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.

In the solid state, OP[N(H)Me](3) (1a) and OP[N(H)(t)Bu](3) (1b) have hydrogen-bonded structures that exhibit three-dimensional and one-dimensional arrays, respectively. The lithiation of 1b with 1 equiv of (n)BuLi generates the trimeric monolithiated complex (THF)[LiOP(N(t)Bu)[N(H)(t)Bu](2)](3) (4), whereas reaction with an excess of (n)BuLi produces the dimeric dilithium complex [(THF)(2)Li(2)OP(N(t)Bu)(2)[N(H)(t)Bu]](2) (5). Complex 4 contains a Li(2)O(2) ring in an open-ladder structure, whereas 5 embraces a central Li(2)O(2) ring in a closed-ladder arrangement. Investigations of the lithiation of tris(alkyl or arylamido)thiophosphates, SP[N(H)R](3) (2a, R = (i)Pr; 2b, R = (t)Bu; 2c, R = p-tol) with (n)BuLi reveal interesting imido substituent effects. For the alkyl derivatives, only mono- or dilithiation is observed. In the case of R = (t)Bu, lithiation is accompanied by P-S bond cleavage to give the dilithiated cyclodiphosph(V/V)azane [(THF)(2)Li(2)[((t)BuN)(2)P(micro-N(t)Bu)(2)P(N(t)Bu)(2)]] (9). Trilithiation occurs for the triaryl derivatives EP[N(H)Ar](3) (E = S, Ar = p-tolyl; E = Se, Ar = Ph), as demonstrated by the preparation of [(THF)(4)Li(3)[SP(Np-tol)(3)]](2) (10) and [(THF)(4)Li(3)[SeP(NPh)(3)]](2) (11), which are accompanied by the formation of small amounts of 10.[LiOH(THF)](2) and 11.Li(2)Se(2)(THF)(2), respectively.

The ambidentate dianions [tBuN(E)P(μ-NtBu)2P(E)NtBu]2- (5a, E = S; 5b, E = Se) are obtained as their disodium and dipotassium salts by the reaction of cis-[tBu(H)N(E)P(μ-NtBu)2P(E)N(H)tBu] (6a, E = S; 6b, E = Se), with 2 equiv of MN(SiMe3)2 (M = Na, K) in THF at 23 °C. The corresponding dilithium derivative is prepared by reacting 6a with 2 equiv of tBuLi in THF at reflux. The X-ray structures of five complexes of the type [(THF) x M]2[tBuN(E)P(μ-NtBu)2P(E)NtBu] (9, M = Li, E = S, x = 2; 11a/11b, M = Na, E = S/Se, x = 2; 12a, M = K, E = S, x = 1; 12b, M = K, E = Se, x = 1.5) have been determined. In the dilithiated derivative 9 the dianion 5a adopts a bis (N,S)-chelated bonding mode involving four-membered LiNPS rings whereas 11a,b and 12a,b display a preference for the formation of six-membered MNPNPN and MEPNPE rings, i.e., (N,N ‘ and E,E ‘)-chelation. The bis-solvated disodium complexes 11a,b and the dilithium complex 9 are monomeric, but the dipotassium complexes 12a,b form dimers with a central K2E2 ring and associate further through weak K···E contacts to give an infinite polymeric network of 20-membered K6E6P4N4 rings. The monoanions [tBu(H)N(E)P(μ-NtBu)2P(E)NtBu)]- (E = S, Se) were obtained as their lithium derivatives 8a and 8b by the reaction of 1 equiv of nBuLi with 6a and 6b, respectively. An X-ray structure of the TMEDA-solvated complex 8a and the 31P NMR spectrum of 8b indicate a N,E coordination mode. The reaction of 6b with excess tBuLi in THF at reflux results in partial deselenation to give the monolithiated P(III)/P(V) complex {(THF)2Li[tBuN(Se)P(μ-NtBu)2PN(H)tBu]} 10, which adopts a (N,Se) bonding mode.

The treatment of Me3SiN=P(NHBut)3 with three equivalents of LiBun in toluene produces (Li3(P(NBut)3(NSiMe3)))2 comprised of a Li6N6 cyclic ladder capped on the two hexagonal faces by mu 3-PNSiMe3 groups; the corresponding reaction of O=P(NHBut)3 yields the face-sharing double-cubane (Li2(THF)P(O)(NBut)2(NHBut))2 with a central Li2O2 ring.

Lithiation of SP[N(H)R]3 with LiBun produces the dimers [(THF)LiSP(NR)(NHR)2]2 (R = Pri) or ([LiSP(NR)-(NHR)2][(THF)LiSP(NR)2(NHR)])2 (R = But) with central Li2N2 or Li2S2 rings, respectively; further lithiation yields the dianion [SP(NR)2(NHR)]2- (R = Pri) or leads to sulfur extrusion when R = But.