍﻟﻁﺑﻳﻌﻲ ﻻﺳﺗﻘﺭﺍﺭﻳﺔ ﻣﻌﻘﺩﺍﺕ ﺍﻟﺳﻠﺳﻠﺔ ﺍﻻﻧﺗﻘﺎﻟﻳﺔ ﺍﻷﻭﻟﻰ ‪.‬‬

‫ﺛﺎﻧﻳﺎ ‪ :‬ﺧﻭﺍﺹ ﺍﻟﻠﻳﻛﺎﻧﺩ‪:‬‬

‫‪ .۱‬ﻁﺑﻳﻌﺔ ﺫﺭﺓ ﺍﻟﻠﻳﻛﺎﻧﺩ ‪:‬‬

‫ﺗﻌﻭﺩ ﺍﻟﺫﺭﺍﺕ ﺍﻟﺗﻲ ﺗﺭﺗﺑﻁ ﻣﺑﺎﺷﺭﺓ ﺑﺄﻳﻭﻧﺎﺕ ﺍﻟﻔﻠﺯﺍﺕ ﻓﻲ ﻣﻌﻘﺩﺍﺗﻬﺎ ﺇﻟﻰ ﺍﻟﻌﻧﺎﺻﺭ ﺍﻟﺗﻲ ﻟﻬﺎ ﻛﻬﺭﻭﺳﺎﻟﺑﻳﺔ ﻋﺎﻟﻳﺔ ﺃﻱ ﺍﻟﺗﻲ ﺗﻘﻊ ﻓﻲ‬
‫ﺍﻟﺟﻬﺔ ﺍﻟﻳﻣﻧﻰ ﻣﻥ ﺍﻟﺟﺩﻭﻝ ﺍﻟﺩﻭﺭﻱ ﻭﻫﻲ‪:‬‬

‫‪, I , Br , Cl , F , Te , Se , S , O , Sb , C , N , As , P‬‬

‫ﻭ ﻟﻛﻝ ﻣﻥ ﻫﺫﻩ ﺍﻟﺫﺭﺍﺕ ﺇﻥ ﻭﺟﺩﺕ ﻓﻲ ﺟﺭﻳﺋﺔ ﺃﻭ ﺃﻳﻭﻥ ﻟﻳﻛﺎﻧﺩ‪ ،‬ﻗﺎﺑﻠﻳﺔ ﺍﻟﺗﻧﺎﺳﻕ ﻣﻊ ﺃﻳﻭﻥ ﻓﻠﺯ‪ .‬ﻭ ﻟﻘﺩ ﻭﺟﺩ ﻓﻲ ﺣﺎﻟﺔ ﺍﻟﻬﺎﻟﻭﺟﻳﻧﺎﺕ‬
‫‪،‬ﺃﻥ ﺍﺳﺗﻘﺭﺍﺭ ﺍﻟﻣﻌﻘﺩﺍﺕ ﺍﻟﻣﺗﻛﻭﻧﺔ ﻣﻥ ﺍﺗﺣﺎﺩ ﺍﻟﻬﺎﻟﻳﺩ ﻭ ﻏﺎﻟﺑﻳﺔ ﺍﻟﻔﻠﺯﺍﺕ ﻳﺗﺑﻊ ﺍﻟﺗﺳﻠﺳﻝ ﺍﻟﺗﺎﻟﻲ‪:‬‬

‫‾‪F‾ > Cl‾ > Br‾ > I‬‬

‫ﻭ ﻳﺻﺑﺢ ﻫﺫﺍ ﺍﻟﺗﺳﻠﺳﻝ ﻣﻌﻛﻭﺳﺎ ﻓﻲ ﺣﺎﻟﺔ ﺑﻌﺽ ﺍﻟﻔﻠﺯﺍﺕ ﺍﻟﺗﻲ ﺗﺷﻣﻝ ‪:‬‬
‫‪Hg2+ , Ag1+ , Cu1+ , Pt 2+‬‬

‫ﻭﻟﻘﺩ ﺗﻡ ﺗﺻﻧﻳﻑ ﺍﻟﻔﻠﺯﺍﺕ ﻭﻓﻘﺎً ﻟﺧﺻﺎﺋﺹ ﺍﻟﺗﻘﺑﻝ ﻟﻠﻣﺯﺩﻭﺝ ﺍﻻﻟﻛﺗﺭﻭﻧﻲ ﻣﻥ ﻗﺑﻝ ﺍﻟﻠﻳﻛﺎﻧﺩ ﺇﻟﻰ ﺛﻼﺛﺔ ﺃﺻﻧﺎﻑ ‪ :‬ﺍﻟﺻﻧﻑ ‪ a‬ﻭ‬
‫ﺍﻟﺻﻧﻑ ‪ b‬ﻭ ﺻﻧﻑ ﻭﺳﻁﻲ ﻣﺎﺑﻳﻥ ﺍﻻﺛﻧﻳﻥ )ﻣﺑﺩﺃ ﺑﻳﺭﺳﻭﻥ(ﻛﻣﺎ ﻓﻲ ﺍﻟﺟﺩﻭﻝ ﺍﻟﺗﺎﻟﻲ ‪:‬‬

‫ﺍﻟﺻﻧﻑ ‪(soft acid) b‬‬ ‫ﺍﻟﺻﻧﻑ ﺍﻟﻭﺳﻁﻲ‬ ‫ﺍﻟﺻﻧﻑ ‪(hard acid) a‬‬
‫‪Hg2+ Ag+‬‬ ‫‪Fe+2,Co+2‬‬ ‫‪Ca+2 U4+ Th4+ Zr4+ Sc3+ Be2+‬‬

‫‪(Pt2+ Pd2+)c‬‬ ‫‪Ni+2,Cu+2‬‬ ‫‪Co+3,Ti+4, Y3+ Fe3+ Cr3+ Sn4+‬‬

‫‪Cu+,Au+,Pt+4‬‬ ‫‪Zn+2,Pb+2 Al+3,Mn+2 Ac3+ Ce3+ La3+ Mg2+‬‬

‫‪ -‬ﻓﻠﺯﺍﺕ ﺍﻟﺻﻧﻑ ‪) a‬ﺍﻟﻔﻠﺯﺍﺕ ﺫﺍﺕ ﺍﻟﻛﻬﺭﻭﻣﻭﺟﺑﻳﺔ ﺍﻟﻌﺎﻟﻳﺔ ( ﺗﻛﻭﻥ ﻣﻌﻘﺩﺍﺕ ﻣﺳﺗﻘﺭﺓ ﻣﻊ ﻟﻳﻛﺎﻧﺩﺍﺕ ﺗﻌﻭﺩ ﺫﺭﺍﺗﻬﺎ‬
‫ﺍﻟﻭﺍﻫﺑﺔ ﺍﻟﻰ ﺍﻟﺩﻭﺭﺓ ﺍﻟﺛﺎﻧﻳﺔ ﻣﻥ ﺍﻟﺟﺩﻭﻝ ﺍﻟﺩﻭﺭﻱ )‪ (F, O, N‬ﻭﺃﻟﻔﺔ ﻫﺫﻩ ﺍﻟﻔﻠﺯﺍﺕ ﻟﻬﺫﺍ ﺍﻟﻧﻭﻉ ﻣﻥ ﺍﻟﻠﻳﻛﺎﻧﺩﺍﺕ‬

‫‪64‬‬

‫م‪.‬ﺣﻮراء ﻣﻬﺪي‬ ‫اﻟﻤﺮﺣﻠﺔ اﻟﺜﺎﻟﺜﺔ‬ ‫ﻣﺤﺎﺿﺮات اﻟﻜﻴﻤﻴﺎء اﻟﺘﻨﺎﺳﻘﻴﺔ‬

‫ﻳﺗﻧﺎﺳﺏ ﻣﻊ ﺍﻟﺻﻔﺎﺕ ﺍﻟﻘﺎﻋﺩﻳﺔ ﻟﻠﻳﻛﺎﻧﺩ ‪ ،‬ﻓﺗﺯﺩﺍﺩ ﺍﺳﺗﻘﺭﺍﺭﻳﺔ ﺍﻟﻣﻌﻘﺩﺍﺕ ﺑﺎﺯﺩﻳﺎﺩ ﻗﺎﻋﺩﻳﺔ ﺍﻟﻠﻳﻛﺎﻧﺩ ‪ ،‬ﻓﻣﺛﻼَ ﺗﺗﻧﺎﻗﺹ‬
‫ﻗﺎﻋﺩﻳﺔ ﺍﻟﻠﻳﻛﺎﻧﺩﺍﺕ ﺍﻻﺗﻳﺔ ﻭ ﻛﺫﻟﻙ ﺍﺳﺗﻘﺭﺍﺭﻳﺔ ﺍﻟﻣﻌﻘﺩﺍﺕ ﺍﻟﺗﻲ ﺗﻛﻭﻧﻬﺎ ‪:‬‬

‫‪NH3 > RNH2> R2NH >R3N‬‬
‫‪H2O > ROH > R2O‬‬

‫‪ -‬ﺑﻳﻧﻣﺎ ﻓﻠﺯﺍﺕ ﺍﻟﺻﻧﻑ ‪ b‬ﺗﻛﻭﻥ ﻣﻌﻘﺩﺍﺕ ﺃﻛﺛﺭ ﺍﺳﺗﻘﺭﺍﺭﺍً ﻣﻊ ﻟﻳﻛﺎﻧﺩﺍﺕ ﺗﻌﻭﺩ ﺫﺭﺍﺗﻬﺎ ﺍﻟﻭﺍﻫﺑﺔ ﺇﻟﻰ ﺍﻟﺩﻭﺭﺓ ﺍﻟﺛﺎﻟﺛﺔ ﺃﻭ‬
‫ﺍﻟﺩﻭﺭﺍﺕ ﺍﻟﻼﺣﻘﺔ ﻓﻲ ﺍﻟﺟﺩﻭﻝ ﺍﻟﺩﻭﺭﻱ ‪.‬‬

‫‪ .۲‬ﺍﻟﻘﺩﺭﺓ ﻋﻠﻰ ﺗﻛﻭﻳﻥ ﺍﻟﻛﻼﺑﻳﺎﺕ )‪:(chelation‬‬

‫ﺍﻟﻣﻌﻘﺩ ﺍﻟﻛﻠﻳﺗﻲ ﻫﻭ ﺫﻟﻙ ﺍﻟﻣﻌﻘﺩ ﺍﻟﺫﻱ ﻳﻛﻭﻥ ﻓﻳﻪ ﺍﻟﻔﻠﺯ ﻣﺗﺂﺻﺭ ﻣﻊ ﻟﻳﻛﺎﻧﺩﺍﺕ ﺛﻧﺎﺋﻳﺔ ﺍﻟﺳﻥ )ﺃﻭ ﺃﻛﺛﺭ( ﻓﻲ ﻧﻅﺎﻡ ﺣﻠﻘﻲ‪.‬‬

