TY - JOUR
T1 - On the reaction of Ph2PNHPPh2 with RNCS (R = Et, Ph, p-NO2C6H4)
T2 - Preparation of the zwitterionic ligand EtNHC(S)Ph2P=NPPh2C(S)NEt (HSNS) and the zwitterionic metalate [(SNS)Rh(CO)]
AU - Asti, Mattia
AU - Cammi, Roberto
AU - Cauzzi, Daniele
AU - Graiff, Claudia
AU - Pattacini, Roberto
AU - Predieri, Giovanni
AU - Stercoli, Alessandro
AU - Tiripicchio, Antonio
PY - 2005/5/20
Y1 - 2005/5/20
N2 - The reaction of Ph2PNHPPh2 (PNP) with RNCS (Et, Ph, p-NO2-(C6H4)) gives addition products resulting from the attack of the P atoms of PNP on the electrophilic carbon atom of the isothiocyanate. When PNP is reacted with EtNCS in a 1:2 molar ratio, the zwitterionic molecule EtNHC(S)PPh2=NP+Ph 2C(S)N-Et (HSNS) is obtained in high yield. HSNS can be protonated (H2SNS+) or deprotonated (SNS-), behaving in the latter form as an S,N,S-donor pincer ligand. The reaction of HSNS with [(acac)Rh(CO)2] (acac = acetylacetonate) affords the zwitterionic metalate [(SNS)Rh(CO)]. Other products can be obtained depending on the R group, the PNP/RNCS ratio (1:1 or 1:2), and the reaction temperature. The proposed product of the primary attack of PNP on RNCS, Ph2PN=PPh2C(S)NHR (A), cannot be isolated. Reaction of A with another RNCS molecule leads to 1:2 addition compounds of the general formula RNHC(S)PPh2=NP+ Ph2C(S)N-R (1), which can rearrange into the non-zwitterionic product RNHC(S)PPh2=NP(S)Ph2 (2) by eliminating a molecule of RNC. Two molecules of A can react together, yielding 1:1 PNP/RNCS zwitterionic products of the formula RNHCH[PPh2= NP(S)Ph 2]PPh2=NP+Ph2C(S)N-R (3). Compound 3 can then rearrange into RNHCH[PPh2=NP(S)Ph 2]2 (4) by losing a RNC molecule. When R = Et (a), compounds 1a, 2a (HSNS), and 4a have been isolated and characterized. When R = Ph (b), compounds 2b and 4b can be prepared in high yield. When R = p-NO 2C6H4 (c), only compound 3c is observed and isolated in high yield. The crystal structures of HSNS, [(SNS)Rh(CO)], and of the most representative products have been determined by X-ray diffraction methods.
AB - The reaction of Ph2PNHPPh2 (PNP) with RNCS (Et, Ph, p-NO2-(C6H4)) gives addition products resulting from the attack of the P atoms of PNP on the electrophilic carbon atom of the isothiocyanate. When PNP is reacted with EtNCS in a 1:2 molar ratio, the zwitterionic molecule EtNHC(S)PPh2=NP+Ph 2C(S)N-Et (HSNS) is obtained in high yield. HSNS can be protonated (H2SNS+) or deprotonated (SNS-), behaving in the latter form as an S,N,S-donor pincer ligand. The reaction of HSNS with [(acac)Rh(CO)2] (acac = acetylacetonate) affords the zwitterionic metalate [(SNS)Rh(CO)]. Other products can be obtained depending on the R group, the PNP/RNCS ratio (1:1 or 1:2), and the reaction temperature. The proposed product of the primary attack of PNP on RNCS, Ph2PN=PPh2C(S)NHR (A), cannot be isolated. Reaction of A with another RNCS molecule leads to 1:2 addition compounds of the general formula RNHC(S)PPh2=NP+ Ph2C(S)N-R (1), which can rearrange into the non-zwitterionic product RNHC(S)PPh2=NP(S)Ph2 (2) by eliminating a molecule of RNC. Two molecules of A can react together, yielding 1:1 PNP/RNCS zwitterionic products of the formula RNHCH[PPh2= NP(S)Ph 2]PPh2=NP+Ph2C(S)N-R (3). Compound 3 can then rearrange into RNHCH[PPh2=NP(S)Ph 2]2 (4) by losing a RNC molecule. When R = Et (a), compounds 1a, 2a (HSNS), and 4a have been isolated and characterized. When R = Ph (b), compounds 2b and 4b can be prepared in high yield. When R = p-NO 2C6H4 (c), only compound 3c is observed and isolated in high yield. The crystal structures of HSNS, [(SNS)Rh(CO)], and of the most representative products have been determined by X-ray diffraction methods.
KW - Heterocycles
KW - Rhodium
KW - Synthetic methods
KW - Tridentate ligands
KW - Zwitterions
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U2 - 10.1002/chem.200400906
DO - 10.1002/chem.200400906
M3 - Article
C2 - 15798977
AN - SCOPUS:19944374137
VL - 11
SP - 3413
EP - 3419
JO - Chemistry - A European Journal
JF - Chemistry - A European Journal
SN - 0947-6539
IS - 11
ER -