Different orientations of P(O) versus C(O) in P(O)NHC(O) skeleton have been discussed in two new phosphorus(V)-nitrogen compounds with formula XP(O)Y and XP(O)Z2 where X = NHC(O)C6H4(4-F) and Y = NHCH2C(CH3)2CH2NH (1), Z = NHC6H4(4-CH3) (2). Compound 1 is the first example of an aliphatic diazaphosphorinane with a gauche orientation which has been studied by X-ray crystallography; the P=O bond is in the equatorial position of the ring. Both compounds show n J(F,C) and m J(F,H) coupling constants (n = 1, 2, 3 and 4; m = 3 and 4) and 3 J(P,C) > 2 J(P,C). Quantum chemical calculations were performed with HF and Density Functional Theory (DFT) methods using 6−31+G(d,p) basis set. A tentative assignment of the observed vibrational bands for these molecules is discussed. Compound 1 shows a deshielded C atom of the carbonyl moiety (in 13C NMR spectrum) relative to that of 2, which is supported by IR spectroscopy in which the considerably lower C=O frequency is observed for 1. Comparing the X-ray crystallography and IR spectra of 1 and 2 shows that the acyclic compound 2, containing P=O and C=O bonds in an anti position, are involving in a stronger N–H···O=P hydrogen bond in crystal network. This leads to a weaker P=O and NC(O)NHP(O)–H bonds and stronger N···O interaction. The Namide–H is involved in an intramolecular N–H···O hydrogen bond.
讨论了 P(O)NHC(O)骨架中 P(O)和 C(O)的不同取向,这两种新的
磷(V)-氮化合物的
化学式分别为 XP(O)Y 和 XP(O)Z2 其中 X ;= NHC(O)
C6H4(4-F),Y = NHCH2C(
CH3)2CH2NH (1),Z = NH (4- ) (2)。化合物 1 是通过 X 射线晶体学研究的第一个具有高位取向的脂肪族二氮杂膦烷的实例;P=O 键位于环的赤道位置。这两种化合物都显示出 n J(F,C)和 m J(F,H)耦合常数(n = 1、2、3 和 4;m = 3 和 4)和 3 J(P,C) > 2 J(P,C)。量子
化学计算采用高频和密度泛函理论(DFT)方法,使用 6-31+G(d,p) 基集。本文讨论了观察到的这些分子振动带的暂定分配。与 2 相比,化合物 1 的羰基 C 原子(在 13C NMR 光谱中)呈去屏蔽状态,这一点也得到了红外光谱的支持,在红外光谱中观察到 1 的 C=O 频率要低得多。比较 1 和 2 的 X 射线晶体学和红外光谱可以发现,无环化合物 2 的 P=O 和 C=O 键处于反位置,在晶体网络中形成了较强的 N-H-O=P 氢键。这导致 P=O 和 NC(O)NHP(O)-H 键变弱,而 N-O 相互作用变强。Namide-H 参与分子内 N-H-O 氢键。