US Patent 7109250 Multimer forms of acylphosphines and their derivatives

Compounds of the formula (I), in which E is O or S; and x is 0 or 1, A is cyclopentyl, cyclohexyl, naphthyl, biphenylyl, anthracyl or an O-, S- or N-containing 5- or 6-membered heterocyclic ring, where the mentioned radicals are unsubstituted or substituted by halogen, C1–C4alkyl or C1–C4alkoxy; or A is a group formula (II) R is C1–C24alkyl, unsubstituted or substituted, C2–C24alkyl which is interrupted once or more than once by nonconsecutive O, S or NR14 and which is unsubstituted or substituted, C2–C24alkenyl which is uninterrupted or interrupted once or more than once by nonconsecutive O, S or NR14 and which is unsubstituted or substituted, C5–C24cycloalkenyl which is uninterrupted or interrupted once or more than once by nonconsecutive O, S or NR14 and which is unsubstituted or substituted; C7–C24arylalkyl which is unsubstituted or substituted on the aryl group. C4–C24cycloalkyl which is uninterrupted or interrupted once or more then once by O, S or NR14 and which is unsubstituted or substituted, C8–C24arylcycloalkyl or C8–C24arylcycloalkenyl; or, R is a group of the formula (III) W is a bond, —CO—O— or —CO—N(R15)—; L a di-tri-or tetravalent linking group, n is a number of 2,3 or 4;