Briand Glen G, Chivers Tristram, Parvez Masood, Schatte Gabriele
Department of Chemistry, University of Calgary, Alberta, Canada T2N 1N4.
Inorg Chem. 2003 Jan 27;42(2):525-31. doi: 10.1021/ic020562e.
Deprotonation of bis(tert-butylamido)cyclophosph(III/III)azane with organolithium or organomagnesium reagents followed by oxidation with elemental tellurium is a viable approach to the preparation of metal cyclodiphosphazane mono- and ditellurides. The reaction of the cyclodiphosph(III)azane [tBu(H)NP(mu-NtBu)2PN(H)tBu] (1) with elemental tellurium in boiling toluene affords the monotelluride [tBu(H)N(Te)P(mu-NtBu)2PN(H)tBu] (9). A similar reaction involving the magnesium salt MgtBuNP(mu-NtBu)2PNtBu2 (2) also yields a monotelluride Mg[tBuN(Te)P(mu-NtBu)2PNtBu]-(THF)2 (10). By contrast, reaction of the lithium salt Li2tBuNP(mu-NtBu)2PNtBu2 (3) with tellurium results in double oxidation and the formation of the ditellurides Li2tBuN(Te)P(mu-NtBu)2P(Te)NtBu4 (11) and Li2-tBuN(Te)P(mu-NtBu)2P(Te)NtBu2 (12). Compounds 9-12 have been characterized by multinuclear (1H, 7Li, 13C, 31P, and 125Te) NMR, while 9, 10, and 12 have also been characterized by X-ray crystallography. The structure of 9 reveals a typical cis/endo, exo arrangement, with no intermolecular contacts to tellurium. The seco-heterocubic structure, observed in 2, is retained in 10, with the ligand chelating magnesium in an N,N',N"-manner. Unique coordination behavior is exhibited by the ditelluride 12, in which the dianionic ligand is attached to the two lithium centers in both Te,Te' and Te,N bonding modes. Multinuclear NMR data are consistent with retention of the solid-state structures of 9-12 in solution at low temperatures. The reactivity of cyclodiphosph(III/III)azanes toward chalcogens is rationalized by using theoretical calculations (semiempirical PM3 level of theory), which show an inverse correlation between the charge at the phosphorus center and the ease of oxidation.
用有机锂或有机镁试剂使双（叔丁基氨基）环磷（III/III）氮烷去质子化，随后用元素碲氧化，是制备金属环二磷氮烷单碲化物和二碲化物的一种可行方法。环二磷（III）氮烷[tBu(H)NP(μ-NtBu)₂PN(H)tBu]（1）与元素碲在沸腾的甲苯中反应，得到单碲化物[tBu(H)N(Te)P(μ-NtBu)₂PN(H)tBu]（9）。涉及镁盐MgtBuNP(μ-NtBu)₂PNtBu₂（2）的类似反应也生成单碲化物Mg[tBuN(Te)P(μ-NtBu)₂PNtBu]-(THF)₂（10）。相比之下，锂盐Li₂tBuNP(μ-NtBu)₂PNtBu₂（3）与碲反应导致双重氧化，并形成二碲化物Li₂tBuN(Te)P(μ-NtBu)₂P(Te)NtBu₄（11）和Li₂-tBuN(Te)P(μ-NtBu)₂P(Te)NtBu₂（12）。化合物9 - 12已通过多核（¹H、⁷Li、¹³C、³¹P和¹²⁵Te）核磁共振进行了表征，而9、10和12也通过X射线晶体学进行了表征。9的结构显示出典型的顺式/内型、外型排列，与碲没有分子间接触。在2中观察到的亚异立方结构在10中得以保留，配体以N,N',N"-方式螯合镁。二碲化物12表现出独特的配位行为，其中双阴离子配体以Te,Te'和Te,N键合模式连接到两个锂中心。多核核磁共振数据与9 - 12在低温溶液中的固态结构保持一致。通过理论计算（半经验PM3理论水平）对环二磷（III/III）氮烷对硫属元素的反应性进行了合理化解释，计算结果表明磷中心的电荷与氧化的难易程度呈负相关。
