Formation of an imidazoliumyl-substituted [(L_C)₄P₄]⁴⁺tetracation and transition metal mediated fragmentation and insertion reaction (L_C= NHC)

Abstract

Tetracationic cyclo-tetraphosphane [(LC)4P4]4+ as triflate salt (LC = 4,5-dimethyl-1,3-diisopropyl-imidazol-2-yl) is obtained from the reduction of [LCPCl2]+ with 1,4-bis(trimethylsilyl)-1,4-dihydropyrazine and represents the first salt of the cationic cyclo-phosphane series with the general formula [LnPn]n+.

Functionalization of Pentaphosphorus Cations by Complexation

“…However, the coordination chemistry of cationic polyphosphanes has scarcely been studied thus far. In contrast to a variety of neutral compounds I – IV (Figure ) and anionic compounds V – VII , cationic polyphosphorus complexes with late transition metals (such as VIII ) are extremely rare . In particular, the direct use of cationic polyphosphanes as ligands has not been investigated.…”

“…The 1 J PP coupling constants obtained by iterative fitting (−324.7 Hz to −400.2 Hz) are typical for P−P single bonds, while the 2 J PP coupling constants ( 2 J AE =−3.9 Hz, 2 J AM =−7.7 Hz, 2 J MY =80.3 Hz, 2 J EX =50.0 Hz, 2 J XY =−6.4 Hz) span a large range. Small 2 J PP couplings such as 2 J AE and 2 J AM are typical for tetracoordinate P atoms …”

“…In contrast to avariety of neutral compounds I-IV [16][17][18][19] (Figure 1) and anionic compounds V-VII, [10,19] cationic polyphosphorus complexes with late transition metals (such as VIII)a re extremely rare. [20] In particular,t he direct use of cationic polyphosphanes as ligands has not been investigated. This prompted us to study whether cationic polyphosphane complexes are accessible by reaction of Figure 1.…”

“…Small 2 J PP couplings such as 2 J AE and 2 J AM are typical for tetracoordinate Patoms. [19][20][21][22][23] Table S17 for thermal enthalpies and free enthalpies).…”

Functionalization of Pentaphosphorus Cations by Complexation

“…[15] However,t he coordination chemistry of cationic polyphosphanes has scarcely been studied thus far. [20] In particular,t he direct use of cationic polyphosphanes as ligands has not been investigated. [20] In particular,t he direct use of cationic polyphosphanes as ligands has not been investigated.…”