‫ﻭ ﻳﺷﻳﺭ ﻣﺻﻁﻠﺢ " ﺍﻟﺗﺄﺛﻳﺭ ﺍﻟﻛﻠﻳﺗﻲ" ﺇﻟﻰ ﺍﻻﺳﺗﻘﺭﺍﺭﻳﺔ ﺍﻟﻌﺎﻟﻳﺔ ﻟﻠﻣﻌﻘﺩ ﺍﻟﻛﻠﻳﺗﻲ )ﺑﺣﻳﺙ ﻳ ّﻛﻭﻥ ﻣﻌﻬﺎ ﺣﻠﻘﺎﺕ ﺳﺩﺍﺳﻳﺔ ﺃﻭ‬
‫ﺧﻣﺎﺳﻳﺔ ﺍﻟﺫﺭﺍﺕ( ﺑﺎﻟﻣﻘﺎﺭﻧﺔ ﺇﻟﻰ ﺍﺳﺗﻘﺭﺍﺭﻳﺔ ﺍﻟﻣﻌﻘﺩ ﺍﻟﻣﺗﺂﺻﺭ ﻓﻳﻪ ﺍﻟﻔﻠﺯ ﻣﻊ ﻧﻔﺱ ﺍﻟﻌﺩﺩ ﻭ ﺍﻟﻧﻭﻉ ﻣﻥ ﻟﻳﻛﺎﻧﺩﺍﺕ ﺃﺣﺎﺩﻳﺔ ﺍﻟﺳﻥ‪.‬‬

‫ﻣﺛﺎﻝ ﻟﺫﻟﻙ‪ :‬ﺍﻋﺗﺑﺭ ﺛﻭﺍﺑﺕ ﺍﻻﺳﺗﻘﺭﺍﺭ ﺍﻟﻛﻠﻲ ﻟﺗﻛﻭﻳﻥ ﺍﻟﻣﻌﻘﺩﺍﺕ ﺍﻻﺗﻳﺔ‪:‬‬

‫)‪Cu2+(aq.) + 4NH3(aq.) ↔ [Cu(NH3)4]2+(aq.‬‬ ‫‪log K = 11.9‬‬

‫)‪Cu2+(aq.) + 2en (aq.) ↔ [Cu(en)2]2+ (aq.‬‬ ‫‪log K = 20.0‬‬

‫)‪Cu2+(aq.) + trien (aq.) ↔ [Cu(trien)]2+ (aq.‬‬ ‫‪log K = 20.5‬‬

‫ﻭ ﻛﻠﻣﺎ ﺍﺯﺩﺍﺩ ﻋﺩﺩ ﺍﻟﺣﻠﻘﺎﺕ ﺍﻟﻛﻳﻠﻳﺗﻳﺔ ﻳﺻﺑﺢ ﺍﻟﻣﺭﻛﺏ ﺍﻟﻣﻌﻘﺩ ﺃﻛﺛﺭ ﺍﺳﺗﻘﺭﺍﺭﺍً ‪ ،‬ﺣﻳﺙ ﻳﺻﺎﺣﺏ ﻫﺫﺍ ﺗﻐﻳﺭ ﻣﻭﺟﺏ ﻓﻲ ﺍﻻﻧﺗﺭﻭﺑﻲ‪.‬‬

‫ﻭ ﻟﻔﻬﻡ ﻫﺫﺍ ﺍﻟﺗﺄﺛﻳﺭ ﻓﺈﻧﻧﺎ ﻻﺑﺩ ﺃﻥ ﻧﻠﺟﺄ ﺇﻟﻰ ﺍﻟﻌﻼﻗﺎﺕ ﺍﻟﺛﺭﻣﻭﺩﻳﻧﺎﻣﻳﻛﻳﺔ ﺍﻵﺗﻳﺔ‪:‬‬
‫‪ΔG◦ = - RTln β‬‬

‫◦‪ΔG◦ = ΔH◦ - TΔS‬‬

‫ﻭ ﻫﻛﺫﺍ ﻧﺳﺗﻁﻳﻊ ﺃﻥ ﻧﻼﺣﻅ ﺃﻥ ﺛﺎﺑﺕ ﺍﻻﺳﺗﻘﺭﺍﺭ ﺍﻟﻛﻠﻲ ﻟﺗﻛﻭﻳﻥ ﺍﻟﻣﻌﻘﺩ ﻳﻌﺗﻣﺩ ﻋﻠﻰ ﺍﻟﻁﺎﻗﺔ ﺍﻟﺣﺭﺓ ﺍﻟﻘﻳﺎﺳﻳﺔ ◦‪ ΔG‬ﺍﻟﺗﻲ ﻫﻲ ﻣﺣﺻﻠﺔ‬
‫ﺗﻐﻳﺭﺍﺕ ﺍﻻﻧﺛﺎﻟﺑﻲ ﻭ ﺍﻻﻧﺗﺭﻭﺑﻲ ﻓﻲ ﻋﻣﻠﻳﺔ ﺗﻛﻭﻳﻥ ﺍﻟﻣﻌﻘﺩ‪.‬‬

‫ﻣﺛــــــــــــــــﺎﻝ‪:‬‬

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‫م‪.‬ﺣﻮراء ﻣﻬﺪي‬ ‫اﻟﻤﺮﺣﻠﺔ اﻟﺜﺎﻟﺜﺔ‬ ‫ﻣﺤﺎﺿﺮات اﻟﻜﻴﻤﻴﺎء اﻟﺘﻨﺎﺳﻘﻴﺔ‬

‫ﻧﻌﺗﺑﺭ ﻋﻠﻰ ﺳﺑﻳﻝ ﺍﻟﻣﺛﺎﻝ ﻗﻳﻡ ◦‪ ΔS◦، ΔH◦ ، ΔG‬ﻟﻠﺗﻔﺎﻋﻠﻳﻥ ﺍﻵﺗﻳﻳﻥ‪:‬‬

‫)‪Cd2+(aq.) + 4CH3NH2(aq.) ↔ [Cd(CH3NH2)4]2+(aq.‬‬ ‫‪log β = 6.52‬‬

‫‪Cd2+(aq.) + 2H2NCH2CH2NH2(aq.) ↔ [Cd(en)2]2+(aq.) log β = 10.6‬‬

‫)‪ΔH◦(kJmol-1‬‬ ‫)‪ΔS◦(Jmol-1deg-1) -TΔS◦(kJmol-1) ΔG◦(kJmol-1‬‬

‫‪-57.3‬‬ ‫‪-67.3‬‬ ‫‪20.1 -37.2‬‬

‫‪-56.5‬‬ ‫‪+14.1‬‬ ‫‪-4.2 -60.7‬‬

‫ﻓﻲ ﻫﺫﺍ ﺍﻟﻣﺛﺎﻝ ﻧﺟﺩ ﺃﻥ ﺍﻟﺗﻐﻳﺭ ﻓﻲ ﺍﻻﻧﺛﺎﻟﺑﻲ ﺍﻟﻘﻳﺎﺳﻲ ◦‪ ΔH‬ﻟﻛﻝ ﻣﻥ ﺗﻛﻭﻥ ﻭﺍﺣﺩ ﻣﻭﻝ ﻣﻥ ﺍﻟﻣﻌﻘﺩ ﺍﻷﻭﻝ )ﻏﻳﺭ ﺍﻟﻛﻠﻳﺗﻲ( ﻭ ﺍﻟﻣﻌﻘﺩ‬
‫ﺍﻟﺛﺎﻧﻲ )ﺍﻟﻛﻠﻳﺗﻲ( ﻳﻛﻭﻥ ﻣﺗﺳﺎﻭﻱ ﻓﻲ ﺣﺩﻭﺩ ﺍﻟﺧﻁﺄ ﺍﻟﺗﺟﺭﻳﺑﻲ‪ .‬ﻭ ﺑﺎﻟﺗﺎﻟﻲ ﻓﺈﻥ ﺍﻹﺳﺗﻘﺭﺍﺭﻳﺔ ﺍﻟﻌﺎﻟﻳﺔ ﻟﻠﻣﻌﻘﺩ ﺍﻟﺛﺎﻧﻲ )◦‪ ΔG‬ﺃﻛﺛﺭ‬
‫ﺳﺎﻟﺑﻳﺔ ﻭ ﺑﺎﻟﺗﺎﻟﻲ ‪ log β‬ﺃﻋﻠﻰ ﻭ ﺗﻛﻣﻥ ﻓﻲ ﺍﻟﺗﻐﻳﺭ ﻓﻲ ﺍﻻﻧﺗﺭﻭﺑﻲ ◦‪ ΔS‬ﺣﻳﺙ ﺃﻥ ﺗﻛﻭﻳﻥ ﺍﻟﻣﻌﻘﺩ ﺍﻟﻛﻠﻳﺗﻲ ﻳﺻﺎﺣﺑﻪ ﺗﻐﻳﺭ ﻣﻭﺟﺏ ﻓﻲ‬
‫ﺍﻻﻧﺗﺭﻭﺑﻲ )ﺃﻱ ﺯﻳﺎﺩﺓ ﺍﻻﻧﺗﺭﻭﺑﻲ( ﻣﻣﺎ ﻳﺟﻌﻝ ﺍﻟﺣﺩ ﺍﻻﻧﺗﺭﻭﺑﻲ ◦‪ -TΔS‬ﺳﺎﻟﺏ ﺍﻟﻘﻳﻣﺔ ‪ ،‬ﺑﻳﻧﻣﺎ ﺗﻛﻭﻳﻥ ﺍﻟﻣﻌﻘﺩ ﺍﻟﻼﻛﻠﻳﺗﻲ ﻳﺻﺎﺣﺑﻪ‬

‫ﻧﻘﺻﺎﻥ ﻓﻲ ﺍﻻﻧﺗﺭﻭﺑﻲ ﻓﻳﻘﺎﻝ ﺃﻥ ﺍﻟﻣﻌﻘﺩ ﺍﻟﻛﻠﻳﺗﻲ ﺃﻛﺛﺭ ﺍﺳﺗﻘﺭﺍﺭﻳﺔ ﻣﻥ ﺍﻟﻣﻌﻘﺩ ﺍﻟﻼﻛﻠﻳﺗﻲ ﺍﻟﻣﺣﺗﻭﻱ ﻋﻠﻰ ﻧﻔﺱ ﻧﻭﻉ ﻭ ﻋﺩﺩ ﺍﻟﺫﺭﺍﺕ‬

