Bifunctional chelates with mixed aromatic and aliphatic amine donors for labeling of biomolecules with the {Tc(CO) 3} + and {Re(CO) 3} + cores

Abstract

A series of tridentate ligands consisting of mixed aromatic and aliphatic amine derivatives of single amino acid chelates and phenylpiperazine have been developed, and their reactions with [NEt 4] 2[ReBr 3(CO) 3] have been investigated. The compounds [Re(CO) 3{(NC 5H 4CH 2)NCH 3(C 2H 4)NHCH 3}]Br ( 4), [Re(CO) 3{(NC 5H 4CH 2)NCH 3(C 2H 4)NCH 3(CH 2) x COOC 2H 5}]Br ( x = 1, 5; x = 4, 6) [Re(CO) 3{(NC 5H 4CH 2)NH(C 2H 4)N(CH 3) 2}]Br ( 7), [Re(CO) 3{(NC 5H 4CH 2)N(CH 2COOC 2H 5)(C 2H 4)N(CH 3) 2}]Br ( 8) and [Re(CO) 3(NC 5H 4CH 2)(C 2H 4NH 2)N(CH 2) 3–CH 3Ophenpip]Br ( 9) (phenpip: phenylpiperazine, –C 6H 4–(CH 2CH 2) 2N–) were prepared and characterized by elemental analysis, NMR, IR, HSMS and X-ray crystallography. All complexes exhibit fac-{Re(CO) 3N 3} coordination geometry in the cationic molecular unit. Crystal data for C 13H 17BrN 3O 3Re ( 4): orthorhombic, Pbca, a = 13.4510(8) Å, b = 10.5728(6) Å, c = 22.5378(13) Å, V = 3205.2(3) Å 3, Z = 8; C 17H 23BrN 3O 5Re ( 5): orthorhombic, Pcca, a = 16.5907(7) Å, b = 14.8387(6) Å, c = 16.7075(7) Å, V = 4113.1(3) Å 3, Z = 8; C 13H 25BrN 3O 7Re ( 7 · 4H 2O): monoclinic, P2 1/ n, a = 14.0698(17) Å, b = 9.6760(12) Å, c = 15.6099 (19) Å, β = 114.930(2)°, V = 1927.1(4) Å 3, Z = 4; C 17H 23BrN 3O 5Re ( 8): monoclinic, P2 1/ n, a = 7.5312(5) Å, b = 16.0366(10) Å, c = 16.8741(10) Å, β = 98.9990(10)°, V = 2012.9(2) Å 3, Z = 4.