The choice of wording depends on a few things, including:
- Intent: Are you trying to nudge for a meeting this week?
- Region/dialect: Different parts of English-speaking world use
different wording for politeness.
- Relationship: Is the addressee a peer or a superior?
As a Canadian English speaker, I would say either of your sentences can be used politely, but a few tweaks are needed:
- "in this week": This is unnatural. Use "this week" or "during the week": both are equivalent.
- Question form: Typically, a question form might be seen as less pushy. (Tied to factors 2 and 3 above.)
- Replace "when" with "if": This can only be done if you are willing to give the other person an option to not meet this week. (Tied to factors 1 and 3 above.)
- "your convenient time": This is unnatural. You would use "time convenient for you" if you want to stress on the addressee's convenience or "a convenient time" if you want to talk about a time convenient to both of you.
Putting all this together, one can arrive at many possible sentences. Here are some examples.
I would use this only with someone over whom I have authority:
Let me know when you are free during the week to discuss.
I would use this for a peer or superior if I wanted to give them the option to postpone:
Could you please let me know if you have time to discuss this week?
This is a clever construction that forces the other person to commit to a time this week, but you still make it sound like you are leaving it up to her/him. I would pick one of these if I wanted to push someone with whom I had a formal relationship:
Let me know what time is convenient for a discussion this week.
Could you please let me know what time is convenient this week for a discussion?
Many other answers are possible. We would really need better context to narrow it down.