‫ﺍﻟﻭﺍﻫﺑﺔ ﺑﺳﺑﺏ ﺍﻟﺗﺄﺛﻳﺭ ﺍﻟﻛﻠﻳﺗﻲ ﺍﻟﺫﻱ ﻫﻭ ﻧﺗﻳﺟﺔ ﺍﻟﺯﻳﺎﺩﺓ ﻓﻲ ﻗﻳﻣﺔ ﺍﻻﻧﺗﺭﻭﺑﻲ ﺍﻟﻣﺻﺎﺣﺏ ﻟﺗﻛﻭﻳﻥ ﺍﻟﻣﻌﻘﺩ ﺍﻟﻛﻠﻳﺗﻲ‪.‬‬

‫ﻣﺛـــــــــــــــــــﺎﻝ ﺁﺧﺭ ‪ :‬ﻓﻲ ﺗﻔﺎﻋﻝ ﺍﺳﺗﺑﺩﺍﻝ ﻟﻳﻛﺎﻧﺩ ﺛﻧﺎﺋﻲ ﺍﻟﺳﻥ ﺑﻠﻳﻛﺎﻧﺩ ﺃﺣﺎﺩﻱ ﺍﻟﺳﻥ ﻣﺛﻝ ‪:‬‬
‫‪[Ni(NH3)6]2+(aq.) + 3en(aq.) ↔ [Ni(en)3]2+(aq.) + 6NH3 log K = 9.67‬‬

‫ﻋﻧﺩ ﺍﻟﺗﻭﺍﺯﻥ ﻧﺟﺩ ﺃﻥ ﺍﻟﺗﻔﺎﻋﻝ ﻗﺩ ﺃﺗﺟﻪ ﺇﻟﻰ ﺗﻛﻭﻳﻥ ﺍﻟﻣﻌﻘﺩ ﺍﻟﻛﻠﻳﺗﻲ ‪ [Ni(en)3]2+‬ﻋﻠﻰ ﺣﺳﺎﺏ ﺍﻟﻣﻌﻘﺩ ﺍﻟﻼﻛﻠﻳﺗﻲ ﺍﻷﻗﻝ ﺍﺳﺗﻘﺭﺍﺭﻳﺔ‬
‫ﺣﻳﺙ ﺃﻥ ﺛﺎﺑﺕ ﺍﻹﺳﺗﻘﺭﺍﺭ ﻟﻬﺫﺍ ﺍﻟﺗﻔﺎﻋﻝ ﻋﺎﻟﻲ ‪ .‬ﻭ ﻫﺫﺍ ﺃﻳﺿﺎ ﺑﺳﺑﺏ ﺍﻟﺗﺄﺛﻳﺭ ﺍﻟﻛﻠﻳﺗﻲ ﺍﻟﺫﻱ ﻫﻭ ﻧﺗﻳﺟﺔ ﺯﻳﺎﺩﺓ ﺍﻻﻧﺗﺭﻭﺑﻲ ﺍﻟﻣﺻﺎﺣﺏ‬

‫ﻟﻬﺫﺍ ﺍﻟﺗﻔﺎﻋﻝ ‪ .‬ﻓﺭﻏﻡ ﺃﻥ ﻫﺫﺍ ﺍﻟﺗﻔﺎﻋﻝ ﺻﺎﺣﺑﻪ ﺗﻐﻳﺭ ﻓﻲ ﺍﻻﻧﺛﺎﻟﺑﻲ‬
‫‪ ΔH◦ =-12.1 kJ1mol‬ﻣﻘﺩﺍﺭﺍ ﻣﺅﺛﺭ ﻓﻲ ﻗﻳﻣﺔ ◦‪ ΔG‬ﺍﻟﺳﺎﻟﺑﺔ ﻭ ﺑﺎﻟﺗﺎﻟﻲ ‪ log K‬ﺍﻟﻌﺎﻟﻳﺔ ‪.‬‬

‫ﻛﻣﺎ ﺃﻥ ﺗﻛﻭﻥ ﺍﻟﻣﻌﻘﺩﺍﺕ ﺍﻟﻣﺧﻠﺑﻳﺔ ﺃﻛﺛﺭ ﺍﺳﺗﻘﺭﺍﺭﺍ‪ ،‬ﺃﺫﺍ ﻛﺎﻧﺕ ﺗﺣﺗﻭﻱ ﻋﻠﻰ ﺭﻭﺍﺑﻁ ﺃﺣﺎﺩﻳﺔ ﻭ ﺛﻧﺎﺋﻳﺔ ﻣﺗﺗﺎﻟﻳﺔ‪ ،‬ﻭ ﺗﺗﻣﺭﻛﺯ ﺍﻟﻛﺛﺎﻓﺔ‬

‫ﺍﻻﻟﻛﺗﺭﻭﻧﻳﺔ ﻣﻥ ﺍﻟﻧﻭﻉ ‪ π‬ﻭ ﺗﻧﺗﺷﺭ ﻓﻭﻕ ﻛﻝ ﺍﻟﺣﻠﻘﺎﺕ ‪ ،‬ﻭ ﻫﺫﺍ ﻳﺳﺑﺏ ﺍﺳﺗﻘﺭﺍﺭﻳﺔ ﺃﻛﺛﺭ ﺗﻌﺭﻑ ﺑﺎﻟﺭﻧﻳﻥ‪ ،‬ﻭ ﻣﻥ ﺃﻣﺛﻠﺔ ﺫﻟﻙ ﺍﻻﺳﺗﻳﻝ‬
‫ﺍﺳﻳﺗﻭﻥ ﻣﻊ ﺍﻟﻔﻠﺯﺍﺕ ‪.‬‬

‫ﻭ ﻫﻛﺫﺍ ﻧﺳﺗﻁﻳﻊ ﺃﻥ ﻧﻼﺣﻅ ﺃﻥ ﺛﺎﺑﺕ ﺍﻻﺳﺗﻘﺭﺍﺭ ﺍﻟﻛﻠﻲ ﻟﺗﻛﻭﻳﻥ ﺍﻟﻣﻌﻘﺩ ﻳﻌﺗﻣﺩ ﻋﻠﻰ ﺍﻟﺗﻐﻳﺭﺍﺕ ﺍﻟﻛﺑﻳﺭﺓ ﻓﻲ ﺍﻻﻧﺗﺭﻭﺑﻲ ﻓﻲ ﻋﻣﻠﻳﺔ‬
‫ﺗﻛﻭﻳﻥ ﺍﻟﻣﻌﻘﺩ‪.‬‬

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‫م‪.‬ﺣﻮراء ﻣﻬﺪي‬ ‫اﻟﻤﺮﺣﻠﺔ اﻟﺜﺎﻟﺜﺔ‬ ‫ﻣﺤﺎﺿﺮات اﻟﻜﻴﻤﻴﺎء اﻟﺘﻨﺎﺳﻘﻴﺔ‬

‫ﻣﻳﻛﺎﻧﻳﻛﻳﺔ ﺗﻔﺎﻋﻼﺕ ﺍﻟﻣﺭﻛﺑﺎﺕ ﺍﻟﻣﻌﻘﺩﺓ ‪-:‬‬
‫‪Mechanisms of reactions of complex compounds:‬‬

‫ﺍﻟﻣﻳﻛﺎﻧﻳﻛﻳﺔ ) ﻣﺳﺎﺭ ﺍﻟﺗﻔﺎﻋﻝ ( ﻭﻫﻭ ﺍﻟﻁﺭﻳﻕ ﺍﻟﺫﻱ ﺗﺳﻠﻛﻪ ﺍﻟﺫﺭﺍﺕ ﻭ ﺍﻻﻳﻭﻧﺎﺕ ﻓﻲ ﺗﻔﺎﻋﻠﻬﺎ ﻣﻊ ﺑﻌﺿﻬﺎ ﺍﻟﺑﻌﺽ ﺑﻧﻅﺎﻡ‬
‫ﻣﻌﻳﻥ ﻟﻠﺣﺻﻭﻝ ﻋﻠﻰ ﺍﻟﺟﺯﻱء ﻓﻲ ﺻﻭﺭﺗﻪ ﺍﻷﺧﻳﺭﺓ ‪.‬‬

‫ﺇﻥ ﺗﻔﺎﻋﻼﺕ ﺍﻟﺗﻌﻭﻳﺽ ) ﺍﻹﺣﻼﻝ( ﺍﻟﺗﻲ ﺃﺟﺭﻳﺕ ﻋﻠﻰ ﻣﻌﻘﺩﺍﺕ ﺍﻟﻔﻠﺯﺍﺕ ﺍﻻﻧﺗﻘﺎﻟﻳﺔ ﻫﻲ ﻣﻥ ﺃﻛﺛﺭ ﺍﻟﺗﻔﺎﻋﻼﺕ ﺍﻟﺗﻲ ﺗﻣﺕ‬
‫ﺩﺭﺍﺳﺗﻬﺎ ﻣﻥ ﺍﻟﻧﺎﺣﻳﺗﻳﻥ ﺍﻟﺣﺭﻛﻳﺔ ﻭ ﺍﻟﻣﻳﻛﺎﻧﻳﻛﻳﺔ ‪ ،‬ﻭ ﺍﻟﻣﺭﻛﺑﺎﺕ ﺍﻟﺗﻲ ﺗﻣﺕ ﺩﺭﺍﺳﺗﻬﺎ ﺑﺻﻭﺭﺓ ﺷﺎﻣﻠﺔ ﻫﻲ ﺍﻟﻣﻌﻘﺩﺍﺕ ﺛﻣﺎﻧﻳﺔ‬

