8d Flashcards
what do Cp rings also act like
they behave lke aromatic rings
can u do friedels acylation on a ferrocene and what happens
u add a CH3,C=O,Cl to ferrocene
and basically u add the molecule without the Cl
so u would have ferrocene with C=O, CH3 on one of the carbons of Cp.
what if u have ferrocene and Bu-Li,
u add Li to one of the carbons
and then if u add EtI to this u get ferrocene with Et where the Li was
whats a cycloheptatriene
cyclo = cyclic
hepta = 7C’s
triene = 3 double bonds
so then u have a C with no double bonds but its calm
whats cool about cycloheptatriene
it already has 6 pi electrons
bc u have 3 double bonds
but u have C7H8,, so u need to remove a hydride, H- to make it aromatic ,, so u get C7H7+ and this still has 6e-
this is called tropylium
cycloheptatriene is a what electron donor
its a 6 electron donor
aka n.6, if u use all the double bonds at the same time.
once u turn the cycloheptatriene into C7H7+,, what do u do
u form a vacant p orbital
u make it aromatic
its now a n.7 molecule
u draw it with a circle in the middle
describe dinitrogen and what its isoelectronic with
its NtripleN
its isoelectronic to CtripleO
is dinitrogen n1 or n2
it can be both,, but usually its n.1
n.2 usually happens for lanthenides
compare N2 with CO ligands
N2 is worse as a sigma donor and a pi acceptor so complexes tend to be labile
dissociative substitution
u remove the ligand and then add what u have to
the RDS is the loss of the ligand
associative substitution
u add the ligand,, then remove what u have to
the addition is the RDS
when we have an Oh,, do we want an associative or dissociative process
we prefer a dissociative process,, bc we would get 16e- vs 20e- if we were to have an associative one.
what substitution favours 18e- species
dissociative,, would rather have a 16e- transition state than a 20 e- transition state
what can we do to speed up dissociative substitution
we can use high energy photons ,, UV to excite the moelcule and aid in dissociation
dissociation is an internal or external process
its internal making them a lower energy process ,, making it more reactive
what 18e- complexes are more likely to occur with associative susbtitution
the ones with allyls, Cp or arene ligands
but what acc happens is that it is dissociative,, just part of the ligand is dissociating,, not all of it.
aka using n6. aka a hexane with a circle in the middle aka 18e- ,, to a cyclohexane with n4 (using 2 double bonds) and 16e- ,, n.4 to adding the ligand aka 18 once again ,, and then
then u have n6 once u reform the ligand again so its using all 3 double bonds.,, aka 18e-.
16 square planar species like what
they like the associative route bc dissociative route would give u 14e- and we don’t want this.
aka they go 16e- and 4L,, to 18e- and 6L,, to 16e- and 4L once again
when u have a complex of CO ligands,, and u want to complete multiple substitution reactions with PPH3,, why does the rate decrease with each PPh3 addition
lowks sterics and hinderance but this exp is not enough
u need to think that P is the better sigma donor,, better than CO,, meaning theres more pi backbonding to the CO. this means that the MC bond is strengthenes but the CO bond is weakened.
anyways C-Metal is strengthened meaning its rquires more energy and therefore takes more time to be broken in order for PPH3 to substitute it.
okay when u have an Oh with 4CO and 2PPH3 u get what geometry of PPh3
u get fac geometry
whihc doesnt make sense
when u have an Oh with 2PPh3 and 4CO,, what geomtry do u get
u get cis geometry which does make sense
why does PPh3 get put close together when substitutiong it with CO,,
bc CO is a stronger field ligand,, meaning it has a larger trans effect,, meaning when PPh3 is added,, itll substitute lignads accross to it.
PPh3 has less of a trans effect so another PPh3 isnt gonna substitute whatever is across from it.
whats oxidative addition again bc u forgot what it was when he was talking about it lols
think of dihydrogen aka the orthogonal bond ,, turning into dihydride,, aka 2H-.
aka ur oxidising the metal by 2,, and ur adding more ligands and more e- to the e- count
Mg in its free form,, whats its Os
its 0 bc its in its free form
