Magnetic Coupling between Metal Spins through the 7,7,8,8‐Tetracyanoquinodimethane (TCNQ) Dianion

Abstract

A family of magnetic metal-organic frameworks, (Ph3PMe)2[M2(TCNQ)3] {M=Fe(2+), Co(2+), Ni(2+) and Zn(2+)} have been prepared and structurally characterized. The honeycomb-like "layers" consist of M(II) ions doubly bridged with dinitrilomethane moieties of two 7,7,8,8-tetracyanoquinodimethane (TCNQ) dianions which are further connected through phenyl rings to form a 3D dianionic framework [M2TCNQ3](2-) with Ph3PMe(+) cations filling cavities that run along the c axis. Studies of the magnetic coupling through the TCNQ dianion in these structures revealed that it can promote long-range magnetic ordering despite the long coupling pathway.

Noncovalent Functionalization of Black Phosphorus

“…In stark contrast, the BP‐TCNQ complex exhibited a doublet for the cyano group at 2199 and 2168 cm −1 , indicative of the formation of TCNQ .− , as well as a shoulder at around 2131 cm −1 , related to the formation TCNQ 2− (see Figure S2). These observations are in accord with those for previously reported samples of TCNQ 2− ‐containing coordination polymers, and point towards the formation of an anionic TCNQ species on BP under inert conditions, as previously predicted by theoretical calculations …”

Magnetic ordering in TCNQ-based metal–organic frameworks with host–guest interactions

“…Infrared spectral data, summarized in Table 2, indicate the presence of ν(CuN) stretching modes characteristic of TCNQ 2− . 10 The lower energies of these bands as compared to previously reported compounds indicate a slightly higher negative charge on the TCNQ 2− units, consistent with chargetransfer from aromatic guest molecules to the TCNQ 2− units.…”

“…9 In this vein, we and another group recently studied the magnetic properties of a series of anionic frameworks of the type [M 2 (TCNQ) 3 ] 2− (M = Mn, Fe, Co, Ni) and it was found that the TCNQ 2− ligand promotes long range magnetic ordering despite the long coupling pathway. 10 The lack of accessible cavities in these three-dimensional materials, however, precluded the possibility of enhancing magnetic and electronic properties via post-synthetic modifications or interactions with small guest molecules.…”

New CuI2(TCNQ–II) and CuI2(F4TCNQ–II) Coordination Polymers

“…8 Easily obtained TCNQH 2 , structure II, affords a very convenient starting material for the synthesis of an extensive range of coordination polymers of the TCNQ 2-ligand in a form suitable for single crystal X-ray diffraction studies. [9][10][11][12][13][14][15] In contrast to earlier coordination polymers of the TCNQ -· radical anion in which the TCNQ moieties are in close contact, the TCNQ 2-ligands in the derived coordination polymers are commonly, spatially well separated. One of our longer term objectives is to partially oxidise such TCNQ 2--based coordination polymers to a mixed TCNQ 1-/TCNQ 2- 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 68.996°, no.…”