‫ﺍﻟﺳﻁﻭﺡ‪.‬‬
‫ﺗﺻﻧﻑ ﺍﻟﻣﻌﻘﺩﺍﺕ ﺍﻟﺗﻲ ﻳﺗﻡ ﺗﻔﺎﻋﻝ ﺍﻹﺣﻼﻝ ﻓﻳﻬﺎ ﺑﺳﺭﻋﺔ ﺑﺄﻧﻬﺎ ﻣﻌﻘﺩﺍﺕ ﻓﻌﺎﻟﺔ ‪ labile‬ﺃﻱ ﺇﻥ ﻣﻌﺩﻝ ﺳﺭﻋﺔ ﻫﺫﻩ‬
‫ﺍﻟﺗﻔﺎﻋﻼﺕ ﺳﺭﻳﻊ ﺟﺩﺍً) ﻋﻣﺭ ﺍﻟﻧﺻﻑ ﻟﻪ ﻳﻛﻭﻥ ﺍﻗﻝ ﻣﻥ ﺩﻗﻳﻘﺔ ½‪ ، ( t‬ﺃﻣﺎ ﺍﻟﻣﻌﻘﺩﺍﺕ ﺍﻟﺗﻲ ﺗﺣﺻﻝ ﻓﻳﻬﺎ ﺗﻔﺎﻋﻼﺕ‬
‫ﺍﻟﺗﻌﻭﻳﺽ ﺑﺻﻭﺭﺓ ﺑﻁﻳﺋﺔ ﺟﺩﺍً ﻓﺗﺻﻧﻑ ﺑﻛﻭﻧﻬﺎ ﺧﺎﻣﻠﺔ ‪) inert‬ﻋﻣﺭ ﺍﻟﻧﺻﻑ ﻟﻪ ﻳﻛﻭﻥ ﺍﻛﺑﺭ ﻣﻥ ﺩﻗﻳﻘﺔ( ‪ ،‬ﻳﺟﺏ ﻋﺩﻡ‬
‫ﺍﻟﻣﺯﺝ ﺑﻳﻥ ﺍﺳﺗﻌﻣﺎﻝ ﻣﺻﻁﻠﺢ ﻣﺳﺗﻘﺭ ﻭ ﻣﺻﻁﻠﺢ ﺧﺎﻣﻝ ) ‪ ( stable, inert‬ﻭ ﻣﺻﻁﻠﺢ ﻏﻳﺭ ﻣﺳﺗﻘﺭ ﻭ ﻣﺻﻁﻠﺢ ﻓﻌﺎﻝ‬
‫) ‪ ( instable , labile‬ﻓﻭﻓﻘﺎً ﻟﻠﻣﻔﻬﻭﻡ ﺍﻟﺛﺭﻣﻭﺩﺍﻧﻳﻣﻳﻛﻲ ﻳﻔﺿﻝ ﺍﺳﺗﻌﻣﺎﻝ ﻣﺻﻁﻠﺣﻲ ) ﻣﺳﺗﻘﺭ ﻭ ﻏﻳﺭ ﻣﺳﺗﻘﺭ ( ‪،‬‬

‫ﻭﻭﻓﻘﺎً ﻟﻠﻣﻔﻬﻭﻡ ﺍﻟﺣﺭﻛﻲ ﻳﻔﺿﻝ ﺍﺳﺗﻌﻣﺎﻝ ﻣﺻﻁﻠﺣﻲ)ﺧﺎﻣﻝ ﻭ ﻓﻌﺎﻝ ( ‪.‬‬
‫ﻟﻘﺩ ﺃﺷﺎﺭ ﺗﻭﺏ ‪ Taube‬ﺇﻟﻰ ﻭﺟﻭﺩ ﻋﻼﻗﺔ ﻣﻬﻣﺔ ﺑﻳﻥ ﺍﻟﺗﺭﻛﻳﺏ ﺍﻻﻟﻛﺗﺭﻭﻧﻲ ﻭ ﻣﻌﺩﻝ ﺳﺭﻋﺔ ﺍﻟﺗﻔﺎﻋﻼﺕ ﺍﻟﻛﻳﻣﻳﺎﺋﻳﺔ‬
‫ﻟﻣﻌﻘﺩﺍﺕ ﺍﻻﻭﺭﺑﻳﺗﺎﻝ ﺍﻟﺩﺍﺧﻠﻲ ﻭﺗﺻﻧﻑ ﺍﻟﻣﻌﻘﺩﺍﺕ ﺳﺩﺍﺳﻳﺔ ﺍﻟﺗﻧﺎﺳﻕ ﺍﺳﺗﻧﺎﺩﺍً ﺇﻟﻰ ﻋﺩﺩ ﺍﻟﻛﺗﺭﻭﻧﺎﺕ ‪ d‬ﺍﻟﻣﻭﺟﻭﺩﺓ ﻓﻲ ﺍﻟﺫﺭﺓ‬

‫ﺍﻟﻣﺭﻛﺯﻳﺔ ﻟﻠﻣﻌﻘﺩ ﻭ ﻛﻣﺎ ﻳﻠﻲ ‪:‬‬

‫ﺍﻟﻣﻌﻘﺩﺍﺕ ﺍﻟﻔﻌﺎﻟﺔ )‪:(Labile Complexes‬‬

‫‪ ‬ﺟﻣﻳﻊ ﺍﻟﻣﻌﻘﺩﺍﺕ ﺍﻟﺗﻲ ﺗﻛﻭﻥ ﻓﻳﻬﺎ ﺫﺭﺓ ﺍﻟﻔﻠﺯ ﺍﻟﻣﺭﻛﺯﻱ ﺗﺣﻭﻱ ﻋﻠﻰ ﺍﻟﻛﺗﺭﻭﻧﺎﺕ ‪ d‬ﻓﻲ ﺍﻭﺭﺑﻳﺗــــــــــــــــﺎﻻﺕ ‪ ) eg‬ﻭﻫﻲ‬
‫‪ ( dz2,dx2-y2‬ﻭﺍﻷﻣﺛﻠﺔ ﻣﺑﻳﻧﺔ ﻓﻲ ﺟﺩﻭﻝ ﺍﻟﺗﺭﻛﻳﺏ ﺍﻻﻟﻛﺗﺭﻭﻧﻲ ‪.‬‬

‫‪ ‬ﻭ ﺃﻳﺿﺎً ﺗﻛﻭﻥ ﺍﻟﻣﻌﻘﺩﺍﺕ ﻓﻌﺎﻟﺔ ﺇﺫﺍ ﺍﺣﺗﻭﺕ ﺍﻭﺭﺑﻳﺗﺎﻻﺕ ‪ t2g‬ﻋﻠﻰ ﺍﻗﻝ ﻣﻥ ﺛﻼﺛﺔ ﺍﻟﻛﺗﺭﻭﻧﺎﺕ ﻓﻲ ﺍﻭﺭﺑﻳﺗﺎﻻﺕ ‪. d‬‬

‫ﺍﻟﻣﻌﻘﺩﺍﺕ ﺍﻟﺧﺎﻣﻠﺔ )‪: (Inert Complexes‬‬
‫‪ ‬ﻭﺗﺷﻣﻝ ﻣﻌﻘﺩﺍﺕ ‪ d3‬ﺍﻟﺛﻣﺎﻧﻳﺔ ﺍﻟﺳﻁﻭﺡ ﻳﺿﺎﻑ ﻟﻬﺎ ﺍﻟﻣﻌﻘﺩﺍﺕ ‪ d4, d5 , d6‬ﺫﺍﺕ ﺍﻟﺑﺭﻡ ﺍﻟﻭﺍﻁﺊ ﺑﻣﻌﻧﻰ ﺃﺧﺭ ﺍﺣﺗﻭﺍء‬

‫ﺍﻭﺭﺑﻳﺗﺎﻻﺕ ‪ t2g‬ﻋﻠﻰ ﺍﻟﻛﺗﺭﻭﻧﺎﺕ ﺃﻣﺎ ﺑﺻﻭﺭﺓ ﺟﺯﺋﻳﺔ ﺃﻭ ﻣﻛﺗﻣﻠﺔ ‪.‬‬

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‫م‪.‬ﺣﻮراء ﻣﻬﺪي‬ ‫اﻟﻤﺮﺣﻠﺔ اﻟﺜﺎﻟﺜﺔ‬ ‫ﻣﺤﺎﺿﺮات اﻟﻜﻴﻤﻴﺎء اﻟﺘﻨﺎﺳﻘﻴﺔ‬

‫�ﺪول اﻟﱰ�ﻴﺐ �ﻟﻜﱰوﱐ ﳌﻌﻘﺪات �ورﺑيتﺎل ا�ا�ﲇ اﳋﺎﻣ� و اﻟﻔﻌﺎ�‬

‫ﺍﻟﺗﺭﻛﻳﺏ ﺍﻻﻟﻛﺗﺭﻭﻧﻲ‬ ‫ﺍﻻﻳﻭﻥ ﺍﻟﻔﻠﺯﻱ ﺍﻟﻣﺭﻛﺯﻱ) ﺍﻟﻣﻌﻘﺩﺍﺕ ﺍﻟﻔﻌﺎﻟﺔ(‬
‫‪t2g0 eg0‬‬ ‫‪Sc(III) , Ti(IV) ,Zr(IV) ,Hf(IV) ,Ce(IV) ,Th(IV) ,Nb(V) ,‬‬
‫)‪Mo(IV), Ca(II‬‬
‫‪t2g1 eg0‬‬ ‫)‪Ti(III) , V(IV) , Mo(V) , W(V) , Re(VI‬‬
‫‪t2g2 eg0‬‬ ‫)‪Ti(II) , V(III) , Nb(III) , Ta(III) , W(IV) , Re(V), Ru(VI‬‬

‫ﺍﻟﺗﺭﻛﻳﺏ ﺍﻻﻟﻛﺗﺭﻭﻧﻲ‬ ‫ﺍﻻﻳﻭﻥ ﺍﻟﻔﻠﺯﻱ ﺍﻟﻣﺭﻛﺯﻱ) ﺍﻟﻣﻌﻘﺩﺍﺕ ﺍﻟﺧﺎﻣﻠﺔ(‬
‫‪t2g3 eg0‬‬ ‫)‪V(II) , Cr(III) , Mo(III) , W(III) , Mn(IV) ,Re(IV‬‬
‫)‪Cr(CN)64- , Mn(CN)6-3 , Re(III) , Ru(IV) , Os(IV‬‬
‫‪t2g4 eg0‬‬ ‫)‪Mn(CN)64- ,Re(II) , Fe(CN)63- , Fe(Phen)33+ , Ru(III‬‬
‫‪t2g5 ego‬‬
‫‪t2g6 eg0‬‬ ‫‪Fe(CN)64- , Fe(phen)32+ , Ru(II) , Co(III)(except CoF63-),‬‬
‫)‪Rh(III‬‬

‫ﻭ ﻳﺗﺿﺢ ﺃﻫﻣﻳﺔ ﻫﺫﺍ ﺍﻟﺗﺻﻧﻳﻑ ﻣﻥ ﺍﻟﺗﻣﻳﻳﺯ ﺍﻟﻭﺍﺿﺢ ﺑﻳﻥ ﻣﻌﻘﺩ ﻓﻌﺎﻝ ﻭ ﺃﺧﺭ ﺧﺎﻣﻝ ﻟﻧﻔﺱ ﺍﻳﻭﻥ ﺍﻟﻔﻠﺯ ﻓﻲ ﺣﺎﻟﺗﻲ ﺗﺄﻛﺳﺩ ﻣﺧﺗﻠﻔﺗﻳﻥ‬

