1d Flashcards
whats an organometallic complex
a transition metal - Carbon!!!
describe zeise’s salt structure
u have Pt(2) as the metal
this is bonded to 3Cls
this is also bonded perpendicularly to an ethene !!
thats the structure but u can also put brackets around it and write K+ H2O if u wanna
+ being the charge on K.
whats Nickel tetracarbonyl
Ni(CO)4
its what ppl first used in order to purify Ni
example of a carbonyl anion cluster
[Fe(CO)13]^2-
describe ferrocene
cyclopentane
Fe
cyclopentane
cyclopentane = C5H5-
Fe = 2+
cyclopentane = C5H5-
why were ppl shocked about freeocene
bc its a compound made up of a metal,, and hydrocarbon chain,, but its so so stable??
so the bonding has to be unique bc whattt
describe sigma bonding between a metal and a ligand
ligand donating a lone pair to the metal
u have one overlap
describe pi bonding between a metal and a ligand
the ligand and metal empty p orbitals have constructive overlap forming a pi bond
u have 2 overlaps
describe a delta bond
its when the d orbitals of a metal and ligand all overlap with constructive overlap!!
the d orbitals are like wheels kinda,, so their middle is kinda pointing away from u
u have 4 overlaps!!
what block of orbitals can do pi and delta bonding
only the d block can be pi and delta bonding!!!
main group organometallics are what
metals of the s and p orbital
they can only do sigma bonding
no pi or delta bonding THERE ARE NO STABLE CARBONYL COMPOUNDS OF THE S AND P BLOCK
d block organometallics have a strong preference for what
they have a strong valence electron count preferance!!!
they prefer 18 and sometimes 16e-!!!
describe an octahedral complex with sigma bonding only
u have the a1g, t1u, eg bonding orbitals (12 e can fit here)
u have the t2g nonbonding orbital and the eg* orbitals
theres a small 🔺o meaning u can put e- in the t2g or the eg* and it doesnt rlly matter!! bc the eg* is only weakly antibonding.
so theres no preferance for the number of e- u have.
when u have an octahedral complex with only sigma bonding,, where are u e- coming from
the metal atomic orbitals d, s, p
the ligand sigma donor orbitals: 12e-
how many e- does a ligand offer
2e- each
in a octahedral complex with only sigma bonding,, u have 12e- from the ligand,, (filling up the a1g, t1u, eg) where do the metals e- go
either the t2g nonbonding or the eg* thats weakly antibonding,, tbh it rlly doesnt matter bc the 🔺o is so small it can go in either,, so the number of metal e- u have doesnt rlly matter,, bc the energy diff between the orbitals is so low.
describe the e- diagram when u have sigma donors and pi acceptor ligands!!! where are u e- coming from
u have the d, s, p coming from the metal atomic orbitals
u have the ligand sigma donor orbitals
u have the empty ligand pi acceptor orbitals
when u have sigma donors and pi acceptor orbitals:
what are higher in energy
the sigma donors are lower in energy and u have 12e- from here
then u have the empty pi acceptor orbitals which are higher in energy
when u have sigma donors and pi acceptors,, what do the empty pi acceptor orbitals overlap with
they overlap with the t2g* and the t2g bonding
it therefore overlaps with the d orbitals from the metal
when u have sigma donors and pi acceptor ligands,, what do the ligand sigma donor orbitals overlap with
they overlap with the the t2g and t2g* along with all the other orbitals aswell
when u have sigma donors and pi acceptors,, why can the empty pi acceptor orbitals overlap with the t2g d orbitals
bc they have t2g symmetry
when u have sigma donors and empty pi acceptor ligands, whats diff about the t2g orbitals when we compare them to just sigma donor orbitals
the t2g was nonbonding,, however it is now strongly bonding !!!
meaning u have a1g, t1u, eg and t2g as ur bonding orbitals,, giving u 9 bonding MO’s and therefore 18e- can go in here.
this therefore gives us a diff stability as we have 9BO instead of just 6BO.
okay so when we have a sigma bonor and pi acceptor orbitals,, why is t2g now strongly bonding instead of non bonding
bc u have a crazy massive 🔺o!!!!
and this means u can have more than 18e- but lowks its bad news bc the eg* is insanely antibonding and very high in energy±
why do sigma donor and pi acceptors like 18 e- or less
bc u have a large 🔺o
meaning u have 9 very strong bonding MO.
but the gap between the t2g and eg* is insanely big,, meaning eg* is a very high energy orbital!!! so putting e- in here is bad news.
with good pi acceptor ligands,, what e- config becomes the best config for Oh complexes
when we have an octahedral complex with good pi acceptor ligands we look for 18e- configurations,, to fill all the 9 bonding MO’s!!!
and no more than 18 bc the first antibonding, eg* orbital is extremely high in energy and putting e- in here is bad news.
why are Cr, Mo and W hexacarbonyl complexes colourless
bc their 🔺o is so large that the transition from t2g –> eg* requires energy from the UV region. which is higher in energy than the vis region
we have the octahedral 18e-0 configuration for complexes with good pi acceptor ligands,, what other cstable config do we have
the 16e- square planar geometry where 1 d orbital is no longer appropriate in bonding.
when we have a 16e- configuration in a square planar geometry how many e- do we get from everything
we get 8e- from the 4 ligands
meaning we need 8e- from the metal
but theres not many metals that give us 8e-
what metals give us 8e-
RH1
Ir1
Pd2
Pt2
what type of e- compound is zeise’s salt
its a 16e- compound
u have Pt2
bonded to 3 Cls
and an orthogonal ethene. and this is an anion so u need the square brackets and the - charge on the outside.
what is preferred sterically,, square planar or tetrahedral
tetrahedral is preferred.
square planar is usually seen with 2nd and 3rd row d block metals bc theyre larger and allow the 4 ligands to be further away when theyre in the square planar geometry.
