Reciting adhkaar when one is junub

It
is permissible for a person, if he is junub, to make du’aa’ to Allaah
and remember Him, including the adhkaar before sleeping and others,
because of what is reported in the hadeeth of ‘Aa’ishah (may Allaah
be pleased with her), who said, “The Messenger of Allaah
(peace and blessings of Allaah be upon him) used to remember Allaah
in all circumstances.” (Narrated by Muslim, al-Hayd, 558). Some
of the commentators on this hadeeth said: this hadeeth is stating a
basic principle, which is the remembrance of Allaah in all circumstances,
even when one is in a state of minor or major impurity. Dhikr in the
form of tasbeeh (saying ‘Subhaan Allaah’), tahleel
(saying ‘Laa ilaaha ill-Allaah’), takbeer (saying ‘Allaahu
akbar’), tahmeed (saying ‘al-hamdu Lillaah’) and other
similar adhkaar is permissible in all situations, according to
the consensus of the Muslims. What is forbidden is dhikr that
consists of reciting Qur’aan, a full aayah or more, whether that is
read from the Mus-haf or recited by heart, because the prohibition of
doing so has been narrated. But it is mustahabb for the person who is
junub to wash his private parts and do wudoo’ when he wants to go to
sleep, because of what is stated in the hadeeth of ‘Umar (may Allaah
be pleased with him), who said, “O Messenger of Allaah, may one of us
sleep when he is junub?” He said, “Yes, if he does wudoo’.” (Narrated
by al-Bukhaari, al-Ghusl, 280) 

See
al-Sharh al-Mumti’ by Ibn ‘Uthaymeen, 1/288; Tawdeeh Ahkaam
by al-Bassaam, 1/250; Fataawa Islamiyyah, 1/232