‫ﻭﻧﺣﻥ ﻧﻌﺭﻑ ﺃﻥ ﺍﻻﺳﺗﻘﺭﺍﺭﻳﺔ ﺗﺯﺩﺍﺩ ﺑﺯﻳﺎﺩﺓ ﺣﺎﻟﺔ ﺍﻟﺗﺄﻛﺳﺩ ﻟﻠﻔﻠﺯ ‪ ،‬ﻭﻟﻛﻥ ﻧﺟﺩ ﺍﻥ ﺍﻳﻭﻧﻲ ‪ Mo+3‬ﻭ ‪ W+3‬ﺿﻣﻥ ﺍﻟﻣﻌﻘﺩﺍﺕ ﺍﻟﺧﺎﻣﻠﺔ‬
‫ﻭ ﺍﻳﻭﻧﺎﺕ ﺣﺎﻻﺕ ﺍﻟﺗﺄﻛﺳﺩ ﺍﻷﻋﻠﻰ ‪ W+4 , W+5 , W+6 , Mo+6 , Mo+5 , Mo+4 ,‬ﺿﻣﻥ ﺍﻟﻣﻌﻘﺩﺍﺕ ﺍﻟﻔﻌﺎﻟﺔ ‪ ،‬ﻭ ﻳﻣﻛﻥ ﺗﻔﺳﻳﺭ‬
‫ﺃﺫﺍ ﻋﻠﻣﻧﺎ ﺃﻥ ﻣﻌﺩﻝ ﺳﺭﻋﺔ ﺗﻔﺎﻋﻝ ﺍﻟﺗﻌﻭﻳﺽ ﻳﻌﺗﻣﺩ ﻋﻠﻰ ﺗﻭﻓﻳﺭ ﺍﻭﺭﺑﻳﺗﺎﻝ ﺷﺎﻏﺭ ﻻﺳﺗﻘﺑﺎﻝ ﺍﻟﻣﺟﻣﻭﻋﺔ ﺍﻟﻣﻬﺎﺟﻣﺔ ﻛﻣﺎ ﺳﻳﻭﺿﺢ‬

‫ﻓﻲ ﻣﻳﻛﺎﻧﻳﻛﻳﺔ ﺗﻔﺎﻋﻼﺕ ﺍﻹﺣﻼﻝ ﺃﺩﻧﺎﻩ ‪.‬‬

‫ﻣﻳﻛﺎﻧﻳﻛﻳﺔ ﺗﻔﺎﻋﻼﺕ ﺍﻹﺣﻼﻝ )‪: (Mechanisms of Substation Reactions‬‬

‫ﺑﺎﻟﻧﺳﺑﺔ ﻟﺗﻔﺎﻋﻼﺕ ﺍﻹﺣﻼﻝ ﻳﻭﺟﺩ ﻧﻭﻋﺎﻥ ﺃﺳﺎﺳﻳﺎﻥ ﻣﻥ ﺍﻟﻣﻳﻛﺎﻧﻳﻛﻳﺔ ‪ :‬ﻁﺭﻕ ﺍﻟﺗﻔﻛﻙ ﻭ ﻁﺭﻕ ﺍﻹﺣﻼﻝ ‪ ،‬ﻭﺑﺷﻛﻝ ﻋﺎﻡ ﻧﺳﺗﻁﻳﻊ‬
‫ﺃﻥ ﻧﺑﻳﻥ ﻫﺫﻳﻥ ﺍﻟﻧﻭﻋﻳﻥ ﻣﻥ ﺍﻟﻣﻳﻛﺎﻧﻳﻛﻳﺔ ﻓﻲ ﺗﻔﺎﻋﻝ ﺍﻹﺣﻼﻝ ﻟﺛﻣﺎﻧﻲ ﺍﻟﺳﻁﻭﺡ ‪.‬‬

‫‪ ‬ﻣﻳﻛﺎﻧﻳﻛﻳﺔ ﺍﻟﺗﻔﻛﻙ )‪ ( SN1‬ﻭ ﺗﻌﻧﻲ ﺃﺣﻼﻝ ﻧﻳﻛﻠﻳﻭﻓﻳﻠﻲ ﺃﺣﺎﺩﻱ ﺍﻟﺟﺯﻱء ‪ ،‬ﻭﻳﺳﻣﻰ ﺍﻟﺗﻔﺎﻋﻝ ﻧﻳﻛﻠﻳﻭﻓﻳﻠﻲ ﻷﻥ ﺍﻟﻠﻳﻛﺎﻧﺩ ﺍﻟﻘﺎﺩﻡ‬
‫ﻳﺑﺣﺙ ﻋﻥ ﻣﺭﻛﺯ ﻣﻭﺟﺏ ﺍﻟﺷﺣﻧﺔ ﻭ ﻫﻭ ﺍﻳﻭﻥ ﺍﻟﻔﻠﺯ ﻭﺗﺗﺿﻣﻥ ﻫﺫﻩ ﺍﻟﻣﻳﻛﺎﻧﻳﻛﻳﺔ ﻋﻣﻠﻳﺔ ﺗﺣﻠﻝ ﺃﺣﺎﺩﻳﺔ ﺍﻟﺟﺯﻳﺋﺔ ) ﺗﻣﺛﻝ‬
‫ﺍﻟﺧﻁﻭﺓ ﺍﻟﻣﻘﺭﺭﺓ ﻟﻣﻌﺩﻝ ﺳﺭﻋﺔ ﺍﻟﺗﻔﺎﻋﻝ ( ﻣﺅﺩﻳﺔ ﺍﻟﻰ ﺗﻛﻭﻳﻥ ﻣﻌﻘﺩ ﻭﺳﻁﻲ ﺃﻭ ﺣﺎﻟﺔ ﺍﻧﺗﻘﺎﻝ ﺫﺍﺕ ﺗﻧﺎﺳﻕ ﺧﻣﺎﺳﻲ ﻭ ﻳﻠﻲ‬
‫ﻫﺫﻩ ﺍﻟﺧﻁﻭﺓ ﺗﻔﺎﻋﻝ ﺳﺭﻳﻊ ﺑﻳﻥ ﺍﻟﻣﻌﻘﺩ ﺍﻟﻭﺳﻁﻲ ﻭ ﺍﻟﻣﺟﻣﻭﻋﺔ ﺍﻟﻣﻬﺎﺟﻣﺔ ‪ .‬ﻭﻳﺗﻡ ﻓﻳﻬﺎ ﺍﻻﺳﺗﺑﺩﺍﻝ ﺣﺳﺏ ﺍﻟﻣﻌﺎﺩﻻﺕ‬

‫ﺍﻟﺗﺎﻟﻳﺔ ‪:‬‬

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‫م‪.‬ﺣﻮراء ﻣﻬﺪي‬ ‫اﻟﻤﺮﺣﻠﺔ اﻟﺜﺎﻟﺜﺔ‬ ‫ﻣﺤﺎﺿﺮات اﻟﻜﻴﻤﻴﺎء اﻟﺘﻨﺎﺳﻘﻴﺔ‬

‫‪M L5X‬‬ ‫‪k1‬‬ ‫‪ML5 + X‬‬ ‫]‪r = k1 [ML5X‬‬
‫‪slow‬‬ ‫‪+Y‬‬
‫‪k2‬‬ ‫ﺗﻛﻭﻳﻥ ﺃﺻﺭﺓ ‪M-Y‬‬
‫‪fast‬‬ ‫‪M L5Y‬‬
‫‪Y‬‬
‫ﻛﺳﺭ ﺃﺻﺭﺓ ‪L M-X‬‬ ‫‪LL‬‬
‫‪LX‬‬ ‫‪+Y M‬‬

‫‪M -X‬‬ ‫‪LL‬‬
‫‪L‬‬
‫‪LL‬‬ ‫ﻣﺭﻛﺏ ﻭﺳﻁﻲ ﺧﻣﺎﺳﻲ ﺍﻟﺗﻧﺎﺳﻕ‬
‫‪L‬‬

‫ﻭﻣﻌﺩﻝ ﺳﺭﻋﺔ ﺍﻟﺗﻔﺎﻋﻝ ﻳﻌﺗﻣﺩ ﻋﻠﻰ ﻣﺎﺩﺓ ﻣﺗﻔﺎﻋﻠﺔ ﻭﺍﺣﺩﺓ ﻓﻘﻁ ‪ ،‬ﺃﻱ ﻳﻌﺗﻣﺩ ﻋﻠﻰ ﺗﺭﻛﻳﺯ ﺍﻻﻳﻭﻥ ﺍﻟﻣﺗﻣﻳﺊ ﻟﻠﻔﻠﺯ ﻭﻻ ﻳﻌﺗﻣﺩ ﻋﻠﻰ‬
‫ﺗﺭﻛﻳﺯ ﺍﻟﻠﻳﻛﺎﻧﺩ ﺍﻟﺩﺍﺧﻝ ‪ ،‬ﻭ ﻗﺎﻧﻭﻥ ﻣﻌﺩﻝ ﺳﺭﻋﺔ ﺍﻟﺗﻔﺎﻋﻝ ﻳﻣﻛﻥ ﺗﻣﺛﻳﻠﻪ ﻛﻣﺎ ﻳﺄﺗﻲ ‪:‬‬

‫]‪Rate = K [ML5X‬‬

‫ﻭﻗﺩ ﻻﺣﻅ ‪ Taube‬ﻧﻘﺻﺎﻥ ﻓﻲ ﻣﻌﺩﻝ ﺳﺭﻋﺔ ﺗﻔﺎﻋﻼﺕ ﺍﻟﺗﺣﻠﻝ ﺍﻟﻣﺎﺋﻲ ﻭﺫﻟﻙ ﺑﺎﺯﺩﻳﺎﺩ ﺷﺣﻧﺔ ﺍﻻﻳﻭﻥ ﺍﻟﻣﺭﻛﺯﻱ ﻋﻠﻰ ﻁﻭﻝ ﺳﻠﺳﻠﺔ‬
‫ﺍﻻﻳﻭﻧﺎﺕ ‪:‬‬

‫ﺃﺩﺕ ﻫﺫﻩ ﺍﻟﻣﻼﺣﻅﺔ ﺇﻟﻰ ﺍﻗﺗﺭﺍﺡ ﻣﻳﻛﺎﻧﻳﻛﻳﺔ ‪ SN1‬ﻟﻬﺫﻩ ﺍﻟﺗﻔﺎﻋﻼﺕ ‪ ،‬ﻭ ﺗﻌﺗﺑﺭ ﻣﻌﻘﺩﺍﺕ ﺍﻟﻛﻭﺑﻠﺕ ﺍﻟﺛﻼﺛﻲ ﺍﻷﻳﻭﻧﻳﺔ ﺃﻛﺛﺭ‬
‫ﺍﻟﻣﺭﻛﺑﺎﺕ ﺍﻟﺗﻲ ﺩﺭﺳﺕ ﺑﺷﻛﻝ ﻭﺍﺳﻊ ﻻﺳﺗﻘﺭﺍﺭﻫﺎ ﻭﺳﻬﻭﻟﺔ ﺗﺣﺿﻳﺭﻫﺎ ﻭ ﺗﻔﺎﻋﻼﺗﻬﺎ ﺍﻟﺑﻁﻳﺋﺔ ﺟﻌﻠﻬﺎ ﺳﻬﻠﺔ ﻟﻠﺩﺭﺍﺳﺔ ﺍﻟﺣﺭﻛﻳﺔ‬

