Information recording medium and oxonol compound
An optical information recording medium has a recording layer coposed essentially of an oxonol compound of the following formula: in which each of R 1 , R 2 and R 3 is a substituent group X k+ is an onium ion, each of p and q is an integer of 0 to 4, r is an integer of 1 to 5, n is 0 or 1, k is an integer of 1 to 10, and in the case that p or q is an integer of 2 or more, plural substituent groups represented by R 1 or R 2 are the same or different or they can connect with each other to form a ring.
1 . An information recording medium comprising a substrate and a recording layer provided thereon on which information can be recorded by irradiation with a laser beam, wherein the recording layer comprises an oxonol compound of the following formula (1) in which at least one carbon atom of the methine chain comprises a substituent group of (R 3 ) r :
in which each of R 1 , R 2 and R 3 independently represents a substituent group other than hydrogen, X k+ represents an onium ion, each of p and q independently is an integer of 0 to 4, r is an integer of 1 to 5, n is 0 or 1, k is an integer of 1 to 10, and in the case where p or q is an integer of 2 or more, plural substituent groups represented by R 1 or R 2 are the same or different or they can connect with each other to form a ring.
2 . The information recording medium of claim 1 , wherein each of R 1 , R 2 and R 3 of the formula (1) independently is an alkyl group having 1-18 carbon atoms, an alkenyl group having 2-18 carbon atoms, an alkynyl group having 2-18 carbon atoms, an aryl group having 6-14 carbon atoms, a heterocyclic group having 4-9 carbon atoms, a halogen atom, nitro group, cyano group, or a group represented by —COR 11 , —SO 2 R 11 , —SOR 11 , —CO 2 R 11 , —OR 11 , —SR 11 , —OCOR 11 , —OSO 2 R 11 , —CONR 11 R 12 , —SO 2 NR 11 R 12 , —OCONR 11 R 12 , —OSO 2 N—R 11 R 12 , —NR 11 R 12 , NR 11 COR 12 , NR 11 SO 2 R 12 , NR 11 CO 2 R 12 , —NR 11 CONR 12 R 13 , OR—NSO 2 NR 12 R 13 in which each of R 11 , R 12 and R 13 independently represents an alkyl group having 1-18 carbon atoms, an alkenyl group having 2-18 carbon atoms, an alkynyl group having 2-18 carbon atoms, an aryl group having 6-14 carbon atoms, or a heterocyclic group having 4-9 carbon atoms.
3 . The information recording medium of claim 1 , wherein X k+ is a quaternary ammonium ion.
4 . The information recording medium of claim 1 , wherein X k+ is an onium ion of the following formula (2):
in which each of R 4 and R 5 independently represents an alkyl group, an alkenyl group, an alkynyl group, an aryl group, or a heterocyclic group; each R 6 and R 7 independently represents a substituent group; each of s and t independently represents an integer of 0 to 4; and in the case where s or t is an integer of 2 or more, plural substituent groups represented by R 6 and R 7 is the same or different or they can connect with each other to form a ring.
5 . The information recording medium of claim 1 , wherein a light-reflecting layer is further provided on the recording layer.
6 . An oxonol compound having the following formula (3):
in which R represents a substituent group selected from the group consisting of methyl, ethyl, phenyl, 4-pyridyl, methoxy and phenoxy; n is 0 or 1, X k+ represents an onium ion; and k is 1 or 2.
7 . An information recording medium comprising a substrate and a recording layer provided thereon on which information can be recorded by irradiation with a laser beam, wherein the recording layer comprises an oxonol compound of claim 6.