Heteroatom-bearing ligands and metal complexes thereof

A compound of the following formula Ia, Ib or Ic:

• ##STR63## ##STR64## where Q is the group --(C(RR)).sub.m 1--Y.sup.1 --(C(RR).sub.m2 --(Y.sup.2 --(C(RR)).sub.m3).sub.n --, where Y.sup.1 is --NR-- and Y.sup.2 is --NR--, --O--, --S--, --SO--, --SO.sub.2 --, or --Se--;
• n is an integer selected from 0 or 1;
• and m1, m2 and m3 are integers independently selected from 0 to 4, provided that the sum of m1 and m2 is greater than zero;
• with the proviso that if the R of --NR-- of Y.sup.1 is not hydrogen, and n=0, then either m1=0 or m2=0;
• all R and R* groups are independently:
• (i) R.sup.2 ;
• (ii) halogen;
• (iii) --OR.sup.2 ;
• (iv) --C(O)--OR.sup.2 ;
• (v) --C(O)--N(R.sup.2).sub.2 ;
• (vi) --N(R.sup.2).sub.2 ;
• (vii) --alkyl--C(O)--OR.sup.2 ;
• (viii) --alkyl--C(O)--N(R.sup.2).sub.2 ;
• (ix) --alkyl--N(R.sup.2).sub.2 ;
• (x) --aryl--C(O)--OR.sup.2 ;
• (xi) --aryl--C(O)--N(R.sup.2).sub.2 ;
• (xii) --aryl--N(R.sup.2).sub.2 ;
• (xiii) acyl;
• (xiv) acyloxy;
• (xv) heterocyclo;
• (xvi) hydroxyalkyl;
• (xvii) --SO.sub.2 --R.sup.2 ;
• (xviii) --alkyl--SO.sub.2 --R.sup.2 ;
• (xix) --(A)p--R.sup.3, where A is a linking group, p is 0 or a positive integer, and R.sup.3 is a bioactive moiety;
• or
• (xx) two R groups, or an R group and an R* group, taken together with the one or more atoms to which they are bonded, form a saturated or unsaturated, spiro or fused, carbocyelic or heterocyclic ring which may be unsubstituted or substituted by one or more groups selected from the groups (i) to (xix) above;
• with the proviso that a carbon atom bearing an R group is not directly bonded more than one heteroatom;
• R.sup.1 is hydrogen, a thiol protecting group, or the group --(A)p--R.sup.3 defined above;
• and
• R.sup.2 is independently hydrogen, alkyl, alkenyl, alkynyl, or aryl.