‫ﺑﺷﻛﻝ ﺧﺎﺹ‬

‫‪ ‬ﻣﻳﻛﺎﻧﻳﻛﻳﺔ ‪ SN2‬ﺍﻥ ﺍﻟﺧﻁﻭﺓ ﺍﻟﻣﺣﺩﺩﺓ ﻟﻣﻌﺩﻝ ﺳﺭﻋﺔ ﺍﻟﺗﻔﺎﻋﻝ ﺗﺗﺿﻣﻥ ﺗﻛﻭﻳﻥ ﻣﺭﻛﺏ ﻭﺳﻁﻲ ﻋﺩﺩﻩ ﺍﻟﺗﻧﺎﺳﻘﻲ ‪ ، 7‬ﻭﻋﻠﻰ‬
‫ﺿﻭء ﺗﺻﻧﻳﻑ ﺗﻭﺏ ﻳﻌﺩ ﺍﻻﻭﺭﺑﻳﺗﺎﻝ ﺍﻟﺷﺎﻏﺭ ﻓﻲ ‪ t2g‬ﺿﺭﻭﺭﻳﺎً ﻟﺗﻛﻭﻳﻥ ﺍﻟﻣﺭﻛﺏ ﺍﻟﻭﺳﻁﻲ ﺫﻱ ﻋﺩﺩ ﺍﻟﺗﻧﺎﺳﻕ ‪ 7‬ﺃﻱ ﺃﻥ‬

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‫م‪.‬ﺣﻮراء ﻣﻬﺪي‬ ‫اﻟﻤﺮﺣﻠﺔ اﻟﺜﺎﻟﺜﺔ‬ ‫ﻣﺤﺎﺿﺮات اﻟﻜﻴﻤﻴﺎء اﻟﺘﻨﺎﺳﻘﻴﺔ‬

‫ﺍﻻﻳﻭﻥ ﺍﻟﻔﻠﺯﻱ ﺍﻟﺫﻱ ﻻ ﻳﺗﻭﻓﺭ ﻓﻳﻪ ﻫﺫﺍ ﺍﻻﻭﺭﺑﻳﺗﺎﻝ ﺍﻟﺷﺎﻏﺭ ﻻﺳﺗﻘﺑﺎﻝ ﺍﻟﻣﺟﻣﻭﻋﺔ ﺍﻟﻣﻬﺎﺟﻣﺔ ﻻ ﻳﺣﺑﺫ ﺍﻟﺗﻔﺎﻋﻝ ﻭﻓﻕ‬
‫ﻣﻳﻛﺎﻧﻳﻛﻳﺔ ‪ SN2‬ﺍﻟﺗﻲ ﺗﺗﻣﺛﻝ ﺑﺗﻛﻭﻳﻥ ﺃﺻﺭﺓ ﺇﺿﺎﻓﻳﺔ ﻓﻲ ﺍﻟﺧﻁﻭﺓ ﺍﻟﺑﻁﻳﺋﺔ ﺍﻟﻣﺣﺩﺩﺓ ﻟﻠﺳﺭﻋﺔ ﻭ ﻳﻠﻳﻬﺎ ﻣﺭﺣﻠﺔ ﺍﻟﺗﻔﻛﻙ‬

‫ﺍﻟﺳﺭﻳﻌﺔ ﻛﻣﺎ ﻓﻲ ﺍﻟﺗﻣﺛﻳﻝ ﺍﻟﺗﺎﻟﻲ ‪:‬‬

‫‪ML5X + Y‬‬ ‫‪k1‬‬ ‫‪M L5XY‬‬ ‫]‪r = k1 [ML5X][Y‬‬
‫‪slow‬‬ ‫‪-X k2‬‬
‫‪fast ML5Y‬‬

‫‪Y‬‬ ‫‪Y‬‬
‫‪Y‬‬

‫ﺗﻛﻭﻳﻥ ﻣﺭﻛﺏ ﻭﺳﻁﻲ ﺳﺑﺎﻋﻲ ﺍﻟﺗﻧﺎﺳﻕ‬

‫ﻣﺛﺎﻝ ‪ :‬ﻧﺎﻗﺵ ﺍﻟﺟﺩﻭﻝ ﺍﻻﺗﻲ ﺍﻟﺫﻱ ﻳﻣﺛﻝ ﺛﻭﺍﺑﺕ ﺍﻟﺳﺭﻋﺔ ﻟﻣﻌﻘﺩﺍﺕ )‪ penta ammine ligand cobalt(III‬ﻭﺛﻭﺍﺑﺕ ‪Ka‬‬

‫ﻟﻣﻌﻘﺩ )‪. penta ammine aqua cobalt(III‬‬

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‫م‪.‬ﺣﻮراء ﻣﻬﺪي‬ ‫اﻟﻤﺮﺣﻠﺔ اﻟﺜﺎﻟﺜﺔ‬ ‫ﻣﺤﺎﺿﺮات اﻟﻜﻴﻤﻴﺎء اﻟﺘﻨﺎﺳﻘﻴﺔ‬

‫ﻣﻳﻛﺎﻧﻳﻛﻳﺔ ﺗﻔﺎﻋﻼﺕ ﺗﺄﻛﺳﺩ ﻭ ﺍﻻﺧﺗﺯﺍﻝ‪:‬‬

‫ﺗﻔﺎﻋﻼﺕ ﺍﻟﺗﺄﻛﺳﺩ ﻭ ﺍﻻﺧﺗﺯﺍﻝ ﻫﻲ ﺇﺣﺩﻯ ﺗﻔﺎﻋﻼﺕ ﺍﻟﻣﺭﻛﺑﺎﺕ ﺍﻟﺗﻧﺎﺳﻘﻳﺔ ﻭ ﺍﻟﺗﻲ ﺗﺗﺿﻣﻥ ﺍﻧﺗﻘﺎﻝ ﺍﻻﻟﻛﺗﺭﻭﻧﺎﺕ ﻣﺑﺎﺷﺭﺓ ﻣﻥ‬
‫ﺍﻟﻌﺎﻣﻝ ﺍﻟﻣﺧﺗﺯﻝ ﺍﻟﻰ ﺍﻟﻌﺎﻣﻝ ﺍﻟﻣﺅﻛﺳﺩ ‪ ،‬ﺃﻭ ﻳﺗﺿﻣﻥ ﺍﻧﺗﻘﺎﻝ ﺫﺭﺓ ﺃﻭ ﻣﺟﻣﻭﻋﺔ ﻣﻥ ﺍﻟﺫﺭﺍﺕ ﻭ ﻟﻛﻝ ﺗﻔﺎﻋﻝ ﻅﺭﻭﻓﻪ ﺍﻟﺧﺎﺻﺔ‬
‫‪ ،‬ﻭ ﺍﺑﺳﻁ ﺃﻧﻭﺍﻉ ﺗﻔﺎﻋﻼﺕ ﺗﺄﻛﺳﺩ – ﺍﺧﺗﺯﺍﻝ ﻳﺗﺿﻣﻥ ﻓﻘﻁ ﺍﻧﺗﻘﺎﻝ ﺍﻻﻟﻛﺗﺭﻭﻧﺎﺕ ﺑﻳﻥ ‪ [Fe(CN)6]-4‬ﻣﺛﻼً ﻭ ‪[Fe(CN)6]3-‬‬
‫ﺃﻭ ﺑﻳﻥ ‪ MnO4-‬ﻭ ‪ ، MnO4-2‬ﻭ ﻳﺟﺏ ﻣﻌﺭﻓﺔ ﺍﻟﻛﻳﻔﻳﺔ ﺍﻟﺗﻲ ﺗﻡ ﻓﻳﻬﺎ ﺍﻧﺗﻘﺎﻝ ﺍﻻﻟﻛﺗﺭﻭﻧﺎﺕ ﻣﻥ ﺧﻼﻝ ﺍﻟﻣﻳﻛﺎﻧﻳﻛﻳﺔ ﺍﻟﺗﻲ‬

‫ﺗﻅﻬﺭ ﻣﺳﻠﻛﻳﻥ ﺍﺳﺎﺳﻳﻳﻥ ﻣﺣﺗﻣﻠﻳﻥ ‪:‬‬

‫‪ ‬ﺗﻔﺎﻋﻼﺕ ﺧﺎﺭﺝ ﻛﺭﺓ ﺍﻟﺗﻧﺎﺳﻕ )‪(Outer-Sphere reaction‬‬

‫‪ ‬ﺗﻛﻭﻥ ﺗﻔﺎﻋﻼﺕ ﺍﻟﺗﺑﺎﺩﻝ ﺍﻻﻟﻛﺗﺭﻭﻧﻲ ﺳﺭﻳﻌﺔ ﺑﻳﻥ ﺍﻟﻣﺭﻛﺑﻳﻥ ‪ [Fe(CN)6]-4‬ﻭ ‪ [Fe(CN)6]3-‬ﻭﺗﺗﺻﻑ ﻫﺫﻩ‬
‫ﺍﻟﻣﺭﻛﺑﺎﺕ ﺑﻛﻭﻧﻬﺎ ﺫﺍﺕ ﺑﻧﻰ ﻫﻧﺩﺳﻳﺔ ﻣﺗﺷﺎﺑﻬﺔ ﻭ ﺃﻁﻭﺍﻝ ﺍﻵﺻﺭﺓ ﻓﻳﻬﺎ ﻣﺗﺳﺎﻭﻳﺔ ﺗﻘﺭﻳﺑﺎً ﻭ ﺫﺍﺕ ﺑﺭﻡ ﻭﺍﻁﺊ ﻭ‬

‫ﺧﺎﻣﻠﺔ ﻧﺣﻭ ﺗﻔﺎﻋﻼﺕ ﺍﻟﺗﻌﻭﻳﺽ‬

‫‪t2g6 eg0‬‬ ‫ﺍﻟﻌﺎﻣﻝ ﺍﻟﻣﺧﺗﺯﻝ ) ‪[Fe(CN)6]-4 (Fe+2‬‬

‫‪ t2g5 eg0 [Fe(CN)6]-3‬ﻭﺗﺗﻁﻠﺏ ﻫﺫﻩ ﺍﻟﺗﻔﺎﻋﻼﺕ ﻛﻣﻳﺔ ﻣﻥ ﻁﺎﻗﺔ ﺍﻟﺗﻧﺷﻳﻁ‬ ‫ﺍﻟﻌﺎﻣﻝ ﺍﻟﻣﺅﻛﺳﺩ ) ‪(Fe+3‬‬

