Ligands and Complex Ions Flashcards
what is a ligand?
molecule or ion that can donate a pair of electrons to the transition metal ion to form a coordinate bond
what is a coordinate bond?
- dative covalent bond to metal ion or metal and ligands
what is a coordination number?
total number of coordinate bonds formed between the central transition metal ion and its ligands
what is a complex ions?
transition metal ion bonded to one or more ligands by coordinate bonds
what is a monodentate ligand?
a ligand which is able to donate one pair of electrons to a central metal ion
what is a bidentate ligand?
a ligand that donates two lone pair of electrons to a central metal ion and forms two coordinate bonds
what are examples of monodentate ligands?
- water, chloride ions and ammonia
water and ammonia have a 0 charge, and chloride has a charge of 1
what are examples of bidentate ligands?
NH2CH2CH2NH2 = en
- 1,2-diaminoethane
- lone pairs of electrons on the nitrogen atoms
what are the shapes of complex ions?
- octahedral shape
- tetrahedral shape
- square planar shape
what is the shape for six-fold coordination?
- octahedral
what is the shape of four-fold coordination?
- square planar or tetrahedral shapes
what is an example of octahedral shape?
- hexaaqua complexes like [Cu(H2O)6]2+, [Fe(H2O)6]3+, [Mn(H2O)6]2+
what is the bond angle In octahedral shapes?
90
what is the complex of platinum called?
- platin
- Pt(NH3)2Cl2
what are the types of stereoisomerism involved in transition metals?
- cis-trans isomerism
- optical isomerism
what is the bond angle of tetrahedral complexes?
109.5
what is the bond angle of square planar complexes?
90
what is an example of tetrahedral complexes?
- many tetarchloro complexes
- e.g. CuCl42- and CoCl42-
- chlorine is too big to have 6 coordinate bonds
what is an example of square planar complexes?
complexes of Pt such as platin
what complex has no stereoisomers?
tetrahedral complexes
what type of stereoisomers do square planar complexes have?
- cis-trans isomerism
what is a cis isomer?
- two identical ligand are 90 degrees apart
what is a trans isomer?
- two identical ligands are 180 degrees apart
what is the stereoisomerism found in octahedral complexes?
- cis-trans isomerism
- optical isomerism
what type of isomers can form optical isomers?
- only cis isomers can form optical isomers
- bidentate ligands
what is the use of cis-platin?
anti cancer drug
- binds to DNA prevent cell division
what are benefits of chemotherapy?
attacks tumours causing the tumours to shrink in size
what are the risks of chemotherapy?
- unpleasant side effects
