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Pengantar Kimia Koordinasi Kimia Anorganik II COMPOUNDS NOMENCLATURE [Co(NH3)3(NO2)3] Triamintrinitrokobalt (III) [Pt(NH3)2Cl2] Diamindikloroplatina (II) [Ni(DMG)2] Bisdimetilglioksimatonikel (II) [Cr(NH3)6](NO3)3 Heksaminkromium (III) nitrat [Co(NH3)5H2O]Cl3 Akuopentaminkobalt (III) klorida [Pt(NH3)4NO2Cl](SO4)2 Tetraminkloronitroplatina (IV) sulfat K3[Al(C2O4)3] Kalium trioksalatoaluminat (III) NH4[Cr(NH3)2(NCS)4] Ammonium diamintetratiosianatokromat (III) Ca2[Fe(CN)6] Kalsium heksasianoferrat (II) d-Orbitals and Ligand Interaction (Octahedral Field) Ligands approach metal d-orbitals pointing directly at axis are affected most by electrostatic interaction d-orbitals not pointing directly at axis are least affected (stabilized) by electrostatic interaction The six negative charges are equally distributed in a sphere around the metal Crystal Field Theory (CFT) 6Dq = 0.6 o 4Dq = 0.4 o High Spin Vs. Low Spin (d1 to d10) Electron Configuration for Octahedral complexes of metal ion having d1 to d10 configuration [M(H2O)6]+n. Only the d4 through d7 cases have both high-spin and low spin configuration. Electron configurations for octahedral complexes of metal ions having from d1 to d10 configurations. Only the d4 through d7 cases have both high-spin and low-spin configurations. CFSE (Crystal Field Stabilization Energy) Octahedral complexes, weak field ligand, high spin complexes n Konfiguration 1 2 3 4 5 6 7 8 9 10 t2g1 t2g2 t2g3 t2g3 t2g3 t2g4 t2g5 t2g6 t2g6 t2g6 eg1 eg2 eg2 eg2 eg2 eg3 eg4 Unpair electron 1 2 3 4 5 4 3 2 1 0 CFSE -4Dq -8Dq -12Dq -6Dq 0Dq -4Dq + P -8Dq + 2P -12Dq + 3P -6Dq + 4P 0Dq + 5P Octahedral, Tetrahedral & Square Planar CF Splitting pattern for various molecular geometry dx2-y2 dz2 dx2-y2 Octahedral Tetrahedral M dxy dyz dxz M Square planar dxy M dz2 dxy dyz dxz Pairing energy Vs. Weak field < Pe Strong field > Pe dx2-y2 dz2 Small High Spin dxz dyz Mostly d8 (Majority Low spin) Strong field ligands i.e., Pd2+, Pt2+, Ir+, Au3+ Color Absorption of Co3+ Complexes The Colors of Some Complexes of the Co3+ Ion Complex Ion Wavelength of light absorbed Color of Light Absorbed Color of Complex [CoF6] 3+ 700 (nm) Red [Co(C2O4)3] 3+ 600, 420 Yellow, violet Dark green [Co(H2O)6] 3+ 600, 400 Yellow, violet Blue-green [Co(NH3)6] 3+ 475, 340 Blue, violet Yellow-orange [Co(en)3] 3+ 470, 340 Blue, ultraviolet Yellow-orange [Co(CN)6] 3- 310 Ultraviolet Pale Yellow Green The complex with fluoride ion, [CoF6]3+, is high spin and has one absorption band. The other complexes are low spin and have two absorption bands. In all but one case, one of these absorptions is in the visible region of the spectrum. The wavelengths refer to the center of that absorption band. Colors & How We Perceive it 650 580 800 560 400 Artist color wheel showing the colors which are complementary to one another and the wavelength range of each color. 430 490 Black & White When a sample absorbs light, what we see is the sum of the remaining colors that strikes our eyes. If a sample absorbs all wavelength of visible light, none reaches our eyes from that sample. Consequently, it appears black. If the sample absorbs no visible light, it is white or colorless. Absorption and Reflection If the sample absorbs all but orange, the sample appears orange. Further, we also perceive orange color when visible light of all colors except blue strikes our eyes. In a complementary fashion, if the sample absorbed only orange, it would appear blue; blue and orange are said to be complementary colors. 650 580 750 400 560 430 490 Light absorption Properties of Metal Complexes Recording the absorption Spectrum Complex Influence on Color Compounds of Transition metal complexes solution. 650 800 400 430 [Fe(H2O)6]3+ [Ni(H2O)6]2+ [Co(H2O)6]2+ [Zn(H2O)6]2+ [Cu(H2O)6]2+ 580 560 490 Determine the field strength by measuring absorbed energy Spectrophotometry method E Absorbancy h.c Absorded energy is energy used for exitation or the electrons from t2g to tg max wavelength TEORI ORBITAL MOLEKUL • Graphically these two orbitals look like this: 53 Constructive Overlap of two 1s orbitals Destructive Overlap of two 1s orbitals 54 Bonding orbital Anti-bonding orbital Lower energy Higher energy Stable Unstable Favorable for electrons Unfavorable for electrons Electrons exist between nuclei Electrons exist outside 55 • Energetically, the molecular orbitals split. 1. The 1s lies lower in energy. 2. The 1s* is higher in energy. 56 • The head-on overlap of two corresponding p atomic orbitals on different atoms, such as 2px with 2px, produces: 1. bonding orbital 2. σ 2pxantibonding orbital σ* 2px 57 • Graphically, these orbitals look like this: 58 • Graphically these orbitals look like this: 59 *2px *2py *2pz 2p 2p 2px 2py N 2pz * 2s 2s 2s 2s N 7 electrons + 7 electrons * 1s 1s 1s 1s 60 Orbital Molekul [Co(NH3)6]3+ 61 Orbital Molekul [CoF6]3- 62 63 64 65 66 67