Chapter The d -Block Elements & ordination Chemistry Hill, Petrucci, McCreary & Perry 4 th Ed. The d-block Elements Groups 3-1 in the Periodic chart associated with the filling of the 3d, 4d, 5d electronic shells in the Atom. Groups 3 and 1 differ significantly from the others: They are softer, lower melting, have one principal oxidation state and they tend to form colorless compounds. Groups 4-11 in the Periodic Chart The transition Metals They tend to be high melting/boiling, very hard, magnetic, have variable (multiple) oxidation states (but 0 and are common to all) and many of their compounds are colored. They form ordination mpounds. The highest melting/boiling and hardest are found in groups 5 & 6
Transition Metal Electron nfigurations re electrons not used in bonding [Rare Gas] s d n- Lost first origin of common + oxidation state Ions: M + M 3+ M 4+ are far from a rare gas configuration. Lost consecutively as the oxidation state increases Ions have vacant s, p, d atomic orbitals and are Lewis Acids ordination Chemistry: Molecules having "lone pairs" of electrons are Lewis Bases and can chemically combine with the Lewis Acid Cations and form "ordination mpounds". Ligands F - Monodentate Ligands - Br - I - H- H PH 3 Despite the multiple "lone pairs" only NE is available for bonding! lone pairs Cyanide C N - bond pairs Bidentate Ligands xalate C C "ox" H 3 C C acetate "en" Both of these oxygens bind ethylenediamine Chelates: M n+ form rings Mn+ Ligands Tridentate Ligands "dien" NH diethylenetriamine Polydentate Ligands "EDTA" C H C C N N CH H C C C ethylenediaminetetraacetate
Werner s Theory of ordination Primary Valence: xidation State Secondary Valence: ordination Number Iron (III) - Fe 3+ = Primary Valence Hexaquoiron(III) => [Fe(H ) 6 ] 3+ secondary valence Hexammineiron(III) => [Fe( ) 6 ]3+ Hexacyanoiron(III) => [Fe() 6 ]3- [coordination sphere] note change in charge - algebraic sum of charges ordination Number & Structure ordination Number Linear Ag 3 Trigonal R 3 P Planar, all angles 10E Pt ordination Number & Structure ordination Number 4 Tetrahedral all angles 109.5 o Ni all angles 90.0 o Square Planar Ni
ordination Number & Structure ordination Number 5 Trigonal Bipyramid angles 10.0 o angles 90.0 o Ni Square Pyramid all angles 90.0 o ordination Number & Structure ordination Number 6 ctahedron all angles 90.0 o Very mmon Very Important M Trigonal Prism Uncommon angles 109.5 o Not Responsible for this Structure & Isomerism What must be the structure of [Ni Br ] - if it is known to have two distinct isomers? Draw them:
Structure & Isomerism What must be the structure of [Ni Br ] - if it is known to have only one isomer? Draw it: Stereoisomerism in ctahedral [MA B 4 ] ordination mplexes Examine the two unique ligands! "transoid" opposite "cisoid" adjacent cis Isomer trans Isomer Stereoisomerism in ctahedral [MA 3 B 3 ] ordination mplexes Examine the three unique ligands making triangles! N N fac Isomer N N parallel planes N mer Isomer N perpendicular planes
ptical Isomerism in ctahedral [MA en ] ordination mplexes H C H C "d"-cis Isomer "d" = dextrorotatory mirror plane "l"-cis Isomer "l" = levorotatory ptical Isomerism in ctahedral [MA en ] ordination mplexes Note: The "d" isomer does not superimpose when rotated 180 HN CH These two positions NH are interchanged Note: The bottom "en" flips from front to back. ptical Isomerism in ctahedral [MA en ] ordination mplexes Note: The "d" isomer does not CH superimpose when rotated 180 These two positions are interchanged Note: The bottom "en" flips from front to back. "d"-cis Isomer "d" = dextrorotatory "l"-cis Isomer "l" = levorotatory
nsequences of ptical Isomerism ptically active molecules have identical chemical and physical properties, unless the reacting species or the physical technique itself possesses chirality, itself optically active. Light is chiral. Plane polarized light will be rotated to the right or to the left a fixed number of degrees depending on which optical isomer is in the polarizer.