Abstract: The invention relates to rare earth cryptates consisting of at least one rare earth salt complexed by a macropolycyclic compound corresponding to one of formulae I or II below, in which:the ring ##STR1## is the N.sub.2 O.sub.4 macrocycle, the N.sub.2 O.sub.3 macrocycle or the bis--bipyridine macrocycle;Y is a spacer arm or group which consists of a divalent organic radical selected from linear or branched C.sub.1 to C.sub.20 alkylene groups optionally containing one or more double bonds and/or optionally being interrupted by one or more heteroatoms such as oxygen, nitrogen, sulfur or phosphorus, or from C.sub.5 to C.sub.8 cycloalkylene groups or C.sub.6 to C.sub.14 arylene groups, the said alkylene or arylene groups optionally being substituted by alkyl, aryl or sulfonate groups;Z is a functional group capable of bonding covalently with a biological substance;R is a methyl group or represents the group --Y--Z; andR' is hydrogen or a group --COOR", in which R" is a C.sub.1 to C.sub.

Abstract: The invention relates to rare earth cryptates consisting of at least one rare earth salt complexed by a macropolycyclic compound corresponding to one of formulae I or II below, in which:the ring ##STR1## is the N.sub.2 O.sub.4 macrocycle, the N.sub.2 O.sub.3 macrocycle or the bis-bipyridine macrocycle;Y is a spacer arm or group which consists of a divalent organic radical selected from linear or branched C.sub.1 to C.sub.20 alkylene groups optionally containing one or more double bonds and/or optionally being interrupted by one or more heteroatoms such as oxygen, nitrogen, sulfur or phosphorus, or from C.sub.5 to C.sub.8 cycloalkylene groups or C.sub.6 to C.sub.14 arylene groups, the said alkylene or arylene groups optionally being substituted by alkyl, aryl or sulfonate groups;Z is a functional group capable of bonding covalently with a biological substance;R is a methyl group or represents the group --Y--Z; andR' is hydrogen or a group --COOR", in which R" is a C.sub.1 to C.sub.

Abstract: The invention relates to rare earth cryptates consisting of at least one rare earth salt complexed by a macropolycyclic compound corresponding to one of formulae I or II below, in which:the ring ##STR1## is the N.sub.2 O.sub.4 macrocycle, the N.sub.2 O.sub.3 macrocycle or the bis-bipyridine macrocycle;Y is a spacer arm or group which consists of a divalent organic radical selected from linear or branched C.sub.1 to C.sub.20 alkylene groups optionally containing one or more double bonds and/or optionally being interrupted by one or more heteroatoms such as oxygen, nitrogen, sulfur or phosphorus, or from C.sub.5 to C.sub.8 cycloalkylene groups or C.sub.6 to C.sub.14 arylene groups, the said alkylene or arylene groups optionally being substituted by alkyl, aryl or sulfonate groups;Z is a functional group capable of bonding covalently with a biological substance;R is a methyl group or represents the group --Y--Z; andR' is hydrogen or a group --COOR", in which R" is a C.sub.1 to C.sub.

Abstract: The invention relates to rare earth cryptates consisting of at least one rare earth salt complexed by a macropolycyclic compound corresponding to one of formulae I or II below, in which:the ring ##STR1## is the N.sub.2 O.sub.4 macrocycle, the N.sub.2 O.sub.3 macrocycle or a bis-bipyridine macrocycle;Y is a spacer arm or group which consists of a divalent organic radical selected from linear or branched C.sub.1 to C.sub.20 alkylene groups optionally containing one or more double bonds and/or optionally being interrupted by one or more heteroatoms such as oxygen, nitrogen, sulfur or phosphorus, or from C.sub.5 to C.sub.8 cycloalkylene groups or C.sub.6 to C.sub.