The addition of 2 equiv of n BuLi to a solution of t BuN(H)P(µ-N t Bu) 2 PN(H) t Bu (1) in toluene produces the adduct [LiP(N t Bu) 2 ] 4 ‚0.25P 4 (N t Bu) 6 (2‚0.253), but the reverse addition yields only 2. The structure of 2‚0.253 has been determined by X-ray crystallography: monoclinic, P2 1 /a, a ) 17.649(5) Å, b ) 18.272(4) Å, c ) 20.295(5) Å, β ) 111.92(2)°, V ) 6072(3) Å 3 , and Z ) 4. The tetrameric cluster 2 consists of two P 2 N 2 rings bridged by a tub-shaped, eight-membered Li 4 N 4 ring. The mean P-N distance in the P 2 N 2 rings (1.78 Å) is significantly longer than the corresponding value of 1.65 Å for the P-N bonds linking the P 2 N 2 rings to the Li 4 N 4 unit. The P 4 -(N t Bu) 6 cage 3 in the adduct is formed as the isomer in which two P 2 N 2 rings are bridged by two N t Bu groups. The same tetracyclic isomer of 3 is prepared in 71% yield by the reaction of t BuN(Li)P(µ-N t Bu) 2 PN(Li) t Bu with ClP(µ-N t Bu) 2 PCl in toluene. Variable temperature 31 P{ 1 H} NMR studies of the 16-atom cluster [LiP(N t Bu) 2 ] 4 (2) at different concentrations in C 7 D 8 indicate that facile dissociation into two molecules of the dimer [LiP-(N t Bu) 2 ] 2 occurs above ca. 295 K.

Oxo anions of p‐ and d‐block elements, for example, SiO44−, PO43−, SO42−, and CrO42−, are commonly encountered species. The full or partial replacement of the oxo ligands by isoelectronic imido (NR) groups generates homoleptic polyimido anions of the type [E(NR)x]z− or heteroleptic imidooxo anions with the general formula [OyE(NR)x−y]z− (where E=main group element or transition metal). The alkali metal derivatives of this new class of anions form ternary or quaternary cluster systems, respectively. The structures of these clusters can be rationalized in terms of the self‐assembly of fundamental building blocks. An understanding of the factors that control this process may allow the design of functional materials with specific properties. In addition, these anions are attracting attention as multidentate ligands with unique electronic and stereochemical properties that may engender novel metal‐centered chemistry.

The iminophosphinimide complexes [Ar(R)N]3M(NPNBut) (M = V, Nb) were prepared from the corresponding anionic nitride species ([Ar(R)N]3M identical to NNa)2 by way of a four-step synthetic strategy.

The air oxidation of the cluster compounds [Li(2)E(N(t)Bu)(3)](2) (E = S, Se) in toluene produces deep blue (E = S) or green (E = Se) solutions. The ESR spectra of these solutions consist of a septet (1:3:6:7:6:3:1) of decuplets. The simulation of these spectra shows that the secondary hyperfine splitting results from interaction of the unpaired electron with three equivalent (7)Li ions consistent with the formation of the neutral radicals {Li(3)[E(N(t)Bu)(3)](2)}(*) (4a, E = S, g = 2.0039, a((14)N) = 5.69 G, a((7)Li) = 0.82 G; 4b, E = Se, g = 2.00652, a((14)N) = 5.41 G, a((7)Li) = 0.79 G). Over a period of 25 h the seven line pattern of 4b is replaced first by a five line (1:2:3:2:1) spectrum (g = 2.009, a((14)N) = 13.4 G) and, subsequently, by a three line (1:1:1) spectrum (g = 2.00946, a((14)N) = 15.4 G, a((77)Se) = 4.3 G), neither of which exhibit (7)Li hyperfine splitting. These spectra are tentatively assigned to the radical anions SeO(N(t)Bu)(2)(*)(-) and SeO(2)(N(t)Bu)(*)(-), respectively. The cluster {Li(2)[O(2)S(N(t)Bu)]}(n)() (3) is prepared by the reaction of sulfur dioxide with 2 equiv of LiNH(t)Bu in toluene. The air oxidation of toluene solutions of {Li(2)[OS(N(t)Bu)(2)]}(6) (2a) or 3 produces deep blue species. In the former case the initial ESR spectrum is a 1:2:3:2:1 quintet (g = 2.009, a((14)N) = 13.3 G) which, after 16 h, evolves into a 1:1:1 triplet (g = 2.0088, a((14)N) = 15.9 G). The same triplet is observed in the ESR spectrum of oxidized solutions of 3 leading to the assignments OS(N(t)Bu)(2)(*)(-) and O(2)S(N(t)Bu)(*)(-) for the quintet and triplet, respectively. The disproportionation 2OS(N(t)Bu)(2)(*)(-) --> O(2)S(N(t)Bu)(*)(-) + S(N(t)Bu)(3)(*)(-) is indicated by the changes observed for the ESR spectra of oxidized solutions of 2a.

The reaction of {Al[N(H)Bu t ] 3 } 2 , obtained as a 1 : 2 mixture of cis and trans isomers from the addition of AlCl 3 to three equiv. LiN(H)Bu t in diethyl ether, with LiBu n generates a complex in which a dimeric n-butyllithium fragment is trapped by the trilithiated derivative Li 3 Al 2 [N(H)Bu t ] 3 [N-Bu t ] 3 .