A Consistent Approach to One Coordinate Pnictide Moieties M≡Pn − Using PnH 2 − Salts (M = Zr, Ti; Pn = P, As, Sb)

Establishing a congruent approach to delivering a pnictide atom (Pn$^{3−}$ = P, As, and Sb) to transition metal ions is a challenge, especially for the heavier congeners As and Sb, and when varying the transition metal. We showcase here a convenient route to molecular forms of one coordinate stibide ligands bound to Zr$^{IV}$ and Ti$^{IV}$ ions, represented by the discrete salts [K(L)][(PN)$_2$M≡Sb] (M = Zr (2), Ti (10); PN− = (N-(2-P$^i$Pr$_2$-4-methylphenyl)-2,4,6-Me$_3$C$_6$H$_2$; L = 2,2,2-Kryptofix or 18-C-6 crown-ether/2THF), which were prepared via H$_2$ extrusion from [K(18-C-6)(THF)SbH$_2$] added to the Zr$^{IV}$ cyclometallated-hydride, [(PN)(PN’)Zr(H)] (1), and the Ti$^{II}$ precursor [K(18-C-6)][(PN)$_2$TiCl] (8) respectively. This strategy was extended to the lighter congeners Pn = As, P using [K(18-C-6)(THF)AsH$_2$] (M = Zr (3)), and NaPH$_2$ (M = Ti (6)). Structural and computational studies were applied to understand the bonding trends in the pnictide series, and the role of the metal ion.