Questions about dative covalent bond and complexes

[chatelier]

does an atom necessarily becomes +1 charged after forming a dative covalent bond with another atom?

just like something I learned in organic chem:
C6H5-H2N:+ H+ ------> C6H5-H2N+→H
the positive charge of H+ is transferred to the N atom as N forms a dative covalent bond with it.

analogically, in a transition metal complex like [Cu(H2O)6]2+, will each H2O molecule becomes +1 charged after forming dative covalent bond with Cu2+ ?

but should that be the case, Cu will then become -4 charged as 6 H2O molecules have formed dative covalent bonds with it...

but that sounds strange ^ ^ @@@@@

 

[Astronuc]

Perhaps this would be of help - http://www.chemguide.co.uk/atoms/bonding/dative.html

If an atom were to lose 1 electron, it would effectively assume a +1 charge.

But look at the example of carbon monoxide, CO.

 

[chatelier]

well the web says the +ve charge should spread over the whole of the complex, so that means in no way can i know the charge on a specific atom?

also, how can i know when the charge will spread over and when it won't? just like the example quoted from the website, the positive charge will just stay on the N atom in NH3BF3.

hey i really got confused with dative covalent bond now.

 

[chatelier]

But look at the example of carbon monoxide, CO.

um...actually how can the example of CO help me understand the structure of [Cu(H2O)6]2+ ?

 

[chatelier]

seems no one can help...~~