Part5: Transition Metal and Coordination Chemistry Website: www.mwit.ac.th/~teppode SORACHAI SAE-LIM DEPARTMENT OF CHEMISTRY MAHIDOL WITAYANUSORN SCHOOL
2 The elements in the Periodic Table which correspond to the d-orbitals and f-orbitals
3 ม เลขออกซ เดช นได หลายค า
4 Complex Mn 2+ Mn 3+ Mn 4+ Mn 6+ Mn 7+
5 Central atom Ligands Counter ion
6 A coordination complex consists of a central atom, usually a metal ion, bound to a set of ligands by coordinate bonds.
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ป จจ ยท ม ผลต อโครงสร างของสารประกอบ 9 Steric hindrance Steric effect Electronic structure of metal
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Coordination number 1 11 Coordination number 2 [Fe{NS 2 (Me) 2 Ph 2 ) 2 } 2 ]
Coordination number 3 12 Trigonal planar structures are observed, and examples involving d 10 metal centre's include: [Fe{N(SiMe 3 ) 2 } 3 ]
Coordination number 3 Trigonal planar, the parent shape of three-coordination, and the way it can transform to other known geometries. 13
Coordination number 4 14 Tetrahedral complexes
Coordination number 4 15 Square planar complexes are rarer than tetrahedral, and are often associated with d 8 configurations: e.g. [PdCl 4 ] 2-, [PtCl 4 ] 2-, [AuCl 4 ] -, [AuBr 4 ] -
Coordination number 5 16
Coordination number 6 17
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Monodentate ligands 19
Bidentate ligands 20
Tridentate ligands 21 Tetradentate ligands
จงบอกชน ดของ EDTA 22
จงบอกชน ดของ ligand ข อ a-d 23
Naming Coordination Compounds 24 A. To name a coordination compound, no matter whether the complex ion is the cation or the anion, always name the cation before the anion. (This is just like naming an ionic compound.) NaCl Na + Cl - Sodium chloride K 4 [Fe(CN) 6 ] potassium hexacyanoferrate(ii) Solution: potassium is the cation and the complex ion is the anion.
Naming Coordination Compounds 25 B. In naming the complex ion: 1. Name the ligands first, in alphabetical order, then the metal atom or ion. Note: The metal atom or ion is written before the ligands in the chemical formula. [Cr(NH 3 ) 3 (H 2 O) 3 ]Cl 3 Solution: The complex ion is inside the parentheses, which is a cation. The ammine ligands are named before the aqua ligands according to alphabetical order. triamminetriaquachromium (III) chloride
2. The names of some common ligands are listed in Table 1. 26 2.1For anionic ligands end in "-o"; for anions that end in "-ide"(e.g. chloride), "-ate" (e.g. sulfate, nitrate) "-ite" (e.g. nirite) change the endings as follows: -ide -o -ate -ato -ite -ito
Table 1. Names of Some Common Ligands 27
2.2For neutral ligands, the common name of the molecule is used 28 H 2 NCH 2 CH 2 NH 2 (ethylenediamine). Important exceptions: water is called aqua, ammonia is called ammine carbon monoxide is called carbonyl N 2 is called dinitrogen is called dioxygen O 2
Table 2. Names of Some Common Ligands 29
3. Greek prefixes are used to designate the number of each type of ligand in the complex ion, e.g. di-, tri- and tetra-. 3.1 If the ligand already contains a Greek prefix (e.g. ethylenediamine) 3.2 If it is polydentate ligands (ie. can attach at more than one binding site) the prefixes bis-, tris-, tetrakis-, pentakis-, are used instead. The numerical prefixes are listed in Table 3 30
4. After naming the ligands, name the central metal. 4.1 If the complex ion is a cation, the metal is named same as the element. For example, Co cobalt Pt platinum. 4.2 If the complex ion is an anion, The name of the metal ends with the suffix ate. For example, Co cobaltate Pt platinate 4.3 For some metals, the Latin names are used in the complex anions For example Fe is called ferrate (not ironate). 31
Table 4: Name of Metals in Anionic Complexes 32
5. Following the name of the metal, the oxidation state of the metal in the complex is given as a Roman numeral in parentheses. 33 Na 2 [NiCl 4 ] sodium tetrachloronickelate(ii) C. To name a neutral complex molecule, follow the rules of naming a complex cation. Remember: Name the (possibly complex) cation BEFORE the (possibly complex) anion. Pt(NH 3 ) 2 Cl 4 diamminetetrachloroplatinum(iv) Solution: This is a neutral molecule because the charge on Pt +4 equals the negative charges on the four chloro ligands.
[Pt(NH 3 ) 5 Cl]Br 3 34 Answer: pentaamminechloroplatinum(iv) bromide Solution: The complex ion is a cation, the counter anion is the 3 bromides. The charge of the complex ion must be +3 since it bonds with 3 bromides. The NH 3 are neutral molecules while the chloride carries - 1 charge. Therefore, the oxidation number of platinum must be +4.
[Pt(H 2 NCH 2 CH 2 NH 2 ) 2 Cl 2 ]Cl 2 35 Answer: dichlorobis(ethylenediamine)platinum(iv) chloride Solution: ethylenediamine is a bidentate ligand, the bisprefix is used instead of di-
K 4 [Fe(CN) 6 ] 36 Answer: potassium hexacyanoferrate(ii) Solution: potassium is the cation and the complex ion is the anion. Since there are 4 K + binding with a complex ion, the charge on the complex ion must be - 4. Since each ligand carries 1 charge, the oxidation number of Fe must be +2. The common name of this compound is potassium ferrocyanide.
Can you give the molecular formulas of the following coordination compounds? 37 1. hexaammineiron(iii) nitrate 2. ammonium tetrachlorocuprate(ii) 3. sodium monochloropentacyanoferrate(iii) 4. potassium hexafluorocobaltate(iii) Can you give the name of the following coordination compounds? 5. [CoBr(NH 3 ) 5 ]SO 4 6. [Fe(NH 3 ) 6 ][Cr(CN) 6 ] 7. [Co(SO 4 )(NH 3 ) 5 ] + 8. [Fe(OH)(H 2 O) 5 ] 2+
Answers: 38 1. [Fe(NH 3 ) 6 ](NO 3 ) 3 2. (NH 4 ) 2 [CuCl 4 ] 3. Na 3 [FeCl 1 (CN) 5 ] 4. K 3 [CoF 6 ] 5. pentaamminebromocobalt(iii) sulfate 6. hexaammineiron(iii) hexacyanochromate (III) 7. pentaamminesulfatocobalt(iii) ion 8. pentaaquahydroxoiron(iii) ion
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เอกสารอ างอ ง 40 บทปฏ บ ต การเคม ท วไป 1 มหาว ทยาล ยมห ดล จ นตนา ส ร พ ทยานานนท, การว เคราะห โครงสร างผล ก, พ มพ คร งท 1, 2537. Emil J. Slowinski, Wayne C. Wolsey, William L. Masterton, Chemical Principles in The Laboratory, 8 th ed. Thomson Brooks/Cole Date Published: 2000. Naming Coordination Compounds http://www.chemistry.wustl.edu/~edudev/labtutorials/naming_coord_comp.html