TY - JOUR

T1 - Experimental assignment of long-range magnetic communication through Pd & Pt metallophilic contacts

AU - Larsen, Emil M. H.

AU - Bonde, Niels A.

AU - Weihe, Hogni

AU - Ollivier, Jacques

AU - Vosch, Tom

AU - Lohmiller, Thomas

AU - Holldack, Karsten

AU - Schnegg, Alexander

AU - Perfetti, Mauro

AU - Bendix, Jesper

PY - 2023

Y1 - 2023

N2 - Record-breaking magnetic exchange interactions have previously been reported for 3d-metal dimers of the form [M(Pt(SAc)(4))(pyNO(2))](2) (M = Ni or Co) that are linked in the solid state via metallophilic PtMIDLINE HORIZONTAL ELLIPSISPt bridges. This contrasts the terminally capped monomers [M(Pt(SAc)(4))(py)(2)], for which neither metallophilic bridges nor magnetic exchange interactions are found. Computational modeling has shown that the magnetic exchange interaction is facilitated by the pseudo-closed shell d(8)MIDLINE HORIZONTAL ELLIPSISd(8) metallophilic interaction between the filled Pt2+ 5d(z)(2) orbitals. We present here inelastic neutron scattering experiments on these complexes, wherein the dimers present an oscillatory momentum-transfer-dependence of the magnetic transitions. This allows for the unequivocal experimental assignment of the distance between the coupled ions, which matches exactly the coupling pathway via the metallophilic bridges. Furthermore, we have synthesized and magnetically characterized the isostructural palladium-analogues. The magnetic coupling across the PdMIDLINE HORIZONTAL ELLIPSISPd bridge is found through SQUID-magnetometry and FD-FT THz-EPR spectroscopy to be much weaker than via the PtMIDLINE HORIZONTAL ELLIPSISPt bridge. The weaker coupling is traced to the larger radial extent of the 5d(z)(2) orbitals compared to that of the 4d(z)(2) orbitals. The existence of a palladium metallophilic interaction is evaluated computationally from potential surface cuts along the metal stretching direction. Similar behavior is found for the PdMIDLINE HORIZONTAL ELLIPSISPd and PtMIDLINE HORIZONTAL ELLIPSISPt-systems with clear minima along this coordinate and provide estimates for the force constant for this distortion. The estimated MMIDLINE HORIZONTAL ELLIPSISM stretching frequencies are found to match experimental observed, polarized bands in single-crystal Raman spectra close to 45 cm(-1). This substantiates the existence of energetically relevant PdMIDLINE HORIZONTAL ELLIPSISPd metallophilic interactions. The unique properties of both Pt2+ and Pd2+ constitutes an orthogonal reactivity, which can be utilized for steering both the direction and strength of magnetic interactions.

AB - Record-breaking magnetic exchange interactions have previously been reported for 3d-metal dimers of the form [M(Pt(SAc)(4))(pyNO(2))](2) (M = Ni or Co) that are linked in the solid state via metallophilic PtMIDLINE HORIZONTAL ELLIPSISPt bridges. This contrasts the terminally capped monomers [M(Pt(SAc)(4))(py)(2)], for which neither metallophilic bridges nor magnetic exchange interactions are found. Computational modeling has shown that the magnetic exchange interaction is facilitated by the pseudo-closed shell d(8)MIDLINE HORIZONTAL ELLIPSISd(8) metallophilic interaction between the filled Pt2+ 5d(z)(2) orbitals. We present here inelastic neutron scattering experiments on these complexes, wherein the dimers present an oscillatory momentum-transfer-dependence of the magnetic transitions. This allows for the unequivocal experimental assignment of the distance between the coupled ions, which matches exactly the coupling pathway via the metallophilic bridges. Furthermore, we have synthesized and magnetically characterized the isostructural palladium-analogues. The magnetic coupling across the PdMIDLINE HORIZONTAL ELLIPSISPd bridge is found through SQUID-magnetometry and FD-FT THz-EPR spectroscopy to be much weaker than via the PtMIDLINE HORIZONTAL ELLIPSISPt bridge. The weaker coupling is traced to the larger radial extent of the 5d(z)(2) orbitals compared to that of the 4d(z)(2) orbitals. The existence of a palladium metallophilic interaction is evaluated computationally from potential surface cuts along the metal stretching direction. Similar behavior is found for the PdMIDLINE HORIZONTAL ELLIPSISPd and PtMIDLINE HORIZONTAL ELLIPSISPt-systems with clear minima along this coordinate and provide estimates for the force constant for this distortion. The estimated MMIDLINE HORIZONTAL ELLIPSISM stretching frequencies are found to match experimental observed, polarized bands in single-crystal Raman spectra close to 45 cm(-1). This substantiates the existence of energetically relevant PdMIDLINE HORIZONTAL ELLIPSISPd metallophilic interactions. The unique properties of both Pt2+ and Pd2+ constitutes an orthogonal reactivity, which can be utilized for steering both the direction and strength of magnetic interactions.

KW - HETEROBIMETALLIC LANTERN COMPLEXES

KW - CENTER-DOT-PT

KW - RELAXATION

KW - SYMMETRY

U2 - 10.1039/d2sc05201f

DO - 10.1039/d2sc05201f

M3 - Journal article

C2 - 36687355

VL - 14

SP - 266

EP - 276

JO - Chemical Science

JF - Chemical Science

SN - 2041-6520

IS - 2

ER -