TMs 2 - Ch 8-11 - TM stability, e-counting, aqueous solns

state the 18 e- rule, its implications for reactivity, and its exceptions

d e- + ligand e^- + charge = 18 e^-

if 18 e^- = stable

< 18 e^- = reduced (+ e^-)

> 18 e^- = oxidised (- e^-)

square planar = 16 e^- (d$_{x²-y²}$ destabilised, - 2e^-

L-type ligand

2 e^- donor

“neutral”

dative bond formed

X-type ligand

1 e- donor

radical

covalent bond

Z-type ligand

0 e- donor

lewis acid - accepts 2 e- from metal

dative bond

list 5 factors that affect the strength of M-M bonding

1. spatial overlap: lower down + to left of periodic table = most diffuse orbitals so best spatial overlap

2. oxidation state: affects how e- dense metal is + how contracted

3. bond order of M-M bond: $\uparrow$ BO = $\downarrow$ bond length

4. ligand size

5. ligand number

6. bridging ligands present?

Describe the bonding in the $\eta^1$ allyl ligand

X-type

Describe the bonding in the $\eta^3$allyl ligand

LX

what is a $\mu_n$ ligand?

bridging ligand

n = no. of M centres coordinated to

what is a $\eta^n$ ligand?

$\eta$ = hapticity, no. of atoms that coordinate to metal.

e.g. Cp = $\eta^5$

polyalkenes may have multiple hapticities available.

what does $\kappa$ notation mean?

signals that the atom after it is the ligating one

e.g. dimethylphosphane-$\kappa$P = P ligates

electrons counting table

How does the strength of M-L bonding vary with oxidation state?

$\uparrow$ ox = stronger bonding

polarise ligand e- density more strongly

why don’t TMs past Mn access their maximum oxidation state?

Z_eff $\uparrow$ across period

I.E. $\uparrow$

stability $\downarrow$

How does oxidising power change across a period?

best ox power = $\downarrow$ stability