Abstract
Reduction of [Re02(en)2]+, [Re02(NH3)4]+, or [Re02(ampy)2]+ (en= ethylenediamine; ampy= 2-(aminomethyl)-
pyridine) in HC1 (aq) produces [ReCl2(en)2]+, [ReCl2(NH3)4]+, and [ReCl2(ampy)2]+ respectively. Chloride
substitution on Zrnnr-[ReCl2(en)2]+ by pyridine, isonicotinamide, nicotinamide, 4-picoline, 4-(dimethylamino)-
pyridine, and n-propylamine is accomplished with accompanying isomerization to a cis geometry. The crystal
structures of [ReCl2(en)2](PF6) (triclinic; £1 (No. 2); a= 8.717(1) k,b= 12.618(2) A, c= 6.523(1) A, a=
98.44(2)°,ß= 102.66(1)°, y= 78.50(1)°; > = 2.543 g/cm3 4;Z= 2), [ReCl2(ampy)2](BPh4),(triclinic;£1 (No.
2); a= 12.334(1) A, b= 17.345(2) A, c= 8.918(1) A, a= 91.30(3)°, ß= 94.75(3)°, y= 73.29(2)°; * <* =1.551
g/cm3; Z= 2), and [ReCl(picoline)(en)2](PF6)2, (monoclinic; P2\/c (No. 14); a= 9.233(3) A, b= 17.824(5) A,
c= 13.979(5) A, ß= 108.15(3)°; Aaicd= 2.202 g/cm3; Z= 4) are reported, and various equilibrium constants
are determined which pertain to the relative affinity of Re(II) and of Re(III) for -acid ligands. Parallels are drawn
to the established -bases [Ru(NH3)5]2+ and [Os(NH3)5]2+.
