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 Unpair electron CFSE 1 2 3 4 5 6 7 8 9 10 t2g1 t2g2 t2g3 t2g3 eg1 t2g3 eg2 t2g4 eg2 t2g5 eg2 t2g6 eg2 t2g6 eg3 t2g6 eg4 -4Dq -8Dq -12Dq -6Dq 0Dq -4Dq + P -8Dq + 2P -12Dq + 3P -6Dq + 4P 0Dq + 5P

Octahedral, Tetrahedral & Square Planar dz2 dx2-y2 dxz dxy dyz CF Splitting pattern for various molecular geometry dxz dz2 dx2-y2 dxy dyz dx2-y2 dz2 dxz dxy dyz Octahedral Tetrahedral Square planar Mostly d8 (Majority Low spin) Strong field ligands i.e., Pd2+, Pt2+, Ir+, Au3+ Pairing energy Vs.  Weak field  < Pe Strong field  > Pe Small   High Spin

Color Absorption of Co3+ Complexes The Colors of Some Complexes of the Co3+ Ion Complex Ion Wavelength of Color of Light Color of Complex light absorbed Absorbed [CoF6] 3+ 700 (nm) Red Green [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 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. 750 430 650 580 560 490 400 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.

Light absorption Properties of Metal Complexes Recording the absorption Spectrum

Complex Influence on Color Compounds of Transition metal complexes solution. 800 430 650 580 560 490 400 [Fe(H2O)6]3+ [Ni(H2O)6]2+ [Zn(H2O)6]2+ [Co(H2O)6]2+ [Cu(H2O)6]2+

Determine the field strength by measuring absorbed energy Spectrophotometry method Absorbancy wavelength  max Absorded energy is energy used for exitation or the electrons from t2g to tg

TEORI ORBITAL MOLEKUL Graphically these two orbitals look like this:

Constructive Overlap of two 1s orbitals Destructive Overlap of two 1s orbitals

Bonding orbital Anti-bonding orbital Lower energy Higher energy Stable Unstable Favorable for electrons Unfavorable for electrons Electrons exist between nuclei Electrons exist outside

Energetically, the molecular orbitals split. The 1s lies lower in energy. The 1s* is higher in energy.

The head-on overlap of two corresponding p atomic orbitals on different atoms, such as 2px with 2px, produces: bonding orbital antibonding orbital

Graphically, these orbitals look like this:

Graphically these orbitals look like this:

N N 7 electrons + 7 electrons

Orbital Molekul [Co(NH3)6]3+

Orbital Molekul [CoF6]3-