Reactions of Sodium Bis(N-aryliminophosphoranyl)alkanides with Halide-Bridged Platinum(II) and Palladium(II) Phosphine Dimers Affording Four-Membered M−N−P−C Metallacycles and Orthometalated Platinum(II) and Palladium(II) Complexes

Abstract

Reaction of the sodium bis(iminophosphoranyl)alkanide compounds Na[CR‘‘(PPh2NC6H4R‘-4)2] (1a, R‘‘ = H, R‘ = CH3; 1b, R‘‘ = H, R‘ = OCH3; 1c, R‘‘ = CH3, R‘ = CH3) with M2X4(PR3)2 (M = Pt, Pd; X = Cl, Br; PR3 = PEt3, PMe2Ph) yields the four-membered metallacycles MX(PR3){CR‘‘(PPh2NC6H4R‘-4)2} (2a−f, M = Pt; 3a−c, M = Pd), containing the bis(iminophosphoranyl)alkanide ligand coordinated in a σ-C,σ-N chelating fashion. The molecular structure of 2e (X = Cl, PR3 = PMe2Ph, R‘‘ = CH3, R‘ = CH3) has been determined by X-ray crystallography. The 1,1-bis(iminophosphoranyl)ethanide ligand (1c) in 2e is σ-C,σ-N-chelated toward the square-planar-surrounded Pt, with N coordinated trans to PMe2Ph (Pt−N = 2.132(4) Å) and C trans to Cl (Pt−C = 2.116(4) Å), resulting in a puckered M−N−P−C metallacycle and one noncoordinated phosphinimine moiety. In solution the complexes 2 and 3 undergo a dynamic process, involving an intermediate (for 2) or fast (for 3) N,N‘ exchange of coordinated and noncoordinated PN groups. Heating (to 60−80 °C) or prolonged stirring of solutions of the kinetically obtained four-membered metallacycles 2 and 3 gives the orthometalated complexes PtX(PR3){2-C6H4PPh(NHC6H4R‘-4)CHPPh2 NC6H4R‘-4} (4a−d,f) and PdCl(PR3){2-C6H4PPh(NC6H4Me-4)CHPPh2NHC6H4Me-4} (5a,c). The X-ray crystal structure of 4a (X = Cl, PR3 = PEt3, R‘ = CH3) has been determined. The new mononuclear orthometalated Pt complexes 4 contain a σ-C,σ-C‘ coordinated [2-C6H4PPh(NHC6H4R-4‘)CR‘‘PPh2NC6H4R‘-4]- ligand, in which the ortho-H (Ph) has shifted to a bridge position between the two noncoordinating nitrogen atoms. The four-membered platinacycles 2a,b and the orthometalated platinacycles 4a,b react with 1 equiv of HBF4 or CF3COOH to give 6a,b and 7a,b, respectively, by protonation of the noncoordinated PNC6H4R‘-4 groups only. Addition of CO2 to 2a,d and 4c,f results in an aza-Wittig reaction, giving PtCl(PR3){CH(PPh2NC6H4R‘-4)(PPh2O)} (8a,d) and PtX(PR3){2-C6H4PPh(O)CHPPh2NHC6H4R‘-4} (9c,f), respectively, together with aryl isocyanate and bis(aryl)carbodiimide.

Syntheses and structures of dimeric sodium and potassium complexes of 2,6-diisopropyl-anilidophosphine borane ligand

“…Thus, it can be concluded that no interaction between phosphorus and sodium atoms is observed. The bond distances Na1-N1 2.3828(16), Na1-O1 2.3112 (17), and Na1-O2 2.3631(18) Å are in the range of previously reported values. 63 The P1-B1 bond distance (1.920(2) Å) remains almost unchanged compared to that of the free ligand 1-H (1.908(3) Å).…”

“…57,61 Chelation from ligand 1 to two sodium atoms via two amido nitrogen atoms and hydrogen atoms of the two BH 3 groups exhibits a tub-shaped Na 2 P 2 N 2 (BH 3 ) 2 core with mean bond angles N1-P1-B1 106.72 (9) • and N2-P2-B2 110.20 (9) • . The Na1-P1 3.3056(8) distance of 3.3056(8) Å is slightly longer than the bond distances of 2.9661 (17) 62 and it is larger than the sum of the covalent radii (3.00 Å) of 14, P1-B1-K1 106.16 (14), C13-K1-B1 64.34 (8), C13-N1-P1 127.5(2), K1 ′ -B1-K1 98.46(9), B1 ′ -K1-B1 81.54 (9). sodium and phosphorus.…”

“…1,2 Recently, there has been significant research effort in employing inorganic amines and imines to study coordination chemistry. The P-N ligand systems such as monophosphanylamides (R 2 PNR') [3][4][5][6][7] diphosphanylamides ((Ph 2 P) 2 N), 4,[8][9][10][11] phosphoraneiminato (R 3 PN), 12,13 phosphiniminomethanides ((RNPR' 2 ) 2 CH), [15][16][17][18][19][20][21][22] phosphinimin-methandiides ((RNPR' 2 ) 2 C), [23][24][25][26][27] and diimino-phosphinates (R 2 P(NR')) [28][29][30][31] are well-known as ligands and have proved their importance in transition and rare earth metal chemistry. We have recently introduced a series of phosphineamines [Ph 2 PNHR] (A) (R = 2,6-Me 2 C 6 H 3 CHPh 2 ,C P h 3 ) and their chalcogen derivatives [Ph 2 P(O)NHR] (NPO), [Ph 2 P(S)NHR] (NPS)and [Ph 2 P(Se)NHR] (NPSe) (chart 1) to the chemistry of alkali metals and the heavier alkaline earth metals.…”

Water‐Induced Rearrangement of a Platinacyclic Carbene Produces a Platinacyclic Carbaphosphazene with an Intraannular PtC Bond in a PtNPNPC Ring

“…[10,21,22,23] The C(1), P(1), N(1), and P(2) atoms in 3 are coplanar as they are in 2. The P À N bond lengths in the {P=N=P} + fragment (1.607(2) and 1.583(2) ) and P-N-P angle (128.4(1)8) are similar to those in 2 (1.593(2) and 1.599(2) , and 123.2(2)8).…”

Water‐Induced Rearrangement of a Platinacyclic Carbene Produces a Platinacyclic Carbaphosphazene with an Intraannular PtC Bond in a PtNPNPC Ring

“…[10,21,22,23] The C(1), P(1), N(1), and P(2) atoms in 3 are coplanar as they are in 2. [10,21,22,23] The C(1), P(1), N(1), and P(2) atoms in 3 are coplanar as they are in 2.…”