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Topic: coordination  (Read 2047 times)

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Offline ajolly

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coordination
« on: July 17, 2013, 10:52:48 PM »


How come in coordination compounds the bonding ligand does not receive a charge reflecting its newly established bond?  For example in cisplatin the amine groups are neutral in charge (however they have four bonds) but if the amine was bound to an organic molecule it would receive a formal charge of +1.

Furthermore, why would the oxygen in H2O ever want to coordinate? This seems particularly weird because oxygen typically does not "like" to freely give/share electrons with other atoms.

Sorry to ask what might seem as obvious questions, I am but an undergrad who has taken only 5 semesters worth of chemistry.
CE27 + HE27 + OE27 + NE26 + PE25 + SE24 + CaE25 + KE24 + ClE24 + NaE24 + MgE24 + FeE23 +  FE23 + ZnE22 + SiE22 + CuE21 + BE21 + IE20 + SnE20 + MnE20 + SeE20 + CrE20 + NiE20 + MoE19 + CoE19 + VE18 ='S Me (not methane)

Offline Hunter2

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Re: coordination
« Reply #1 on: July 18, 2013, 01:12:30 AM »
The ligand offer lone pair electrons, to set them in an d-Orbital of the metal atom. The charge will not be changes.
In case of amines or ammonia its different case.

A positiv hydrogen or alcyl gruppe reacts and transfer the charge.  NRR'R'' + R'''+ => NRR'R''R'''+  R = Alcyl, H

Offline orgo814

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Re: coordination
« Reply #2 on: August 15, 2013, 11:11:24 PM »
This link sort of explains how electrons "behave" in metal complexes. It may or may not be of help to you based on where your confusion lies. It will assume, however, that you are familiar with the 18 electron rule and pi back bonding. If not, take a look at that first.

Good luck.

http://employees.csbsju.edu/cschaller/Reactivity/coordchem/coordchem%20electron.htm

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