TY - JOUR
T1 - Synthesis of stable platinum complexes containing carborane in a carrier group for potential BNCT agents
AU - Yoo, Jeongsoo
AU - Do, Youngkyu
PY - 2009
Y1 - 2009
N2 - A series of stable platinum complexes containing closo-carborane cages in a 'carrier group', which could be potentially utilized for boron neutron capture therapy (BNCT), was successfully synthesized and characterized by various spectroscopic methods. Two ortho-closo-carborane cages were connected to the 3,3′ or 4,4′-positions of 2,2′-bipyridine through ester bonds to give three carborane-linked bipyridine ligands, 3,3′-(3-(1,2-dicarba- closo-dodecaborane-1-yl)propoxycarbonyl)-2,2′-bipyridine (3) and n,n′-(3-(1-methyl-1,2-dicarba-closo-dodecaborane-1-yl)propoxycarbonyl)-2, 2′-bipyridine (n = 3 4; n = 4 5). The prepared ligands successfully replaced the labile benzonitrile groups of [Pt(PhCN) 2Cl 2] to afford three cisplatin analogs [Pt(L)Cl 2] (L = 3-5). In order to increase their aqueous solubility, three carboplatin analogs, [Pt(L)(CBDCA), L = 4 and 5, CBDCA = 1,1-cyclobutanedicarboxylate] and [Pt(4)(oxalate)], were synthesized by employing [Pt(DMSO) 2(CBDCA)] or [Pt(DMSO) 2(oxalate)] as a starting platinum(ii) source. Two platinum(iv) complexes [Pt(L)Cl 4, L = 4 and 5] were also successfully prepared from Na 2[PtCl 6]·6H 2O. All of the synthesized platinum complexes containing closo-carboranes exhibited excellent stability in both the solid and solution states and could be stored in air for several months. Even though the three closo-carborane ligands were successfully deboronated to the corresponding nido-mono anions by employing a mild degradation method involving CsF/ethanol, all attempts at the incorporation of nido-carborane-linked bipyridine into the platinum complexes failed, leading to the formation of black precipitates of reduced platinum.
AB - A series of stable platinum complexes containing closo-carborane cages in a 'carrier group', which could be potentially utilized for boron neutron capture therapy (BNCT), was successfully synthesized and characterized by various spectroscopic methods. Two ortho-closo-carborane cages were connected to the 3,3′ or 4,4′-positions of 2,2′-bipyridine through ester bonds to give three carborane-linked bipyridine ligands, 3,3′-(3-(1,2-dicarba- closo-dodecaborane-1-yl)propoxycarbonyl)-2,2′-bipyridine (3) and n,n′-(3-(1-methyl-1,2-dicarba-closo-dodecaborane-1-yl)propoxycarbonyl)-2, 2′-bipyridine (n = 3 4; n = 4 5). The prepared ligands successfully replaced the labile benzonitrile groups of [Pt(PhCN) 2Cl 2] to afford three cisplatin analogs [Pt(L)Cl 2] (L = 3-5). In order to increase their aqueous solubility, three carboplatin analogs, [Pt(L)(CBDCA), L = 4 and 5, CBDCA = 1,1-cyclobutanedicarboxylate] and [Pt(4)(oxalate)], were synthesized by employing [Pt(DMSO) 2(CBDCA)] or [Pt(DMSO) 2(oxalate)] as a starting platinum(ii) source. Two platinum(iv) complexes [Pt(L)Cl 4, L = 4 and 5] were also successfully prepared from Na 2[PtCl 6]·6H 2O. All of the synthesized platinum complexes containing closo-carboranes exhibited excellent stability in both the solid and solution states and could be stored in air for several months. Even though the three closo-carborane ligands were successfully deboronated to the corresponding nido-mono anions by employing a mild degradation method involving CsF/ethanol, all attempts at the incorporation of nido-carborane-linked bipyridine into the platinum complexes failed, leading to the formation of black precipitates of reduced platinum.
UR - http://www.scopus.com/inward/record.url?scp=67649126468&partnerID=8YFLogxK
U2 - 10.1039/b823193a
DO - 10.1039/b823193a
M3 - Article
C2 - 19662290
AN - SCOPUS:67649126468
SN - 1477-9226
SP - 4978
EP - 4986
JO - Dalton Transactions
JF - Dalton Transactions
IS - 25
ER -