‫ﻟﻐﺭﺽ ﺍﻟﺗﻐﻠﺏ ﻋﻠﻰ ﺍﻟﺗﻧﺎﻓﺭﺍﻟﻛﻬﺭﻭﺳﺗﺎﺗﻳﻛﻲ ﺍﻟﻧﺎﺷﺊ ﻣﻥ ﺍﻟﺷﺣﻧﺎﺕ ﺍﻟﻣﺗﺷﺎﺑﻬﺔ ‪.‬‬

‫ﻭﺗﻛﻭﻥ ﺗﻔﺎﻋﻼﺕ ﺍﻟﺗﺑﺎﺩﻝ ﺍﻻﻟﻛﺗﺭﻭﻧﻲ ﺑﻁﻳﺋﺔ ﻧﺳﺑﻳﺎً ﺑﻳﻥ ﺍﻟﻣﺭﻛﺑﻳﻥ ‪ [Co(NH3)6]+2‬ﻭ ‪ ، [Co(NH3)6]+3‬ﻓﺄﺣﺩ ﺍﻟﻣﺭﻛﺑﻳﻥ‬
‫ﺍﻟﻣﺗﻔﺎﻋﻠﻳﻥ ﺫﺍ ﺑﺭﻡ ﻭﺍﻁﺊ ) ﺍﻟﻌﺎﻣﻝ ﺍﻟﻣﺅﻛﺳﺩ ( ﻭ ﺍﻵﺧﺭ ﺫﻭ ﺑﺭﻡ ﻭﺍﻁﺊ ) ﺍﻟﻌﺎﻣﻝ ﺍﻟﻣﺧﺗﺯﻝ ( ﻭﺃﻁﻭﺍﻝ ﺍﻷﻭﺍﺻﺭ ﻣﺧﺗﻠﻔﺔ ‪.‬‬

‫‪) [Co(NH3)6]+2‬ﺍﻟﻌﺎﻣﻝ ﺍﻟﻣﺧﺗﺯﻝ ( ﺑﺭﻡ ﻋﺎﻟﻲ ﻓﻌﺎﻝ ﻧﺣﻭ ﺗﻔﺎﻋﻼﺕ ﺍﻟﺗﻌﻭﻳﺽ ‪t2g5 eg2‬‬

‫‪ ) [Co(NH3)6]+3‬ﺍﻟﻌﺎﻣﻝ ﺍﻟﻣﺅﻛﺳﺩ ( ﺑﺭﻡ ﻭﺍﻁﺊ ﺧﺎﻣﻝ ﻧﺣﻭ ﺗﻔﺎﻋﻼﺕ ﺍﻟﺗﻌﻭﻳﺽ ‪t2g6 eg0‬‬

‫ﻭﺗﺗﻁﻠﺏ ﻁﺎﻗﺔ ﺗﻧﺷﻳﻁ ﻋﺎﻟﻳﺔ ﺑﺎﻹﺿﺎﻓﺔ ﺇﻟﻰ ﺍﻟﺗﻧﺎﻓﺭ ﺍﻟﻛﻬﺭﻭﺳﺗﺎﺗﻳﻛﻲ ﻭ ﻟﺟﻌﻝ ﺍﻷﻭﺍﺻﺭ ﻣﺗﺳﺎﻭﻳﺔ ﻭ ﻛﺫﻟﻙ ﻹﻋﺎﺩﺓ ﺍﻟﺗﺭﺗﻳﺏ‬

‫ﺍﻻﻟﻛﺗﺭﻭﻧﻲ ‪ .‬ﻭﻳﻣﻛﻥ ﺇﻥ ﺗﺣﺻﻝ ﻫﺫﻩ ﺍﻟﺗﻔﺎﻋﻼﺕ ﺑﻳﻥ ﻣﺭﻛﺑﻳﻥ ﻟﻔﻠﺯﻳﻥ ﻣﺧﺗﻠﻔﻳﻥ ﺃﻭ ﺑﻳﻥ ﻣﺭﻛﺑﻳﻥ ﻣﺧﺗﻠﻔﻳﻥ ﻟﻧﻔﺱ ﺍﻟﻔﻠﺯ ‪ ،‬ﻭﻫﺫﻩ‬
‫ﺍﻟﺗﻔﺎﻋﻼﺕ ﺳﺭﻳﻌﺔ ﺟﺩﺍً ﻭ ﺗﺗﻁﻠﺏ ﻁﺎﻗﺔ ﺗﻧﺷﻳﻁ ﻭﺍﻁﺋﺔ ﻧﺳﺑﻳﺎً ‪ ،‬ﻛﻣﺎ ﻓﻲ ‪ [Fe(CN)6]-4‬ﻭ ‪.[IrCI6]-2‬‬

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‫‪ ‬ﺗﻔﺎﻋﻼﺕ ﺩﺍﺧﻝ ﻛﺭﺓ ﺍﻟﺗﻧﺎﺳﻕ ‪( Inner Sphere Reaction) :‬‬

‫ﻳﺗﺿﻣﻥ ﺑﻌﺽ ﺗﻔﺎﻋﻼﺕ ﺍﻟﺗﺄﻛﺳﺩ ﻭ ﺍﻻﺧﺗﺯﺍﻝ ﺫﺭﺓ ﺃﻭ ﻣﺟﻣﻭﻋﺔ ﻣﻥ ﺍﻟﺫﺭﺍﺕ ﻣﺷﺗﺭﻛﺔ ﺑﻳﻥ ﺍﻟﻌﺎﻣﻝ ﺍﻟﻣﺅﻛﺳﺩ ﻭ ﺍﻟﻌﺎﻣﻝ ﺍﻟﻣﺧﺗﺯﻝ‬

‫ﻳﺣﺻﻝ ﻣﻥ ﺧﻼﻟﻬﺎ ﺍﻧﺗﻘﺎﻝ ﺍﻻﻟﻛﺗﺭﻭﻧﺎﺕ ﻭ ﺗﻘﻭﻡ ﻫﺫﻩ ﺍﻟﺫﺭﺍﺕ ﺑﺗﻛﻭﻳﻥ ﺟﺳﺭ ﺑﻳﻥ ﺍﻟﻌﺎﻣﻝ ﺍﻟﻣﺧﺗﺯﻝ ﻭ ﺍﻟﻌﺎﻣﻝ ﺍﻟﻣﺅﻛﺳﺩ ﻳﺳﻬﻝ ﺍﻧﺗﻘﺎﻝ‬

‫ﺍﻻﻟﻛﺗﺭﻭﻧﺎﺕ ‪ ،‬ﻭﻳﻧﺑﻐﻲ ﺃﻥ ﻳﻛﻭﻥ ﺍﻟﻌﺎﻣﻝ ﺍﻟﻣﺧﺗﺯﻝ ﻓﻌﺎﻻً ‪ labile‬ﻭ ﺍﻟﻌﺎﻣﻝ ﺍﻟﻣﺅﻛﺳﺩ ﺧﺎﻣﻼً ‪ inert‬ﻛﻣﺎ ﻓﻲ ﺍﻟﺗﻔﺎﻋﻝ ﺍﻟﺗﺎﻟﻲ‪:‬‬

‫‪[Co(NH3)5CI]+2 + [Cr(H2O)6]+2‬‬ ‫‪H+‬‬ ‫‪[Co(H2O)6]+2‬‬ ‫‪+[Cr(H2O)5CI]+2‬‬ ‫‪+NH4+‬‬

‫‪Oxidant f.‬‬ ‫‪Reduct f.‬‬ ‫)‪High spin(labile‬‬ ‫‪Inert‬‬
‫‪Low spin‬‬ ‫‪High spin‬‬ ‫‪t2g5 eg2‬‬ ‫‪t2g3 eg0‬‬
‫‪inert‬‬
‫‪labile‬‬

‫ﺃﻥ ﺍﻳﻭﻥ ﺍﻟﻛﻠﻭﺭﻳﺩ ﺍﻟﺫﻱ ﻳﺗﺻﻝ ﺑﺎﻟﻛﺭﻭﻡ ﻛﺎﻥ ﻣﺗﺻﻼً ﺑﺎﻟﻛﻭﺑﻠﺕ ﻭ ﻗﺩ ﺍﻧﺗﻘﻝ ﺇﻟﻰ ﺍﻟﻛﺭﻭﻡ ﻣﻥ ﺧﻼﻝ ﺣﺎﻟﺔ ﺍﻻﻧﺗﻘﺎﻝ ﺍﻟﺗﻲ ﻳﺷﻛﻝ ﺍﻳﻭﻥ‬

‫ﺍﻟﻛﻠﻭﺭﻳﺩ ﻓﻳﻬﺎ ﺟﺳﺭﺍً ﺑﻳﻥ ﺍﻳﻭﻧﻲ ﺍﻟﻔﻠﺯﻳﻥ ‪ [(NH3)5Co-CI-Cr(H2O)5]+4‬ﻭ ﺇﺛﻧﺎء ﻋﻣﻠﻳﺔ ﺍﻻﻧﺗﻘﺎﻝ ﻳﻘﻭﻡ ﺍﻟﺟﺳﺭ ﺑﺄﻛﺳﺩﺓ ﺍﻟﻛﺭﻭﻡ‬

‫‪. Co+2‬‬ ‫‪ Cr+2‬ﻭ ﺍﺧﺗﺯﺍﻝ ‪Co+3‬‬ ‫ﻣﻥ ‪Cr+3‬‬

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‫ﺗﻔﺎﻋﻼﺕ ﺍﻟﺗﻌﻭﻳﺽ ﻓﻲ ﻣﻌﻘﺩﺍﺕ ﺍﻟﻣﺭﺑﻊ ﺍﻟﻣﺳﺗﻭﻱ ‪-:‬‬

‫ﺗﺯﺩﺍﺩ ﻓﺭﺹ ﺍﻟﺗﺄﺻﺭ ﺑﻳﻥ ﺍﻟﻣﺫﻳﺏ ﻭ ﺍﻻﻳﻭﻥ ﺍﻟﻣﺭﻛﺯﻱ ﺫﻟﻙ ﺑﺳﺑﺏ ﻛﻭﻥ ﺫﺭﺓ ﺍﻟﻔﻠﺯﺍﻟﻣﺭﻛﺯﻱ ﻗﺎﺑﻠﺔ ﻟﻠﺗﻔﺎﻋﻝ ﻓﻲ ﻣﻭﻗﻊ ﻣﻥ ﻣﻭﺍﻗﻊ‬
‫ﻣﺳﺗﻭﻱ ﺟﺯﻳﺋﺔ ﺍﻟﻣﻌﻘﺩ ‪ .‬ﻭﻟﻛﻲ ﻧﺧﻣﻥ ﻧﻭﻉ ﺍﻟﻣﻳﻛﺎﻧﻳﻛﻳﺔ ﺍﻟﻼﺯﻣﺔ ﻟﺣﺩﻭﺙ ﻫﺫﺍ ﺍﻟﻧﻭﻉ ﻣﻥ ﺗﻔﺎﻋﻼﺕ ﺍﻟﺗﻌﻭﻳﺽ ﻓﻲ ﻣﻌﻘﺩﺍﺕ ﺍﻟﻣﺭﺑﻊ‬

