Topic 7: Introduction to Transition Metal Complexes Flashcards

1
Q

3 d-block elements that don’t always behave as transition metals and why

A

No partially filled d-subshell

Sc: electron configuration is [Ar] 3d^1 4s^2. It exists as Sc^3+: electron configuration is [Ar] 3d^0 4s^0 so behaves as an f-block element

Zn, electron configuration is [Ar] 3d^10 4s^2. It exists as Zn^2+: electron configuration is [Ar] 3d^10 4s^0

Au
electron configuration is [Xe] 4f^14 5d^10 6s^1. It exists as Au^+: electron configuration is [Xe] 4f^14 5d^10 6s^0 (not a transition metal) and Au^3+: [Xe] 4f^14 5d^8 6s^0 (is a transition metal)

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2
Q

What makes a d-block element a tradition element?

A

Form stable ions with partially filled d-subshell

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3
Q

Which orbital is filled first, 3d or 4s in transition metals + what are the exceptions?
Does this differ on transition complexes/compounds

A

4s as lower in energy here

Cr: [Ar] 3d^5 4s^1 (prefers to have 1 electron in each d orbital than paired in 4s) and Cu: [Ar] 3d^10 4s^1 (prefers to pair all 3d electrons over 4s)

Yes, 3d filled first as lower in energy here

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4
Q

Calculate d^n

A

number of outer s + d electrons (group number)

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5
Q

Requirement for colourless transition metal complexes in terms of d-electrons

A

Entirely empty or entirely full d-subshells

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6
Q

Source of colour in transition metal complexes

A

d-electrons (unpaired) moving between d-orbitals and absorbing energy (light in visible region of spectrum)

Ligand –> metal / metal –> ligand charge transfer (movement of electrons)

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7
Q

diamagnetic compounds contain … and are … from a magnetic field

A

only paired electrons
repelled

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8
Q

paramagnetic compounds contain … and are … from a magnetic field

A

unpaired electron(s)
attracted

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9
Q

Do paramagnetic or diamagnetic effects dominate?

A

paramagnetic

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10
Q

u eff =

A

root (n (n + 2))
n= dumber of unpaired electrons in d-subshell

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11
Q

Sc to Mn have … oxidation states + … number of oxidation states

A

increasing
increased

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12
Q

Fe to Zn have … oxidation states + … possible oxidation states

A

lower
fewer

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13
Q

High oxidation state complexes are … agents

A

oxidising

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14
Q

Low oxidation state complexes are … agents

A

reducing

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15
Q

Why is it energetically favourable to form ions from transition elements when it requires energy to remove electrons?

A

Solvation energy or lattice energy is more negative than the ionisation energy is positive.
Overall release of energy

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16
Q

Why can’t all ions achieve high oxidation states e.g. Fe^+7

A

Energetically unfavourable
Solvation energy or lattice energy is less negative than the ionisation energy is positive

17
Q

dative bond

A

ligand donates pair of electrons to the central atom/ion

18
Q

Pauling’s electroneutrality principle

A

Change of an atom or ion can only be +/-1 |z|>/= 1
So any charges higher, are very attracted to that change forming a bond, charge is then spread to ligands

e.g. A metal with 2+ charge and bonded to 6 water will spread charge to Os and each will have an average charge of 1/3+. They will on average donate 1/3 of electron to 2+metal centre. This will continue to Hs, each having 1/6+ while the central metals and O will have a charge of 0

19
Q

Transition metal complexes can be …

20
Q

Electronegativity of … is …
The range of metals is … to …

A

1.7
50% covalent and 50% ionic character
1.4
2.0

21
Q

In higher oxidation states of the metal, bonds become more … because …

A

covalent
the ligands have to donate more electron density to the ligand to satisfy Pauling’s

22
Q

What metal charge is the most acidic?
What coordinates

A

3^+
hydroxides instead of water

23
Q

Ligands can be … such as, … such as … and occasionally … such as …
They all donate …

A

neutral
NH3 CO H2O PR3 SR2
anionic
CN^- Me^- NH2^- Cl- I-
cationic NO^+
2 electrons

24
Q

cisplatin is

A

[Pt(NH3)2(Cl)2]

25
Inner sphere ligands are ...
atoms bonded directly to central metal ions
26
Outer sphere ligands are ...
ligands associated with the inner sphere complex (outside square brackets)
27
Ambidentate ligands have ...
more than one potential donor atom that could coordinate (1 coordinates and occupies 1 coordination site)
28
Bidentate and multidentate ligands
bidentate have 2 donor atoms that bind to the same metal at the same time (they occupy 2 coordinate site) Same principle for more than 2 doctor atoms in multidentate
29
Most complexes with 4 ligands form ... complexes and others form ... complexes
tetrahedral square planar
30
Isomers of square planar complexes
2 geometric isomers: cis and trans
31
Isomers of octahedral complexes
geometric isomers: cis and trans geometric isomers: fac and mer optical isomers (mirror image)