He wrote tunes to provide capital (6)
I believe the answer is:
berlin
'capital' is the definition.
(capital of Germany)
'he wrote tunes' is the wordplay.
'he' becomes 'Ber'.
'wrote tunes' becomes 'lin' (I can't justify this - if you can you should give a lot more credence to this answer).
'ber'+'lin'='BERLIN'
'to provide' acts as a link.
Can you help me to learn more?
(Other definitions for berlin that I've seen before include "Capital of Germany" , "Composer of White Christmas" , "Irving -, Russian-born musical composer" , "Isaiah, say?" , "City once divided by wall" .)