Sequestration and release of carbon dioxide

A method for reversible capture and release of carbon dioxide comprising the steps of:

• providing a solution of a tetranuclear complex or mixture thereof, in which absorption sites are provided by coordinated solvent molecules such as water molecules;
• exposing the solution to the atmosphere or to a gas stream containing carbon dioxide to sequester carbon dioxide;
• and
• adjusting the pH of the resultant reaction mixture to facilitate the release of carbon dioxide,
• wherein the solution which is used to sequester carbon dioxide is a solution of a tetranuclear transition metal compound having the formula:
• w[M4(μ-O)x(μ-OH)y(L)2(H2O)4].z(solvent) Compound A
• wherein the tetranuclear transition metal compound that has sequestered carbon dioxide is of the formula:
• w[M4(μ-O)x(μ-OH)y(L)2(O2CR1)(O2CR2)1].z(solvent) Compound B
• and wherein the tetranuclear transition metal compound that is formed as a result of the pH induced release of carbon dioxide from Compound B is of the formula:
• w[M4(μ-O)x(μ-OH)y(L)2(H2O)4].z(solvent) Compound A
• wherein
• w is any ion or mixture of ions in appropriate stoichiometries for compounds A or B to be electronically neutral,
• M is selected from one or more of Fe, Al and Ga or one or more of Mn, Ru, Zn, Cr, Co, Ni, In, Cu and V,
• x and y are numerical values the sum of which equals to 2,
• L is any suitable aminocarboxylic acid ligand that stabilises the tetranuclear complexes,
• R1 and R2=any sidegroup or combination of two sidegroups from the following list:
• an oxygen atom, an OH group, a hydrazine or hydrazinium moiety, an ammonia or ammonium moiety or any primary, secondary or tertiary aliphatic or aromatic amine or ammonium moiety and their derivatives including diamine, triamine or alcohol amine or corresponding ammonium moieties, O2CR1 or O2CR2=any carbamate or carbamic acid moiety.
• Z may be 0 or any positive number, and
• solvent is any suitable solvent.

A compound selected from:

• w[Fe4(μ-O)(μ-OH)(hpdta)2(CO3)2].x sol (1),
• w[Fe4(μ-O)(μ-OH)(hpdta)2(O2CNHC3H6NH3)2].x sol (2),
• w[Fe4(μ-O)(μ-OH)(hpdta)2(O2CNHNH3)2].x sol (3),
• w[Fe4(μ-O)(μ-OH)(hpdta)2(O2CNHC4H8NH3)2].x sol (4),
• w[Fe4(μ-O)(μ-OH)(hpdta)2(O2CNHC6H12NH3)2].x sol (5),
• w[Fe4(μ-O)(μ-OH)(hpdta)2(O2CNHCH14NH3)2].x sol (6),
• w[Fe4(μ-O)(μ-OH)(hpdta)2(O2CNHC2HNC4H8NH2)2].xsol (7),
• w[Fe4(μ-O)(μ-OH)(hpdta)2(O2CNHC3H7)2].xsol (8),
• w[F4(μ-O)(μ-OH)(hpdta)2(O2CNHCH2CH2NCH2CH2NH13)2].xsol (9),
• w[Fe4(μ-O)(μ-OH)(hpdta)2(O2CNHCH2CH2OH)2].xsol (10),
• w[Fe4(μ-O)(μ-OH)(hpdta)2(O2CNHC2H4NH3)2].x sol (11),
• w[AlIII4(μ-O)(μ-OH)(hpdta)2(CO3)2].sol (12),
• w[Al4(μ-O)(μ-OH)(hpdta)(O2CNHC2H4NH3)2].x sol (13),
• w[Al4(μ-O)(μ-OH)(hpdta)2(O2CNHNH3)2].x sol (14),
• w[Al4(μ-O)(μ-OH)(hpdta)2(O2CNHC4H8NH3)2].x sol (15),
• w[Al4(μ-O)(μ-OH)(hpdta)2(O2CNHC6H2NH3)2].x sol (16),
• w[Al4(μ-O)(μ-OH)(hpdta)2(O2CNHC7H14NH3)2].x sol (17),
• w[Al4(μ-O)(μ-OH)(hpdta)2(O2CNHC2H4NC4H8NH2)2].xsol (18),
• w[Al4(μ-O)(μ-OH)(hpdta)2(O2CNHC3H7)2].xsol (19),
• w[Al4(μ-O)(μ-OH)(hpdta)2(O2CNHCH2CH2HNCH2CH2NH3)2].sol (20),
• w[Al4(μ-O)(μ-OH)(hpdta)2(O2CNHCH2CH2OH)2].xsol (21),
• w[CuIII4(μ-O)(μ-OH)(hpdta)2(CO3)2].sol (22),
• w[Cu4(μ-O)(μ-OH)(hpdta)2(O2CNHC2H4NH13)2].x sol (23),
• w[Cu4(μ-O)(μ-OH)(hpdta)2(O2CNHC2H4NH3)2].x sol (24),
• w[Cu4(μ-O)(μ-OH)(hpdta)2(O2CNHNH3)2].x sol (25),
• w[Cu4(μ-O)(μ-OH)(hpdta)2(O2CNHC4H8NH3)2].x sol (26),
• w[Cu4(μ-O)(μ-OH)(hpdta)2(O2CNHC6H12NH13)2].x sol (27),
• w[Cu4(μ-O)(μ-OH)(hpdta)2(O2CNHC7H14NH3)2].x sol (28),
• w[Cu4(μ-O)(μ-OH)(hpdta)2(O2CNHC2H4C4H8NH2)2].xsol (29),
• w[Cu4(μ-O)(μ-OH)(hpdta)2(O2CNHC3H7)2].xsol (30),
• w[Cu4(μ-O)(μ-OH)(hpdta)2(O2CNHCH2CH2HNCH2CH2NH32].xsol (31),
• w[Cu4(μ-O)(μ-OH)(hpdta)2(O2CNHCH2CH2OH)2].xsol (32),
• w[GaIII4(μ-O)(μ-OH)(hpdta)2(CO3)2].sol (33),
• w[Ga4(μ-O)(μ-OH)(hpdta)2(O2CNHC2H4NH3)2].x sol (34),
• w[Ga4(μ-O)(μ-OH)(hpdta)2(O2CNHC2H4NH3)2].x sol (35),
• w[Ga4(μ-O)(μ-OH)(hpdta)2(O2CNHNH3)2].x sol (36),
• w[Ga4(μ-O)(μ-OH)(hpdta)2(O2CNHC4H8NH3)2].x sol (37),
• w[Ga4(μ-O)(μ-OH)(hpdta)2(O2CNHC6H12NH3)2].x sol (38),
• w[Ga4(μ-O)(μ-OH)(hpdta)2(O2CNHC7H14NH3)2].x sol (39),
• w[Ga4(μ-O)(μ-OH)(hpdta)2(O2CNHC2H4NC4H8NH2)2].xsol (40),
• w[Ga4(μ-O)(μ-OH)(hpdta)2(O2CNHC3H7)2].xsol (41),
• w[Ga4(μ-O)(μ-OH)(hpdta)2(O2CNHCH2CH2HNCH2CH2NH3)2].xsol (42),
• w[Ga4(μ-O)(μ-OH)(hpdta)2(O2CNHCH2CH2OH)2].xsol (43),
• w[Mn4(μ-O)(μ-OH)(hpdta)2(CO3)2].sol (44),
• w[Mn4(μ-O)(μ-OH)(hpdta)2(O2CNHC2H4NH3)2].x sol (45),
• w[Mn4(μ-O)(μ-OH)(hpdta)2(O2CNHC2H4NH3)2].x sol (46),
• w[Mn4(μ-O)(μ-OH)(hpdta)2(O2CNHC2H4NH3)2].x sol (47),
• w[Mn4(μ-O)(μ-OH)(hpdta)2(O2CNHC4H8NH3)2].x sol (48),
• w[Mn4(μ-O)(μ-OH)(hpdta)2(O2CNHC6H12NH3)2].sol (49),
• w[Mn4(μ-O)(μ-OH)(hpdta)2(O2CNHC7H14NH3)2].x sol (50),
• w[Mn4(μ-O)(μ-OH)(hpdta)2(O2CNHC2H4NC4H8NH2)2].xsol (51),
• w[Mn4(μ-O)(μ-OH)(hpdta)2(O2CNHC3H7)2].xsol (52),
• w[Mn4(μ-O)(μ-OH)(hpdta)2(O2CNHCH2CH2HNCH2CH2NH3)2].xsol (53),
• w[Mn4(μ-O)(μ-OH)(hpdta)2(O2CNHCH2CH2OH)2].xsol (54),
• w[Cr4(μ-O)(μ-OH)(hpdta)2(CO3)2].sol (55),
• w[Cr4(μ-O)(μ-OH)(hpdta)2(O2CNHC2H4NH3)2].x sol (56),
• w[Cr4(μ-O)(μ-OH)(hpdta)2(O2CNHC2H4NH3)2].x sol (57),
• w[Cr4(μ-O)(μ-OH)(hpdta)2(O2CNHNH3)2].x sol (58),
• w[Cr4(μ-O)(μ-OH)(hpdta)2(O2CNHC4H8NH3)2].x sol (59),
• w[Cr4(μ-O)(μ-OH)(hpdta)2(O2CNHC6H12NH3)2].x sol (60),
• w[Cr4(μ-O)(μ-OH)(hpdta)2(O2CNHC7H14NH3)2].x sol (61),
• w[Cr4(μ-O)(μ-OH)(hpdta)2(O2CNHC2H4C4H8NH2)2].xsol (62),
• w[Cr4(μ-O)(μ-OH)(hpdta)2(O2CNHC3H7)2].xsol (63), and
• w[Cr4(μ-O)(μ-OH)(hpdta)2(O2CNHCH2CH2HNCH2CH2NH3)2].xsol (64).