‫ﺍﻟﻣﺳﺗﻭﻱ ﻳﻣﻛﻥ ﺍﻟﻘﻭﻝ ﺍﻧﻬﺎ ﻟﻳﺳﺕ ﻣﻳﻛﺎﻧﻳﻛﻳﺔ ‪ SN1‬ﻻﻧﻬﺎ ﺗﺗﻁﻠﺏ ﻣﺭﻛﺑﺎً ﻭﺳﻁﻳﺎً ﺛﻼﺛﻲ ﺍﻟﺗﻧﺎﺳﻕ‪.‬‬

‫ﻭﻋﺎﺩﺓ ﻣﺎﻳﺗﻡ ﺩﺭﺍﺳﺔ ﻫﺫﻩ ﺍﻟﺗﻔﺎﻋﻼﺕ ﺑﻭﺍﺳﻁﺔ ) ﺗﺄﺛﻳﺭ ﺗﺭﺍﻧﺱ ‪ (trans effect‬ﻭﻳﺷﻳﺭ ﻫﺫﺍ ﺍﻟﻣﻔﻬﻭﻡ ﺍﻟﻰ ﺍﻥ ﻟﻳﻛﺎﻧﺩﺍﺕ ﻣﻌﻳﻧﺔ ﺗﺟﻌﻝ‬
‫ﻣﻥ ﺍﻟﺳﻬﻝ ﺍﺯﺍﺣﺔ ﺍﻟﻣﺟﺎﻣﻳﻊ ) ﺍﻟﻠﻳﻛﺎﻧﺩﺍﺕ( ﺍﻟﻣﻘﺎﺑﻠﺔ ﻟﻬﺎ ﻓﻲ ﻣﻭﻗﻊ ﺗﺭﺍﻧﺱ ﻓﻲ ﻣﻌﻘﺩ ﺍﻟﻣﺭﺑﻊ ﺍﻟﻣﺳﺗﻭﻱ ‪ .‬ﻭ ﺍﻟﻣﻌﻘﺩﺍﺕ ﺍﻟﺗﻲ ﺗﺗﻔﺎﻋﻝ‬
‫ﺑﻬﺫﻩ ﺍﻟﻁﺭﻳﻘﺔ ﺗﺣﺗﻭﻱ ﻋﺎﺩﺓ ﻋﻠﻰ ﺫﺭﺓ ﻣﺭﻛﺯﻳﺔ ﺫﺍﺕ ﻣﺟﺎﻝ ﻋﺎﻟﻲ ‪ ،‬ﻭ ﺗﺣﺗﻭﻱ ﻋﻠﻰ ﻣﺟﻣﻭﻋﺔ ﻣﺗﻧﺎﺳﻘﺔ ﺗﺩﻓﻊ ﺍﻻﻟﻛﺗﺭﻭﻧﺎﺕ ﻧﺣﻭ‬
‫ﺍﻟﺫﺭﺓ ﺍﻟﻣﺭﻛﺯﻳﺔ ﻭﻫﺫﻩ ﺍﻟﻣﺟﻣﻭﻋﺔ ﺗﻌﺩ ﺍﻛﺛﺭ ﻓﻌﺎﻟﻳﺔ ) ﺍﺳﻬﻝ ﺍﺳﺗﺑﺩﺍﻻً( ﻣﻥ ﺍﻟﺟﺯﻳﺋﺎﺕ ﺍﻟﻣﺗﻌﺎﺩﻟﺔ ﻣﺛﻝ ﺟﺯﻳﺋﺔ ‪ H2O‬ﻭﺗﺗﻣﺛﻝ ﻫﺫﻩ‬

‫ﺍﻟﻣﺟﻣﻭﻋﺔ ) ﺑﺑﻌﺽ ﺍﻻﻳﻭﻧﺎﺕ ﺍﻟﺳﺎﻟﺑﺔ (ﻭ ﺍﻓﺿﻝ ﻣﺛﺎﻝ ﻋﻠﻰ ﻫﺫﺍ ﺍﻟﻧﻭﻉ ﻣﻥ ﺍﻳﻭﻧﺎﺕ ﺍﻟﺫﺭﺓ ﺍﻟﻣﺭﻛﺯﻳﺔ ﻫﻭ ﺍﻳﻭﻧﻲ )‪.Pd(II),Pt(II‬‬

‫ﻓﻲ ﺗﻔﺎﻋﻼﺕ ﺗﺣﺿﻳﺭ ﺍﻳﺯﻭﻣﺭﺍﺕ ﺍﻟﻣﻌﻘﺩ ﺛﻧﺎﺋﻲ ﻛﻠﻭﺭﻭ ﺛﻧﺎﺋﻲ ﺍﻣﻳﻥ ﺑﻼﺗﻳﻥ )‪ (II‬ﻧﻼﺣﻅ ﻣﺎﻳﻠﻲ ‪:‬‬

‫ﺣﻳﺙ ﺍﻥ ﺍﻳﻭﻥ ﺍﻟﻛﻠﻭﺭﻳﺩ ﺍﻛﺛﺭ ﻗﺩﺭﺓ ﻋﻠﻠﻰ ﺍﻟﺗﺄﺛﻳﺭ ﺍﻟﺗﺭﺍﻧﺳﻲ ﻣﻥ ‪ ) NH3‬ﺍﻛﺛﺭ ﻓﻌﺎﻟﻳﺔ ‪،‬ﺃﻛﺛﺭ ﺍﺳﺗﺑﺩﺍﻻً ﺑﺄﺗﺟﺎﻩ ﺍﻟﻣﻭﻗﻊ ﺗﺭﺍﻧﺱ(‬
‫ﻓﺟﺯﻳﺋﺔ ‪ NH3‬ﻓﻲ ﺍﻟﺧﻁﻭﺓ ﺍﻟﺛﺎﻧﻳﺔ ﻻﻳﻣﻛﻥ ﺍﻥ ﺗﻛﻭﻥ ﻓﻲ ﺍﻟﻣﻭﻗﻊ ‪ trans‬ﻟﺟﺯﻳﺋﺔ ‪ NH3‬ﺍﻻﺧﺭﻯ ﻭ ﺑﺎﻟﺗﺎﻟﻲ ﻳﺗﻛﻭﻥ ﺍﻻﻳﺯﻭﻣﺭ ‪، cis‬‬

‫ﺍﻣﺎ ﺍﻻﻳﺯﻭﻣﺭ ‪ trans‬ﻓﺄﻧﻪ ﻳﺣﺿﺭ ﻋﻥ ﻁﺭﻳﻕ ﺗﻔﺎﻋﻝ ﺍﻟﻣﻌﻘﺩ ‪ [pt(NH3)4]+2‬ﻣﻊ ﺍﻳﻭﻥ ﺍﻟﻛﻠﻭﺭﻳﺩ ﻭ ﻛﺗﺎﻟﻲ ‪:‬‬

‫ﻳﺣﺙ ﺍﺳﺗﺑﺩﺍﻝ ﻓﻲ ﺍﻟﺧﻁﻭﺓ ﺍﻟﺛﺎﻧﻳﺔ ﺑﺟﺯﻳﺋﺔ ‪ NH3‬ﻓﻲ ﺍﻟﻣﻭﻗﻊ ﺗﺭﺍﻧﺱ ﻻﻳﻭﻥ ﺍﻟﻛﻠﻭﺭﻳﺩ ﺍﻻﻋﻠﻰ ﻗﺩﺭﺓ ﻋﻠﻰ ﺍﻟﺗﻭﺟﻳﻪ ﺍﻟﺗﺭﺍﻧﺳﻲ ﺑﺎﻳﻭﻥ‬
‫ﻛﻠﻭﺭﻳﺩ ﺍﺧﺭ ﻭ ﺑﺎﻟﺗﺎﻟﻲ ﻳﺗﻛﻭﻥ ﺍﻻﻳﺯﻭﻣﺭ ‪.trans‬‬

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‫ﻭﻳﻣﻛﻥ ﺗﺭﺗﻳﺏ ﺍﻟﻠﻳﻛﺎﻧﺩﺍﺕ ﺣﺳﺏ ﻗﺎﺑﻠﻳﺗﻬﺎ ﻟﺗﻭﺟﻳﻪ ﺍﻟﻠﻳﻛﺎﻧﺩﺍﺕ ﺍﻟﻣﻬﺎﺟﻣﺔ ﺍﻟﻰ ﺍﻟﻣﻭﻗﻊ ﺗﺭﺍﻧﺱ)ﻗﺩﺭﺗﻬﺎ ﻋﻠﻰ ﺗﺳﻬﻳﻝ ﺍﺳﺗﺑﺩﺍﻝ ﺍﻟﻠﻳﻛﺎﻧﺩ‬
‫ﺍﻟﻣﻘﺎﺑﻝ ﻟﻬﺎ ﻓﻲ ﺍﻟﻣﻭﻗﻊ ﺑﻠﻳﻛﺎﻧﺩ ﺍﺧﺭ )‪:(Y-‬‬

‫ﻭﺗﺳﻣﻰ ﺳﻠﺳﻠﺔ ﻟﻳﻛﺎﻧﺩ ﺍﻟﺗﻭﺟﻳﻪ ﺍﻟﻣﺿﺎﺩ )‪.(ligand directing series‬‬

‫ﻭﺑﻧﻔﺱ ﺍﻟﻁﺭﻳﻘﺔ ﻭ ﺑﺎﺳﺗﺧﺩﺍﻡ ﺧﺎﺻﻳﺔ ﺍﻟﺗﺎﺛﻳﺭ ﺍﻟﺗﺭﺍﻧﺳﻲ ﺗﺣﺿﺭ ﺍﻻﻳﺯﻭﻣﺭﺍﺕ ﺍﻟﺛﻼﺙ ﻟﻠﻣﻌﻘﺩ ]‪ [pt(py)NH3NO2CI‬ﻭﻳﻌﺗﻣﺩ‬
‫ﻧﺟﺎﺡ ﻫﺫﻩ ﺍﻟﻁﺭﻳﻘﺔ ﻋﻠﻰ ﺍﺧﺗﻼﻑ ﻗﻭﺓ ﺍﻟﺗﺎﺛﻳﺭ ﺍﻟﺗﺭﺍﻧﺳﻲ ﻟﻠﻳﻛﺎﻧﺩﺍﺕ‬

‫‪NO2‬‬

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