Arumugam Kuppuswamy, Selvachandran Malathy, Obanda Antony, Shaw Mohamed C, Chandrasekaran Perumalreddy, Caston Good Sonya L, Mague Joel T, Sproules Stephen, Donahue James P
Department of Chemistry , Wright State University , 3640 Colonel Glenn Highway , Dayton , Ohio 45435-0001 , United States.
Department of Chemistry , Tulane University , 6400 Freret Street , New Orleans , Louisiana 70118-5698 , United States.
Inorg Chem. 2018 Apr 2;57(7):4023-4038. doi: 10.1021/acs.inorgchem.8b00201. Epub 2018 Mar 13.
Compounds of the type [(SCR)M(μ-tpbz)M(SCR)] (R = CN, Me, Ph, p-anisyl; M = Ni, Pd, Pt; tpbz = 1,2,4,5-tetrakis(diphenylphosphino)benzene) have been prepared by transmetalation with [(SCR)SnR'] reagents, by direct displacement of dithiolene ligand from [M(SCR)] with 0.5 equiv of tpbz, or by salt metathesis using Na[SC(CN)] in conjunction with XM(μ-tpbz)MX (X = halide). X-ray crystallography reveals a range of topologies (undulating, chair, bowed) for the (SC)M(PCP)M(SC) core. The [(SCR)M(μ-tpbz)M(SCR)] (R = Me, Ph, p-anisyl) compounds support reversible or quasireversible oxidations corresponding to concurrent oxidation of the dithiolene terminal ligands from ene-1,2-dithiolates to radical monoanions, forming [(SSCR)M(μ-tpbz)M(SSCR)]. The R = Ph and p-anisyl compounds support a second, reversible oxidation of the dithiolene ligands to their α-dithione form. In contrast, [(SC(CN))Ni(tpbz)Ni(SC(CN))] sustains only reversible, metal-centered reductions. Spectroscopic examination of [(SSC( p-anisyl))Ni(μ-tpbz)Ni(SSC( p-anisyl))] by EPR reveals a near degenerate singlet-triplet ground state, with spectral simulation revealing a remarkably small dipolar coupling constant of 18 × 10 cm that is representative of an interspin distance of 11.3 Å. This weak interaction is mediated by the rigid tpbz ligand, whose capacity to electronically insulate is an essential quality in the development of molecular-based spintronic devices.
[(SCR)M(μ - tpbz)M(SCR)]类型的化合物（R = CN、Me、Ph、对甲氧基苯基；M = Ni、Pd、Pt；tpbz = 1,2,4,5 - 四（二苯基膦基）苯）已通过与[(SCR)SnR']试剂进行金属转移反应、用0.5当量的tpbz直接从[M(SCR)]中取代二硫烯配体或使用Na[SC(CN)]与XM(μ - tpbz)MX（X = 卤化物）进行盐复分解反应来制备。X射线晶体学揭示了(SC)M(PCP)M(SC)核心的一系列拓扑结构（起伏状、椅状、弓形）。[(SCR)M(μ - tpbz)M(SCR)]（R = Me、Ph、对甲氧基苯基）化合物支持可逆或准可逆氧化，这对应于二硫烯末端配体从烯 - 1,2 - 二硫醇盐同时氧化为自由基单阴离子，形成[(SSCR)M(μ - tpbz)M(SSCR)]。R = Ph和对甲氧基苯基的化合物支持二硫烯配体的第二次可逆氧化，形成其α - 二硫酮形式。相比之下，[(SC(CN))Ni(tpbz)Ni(SC(CN))]仅支持可逆的、以金属为中心的还原反应。通过电子顺磁共振对[(SSC(对甲氧基苯基))Ni(μ - tpbz)Ni(SSC(对甲氧基苯基))]进行光谱检查，发现其基态近乎简并的单重态 - 三重态，光谱模拟显示其偶极耦合常数非常小，为18×10 cm，代表自旋间距离为11.3 Å。这种弱相互作用是由刚性的tpbz配体介导的，其电子绝缘能力是基于分子的自旋电子器件开发中的一个基本特性。
