Multifunctionality in Bimetallic LnIII[WV(CN)8]3− (Ln=Gd,Nd) Coordination Helices: Optical Activity,Luminescence, and Magnetic Coupling

Two chiral luminescent derivatives of pyridine bis(oxazoline) (Pybox), (SS/RR)‐iPr‐Pybox (2,6‐bis4‐isopropyl‐2‐oxazolin‐2‐yl]pyridine) and (SRSR/RSRS)‐Ind‐Pybox (2,6‐bis8H‐indeno1,2‐d]oxazolin‐2‐yl]pyridine), have been combined with lanthanide ions (Gd³⁺, Nd³⁺) and octacyanotungstate(V) metalloligand to afford a remarkable series of eight bimetallic CN^?‐bridged coordination chains: {Ln^III(SS/RR‐iPr‐Pybox)(dmf)₄]₃W^V(CN)₈]₃}_n ? dmf ? 4 H₂O (Ln=Gd, 1 ‐SS and 1 ‐RR; Ln=Nd, 2 ‐SS and 2 ‐RR) and {Ln^III(SRSR/RSRS‐Ind‐Pybox)(dmf)₄]W^V(CN)₈]}_n ? 5 MeCN ? 4 MeOH (Ln=Gd, 3 ‐SRSR and 3 ‐RSRS; Ln=Nd, 4 ‐SRSR and 4 ‐RSRS). These materials display enantiopure structural helicity, which results in strong optical activity in the range 200–450 nm, as confirmed by natural circular dichroism (NCD) spectra and the corresponding UV/Vis absorption spectra. Under irradiation with UV light, the Gd^III‐W^V chains show dominant ligand‐based red phosphorescence, with λ_max≈660 nm for 1 ‐(SS/RR) and 680 nm for 3 ‐(SRSR/RSRS). The Nd^III‐W^V chains, 2 ‐(SS/RR) and 4 ‐(SRSR/RSRS), exhibit near‐infrared luminescence with sharp lines at 986, 1066, and 1340 nm derived from intra‐f ⁴F_3/2→⁴I_{9/2,11/2,13/2} transitions of the Nd^III centers. This emission is realized through efficient ligand‐to‐metal energy transfer from the Pybox derivative to the lanthanide ion. Due to the presence of paramagnetic lanthanide(III) and W^V(CN)₈]^3? moieties connected by cyanide bridges, 1 ‐(SS/RR) and 3 ‐(SRSR/RSRS) are ferrimagnetic spin chains originating from antiferromagnetic coupling between Gd^III (S_Gd=7/2) and W^V (S_W=1/2) centers with J _{1 ‐(SS)}=?0.96(1) cm^?1, J _{1 ‐(RR)}=?0.95(1) cm^?1, J _{3 ‐(SRSR)}=?0.91(1) cm^?1, and J _{3 ‐(RSRS)}=?0.94(1) cm^?1. 2 ‐(SS/RR) and 4 ‐(SRSR/RSRS) display ferromagnetic coupling within their Nd^III‐NC‐W^V linkages.